Anticancer activity of SAHA, a potent histone deacetylase inhibitor, in NCI-H460 human large-cell lung carcinoma cells in vitro and in vivo

Histone Deacetylase Inhibition and Autophagy Modulation Induces a Synergistic Antiproliferative Effect and Cell Death in Cholangiocarcinoma Cells

Cholangiocarcinoma, also known as biliary tract cancer, is an aggressive adenocarcinoma arising from epithelial cells lining the intra- and extrahepatic biliary system. The effects of autophagy modulators and histone deacetylase (HDAC) inhibitors in cholangiocarcinoma are not fully known. It is essential to understand the molecular mechanisms and the effects of HDAC inhibitors in the context of cholangiocarcinoma. The antiproliferative effect of different HDAC inhibitors and autophagy modulation was investigated by the MTT cell viability assay in TFK-1 and EGI-1 cholangiocarcinoma cell lines. Combination indexes were calculated using CompuSyn software. Consequently, apoptosis was detected by Annexin V/PI staining. The effect of the drugs on the cell cycle was measured by the propidium iodide staining. The HDAC inhibition was confirmed via acetylated histone protein levels by western blotting. HDAC inhibitors, MS-275 and romidepsin, showed a better synergistic effect with the nocodazole combination. The combination treatment exerted its growth inhibitory effect by cell cycle arrest and induction of apoptosis. The cell cycle analysis of the combination treatment showed that the S phase and G2/M phase were achieved. Moreover, the necrotic and apoptotic cell population increased after single HDAC inhibitors and combination treatment. The anti-cancer effect of HDAC inhibitors is revealed by acetylation levels of histones. While acetylation levels were increased in response to HDAC inhibitors and autophagy modulator combinations, the HDAC expression decreased. This study highlights the importance of the combination of HDAC inhibition and autophagy modulators and demonstrates a synergistic effect, which could be a promising therapy and novel treatment approach for cholangiocarcinoma.

Recent Advances in Anticancer Activity of Novel Plant Extracts and Compounds from Curcuma longa in Hepatocellular Carcinoma

PURPOSE

Among all forms of cancers, hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. There are several treatment options for HCC ranging from loco-regional therapy to surgical treatment. Yet, there is high morbidity and mortality. Recent research focus has shifted towards more effective and less toxic cancer treatment options. Curcumin, the active ingredient in the Curcuma longa plant, has gained widespread attention in recent years because of its multifunctional properties as an antioxidant, anti-inflammatory, antimicrobial, and anticancer agent.

METHODS

A systematic search of PubMed, Embase and Google Scholar was performed for studies reporting incidence of HCC, risk factors associated with cirrhosis and experimental use of curcumin as an anti-cancer agent.

RESULTS

This review exclusively encompasses the anti-cancer properties of curcumin in HCC globally and it's postulated molecular targets of curcumin when used against liver cancers.

CONCLUSIONS

This review is concluded by presenting the current challenges and future perspectives of novel plant extracts derived from C. longa and the treatment options against cancers.

α-Viniferin-Induced Apoptosis through Downregulation of SIRT1 in Non-Small Cell Lung Cancer Cells

α-Viniferin, a natural stilbene compound found in plants and a polymer of resveratrol, had demonstrated potential anti-cancer and anti-inflammatory effects. However, the specific mechanisms underlying its anti-cancer activity were not yet fully understood and required further investigation. This study evaluated the effectiveness of α-viniferin and ε-viniferin using MTT assay. Results showed that α-viniferin was more effective than ε-viniferin in reducing the viability of NCI-H460 cells, a type of non-small cell lung cancer. Annexin V/7AAD assay results provided further evidence that the decrease in cell viability observed in response to α-viniferin treatment was due to the induction of apoptosis in NCI-H460 cells. The present findings indicated that treatment with α-viniferin could stimulate apoptosis in cells by cleaving caspase 3 and PARP. Moreover, the treatment reduced the expression of SIRT1, vimentin, and phosphorylated AKT, and also induced AIF nuclear translocation. Furthermore, this research provided additional evidence for the effectiveness of α-viniferin as an anti-tumor agent in nude mice with NCI-H460 cell xenografts. As demonstrated by the TUNEL assay results, α-viniferin promoted apoptosis in NCI-H460 cells in nude mice.

