Chidamide Inhibits Aerobic Metabolism to Induce Pancreatic Cancer Cell Growth Arrest by Promoting Mcl-1 Degradation

Chidamide enhances T-cell-mediated anti-tumor immune function by inhibiting NOTCH1/NFATC1 signaling pathway in ABC-type diffuse large B-cell lymphoma

Chidamide (CS055/HBI-8000, tucidinostat) has shown promising effects in the clinical treatment of various hematologic tumors. Diffuse large B-cell lymphoma (DLBCL) has shown highly heterogeneous biological characteristics. There are complex mechanisms of the role of chidamide in DLBCL for in-depth study. It is essential to probe further into the mechanism of drug-tumor interactions as a guide to clinical application and to understand the occurrence and progression of DLBCL. In vitro and in vivo models were utilized to determine the effects of chidamide on signaling pathways involved in the DLBCL tumor microenvironment. The experimental results show that chidamide inhibited the proliferation of DLBCL cell lines in a dose- and time-dependent manner, and down-regulated the expression of NOTCH1 and NFATC1 in DLBCL cells as well as decreased the concentration of IL-10 in the supernatant. In addition, chidamide significantly lowered the expression of PD1 or TIM3 on CD4+T cells and CD8+T cells and elevated the levels of IL-2, IFN-γ, and TNF-α in the serum of animal models, which augmented the function of circulating T cells and tumor-infiltrating T cells and ultimately significantly repressed the growth of tumors. These findings prove that chidamide can effectively inhibit the cell activity of DLBCL cell lines by inhibiting the activation of NOTCH1 and NFATC1 signaling pathways. It can also improve the abnormal DLBCL microenvironment in which immune escape occurs, and inhibit immune escape. This study provides a new therapeutic idea for the exploration of individualized precision therapy for patients with malignant lymphoma.

[Chidamide inhibits proliferation and promotes apoptosis of esophageal squamous cell carcinoma cells by inhibiting the PI3K/Akt and ERK1/2 pathways and increasing DNA damage]

OBJECTIVE

To investigate the mechanism mediating the inhibitory effect of chidamide on esophageal squamous cell carcinoma (ESCC) cells.

METHODS

ESCC cell lines KYSE-150, KYSE-450 and KYSE-510 were treated with 5, 10, 20, or 40 μmol/L of chidamide, and the changes in cell proliferation, colony-forming capacity, cell apoptosis and cell cycle were assessed using MTT aasay, colony formation experiment and flow cytometry. Western blotting was performed to detect the expression levels of cleaved caspase-3, cleaved PARP, p21, cyclin D1, p-Akt, p-ERK1/2, γH2AX, H3K9ac, and Ki-67. In a nude mouse model bearing subcutaneous ESCC xenografts, the effects of intraperitoneal injection of 20 mg/kg chidamide for 3 days on tumor size and body weight were observed every 3 days, and Ki-67 and CD31 expressions in the tumor tissues were detected using immunohistochemistry. Tubular formation experiment was used to examine the effect of chidamide on tubular formation of human umbilical vein endothelial cells (HUVECs) in vitro.

RESULTS

In cultured ESCC cell lines, chidamide significantly inhibited cell proliferation and colony formation (P < 0.05), promoted cell apoptosis, and increased the percentage of G0/G1 phase cells (all P < 0.01). Chidamide obviously up-regulated cleaved caspase-3, cleaved PARP, p21, γH2AX, and H3K9ac and down-regulated cyclin D1, p-Akt and p-ERK1/2, and Ki-67 in the cells (P < 0.01). In the tumor-bearing mouse models, treatment with chidamide significantly reduced the tumor volume (P < 0.05), tumor to body weight ratio (P < 0.01), and the expression levels of Ki-67 and CD31 in the tumors (P < 0.01). Chidamide also significantly inhibited tubule formation in cultured HUVECs (P < 0.05).

CONCLUSION

Chidamide inhibits proliferation, induces apoptosis and blocks cell cycle of ESCC cells possibly by inhibiting the PI3K/Akt and ERK1/2 pathways and increasing DNA damage. Chidamide also inhibits subcutaneous tumorigenesis of ESCC cells in mice by inhibiting tumor cell proliferation and angiogenesis.

Therapeutic potential of tucidinostat, a subtype-selective HDAC inhibitor, in cancer treatment

Histone deacetylase (HDAC) is one of the most characterized epigenetic modifiers, modulating chromatin structure and gene expression, which plays an important role in cell cycle, differentiation and apoptosis. Dysregulation of HDAC promotes cancer progression, thus inhibitors targeting HDACs have evidently shown therapeutic efficacy in multiple cancers. Tucidinostat (formerly known as chidamide), a novel subtype-selective HDAC inhibitor, inhibits Class I HDAC1, HDAC2, HDAC3, as well as Class IIb HDAC10. Tucidinostat is approved in relapsed or refractory (R/R) peripheral T-cell lymphoma (PTCL), advanced breast cancer and R/R adult T-cell leukemia-lymphoma (ATLL). Compared with other HDAC inhibitors, tucidinostat shows notable antitumor activity, remarkable synergistic effect with immunotherapy, and manageable toxicity. Here, we comprehensively summarize recent advances in tucidinostat as both monotherapy and a regimen of combination therapy in both hematological and solid malignancies in clinic. Further studies will endeavor to identify more combination strategies with tucidinostat and to identify specific clinical biomarkers to predict the therapeutic effect.

