BACKGROUND:CD47 has been identified as an innate immune checkpoint and found to be associated with inferior survival in various types of cancer. However, the critical role of CD47 in gastric cancer and its association with tumor associated macrophages remain unclear. METHODS:Tumor tissues of gastric cancer from Zhongshan Hospital and data from GSE62254, GSE84437 and TCGA datasets were analyzed. Immunohistochemistry was performed to detect the expression of CD47, CD11c, CD163 and CD68 in gastric cancer tissues. Kaplan-Meier curves and Cox model were used for comparing the clinical outcomes of patients belonging to different subgroups. RESULTS:Gastric cancer patients with high CD47 expression exhibited poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy (ACT). A positive correlation was found between M1-polarized macrophage infiltration and CD47 expression in gastric cancer; however, the prognostic value of M1-polarized macrophages was attenuated in CD47-high gastric cancer patients. Moreover, we found that CD47 mRNA level was enriched in microsatellite-instable (MSI) subtype of gastric cancer and associated with ARID1A mutation and FGFR2 signaling pathway activation. CONCLUSIONS:Aberrant CD47 expression represented an independent predictor for adverse survival outcome and ACT resistance in gastric cancer. Targeting CD47 might be a promising strategy for gastric cancer patients.

Pt(ii)-based antitumor drugs (e.g. cisplatin and oxaliplatin) are one of the most successful and frequently used drugs in cancer chemotherapy at present. However, drug resistance and severe side effects are the major problems in the application of platinum drugs. Detoxification of Pt(ii) drugs is one of the most important mechanisms of drug resistance. Herein, a supramolecular Pt(iv) prodrug nano-assembly delivery system is designed and used to encapsulate a γ-glutamyl transferase (GGT) inhibitor (OU749) (Pt-CD/Dex-Ad@OU nano-assemblies) for the synergistic chemotherapy of cisplatin-resistant cancer. Pt-CD/Dex-Ad@OU nano-assemblies could be efficiently taken up by cisplatin-resistant cancer cells and release a drug in the intracellular reductive environment. The Pt-CD/Dex-Ad@OU nano-assemblies can efficiently suppress the expression of GGT, depleting GSH and augmenting ROS via the reduction of the Pt(iv) prodrug. Thereby, by breaking the redox balance the detoxification and antiapoptosis mechanisms of Pt(ii) drugs can be overcome. Thereafter, the excellent therapeutic efficacy of Pt-CD/Dex-Ad@OU nano-assemblies is validated on a cisplatin-resistant human non-small cell lung cancer (A549/DDP) model. Furthermore, the inhibition of GGT protein is expected to reduce the nephrotoxicity of cisplatin. Collectively, this study provides a promising strategy to break the redox balance for overcoming drug resistance and maximizing the efficacy of platinum-based cancer therapy.

Gamma-glutamyltransferase (γ-GGT) is a membrane-bound enzyme that is involved in biotransformation, nucleic acid metabolism, and tumourigenesis. Elevated serum γ-GGT levels are related to an increased cancer risk and worse prognosis in many cancers. In the present study, we evaluated the prognostic value of preoperative serum γ-GGT in patients with hepatocellular carcinoma (HCC) who underwent liver transplantation (LT). A total of 130 HCC patients after LT were included in the study. The optimal cut-off value of γ-GGT was 128U/L by receiver operating characteristic analysis, with a sensitivity and specificity of 60.0% and 72.9%, respectively. Elevated preoperative serum γ-GGT was significantly associated with high alpha-fetoprotein (AFP), large tumor size, and macro- and micro-vascular invasion. The 1-, 3-, 5-year disease-free survival (DFS) and overall survival (OS) rates of HCC patients in the γ-GGT > 128U/L group were poorer than those in the γ-GGT ≤ 128U/L group. Stratification analysis revealed that γ-GGT exhibited a greater predictive value for DFS and OS in HCC patients beyond the Milan criteria and no macro-vascular invasion. In conclusion, elevated preoperative serum γ-GGT was significantly associated with advanced tumor stage and aggressive tumor behaviors, and serum γ-GGT can be considered as a prognostic factor for HCC patients after LT, especially for patients beyond the Milan criteria or without macro-vascular invasion.

Tumor-derived exosomes can modulate the cancer microenvironment and induce metastatic spread. Exosomes may carry enzymes for leukotriene (LT) biosynthesis, but the role of exosomal LTs has not been studied in cancer. We isolated exosomes and malignant cells from pleura exudates from 14 patients with non-small cell lung cancer. Lipidomic profiles, migration and apoptosis were determined. Both exosomes and primary cancer cells contained γ-glutamyl transpeptidase 1 (GGT-1) and avidly transformed exogenous LTC to pro-tumorigenic LTD, for the cells to levels 100-fold above their endogenous CysLT production. This suggests that cancer cells promote their own survival via LTD if supplied with LTC, which in the exudates was produced by monocytic cells. Furthermore, exosomes promoted migration of cancer cells, which was counteracted by the CysLT1 antagonist montelukast. Montelukast also induced apoptosis of cancer cells, and this was partially inhibited by exosomes. Our results demonstrate how cancer cells and exosomes, together with monocytic cells in lung cancer tissue, can produce high amounts of LTD, to stimulate cancer cell migration and survival. This suggests that part of the pro-metastatic effect of exosomes is mediated by the leukotriene machinery, further supporting the use of CysLT1 antagonists for lung cancer therapy.

AIMS:Helicobacter pylori (Hp) infection plays an important role in the development of gastric cancer. Hp can secrete gamma-glutamyltransferase (GGT), however, the impact of GGT of Hp on the human gastric cells is not clear. Although it has been demonstrated that ten-eleven translocation 1 (TET1) is overexpressed in gastric cancer, the relationship between the GGT of Hp and TET1 has not been studied. The aim of this study was to explore the relationship between GGT and TET1, and the role of TET1 in the development of gastric cancer induced by Hp was also explored. MATERIALS AND METHODS:The correlation between TET1 and prognosis of gastric adenoma cancer was analyzed by bioinformatics. The GGT gene of Hp26695 was knocked out by electroporation with plasmid to construct the GGT knockout strain of Hp (Hp-KS-1). The shTET1 lentivirus transfected GES-1, MGC-803 and SGC-7901 cell lines were constructed. The biological characteristics of the three kind of cells were detected. KEY FINDINGS:TET1 was overexpressed in gastric tissues of Hp infected patients and mice. Bioinformatics analysis showed that in patients with gastric cancer, higher TET1 expression would result in poorer prognosis. The GGT gene of Hp can lead to overexpression of TET1 in GES-1, MGC-803 and SGC-7901 cells, along with the activation of Wnt/β-catenin signaling pathway, and then promoting tumorigenesis. After silencing TET1, the Wnt/β-catenin signaling pathway which was activated by GGT of Hp was inhibited. SIGNIFICANCE:GGT of Helicobacter pylori can promote gastric carcinogenesis by activating Wnt/β-catenin signaling pathway trough up-regulating TET1.

