Histone deacetylase inhibitor pre-treatment enhances the efficacy of DNA-interacting chemotherapeutic drugs in gastric cancer

A phase 2 study of chidamide in combination with CAG and venetoclax-azacitidine in acute myeloid leukemia: Clinical safety, efficacy, and correlative analysis

Acute myeloid leukemia (AML) is a highly heterogeneous hematopoietic malignancy characterized by elevated mortality. Epigenetic therapy plays an essential role in the treatment of AML. However, the clinical outcomes of the combination of multiple epigenetic agents and conventional chemotherapy remain unclear. We conducted a phase 2 study to evaluate the clinical safety and efficacy of chidamide combined with CAG and venetoclax-azacitidine (referred to as CACAG-VEN) in AML patients (NCT05659992). Patients received induction treatment with aclarubicin (10 mg/m2/d on days 1, 3, and 5), azacitidine (75 mg/m2 on days 1-7), cytarabine (75 mg/m2 bid on days 1-5), chidamide (30 mg, twice/week for 2 weeks), and venetoclax (100 mg on day 1, 200 mg on day 2, 400 mg on days 3-14). Granulocyte colony-stimulating factor 5 μg/kg/day was administered. After one cycle of CACAG-VEN, the overall response rate was 96.7 %, with a composite complete response (CRc) rate of 93.3 %. The CRc rates (86.7 %) were remarkable among patients with adverse NCCN risk. Patients receiving two cycles of CACAG-VEN achieved a CRc rate of 100 %. The 12-month overall survival rate was 69.7 %. The median time to recovery was 19 days for platelets ≥50,000/μL and 17 days for an absolute neutrophil count ≥500 cells/μL after induction therapy. The single-cell RNA sequence showed most immune cells exhibited no significant change in proportion after removing tumor cells. In conclusion, this regimen resulted in a high CRc rate in newly diagnosed AML patients, particularly in adverse-risk patients. And this regimen had minimal impact on immune cells.

Acquired vulnerability against EGF receptor inhibition in gastric cancer promoted by class I histone deacetylase inhibitor entinostat

INTRODUCTION

Histone deacetylase inhibitors (HDACi) have shown promising preclinical activity in gastric cancer cells; unfortunately, however, these could not be confirmed in clinical trials. This highlights the need for the identification of underlying reasons, which may also provide the basis for possible combination therapies. Here, we delineated the effects of HDACi on components of EGFR signalling in gastric cancer cells.

METHODS

We investigated entinostat effects on EGFR and amphiregulin (AREG) expression in various cell line- and primary patient tumor-based in vitro, ex vivo and in vivo models, on the mRNA and protein level. Based on these results, a combined entinostat plus EGFR inhibitor erlotinib treatment in vitro and in vivo was studied.

RESULTS

Proteomics analyses in gastric cancer cells treated with entinostat revealed a marked upregulation of EGFR in the majority of cell lines and an even more robust induction of the EGFR ligand AREG. This was confirmed in a panel of different cell lines in vitro, in tumor tissue-slice cultures ex vivo and in cell line- or patient-derived tumor xenografts in mice. Since previous studies in other tumor entities showed a downregulation of EGFR by HDACi, our findings thus indicate essential differences in the adaptive response of gastric carcinoma cells. Moreover, our results provided the basis for combined entinostat + EGFR inhibitor (erlotinib) treatment, and indeed we demonstrate synergistic effects in combination therapy studies.

CONCLUSION

Our findings establish the profound upregulation of the EGFR/AREG axis by entinostat as starting point for a rational combination therapy in gastric carcinoma.

Oxaliplatin activates P53/miR-34a/survivin axis in inhibiting the progression of gastric cancer cells

INTRODUCTION

The purpose of this research was to determine how the P53/microRNA-34a (miR-34a)/survivin pathway contributes to oxaliplatin-induced (L-OHP) cell inhibition in gastric cancer.

METHODS

The BGC-823 gastric cancer cells were selected, and we examined their viability following treatment with L-OHP at different concentrations and time periods. The expression levels of miR-34a, P53, and survivin in the cells were determined.

