The histone deacetylase inhibitor LBH589 enhances the anti-myeloma effects of chemotherapy in vitro and in vivo

Panobinostat (LBH589) is a potent histone deacetylase inhibitor (HDACi) that has shown anti-tumor activity in preclinical studies in both solid and hematological malignancies. We evaluated the anti-multiple myeloma (MM) effects of LBH589 alone and with melphalan or doxorubicin using MM cell lines and our human MM xenograft model LAGλ-1. LBH589 treatment resulted in increased acetylation of histones, induction of caspase cleavage, inhibition of cell proliferation and synergistic anti-MM effects with melphalan or doxorubicin in vitro. LBH589 with melphalan or doxorubicin also showed significantly enhanced anti-myeloma activity in vivo. These findings provide the basis for clinical development of these combination therapies.     

组蛋白乙酰化、甲基化调控异常在弥漫性大B细胞淋巴瘤中的意义

 目的　研究组蛋白H3（H3K9、H3K14）、H4（H4K5、H4K8、H4K12、H4K16）乙酰化、组蛋白H3K4、H3K9甲基化水平在弥漫性大B细胞淋巴瘤（DLBCL）细胞的表达意义及其相关性。方法　采用免疫组织化学SP法检测40例DLBCL,16例增生性淋巴结炎组织细胞中组蛋白H3、H4乙酰化水平、组蛋白H3K4、H3K9甲基化水平并进行分析和比较。结果　在DLBCL组中,乙酰化组蛋白H3、H4和甲基化组蛋白H3K4阳性高表达显著低于增生性淋巴结炎组;而甲基化组蛋白H3K9的阳性高表达则显著高于增生性淋巴结炎组（P＜0.05）,差异均有统计学意义。在DLBCL组,乙酰化组蛋白H3与乙酰化组蛋白H4、乙酰化组蛋白 H3与甲基化组蛋白H3K4、乙酰化组蛋白 H4与甲基化组蛋白H3K4的表达均有显著的相关性（P＜0.01）。结论　DLBCL存在组蛋白乙酰化及甲基化调控异常,可能是致病的重要因素之一。     

Global histone acetylation levels: Prognostic relevance in patients with renal cell carcinoma

Epigenetic alterations play an important role in carcinogenesis. Recent studies have suggested that global histone modifications are predictors of cancer recurrence in various tumor entities. Global histone acetylation levels (histone H3 lysine 9 acetylation [H3K9Ac], histone H3 lysine 18 acetylation [H3K18Ac], total histone H3 acetylation [H3Ac] and total histone H4 acetylation [H4Ac]) were determined in patients with renal cell carcinoma (RCC) using immunohistochemistry in a tissue micro array with 193 RCC and 10 oncocytoma specimens. The histone acetylation pattern was not different among the diverse histological subtypes of RCC or oncocytoma samples. The H3Ac levels were inversely correlated with pT‐stage (P = 0.005), distant metastasis (P = 0.036), Fuhrman grading (P = 0.001) and RCC progression (P = 0.029, hazard ratio 0.87). H4Ac deacetylation was correlated with pT‐stage (P = 0.011) and grading (P = 0.029). H3K18Ac levels were an independent predictor of cancer‐progression following surgery for localized RCC in the univariate (P = 0.001, hazard ratio 0.78) and multivariate (P = 0.005, hazard ratio 0.82) analysis. In conclusion, our study supports the concept of global histone modification levels as a universal cancer prognosis marker, and provides evidence for the use of histone deacetylases inhibitors as future drugs in the therapy of RCC. (Cancer Sci 2010; 101: 2664–2669)     

已被证实用于多药耐药性研究的一种新的多发性骨髓瘤细胞系

Objective:To find out how to overcome resistance during multiple myeloma (MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features. Methods:The parent cell line MOLP-2 was exposed to different concentrations of melphalan and a melphalan-resistant cell line MOLP-2/R was identified by continuous stepwise selection. The cell morphology and growth curves were examined. Protein levels of P-gp, MRP and FANCD2 monoubiquitination were checked by Western blotting. The IC50 of melphalan and resistance index (RI) were de-tected by MTT assay. Results:A melphalan-resistant cell line MOLP-2/R was finally identified. The RI of MOLP-2/R cells to melphalan was 6.03. Besides melphalan it was cross resistant to other chemotherapeutic agents, including ADM, CTX, DDP and VP-16. The multiplication time was postponed (P<0.05). Studies showed that FANCD2 protein monoubiquitination was enhanced, but the levels of P-gp and MRP expressions in the MOLP-2/R cells were similar with the parent calls. Conclusion:MOLP-2/R cell line may serve as an ideal model for exploring the mechanism of MDR. Over-expression of FANCD2 protein monoubiquitination might contribute to acquired drug resistance in MOLP-2/R celt line.     