BACKGROUND:High serum enzyme activity levels of γ-glutamyl transferase (GGT) are associated with increased risk of mortality, but whether this is mediated by fatty liver, as a common cause of high GGT levels, is uncertain. Our aim was to test whether GGT levels are associated with all-cause, cancer, and cardiovascular (CVD) mortality, independently of fatty liver. METHODS:In an occupational cohort (n = 278 419), causes of death (International Statistical Classification of Diseases and Related Health Problems, 10th revision) were recorded over 7 years. Liver function tests and liver fat [measured by ultrasonographic standard criteria or fatty liver index (FLI)] were assessed at baseline. We used Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% CIs of all-cause, cancer, and CVD mortality for GGT quartiles (with lowest GGT quartile as reference). RESULTS:There were 136, 167, 265, and 342 deaths across increasing GGT quartiles. After adjusting for liver fat (by ultrasound diagnosis) in the fully adjusted model, all-cause and cancer mortality were increased in the highest GGT quartile [HR 1.50 (95% CI 1.15-1.96) and 1.57 (1.05-2.35), respectively]. For CVD mortality, the hazard was attenuated: HR 1.35 (95% CI 0.72-2.56). After adjusting for FLI in the fully adjusted model, HRs for all-cause, cancer, and CVD mortality were 1.46 (0.72-2.56), 2.03 (1.02-4.03), and 1.16 (0.41,3.24), respectively. CONCLUSIONS:There were similar hazards for all-cause and cancer mortality and attenuated hazards for CVD mortality for people in the highest GGT quartile, adjusting for fatty liver assessed by either ultrasound or FLI.

BACKGROUND/AIM:Serum γ-glutamyltransferase (GGT) is reportedly associated with survival and therapeutic response in various malignancies; however, as far as we are aware its impact on metastatic castration-resistant prostate cancer (mCRPC) has never been assessed. PATIENTS AND METHODS:Fifty consecutive men with mCRPC receiving enzalutamide at a single cancer center were retrospectively evaluated. The primary endpoint was overall survival (OS) and the secondary endpoints were prostate-specific antigen (PSA) response, maximal PSA change, and PSA progression-free survival (PSA-PFS). RESULTS:Multivariable analysis demonstrated that elevation of GGT (≥40 U/l) was significantly and independently associated with shorter OS (hazard ratio(HR)=3.61; p=0.004), as were lower hemoglobin (HR=6.04; p<0.001) and higher PSA (HR=4.38; p=0.009). Elevated GGT was also associated with poorer PSA response, maximal PSA change, and shorter PSA-PFS. CONCLUSION:Elevated GGT was an adverse prognostic indicator in men with mCRPC receiving enzalutamide. External validations would improve the generality of our findings.

BACKGROUND:There has been no clinically useful diagnostic or prognostic biomarker for renal cell carcinoma (RCC). Serum γ-glutamyltransferase (GGT) activity has been reported to be a prognostic marker for several types of cancer including RCC. Exosomes or small extracellular vesicles present in body fluids have potential as a biomarker. We have recently demonstrated that GGT activity on exosomes isolated from serum is useful for the differential diagnosis of prostate cancer and benign prostate hyperplasia. In this study, we aimed to examine if serum exosomal GGT activity could be a marker for RCC. METHODS:We examined GGT1 expression and GGT activity in cell lysates and exosomes from culture medium of HK-2 proximal tubule epithelial and RCC cell lines. GGT activity was measured using a fluorescent probe for GGT, γ-glutamyl hydroxymethyl rhodamine green. Serum and serum exosomal GGT activities were measured in patients with RCC. GGT1 expression in RCC tissues was evaluated by immunohistochemical staining. RESULTS:GGT1 levels in exosomes from KMRC-1, OS-RC-2 and 786-O cells were elevated compared with those from HK-2 cells. In exosomes, GGT1 expression correlated with GGT activity determined using a fluorescent probe for GGT. In RCC patients, serum exosomal GGT activity was elevated in those with advanced stages (III/IV vs. I/II, p = 0.037) and those with microvascular invasion (with vs. without, p = 0.034). Immunohistochemical analysis showed that membranous GGT1 expression was increased in RCC with microvascular invasion. Notably, preoperative serum exosomal GGT activity could predict the likelihood of having microvascular invasion diagnosed by pathological examination of surgically resected specimens. CONCLUSIONS:Our results suggest that serum exosomal GGT activity could be a clinically useful marker for advanced clinicopathological features of RCC patients, and its combined use with conventional diagnostic modalities may improve the diagnosis and treatment of patients.

BACKGROUND:Serum gamma-glutamyltransferase (GGT) has been reported to be correlated with survival in a variety of malignancies. However, its effect on patients with bladder cancer (BC) treated by radical cystectomy has never been evaluated. PATIENTS AND METHODS:We retrospectively evaluated 263 patients who underwent radical surgery in our center. Baseline features, hematologic variables, and follow-up data were obtained. The endpoints included overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). The relationship between GGT and survival were evaluated. RESULTS:The median follow-up period for all patients was 34.7 (22.9-45.9) months. At the last follow-up, 67 patients died, 51 patients died of cancer, 92 patients experienced disease recurrence. Patients with an elevated serum GGT had a higher rate of pT3-T4 tumors. Patients with a higher preoperative serum GGT had a lower rate of OS, CSS and DFS (P < 0.001 for all). Multivariate analysis identified that preoperative serum GGT was independent predictor of OS (HR: 3.027, 95% CI: 1.716-5.338; P < 0.001), CSS (HR: 2.115, 95% CI: 1.093-4.090; P = 0.026), DFS (HR: 2.584, 95% CI: 1.569-4.255; P < 0.001). Age, diabetes history, pathologic T stage, and lymph node status also were independent predictors of prognosis for BC patients. CONCLUSIONS:Our results indicated that preoperative serum GGT was an independent prognosis predictor for survival of BC patients after radical cystectomy, and can be included in the prognostic models.

OBJECTIVES:Serum γ-glutamyltransferase (GGT) is reportedly associated with prognosis in patients with various malignancies. However, the prognostic role of GGT is unknown among patients with advanced urothelial carcinoma (aUC). This study was designed to examine the prognostic role of serum GGT in patients with aUC. MATERIALS AND METHODS:Charts of 125 consecutive aUC patients (inoperable cT4 and/or metastasis to lymph nodes/distant organs) managed at a single cancer center between 2004 and 2016 were retrospectively reviewed. Variables collected included age, sex, body mass index, Karnofsky performance status, primary site, clinical tumor stage, lymph node/visceral metastasis, hepatic comorbidities, the presence of curative treatment before the diagnosis of aUC, white blood cell count, neutrophil-to-lymphocyte ratio, hemoglobin, albumin, lactate dehydrogenase, alkaline phosphatase, GGT, C-reactive protein, and treatments given after the diagnosis of aUC. Associations of variables with overall survival (OS) were analyzed using the Cox proportional hazard model. RESULTS:Serum GGT was elevated (≥60 U/l) at the diagnosis of aUC in 16 patients (13%). During follow-up period (median 12.1 months), 101 patients died (2-year OS rate, 32%). Patients with elevated GGT at the diagnosis of aUC had a significantly poorer prognosis than those with normal GGT with respective 2-year OS rates of 0% and 37% (P < 0.001). On multivariate analysis, elevated GGT was a significant and independent risk factor for shorter OS (hazard ratio, HR = 2.97; P < 0.001) as were poorer Karnofsky performance status (HR = 3.47; P < 0.001), elevated lactate dehydrogenase (HR = 1.86; P = 0.033), advanced age (HR = 1.82; P = 0.013), elevated neutrophil-to-lymphocyte ratio (HR = 1.80; P = 0.015), elevated C-reactive protein (HR = 1.73; P = 0.018), the absence of systemic chemotherapy (HR = 1.71; P = 0.035), and primary site of upper urinary tract (HR = 1.71; P = 0.014) in descending order by HR. The prognostic significance of elevated GGT was also observed in a subset of 101 patients who had been diagnosed with aUC at their first presentation. CONCLUSION:The present study for the first time demonstrated that elevated serum GGT was an independent adverse prognostic factor in aUC patients.