RESULTS

In the 12- and 24-h groups, drug concentration of 15 μg/cm² (p < .005 in both) significantly lowered cell viability. In comparison to the control group, miR-34a mRNA expression, P53 mRNA expression, and protein expression were all significantly greater in the 24-h group (p = .0324, p = .0069, p = .0260, respectively), but survivin mRNA and protein expressions were significantly lower than those in the control group (p = .0338, p = .0032, respectively). There was a significant decrease in gastric cancer cells in the miR-34a overexpression group (p = .0020), a significant increase in P53 mRNA and protein expression compared to the control group (p = .0080, p = .0121, respectively), and a significant decrease in survivin mRNA and protein expression compared to the control group. (p = .0213, p = .0069, respectively).

CONCLUSION

Oxaliplatin inhibits tumor growth, invasion, and metastasis by upregulating miR-34a, activating the expression of the upstream P53 gene, and driving the downregulation of survivin (P53/miR-34a/survivin axis) in BGC-823 gastric cancer cells.

Nanocarrier mediated entinostat and oxaliplatin combination therapy displayed enhanced efficacy against pancreatic cancer

Pancreatic cancer is the third leading cause of cancer-related death in the United States, with a 5-year survival rate of only 12%. The poor prognosis of pancreatic cancer is primarily attributed to the lack of early detection, the aggressiveness of the disease, and its resistance to conventional chemotherapeutics. The use of combination chemotherapy targeting different key pathways has emerged as a potential strategy to minimize drug resistance while improving therapeutic outcomes. Here, we evaluated a novel approach to treating pancreatic cancer using entinostat (ENT), a selective class I and IV HDAC inhibitor, and oxaliplatin (OXP) administered at considerably lower dosages. Combination therapy exhibited strong synergistic interaction against human (PANC-1) and murine (KPC) pancreatic cancer cells. As expected, ENT treatment enhanced acetylated histone H3 and H4 expression in treated cells, which was even augmented in the presence of OXP. Similarly, cells treated with a combination therapy showed higher expression of cleaved caspase 3 and increased apoptosis compared to monotherapy. To further improve the efficacy of the combination treatment, we encapsulated OXP and ENT into bovine serum albumin and poly(lactic-co-glycolic) acid nanoparticles. Both nanocarriers showed suitable physicochemical properties with respect to size, charge, polydispersity index, and loading. Besides, the combination of OXP and ENT nanoparticles showed similar or even better synergistic effects compared to free drugs during in vitro cytotoxicity and colony formation assays towards pancreatic cancer cells.

Role of Epigenetics for the Efficacy of Cisplatin

The clinical utility of the chemotherapeutic agent cisplatin is restricted by cancer drug resistance, which is either intrinsic to the tumor or acquired during therapy. Epigenetics is increasingly recognized as a factor contributing to cisplatin resistance and hence influences drug efficacy and clinical outcomes. In particular, epigenetics regulates gene expression without changing the DNA sequence. Common types of epigenetic modifications linked to chemoresistance are DNA methylation, histone modification, and non-coding RNAs. This review provides an overview of the current findings of various epigenetic modifications related to cisplatin efficacy in cell lines in vitro and in clinical tumor samples. Furthermore, it discusses whether epigenetic alterations might be used as predictors of the platinum agent response in order to prevent avoidable side effects in patients with resistant malignancies. In addition, epigenetic targeting therapies are described as a possible strategy to render cancer cells more susceptible to platinum drugs.

Mitochondrial dysfunction and chromatin changes with autophagy-mediated survival in doxorubicin resistant cancer cell lines

Acquired chemoresistance against doxorubicin remains an obstacle in long-term treatment. The comprehensive molecular mechanism underlying the acquirement of doxorubicin resistance has not been reported. The objective of the present study is to understand the survival strategies and investigate alternate treatments for doxorubicin-resistant cervical and liver cancer cells. In this study, doxorubicin-resistant sublines were established by continuous incremental exposure of the drug to parental cervical and liver cancer cells. The transcriptome data in drug-resistant model revealed downregulated energy production pathways like glycolysis, oxidative phosphorylation, and mTOR signalling. This resulted in slow proliferation and altered mitochondrial changes in doxorubicin-resistant cells. The altered metabolic state of the resistant cells was associated with hypo-acetylation of chromatin. Pre-treatment with HDACi sensitized the drug-resistant cells to doxorubicin by increased drug accumulation in the cells, thereby leading to apoptosis. Additionally, we demonstrated that autophagy gets activated in doxorubicin-resistant cervical and liver cancer cells. Autophagy acts as pro-survival mechanism in resistant cells, as inhibition of autophagy leads to cell death. In conclusion, the data highlights survival ability of resistant cells with mitochondrial dysfunction, altered chromatin state, and pro-survival autophagy. The study proposes targeting chromatin alteration with the combinatorial treatment of HDACi with doxorubicin or survival mechanism through autophagy inhibitor against doxorubicin-resistant cancer phenotype.

