Clinicopathological features and prediction values of HDAC1, HDAC2, HDAC3, and HDAC11 in classical Hodgkin lymphoma

Advances in Hodgkin Lymphoma Treatment: From Molecular Biology to Clinical Practice

Classical Hodgkin Lymphoma (cHL) is a highly curable disease, but around 20% of patients experience progression or relapse after standard frontline chemotherapy regimens. Salvage regimens followed by autologous stem cell transplants represent the historical treatment approach for these cases. In the last decade, with the increasing understanding of cHL biology and tumor microenvironment role in disease course, novel molecules have been introduced in clinical practice, improving outcomes in the relapsed/refractory setting. The anti-CD30 antibody-drug conjugated brentuximab vedotin and PD-1/PD-L1 checkpoint inhibitors represent nowadays curative options for chemorefractory patients, and randomized trials recently demonstrated their efficacy in frontline immune-chemo-combined modalities. Several drugs able to modulate the patients' T-lymphocytes and NK cell activity are under development, as well as many anti-CD30 chimeric antigen receptor T-cell products. Multiple tumor aberrant epigenetic mechanisms are being investigated as targets for antineoplastic compounds such as histone deacetylase inhibitors and hypomethylating agents. Moreover, JAK2 inhibition combined with anti-PD1 blockade revealed a potential complementary therapeutic pathway in cHL. In this review, we will summarize recent findings on cHL biology and novel treatment options clinically available, as well as promising future perspectives in the field.

HDAC11 is related to breast cancer prognosis and inhibits invasion and proliferation of breast cancer cells

OBJECTIVE

Histone deacetylases (HDACs) not only regulate histone acetylation but also participate in many pathophysiologic processes, especially the development of cancer, including breast cancer. However, whether Histone deacetylase 11 can influence breast cancer is still unknown. This study investigated the relationship between HDAC11 expression in breast cancers and clinicopathologic parameters, and used small interference RNA (siRNA) to determine the biological behavioural changes after knockdown of HDAC11.

METHODS

Immunohistochemical (IHC) staining was employed to detect the expression of HDAC11 in a tissue microarray (TMA) of 145 patients with invasive ductal breast carcinoma. Transwell and wound healing assays were employed to analyze cell invasion and migration. The proliferation ability of cells was determined by Cell Counting Kit (CCK8).

RESULTS

The results show that the expression of HDAC11 was positively correlated with the overall survival (OS) of breast cancer patients. Specific HDAC11 knockdown enhanced MDA-MB-231 cell proliferation, migration, and invasion.

CONCLUSION

In conclusion, this study found that HDAC11 expression is positively correlated with the overall survival rate of patients. HDAC11 can inhibit the invasion and proliferation of breast cancer cells to a certain extent and can be used as a good prognosis marker.

New molecular targets in Hodgkin and Reed-Sternberg cells

Recent discoveries shed light on molecular mechanisms responsible for classical Hodgkin lymphoma (HL) development and progression, along with features of Hodgkin - Reed and Sternberg cells (HRS). Here, we summarize current knowledge on characteristic molecular alterations in HL, as well as existing targeted therapies and potential novel treatments for this disease. We discuss the importance of cluster of differentiation molecule 30 (CD30) and the programmed cell death-1 protein (PD-1) and ligands (PD-L1/2), and other molecules involved in immune modulation in HL. We highlight emerging evidence indicating that the altered function of SWI/SNF-type chromatin remodeling complexes, PRC2, and other epigenetic modifiers, contribute to variations in chromatin status, which are typical for HL. We postulate that despite of the existence of plentiful molecular data, the understanding of HL development remains incomplete. We therefore propose research directions involving analysis of reverse signaling in the PD-1/PD-L1 mechanism, chromatin remodeling, and epigenetics-related alterations, in order to identify HL features at the molecular level. Such attempts may lead to the identification of new molecular targets, and thus will likely substantially contribute to the future development of more effective targeted therapies.