The prospective evidence for the associations of gamma glutamyltransferase (GGT) and alanine aminotransferase (ALT) with risk of cancer in the general population is uncertain. We conducted a systematic review and meta-analysis of published prospective observational studies evaluating the associations of baseline levels of GGT and ALT with risk of overall (incidence and/or mortality) and site-specific cancers. Relevant studies were identified in a literature search of MEDLINE, EMBASE, Web of Science, reference lists of relevant studies to April 2014 and email contact with investigators. Study specific relative risks (RRs) were meta-analyzed using random effects models. Fourteen cohort studies with data on 1.79 million participants and 57,534 cancer outcomes were included. Comparing top versus bottom thirds of baseline circulating GGT levels, pooled RRs (95% confidence intervals) were 1.32 (1.15-1.52) for overall cancer, 1.09 (0.95-1.24) for cancers of the breast and female genital organs, 1.09 (1.02-1.16) for cancers of male genital organs, 1.94 (1.35-2.79) for cancers of digestive organs and 1.33 (0.94-1.89) for cancers of respiratory and intrathoracic organs. For ALT, corresponding RRs for overall cancer were 0.96 (0.94-0.99) and 1.65 (1.52-1.79) in European and Asian populations, respectively. There was an increased risk of cancers of the digestive organs 2.44 (1.23-4.84). The pooled RR for overall cancer per 5 U/L increment in GGT levels was 1.04 (1.03-1.05). Available observational data indicate a positive log-linear association of GGT levels with overall cancer risk. The positive association was generally evident for site-specific cancers. There are geographical variations in the association of ALT and overall cancer.

AIM:Biomarkers have been utilized for prognosis in colorectal cancer; however, relatively few have been identified. We compared the prognostic value of serum alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT) with carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) in patients with metastatic colorectal cancer (mCRC). METHOD:Blood samples were collected from 239 patients with mCRC presenting between 2005 and 2010 in the Sun Yat-sen University Cancer Center. RESULTS:CEA (P < 0.001), CA19-9 (P < 0.001), GGT (P < 0.001), ALP (P < 0.001) and LDH (P = 0.001) were statistically significant prognostic factors of overall survival (OS). CEA (P = 0.002) and GGT (P = 0.021) were validated as independent predictors. On univariate analysis, CEA (P = 0.003), CA19-9 (P = 0.006), GGT (P < 0.001) and ALP (P = 0.001) were statistically significant predictive factors of progression-free survival (PFS) in patients having first-line chemotherapy. CEA (P = 0.011) and GGT (P = 0.027) were independent predictors. GGT (P = 0.001), ALP (P = 0.016) and LDH (P = 0.039) levels were correlated with the tumour response rate assessed by CT, whilst CEA (P = 0.724) and CA19-9 (P = 0.822) were not. There was a statistically significant difference in OS (P < 0.001) and PFS (P < 0.001) among patients who had elevations of both CEA and GGT compared with those in whom only one or neither was elevated. CONCLUSION:Among GGT, LDH and ALP, only GGT plays an independent role with CEA in predicting OS and PFS in mCRC. When coupled with CEA, GGT may lead to improved prognostic predictors.

Serum gamma-glutamyltransferase (GGT) is thought to derive from the liver, but its values predict morbidity and mortality for several diseases, such as cardiac infarction, stroke, diabetes, renal failure and cancer. We assessed total GGT and its fractions in the culture supernatants of human cell lines (melanoma, prostate cancer, bronchial epithelium) by gel filtration chromatography. We also compared the GGT elution profile in plasma and the corresponding very-low-density lipoprotein (VLDL) fraction. All the cell lines tested released soluble GGT whose activity increased in parallel with the cell growth. Released GGT presented a molecular weight of 2000 kDa, identical to the b-GGT fraction of human plasma and corresponding to that of VLDL. But ultracentrifugation studies showed that b-GGT had a higher density than VLDL. The b-GGT present in human plasma can be produced by tissues other than the liver, thus explaining the increase of serum GGT observed in diseases of other organs.

BACKGROUND:The association between elevated γ-glutamyltransferase (GGT) at a certain point and incident cancer has been suggested; however, no study has evaluated the association between repeatedly elevated GGT and cancer incidence. AIM:To investigate the effects of repeatedly elevated GGT on the incidence of digestive cancers. METHODS:Participants who had undergone health screening from 2009 to 2012 and 4 consecutive previous examinations were enrolled. GGT points were calculated as the number of times participants met the criteria of quartile 4 of GGT in four serial measurements (0-4 points). Multivariable Cox proportional hazard regression models were applied. RESULTS:In total, 3559109 participants were included; among them, 43574 digestive cancers developed during a median of 6.8 years of follow-up. The incidence of total digestive cancers increased in a dose-response manner in men [adjusted hazard ratio (aHR) compared with those with 0 GGT points = 1.28 and 95% confidence interval (CI) = 1.24-1.33 in those with 1 point; aHR = 1.40 and 95%CI = 1.35-1.46 in those with 2 points; aHR = 1.52 and 95%CI = 1.46-1.58 in those with 3 points; aHR = 1.88 and 95%CI = 1.83-1.94 in those with 4 points; for trend < 0.001]. This trend was more prominent in men than in women and those with healthy habits (no smoking, no alcohol consumption, and a low body mass index) than in those with unhealthy habits. CONCLUSION:Repeatedly elevated GGT levels were associated with an increased risk of incident digestive cancer in a dose-responsive manner, particularly in men and those with healthy habits. Repeated GGT measurements may be a good biomarker of incident digestive cancer and could help physicians identify high-risk populations.

BACKGROUND:Gastric Cancer is one of the most lethal malignancies worldwide. Gamma-glutamyl transpeptidase (GGT) is an enzyme mainly involved in cellular glutathione homeostasis. We aim to explore the clinical value of GGT in gastric cancer. RESULTS:Among 322 patients enrolled, 65/82 patients were determined as GGT positive in serum/tumor, respectively. High tumor GGT expression is significantly associated with lymph node metastasis, histological subtype, and Her2 expression. Kaplan-Meier curve shows that high tumor GGT patients have shorter overall survival (P log-rank=0.001) and progress-free survival (P log-rank =0.001). Patients with both high tumor and serum GGT have the poorest prognosis. The multivariable Cox analysis shows that the hazard ratio of overall survival for high tumor GGT is 1.69 (95% CI 1.19-2.37). High serum GGT is a poor prognostic factor in adjuvant chemotherapy hazard ratio=2.18, 95%CI (1.15-4.47). These findings were further validated in six online datasets. Gene Sets Enrichment Analysis showed that GGT promotes cancer progression through EMT, KRAS, SRC and PKCA pathways. METHODS:Tumor GGT and serum GGT levels were evaluated with immuno-histochemistry staining and enzymatic assay, respectively. Kaplan-Meier curve and Cox regression model were used to test the association between GGT and gastric cancer prognosis. Independent datasets from Gene Expression Omnibus and Gene Sets Enrichment Analysis were applied to validate the findings and explore the potential mechanisms. CONCLUSION:Both tumor GGT and serum GGT are poor prognostic factors in gastric cancer. Patients with high tumor and serum GGT levels require more intense treatment and follow-up.