The cellular level of histone H3 lysine 4 dimethylation correlates with response to adjuvant gemcitabine in Japanese pancreatic cancer patients treated with surgery

Background

To search for biomarkers identifying pancreatic cancer patients likely to benefit from adjuvant gemcitabine chemotherapy, we investigated the status of several histone modifications in pancreatic tumors and their relationship to clinicopathological features and outcomes.

Methods

Sixty one pancreatic cancer patients, primarily treated by surgical removal of tumors, were involved in the study. Thirty patients completed postoperative adjuvant gemcitabine, and in 31 it was discontinued. Tumor specimens were examined using immunohistochemistry for di- and tri-methylation of histone H3 lysine 4 (H3K4me2 and H3K4me3), dimethylation and acetylation of histone H3 lysine 9 (H3K9me2 and H3K9ac), and acetylation of histone H3 lysine 18 (H3K18ac). Positive tumor staining for each histone modification was used to classify patients into low- and high-staining groups, which were examined for relationships to clinicopathological features and clinical outcomes.

Results

High expression of H3K4me3 was related to the well and moderately differentiated tumor histological type (p = 0.012) and low expression of H3K4me2 was related to the presence of perineural invasion (p = 0.007). No cellular histone modifications were associated with overall or disease-free survival of patients as a whole. In the subgroup analyses, a low level of H3K4me2 was significantly associated with worse disease free survival in patients that completed adjuvant gemcitabine (p = 0.0239). Univariate and multivariate hazard models also indicated that a low level of H3K4me2 was a significant independent predictor of disease-free survival (p = 0.007).

Conclusion

H3K4me2 was found to be a predictor of response to adjuvant gemcitabine in Asian patients with pancreatic cancer.     

Synergistic induction of NY-ESO-1 antigen expression by a novel histone deacetylase inhibitor,valproic acid,with 5-aza-2′-deoxycytidine in glioma cells

NY-ESO-1, one of the most immunogenic cancer/testis antigens, provides attractive targets for cancer immunotherapy. NY-ESO-1 has been demonstrated to be expressed in a range of solid tumors via DNA demethylation and/or histone modification; however, it has been rarely expressed in glioma. The reversibility of these epigenetic aberrations is potentially attractive for glioma treatment with DNA-methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi), leading to reactivation of silenced genes. We previously demonstrated de novo induction of NY-ESO-1 in glioma cells by DNMTi. In this study, we show that an anticonvulsant, i.e., valproic acid (VPA), also acting as an HDACi, enhances induction of NY-ESO-1 in synergy with DNMTi. Chromatin assays demonstrated that combination of DNMTi and VPA elicited significant DNA demethylation, histone H3 Lys9 demethylation, and acetylation. These findings not only shed light on an epigenetic immunotherapy, but also suggest that the silencing of NY-ESO-1 is mediated by histone modification.     

Inhibition of the tumour necrosis factor-alpha autocrine loop enhances the sensitivity of multiple myeloma cells to anticancer drugs

Several autocrine soluble factors, including macrophage inflammatory protein-1α and tumour necrosis factor-alpha (TNF-α), promote the survival and growth of multiple myeloma (MM) cells. We hypothesised that inhibition of the TNF-α autocrine loop may enhance the cytotoxic effect of anticancer drugs in MM cell lines. In the present study, a TNF-α-neutralizing antibody suppressed cell proliferation and enhanced the cytotoxic effect of anticancer drugs on MM cells. In addition, combination treatment with the TNF-α-neutralizing antibody and the chemotherapy agent melphalan inhibited nuclear factor κB (NF-κB) p65 nuclear translocation and mammalian target of rapamycin (mTOR) activation and upregulated the expression of Bax and Bim. Treatment of ARH-77 cells with the NF-κB inhibitor dimethyl fumarate or the mTOR inhibitor rapamycin suppressed NF-κB p65 nuclear translocation and enhanced the cytotoxic effect of melphalan. Furthermore, infliximab, a monoclonal antibody against TNF-α, also enhanced the cytotoxic effect of anticancer drugs in ARH-77 cells. These results indicated that TNF-α-neutralizing antibodies or infliximab enhanced the cytotoxic effect of anticancer drugs by suppressing the TNF receptor/mTOR/NF-κB pathways. The inhibition of TNF-α may thus provide a new therapeutic approach to control tumour progression and bone destruction in MM patients.     