Design, synthesis and antitumor activity study of PARP-1/HDAC dual targeting inhibitors

Both poly(ADP-ribose)polymerase-1 (PARP-1) and histone deacetylase (HDAC) are important antitumor targets and have attracted extensive attention. In this work, a total of fourteen PARP-1/HDAC dual targeting inhibitors were designed and synthesized using either benzopyrazole or benzimidazole as core structures. Two leading compounds 1-8-6 and 1-8-7 were proven to be dual targeting inhibitors of PARP-1 and HDAC6, and showed high antiproliferative activities against six human cancer cell lines with IC₅₀ values in micromole range. Moreover, compounds 1-8-6 and 1-8-7 could impair tumor cell proliferation in 48 h and 72 h with much higher potency than co-treatment of Olaparib and Tubastatin A. 1-8-6 displayed remarkable anti-migration and anti-angiogenesis activities. Meanwhile, western blot experiment result showed that 1-8-6 was able to heighten expression level of acetylated α-tubulin with marginal effects to acetylated histones H3 and H4. Finally, docking simulation work showed that 1-8-6 could fit into the active sites of PARP-1 and HDAC6. All results indicated that 1-8-6 is a promising candidate for further preclinical studies.

Targeting pancreatic cancer immune evasion by inhibiting histone deacetylases

The immune system plays a vital role in maintaining the delicate balance between immune recognition and tumor development. Regardless, it is not uncommon that cancerous cells can intelligently acquire abilities to bypass the antitumor immune responses, thus allowing continuous tumor growth and development. Immune evasion has emerged as a significant factor contributing to the progression and immune resistance of pancreatic cancer. Compared with other cancers, pancreatic cancer has a tumor microenvironment that can resist most treatment modalities, including emerging immunotherapy. Sadly, the use of immunotherapy has yet to bring significant clinical breakthrough among pancreatic cancer patients, suggesting that pancreatic cancer has successfully evaded immunomodulation. In this review, we summarize the impact of genetic alteration and epigenetic modification (especially histone deacetylases, HDAC) on immune evasion in pancreatic cancer. HDAC overexpression significantly suppresses tumor suppressor genes, contributing to tumor growth and progression. We review the evidence on HDAC inhibitors in tumor eradication, improving T cells activation, restoring tumor immunogenicity, and modulating programmed death 1 interaction. We provide our perspective in targeting HDAC as a strategy to reverse immune evasion in pancreatic cancer.

HDAC11: a multifaceted histone deacetylase with proficient fatty deacylase activity and its roles in physiological processes

The histone deacetylases (HDACs) family of enzymes possess deacylase activity for histone and nonhistone proteins; HDAC11 is the latest discovered HDAC and the only member of class IV. Besides its shared HDAC family catalytical activity, recent studies underline HDAC11 as a multifaceted enzyme with a very efficient long-chain fatty acid deacylase activity, which has open a whole new field of action for this protein. Here, we summarize the importance of HDAC11 in a vast array of cellular pathways, which has been recently highlighted by discoveries about its subcellular localization, biochemical features, and its regulation by microRNAs and long noncoding RNAs, as well as its new targets and interactors. Additionally, we discuss the recent work showing the consequences of HDAC11 dysregulation in brain, skeletal muscle, and adipose tissue, and during regeneration in response to kidney, skeletal muscle, and vascular injuries, underscoring HDAC11 as an emerging hub protein with physiological functions that are much more extensive than previously thought, and with important implications in human diseases.

HDAC11: a rising star in epigenetics

Epigenetic mechanisms, such as acetylation, methylation, and succinylation, play pivotal roles in the regulation of multiple normal biological processes, including neuron regulation, hematopoiesis, bone cell maturation, and metabolism. In addition, epigenetic mechanisms are closely associated with the pathological processes of various diseases, such as metabolic diseases, autoimmune diseases and cancers. Epigenetic changes may precede genetic mutation, so research on epigenetic changes and regulation may be important for the early detection and diagnosis of disease. Histone deacetylase11 (HDAC11) is the newest member of the histone deacetylase (HDAC) family and the only class IV histone deacetylase. HDAC11 has different expression levels and biological functions in different systems of the human body and is among the top 1 to 4% of genes overexpressed in cancers, such as breast cancer, hepatocellular carcinoma and renal pelvis urothelial carcinoma. This article analyzes the role and mechanism of HDAC11 in disease, especially in tumorigenesis, in an attempt to provide new ideas for clinical and basic research.