Histone deacetylase inhibitors as sanguine epitherapeutics against the deadliest lung cancer

The back-breaking resistance mechanisms generated by lung cancer cells against epidermal growth factor receptor (EGFR), KRAS and Janus kinase 2 (JAK2) directed therapies strongly prioritizes the requirement of novel therapies which are perfectly tolerated, potentially cytotoxic and can reinstate the drug-sensitivity in lung cancer cells. Enzymatic proteins modifying the post-translational modifications of nucleosome-integrated histone substrates are appearing as current targets for defeating various malignancies. Histone deacetylases (HDACs) are hyperexpressed in diverse lung cancer types. Blocking the active pocket of these acetylation erasers through HDAC inhibitors (HDACi) has come out as an optimistic therapeutic recourse for annihilating lung cancer. This article in the beginning gives an overview about lung cancer statistics and predominant lung cancer types. Succeeding this, compendium about conventional therapies and their serious drawbacks has been provided. Then, connection of uncommon expression of classical HDACs in lung cancer onset and expansion has been detailed. Moreover, keeping the main theme in view this article deeply discusses HDACi in the context of aggressive lung cancer as single agents and spotlights various molecular targets suppressed or induced by these inhibitors for engendering cytotoxic effect. Most particularly, the raised pharmacological effects achieved on using these inhibitors in concerted form with other therapeutic molecules and the cancer-linked pathways altered by this procedure are described. The positive direction towards further heightening of efficacy and the pressing requirement of exhaustive clinical assessment has been proposed as a new focus point.

Vorinostat enhances the therapeutic potential of Erlotinib via MAPK in lung cancer cells

BACKGROUND

Lung cancer is the second most common cancer in both men and women, with an estimated 235,760 new cases and 131,880 deaths in 2021 in the US. Despite the modern therapies being available such as radiotherapy and chemotherapy, death rates are still increasing. Erlotinib (ERL) is one of the treatment options for lung cancer, although the probability for the patients to develop resistance to ERL constrains its reliability. The aim of the present study is to assess the synergetic effect of combining ERL with vorinostat (SAHA) on the progression of lung cancer cells.

RESULTS

Adenocarcinoma alveolar basal epithelial cells (A549) were treated with either ERL, SAHA as mono drugs or with the combination of them for 24 h. Cytotoxicity assay and cell cycle analysis along with apoptosis detection were investigated. The expression profile of CDH1, TGF1, and MAPK was also assessed. Results showed an elevation in the apoptosis level in all treatments compared to WISH; the normal human amnion-derived cells. Furthermore, the treatments caused the cell cycle to arrest at G2/M, indicating its cytotoxic activity.

CONCLUSION

The combination of SAHA and ERL significantly increased the level of apoptosis in lung cancer cells. Meanwhile, this combination treatment downregulated MAPK compared to the mono drugs and the control cells, suggesting the potential role of MAPK in regulating apoptosis and cell cycle machinery in lung cancer.

The Effect of Organoselenium Compounds on Histone Deacetylase Inhibition and Their Potential for Cancer Therapy

Genetic and epigenetic changes alter gene expression, contributing to cancer. Epigenetic changes in cancer arise from alterations in DNA and histone modifications that lead to tumour suppressor gene silencing and the activation of oncogenes. The acetylation status of histones and non-histone proteins are determined by the histone deacetylases and histone acetyltransferases that control gene transcription. Organoselenium compounds have become promising contenders in cancer therapeutics. Apart from their anti-oxidative effects, several natural and synthetic organoselenium compounds and metabolites act as histone deacetylase inhibitors, which influence the acetylation status of histones and non-histone proteins, altering gene transcription. This review aims to summarise the effect of natural and synthetic organoselenium compounds on histone and non-histone protein acetylation/deacetylation in cancer therapy.