Chidamide Suppresses the Growth of Cholangiocarcinoma by Inhibiting HDAC3 and Promoting FOXO1 Acetylation

Inhibitors for histone deacetylases (HDACs) have been identified as epigenetic drug targets to treat a variety of malignancies through several molecular mechanisms. The present study is aimed at investigating the mechanism underlying the possible antitumor effect of the HDAC inhibitor chidamide (CDM) on cholangiocarcinoma (CCA). Microarray-based gene expression profiling was conducted to predict the expression of HDACs in CCA, which was validated in clinical tissue samples from CCA patients. Next, the proliferation, migration, invasion, autophagy, and apoptosis of human CCA QBC939 and SNU308 cells were measured following treatment with CDM at different concentrations. The acetylation level of FOXO1 in the nucleus and cytoplasm of QBC939 and SNU308 cells was determined after overexpression and suppression of HDAC3. A QBC939-implanted xenograft nude mouse model was established for further exploration of CDM roles in vitro. HDAC3 was prominently expressed in CCA tissues and indicated a poor prognosis for patients with CCA. CDM significantly inhibited cell proliferation, migration, and invasion of QBC939 and SNU308 cells, while inducing their autophagy and apoptosis by reducing the expression of HDAC3. CDM promoted FOXO1 acetylation by inhibiting HDAC3, thereby inducing cell autophagy. Additionally, CDM inhibited tumor growth in vivo via HDAC3 downregulation and FOXO1 acetylation induction. Overall, this study reveals that CDM can exhibit antitumor effects against CCA by promoting HDAC3-mediated FOXO1 acetylation, thus identifying a new therapeutic avenue for the treatment of CCA.

Histone deacetylases: A novel class of therapeutic targets for pancreatic cancer

Pancreatic cancer is the seventh leading cause of cancer death worldwide, with a low 5-year survival rate. Novel agents are urgently necessary to treat the main pathological type, known as pancreatic ductal carcinoma (PDAC). The dysregulation of histone deacetylases (HDACs) has been identified in association with PDAC, which can be more easily targeted by small molecular inhibitors than gene mutations and may represent a therapeutic breakthrough for PDAC. However, the contributions of HDACs to PDAC remain controversial, and pharmacokinetic challenges have limited the application of HDAC inhibitors (HDACis) in PDAC. This review summarizes the mechanisms associated with success and failure of HDACis in PDAC and discusses the recent progress made in HDACi development and application, such as combination therapies designed to enhance efficacy. More precise strategies involving HDACis might eventually improve the outcomes of PDAC treatment.

Therapeutic Interaction of Apatinib and Chidamide in T-Cell Acute Lymphoblastic Leukemia through Interference with Mitochondria Associated Biogenesis and Intrinsic Apoptosis

T-cell acute lymphoblastic leukemia (T-ALL) shows poor clinical outcome and has limited therapeutic options, indicating that new treatment approaches for this disease are urgently required. Our previous study demonstrated that apatinib, an orally selective VEGFR-2 antagonist, is highly effective in T-ALL. Additionally, chidamide, a histone deacetylase inhibitor, has proven to be cytotoxic against T-ALL in preclinical and clinical settings. However, whether the therapeutic interaction of apatinib and chidamide in T-ALL remains unknown. In this study, apatinib and chidamide acted additively to decrease cell viability and induce apoptosis in T-ALL in vitro. Notably, compared with apatinib or chidamide alone, the combinational regimen was more efficient in abrogating the leukemia burden in the spleen and bone marrow of T-ALL patient-derived xenograft (PDX) models. Mechanistically, the additive antileukemia effect of apatinib and chidamide was associated with suppression of mitochondrial respiration and downregulation of the abundance levels of several rate-limiting enzymes that are involved in the citric acid cycle and oxidative phosphorylation (OXPHOS). In addition, apatinib enhanced the antileukemia effect of chidamide on T-ALL via activation of the mitochondria-mediated apoptosis pathway and impediment of mitochondrial biogenesis. Taken together, the study provides a potential role for apatinib in combination with chidamide in the management of T-ALL and warrants further clinical evaluations of this combination in patients with T-ALL.