Histone modifications in epigenetic regulation of cancer: Perspectives and achieved progress

Epigenetic changes associated with histone modifications play an important role in the emergence and maintenance of the phenotype of various cancer types. In contrast to direct mutations in the main DNA sequence, these changes are reversible, which makes the development of inhibitors of enzymes of post-translational histone modifications one of the most promising strategies for the creation of anticancer drugs. To date, a wide variety of histone modifications have been found that play an important role in the regulation of chromatin state, gene expression, and other nuclear events. This review examines the main features of the most common and studied epigenetic histone modifications with a proven role in the pathogenesis of a wide range of malignant neoplasms: acetylation / deacetylation and methylation / demethylation of histone proteins, as well as the role of enzymes of the HAT / HDAC and HMT / HDMT families in the development of oncological pathologies. The data on the relationship between histone modifications and certain types of cancer are presented and discussed. Special attention is devoted to the consideration of various strategies for the development of epigenetic inhibitors. The main directions of the development of inhibitors of histone modifications are analyzed and effective strategies for their creation are identified and discussed. The most promising strategy is the use of multitarget drugs, which will affect multiple molecular targets of cancer. A critical analysis of the current status of approved epigenetic anticancer drugs has also been performed.

Tambulin Targets Histone Deacetylase 1 Inhibiting Cell Growth and Inducing Apoptosis in Human Lung Squamous Cell Carcinoma

There is an urgent unmet need to develop new therapeutics for lung squamous cell carcinoma (LSCC) as the current gold standard treatment regimens are dominated by chemotherapy. In this study, we observed the treatment effects of the natural compound tambulin on LSCC and explored its mechanism of action. LSCC cell lines H226 and H520 were cultured in vitro to observe the effects of tambulin on cell proliferation and apoptosis. Western blotting was used to detect the expression of histone deacetylase 1 (HDAC1) and apoptosis-related proteins. Cell derived xenografts (CDX) of H226 and H520 in nude mice were established to examine the inhibitory effects of tambulin in vivo. Results showed that tambulin inhibited the proliferation of H226 and H520 cells in a dose-dependent manner and inhibited the growth of CDX tumors. Tambulin also promoted the apoptosis of H226 and H520 cells, up-regulated the protein expression of cleaved caspase-3, cleaved caspase-9 and Bax, and down-regulated HDAC1 and Bcl-2 protein expression. In support of this, immunohistochemical analysis of CDX tumors from mice treated with tambulin showed increased expression of cleaved caspase-3 and Bax, while the expression of HDAC1 and Bcl-2 were decreased. What’s more, when HDAC1 was over-expressed via adenovirus transduction in H226 or H520 cells, the effects of tambulin were significantly attenuated. Interestingly, we found that combining tambulin with cisplatin treatment in CDX models was more effective than single drug treatment, suggesting that tambulin may enhance the sensitivity of LSCC to cisplatin. Taken together, this study proves that tambulin has a definite therapeutic effect on LSCC. Mechanistically, tambulin downregulates HDAC1, which in turn regulates the Bcl-2/caspase signaling pathway and promotes cancer cell apoptosis.

Targeting epigenetic regulators for cancer therapy: mechanisms and advances in clinical trials

Epigenetic alternations concern heritable yet reversible changes in histone or DNA modifications that regulate gene activity beyond the underlying sequence. Epigenetic dysregulation is often linked to human disease, notably cancer. With the development of various drugs targeting epigenetic regulators, epigenetic-targeted therapy has been applied in the treatment of hematological malignancies and has exhibited viable therapeutic potential for solid tumors in preclinical and clinical trials. In this review, we summarize the aberrant functions of enzymes in DNA methylation, histone acetylation and histone methylation during tumor progression and highlight the development of inhibitors of or drugs targeted at epigenetic enzymes.

ARHGAP4 regulates the cell migration and invasion of pancreatic cancer by the HDAC2/β-catenin signaling pathway

β-catenin is a subunit of the cadherin protein complex and acts as an intracellular signal transducer in the Wnt signaling pathway that mediates multiple cellular processes, such as cell migration and invasion. HDAC2 (histone deacetylase 2), a deacetylase that maintains histone H3 in a deacetylated state in the promoter region of Wnt-targeted genes where β-catenin is bound, negatively regulating β-catenin activation. However, the regulation of HDAC2/β-catenin pathway remains unclear. Here, we report ARHGAP4 as a new regulator of the β-catenin pathway that regulates cell invasion and migration of pancreatic cancer as well as the downstream effector MMP2 and MMP9 expression in vitro. Mechanistically, ARHGAP4 interacts with and ubiquitinates HDAC2, which in turn inhibits β-catenin activation. Furthermore, treatment of CAY10683, an HDAC2 inhibitor, and XAV939, a Wnt/β-catenin pathway inhibitor, attenuated the effects of ARHGAP4 silencing on pancreatic cancer cells. Overall, our findings establish ARHGAP4 as a novel regulator of HDAC2/β-catenin pathway with a critical role in tumorigenesis.