Cardiomyogenic Differentiation Potential of Human Dilated Myocardium-Derived Mesenchymal Stem/Stromal Cells: The Impact of HDAC Inhibitor SAHA and Biomimetic Matrices

Dilated cardiomyopathy (DCM) is the most common type of nonischemic cardiomyopathy characterized by left ventricular or biventricular dilation and impaired contraction leading to heart failure and even patients’ death. Therefore, it is important to search for new cardiac tissue regenerating tools. Human mesenchymal stem/stromal cells (hmMSCs) were isolated from post-surgery healthy and DCM myocardial biopsies and their differentiation to the cardiomyogenic direction has been investigated in vitro. Dilated hmMSCs were slightly bigger in size, grew slower, but had almost the same levels of MSC-typical surface markers as healthy hmMSCs. Histone deacetylase (HDAC) activity in dilated hmMSCs was 1.5-fold higher than in healthy ones, which was suppressed by class I and II HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) showing activation of cardiomyogenic differentiation-related genes alpha-cardiac actin (ACTC1) and cardiac troponin T (TNNT2). Both types of hmMSCs cultivated on collagen I hydrogels with hyaluronic acid (HA) or 2-methacryloyloxyethyl phosphorylcholine (MPC) and exposed to SAHA significantly downregulated focal adhesion kinase (PTK2) and activated ACTC1 and TNNT2. Longitudinal cultivation of dilated hmMSC also upregulated alpha-cardiac actin. Thus, HDAC inhibitor SAHA, in combination with collagen I-based hydrogels, can tilt the dilated myocardium hmMSC toward cardiomyogenic direction in vitro with further possible therapeutic application in vivo.

Understanding Failure and Improving Treatment Using HDAC Inhibitors for Prostate Cancer

Novel treatment regimens are required for castration-resistant prostate cancers (CRPCs) that become unresponsive to standard treatments, such as docetaxel and enzalutamide. Histone deacetylase (HDAC) inhibitors showed promising results in hematological malignancies, but they failed in solid tumors such as prostate cancer, despite the overexpression of HDACs in CRPC. Four HDAC inhibitors, vorinostat, pracinostat, panobinostat and romidepsin, underwent phase II clinical trials for prostate cancers; however, phase III trials were not recommended due to a majority of patients exhibiting either toxicity or disease progression. In this review, the pharmacodynamic reasons for the failure of HDAC inhibitors were assessed and placed in the context of the advancements in the understanding of CRPCs, HDACs and resistance mechanisms. The review focuses on three themes: evolution of androgen receptor-negative prostate cancers, development of resistance mechanisms and differential effects of HDACs. In conclusion, advancements can be made in this field by characterizing HDACs in prostate tumors more extensively, as this will allow more specific drugs catering to the specific HDAC subtypes to be designed.

Strong Antitumor Activity of Bevacizumab and Aflibercept in Neuroendocrine Carcinomas: In-Depth Preclinical Study

BACKGROUND

Neuroendocrine carcinoma (NEC) is a rare and very aggressive tumor. It has been greatly understudied, and very little is known about optimal treatment strategy for patients with this disease. The purpose of this study was to evaluate in vivo whether anti-vascular endothelial growth factor (VEGF) drugs could be a therapeutic alternative for these tumors with a poor prognosis.

METHODS

We have developed 2 xenograft models using either human cell line derived from lung (H460) or from colon (COLO320) NEC to assess the effect of 2 antiangiogenic drugs, aflibercept and bevacizumab, on tumor growth and their pathological characteristics. Additionally, tumors were subjected to immunohistochemistry staining and proteins were measured with Western blot and ELISA.

RESULTS

Both aflibercept and bevacizumab showed significant antitumor activity (p < 0.001). In the H460 model, aflibercept resulted in 94% tumor growth inhibition (TGI) and bevacizumab treatment resulted in 72.2% TGI. Similarly, in the COLO320 model, aflibercept and bevacizumab resulted in 89.3 and 84% TGI, respectively. Moreover, antitumor activity occurs early after treatment initiation. Using Tumor Control Index score, which address the kinetics of tumor growth in a way comparable to the methods used in human clinical studies, we confirmed that both drugs inhibit significantly tumor growth. When tumor stabilization was evaluated, aflibercept shows higher ability to stabilize NEC tumors than bevacizumab.