Increased circulating serum gamma-glutamyltransferase (GGT) has been linked with an increased risk of chronic disease outcomes, including overall and several site-specific cancers. However, the relationship of GGT with prostate cancer risk is uncertain. We aimed to assess the prospective association of GGT with risk of prostate cancer. Serum GGT activity was assessed at baseline in the Finnish Kuopio Ischemic Heart Disease prospective cohort of 2,390 men aged 42-61 years without a history of cancer at baseline. We corrected for within-person variability in GGT values using data from repeat measurements taken several years apart. During a median follow-up of 24.6 years, 230 cases of prostate cancer occurred. The age-adjusted regression dilution ratio for log GGT was 0.69 [95% confidence interval (CI): 0.63-0.74]. Serum GGT was nonlinearly associated with risk of prostate cancer. In age-adjusted Cox regression analysis, the hazard ratio (95% CIs) for prostate cancer in a comparison of the top quartile versus bottom quartiles 1-3 of GGT values was 1.43 (1.07 to 1.93; p = 0.017), which persisted on adjustment for several established cancer risk factors 1.46 (1.06 to 2.02; p = 0.020). The association remained unchanged on further adjustment for total energy intake, socioeconomic status, physical activity and C-reactive protein. The association did not importantly vary across several clinical subgroups. GGT is positively and independently associated with future risk of prostate cancer in a middle-aged Finnish male population over long-term follow-up. Further research is needed to understand the mechanistic pathways involved and if GGT may have potential relevance in prostate cancer prevention.

BACKGROUND:Serum AFP levels are typically elevated in less than 50% of hepatocellular cancer (HCC) patients. Gamma-glutamyl transpeptidase (GGT) levels have been suggested to be a potentially useful HCC biomarker. AIMS:To assess in a cohort of prospectively evaluated HCC patients who underwent liver transplant and whose survival was known; the occurrence, prognosis, and clinical characteristics of patients with elevated serum GGT levels. RESULTS:Serum GGT levels were found to be elevated in a higher proportion in patients with either small or large HCC than alpha-fetoprotein (AFP) levels, and were significantly related to prognosis in patients with large size HCCs. There was no clear correlation between GGT and AFP levels, likely reflecting different HCC characteristics or HCC cell lineages associated with these two markers. Furthermore, elevated GGT was found in 24% of low-AFP patients with small tumors and 46% with large tumors. Elevated GGT levels were also significantly associated with microvascular invasion and tumor diameter. CONCLUSIONS:Elevated serum GGT levels were associated with HCC size and worse survival, and were unrelated to AFP levels. GGT may be a useful prognostic tumor marker, especially for low-AFP HCC patients.

BACKGROUND:Although elevated serum gamma-glutamyltransferase (GGT) is a known indicator of increased risk of several cancers, the clinical value of repeated measurements of GGT has not been determined. Therefore, we aimed to investigate whether repeatedly elevated serum GGT levels are associated with the risk of respiratory cancer incidence. METHODS:We included participants who had undergone the Korean Health screening four times during 2009-2012 and had previously undergone four consecutive examinations. Those who were diagnosed with respiratory cancer before the date of examination were excluded. The participants obtained one GGT point if their GGT levels were in the highest quartile (the quartile 4 group). We analyzed the association between GGT points and respiratory cancer incidence by Cox proportional hazard models. RESULTS:During mean follow-up of 6.39 ± 1.2 years, 3,559,109 participants were enrolled. Of them, 8,944 (0.34%) men and 1,484 (0.14%) women were newly diagnosed with respiratory cancer. In multivariate analysis adjusted for confounding factors, male participants with 4 GGT points had a significantly higher hazards of developing respiratory cancer than those with 0 GGT points (hazard ratio [HR]: 1.39; 95% confidence interval [CI]: 1.31-1.48). Among female, participants with the highest points of GGT also had sixfold increased risk of developing laryngeal cancer. However, no significant association was observed between GGT points and lung cancer incidence among women (HR: 0.95; 95% CI: 0.81-1.11). CONCLUSION:Repeatedly elevated serum levels of GGT were associated with a higher risk of respiratory cancer incidence, especially in men. This finding suggests that physicians can identify a person with a higher risk of respiratory cancer through a simple repeated measurement of GGT.

γ-Glutamyltransferase (GGT), a membrane-bound enzyme, contributes to the metabolism of glutathione (GSH), which plays a critical physiological role in protecting cells against oxidative stress. GGT has been proposed as a biomarker of carcinogenesis and tumor progression given that GGT activity is important during both the promotion and invasion phases in cancer cells. Moreover, GGT expression is reportedly related to drug-resistance possibly because a wide range of drugs are conjugated with GSH, the availability of which is influenced by GGT activity. While serum GGT activity is commonly used as a quick, inexpensive, yet reliable means of assessing liver function, recent epidemiological studies have shown that it may also be an indicator of an increased risk of prostate cancer development. Moreover, elevated serum GGT is reportedly an adverse prognostic predictor in patients with urologic neoplasms, including renal cell carcinoma, prostate cancer, and urothelial carcinoma, although the background mechanisms have still not been well-characterized. The present review article summarizes the possible role of GGT in cancer cells and focuses on evidence evaluation through a systematic review of the latest literature on the prognostic role of serum GGT in patients with genitourinary cancer.

Polycation-based delivery presents a major method for non-viral gene therapy. However, the disadvantages of cationic vectors are their tendencies to be captured and eliminated by the reticuloendothelial system due to their excessive positive charges and nonspecific interaction with normal cells that leads to adverse effects. PEGylation was applied to solve these major problems. Yet, PEG chains can severely compromise cellular uptake and yield unsatisfying efficiency resulting in a so-called PEG dilemma. We developed a γ-PGA-based GGT-targeting and surface camouflage strategy by constructing a ternary complex system via a layer-by-layer self-assembly method. The biodegradable polyanion γ-PGA could protect the PEI/pDNA complexes from interaction with the body fluid components; however, in endosome, the polyanion facilitated the intracellular release of PEI/pDNA. The γ-PGA/PEI/pDNA nanoparticles possessed a markedly improved serum-tolerant capability. More importantly, γ-PGA interacts with the tumor-associated γ-glutamyl transpeptidase (GGT) that can mediate endocytosis of the nanoparticles. With pTRAIL as the therapeutic gene, the γ-PGA/PEI/pTRAIL nanoparticles effectively inhibited tumor cell proliferation by inducing cell apoptosis and arresting cell cycles. The in vivo results displayed effective suppression of tumor growth, and high treatment efficacy in the mice bearing cervical tumor. The γ-PGA-based GGT-targeting and surface camouflage strategy is a potential method for improved gene delivery and cancer therapy.

