Biological Effect of a Hybrid Anticancer Agent Based on Kinase and Histone Deacetylase Inhibitors on Triple-Negative (MDA-MB231) Breast Cancer Cells. Librizzi Mariangela,Spencer John,Luparello Claudio International journal of molecular sciences We examined the effects of the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) combined with the vascular endothelial growth factor receptor-1/2 inhibitor (3Z)-5-hydroxy-3-(1H-pyrrol-2-ylmethylidene)-2,3-dihydro-1H-indol-2-one on MDA-MB-231 breast cancer cells (triple-negative) in the form of both a cocktail of the separate compounds and a chemically synthesized hybrid (N-hydroxy-N'-[(3Z)-2-oxo-3-(1H-pyrrol-2-ylmethylidene)-2,3-dihydro-1H-indol-5-yl]octanediamide). Comparative flow cytometric and Western blot analyses were performed on cocktail- and hybrid-treated cells to evaluate cell cycle distribution, autophagy/apoptosis modulation, and mitochondrial metabolic state in order to understand the cellular basis of the cytotoxic effect. Cell cycle analysis showed a perturbation of the rate of progression through the cycle, with aspects of redistribution of cells over different cycle phases for the two treatments. In addition, the results suggest that the two distinct classes of compounds under investigation could induce cell death by different preferential pathways, i.e., autophagy inhibition (the cocktail) or apoptosis promotion (the hybrid), thus confirming the enhanced potential of the hybrid approach vs. the combination approach in finely tuning the biological activities of target cells and also showing the hybrid compound as an additional promising drug-like molecule for the prevention or therapy of "aggressive" breast carcinoma. 10.3390/ijms17081235
    Cytotoxic effects of Jay Amin hydroxamic acid (JAHA), a ferrocene-based class I histone deacetylase inhibitor, on triple-negative MDA-MB231 breast cancer cells. Librizzi Mariangela,Longo Alessandra,Chiarelli Roberto,Amin Jahanghir,Spencer John,Luparello Claudio Chemical research in toxicology The histone deacetylase inhibitors (HDACis) are a class of chemically heterogeneous anticancer agents of which suberoylanilide hydroxamic acid (SAHA) is a prototypical member. SAHA derivatives may be obtained by three-dimensional manipulation of SAHA aryl cap, such as the incorporation of a ferrocene unit like that present in Jay Amin hydroxamic acid (JAHA) and homo-JAHA [ Spencer , et al. ( 2011 ) ACS Med. Chem. Lett. 2 , 358 - 362 ]. These metal-based SAHA analogues have been tested for their cytotoxic activity toward triple-negative MDA-MB231 breast cancer cells. The results obtained indicate that of the two compounds tested, only JAHA was prominently active on breast cancer cells with an IC(50) of 8.45 μM at 72 h of treatment. Biological assays showed that exposure of MDA-MB231 cells to the HDACi resulted in cell cycle perturbation with an alteration of S phase entry and a delay at G(2)/M transition and in an early reactive oxygen species production followed by mitochondrial membrane potential (MMP) dissipation and autophagy inhibition. No annexin binding was observed after short- (5 h) and longer (24 and 48 h) term incubation with JAHA, thereby excluding the promotion of apoptosis by the HDACi. Although caution must be exercised in extrapolation of in vitro results to the in vivo situation for which research on animals and human trials are needed, nevertheless JAHA treatment possesses the potential for its development as an agent for prevention and/or therapy of "aggressive" breast carcinoma, thus prompting us to get more insight into the molecular basis of its antibreast cancer activity. 10.1021/tx300376h
    The Application of Non-Invasive Apoptosis Detection Sensor (NIADS) on Histone Deacetylation Inhibitor (HDACi)-Induced Breast Cancer Cell Death. Hsu Kai-Wen,Huang Chien-Yu,Tam Ka-Wai,Lin Chun-Yu,Huang Li-Chi,Lin Ching-Ling,Hsieh Wen-Shyang,Chi Wei-Ming,Chang Yu-Jia,Wei Po-Li,Chen Shou-Tung,Lee Chia-Hwa International journal of molecular sciences Breast cancer is the most common malignancy in women and the second leading cause of cancer death in women. Triple negative breast cancer (TNBC) subtype is a breast cancer subset without ER (estrogen receptor), PR (progesterone receptor) and HER2 (human epidermal growth factor receptor 2) expression, limiting treatment options and presenting a poorer survival rate. Thus, we investigated whether histone deacetylation inhibitor (HDACi) could be used as potential anti-cancer therapy on breast cancer cells. In this study, we found TNBC and HER2-enriched breast cancers are extremely sensitive to Panobinostat, Belinostat of HDACi via experiments of cell viability assay, apoptotic marker identification and flow cytometry measurement. On the other hand, we developed a bioluminescence-based live cell non-invasive apoptosis detection sensor (NIADS) detection system to evaluate the quantitative and kinetic analyses of apoptotic cell death by HDAC treatment on breast cancer cells. In addition, the use of HDACi may also contribute a synergic anti-cancer effect with co-treatment of chemotherapeutic agent such as doxorubicin on TNBC cells (MDA-MB-231), but not in breast normal epithelia cells (MCF-10A), providing therapeutic benefits against breast tumor in the clinic. 10.3390/ijms19020452
    Co-targeting poly(ADP-ribose) polymerase (PARP) and histone deacetylase (HDAC) in triple-negative breast cancer: Higher synergism in BRCA mutated cells. Marijon Hélène,Lee Dhong Hyun,Ding LingWen,Sun Haibo,Gery Sigal,de Gramont Aimery,Koeffler H Phillip Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie PURPOSE:Despite similarities with BRCA-mutated breast cancers, triple-negative breast cancers (TNBC) remain resistant to poly(ADP-ribose) polymerase (PARP) inhibitors as single agents. Histone deacetylase inhibitors (HDACi) can decrease expression of proteins involved in DNA repair. We thus hypothesized that a HDACi (suberoylanilide hydroxamic acid (SAHA) or belinostat) could sensitize TNBC to the PARP inhibitor olaparib. METHODS:Human TNBC cells were co-treated with olaparib and either SAHA or belinostat, and their effects on survival, proliferation, cell cycle, apoptosis and DNA repair pathways were evaluated. Subcutaneous xenografts were used to determine the effect of the combination treatment in vivo. RESULTS:HDACi and olaparib synergistically inhibited proliferation of a panel of 8 TNBC cell lines in vitro and in nude mice harboring TNBC xenografts in vivo. We noted a weaker synergism in PTEN-deficient TNBC cells and a stronger synergism in BRCA1-mutated TNBC cells. In the BRCA1-mutated cell line HCC-1937, we observed a drastic decrease in the expression of proteins involved in homologous recombination (HR), leading to a large imbalance of the ratio P-H2AX/RAD51. In BRCA1 wild type (wt) cell lines, effect of the combination treatment relied on DNA damage-induced cell cycle arrest followed by induction of apoptosis. CONCLUSION:In summary, these results provide a preclinical rationale to combine a HDACi with a PARP inhibitor to reduce HR efficiency in TNBC and sensitize these aggressive tumors to PARP inhibition. 10.1016/j.biopha.2018.01.045