The global histone modification pattern correlates with overall survival in metachronous liver metastasis of colorectal cancer

Post-translational histone modifications are known to be altered in cancer tissues, and differences in the histone modification levels have recently been used to predict the clinical outcome in patients with certain types of cancer. In this study, we evaluated the immunohistochemical staining patterns of histone H3 dimethylation and acetylation in metachronous liver metastasis of colorectal carcinomas and examined its correlation with patient prognosis. Double 2?mm core tissue microarrays were made from 54 paraffin-embedded samples of liver metastasis from colorectal adenocarcinoma, and were examined by an immunohistochemical analysis of histone H3 lysine 4 (H3K4) dimethylation, histone, H3 lysine 9 (H3K9) dimethylation and histone H3 lysine 9 (H3K9) acetylation. Positive tumor cell staining for each histone modification was used to classify patients into low- and high-staining groups, which were then examined for correlations with the clinicopathological parameters and clinical outcome. Dimethylation of H3K4 correlated with the tumor histological type (P=0.043), and acetylation of H3K9 correlated with the tumor histological type (P=0.016). In addition, lower levels of H3K4 dimethylation correlated with a poor survival rate (P=0.035). The multivariate survival analysis showed that the H3K4 dimethylation status is an independent prognostic factor for colorectal cancer patients (P=0.011). We suggest that the pattern of histone modification as detected by immunohistochemistry may be an independent prognostic factor for metachronous liver metastasis of colorectal carcinomas.     

Effects of triptolide on histone acetylation and HDAC8 expression in multiple myeloma <Emphasis Type="Italic">in vitro</Emphasis>

Objective: Multiple myeloma is a kind of malignant plasma cell disease that originated from B lymphocyte and secrete great amount of monoclonal immunoglobulin. It is still one of the refractory diseases at present. Numerous studies show that there is an intensive relationship between the disequilibrium of histone acetylation and the occurance of multiple myeloma. Here we investigated the effect of triptolide(TPL) on the proliferation, apoptosis, histone H3 and H4 acetylation and expression of histone deacetylase 8 (HDAC8) in vitro, to explore its anti-myeloma mechanism.Methods: The effect of triptolide on the growth of RPMI8226 was studied by 3-(4,5-Dimethyl-2-thiazolyl) -2,5-diphenyl-2H-tetrazolium(MTT) assay. Apoptosis was detected by Hoechst 33258 staining. The protein expressions of acetyl-histone H3 and H4 were determined by Western blot, and the expression of HDAC8 was assessed by RT-PCR, Western blot and confocal microscopy.Results: Triptolide inhibited the proliferation of RPMI8226 and induced apoptosis in a time- and dose-dependent manner. The 36h IC50 value was (105.370±0.189)nmol/L. Triptolide increased the acetylation of histone H3 and H4 greatly. Furthermore, triptolide significantly down-regulated the mRNA and protein expression of HDAC8.Conclusion: Triptolide can inhibit proliferation and induce apoptosis of RPMI8226 significantly. Triptolide reduces the expression of HDAC8 in order to increase the histone H3 and H4 acetylation, which is possibly the anti-myeloma mechanism of triptolide.     

Selective depletion of human myeloma clonogenic stem cells from bone marrow cell preparations by a plasma-cell reactive antibody and complement

The monoclonal antibody MM4 reacts with human myeloma cells from plasma cell dyscrasia (PCD)-derived cell lines and bone marrow (BM) biopsies from PCD patients, but not with normal BM or peripheral blood mononuclear (PBM) cells. We examined cytotoxicity of MM4 and rabbit complement (MM4:C') on mixtures of normal BM mononuclear cells and myeloma cells from three different PCD-derived cell lines, RPMI 8226, GM 1312, or ARH-77. For cell preparations containing 10% myeloma cells, treatment with MM4 (500 micrograms per 10(5) cells, 4 degrees C, 60 min) and two cycles of complement (1:8, 23 degrees C, 2 x 30 min) consistently eliminated 2 logs or more of clonogenic myeloma stem cells, as determined by colony growth assays and limiting dilution analysis (99.4%, 98.9%, and 99.96% reduction of RPMI 8226, GM 1312, and ARH-77 cells, respectively). The majority of normal marrow progenitors were spared (inhibition of CFU-C: 10-13%; BFU-E: 0%). These observations suggest that MM4 may be useful for selective depletion of human myeloma clonogenic stem cells from bone marrow ex vivo.     