The epigenetic immunomodulator, HBI-8000, enhances the response and reverses resistance to checkpoint inhibitors

Background

Treatment with immune checkpoint inhibitors (ICIs) targeting CTLA-4 and the PD-1/PD-L1 axis is effective against many cancer types. However, due in part to unresponsiveness or acquired resistance, not all patients experience a durable response to ICIs. HBI-8000 is a novel, orally bioavailable class I selective histone deacetylase inhibitor that directly modifies antitumor activity by inducing apoptosis, cell cycle arrest, and resensitization to apoptotic stimuli in adult T cell lymphoma patients. We hypothesized that HBI-8000 functions as an epigenetic immunomodulator to reprogram the tumor microenvironment from immunologically cold (nonresponsive) to hot (responsive).

Method

Mice bearing syngeneic tumors (MC38 and CT26 murine colon carcinoma and A20 B-cell lymphoma were treated daily with HBI-8000 (orally), alone or in combination with PD-1, PD-1 L, or CTLA-4 antibodies. MC38 tumors were also analyzed in nanoString gene expression analysis.

Results

HBI-8000 augmented the activity of ICI antibodies targeting either PD-1, PD-L1 or CTLA-4, and significantly increased tumor regression (p < 0.05) in the above models. Gene expression analysis of the treated MC38 tumors revealed significant changes in mRNA expression of immune checkpoints, with enhanced dendritic cell and antigen-presenting cell functions, and modulation of MHC class I and II molecules.

Conclusions

These findings suggest that HBI-8000 mediates epigenetic modifications in the tumor microenvironment, leading to improved efficacy of ICIs, and provide strong rationale for combination therapies with ICIs and HBI-8000 in the clinical setting.

Precis

As an HDACi, HBI-8000 plays an important role in priming the immune system in the tumor microenvironment. The current preclinical data further justifies testing combination of HBI-8000 and ICIs in the clinic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08702-x.

Chidamide increases the sensitivity of refractory or relapsed acute myeloid leukemia cells to anthracyclines via regulation of the HDAC3 -AKT-P21-CDK2 signaling pathway

BACKGROUND

Induction therapy for acute myeloid leukemia (AML) is an anthracycline-based chemotherapy regimen. However, many patients experience a relapse or exhibit refractory disease (R/R). There is an urgent need for more effective regimens to reverse anthracycline resistance in these patients.

METHODS

In this paper, Twenty-seven R/R AML patients with anthracycline resistance consecutively received chidamide in combination with anthracycline-based regimen as salvage therapy at the Chinese PLA General Hospital.

RESULTS

Of the 27 patients who had received one course of salvage therapy, 13 achieved a complete response and 1 achieved a partial response. We found that the HDAC3-AKT-P21-CDK2 signaling pathway was significantly upregulated in anthracycline-resistant AML cells compared to non-resistant cells. AML patients with higher levels of HDAC3 had lower event-free survival (EFS) and overall survival (OS) rates. Moreover, anthracycline-resistant AML cells are susceptible to chidamide, a histone deacetylase inhibitor which can inhibit cell proliferation, increase cell apoptosis and induce cell-cycle arrest in a time- and dose-dependent manner. Chidamide increases the sensitivity of anthracycline-resistant cells to anthracycline drugs, and these effects are associated with the inhibition of the HDAC3-AKT-P21-CDK2 signaling pathway.

CONCLUSION

Chidamide can increase anthracycline drug sensitivity by inhibiting HDAC3-AKT-P21-CDK2 signaling pathway, thus demonstrating the potential for application.

Chidamide Inhibits Acute Myeloid Leukemia Cell Proliferation by lncRNA VPS9D1-AS1 Downregulation via MEK/ERK Signaling Pathway

Irregular histone modification and aberrant lncRNAs expression are closely related to the occurrence of tumors including acute myeloid leukemia (AML). However, the effects and specific underlying molecular mechanism of histone deacetylase inhibitors on lncRNA expression in AML cells are unclear. Here, we reported the effects of a novel histone deacetylase inhibitor Chidamide on proliferation and lncRNA expression in AML cells. Chidamide inhibited cell proliferation, blocked G1/S phase transition, and induced cell apoptosis through the caspase-dependent apoptotic pathway in AML cells. Chidamide also inhibited the formation of subcutaneous tumors. Transcriptome sequencing results showed that 1,195 lncRNAs were co-upregulated and 780 lncRNAs were co-downregulated after Chidamide treatment of SKM-1 cells and THP-1 cells. Combined with transcriptome sequencing data and the gene expression profiling interactive analysis dataset, we found that VPS9D1-AS1 expression was negatively correlated with the survival of AML patients. VPS9D1-AS1 knockdown inhibited cell proliferation, arrested cell cycle, as well as inhibited the formation of subcutaneous tumors in vivo. VPS9D1-AS1 overexpression had the reverse effect. Furthermore, VPS9D1-AS1 knockdown inhibited the MEK/ERK signaling pathway, and thus enhanced the inhibitory effect of Chidamide on AML cell proliferation. These findings suggested that targeted regulation of VPS9D1-AS1 might overcome the limitations of Chidamide in the treatment of AML.