    [Inhibition of Histone Deacetylases Reverses Epithelial-Mesenchymal Transition in Triple-Negative Breast Cancer Cells through a Slug Mediated Mechanism]. Rahimian A,Barati G,Mehrandish R,Mellati A A Molekuliarnaia biologiia High metastatic ability and poor clinical outcome are the most known clinical features of the triple-negative breast tumors. Given that the tumor cells undergoing epithelial-mesenchymal transition (EMT) often gain malignant and invasive features, we have investigated the possibility of EMT reversal in triple-negative breast cancer cells by targeting the epigenetic-modifying enzymatic complexes named histone deacetylases (HDACs) and examined the possible mechanism underlying the HDACs-based inversion in model MDA-MB-231 cells. Cells were treated with a maximal tolerable 200 nM concentrations of classical HDACs inhibitor Trichostatin A (TSA) for 48 h and afterwards the invasiveness and immigration of the cells were evaluated in TransWell Invasion Scratch Wound Healing assays. Then, in treated and control cells, quantitative real time-PCR reacions were performed for assessing the gene expression of EMT biomarkers E-cadherin, Vimentin and transcriptional factor Slug. After TSA treatment, the invasion and migration properties MDA-MB-231 cells significantly decreased, gene expression of E-cadherin was significantly up-regulated, while the levels of Slug and Vimentin encoding mRNAs were suppressed. We conclude that inhibition of HDACs in triple-negative breast cancer cells may lead to inversion of EMT and the decrease of invasiveness by down-regulating the gene expression of Slug. Since EMT is known as a pre-metastatic process, triple-negative breast tumors, the EMT reversal effects of HDACs inhibition may reduce tumor cell metastasis. 10.7868/S0026898418030102
    Suberoylanilide hydroxamic acid, an inhibitor of histone deacetylase, enhances radiosensitivity and suppresses lung metastasis in breast cancer in vitro and in vivo. Chiu Hui-Wen,Yeh Ya-Ling,Wang Yi-Ching,Huang Wei-Jan,Chen Yi-An,Chiou Yi-Shiou,Ho Sheng-Yow,Lin Pinpin,Wang Ying-Jan PloS one Triple-negative breast cancer (TNBC), defined by the absence of an estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression, is associated with an early recurrence of disease and poor outcome. Furthermore, the majority of deaths in breast cancer patients are from metastases instead of from primary tumors. In this study, MCF-7 (an estrogen receptor-positive human breast cancer cell line), MDA-MB-231 (a human TNBC cell line) and 4T1 (a mouse TNBC cell line) were used to investigate the anti-cancer effects of ionizing radiation (IR) combined with suberoylanilide hydroxamic acid (SAHA, an inhibitor of histone deacetylase (HDAC)) and to determine the underlying mechanisms of these effects in vitro and in vivo. We also evaluated the ability of SAHA to inhibit the metastasis of 4T1 cells. We found that IR combined with SAHA showed increased therapeutic efficacy when compared with either treatment alone in MCF-7, MDA-MB-231 and 4T1 cells. Moreover, the combined treatment enhanced DNA damage through the inhibition of DNA repair proteins. The combined treatment was induced primarily through autophagy and ER stress. In an orthotopic breast cancer mouse model, the combination treatment showed a greater inhibition of tumor growth. In addition, SAHA inhibited the migration and invasion abilities of 4T1 cells and inhibited breast cancer cell migration by inhibiting the activity of MMP-9. In an in vivo experimental metastasis mouse model, SAHA significantly inhibited lung metastasis. SAHA not only enhances radiosensitivity but also suppresses lung metastasis in breast cancer. These novel findings suggest that SAHA alone or combined with IR could serve as a potential therapeutic strategy for breast cancer. 10.1371/journal.pone.0076340
    A novel histone deacetylase inhibitor TMU-35435 enhances etoposide cytotoxicity through the proteasomal degradation of DNA-PKcs in triple-negative breast cancer. Wu Yuan-Hua,Hong Chi-Wei,Wang Yi-Ching,Huang Wei-Jan,Yeh Ya-Ling,Wang Bour-Jr,Wang Ying-Jan,Chiu Hui-Wen Cancer letters Triple-negative breast cancer (TNBC) treatment offers only limited benefits, and it is very relevant given the significant number of deaths that it causes. DNA repair pathways can enable tumor cells to survive DNA damage that is induced by chemotherapeutic or radiation treatments. Histone deacetylase inhibitors (HDACi) inhibited DNA repair proteins. However, the detailed mechanisms for this inhibition remain unclear. In the present study, we investigated whether a newly developed HDACi, TMU-35435, could enhance etoposide cytotoxicity by inhibiting DNA repair proteins in triple-negative breast cancer. We found synergistic cytotoxicity following treatment of 4T1 cells with etoposide and TMU-35435. Furthermore, TMU-35435 enhances etoposide-induced DNA damage by inhibiting the DNA repair pathway (non-homologous end joining, NHEJ). TMU-35435 suppresses the NHEJ pathway through the ubiquitination of DNA-dependent protein kinase catalytic subunit (DNA-PKcs). In addition, TMU-35435 ubiquitinated DNA-PKcs by inducing the interaction between RNF144A (an E3 ligase) and DNA-PKcs. The combined treatment induced apoptosis and autophagic cell death in 4T1 cells. In an orthotopic breast cancer model, combined treatment with TMU-35435 and etoposide showed anti-tumor growth through the increase of DNA damage and cell death. Taken together, our data suggest that TMU-35435 enhances etoposide cytotoxicity by regulating ubiquitin-proteasome system and inhibiting the DNA repair pathway in TNBC. 10.1016/j.canlet.2017.04.023
    Targeting triple-negative breast cancer cells with the histone deacetylase inhibitor panobinostat. Tate Chandra R,Rhodes Lyndsay V,Segar H Chris,Driver Jennifer L,Pounder F Nell,Burow Matthew E,Collins-Burow Bridgette M Breast cancer research : BCR INTRODUCTION:Of the more than one million global cases of breast cancer diagnosed each year, approximately fifteen percent are characterized as triple-negative, lacking the estrogen, progesterone, and Her2/neu receptors. Lack of effective therapies, younger age at onset, and early metastatic spread have contributed to the poor prognoses and outcomes associated with these malignancies. Here, we investigate the ability of the histone deacetylase inhibitor panobinostat (LBH589) to selectively target triple-negative breast cancer (TNBC) cell proliferation and survival in vitro and tumorigenesis in vivo. METHODS:TNBC cell lines MDA-MB-157, MDA-MB-231, MDA-MB-468, and BT-549 were treated with nanomolar (nM) quantities of panobinostat. Relevant histone acetylation was verified by flow cytometry and immunofluorescent imaging. Assays for trypan blue viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) proliferation, and DNA fragmentation were used to evaluate overall cellular toxicity. Changes in cell cycle progression were assessed with propidium iodide flow cytometry. Additionally, qPCR arrays were used to probe MDA-MB-231 cells for panobinostat-induced changes in cancer biomarkers and signaling pathways. Orthotopic MDA-MB-231 and BT-549 mouse xenograft models were used to assess the effects of panobinostat on tumorigenesis. Lastly, flow cytometry, ELISA, and immunohistochemical staining were applied to detect changes in cadherin-1, E-cadherin (CDH1) protein expression and the results paired with confocal microscopy in order to examine changes in cell morphology. RESULTS:Panobinostat treatment increased histone acetylation, decreased cell proliferation and survival, and blocked cell cycle progression at G2/M with a concurrent decrease in S phase in all TNBC cell lines. Treatment also resulted in apoptosis induction at 24 hours in all lines except the MDA-MB-468 cell line. MDA-MB-231 and BT-549 tumor formation was significantly inhibited by panobinostat (10 mg/kg/day) in mice. Additionally, panobinostat up-regulated CDH1 protein in vitro and in vivo and induced cell morphology changes in MDA-MB-231 cells consistent with reversal of the mesenchymal phenotype. CONCLUSIONS:This study revealed that panobinostat is overtly toxic to TNBC cells in vitro and decreases tumorigenesis in vivo. Additionally, treatment up-regulated anti-proliferative, tumor suppressor, and epithelial marker genes in MDA-MB-231 cells and initiated a partial reversal of the epithelial-to-mesenchymal transition. Our results demonstrate a potential therapeutic role of panobinostat in targeting aggressive triple-negative breast cancer cell types. 10.1186/bcr3192