Repression of the PRELP gene is relieved by histone deacetylase inhibitors through acetylation of histone H2B lysine 5 in bladder cancer

BACKGROUND

Proline/arginine-rich end leucine-rich repeat protein (PRELP) is a member of the small leucine-rich proteoglycan family of extracellular matrix proteins, which is markedly suppressed in the majority of early-stage epithelial cancers and plays a role in regulating the epithelial-mesenchymal transition by altering cell-cell adhesion. Although PRELP is an important factor in the development and progression of bladder cancer, the mechanism of PRELP gene repression remains unclear.

RESULTS

Here, we show that repression of PRELP mRNA expression in bladder cancer cells is alleviated by HDAC inhibitors (HDACi) through histone acetylation. Using ChIP-qPCR analysis, we found that acetylation of lysine residue 5 of histone H2B in the PRELP gene promoter region is a marker for the de-repression of PRELP expression.

CONCLUSIONS

These results suggest a mechanism through which HDACi may partially regulate the function of PRELP to suppress the development and progression of bladder cancer. Some HDACi are already in clinical use, and the findings of this study provide a mechanistic basis for further investigation of HDACi-based therapeutic strategies.

Inhibition of HDACs Suppresses Cell Proliferation and Cell Migration of Gastric Cancer by Regulating E2F5 Targeting BCL2

(1) Background: Gastric cancer (GC) is the most common high death-rate cancer type worldwide, with an enhanced prevalence and increased rate of mortality. Although significant evidence on surgery strategy has been generated for the treatment of GC, conclusions are still uncertain regarding profound metastatic or persevering gastric cancer. Therefore, it is essential to develop novel and effective biomarkers or therapeutic targets for the diagnosis of GC. Histone deacetylations (HDACs) are important epigenetic regulators that control the aberrant transcription of critical genes that are mainly involved in cell proliferation, cell migration, regulation of the cell cycle, and different signal pathways. (2) Methods: Expression analysis of HDACs family members and E2F5 in gastric cancer cell lines was determined by RT-PCR and Western blotting. The cell proliferation was determined through an MTT assay. Cell migration was determined using a wound-healing assay. Flow cytometry experiments were used to determine cell-cycle analysis. The statistical software OriginPro 2015 (OriginLab, Northampton, MA, USA) was used to analyze data. A p value of < 0.05 was regarded as significant. (3) Results: The present study shows that E2F5 expression is upregulated in GC cancer cell lines compared to normal cell lines, and is positively associated with the level of HDACs and BCL2. HDACi and knocking down of E2F5 as tumor suppressors inhibited cell proliferation, migration invasion, and blocked the cell cycle in gastric cancer cells by suppressing BCL2. The results conclude that the anticancer mechanism of HDACi was determined by regulating E2F5 via targeting BCL2. (4) Conclusions: Our results suggest that the HDAC–E2F5–BCL2 signaling axis might be a novel potential biomarker in gastric cancer.

Hepatocellular carcinoma: Understanding molecular mechanisms for defining potential clinical modalities

Liver cancer is the sixth most commonly occurring cancer and costs millions of lives per year. The diagnosis of hepatocellular carcinoma (HCC) has relied on scanning techniques and serum-based markers such as α-fetoprotein. These measures have limitations due to their detection limits and asymptomatic conditions during the early stages, resulting in late-stage cancer diagnosis where targeted chemotherapy or systemic treatment with sorafenib is offered. However, the aid of conventional therapy for patients in the advanced stage of HCC has limited outcomes. Thus, it is essential to seek a new treatment strategy and improve the diagnostic techniques to manage the disease. Researchers have used the omics profile of HCC patients for sub-classification of tissues into different groups, which has helped us with prognosis. Despite these efforts, a promising target for treatment has not been identified. The hurdle in this situation is genetic and epigenetic variations in the tumor, leading to disparities in response to treatment. Understanding reversible epigenetic changes along with clinical traits help to define new markers for patient categorization and design personalized therapy. Many clinical trials of inhibitors of epigenetic modifiers (also known as epi-drugs) are in progress. Epi-drugs like azacytidine or belinostat are already approved for other cancer treatments. Furthermore, epigenetic changes have also been observed in drug-resistant HCC tumors. In such cases, combinatorial treatment of epi-drugs with systemic therapy or trans-arterial chemoembolization might re-sensitize resistant cells.