BDA-366, a putative Bcl-2 BH4 domain antagonist, induces apoptosis independently of Bcl-2 in a variety of cancer cell models

Several cancer cell types, including chronic lymphocytic leukemia (CLL) and diffuse large B-cell lymphoma (DLBCL) upregulate antiapoptotic Bcl-2 to cope with oncogenic stress. BH3 mimetics targeting Bcl-2's hydrophobic cleft have been developed, including venetoclax as a promising anticancer precision medicine for treating CLL patients. Recently, BDA-366 was identified as a small molecule BH4-domain antagonist that could kill lung cancer and multiple myeloma cells. BDA-366 was proposed to switch Bcl-2 from an antiapoptotic into a proapoptotic protein, thereby activating Bax and inducing apoptosis. Here, we scrutinized the therapeutic potential and mechanism of action of BDA-366 in CLL and DLBCL. Although BDA-366 displayed selective toxicity against both cell types, the BDA-366-induced cell death did not correlate with Bcl-2-protein levels and also occurred in the absence of Bcl-2. Moreover, although BDA-366 provoked Bax activation, it did neither directly activate Bax nor switch Bcl-2 into a Bax-activating protein in in vitro Bax/liposome assays. Instead, in primary CLL cells and DLBCL cell lines, BDA-366 inhibited the activity of the PI3K/AKT pathway, resulted in Bcl-2 dephosphorylation and reduced Mcl-1-protein levels without affecting the levels of Bcl-2 or Bcl-xL. Hence, our work challenges the current view that BDA-366 is a BH4-domain antagonist of Bcl-2 that turns Bcl-2 into a pro-apoptotic protein. Rather, our results indicate that other mechanisms beyond switching Bcl-2 conformation underlie BDA-366's cell-death properties that may implicate Mcl-1 downregulation and/or Bcl-2 dephosphorylation.

High Expression of Succinate Dehydrogenase Subunit A Which Is Regulated by Histone Acetylation, Acts as a Good Prognostic Factor of Multiple Myeloma Patients

Most patients with multiple myeloma (MM) will eventually relapse and current treatments have limited effect. Herein, we demonstrate that succinate dehydrogenase subunit A (SDHA) was low expressed in MM patients, and patients with SDHA relatively high expression had long overall survival and progression-free survival. Furthermore, SDHA high expression inhibited proliferation and invasion in MM cell lines and enhanced the anti-tumor and synergistic effect of chemotherapeutics. More importantly, chidamide was proved effective in MM by targeting SDHA, and expression of SDHA was increased by chidamide through acetylating H3K27 site of SDHA. Collectively, high expression of SDHA, which was regulated by histone acetylation and targeted by chidamide, might become a good prognostic factor of MM patients.

Chidamide acts on the histone deacetylase-mediated miR-34a/Bcl-2 axis to regulate NB4 cell line proliferation and apoptosis

Acute promyelocytic leukemia (APL), a biologically and clinically distinct variant of acute myelogenous leukemia, is characterized by the fusion of the N-terminus of promyelocytic leukemia protein to the C terminus of retinoic acid receptor alpha, mostly due to chromosomal translocation t(15;17). Chidamide, a synthetic analogue of MS-275 identified from a group of benzamide-type compounds, has been found to have efficient anticancer activity in basic and clinical research studies. However, the concrete role and underlying mechanism of Chidamide in the treatment of APL has not been well characterized. Our data demonstrate that Chidamide inhibited the expression of histone deacetylase (HDAC) to induce apoptosis and suppress proliferation in NB4 cells. Mechanistically, Chidamide increases the expression of miR-34a by suppressing HDAC. Furthermore, B-cell lymphoma-2 (Bcl-2) is a direct target of miR-34a, the expression of which is regulated by miR-34a. Functionally, Chidamide inhibits cell proliferation and promotes apoptosis through miR-34a/Bcl-2. Chidamide exerts its anticancer effect via the HDAC-mediated miR-34a/Bcl-2 axis, providing potential targets for APL therapy.

Chidamide Inhibits Glioma Cells by Increasing Oxidative Stress via the miRNA-338-5p Regulation of Hedgehog Signaling

Objective

Chidamide has a broad spectrum of antitumor activity but its function on glioma remains unknown. The increase of reactive oxygen species (ROS) and reactive nitrogen species (RNS) may control glioma risk by promoting its apoptosis and necrosis. Hedgehog pathway is crucial to glioma cell proliferation and controls ROS production. We aimed to explore the effects of chidamide on the levels of miR-338-5p (glioma cell inhibitor), which may regulate Hedgehog signaling, resulting in the changes of RNS. Materials and Methods. Migration and invasion activities of glioma cells were measured by using the Transwell chamber assay. The expression levels of Sonic Hedgehog (Shh), Indian Hedgehog (Ihh), Desert Hedgehog (Dhh), miR-338-5p, and related molecules were detected by using real-time PCR (RT-PCR) and or Western Blot in U87 and HS683 glioma cells. The effects of chidamide on these molecules were measured by using the miR-338-5p inhibitor or mimics in U87 and HS683 glioma cell lines. ROS and RNS were measured by DCF DA and DAF-FM DA fluorescence. Biomarkers of oxidative stress were measured by using a corresponding kit. Apoptosis and necrosis rates were measured by using flow cytometry.