    Histone Deacetylase Inhibitor-Induced Autophagy in Tumor Cells: Implications for p53. Mrakovcic Maria,Kleinheinz Johannes,Fröhlich Leopold F International journal of molecular sciences Autophagy is an essential process of the eukaryotic cell allowing degradation and recycling of dysfunctional cellular components in response to either physiological or pathological changes. Inhibition of autophagy in combination with chemotherapeutic treatment has emerged as a novel approach in cancer treatment leading to cell cycle arrest, differentiation, and apoptosis. Suberoyl hydroxamic acid (SAHA) is a broad-spectrum histone deacetylase inhibitor (HDACi) suppressing family members in multiple HDAC classes. Increasing evidence indicates that SAHA and other HDACi can, in addition to mitochondria-mediated apoptosis, also promote caspase-independent autophagy. SAHA-induced mTOR inactivation as a major regulator of autophagy activating the remaining autophagic core machinery is by far the most reported pathway in several tumor models. However, the question of which upstream mechanisms regulate SAHA-induced mTOR inactivation that consequently initiate autophagy has been mainly left unexplored. To elucidate this issue, we recently initiated a study clarifying different modes of SAHA-induced cell death in two human uterine sarcoma cell lines which led to the conclusion that the tumor suppressor protein p53 could act as a molecular switch between SAHA-triggered autophagic or apoptotic cell death. In this review, we present current research evidence about HDACi-mediated apoptotic and autophagic pathways, in particular with regard to p53 and its therapeutic implications. 10.3390/ijms18091883
    Histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), enhances anti-tumor effects of the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib in triple-negative breast cancer cells. Min Ahrum,Im Seock-Ah,Kim Debora Keunyoung,Song Sang-Hyun,Kim Hee-Jun,Lee Kyung-Hun,Kim Tae-Yong,Han Sae-Won,Oh Do-Youn,Kim Tae-You,O'Connor Mark J,Bang Yung-Jue Breast cancer research : BCR INTRODUCTION:Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, has been found to have therapeutic potential for treating cancers associated with impaired DNA repair capabilities, particularly those with deficiencies in the homologous recombination repair (HRR) pathway. Histone deacetylases (HDACs) are important for enabling functional HRR of DNA by regulating the expression of HRR-related genes and promoting the accurate assembly of HRR-directed sub-nuclear foci. Thus, HDAC inhibitors have recently emerged as a therapeutic agent for treating cancer by inhibiting DNA repair. Based on this, HDAC inhibition could be predicted to enhance the anti-tumor effect of PARP inhibitors in cancer cells by blocking the HRR pathway. METHODS:We determined whether suberoylanilide hydroxamic acid (SAHA), a HDAC inhibitor, could enhance the anti-tumor effects of olaparib on breast cancer cell lines using a cytotoxic assay, cell cycle analysis, and Western blotting. We evaluated how exposure to SAHA affects the expression of HRR-associated genes. The accumulation of DNA double strand breaks (DSBs) induced by combination treatment was assessed. Induction of autophagy was monitored by imaging green fluorescent protein-tagged microtubule-associated protein 1A/1B-light chain 3 (LC3) expression following co-treatment with olaparib and SAHA. These in vitro data were validated in vivo using a human breast cancer xenograft model. RESULTS:Triple-negative breast cancer cell (TNBC) lines showed heterogeneous responses to the PARP and HDAC inhibitors. Co-administration of olaparib and SAHA synergistically inhibited the growth of TNBC cells that expressed functional Phosphatase and tensin homolog (PTEN). This effect was associated with down-regulation of the proliferative signaling pathway, increased apoptotic and autophagic cell death, and accumulation of DNA damage. The combined anti-tumor effect of olaparib and SAHA was also observed in a xenograft model. These data suggest that PTEN expression in TNBC cells can sensitize the cell response to simultaneous inhibition of PARP and HDAC both in vitro and in vivo. CONCLUSION:Our findings suggest that expression of functional PTEN may serve as a biomarker for selecting TNBC patients that would favorably respond to a combination of olaparib with SAHA. This provides a strong rationale for treating TNBC patients with PTEN expression with a combination therapy consisting of olaparib and SAHA. 10.1186/s13058-015-0534-y
    Histone deacetylase inhibitors suppress mutant p53 transcription via histone deacetylase 8. Yan W,Liu S,Xu E,Zhang J,Zhang Y,Chen X,Chen X Oncogene Mutation of the p53 gene is the most common genetic alteration in human cancer and contributes to malignant process by enhancing transformed properties of cells and resistance to anticancer therapy. Mutant p53 is often highly expressed in tumor cells at least, in part, due to its increased half-life. However, whether mutant p53 expression is regulated by other mechanisms in tumors is unclear. Here we found that histone deacetylase (HDAC) inhibitors suppress both wild-type and mutant p53 transcription in time- and dose-dependent manners. Consistent with this, the levels of wild-type and mutant p53 proteins are decreased upon treatment with HDAC inhibitors. Importantly, we found that upon knockdown of each class I HDAC, only HDAC8 knockdown leads to decreased expression of wild-type and mutant p53 proteins and transcripts. Conversely, we found that ectopic expression of wild-type, but not mutant HDAC8, leads to increased transcription of p53. Furthermore, we found that knockdown of HDAC8 results in reduced expression of HoxA5 and consequently, attenuated ability of HoxA5 to activate p53 transcription, which can be rescued by ectopic expression of HoxA5. Because of the fact that HDAC8 is required for expression of both wild-type and mutant p53, we found that targeted disruption of HDAC8 expression remarkably triggers proliferative defect in cells with a mutant, but not wild-type, p53. Together, our data uncover a regulatory mechanism of mutant p53 transcription via HDAC8 and suggest that HDAC inhibitors and especially HDAC8-targeting agents might be explored as an adjuvant for tumors carrying a mutant p53. 10.1038/onc.2012.81