OBJECTIVE:This study aimed to determine the association of serum GGT levels with the risk of developing endometrial cancer. Women's obesity and menopausal status were also taken into account in our analysis. METHODS:We used a nationwide cohort to examine the association between serum GGT levels and endometrial cancer development in Korean women. Data were retrieved from the Korean National Health Insurance Service (NHIS) healthcare system. Women aged over 19 years who participated in the Korea National Health Screening Examination in 2009 and were not diagnosed with endometrial cancer 1-year post-examination were included in our study (n = 2,736,588). RESULTS:Obese (BMI, ≥25 kg/m) women with increased GGT levels were at high risk of endometrial cancer (HR = 1.415, 95% CI: 1.236-1.621). Interestingly, in pre-menopausal women, high GGT level (Q4) was associated with the increased endometrial cancer risk only for obese women (HR = 1.482, 95% CI: 1.205-1.821). In post-menopausal women, only a high GGT level (Q4) was also associated with the increased cancer risk for obese women (HR = 1.313, 95% CI: 1.096-1.573). We observed a significant association between high GGT levels and increased risk of endometrial cancer in pre-menopausal women with abdominal obesity (WC, ≥85 cm) (HR = 1.647, 95% CI: 1.218-2.227). CONCLUSIONS:Increased GGT level is an independent risk factor of endometrial cancer, especially for post-menopausal women and obese pre-menopausal women. These results may suggest that serum GGT levels might be useful in the risk stratification of endometrial cancer. Adopting a healthy lifestyle for lowering serum GGT level is warranted, especially for women with a higher risk of developing endometrial cancer.

BACKGROUND:The incidence of breast cancer has been gradually increasing in Korea. Recently, the elevated level of serum gamma-glutamyltransferase (GGT) has emerged to be associated with the development and progression of some malignancies. This study aimed to determine the effect of serum GGT levels on the risk of developing breast cancer in Korean women. METHODS:We used National Health Insurance Service Health Checkup data to examine the association between serum GGT levels and breast cancer development in Korean women. Women aged 40 years or older who participated in the Korean National Health Screening Examination between January 2009 and December 2009 and who did not develop any cancer within 1-year post examination were included in this analysis (n = 3,109,506). Cox proportional hazard regression analysis was conducted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS:Overall, an elevated serum GGT level was associated with the increased risk of developing breast cancer; compared to the Q1 group, the Q4 group showed a significantly increased breast cancer risk (HR: 1.120,95% CI: 1.08-1.162). Such a relationship was stronger in post-menopausal women than pre-menopausal women (HR: 1.173, 95% CI: 1.107-1.243; HR: 1.070, 95% CI:1.019-1.124). Women with a high GGT level (Q4) were also at an increased risk of developing carcinoma (CIS) (HR: 1.114, 95% CI: 1.04-1.192). In post-menopausal women, the Q4 group also exhibited higher CIS risk (HR: 1.266, 95% CI: 1.132-1.416). However, no significant difference in the risk of developing CIS was observed between the Q1 and Q4 groups in pre-menopausal women. Further analysis revealed that obese, post-menopausal women with a high GGT level (Q4) were associated with an increased risk of developing breast cancer (HR: 1.214, 95% CI: 1.125-1.31) and CIS (HR: 1.348, 95% CI: 1.159-1.569). CONCLUSIONS:Our study results demonstrate that increased serum GGT level is a risk factor for developing breast cancer. The post-menopausal women group with obesity and elevated serum GGT level showed the highest incidence of breast cancer. Thus, serum GGT concentration could be a novel and potential risk factor for breast cancer. Further validation in different ethnic groups would be warranted.

BACKGROUND:Accumulating evidence suggests that Gamma-glutamyltransferase (GGT) may be involved in cancer occurrence and progression. However, the prognostic role of serum GGT in pancreatic cancer (PC) survival lacks adequate evaluation. In this study, we aimed to analyze the association between serum GGT measured at diagnosis and overall survival (OS) in patients with metastatic PC. METHODS:We identified 320 patients with histopathologically confirmed metastatic pancreatic ductal adenocarcinoma (PDAC) diagnosed during 2015 and 2016 at a specialized cancer hospital in southwestern China. Univariate and multivariate Cox proportional-hazards models were used to determine associations between serum GGT and OS in metastatic PDAC. RESULTS:Controlled for possible confounding factors, serum GGT was significantly associated with OS: serum GGT > 48 U/L yielded a hazard ratio of 1.53 (95% CI: 1.19-1.97) for mortality risk. A significant dose-response association between serum GGT and OS was also observed. Subgroup analysis showed a possible interaction between GGT and blood glucose level. CONCLUSION:Serum GGT could be a potential indicator of survival in metastatic PDAC patients. Underlying mechanisms for this association should be investigated.

: Liver function is an important prognostic factor for patients with hepatocellular carcinoma. The purpose of this study was to develop and validate a nomogram integrating the albumin-bilirubin (ALBI) and serum γ-glutamyl transpeptidase (GGT) level to predict postoperative overall survival (OS) and disease-free survival (DFS) of hepatocellular carcinoma (HCC). : The effect of combined of ALBI and GGT on HCC prognosis was investigated using univariate and multivariate Cox analyses. The nomogram for OS and DFS were developed, respectively, and their predictive ability was compared with other conventional staging systems, including the American Joint Commission on Cancer (AJCC), Barcelona Clinic Liver Cancer (BCLC) and the Cancer of the Liver Italian Program (CLIP). : Combined ALBI and GGT was highly associated with OS (<0.001) and DFS (<0.001) of HCC patients treated with hepatic resection. In addition, the C-index of the OS (0.706±0.034) or DFS (0.674±0.032) nomogram in the training cohort was larger than AJCC, BCLC and CLIP. The Akaike information criterion (AICs) of the OS (2178.405) or DFS (2961.018) nomogram in the training cohort was smaller than above staging systems. The results suggested that the OS or DFS nomogram was the most powerful model to predict HCC prognosis. The similar trend was observed in the validation cohort. : The novel nomogram integrating ALBI and GGT was highly associated with OS and DFS of postoperative HCC patients.

Having long been regarded as just a member in the cellular antioxidant systems, as well as a clinical biomarker of hepatobiliary diseases and alcohol abuse, gamma-glutamyltransferase (GGT) enzyme activity has been highlighted by more recent research as a critical factor in modulation of redox equilibria within the cell and in its surroundings. Moreover, due to the prooxidant reactions which can originate during its metabolic function in selected conditions, experimental and clinical studies are increasingly involving GGT in the pathogenesis of several important disease conditions, such as atherosclerosis, cardiovascular diseases, cancer, lung inflammation, neuroinflammation and bone disorders. The present article is an overview of the laboratory findings that have prompted an evolution in interpretation of the significance of GGT in human pathophysiology.