Results

Chidamide inhibited the growth rate, migration, and invasion of human malignant glioma cells and increased the level of miR-338-5p. miR-338-5p inhibitor or mimics increased or inhibited the growth rate of U87 and HS683 glioma cells. Chidamide inhibited the levels of Shh, Ihh, migration protein E-cadherin, and invading protein MMP-2. The increase in the level of Shh and Ihh led to the reduction in the ROS and RNS levels. miR-338-5p inhibitor or mimics also showed a promoting or inhibitory function for the levels of Shh and Ihh. Furthermore, miR-338-5p mimics and inhibitor inhibited or promoted the migration and invasion of the glioma cells (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (

Conclusion

Chidamide inhibits glioma cells by increasing oxidative stress via the miRNA-338-5p regulation of Hedgehog signaling. Chidamide may be a potential drug in the prevention of glioma development.

Proteasome inhibitor MG132 suppresses pancreatic ductal adenocarcinoma-cell migration by increasing ESE3 expression

The clinical significance of the proteasome inhibitor MG132 has been examined in numerous human cancer types; however, its influence on the metastasis and progression of pancreatic cancer is yet to be determined. In the present study, the effect of MG132 treatment on pancreatic ductal adenocarcinoma (PDAC) cell lines (SW1990 and PANC-1) was examined. Compared with the control groups, MG132 treatment resulted in higher expression levels of ETS homologous factor (ESE3), a crucial member of the E26 transformation-specific family that is central to various differentiation and development processes in epithelial tissues. MG132 treatment also increased the nuclear translocation of ESE3. Mechanistically, MG132 further inhibited the invasion and migration of PDAC cells by promoting E-cadherin expression, which not only plays an important role in cell-cell adhesion, but is also a direct target of ESE3. Furthermore, subsequent knockdown experiments, using short interfering RNAs, demonstrated that MG132 upregulated E-cadherin via an increase in ESE3 expression. The results of the present study support the hypothesis that MG132 treatment inhibits PDAC metastasis, highlighting the potential of MG132 as a therapeutic agent for the treatment of patients with PDAC.

Chidamide, a histone deacetylase inhibitor, induces growth arrest and apoptosis in multiple myeloma cells in a caspase-dependent manner

Chidamide, a novel histone deacetylase (HDAC) inhibitor, induces antitumor effects in various types of cancer. The present study aimed to evaluate the cytotoxic effect of chidamide on multiple myeloma and the underlying mechanisms involved. Viability of multiple myeloma cells upon chidamide treatment was determined by the Cell Counting Kit-8 assay. Apoptosis induction and cell cycle alteration were detected by flow cytometry. Specific apoptosis-associated proteins and cell cycle proteins were evaluated by western blot analysis. Chidamide suppressed cell viability in a time- and dose-dependent manner. Chidamide treatment markedly suppressed the expression of type I HDACs and further induced the acetylation of histones H3 and H4. In addition, it promoted G₀/G₁ arrest by decreasing cyclin D1 and c-myc expression, and increasing phosphorylated-cellular tumor antigen p53 and cyclin-dependent kinase inhibitor 1 (p21) expression in a dose-dependent manner. Treatment with chidamide induced cell apoptosis by upregulating the apoptosis regulator Bax/B-cell lymphoma 2 ratio in a caspase-dependent manner. In addition, the combination of chidamide with bortezomib, a proteasome inhibitor widely used as a therapeutic agent for multiple myeloma, resulted in enhanced inhibition of cell viability. In conclusion, chidamide induces a marked antimyeloma effect by inducing G₀/G₁ arrest and apoptosis via a caspase-dependent pathway. The present study provides evidence for the clinical application of chidamide in multiple myeloma.

Expression of TMEFF2 in Human Pancreatic Cancer Tissue and the Effects of TMEFF2 Knockdown on Cell, Proliferation, and Apoptosis in Human Pancreatic Cell Lines

Background

The TMEFF2 gene encodes the transmembrane protein with EGF like and two follistatin-like domains 2 and has been reported to be a tumor suppressor gene, but its role remains unknown in pancreatic cancer. This study aimed to investigate the expression of TMEFF2 in human pancreatic cancer tissue and the effects of knockdown of TMEFF2 on cell, proliferation, and apoptosis in human pancreatic cell lines.

Material/Methods

Thirty-five samples of human pancreatic tissue and adjacent normal pancreatic tissue, and five human pancreatic cancer cell lines, CAPAN1, ASPC1, BXPC3, SW1990, and CFPAC were studied. RNA expression, protein expression, cell proliferation, and apoptosis were studied using real-time polymerase chain reaction (RT-PCR), Western blot, the cell counting kit-8 (CCK-8) assay, and flow cytometry, respectively. A co-immunoprecipitation assay evaluated protein interactions.