    Triple-Negative Breast Cancer: The Progress of Targeted Therapies and Future Tendencies. Damaskos Christos,Garmpi Anna,Nikolettos Konstantinos,Vavourakis Michail,Diamantis Evangelos,Patsouras Alexandros,Farmaki Paraskevi,Nonni Afroditi,Dimitroulis Dimitrios,Mantas Dimitrios,Antoniou Efstathios A,Nikolettos Nikos,Kontzoglou Konstantinos,Garmpis Nikolaos Anticancer research Triple-negative breast cancer (TNBC) is characterized by a lack of expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) and unfortunately is not associated with good prognosis. Treatment of breast cancer mainly depends on chemotherapy, due to the lack of specifically approved targeted therapies for TNBC. It is of paramount importance to find new therapeutic approaches, as resistance to chemotherapy frequently occurs. Herein, we present clinical studies published within the last five years, in order to reveal possible targeted therapies against TNBC. We aimed to discuss factors against TNBC, such as tyrosine kinase inhibitors, anti-androgens, poly ADP-ribose polymerase-1 (PARP-1) inhibitors, anti-angiogenic factors, immune checkpoints and histone deacetylase inhibitors (HDACI). Furthermore, the PI3K/AKT/mTOR pathway seems to be a promising field for the development of new anti-TNBC targeted therapies. Data from 18 clinical trials with patients suffering from TNBC were summarized and presented descriptively. 10.21873/anticanres.13722
    Combination of the novel histone deacetylase inhibitor YCW1 and radiation induces autophagic cell death through the downregulation of BNIP3 in triple-negative breast cancer cells in vitro and in an orthotopic mouse model. Chiu Hui-Wen,Yeh Ya-Ling,Wang Yi-Ching,Huang Wei-Jan,Ho Sheng-Yow,Lin Pinpin,Wang Ying-Jan Molecular cancer BACKGROUND:Triple-negative breast cancer (TNBC) is the most aggressive and invasive of the breast cancer subtypes. TNBC is a challenging disease that lacks targets for treatment. Histone deacetylase inhibitors (HDACi) are a group of targeted anticancer agents that enhance radiosensitivity. Bcl-2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) is a member of the Bcl-2 subfamily. BNIP3 is not found in normal breast tissue but is up-regulated in breast cancer. In the present study, we investigated the anti-cancer effects of a newly developed HDACi, YCW1, combined with ionizing radiation (IR) in TNBC in vitro and in an orthotopic mouse model. Furthermore, we examined the relationship between autophagy and BNIP3. METHODS:Trypan blue exclusion was used to investigate the viability of 4 T1 (a mouse TNBC cell line) and MDA-MB-231 cells (a human TNBC cell line) following combined YCW1 and IR treatment. Flow cytometry was used to determine apoptosis and autophagy. The expression levels of BNIP3, endoplasmic reticulum (ER) stress- and autophagic-related proteins were measured using western blot analysis. An orthotopic mouse model was used to investigate the in vivo effects of YCW1 and IR alone and in combination. Tumor volumes were monitored using a bioluminescence-based IVIS Imaging System 200. RESULTS:We found that YCW1 significantly enhanced toxicity in 4 T1 cells compared with suberoylanilide hydroxamic acid (SAHA), which was the first HDACi approved by the Food and Drug Administration for clinical use in cancer patients. The combined treatment of YCW1 and IR enhanced cytotoxicity by inducing ER stress and increasing autophagy induction. Additionally, the combined treatment caused autophagic flux and autophagic cell death. Furthermore, the expression level of BNIP3 was significantly decreased in cells following combined treatment. The downregulation of BNIP3 led to a significant increase in autophagy and cytotoxicity. The combined anti-tumor effects of YCW1 and IR were also observed in an orthotopic mouse model; combination therapy resulted in a significant increase in autophagy and decreased tumor tissue expression of BNIP3 in the tumor tissue. CONCLUSIONS:These data support the possibility of using a combination of HDACi and IR in the treatment of TNBC. Moreover, BNIP3 may be a potential target protein for TNBC treatment. 10.1186/s12943-016-0531-5
    Histone Deacetylase Inhibitors: An Attractive Therapeutic Strategy Against Breast Cancer. Damaskos Christos,Garmpis Nikolaos,Valsami Serena,Kontos Michael,Spartalis Eleftherios,Kalampokas Theodoros,Kalampokas Emmanouil,Athanasiou Antonios,Moris Demetrios,Daskalopoulou Afrodite,Davakis Spyridon,Tsourouflis Gerasimos,Kontzoglou Konstantinos,Perrea Despina,Nikiteas Nikolaos,Dimitroulis Dimitrios Anticancer research With a lifetime risk estimated to be one in eight in industrialized countries, breast cancer is the most frequent type of cancer among women worldwide. Patients are often treated with anti-estrogens, but it is common that some tumors develop resistance to therapy. The causation and progression of cancer is controlled by epigenetic processes, so there is an ongoing interest in research into mechanisms, genes and signaling pathways associating carcinogenesis with epigenetic modulation of gene expression. Given the fact that histone deacetylases (HDACs) have a great impact on chromatin remodeling and epigenetics, their inhibitors have become a very interesting field of research. AIM:This review focused on the use of HDAC inhibitors as anticancer treatment and explains the mechanisms of therapeutic effects on breast cancer. We anticipate further clinical benefits of this new class of drugs, both as single agents and in combination therapy. Molecules such as suberoylanilide hydroxamic acid, trichostatin A, suberoylbis-hydroxamic acid, panobinostat, entinostat, valproic acid, sodium butyrate, SK7041, FTY720, N-(2-hydroxyphenyl)-2-propylpentanamide, Scriptaid, YCW1, santacruzamate A and ferrocenyl have shown promising antitumor effects against breast cancer. HDAC inhibitors consists an attractive field for targeted therapy against breast cancer. Future therapeutic strategies will include combination of HDAC inhibitors and chemotherapy or other inhibitors, in order to target multiple oncogenic signaling pathways. More trials are needed. 10.21873/anticanres.11286
    Histone Deacetylases as New Therapeutic Targets in Triple-negative Breast Cancer: Progress and Promises. Garmpis Nikolaos,Damaskos Christos,Garmpi Anna,Kalampokas Emmanouil,Kalampokas Theodoros,Spartalis Eleftherios,Daskalopoulou Afrodite,Valsami Serena,Kontos Michael,Nonni Afroditi,Kontzoglou Konstantinos,Perrea Despina,Nikiteas Nikolaos,Dimitroulis Dimitrios Cancer genomics & proteomics Triple-negative breast cancer (TNBC) lacks expression of estrogen receptor (ER), progesterone receptor (PR) and HER2 gene. It comprises approximately 15-20% of breast cancers (BCs). Unfortunately, TNBC's treatment continues to be a clinical problem because of its relatively poor prognosis, its aggressiveness and the lack of targeted therapies, leaving chemotherapy as the mainstay of treatment. It is essential to find new therapies against TNBC, in order to surpass the resistance and the invasiveness of already existing therapies. Given the fact that epigenetic processes control both the initiation and progression of TNBC, there is an increasing interest in the mechanisms, molecules and signaling pathways that participate at the epigenetic modulation of genes expressed in carcinogenesis. The acetylation of histone proteins provokes the transcription of genes involved in cell growth, and the expression of histone deacetylases (HDACs) is frequently up-regulated in many malignancies. Unfortunately, in the field of BC, HDAC inhibitors have shown limited effect as single agents. Nevertheless, their use in combination with kinase inhibitors, autophagy inhibitors, ionizing radiation, or two HDAC inhibitors together is currently being evaluated. HDAC inhibitors such as suberoylanilidehydroxamic acid (SAHA), sodium butyrate, mocetinostat, panobinostat, entinostat, YCW1 and N-(2-hydroxyphenyl)-2-propylpentanamide have shown promising therapeutic outcomes against TNBC, especially when they are used in combination with other anticancer agents. More studies concerning HDAC inhibitors in breast carcinomas along with a more accurate understanding of the TNBC's pathobiology are required for the possible identification of new therapeutic strategies. 10.21873/cgp.20041