Epigenetic abnormalities of classical Hodgkin lymphoma and its effect on immune escape

Classical Hodgkin lymphoma (cHL) is a particular kind of malignant tumour that originates from the B cells. The malignant phenotype of cHL is, at least in part, maintained by epigenetic aberrations, which primarily consist of abnormal histone methylation and acetylation. Progress has been made in clinical trials concerning the histone deacetylases inhibitors (HDACis) in cHL. Also, some demethylation regimens could serve the purpose of preventing and treating tumours. Programmed death-ligand receptor 1 (PD-L1, CD274) inhibitors or apoptosis receptor 1 (PD-1, CD279) inhibitors are used in treating patients with relapsed cHL in recent years. Academic researches indicated that PD-1/PD-L1 inhibitors, including nivolumab and pembrolizumab, demonstrate remarkable activity in relapsed cHL. In addition, in recent years, a close association between epigenetic aberrations and immune escape has been explored in cHL. DNA methyltransferase (DNMT) inhibitors, HDACis, and immune checkpoint blockade exhibit synergistic effects. Thus, this review aims to provide an overview on the epigenetic abnormalities of cHL and its effect on immune escape, in order to explore the optimal combination approach to treat the disease. SIGNIFICANCE OF THE STUDY: Cancer Statistics 2018 reported that more than 8000 new cases of Hodgkin lymphoma were diagnosed. In recent years, PD-1/PD-L1 inhibitors for cHL have been utilized, and the therapeutic strategies of HDACis combined with PD-1/PD-L1 inhibitors have been raised. It is critical for improving the efficacy and decreasing the toxicity in treating the patients with cHL.

Prognosis Analysis of Histone Deacetylases mRNA Expression in Ovarian Cancer Patients

Histone deacetylases modulate the dynamic balance of histone acetylation and deacetylation in cells, which participate in epigenetic regulations. Accumulated evidence has demonstrated that histone deacetylases are associated with angiogenesis, cell proliferation and survival in a variety of human cancers. However, the expression and distinct prognostic value of histone deacetylases in ovarian cancer have not been well elucidated. In the present study, we collected the overall survival (OS), progress free survival (PFS), and histone deacetylases (HDAC1-11) mRNA expression in ovarian cancer from the Kaplan-Meier plotter online database. We investigated the relationship between histone deacetylases mRNA level and the clinicopathological parameters of the ovarian cancer patients, such as histology subtypes, clinical stages, grades and TP53 mutation. Our analysis data showed that over-expression of HDAC1, HDAC2, HDAC4, HDAC5 and HDAC11 were correlated to poor overall survival and unfavorable progress free survival in all ovarian cancer patients. Notably, the higher level of HDAC11 was associated with the worse OS and PFS for serous/ stage III+IV/ grade III/ TP53 mutation ovarian cancer patients. In conclusion, HDACs may play a crucial role in the prognosis of ovarian cancer, but it is worth noting that HDAC11 may be a biomarker for poor prognosis in ovarian cancer patients.

MGCD0103 induces apoptosis and simultaneously increases the expression of NF-κB and PD-L1 in classical Hodgkin's lymphoma

At present there is no consensus on the treatment of classical Hodgkin's lymphoma (CHL) following relapse. The aim of the present study was to access the class I-selective histone deacetylase (HDAC) inhibitor (HDACI) MGCD0103 on the expression levels of Bcl-2, nuclear factor (NF)-κB and programmed death-ligand 1 (PD-L1) in CHL, to explore the possible therapeutic value of MGCD0103 in combined relative target drugs for patients with CHL. In L1236 and L428 cell lines, apoptosis and cell cycle stage were identified using flow cytometry, and the effects of HDACI on CHL were assessed in terms of Bcl-2, NF-κB and PD-L1 expression levels, which were detected by western blotting and co-focusing experiments. The results demonstrated that MGCD0103 could induce cell apoptosis and cell cycle arrest, down-regulate Bcl-2 and increase NF-κB and PD-L1 expression levels in L1236 and L428 cell lines. MGCD0103 decreases Bcl-2 levels and upregulates PD-L1, which indicates that the combined use of HDACIs and a PD-L1 inhibitor in theory may improve treatment outcomes in patients with CHL. MGCD0103 may also up-regulate NF-κB, which seems to induce resistance towards anti-apoptotic drugs. Clinical trials combining HDACIs with NF-κB and/or PD-L1 inhibitors should be designed to further improve treatment outcomes for patients with CHL.