CONCLUSION

Results derived from this study strongly support anti-VEGF therapies, especially aflibercept, as a novel therapeutic option in NECs. Further studies are necessary, but our observations encourage the evaluation of antiangiogenics in clinical trials combined with standard chemotherapy.

Overexpression of miR-4433 by suberoylanilide hydroxamic acid suppresses growth of CML cells and induces apoptosis through targeting Bcr-Abl

Background: Targeting Bcr-Abl is the key for the treatment of CML. Although great progress has been achieved for the treatment of CML patients in chronic stage, effective drugs with good safety are not available for those in advanced stages of CML patients. In present study, a histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), was used to screen for microRNA that can target Bcr-Abl.

Methods: RT-qPCR was used to determine Bcr-Abl and miR-4433 transcription level in CML cells. In CML cells, Proteins including PARP, caspase-3, acetyl-histone 3, histone 3 and Bcr-Abl, as well as Bcr-Abl downstream proteins were detected using western blot. Cell viability and apoptosis were monitored respectively by MTS assay and flow cytometry. The correlation between miR-4433 and Bcr-Abl was determined by luciferase reporter assay. The anti-tumor effect of miR-4433 to K562 cells was evaluated by nude mouse xenograft model in vivo.

Results: SAHA up-regulated the acetylation level of histone 3, and effectively inhibited Bcr-Abl mRNA level and its downstream signal transduction pathway, while inhibiting the growth of CML cells and inducing apoptosis. Furthermore, bioinformatics tools predicted that miR-4433 is a putative microRNA targeting Bcr-Abl and that the expression level of miR-4433 was significantly increased after SAHA treatment in K562 cells. Luciferase activity analysis revealed that miR-4433 directly targets Bcr-Abl. Additionally, transient expression of miR-4433 abrogated Bcr-Abl activity and its downstream signaling pathways while inducing apoptosis in K562 cells. Moreover, stable expression of miR-4433 suppressed Bcr-Abl and its downstream signaling pathway, and inhibited the growth of K562 cells in vitro and the growth of K562-xenografts in nude mice.

Conclusion: miR-4433 was identified as a microRNA targeting Bcr-Abl, which may be subject to epigenetic regulation of SAHA, a histone deacetylase inhibitor that has been approved by the US FDA for the treatment of cutaneous T-cell lymphoma. The findings of this study provide a molecular basis from another angle for the use of SAHA in the treatment of CML.

Antioxidant and anticancer activity of synthesized 4-amino-5-((aryl substituted)-4H-1,2,4-triazole-3-yl)thio-linked hydroxamic acid derivatives

OBJECTIVES

The antioxidant and anticancer activity of twelve 5-substituted-4-amino-1,2,4-triazole-linked hydroxamic acid derivatives were evaluated.

METHODS

Previously synthesized 2-((4-amino-5-substituted-4H-1,2,4-triazol-3-yl)thio)-N-hydroxyacetamide and 3-((4-amino-5-substituted-4H-1,2,4-triazol-3-yl)thio)-N-hydroxypropanamide (6a-6l) were evaluated for in vitro antioxidant and in vivo anticancer activity. MDA-MB-231, MCF-7 and HCT 116 cell lines were used to evaluate IC₅₀ values, in vitro. Ehrlich ascites carcinoma (EAC)-induced mice model was used to evaluate in vivo anticancer potential. Different biological markers were examined for drug-related toxicities.

KEY FINDINGS

Compound 6b revealed more potent antioxidant property among all tested compounds, even than the ascorbic acid. The IC₅₀ values of compound 6b were found to be 5.71 ± 2.29 μg/ml (DPPH assay) and 4.12 ± 0.5 μg/ml (ABTS assay). Histopathology of liver sections of drug-treated mice was evaluated. Survival analysis showed that compound 6b could increase the life span as of the standard drug.

CONCLUSIONS

After the assessment of all in vivo anticancer study related data, it was found that compound 6b possess superior anticancer potency in terms of efficacy and toxicity. From this experimental design, it could be concluded that further modification of this prototypical structure will lead to develop more potent antioxidant as well as an anticancer agent in the future.