BACKGROUND:Carbohydrate antigen 19-9 (CA19-9) has been reported as the most significant survival predictor of patients with pancreatic ductal adenocarcinoma (PDAC). However, the elevation of CA19-9 could interfere with obstructive jaundice and the predictive value of CA19-9 in PDAC patients with jaundice remains to be analyzed and elucidated to find possible adjustments. OBJECTIVE:To evaluate the predictability of preoperative CA19-9 and its adjustments for the overall survival (OS) of PDAC patients by analyzing the relationship between preoperative serum CA19-9 and total bilirubin (TBIL). METHODS:A total of 563 consecutive patients who underwent surgery for primary pancreatic adenocarcinoma in our center between January 2015 and September 2018 were retrospectively reviewed. Clinicopathologic information was collected and preoperative parameters such as CA19-9, CEA, TBIL, γ-GGT, AST, ALT, and ALP were recorded as well as overall survival rates, which began from the date of operation to that of death or the last follow-up. Kaplan-Meier survival curves with log-rank test and Cox regression models were applied using SPSS and the survival and survminer packages in R software. RESULTS:Using 39/390/1000 as the cut-off values for preoperative serum CA19-9, significant capability of OS stratification was found in the total cohort (p < 0.001, MST = 29.7/19.1/15.2/12.1 months) and patients with TBIL <102.6 μmol/L (p < 0.001, MST = 32.2/19.6/15.0/11.2 months). However, in the subgroup of TBIL≥102.6 μmol/L, this classification method was replaced by the combined scoring of CA19-9/AST and CA19-9/γ-GGT. CONCLUSIONS:As an independent predictor of overall survival of PDAC patients, preoperative serum CA19-9 is defective in survival stratification when TBIL≥102.6 μmol/L but a positive survival prognosis could be achieved with the application of combined preoperative CA19-9/AST and CA19-9/γ-GGT.

AIMS:Increasing evidence suggests that the serum-gamma-glutamyltransferase (GGT) might correlate with tumour development and growth rates in various human cancer types. Thus, we decided to investigate the potential prognostic impact of the preoperatively assessed serum-GGT in a European cohort of patients with non-metastatic renal cell carcinoma (RCC). METHODS:Clinicopathological data from 700 consecutive patients with non-metastatic RCC, operated between 2000 and 2010 at a single tertiary academic centre, were evaluated retrospectively. Preoperative serum-GGT was assessed 1 day before surgery. Patients were categorised using a serum-GGT cut-off value of 40 U/L according to a calculation by receiver operating curve analysis. Patients' cancer-specific survival (CSS), metastasis-free survival (MFS), as well as overall survival (OS) were assessed using the Kaplan-Meier method and Cox proportional models. RESULTS:In univariate analysis, an elevated preoperative serum-GGT level (<40 U/L vs ≥40 U/L) was statistically significantly associated with a shorter MFS (HR=1.517, 95% CI 1.047 to 2.197, p=0.027). In multivariate analyses, pathological T-Stage (pT-1 vs pT-2-4, HR=2.065, 95% CI 1.665 to 2.560), tumour grade (G-1+G-2 vs G-3+G-4, HR=1.671, 95% CI 1.261 to 2.213), as well as the presence of histological tumour necrosis (No vs Yes, HR=2.031, 95% CI 1.355 to 3.046) were independent predictors of MFS in patients with RCC, whereas the preoperative serum-GGT failed to reach independent predictor status (<40 U/L vs ≥40 U/L, HR=1.156, 95% CI 0.791 to 1.690). No prognostic role for GGT in OS or CSS could be identified. CONCLUSIONS:In the cohort studied, patients with an elevated (≥40 U/L) preoperative serum-GGT had a subsequently shorter MFS only in univariate analysis. In contrast to previous studies, our data failed to demonstrate preoperatively assessed serum-GGT as an independent prognostic factor in patients with non-metastatic RCC.

OBJECTIVE:This study aims to explore the rule of changes in serum GGT activity, as well as GGT/ALT and AST/ALT ratios, in primary hepatic carcinoma (PHC) patients with different alpha-fetal protein (AFP) levels. METHODS:GGT, AST and ALT were detected in 370 PHC patients with positive HBs-Ag using a automatic biochemical analyzer, and AFP was detected using a Roche E170 modular analytics immunoassay analyzer. GGT level, as well as AST/ALT and GGT/ALT, ratios were compared among PHC patients with different AFP levels. RESULTS:As shown in Table 1, GGT levels were 109.59 ± 111.06, 151.13 ± 190.43, 135.86 ± 107.62, 151.36 ± 176.59 and 172.58 ± 188.84, respectively, in the groups of primary PHC patients with AFP levels of ⩽ 10, 10-100, 100-200, 200-400 and ⩾ 400 ng/ml; and the differences among these groups were not statistically significant (P> 0.05). AST/ALT ratios were 1.55 ± 1.02, 1.30 ± 0.81, 2.02 ± 1.89, 2.12 ± 1.11 and 1.73 ± 1.25, respectively; and the differences among these groups were not statistically significant (P> 0.05). GGT/ALT ratios were 3.43 ± 3.12, 3.57 ± 5.70, 3.57 ± 2.94, 3.89 ± 4.58 and 3.43 ± 3.61, respectively; and the differences among these groups were not statistically significant (P> 0.05). CONCLUSION:For patients with chronic hepatitis B and cirrhosis after hepatitis B, no matter how AFP level is, when liver function report reveals increased GGT, AST/ALT > 1 and GGT/ALT > 1 (that is, AST > ALT and GGT > ALT), even if AFP is negative, we should also be alert to the existence of PHC.

γ-Glutamyltranspeptidase (GGT) is overexpressed in several types of cancer. Existing GGT-targeting fluorescence probes can image these cancers, but the fluorescent hydrolysis product leaks from the target cancer cells during prolonged incubation or fixation. Here, we present a functionalized fluorescence probe for GGT, 4-CH F-HMDiEtR-gGlu, which is designed to generate an azaquinone methide intermediate during activation by GGT; this intermediate reacts with intracellular nucleophiles to generate a fluorescent adduct that is trapped inside the cells, without loss of the target enzyme activity. Application of the probe to patient-derived xenograft (PDX) mice enabled in vivo cancer imaging for a prolonged period and was also compatible with fixation and immunostaining of the cancer tissue.

Abnormal expression of γ-glutamyltranspeptidase (GGT) in living organisms is closely associated with tumorigenesis. However, few reported fluorescence probes can specifically respond to abnormal concentration of GGT. Here, by functionalizing triarylboron moiety with three GGT-specific substrate (GSH) units, a novel fluorescence probe, TAB-3-GSH, was developed for detecting GGT. The results showed that TAB-3-GSH selectively responds to abnormally high levels of GGT (100-1000 U/L) rather than to normal GGT levels (<100 U/L) with ratiometric readout, since the amide linkage can be further hydrolyzed under high GGT levels. TAB-3-GSH was also capable of differentiating GGT-overexpressing ovarian cancer cells from normal cells, because of an improvement in the probe's cell membrane permeability upon reaction with GGT. Moreover, the probe could achieve selective imaging of SKOV-3 tumor site in xenograft mice model. Thus, TAB-3-GSH is a promising probe for tumor targeting in vivo.

Collagen type X alpha 1 (COL10A1) is a member of the collagen family and the main matrix component. However, COL10A1 expression and prognosis relationship remains unclear in gastric cancer (GC). Through the analysis of database of Oncomine, the Cancer Genome Atlas (TCGA) as well as the Gene Expression Omnibus (GEO), in contrast to the tissue of normal gastric, COL10A1 in gastric cancer, had been upregulated. The high expression of COL10A1 was obviously related to T stage ( = 0.025) and lymph node metastasis ( = 0.025). It has been illustrated by the analysis of logistic regression that COL10A1's heightened expression in gastric cancer had been essentially linked with pathological stage, tumor differentiation, and T classification. The Kaplan-Meier curve in the Kaplan-Meier plotter database ( = 0.0371) and GSE84437 ( = 0.002) indicate that patients with high COL10A1 expression possess poor prognosis, specifically GC patients with lymph node metastasis have it. TCGA's Multivariate analysis ( = 0.025) and GSE84437 dataset ( = 0.034) show that high expression COL10A1 is a key independent predictor of poor overall survival. Searching KEGG pathway enrichment by GSEA, the results suggested that 29 pathways were enriched. qRT-PCR technique was used for verification of the COL10A1's high expression in gastric cancer in contrast to the normal gastric tissues. In conclusion, COL10A1 is of great importance in predicting the survival rate of GC patients.