Results

TMEFF2 expression was down-regulated in pancreatic cancer tissue compared with normal pancreas. In human pancreatic cancer cell lines, overexpression of TMEFF2 suppressed cell proliferation and enhanced apoptosis, suppressed the expression of p-STAT3, MCL1, VEGF and increased the expression of the tyrosine-specific protein phosphatase, SHP-1. The co-immunoprecipitation assay showed that TMEFF2 interacted with SHP-1. Knockdown of expression of TMEFF2 resulted in the increased expression of p-STAT3, MCL1, and VEGF, increased cell proliferation and decreased cell apoptosis, which were reversed by overexpression of SHP-1.

Conclusions

In pancreatic cancer, TMEFF2 exerted as a tumor suppressor effect by regulating p-STAT3, MCL1, and VEGF via SHP-1.

Chidamide-induced ROS accumulation and miR-129-3p-dependent cell cycle arrest in non-small lung cancer cells

BACKGROUND

Epigenetic therapy is a promising popular treatment modality for various cancers. Histone modification and miRNA should not be underestimated in lung cancer. This study aimed to investigate whether chidamide, a histone deacetylase inhibitor (HDACi), which inhibits telomerase activity and induces cell cycle arrest, influences ROS and miRNA production in non-small cell lung cancer (NSCLC) cells.

METHODS

H1355 and A549 were treated with chidamide. The analysis of DNA content was measured by FACSCalibur equipped with a 488 nm laser. H1355 cells were transfected with miR-129-3p mimic by Lipofectamine2000. Telomerase activity was performed on the telomeric repeat amplification protocol (TRAP) assay. Detection of thymidylate synthase (TS), p21, p53, pRB, and β-actin, were performed by western blot analysis.

RESULTS

Our data showed that expression of TS, p21, and pRB were altered in the presence of chidamide by PCR and western blot. Using BrdU-incorporation analysis, we found that chidamide induced G1 arrest through the regulation of the TS gene by miR-129-3p. Chidamide was shown to suppress telomerase activity in the TRAP assay and reduced the expression of human telomerase reverse transcriptase (hTERT) by PCR and q-PCR in H1355 and A549 cells. Chidamide increased the generation of reactive oxygen species (ROS) by flow cytometry. N-acetyl cysteine (NAC), a ROS scavenger, attenuated chidamide-induced telomerase activity inhibition.

CONCLUSION

Chidamide repressed telomerase activity through ROS accumulation and cell cycle arrest by miR-129-3p upregulation in both H1355 and A549 cells. This is the first study to demonstrate that chidamide induces miR-129-3p upregulation and ROS accumulation, leading to cell cycle arrest.

Aspirin Inhibits Natural Killer/T-Cell Lymphoma by Modulation of VEGF Expression and Mitochondrial Function

Extranodal nasal-type natural killer/T-cell lymphoma (NKTCL) is an Epstein-Barr virus (EBV)-associated lymphoma with a strong tendency relapse or be refractory in response to chemotherapy. Development of a new strategy for NKTCL treatment is still quite necessary. In this study, we found that aspirin treatment suppresses VEGF expression in NKTCL SNK-6 cells. Further investigation showed that aspirin treatment increases histone methylation in the range of −100~0 that is proximal to the transcription start site on the VEGF promoter, subsequently decreasing the binding ability of Sp1 to the VEGF promoter with VEGF suppression. Furthermore, aspirin treatment modulates mitochondrial function with increased ROS formation and apoptosis in NKTCL cells. Aspirin treatment alone slightly inhibits NKTCL SNK-6 tumor growth and EBV replication; while in the presence of histone deacetylase inhibitor (HDACi) chidamide (CDM), aspirin significantly suppresses the VEGF signaling pathway with increased ROS overgeneration and EBV inhibition. We also showed that with the addition of chidamide, aspirin significantly suppresses NKTCL tumor growth in both in vitro cell culture and in vivo mouse model with prolonged mouse survival. This is the first time that the potential mechanism for aspirin-mediated VEGF suppression and anti-tumor effect has been discovered, and this study provides a new strategy for anti-tumor drug development for NKTCL treatment based on aspirin-mediated targeting of the VEGF signaling pathway and ROS formation.

Histone Deacetylases (HDACs) Guided Novel Therapies for T-cell lymphomas

T-cell lymphomas are a heterogeneous group of cancers with different pathogenesis and poor prognosis. Histone deacetylases (HDACs) are epigenetic modifiers that modulate many key biological processes. In recent years, HDACs have been fully investigated for their roles and potential as drug targets in T-cell lymphomas. In this review, we have deciphered the modes of action of HDACs, HDAC inhibitors as single agents, and HDACs guided combination therapies in T-cell lymphomas. The overview of HDACs on the stage of T-cell lymphomas, and HDACs guided therapies both as single agents and combination regimens endow great opportunities for the cure of T-cell lymphomas.

