Nicotinamide phosphoribosyltransferase (NAMPT) is a critical rate-limiting enzyme involved in NAD synthesis that has been shown to contribute to the progression of liver cancer. However, the potential role and mechanism of NAMPT in hepatitis B virus (HBV)-associated liver cancer remain unclear. The present study assessed the expression of NAMPT in HBV-positive and -negative liver cancer cells, and investigated whether HBV-induced NAMPT expression is dependent on HBV X protein (HBx). In addition, the role of NAMPT in HBV replication and transcription, and in HBV-mediated liver cancer cell growth was explored. The effects of NAMPT on the glycolytic pathway were also evaluated. Reverse transcription-quantitative PCR and western blotting results revealed that NAMPT expression levels were significantly higher in HBV-positive liver cancer cells than in HBV-negative liver cancer cells, and this effect was HBx-dependent. Moreover, the activation of NAMPT was demonstrated to be required for HBV replication and transcription. The NAMPT inhibitor FK866 repressed cell survival and promoted cell death in HBV-expressing liver cancer cells, and these effects were attenuated by nicotinamide mononucleotide. Furthermore, the inhibition of NAMPT was associated with decreased glucose uptake, decreased lactate production and decreased ATP levels in HBV-expressing liver cancer cells, indicating that NAMPT may promote the aerobic glycolysis. Collectively, these findings reveal a positive feedback loop in which HBV enhances NAMPT expression and the activation of NAMPT promotes HBV replication and HBV-mediated malignant cell growth in liver cancer. The present study highlights the important role of NAMPT in the regulation of aerobic glycolysis in HBV-mediated liver cancer, and suggests that NAMPT may be a promising treatment target for patients with HBV-associated liver cancer.

OBJECTIVE:The abnormal expression of fragile histidine triad (FHIT) gene has been frequently reported in a variety of epithelial malignancies including cervical carcinoma. Furthermore, in a recent study it was proposed that transcriptional inactivation of FHIT, as a consequence of aberrant 5'-CpG island methylation, plays an important role in the carcinogenesis of human cervical carcinoma. The authors sought to determine whether abnormal FHIT transcription occurs in human cervical carcinoma, and if so, whether this abnormal expression is associated with aberrant 5'-CpG island methylation. In addition, the clinical significance of FHIT inactivation was investigated in Korean women with cervical cancer. METHODS:To examine for abnormal transcripts of the FHIT gene, quantitative RT-PCR, genomic DNA-PCR and nonisotopic RT-PCR-SSCP analysis were performed using the standard method. The methylation status was determined by methylation specific PCR and bisulfite DNA sequencing. RESULTS:The FHIT gene was down-regulated in 15 of 58 (25.9%) cervical carcinomas. FHIT promoter hypermethylation was detected in 15 of 15 (100%) abnormally expression in cervical carcinomas. Bisulfite DNA sequencing confirmed these findings and a significant correlation was found between CpG site hypermethylation and low FHIT expression. However, no significant correlation was found between reduced FHIT expression and clinicopathological characteristics. CONCLUSION:In this study, FHIT inactivation in cervical cancer was found to be strongly correlated with 5'-CpG island hypermethylation rather than a genetic alteration. Furthermore, no significant relation was found between a lack of FHIT expression and the prognostic factors of cervical cancer in our Korean cohort.

OBJECTIVE:To correlate p16 positive cervical precancers of 388 consecutive patients from a single European center with the preceding clinical HPV-DNA and HPV E6/E7 mRNA screening test. METHOD:374/388 patients had a HSIL (CIN 2/3) and 14/388 AIS (6 pure and 8 combined AIS/HSIL). Lesional tissues of HSIL/AIS with negative Cobas and/or Aptima HPV tests underwent HPV genotyping with CHIPRON HPV 3.5 LCD-array. Selected cases were subjected to a cancer hot spot analysis. RESULTS:The Aptima test missed 10/388 (2.6%) and the Cobas test seven of 388 (1.8%) precancers associated HPV-HR. Both HPV tests were negative in 20/374 precancers (5.3%; 17 HSIL/CIN3, two HSIL/CIN2, one AIS). Due to insufficient DNA four of 20 double negative cases (three HSIL, one AIS) were not genotyped. In the remaining cases, two of 20 (10%) HSIL genotyping detected HR-HPV subtypes. 10/20 (50%) HSIL were associated with possibly carcinogenic and low risk HPV (four x HPV73, three x HPV 53, one x HPV 82, one x HPV 67 and one x HPV 6), all of which are not included in both HPV tests. Two of 20 (10%) HSIL were negative with all HPV tests; one of these HSIL had a somatic PIK3CA gene mutation and the other had a single nucleotide variant in the APC gene. Three of 20 HSIL (15%) were thin HSIL (≤9 cell layers thick). CONCLUSIONS:Possibly carcinogenic HPV subtypes not included in the clinical HPV tests may account for the small gap of missed HSIL in clinical HPV screening. True HPV negative HSIL are exceedingly rare. Expanding HPV testing to include more possibly carcinogenic HPV subtypes may further reduce cervical cancer.