Signet ring cell cancer of stomach and gastro-esophageal junction: molecular alterations, stage-stratified treatment approaches, and future challenges

Purpose

There has been an increase in the incidence of signet ring cell cancer (SRCC) of the stomach and gastro-esophageal junction (GEJ). The multistage carcinogenesis involving genetic and epigenetic aberrations may have a major role in the increasing incidence of SRCC. Although there are numerous studies on the prognostic value of SRCC, they are markedly inconsistent in their results, making it impossible to draw any meaningful conclusions. We aimed to examine the available evidences on molecular alterations and stage-stratified treatment approaches in SRCC of the stomach and GEJ.

Methods

A systematic search was carried out in PubMed. Studies available in English related to SRCC of stomach and gastro-esophageal junction were identified and evaluated.

Results

This study reviewed the current evidence and provided an insight into the molecular alterations, stage-stratified treatment approaches, and future challenges in the management of SRCC of the stomach and GEJ. Specific therapeutic strategies and personalized multimodal treatment have been recommended based on the tumor characteristics of SRCC.

Conclusion

Multistage carcinogenesis involving genetic and epigenetic aberrations in SRCC is interlinked with stage-dependent prognosis. Specific therapeutic strategy and personalized multimodal treatment should be followed based on the tumor characteristics of SRCC. Endoscopic resection, radical surgery, and perioperative chemotherapy should be offered in carefully selected patients based on stage and prognostic stratification. Future studies in genetic and molecular analysis, histopathological classification, and options of multimodality treatment will improve the prognosis and oncological outcomes in SRCC of gastric and GEJ.

Potential new targets and drugs related to histone modifications in glioma treatment

Glioma accounts for 40-50% of craniocerebral tumors, whose outcome rarely improves after standard treatment. The development of new therapeutic targets for glioma treatment has important clinical significance. With the deepening of research on gliomas, recent researchers have found that the occurrence and development of gliomas is closely associated with histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination. Additionally, evidence has confirmed the close relationship between histone modifications and temozolomide (TMZ) resistance. Therefore, histone modification-related proteins have been widely recognized as new therapeutic targets for glioma treatment. In this review, we summarize the potential histone modification-associated targets and related drugs for glioma treatment. We have further clarified how histone modifications regulate the pathogenesis of gliomas and the mechanism of drug action, providing novel insights for the current clinical glioma treatment. Herein, we have also highlighted the limitations of current clinical therapies and have suggested future research directions and expected advances in potential areas of disease prognosis. Due to the complicated glioma pathogenesis, in the present review, we have acknowledged the limitations of histone modification applications in the related clinical treatment.

Epigenetics and therapeutic targets in gastrointestinal malignancies

Gastrointestinal (GI) malignancies account for substantial mortality and morbidity worldwide. They are generally promoted by dysregulated signal transduction and epigenetic pathways, which are controlled by specific enzymes. Recent studies demonstrated that histone deacetylases (HDACs) together with DNA methyltransferases (DNMTs) have crucial roles in the signal transduction/epigenetic pathways in GI regulation. In this review, we discuss various enzyme targets and their functional mechanisms responsible for the regulatory processes of GI malignancies. We also discuss the epigenetic therapeutic targets that are mainly facilitated by DNMT and HDAC inhibitors, which have functional consequences and clinical outcomes for GI malignancies.

Epigenetic Mechanisms in Gastric Cancer: Potential New Therapeutic Opportunities

Gastric cancer (GC) is one of the deadliest malignancies worldwide. Complex disease heterogeneity, late diagnosis, and suboptimal therapies result in the poor prognosis of patients. Besides genetic alterations and environmental factors, it has been demonstrated that alterations of the epigenetic machinery guide cancer onset and progression, representing a hallmark of gastric malignancies. Moreover, epigenetic mechanisms undergo an intricate crosstalk, and distinct epigenomic profiles can be shaped under different microenvironmental contexts. In this scenario, targeting epigenetic mechanisms could be an interesting therapeutic strategy to overcome gastric cancer heterogeneity, and the efforts conducted to date are delivering promising results. In this review, we summarize the key epigenetic events involved in gastric cancer development. We conclude with a discussion of new promising epigenetic strategies for gastric cancer treatment.