The short-term effect of histone deacetylase inhibitors, chidamide and valproic acid, on the NF‑κB pathway in multiple myeloma cells

Research regarding histone deacetylase (HDAC) inhibitors (HDACis) has garnered interest for the treatment of multiple myeloma (MM). In addition, the high expression of nuclear factor (NF)-κB in MM cells is considered an important factor in the occurrence and development of MM. The present study aimed to determine the short-term effects of HDACis, chidamide and valproic acid (VPA), on MM cells, their effects on NF-κB and the underlying mechanisms. The present study measured HDAC activity, and the proliferation and apoptosis of U266 and RPMI8226 MM cells following treatment with various concentrations of chidamide and VPA for 6 and 48 h. Western blotting was used to detect the expression levels of phosphorylated (p)-IκB kinase (IKK)α/β, NF-κB p65 and inhibitor of NF-κB (IκBα) in U266 and RPMI8226 cells at various time points following treatment with chidamide and VPA (0, 2, 4 and 6 h). The results revealed that chidamide and VPA had no significant effect on the HDAC activity, proliferation and apoptosis of cells at 6 h; however, cell HDAC activity and proliferation were inhibited, and apoptosis was induced at 48 h. Furthermore, the expression levels of IκBα were gradually increased over time, whereas the expression levels of NF-κB p65 gradually decreased. These findings indicated that long-term (48 h) treatment with the HDACis chidamide and VPA inhibited the proliferation and promoted the apoptosis of MM cells; however, these HDACis had little effect on cell proliferation and apoptosis in the short term (6 h). Notably, in the short term (2-6 h), hyperactivation of NF-κB was inhibited via the IκBα-NF-κB p65 pathway. These findings indicated that cell growth may be inhibited and drug susceptibility may be promoted by blocking the NF-κB pathway at an early stage, when HDACis are combined with other drugs in the treatment of MM.

Therapeutic effects of the novel subtype-selective histone deacetylase inhibitor chidamide on myeloma-associated bone disease

Histone deacetylases are promising therapeutic targets in hematological malignancies. In the work herein, we investigated the effect of chidamide, a new subtype-selective histone deacetylase inhibitor that was independently produced in China, on multiple myeloma and its associated bone diseases using different models. The cytotoxicity of chidamide toward myeloma is due to its induction of cell apoptosis and cell cycle arrest by increasing the levels of caspase family proteins p21 and p27, among others. Furthermore, chidamide exhibited significant cytotoxicity against myeloma cells co-cultured with bone mesenchymal stromal cells and chidamide-pretreated osteoclasts. Importantly, chidamide suppressed osteoclast differentiation and resorption in vitro by dephosphorylating p-ERK, p-p38, p-AKT and p-JNK and inhibiting the expression of Cathepsin K, NFATc1 and c-fos. Finally, chidamide not only prevented tumor-associated bone loss in a disseminated murine model by partially decreasing the tumor burden but also prevented rapid receptor activator of nuclear factor κ-β ligand (RANKL)-induced bone loss in a non-tumor-bearing mouse model. Based on our results, chidamide exerted dual anti-myeloma and bone-protective effects in vitro and in vivo. These findings strongly support the potential clinical use of this drug as a treatment for multiple myeloma in the near future.

Histone deacetylase inhibitor chidamide induces growth inhibition and apoptosis in NK/T lymphoma cells through ATM-Chk2-p53-p21 signalling pathway

We investigated the anti-tumour effects and the underlying molecular mechanisms of a new oral histone deacetylase inhibitor (HDACi), chidamide, in NK/T cell lymphoma (NKTCL), a rare and highly aggressive non-Hodgkin lymphoma with poor outcomes. SNT-8 and SNK-10 NKTCL cell lines were exposed to different concentrations of chidamide for the indicated time. The treated cells were analysed for cell proliferation, cell cycle progression, and cell apoptosis. Proteins in the AKT/mTOR and MAPK signalling pathways and the DNA damage response (DDR) cell cycle checkpoint pathway were measured by Western blotting. Chidamide inhibited cell proliferation in a dose- and time-dependent manner, arrested cell cycle progression at the G0/G1 phase, and induced apoptosis in the NKTCL cell lines. In addition, we found that chidamide suppressed the phosphorylation levels of proteins in the AKT/mTOR and MAPK signalling pathways and activated the DDR cell cycle checkpoint pathway, that is, the ATM-Chk2-p53-p21 pathway. Expression of EBV genes was also assessed by Real-Time PCR. Chidamide induced EBV lytic-phase gene expression in EBV-positive NKTCL. Our results provide evidence that chidamide shows antitumour effects by inhibiting the AKT/mTOR and MAPK signalling pathways and activating the ATM-Chk2-p53-p21 signalling pathway in vitro.