Gamma-glutamyltransferase (GGT) is an established marker for proliferative/apoptotic balance and has been associated with cancer risk and prognosis. The aim of this study was to evaluate the value of pre-treatment GGT serum levels as prognostic biomarker in patients with primary uterine leiomyosarcoma (ULMS). Data of women with ULMS were extracted from a multi-center database. Pre-treatment GGT serum levels were measured and patients assigned to predefined GGT risk groups. GGT values were correlated with clinico-pathological parameters and univariate and multivariable survival analyses were performed. A total of 44 patients with ULMS were analyzed. Mean (SD) pre-therapeutic GGT serum level was 33.8 (39.8) U/L. In Figo Stage I versus II-IV mean (SD) GGT values were 28.8 (34.0) U/l and 43.5 (49.2) U/l, respectively (p = 0.25). Five-year overall survival (OS) rates in ULMS patients with normal low versus higher GGT levels were 70% and 37%, respectively (p = 0.043). Univariate and multivariable analyses revealed that higher GGT serum levels (p = 0.043, p = 0.005) and high histological grade (p = 0.029, p = 0.012) were independently associated with impaired OS, respectively. Higher pre-treatment GGT serum levels were independently associated with unfavorable prognosis in women with ULMS. Thus, GGT seems to be a useful novel biomarker in ULMS.

γ-Glutamyl transpeptidase (GGT) is an enzyme located on the surface of cellular membranes and involved in GSH metabolism and maintenance of redox homeostasis. High GGT expression on tumor cells is associated with increased cell proliferation and resistance against chemotherapy. GGT inhibitors evaluated so far in clinical trials are too toxic for human use. In this study, using enzyme kinetics analyses, we demonstrate that ovothiols, 5(π)-methyl thiohistidines of marine origin, act as noncompetitive inhibitors of GGT, with an apparent of 21 μm, when we fixed the concentrations of the donor substrate. We found that these compounds are more potent than the known GGT inhibitor 6-diazo-5-oxo-l-norleucine and are not toxic toward human embryonic cells. In particular, cellular process-specific fluorescence-based assays revealed that ovothiols induce a mixed cell-death phenotype of apoptosis and autophagy in GGT-overexpressing cell lines, including human liver cancer and chronic B leukemic cells. The findings of our study provide the basis for further development of 5-thiohistidines as therapeutics for GGT-positive tumors and highlight that GGT inhibition is involved in autophagy.

BACKGROUND:Cancer-associated fibroblasts (CAFs), one of the principal constituents of the tumor microenvironment, have a pivotal role in tumor progression. Dysregulation of microRNAs (miRNAs) in CAFs contributes to the tumor-promoting ability of CAFs. However, the mechanism underlying the involvement of miRNAs in CAFs of gastric cancer (GC) is not fully understood. This study aimed to explore the effects of miRNA-214 in CAFs on GC migration and invasion. METHODS:The primary CAFs and corresponding normal fibroblasts (NFs) were isolated. Cell counting kit-8, EdU cell proliferation staining and Transwell assays were used to determine the role of miRNA-214 in GC progression. Real-time polymerase chain reaction, Western blot analysis, and dual-luciferase reporter assay were performed to verify the target genes of miRNA-214. Immunofluorescence and Western blot analysis were applied to detect the expression of epithelial-mesenchymal transition (EMT) markers. Immunohistochemistry and in situ hybridization were implemented to analyze the fibroblast growth factor 9 (FGF9) and miRNA-214 expression in human GC tissues, respectively. Finally, to assess its prognostic relevance, Kaplan-Meier survival analysis was conducted. RESULTS:MiRNA-214 was significantly downregulated in CAFs of GC compared with NFs. The upregulation of miRNA-214 in CAFs inhibited GC cell migration and invasion in vitro but failed to affect proliferation. Moreover, GC cells cultured with conditioned medium from CAFs transfected with miR-214 mimic showed increased expression of E-cadherin and decreased expression of Vimentin, N-cadherin and Snail, indicating the suppression of EMT of GC cells. Furthermore, FGF9 was proved to be a direct target gene of miR-214. The expression of FGF9 was higher in CAFs than that in tumor cells not only in primary tumor but also in lymph node metastatic sites (30.0% vs 11.9%, P < 0.01 and 32.1% vs 12.3%, P < 0.01, respectively). Abnormal expression of FGF9 in CAFs of lymph node metastatic sites was significantly associated with poor prognosis in patients with GC (P < 0.05). CONCLUSIONS:This study showed that miR-214 inhibited the tumor-promoting effect of CAFs on GC through targeting FGF9 in CAFs and regulating the EMT process in GC cells, suggesting miRNA-214/FGF9 in CAFs as a potential target for therapeutic approaches in GC.

Cancer-associated fibroblasts (CAFs) are principal constituents of the tumor microenvironment (TME) and play a critical role in tumor progression. The CXCL12/CXCR4 axis regulates multiple facets of the TME. The aim of this study was to determine the relationship between CXCL12 expression in CAFs and the malignant progression of gastric cancer (GC). In the GEO (Gene Expression Omnibus) database, we performed transcriptome analysis on paired gastric cancer RNA sequencing samples, and scRNA analysis was performed on advanced malignant GC samples from the scRNA sequencing data set. Fibroblast cells were co-cultured with GC cells, and invasion, migration, epithelial-mesenchymal transformation (EMT) were determined. After blocking the expression of fibroblast CXCL12, cells were co-cultured with a GC cell line. Detection of GC cell line invasion, migration, EMT and CXCR4, Wnt5a and β-Catenin expression levels was performed. Primary CAFs and gastric normal fibroblasts were isolated and CXCL12 mRNA and protein expression were determined. In addition, a cohort of 285 GC cases was established, protein expression was evaluated immunohistochemically, and prognostic results were analyzed. GC transcriptome analysis suggested that cytokine-cytokine receptor interaction and the Wnt signaling pathway in GC tissues were significantly up-regulated. scRNA analysis of advanced malignant GC samples showed that severe intestinal metaplasia (SIM) in GC specimens of different malignant grades had obvious fibroblast clusters compared to non-atrophic gastritis (NAG) and early gastric cancer (EGC). In the SIM group, fibroblast cluster, CXCL12, CXCR4, and Wnt5a were overexpressed. Co-culturing with fibroblast cells significantly increased the invasion, migration, and EMT of GC cells, and blocking CXCL12 in CAFs disturbed the expression of Wnt5a and β-catenin. In our cohort of GC patients, high CXCL12 expression in CAFs significantly correlated with histological grade (P = 0.012) and TNM stage (P = 0.014), as well as with poor overall survival (p = 0.0107). High expression of CXCL12 in CAFs in a GC microenvironment can affect the migration, invasion, and EMT of GC cells. Furthermore, it can cause poor prognosis in patients with GC.