    Targeting breast cancer stem cells in triple-negative breast cancer using a combination of LBH589 and salinomycin. Kai Masaya,Kanaya Noriko,Wu Shang V,Mendez Carlos,Nguyen Duc,Luu Thehang,Chen Shiuan Breast cancer research and treatment The aim of this study is to investigate the efficacy of combining a histone deacetylase inhibitor (LBH589) and a breast cancer stem cells (BCSC)-targeting agent (salinomycin) as a novel combination therapy for triple-negative breast cancer (TNBC). We performed in vitro studies using the TNBC cell lines to examine the combined effect. We used the mammosphere and ALDEFLUOR assays to estimate BCSC self-renewal capacity and distribution of BCSCs, respectively. Synergistic analysis was performed using CalcuSyn software. For in vivo studies, aldehyde dehydrogenase 1 ALDH1-positive cells were injected into non-obese diabetic/severe combined immunodeficiency gamma (NSG) mice. After tumor formation, mice were treated with LBH589, salinomycin, or in combination. In a second mouse model, HCC1937 cells were first treated with each treatment and then injected into NSG mice. For mechanistic analysis, immunohistochemistry and Western blot analysis were performed using cell and tumor samples. HCC1937 cells displayed BCSC properties including self-renewal capacity, an ALDH1-positive cell population, and the ability to form tumors. Treatment of HCC1937 cells with LBH589 and salinomycin had a potent synergistic effect inhibiting TNBC cell proliferation, ALDH1-positive cells, and mammosphere growth. In xenograft mouse models treated with LBH589 and salinomycin, the drug combination effectively and synergistically inhibited tumor growth of ALDH1-positive cells. The drug combination exerted its effects by inducing apoptosis, arresting the cell cycle, and regulating epithelial-mesenchymal transition (EMT). Combination of LBH589 and salinomycin has a synergistic inhibitory effect on TNBC BCSCs by inducing apoptosis, arresting the cell cycle, and regulating EMT; with no apparent associated severe toxicity. This drug combination could therefore offer a new targeted therapeutic strategy for TNBC and warrants further clinical study in patients with TNBC. 10.1007/s10549-015-3376-5
    Epigenetic reprogramming of epithelial mesenchymal transition in triple negative breast cancer cells with DNA methyltransferase and histone deacetylase inhibitors. Su Yanrong,Hopfinger Nathan R,Nguyen Theresa D,Pogash Thomas J,Santucci-Pereira Julia,Russo Jose Journal of experimental & clinical cancer research : CR BACKGROUND:Triple negative breast cancer (TNBC) is an aggressive neoplasia with no effective therapy. Our laboratory has developed a unique TNBC cell model presenting epithelial mesenchymal transition (EMT) a process known to be important for tumor progression and metastasis. There is increasing evidence showing that epigenetic mechanisms are involved in the activation of EMT. The objective of this study is to epigenetically reverse the process of EMT in TNBC by using DNA methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi). METHODS:We evaluated the antitumor effect of three DNMTi and six HDACi using our TNBC cell model by MTT assay, migration and invasion assay, three dimensional culture, and colony formation assay. We then performed the combined treatment both in vitro and in vivo using the most potent DNMTi and HDACi, and tested the combined treatment in a panel of breast cancer cell lines. We investigated changes of EMT markers and potential signaling pathways associated with the antitumor effects. RESULTS:We showed that DNMTi and HDACi can reprogram highly aggressive TNBC cells that have undergone EMT to a less aggressive phenotype. SGI-110 and MS275 are superior to other seven compounds being tested. The combination of SGI with MS275 exerts a greater effect than single agent alone in inhibiting cell proliferation, motility, colony formation, and stemness of cancer cells. We also demonstrated that MS275 and the combination of SGI with MS275 exert in vivo antitumor effect. We revealed that the combined treatment synergistically reverses EMT through inhibiting EpCAM cleavage and WNT signaling, suppressing mutant p53, ZEB1, and EZH2, and inducing E-cadherin, apoptosis, as well as histone H3 tri-methylation. CONCLUSIONS:Our study showed that DNMTi and HDACi exert antitumor activity in TNBC cells partially by epigenetically reprograming EMT. Our findings strongly suggest that TNBC is sensitive to epigenetic therapies. Therefore, we propose a new strategy to treat TNBC by using the combination of SGI-110 with MS275, which exerts superior antitumor effects by simultaneously targeting multiple pathways. 10.1186/s13046-018-0988-8
    An overview of investigational Histone deacetylase inhibitors (HDACis) for the treatment of non-Hodgkin's lymphoma. Apuri Susmitha,Sokol Lubomir Expert opinion on investigational drugs INTRODUCTION:Histone acetylation alters DNA transcription and protein expression. Aberrant acetylation is seen in tumor cells. Histone deacetylase inhibitors (HDACis) act by modifying gene expression and are the newest class of drugs shown to be promising in patients with several malignancies including relapsed and/or refractory lymphoma. Multiple HDACis are currently under various phases of clinical trials for the treatment of Non-Hodgkin's lymphoma (NHL). AREAS COVERED:This review discusses the mechanism of histone acetyl transferases (HAT's), histone deacetylases (HDAC's) and their role in B - and T-cell malignancies with a particular focus on the mechanism of action and clinical application of HDACis in NHL. Discussion includes: HDACi's like vorinostat, romidepsin, belinostat, panobinostat, entinostat and chidamide; pivotal clinical trials leading to the approval of HDACis in NHL; ongoing active clinical trials and combination therapies with novel agents. EXPERT OPINION:Relapsed and or refractory lymphoma poses a challenge to the clinician given the poor outcomes. HDACis show promising clinical activity in patients with relapsed/refractory NHL. Active pursuit of developing newer HDACis and clinical trials using combination therapies that help understand the molecular characteristics and synergistic actions of these agents is warranted. This would help improve efficacy, drug tolerability and expand the horizon of these novel agents. 10.1517/13543784.2016.1164140