Antitumor effects of histone deacetylase inhibitor suberoylanilide hydroxamic acid in epidermal growth factor receptor-mutant non-small-cell lung cancer lines in vitro and in vivo

Histone acetylation is one of the most abundant post-translational modifications in eukaryotic cells; aberrant histone acetylation is related to a range of cancer types because of the dysregulation of histone deacetylases (HDACs). Inhibition of HDACs leads to suppression of tumor growth in multiple cancers, whereas the inhibitory effects of HDAC inhibitors remain incompletely understood in epidermal growth factor receptor (EGFR)-mutant lung cancers. In this study, the antitumor effects of HDACs inhibitor suberoylanilide hydroxamic acid (SAHA, vorinostat) were examined in EGFR-mutant lung cancer cell lines. The results of the present work showed that SAHA markedly inhibited cell viability and proliferation, induced cell apoptosis by arresting the cell cycle in the G2/M phase, and significantly reduced tumor growth in a xenograft model. Further study confirmed that the suppression function of SAHA might be mediated by regulating the ERK-dependent and/or the AKT-dependent pathway; meanwhile, angiogenesis abrogation induced by SAHA exerted effects on tumor regression in vivo. Taken together, our results identify the antitumor effects of HDACs inhibitor SAHA as an alternative therapeutic application for the epigenetic treatment of EGFR-mutant non-small-cell lung cancer.

Structural optimization and evaluation of novel 2-pyrrolidone-fused (2-oxoindolin-3-ylidene)methylpyrrole derivatives as potential VEGFR-2/PDGFRβ inhibitors

Background

Tumor angiogenesis, essential for tumor growth and metastasis, is tightly regulated by VEGF/VEGFR and PDGF/PDGFR pathways, and therefore blocking those pathways is a promising therapeutic target. Compared to sunitinib, the C(5)-Br derivative of 2-pyrrolidone-fused (2-oxoindolin-3-ylidene)methylpyrrole has significantly greater in vitro activities against VEGFR-2, PDGFRβ, and tube formation.

Results and discussion

The objective of this study was to perform further structural optimization, which revealed certain new products with even more potent anti-tumor activities, both cellularly and enzymatically. Of these, 15 revealed ten- and eightfold stronger potencies against VEGFR-2 and PDGFRβ than sunitinib, respectively, and showed selectivity against HCT116 with a favorable selective index (SI > 4.27). The molecular docking results displayed that the ligand–protein binding affinity to VEGFR-2 could be enhanced by introducing a hydrogen-bond-donating (HBD) substituent at C(5) of (2-oxoindolin-3-ylidene)methylpyrrole such as 14 (C(5)-OH) and 15 (C(5)-SH).

Conclusions

Among newly synthetic compounds, 7 and 13–15 exhibited significant inhibitory activities against VEGFR-2 and PDGFRβ. Of these, the experimental results suggest that 15 might be a promising anti-proliferative agent. Graphical abstract

Synthesis and Evaluation of Novel 2-Pyrrolidone-Fused (2-Oxoindolin-3-ylidene)methylpyrrole Derivatives as Potential Multi-Target Tyrosine Kinase Receptor Inhibitors

Signaling pathways of VEGFs and PDGFs are crucial in tumor angiogenesis, which is essential in solid tumor progression and metastasis. This study reports our strategy for designing and synthesizing a series of novel 2-pyrrolidone-fused (2-oxoindolin-3-ylidene)methylpyrrole derivatives as potential multi-target tyrosine kinase receptor inhibitors. The target compounds were obtained by condensation of 5-substituted oxindoles with N-substituted 2-pyrrolidone aldehyde 7 in satisfactory yields. Of these, 11 and 12 had the highest potency and, compared to sunitinib, showed: (1) significant increase in anti-proliferation of various cancer cells with a favorable selective index (SI); (2) higher inhibitory potency against both VEGFR-2 and PDGFRβ. The molecular modeling results showed that, in terms of VEGFR-2 binding, the synthesized products had a similar binding mode to sunitinib but with tighter interaction.