组蛋白去乙酰化酶抑制剂LBH589逆转多发性骨髓瘤细胞耐药机制的体外研究

 【摘要】　目的　探讨新一代组蛋白去乙酰化酶抑制剂LBH589作用于多发性骨髓瘤（MM）耐药细胞产生的相关基因表达变化,分析其逆转MM细胞耐药的机制。方法　采用Western blot法分析LBH589单药（0、20、50 nmol／L）及50 nmol／L LBH589联合5 μmol／L地塞米松作用MM1R细胞24 h后组蛋白 H4乙酰化的表达程度及bcl-X基因的表达变化。采用实时荧光定量PCR分析LBH589（0、20、50 nmol／L）及50 nmol／L LBH589联合5 μmol／L地塞米松分别作用MM1R细胞24、48 h后TOSO基因的表达变化。结果　Western blot分析显示不同浓度LBH589单药及联合地塞米松作用MM1R细胞24 h后随着药物浓度的升高,组蛋白 H4乙酰化的程度逐渐上调[（0.205±0.008）%、（0.346±0.009）%,（0.580±0.053）%、（0.986±0.012）%,F＝992.957,P＝0.032];bcl-X基因的表达则逐渐下调[（1.210±0.160）%、（0.930±0.036）%、（0.730±0.017）%、（0.488±0.029）%,F＝56.432,P＝0.028],变化呈剂量依赖性,且联合组的作用效果强于单药组（均P＜0.05）。实时荧光定量PCR分析显示不同浓度LBH589单药及联合地塞米松作用MM1R细胞24、48 h后随着药物浓度的增加和时间的延长,TOSO基因的表达逐渐下调[24 h：（1.00±0.00）%、（0.55±0.01）%、（0.47±0.01）%、（0.38±0.01）%,F＝1006.344,P＝0.040;48 h：（1.00±0.00）%、（0.39±0.04）%、（0.05±0.01）%、（0.03±0.00）%,F＝2383.977,P＝0.045],变化呈剂量-时间依赖性,且联合组的作用效果强于单药组（均P＜0.05）。结论　组蛋白去乙酰化酶抑制剂LBH589通过影响bcl-X及TOSO基因的表达,恢复MM1R对地塞米松的敏感性,促进组蛋白乙酰化,诱导细胞凋亡,达到治疗肿瘤的目的。     

Trichostatin A enhances radiosensitivity and radiation-induced DNA damage of esophageal cancer cells

BackgroundTrichostatin A (TSA) is emerging as a potential component of anticancer therapy. In this study, we aimed to identify the radiosensitizing effects of TSA in esophageal squamous carcinoma cell lines and identify the genomic alteration of histone acetylation associated with TSA treatment.MethodsEC109 and KYSE450 cells were pretreated with TSA (0.1 µM) for 12 hours prior to irradiation, and the cell viability, flow cytometry, and comet assays were performed to analyze cell growth, cell apoptosis, and DNA damage, respectively. Chromatin immunoprecipitation sequencing (ChIP-Seq) was performed to identify the acetylation sites of histone H3 lysine 9 (H3K9), which was altered by TSA.ResultsOur data showed that TSA could sensitize esophageal cancer cells to radiation by inducing cell cycle arrest and increasing cell apoptosis. DNA damage induced by radiation was enhanced by TSA treatment. In addition, a total of 105 differential peak-related genes were found to be associated with TSA treatment, which was identified using ChIP-Seq with specific antibodies against acetylated histone H3K9.ConclusionsOur data suggest that pretreatment with TSA can enhance ionizing radiation-induced DNA damage of esophageal cancer cells, which was associated with the altered histone modification of whole genome. TSA has potential implications for clinical use in increasing the anticancer efficacy of radiation.     