    Histone Deacetylase Inhibitor Enhances the Efficacy of MEK Inhibitor through NOXA-Mediated MCL1 Degradation in Triple-Negative and Inflammatory Breast Cancer. Torres-Adorno Angie M,Lee Jangsoon,Kogawa Takahiro,Ordentlich Peter,Tripathy Debu,Lim Bora,Ueno Naoto T Clinical cancer research : an official journal of the American Association for Cancer Research Inflammatory breast cancer (IBC), diagnosed clinically, and triple-negative breast cancer (TNBC), diagnosed by molecular receptor status, are the two most aggressive forms of breast cancer, and both lack effective targeted therapies. We previously demonstrated involvement of histone deacetylase (HDAC) inhibitor entinostat in regulating apoptosis in IBC and TNBC cells; here, we aimed to identify novel combination therapy candidates. Potential therapeutic targets were identified by mRNA expression profiling of TNBC and IBC cells treated with entinostat. Drug action and synergism were assessed by proliferation assays, tumor growth , and proteomic analyses. Gain/loss-of-expression studies were utilized to functionally validate the role of identified targets in sensitivity of TNBC and IBC cells to combination therapy. Entinostat induced activity of the oncogenic ERK pathway and expression of proapoptotic NOXA. These are known to stabilize and degrade, respectively, MCL1, an antiapoptotic Bcl-2 protein. In breast cancer patients, high-MCL1/low-NOXA tumor expression correlated significantly with poor survival outcomes. Combination treatment of entinostat with MEK inhibitor pimasertib reduced the growth of TNBC and IBC cells and inhibited tumor growth The synergistic action of combination therapy was observed in TNBC and IBC cell lines in which NOXA expression was induced following entinostat treatment. The therapeutic activity depended on induction of mitochondrial cell death pathways initiated by NOXA-mediated MCL1 degradation. Our preclinical findings provide a rationale for the clinical testing of combination HDAC and MEK pathway inhibition for TNBC and IBC that exhibit elevated baseline tumor MCL1 expression. . 10.1158/1078-0432.CCR-16-2622
    Histone deacetylase inhibitors: signalling towards p21cip1/waf1. Ocker Matthias,Schneider-Stock Regine The international journal of biochemistry & cell biology Chromatin-modifying enzymes such as histone deacetylases (HDAC) facilitate a closed chromatin structure and hence transcriptional repression. HDAC are commonly affected in human cancer diseases. Thus, inhibition of HDAC represents a novel therapeutic approach. Several studies have shown that HDAC inhibitors strongly activate the expression of the cyclin-dependent kinase inhibitor p21(cip1/waf1) through (i) enhanced histone acetylation around the p21(cip1/waf1) promoter and (ii) the Sp1 sites on the p21(cip1/waf1) promoter releasing the repressor HDAC1 from its binding. p21(cip1/waf1) expression is regulated in a p53-dependent and p53-independent manner. The decision if p21(cip1/waf1) up-regulation results in cell cycle arrest or apoptosis, decides about the therapeutic efficacy of an anti-cancer treatment with HDAC inhibitors. 10.1016/j.biocel.2007.03.001
    Novel histone deacetylase inhibitor CG200745 induces clonogenic cell death by modulating acetylation of p53 in cancer cells. Oh Eun-Taex,Park Moon-Taek,Choi Bo-Hwa,Ro Seonggu,Choi Eun-Kyung,Jeong Seong-Yun,Park Heon Joo Investigational new drugs Histone deacetylase (HDAC) plays an important role in cancer onset and progression. Therefore, inhibition of HDAC offers potential as an effective cancer treatment regimen. CG200745, (E)-N(1)-(3-(dimethylamino)propyl)-N(8)-hydroxy-2-((naphthalene-1-loxy)methyl)oct-2-enediamide, is a novel HDAC inhibitor presently undergoing a phase I clinical trial. Enhancement of p53 acetylation by HDAC inhibitors induces cell cycle arrest, differentiation, and apoptosis in cancer cells. The purpose of the present study was to investigate the role of p53 acetylation in the cancer cell death caused by CG200745. CG200745-induced clonogenic cell death was 2-fold greater in RKO cells expressing wild-type p53 than in p53-deficient RC10.1 cells. CG200745 treatment was also cytotoxic to PC-3 human prostate cancer cells, which express wild-type p53. CG200745 increased acetylation of p53 lysine residues K320, K373, and K382. CG200745 induced the accumulation of p53, promoted p53-dependent transactivation, and enhanced the expression of MDM2 and p21(Waf1/Cip1) proteins, which are encoded by p53 target genes. An examination of CG200745 effects on p53 acetylation using cells transfected with various p53 mutants showed that cells expressing p53 K382R mutants were significantly resistant to CG200745-induced clonogenic cell death compared with wild-type p53 cells. Moreover, p53 transactivation in response to CG200745 was suppressed in all cells carrying mutant forms of p53, especially K382R. Taken together, these results suggest that acetylation of p53 at K382 plays an important role in CG200745-induced p53 transactivation and clonogenic cell death. 10.1007/s10637-010-9568-2
    Histone deacetylase inhibitor induces cell apoptosis and cycle arrest in lung cancer cells via mitochondrial injury and p53 up-acetylation. Bao Lianmin,Diao Hua,Dong Nian,Su Xiaoqiong,Wang Bingbin,Mo Qiongya,Yu Heguo,Wang Xiangdong,Chen Chengshui Cell biology and toxicology The reversibility of non-genotoxic phenotypic changes has been explored in order to develop novel preventive and therapeutic approaches for cancer. Quisinostat (JNJ-26481585), a novel second-generation histone deacetylase inhibitor (HDACi), has efficient therapeutic actions on non-small cell lung cancer (NSCLC) cell. The present study aims at investigating underlying molecular mechanisms involved in the therapeutic activity of quisinostat on NSCLC cells. We found that quisinostat significantly inhibited A549 cell proliferation in dose- and time-dependent manners. Up-acetylation of histones H3 and H4 and non-histone protein α-tubulin was induced by quisinostat treatment in a nanomolar concentration. We also demonstrated that quisinostat increased reactive oxygen species (ROS) production and destroyed mitochondrial membrane potential (ΔΨm), inducing mitochondria-mediated cell apoptosis. Furthermore, exposure of A549 cells to quisinostat significantly suppressed cell migration by inhibiting epithelial-mesenchymal transition (EMT) process. Bioinformatics analysis indicated that effects of quisinostat on NSCLC cells were associated with activated p53 signaling pathway. We found that quisinostat increased p53 acetylation at K382/K373 sites, upregulated the expression of p21, and resulted in G1 phase arrest. Thus, our results suggest that the histone deacetylase can be a therapeutic target of NSCLC to discover and develop a new category of therapy for lung cancer. 10.1007/s10565-016-9347-8
    A novel class I histone deacetylase inhibitor, I-7ab, induces apoptosis and arrests cell cycle progression in human colorectal cancer cells. Yang Liyan,Liang Qiannan,Shen Ke,Ma Li,An Na,Deng Weiping,Fei Zhewei,Liu Jianwen Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie Epigenetic mutations are closely associated with human diseases, especially cancers. Among them, dysregulations of histone deacetylases (HDACs) are commonly observed in human cancers. Recent years, HDAC inhibitors have been identified as promising anticancer agents; several HDAC inhibitors have been applied in clinical practice. In this study, we synthesized a novel N-hydroxyacrylamide-derived HDAC inhibitor, I-7ab, and examined its antitumor activity. Our investigations demonstrated that I-7ab exerted cytotoxicity toward and inhibited the growth of human cancer cell lines at micromolar concentrations. Among tested cells, HCT116 was the most sensitive one to the treatment of I-7ab. However, I-7ab displayed far less cytotoxicity in human normal cells. In HCT116 cells, I-7ab inhibited the expression of class I HDACs, especially that of HDAC3, and suppressed EGFR signaling pathway. With respect to the cytotoxic effect of I-7ab, it induced apoptosis via increasing the Bax/Bcl-2 ratio and suppressing the translocation of NF-κB. Other than inducing apoptosis, I-7ab inhibited the expression of cyclin B1 and thereby arrests cell cycle progression at G2/M phase. Further analyses revealed potential role of p53 and p21 in I-7ab-induced apoptosis and cell cycle arrest. According to our findings, I-7ab may serve as a lead compound for potential antitumor drugs. 10.1016/j.biopha.2015.02.019