Gastric cancer (GC) is one of the most commonly occurring cancers, and metabolism-related genes (MRGs) are associated with its development. Transcriptome data and the relevant clinical data were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases, and we identified 194 MRGs differentially expressed between GC and adjacent nontumor tissues. Through univariate Cox and lasso regression analyses we identified 13 potential prognostic differentially expressed MRGs (PDEMRGs). These PDEMRGs (CKMT2, ME1, GSTA2, ASAH1, GGT5, RDH12, NNMT, POLR1A, ACYP1, GLA, OPLAH, DCK, and POLD3) were used to build a Cox regression risk model to predict the prognosis of GC patients. Further univariate and multivariate Cox regression analyses showed that this model could serve as an independent prognostic parameter. Gene Set Enrichment Analysis showed significant enrichment pathways that could potentially contribute to pathogenesis. This model also revealed the probability of genetic alterations of PDEMRGs. We have thus identified a valuable metabolic model for predicting the prognosis of GC patients. The PDEMRGs in this model reflect the dysregulated metabolic microenvironment of GC and provide useful noninvasive biomarkers.

Despite the amazing progress in the treatment of gastric cancer (GC), it is still the third leading cause of cancer death in the world. This study explored the key genes that are related to the prognosis and pathogenesis of GC. Data from the cancer genome atlas (TCGA) and Oncomine were applied to evaluate the expression of cystatin 2 (CST2) in GC samples. Kaplan-Meier plotter was carried out to detect the overall survival of GC patients with different expression levels of CST2. Gene Set Enrichment Analysis (GSEA) was carried out to investigate the functions and pathways connected with CST2 expression. Quantitative real-time polymerase chain reaction (qPCR) and Western blot assays were used to assess CST2 expression. The biological properties of GC cells were assessed with the support of cell proliferation and Transwell assays. Important proteins involved in the regulation of CST2 in GC cell behaviors were evaluated by Western blot. Through analysis of the database, we found that CST2 expression was significantly upregulated in GC samples and actively related to GC patients' poor outcomes. Importantly, the analysis of GSEA showed that GST2 expression was closely connected with the proliferation and migration of cells, as well as the TGF-β1 signaling pathway. In addition, biological assays illustrated that over-expression of CST2 strengthened the activity and metastasis of GC cells. After the upregulation of CST2, the expression of cyclin D1, N-cadherin, vimentin, TGF-β1, and Smad4 increased, and E-cadherin expression decreased. Our findings revealed that over-expression of CST2 enhanced the growth, migration, and invasion of GC cells through modulating the epithelial-mesenchymal transition (EMT) and TGF-β1 signaling pathway, affording a possible biomarker for the treatment of GC.

Gamma-glutamyltransferase 5 (GGT5) is a member of the gamma-glutamyl transpeptidase gene family with the capacity of cleaving the gamma-glutamyl moiety of glutathione, but its role in cancer progression has never been revealed. In this study, we found that gene was highly expressed in cancer-associated fibroblasts (CAFs) in lung adenocarcinoma, predicting the unfavorable survival of patients with lung adenocarcinoma. Cell growth, foci formation and spheres formation analyses showed that cancer cell proliferation was attenuated under treatment with the conditioned media from GGT5-silenced CAFs. Moreover, high expression of GGT5 in CAFs enhanced the drug resistance of cancer cells by increasing intracellular glutathione and reducing the intracellular reactive oxygen species in cancer cells. In mouse xenograft model, we proved that targeting GGT5 with a small-molecule inhibitor GGsTop could inhibit tumor growth and increase the chemosensitivity of cancer cells. Taken together, our study illuminates that high level of GGT5 in CAFs contributes to cancer cell survival and drug resistance, indicating that GGT5 may be a promising therapeutic target in lung adenocarcinoma.

BACKGROUND:Localized to cell membrane, γ-glutamyl transferase (GGT) is a reliable marker for the evaluation of cell distress occurring in several pathological conditions including obesity, metabolic syndrome, and cancer. In particular, high GGT serum levels are associated with breast cancer incidence and progression. METHODS:The tissue expression of GGT1, the gene coding for GGT, was investigated in silico in a large case series of paired samples of breast cancer and adjacent histologically normal (HN) tissue, and in a collection of healthy breast tissues from reduction mammoplasty. The association of GGT1 with patient's body mass index (BMI), and the relationship between GGT1 and a panel of genes involved in apoptosis, IGF-1 signaling, or coding for adipokines and adipokine receptors were also investigated. RESULTS:GGT1 expression was significantly higher in tumor than in the adjacent HN tissue (P = 0.0002). Unexpectedly, the expression of GGT1 was inversely associated with BMI in normal and HN tissue, whereas no correlation was found in cancerous tissue. In all tissues, GGT1 correlated positively with TP53 and negatively with BCL2 and LEPR, whereas only in normal and HN tissue GGT1 correlated positively with IGF1R. The linear regression model, adjusted for BMI, showed no confounding effect on any correlation, except for the correlation of GGT1 with LEPR in normal tissue from healthy women. CONCLUSIONS:Even if present results provide interesting insights on the still elusive mechanism(s) underlying the association between obesity and epithelial cell proliferation, possibly promoting neoplastic transformation, such relationship deserves further investigation in other independent datasets.

Assays for gamma-glutamyl transferase (GGT1, EC 2.3.2.2) activity in blood are widely used in a clinical setting to measure tissue damage. The well-characterized GGT1 is an extracellular enzyme that is anchored to the plasma membrane of cells. There, it hydrolyzes and transfers gamma-glutamyl moieties from glutathione and other gamma-glutamyl compounds to acceptors. As such, it has a critical function in the metabolism of glutathione and in the conversion of the leukotriene LTC4 to LTD4. GGT deficiency in man is rare and for the few patients reported to date, mutations in GGT1 have not been described. These patients do secrete glutathione in urine and fail to metabolize LTC4. Earlier pre-genome investigations had indicated that besides GGT1, the human genome contains additional related genes or sequences. These sequences were given multiple different names, leading to inconsistencies and confusion. Here we systematically evaluated all human sequences related to GGT1 using genomic and cDNA database searches and identified thirteen genes belonging to the extended GGT family, of which at least six appear to be active. In collaboration with the HUGO Gene Nomenclature Committee (HGNC) we have designated possible active genes with nucleotide or amino acid sequence similarity to GGT1, as GGT5 (formerly GGL, GGTLA1/GGT-rel), GGT6 (formerly rat ggt6 homologue) and GGT7 (formerly GGTL3, GGT4). Two loci have the potential to encode only the light chain portion of GGT and have now been designated GGTLC1 (formerly GGTL6, GGTLA4) and GGTLC2. Of the five full-length genes, three lack of significant nucleotide sequence homology but have significant (GGT5, GGT7) or very limited (GGT6) amino acid similarity to GGT1 and belong to separate families. GGT6 and GGT7 have not yet been described, raising the possibility that leukotriene synthesis, glutathione metabolism or gamma-glutamyl transfer is regulated by their, as of yet uncharacterized, enzymatic activities. In view of the widespread clinical use of assays that measure gamma-glutamyl transfer activity, this would appear to be of significant interest.