A novel selective small-molecule PI3K inhibitor is effective against human multiple myeloma in vitro and in vivo

Developing effective therapies against multiple myeloma (MM) is an unresolved challenge. Phosphatidylinositol-3-kinase (PI3K) activation may be associated with tumor progression and drug resistance, and inhibiting PI3K can induce apoptosis in MM cells. Thus, targeting of PI3K is predicted to increase the susceptibility of MM to anticancer therapy. The lead compound of a novel class of PI3K inhibitors, BAY80-6946 (IC₅₀=0.5 nM against PI3K-α), was highly efficacious in four different MM cell lines, where it induced significant antitumoral effects in a dose-dependent manner. The compound inhibited cell cycle progression and increased apoptosis (P<0.001 compared with controls). Moreover, it abrogated the stimulation conferred by insulin-like growth-factor-1, a mechanism relevant for MM progression. These cellular effects were paralleled by decreased Akt phosphorylation, the main downstream target of PI3K. Likewise, profound antitumoral activity was observed ex vivo, as BAY80-6946 significantly inhibited proliferation of freshly isolated myeloma cells from three patients (P<0.001 compared with vehicle). In addition, BAY80-6946 showed convincing in vivo activity against the human AMO-1 and MOLP-8 myeloma cell lines in a preclinical murine xenograft model, where treatment with 6 mg/kg every other day for 2 weeks reduced the cell numbers by 87.0% and 69.3%, respectively (P<0.001 compared with vehicle), without overt toxicity in treated animals.     

Future of Personalized Therapy Targeting Aberrant Signaling Pathways in Multiple Myeloma

Multiple myeloma (MM) is a genetically complex disease. Identification of mutations and aberrant signaling pathways that contribute to the progression of MM and drug resistance has potential to lead to specific targets and personalized treatment. Aberrant signal pathways include RAS pathway activation due to RAS or BRAF mutations (targeted by vemurafenib alone or combined with cobimetinib), BCL-2 overexpression in t(11:14) (targeted by venetoclax), JAK2 pathway activation (targeted by ruxolitinib), NF-κB pathway activation (treated with DANFIN combined with bortezomib), MDM2 overexpression, and PI3K/mTOR pathway activation (targeted by BEZ235). Cyclin D1 (CCND1) and MYC are also emerging as key potential targets. In addition, histone deacetylase inhibitors are already in use for the treatment of MM in combination therapy, and targeted inhibition of FGFR3 (AZD4547) is effective in myeloma cells with t(4;14) translocation. Bromodomain and extra terminal (BET) protein antagonists decrease the expression of MYC and have displayed promising antimyeloma activity. A better understanding of the alterations in signaling pathways that promote MM progression will further inform the development of precision therapy for patients.     

Troglitazone inhibits histone deacetylase activity in breast cancer cells

We previously demonstrated that the PPARγ agonist Troglitazone (TRG), a potent antiproliferative agent, in combination with the anthracycline antibiotic Doxorubicin (DOX), is an effective killer of multiple drug resistant (MDR) human cancer cells. Cell killing was accompanied by increased global histone H3 acetylation. Presently, we investigated the epigenetic and cell killing effects of TRG in estrogen receptor (ER) positive MCF7 breast cancer cells. MCF7 cells were treated with the Thiazolidinediones (TZDs) TRG and Ciglitazone (CIG), the non-TZD PPARγ agonist 15PGJ2, and the histone deacetylase inhibitors (HDACi’s) Trichostatin A (TSA), sodium butyrate and PXD101. Using MTT cell viability assays, Western analyzes and mass spectrometry, we showed a dose-dependent increase in cell killing in TRG and HDACi treated cells, that was associated with increased H3 lysine 9 (H3K9) and H3K23 acetylation, H2AX and H3S10 phosphorylation, and H3K79 mono- and di-methylation. These effects were mediated through an ER independent pathway. Using HDAC activity assays, TRG inhibited HDAC activity in cells and in cell lysates, similar to that observed with TSA. Furthermore, TRG and TSA induced a slower migrating HDAC1 species that was refractory to HDAC2 associations. Lastly, TRG and the HDACi’s decreased total and phosphorylated AKT levels. These findings suggest that TRG’s mode of killing may involve downregulation of PI3K signaling through HDAC inhibition, leading to increased global histone post-translational modifications.