    Molecular Signatures Associated with Treatment of Triple-Negative MDA-MB231 Breast Cancer Cells with Histone Deacetylase Inhibitors JAHA and SAHA. Librizzi Mariangela,Caradonna Fabio,Cruciata Ilenia,Dębski Janusz,Sansook Supojjanee,Dadlez Michał,Spencer John,Luparello Claudio Chemical research in toxicology Jay Amin hydroxamic acid (JAHA; N8-ferrocenylN-hydroxy-octanediamide) is a ferrocene-containing analogue of the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA). JAHA's cytotoxic activity on MDA-MB231 triple negative breast cancer (TNBC) cells at 72 h has been previously demonstrated with an IC of 8.45 μM. JAHA's lethal effect was found linked to perturbations of cell cycle, mitochondrial activity, signal transduction, and autophagy mechanisms. To glean novel insights on how MDA-MB231 breast cancer cells respond to the cytotoxic effect induced by JAHA, and to compare the biological effect with the related compound SAHA, we have employed a combination of differential display-PCR, proteome analysis, and COMET assay techniques and shown some differences in the molecular signature profiles induced by exposure to either HDACis. In particular, in contrast to the more numerous and diversified changes induced by SAHA, JAHA has shown a more selective impact on expression of molecular signatures involved in antioxidant activity and DNA repair. Besides expanding the biological knowledge of the effect exerted by the modifications in compound structures on cell phenotype, the molecular elements put in evidence in our study may provide promising targets for therapeutic interventions on TNBCs. 10.1021/acs.chemrestox.7b00269
    Divergent JNK Phosphorylation of HDAC3 in Triple-Negative Breast Cancer Cells Determines HDAC Inhibitor Binding and Selectivity. Hanigan Thomas W,Aboukhatwa Shaimaa M,Taha Taha Y,Frasor Jonna,Petukhov Pavel A Cell chemical biology Histone deacetylase (HDAC) catalytic activity is regulated by formation of co-regulator complexes and post-translational modification. Whether these mechanisms are transformed in cancer and how this affects the binding and selectivity of HDAC inhibitors (HDACis) is unclear. In this study, we developed a method that identified a 3- to 16-fold increase in HDACi selectivity for HDAC3 in triple-negative breast cancer (TNBC) cells in comparison with luminal subtypes that was not predicted by current practice measurements with recombinant proteins. We found this increase was caused by c-Jun N-terminal kinase (JNK) phosphorylation of HDAC3, was independent of HDAC3 complex composition or subcellular localization, and was associated with a 5-fold increase in HDAC3 enzymatic activity. This study points to HDAC3 and the JNK axes as targets in TNBC, highlights how HDAC phosphorylation affects HDACi binding and selectivity, and outlines a method to identify changes in individual HDAC isoforms catalytic activity, applicable to any disease state. 10.1016/j.chembiol.2017.08.015
    Suberoylanilide hydroxamic acid (SAHA) promotes the epithelial mesenchymal transition of triple negative breast cancer cells via HDAC8/FOXA1 signals. Wu Shao,Luo Zhi,Yu Peng-Jiu,Xie Hui,He Yu-Wen Biological chemistry Inhibitor of histone deacetylases (HDACIs) have great therapeutic value for triple negative breast cancer (TNBC) patients. Interestingly, our present study reveals that suberoyl anilide hydroxamic acid (SAHA), one of the most advanced pan-HDAC inhibitor, can obviously promote in vitro motility of MDA-MB-231 and BT-549 cells via induction of epithelial-mesenchymal transition (EMT). SAHA treatment significantly down-regulates the expression of epithelial markers E-cadherin (E-Cad) while up-regulates the mesenchymal markers N-cadherin (N-Cad), vimentin (Vim) and fibronectin (FN). However, SAHA has no effect on the expression and nuclear translocation of EMT related transcription factors including Snail, Slug, Twist and ZEB. While SAHA treatment down-regulates the protein and mRNA expression of FOXA1 and then decreases its nuclear translocation. Over-expression of FOXA1 markedly attenuates SAHA induced EMT of TNBC cells. Further, silence of HDAC8, while not HDAC6, alleviates the down-regulation of FOXA1 and up-regulation of N-Cad and Vim in MDA-MB-231 cells treated with SAHA. Collectively, our present study reveals that SAHA can promote EMT of TNBC cells via HDAC8/FOXA1 signals, which suggests that more attention should be paid when SAHA is used as anti-cancer agent for cancer treatment. 10.1515/hsz-2015-0215
    Differences in Expression of Key DNA Damage Repair Genes after Epigenetic-Induced BRCAness Dictate Synthetic Lethality with PARP1 Inhibition. Wiegmans Adrian P,Yap Pei-Yi,Ward Ambber,Lim Yi Chieh,Khanna Kum Kum Molecular cancer therapeutics The triple-negative breast cancer (TNBC) subtype represents a cancer that is highly aggressive with poor patient outcome. Current preclinical success has been gained through synthetic lethality, targeting genome instability with PARP inhibition in breast cancer cells that harbor silencing of the homologous recombination (HR) pathway. Histone deacetylase inhibitors (HDACi) are a class of drugs that mediate epigenetic changes in expression of HR pathway genes. Here, we compare the activity of the pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA), the class I/IIa HDAC inhibitor valproic acid (VPA), and the HDAC1/2-specific inhibitor romidepsin (ROMI) for their capability to regulate DNA damage repair gene expression and in sensitizing TNBC to PARPi. We found that two of the HDACis tested, SAHA and ROMI, but not VPA, indeed inhibit HR repair and that RAD51, BARD1, and FANCD2 represent key proteins whose inhibition is required for HDACi-mediated therapy with PARP inhibition in TNBC. We also observed that restoration of BRCA1 function stabilizes the genome compared with mutant BRCA1 that results in enhanced polyploid population after combination treatment with HDACi and PARPi. Furthermore, we found that overexpression of the key HR protein RAD51 represents a mechanism for this resistance, promoting aberrant repair and the enhanced polyploidy observed. These findings highlight the key components of HR in guiding synthetic lethality with PARP inhibition and support the rationale for utilizing the novel combination of HDACi and PARPi against TNBC in the clinical setting. 10.1158/1535-7163.MCT-15-0374