Design and Synthesis of C3-Substituted β-Carboline-Based Histone Deacetylase Inhibitors with Potent Antitumor Activities

A series of hydroxamic acid histone deacetylase (HDAC) inhibitors in which the β-carboline motif has been incorporated were designed and synthesized. The effect of substitution at the C3 amide on HDAC inhibition and antiproliferative activities was investigated. Most of these compounds were found to display significant HDAC inhibitory effects and good antiproliferative activity, with IC₅₀ values in the low-micromolar range. In particular, the HDAC inhibition IC₅₀ value of N-(2-(dimethylamino)ethyl)-N-(4-(hydroxylcarbamoyl)benzyl)-1-(4-methoxyphenyl)-9H-pyrido[3,4-b]indole-3-carboxamide (9 h) is five-fold lower than that of suberoylanilide hydroxamic acid (SAHA, vorinostat). Furthermore, 9 h was found to increase the acetylation of histone H3 and α-tubulin, and to induce DNA damage as evidenced by hypochromism and enhanced phosphorylation of histone H2AX. Compound 9 h inhibits Stat3, Akt, and ERK signaling, important cell-growth-promoting pathways that are aberrantly activated in most cancers. Finally, 9 h showed reasonable solubility and permeability in Caco-2 cells. Our findings suggest that these novel β-carboline-based HDAC inhibitors may hold great promise as therapeutic agents for the treatment of human cancers.

Synergistic Immunostimulatory Effects and Therapeutic Benefit of Combined Histone Deacetylase and Bromodomain Inhibition in Non-Small Cell Lung Cancer

Effective therapies for non-small cell lung cancer (NSCLC) remain challenging despite an increasingly comprehensive understanding of somatically altered oncogenic pathways. It is now clear that therapeutic agents with potential to impact the tumor immune microenvironment potentiate immune-orchestrated therapeutic benefit. Herein, we evaluated the immunoregulatory properties of histone deacetylase (HDAC) and bromodomain inhibitors, two classes of drugs that modulate the epigenome, with a focus on key cell subsets that are engaged in an immune response. By evaluating human peripheral blood and NSCLC tumors, we show that the selective HDAC6 inhibitor ricolinostat promotes phenotypic changes that support enhanced T-cell activation and improved function of antigen-presenting cells. The bromodomain inhibitor JQ1 attenuated CD4⁺FOXP3⁺ T regulatory cell suppressive function and synergized with ricolinostat to facilitate immune-mediated tumor growth arrest, leading to prolonged survival of mice with lung adenocarcinomas. Collectively, our findings highlight the immunomodulatory effects of two epigenetic modifiers that, together, promote T cell-mediated antitumor immunity and demonstrate their therapeutic potential for treatment of NSCLC.Significance: Selective inhibition of HDACs and bromodomain proteins modulates tumor-associated immune cells in a manner that favors improved T-cell function and reduced inhibitory cellular mechanisms. These effects facilitated robust antitumor responses in tumor-bearing mice, demonstrating the therapeutic potential of combining these epigenetic modulators for the treatment of NSCLC. Cancer Discov; 7(8); 852-67. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 783.

The histone deacetylase inhibitor trichostatin a decreases lymphangiogenesis by inducing apoptosis and cell cycle arrest via p21-dependent pathways

Background

The formation of new lymphatic vessels provides an additional route for tumour cells to metastasize. Therefore, inhibiting lymphangiogenesis represents an interesting target in cancer therapy. First evidence suggests that histone deacetylase inhibitors (HDACi) may mediate part of their antitumor effects by interfering with lymphangiogenesis. However, the underlying mechanisms of HDACi induced anti-lymphangiogenic properties are not fully investigated so far and in part remain unknown.

Methods

Human lymphatic endothelial cells (LEC) were cultured in vitro and treated with or without HDACi. Effects of HDACi on proliferation and cell cycle progress were analysed by BrdU assay and flow cytometry. Apoptosis was measured by quantifying mono- and oligonucleosomes in the cytoplasmic fraction of cell lysates. In vitro lymphangiogenesis was investigated using the Matrigel short term lymphangiogenesis assay. The effects of TSA on cell cycle regulatory proteins and apoptosis-related proteins were examined by western blotting, immunofluorescence staining and semi-quantitative RT-PCR. Protein- and mRNA half-life of p21 were analysed by western blotting and quantitative RT-PCR. The activity of the p21 promoter was determined using a dual luciferase assay and DNA-binding activity of Sp1/3 was investigated using EMSA. Furthermore, siRNA assays were performed to analyse the role of p21 and p53 on TSA-mediated anti-lymphangiogenic effects.