Inhibitory effect of chidamide on the growth of human adenoid cystic carcinoma cells

Adenoid cystic carcinoma (ACC) is a malignant epithelial neoplasm that limitedly responses to chemotherapy at the cost of significant toxicity. There is no single targeted drug approved by Food and Drug Administration (FDA) for ACC. Genomic landscape studies have revealed that frequently mutated pathways in ACC often involve in chromatin remodeling, which interfere multiple histone related proteins. Chidamide is a novel histone deacetylase inhibitor (HDACi) approved in clinical practice that was designed to increase the acetylation level of histone H3. It demonstrated anticancer effects in various cancers in preclinical study, but not in ACC. In this study, we aimed to investigate the anticancer effects of chidamide alone or in combination with cisplatin (cDDP) on ACC in vitro and in vivo. The results showed that chidamide alone or in combination with cDDP effectively inhibited the growth and proliferation of ACC cells in a dose- and time-dependent manner. Chidamide arrested cell cycle in G2/M phase by up-regulating the acetylation of histone H3 and interfering phosphorylation of AKT protein. Chidamide alone or in combination with cDDP did not induce distinct apoptosis in ACC cells. In vivo experiments showed that chidamide combining cDDP exerted significant inhibitory effects on ACC. These suggest that chidamide may be a promising candidate drug for the treatment of patients with ACC.

HTP Nutraceutical Screening for Histone Deacetylase Inhibitors and Effects of HDACis on Tumor-suppressing miRNAs by Trichostatin A and Grapeseed (Vitis vinifera) in HeLa cells

BACKGROUND/AIM

Aggressive tumor malignancies are a consequence of delayed diagnosis, epigenetic/phenotype changes and chemo-radiation resistance. Histone deacetylases (HDACs) are a major epigenetic regulator of transcriptional repression, which are highly overexpressed in advanced malignancy. While original chemotherapy drugs were modeled after phytochemicals elucidated by botanical screenings, HDAC inhibitors (HDACi) such as apicidin, trichostatin A (TSA) and butyrate were discovered as products of fungus and microbes, in particular, gut microbiota. Therefore, a persistent question remains as to the inherent existence of HDACis in raw undigested dietary plant material. In this study, we conduct a high-throughput (HTP) screening of ~1,600 non-fermented commonly used nutraceuticals (spices, herbs, teas, vegetables, fruits, seeds, rinds etc.) at (<600 μg/ml) and food-based polyphenolics (<240 μg/ml) for evidence of HDAC activity inhibition in nuclear HeLa cell lysates.

MATERIALS AND METHODS

Human HDAC kinetic validation was performed using a standard fluorometric activity assay, followed by an enzymatic-linked immuno-captured ELISA. Both methods were verified using HDACi panel drugs: TSA, apicidin, suberohydroxamic acid, M344, CL-994, valproic acid and sodium phenylbutyrate. The HTP screening was then conducted, followed by a study comparing biological effects of HDACis in HeLa cells, including analysis of whole-transcriptome non-coding RNAs using Affymetrix miRNA 4.1-panel arrays.

RESULTS

The HTP screening results confirmed 44/1600 as potential HDACis to which 31 were further eliminated as false-positives. Methodological challenges/concerns are addressed regarding plant product false-positives that arise from the signal reduction of commercial lysine development reagents. Only 13 HDACis were found having an IC₅₀ under <200 μg/ml: Grapeseed extract (Vitis vinifera), Great burnet root (Sanguisorba Officinalis), Babul (Acacia arabica), Chinese gallnut (Melaphis chinensis), Konaberry extract (Coffea arabica), Uva Ursi (Arctostaphylos uva ursi), Green tea (Camellia sinensis), Meadowsweet (Filipendula ulmaria), Sassafras (Sassafras officinale), Turkey rhubarb (Rheum palmatum), epigallocatechin gallate (EGCG), gossypol and gallic acid. Next, we investigate the biological consequence of HDACi panel drugs in HeLa cells, where the data suggest predominant effects are anti-mitotic rather than cytotoxic. Lastly, differential effects of TSA vs. GSE at sub-lethal concentrations tested on HeLa cells show 6,631 miRNAs expressed in resting cells, 35 significantly up-regulated (TSA) and 81 up-regulated (GSE), with several miRNAs overlapping in the upward direction by both GSE and TSA (e.g. hsa-miR-23b-5p, hsa-miR-27b-5p, hsa-miR-1180-3p, hsa-miR-6880-5p and hsa-mir-943). Using DIANA miRNA online tools, it was determined that GSE and TSA simultaneously cause overexpression of similar miRNAs predicted to destroy the following influential oncogenes: NFkB, NRAS, KRAS, HRAS, MYC, TGFBR1, E2F1, E2F2, BCL21, CDKN1A, CDK6, HIF1a, and VEGFA.

CONCLUSION

The data from this study show that plant- based HDACis are relatively rare, and can elicit a similar pattern to TSA in up-regulating miRNAs involved with tumor suppression of HeLa cervical carcinoma.