    A New Histone Deacetylase Inhibitor Enhances Radiation Sensitivity through the Induction of Misfolded Protein Aggregation and Autophagy in Triple-Negative Breast Cancer. Chiu Hui-Wen,Yeh Ya-Ling,Ho Sheng-Yow,Wu Yuan-Hua,Wang Bour-Jr,Huang Wei-Jan,Ho Yuan-Soon,Wang Ying-Jan,Chen Li-Ching,Tu Shih-Hsin Cancers Radiation therapy (RT) is one of the main treatments for triple-negative breast cancer (TNBC). However, many patients experience RT failure due to the metastatic potential of RT and the radiation resistance of several cancers. Histone deacetylase inhibitors (HDACis) can serve as radiosensitizers. In this study, we investigated whether a novel HDACi, TMU-35435, could reinforce radiosensitivity through the induction of misfolded protein aggregation and autophagy in TNBC. Significantly enhanced toxicity was found for the combination treatment compared with TMU-35435 or irradiation (IR) treatment alone in TNBC cells. The combination treatment induced misfolded protein aggregation and TMU-35435 inhibited the interaction of HDAC6 with dynein. Furthermore, the combined treatment induced endoplasmic reticulum (ER) stress but did not trigger apoptosis. In addition, the combination treatment caused autophagic cell death. Tumor growth in the mouse of model orthotopic breast cancer was suppressed by the combination treatment through the induction of ER stress and autophagy. These findings support the future evaluation of the novel HDACi TMU-35435, as a potent radiosensitizer in TNBC. 10.3390/cancers11111703
    HDAC inhibition does not induce estrogen receptor in human triple-negative breast cancer cell lines and patient-derived xenografts. de Cremoux Patricia,Dalvai Mathieu,N'Doye Olivia,Moutahir Fatima,Rolland Gaëlle,Chouchane-Mlik Olfa,Assayag Franck,Lehmann-Che Jacqueline,Kraus-Berthie Laurence,Nicolas André,Lockhart Brian Paul,Marangoni Elisabetta,de Thé Hugues,Depil Stéphane,Bystricky Kerstin,Decaudin Didier Breast cancer research and treatment Several publications have suggested that histone deacetylase inhibitors (HDACis) could reverse the repression of estrogen receptor alpha (ERα) in triple-negative breast cancer (TNBC) cell lines, leading to the induction of a functional protein. Using different HDACis, vorinostat, panobinostat, and abexinostat, we therefore investigated this hypothesis in various human TNBC cell lines and patient-derived xenografts (PDXs). We used three human TNBC cell lines and three PDXs. We analyzed the in vitro toxicity of the compounds, their effects on the hormone receptors and hormone-related genes and protein expression both in vitro and in vivo models. We then explored intra-tumor histone H3 acetylation under abexinostat in xenograft models. Despite major cytotoxicity of all tested HDAC inhibitors and repression of deactylation-dependent CCND1 gene, neither ERα nor ERβ, ESR1 or ESR2 genes respectively, were re-expressed in vitro. In vivo, after administration of abexinostat for three consecutive days, we did not observe any induction of ESR1 or ESR1-related genes and ERα protein expression by RT-qPCR and immunohistochemical methods in PDXs. This observation was concomitant to the fact that in vivo administration of abexinostat increased intra-tumor histone H3 acetylation. These observations do not allow us to confirm previous studies which suggested that HDACis are able to convert ER-negative (ER-) tumors to ER-positive (ER+) tumors, and that a combination of HDAC inhibitors and hormone therapy could be proposed in the management of TNBC patients. 10.1007/s10549-014-3233-y
    Histone deacetylase inhibitors suppress mutant p53 transcription via HDAC8/YY1 signals in triple negative breast cancer cells. Wang Zhao-Tong,Chen Zhuo-Jia,Jiang Guan-Min,Wu Ying-Min,Liu Tao,Yi Yan-Mei,Zeng Jun,Du Jun,Wang Hong-Sheng Cellular signalling There is an urgent need to investigate the potential targeted therapy approach for triple-negative breast cancer (TNBC). Our present study reveals that histone deacetylase inhibitors (HDACIs) suberoyl anilide hydroxamic acid (SAHA) and sodium butyrate (NaB) significantly inhibit cell proliferation, arrest cell cycle at G0/G1 phase, and induce mitochondrial related apoptosis of TNBC cells. Further, SAHA and NaB decrease the phosphorylation, protein and mRNA levels of mutant p53 (mtp53) in TNBC cells. While SAHA or NaB has no similar inhibition effect on wild type p53 (wtp53). The inhibition apparently occurs at the level of transcription because the down regulation of precursor p53 transcription is much more rapid (less than 2h) and sharp than that of mature p53. The knockdown of HDAC8, while not HDAC6, inhibits the transcription of mtp53 in TNBC cells. The luciferase assay and ChIP analysis reveal that both SAHA and NaB can reduce the binding of transcription factor Yin Yang 1 (YY1) with the -102 to -96 position of human p53 promoter. Knockdown of YY1 also significantly inhibits the transcription of mtp53 in TNBC cells. Further, SAHA and NaB can inhibit the association of HDAC8 and YY1, increase acetylation of residues 170-200 of YY1, then decrease its transcription activities, and finally suppress YY1 induced p53 transcription. Together, our data establish that SAHA and NaB can be considered as drug candidates for TNBC patients, and HDAC8/YY1/mtp53 signals act as an important target for TNBC treatment. 10.1016/j.cellsig.2016.02.006
    Targeting triple negative breast cancer with histone deacetylase inhibitors. Fedele Palma,Orlando Laura,Cinieri Saverio Expert opinion on investigational drugs INTRODUCTION:Triple negative breast cancer (TNBC) is a heterogeneous disease characterized by poor outcomes, higher rates of relapse, lack of biomarkers for rational use of targeted treatments and insensitivity to current available treatments. Histone deacetylase inhibitors (HDACis) perform multiple cytotoxic actions and are emerging as promising multifunctional agents in TNBC. Areas covered: This review focuses on the challenges so far addressed in the targeted treatment of TNBC and explores the various mechanisms by which HDACis control cancer cell growth, tumor progression and metastases. Pivotal preclinical trials on HDACis like panobinostat, vorinostat, and entinostat show that these epigenetic agents exert an anti-proliferative effect on TNBC cells and control tumor growth by multiple mechanisms of action, including apoptosis and regulation of the epithelial to mesenchimal transition (EMT). Combination studies have reported the synergism of HDACis with other anticancer agents. Expert opinion: In recent years, treatment of TNBC has recorded a high number of failures in the development of targeted agents. HDACis alone or in combination strategies show promising activity in TNBC and could have implications for the future targeted treatment of TNBC patients. Future research should identify which agent synergizes better with HDACis and which patient will benefit more from these epigenetic agents. 10.1080/13543784.2017.1386172
    I-7ab inhibited the growth of TNBC cells via targeting HDAC3 and promoting the acetylation of p53. Yang Mei,Dang Xuefei,Tan Yue,Wang Meixing,Li Xiaojing,Li Gang Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie Triple negative breast cancer (TNBC) is a heterogenous disease with high aggressive and poor outcome. The lack of biomarkers and targeted therapies makes it a challenge for the treatment of TNBC. Histone deacetylase inhibitors (HDACis) are emerging as novel anti-tumor agents in many types of human cancers. In this study, we found that I-7ab, a novel HDACi, inhibited the cell viability of TNBC cells and induced the cell apoptosis. Mechanistically, I-7ab specifically decreased the expression of HDAC3 and promoted the acetylation of p53 at both Lys373 and Lys382 amino acids. The up-regulated acetylation of p53 promoted the transcriptional activity of p53 and induced the expression of p21, which consequently caused cell cycle arrest at G1 phase. Administration of I-7ab inhibited the colony formation of TNBC cells. Collectively, these results indicated I-7ab as a promising anti-cancer agent in the treatment of TNBC. 10.1016/j.biopha.2018.01.063