Results

We found that HDACi inhibited cell proliferation and that the pan-HDACi TSA induced G0/G1 arrest in LEC. Cell cycle arrest was accompanied by up-regulation of p21, p27 and p53. Additionally, we observed that p21 protein accumulated in cellular nuclei after treatment with TSA. Moreover, we found that p21 mRNA was significantly up-regulated by TSA, while the protein and mRNA half-life remained largely unaffected. The promoter activity of p21 was enhanced by TSA indicating a transcriptional mechanism. Subsequent EMSA analyses showed increased constitutive Sp1/3-dependent DNA binding in response to HDACi. We demonstrated that p53 was not required for TSA induced p21 expression and growth inhibition of LECs. Interestingly, siRNA-mediated p21 depletion almost completely reversed the anti-proliferative effects of TSA in LEC. In addition, TSA induced apoptosis by cytochrome c release contributed to activating caspases-9, −7 and −3 and downregulating the anti-apoptotic proteins cIAP-1 and −2.

Conclusions

In conclusion, we demonstrate that TSA - a pan-HDACi - has distinct anti-lymphangiogenic effects in primary human lymphatic endothelial cells by activating intrinsic apoptotic pathway and cell cycle arrest via p21-dependent pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2807-y) contains supplementary material, which is available to authorized users.

The Histone Deacetylase Inhibitor JAHA Down-Regulates pERK and Global DNA Methylation in MDA-MB231 Breast Cancer Cells

The histone deacetylase inhibitor N¹-(ferrocenyl)-N⁸-hydroxyoctanediamide (JAHA) down-regulates extracellular-signal-regulated kinase (ERK) and its activated form in triple-negative MDA-MB231 breast cancer cells after 18 h and up to 30 h of treatment, and to a lesser extent AKT and phospho-AKT after 30 h and up to 48 h of treatment. Also, DNA methyltransferase 1 (DNMT1), 3b and, to a lesser extent, 3a, downstream ERK targets, were down-regulated already at 18 h with an increase up to 48 h of exposure. Methylation-sensitive restriction arbitrarily-primed (MeSAP) polymerase chain reaction (PCR) analysis confirmed the ability of JAHA to induce genome-wide DNA hypomethylation at 48 h of exposure. Collective data suggest that JAHA, by down-regulating phospho-ERK, impairs DNMT1 and 3b expression and ultimately DNA methylation extent, which may be related to its cytotoxic effect on this cancer cytotype.

Molecular Mechanism of the Cell Death Induced by the Histone Deacetylase Pan Inhibitor LBH589 (Panobinostat) in Wilms Tumor Cells

Background

Wilms tumor (WT) is an embryonic kidney cancer, for which histone acetylation might be a therapeutic target. LBH589, a novel targeted agent, suppresses histone deacetylases in many tumors. This study investigated the antitumor activity of LBH589 in SK-NEP-1 and G401 cells.

Methods

SK-NEP-1 and G401 cell growth was assessed by CCK-8 and in nude mice experiments. Annexin V/propidium iodide staining followed by flow cytometry detected apoptosis in cell culture. Gene expressions of LBH589-treated tumor cells were analyzed using an Arraystar Human LncRNA Array. The Multi Experiment View cluster software analyzed the expression data. Differentially expressed genes from the cluster analyses were imported into the Ingenuity Pathway Analysis tool.

Results

LBH589 inhibited cell proliferation of SK-NEP-1 and G401 cells in a dose-dependent manner. Annexin V, TUNEL and Hochest 33342 staining analysis showed that LBH589-treated cells showed more apoptotic features compared with the control. LBH589 treatment inhibited the growth of SK-NEP-1 xenograft tumors in nude mice. Arraystar Human LncRNA Array analysis of genes and lncRNAs regulated by LBH589 identified 6653 mRNAs and 8135 lncRNAs in LBH589-treated SK-NEP-1 cells. The most enriched gene ontology terms were those involved in nucleosome assembly. KEGG pathway analysis identified cell cycle proteins, including CCNA2, CCNB2, CCND1, CCND2, CDK4, CDKN1B and HDAC2, etc. Ingenuity Pathway Analysis identified important upstream molecules: HIST2H3C, HIST1H4A, HIST1A, HIST1C, HIST1D, histone H1, histone H3, RPRM, HSP70 and MYC.

Conclusions

LBH589 treatment caused apoptosis and inhibition of cell proliferation of SK-NEP-1and G401 cells. LBH589 had a significant effect and few side effects on SK-NEP-1 xenograft tumors. Expression profiling, and GO, KEGG and IPA analyses identified new targets and a new “network” of genes responding to LBH589 treatment in SK-NEP-1 cells. RPRM, HSP70 and MYC may be important regulators during LBH589 treatment. Our results provide new clues to the proapoptotic mechanism of LBH589.

Sodium valproate, a histone deacetylase inhibitor, modulates the vascular endothelial growth inhibitor-mediated cell death in human osteosarcoma and vascular endothelial cells

The level of vascular endothelial growth inhibitor (VEGI) has been reported to be negatively associated with neovascularization in malignant tumors. The soluble form of VEGI is a potent anti-angiogenic factor due to its effects in inhibiting endothelial cell proliferation. This inhibition is mediated by death receptor 3 (DR3), which contains a death domain in its cytoplasmic tail capable of inducing apoptosis that can be subsequently blocked by decoy receptor 3 (DcR3). We investigated the effects of sodium valproate (VPA) and trichostatin A (TSA), histone deacetylase inhibitors, on the expression of VEGI and its related receptors in human osteosarcoma (OS) cell lines and human microvascular endothelial (HMVE) cells. Consequently, treatment with VPA and TSA increased the VEGI and DR3 expression levels without inducing DcR3 production in the OS cell lines. In contrast, the effect on the HMVE cells was limited, with no evidence of growth inhibition or an increase in the DR3 and DcR3 expression. However, VPA-induced soluble VEGI in the OS cell culture medium markedly inhibited the vascular tube formation of HMVE cells, while VEGI overexpression resulted in enhanced OS cell death. Taken together, the HDAC inhibitor has anti-angiogenesis and antitumor activities that mediate soluble VEGI/DR3-induced apoptosis via both autocrine and paracrine pathways. This study indicates that the HDAC inhibitor may be exploited as a therapeutic strategy modulating the soluble VEGI/DR3 pathway in osteosarcoma patients.

CD3+ CD4+ and CD3+ CD8+ lymphocyte subgroups and their surface receptors NKG2D and NKG2A in patients with non-small cell lung cancer

BACKGROUND

To explore the prevalence of lymphocyte subgroups CD3+ CD4+ and CD3+ CD8+ and their surface receptors NKG2D and NKG2A in patients with non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

A total of 40 patients with NSCLC were divided into different groups according to different clinical factors (TNM staging, pathological patterns and genders) for assessment of relations with CD3+ CD4+ and CD3+ CD8+ and the surface receptors NKG2D and NKG2A of T lymphocytes in peripheral blood by flow cytometry.

RESULTS

Patients in the advanced group had evidently lower levels of CD3+ CD4+ but markedly higher levels of CD3+ CD8+ in peripheral blood than those with early lesions (p<0.05). In addition, NSCLC patients in the advanced group had obviously higher CD3+ CD4+ NKG2D and CD3+ CD8+ NKG2A expression rates but lower CD3+ CD4+ NKG2A and CD3+ CD8+ NKG2D expression rates (p<0.05). However, there were no significant differences between NSCLC patients with different genders and pathological patterns in expression levels of lymphocyte subgroups CD3+ CD4+ and CD3+ CD8+ and their surface receptors NKG2D and NKG2A.

CONCLUSIONS

Unbalanced expression of surface receptors NKG2D and NKG2A in CD3+ CD4+ and CD3+ CD8+ lymphocytes may be associated with a poor prognosis, greater malignancy and immunological evasion by advanced cancers, related to progression of lung cancer.