New developments in the treatment of peripheral T-cell lymphoma - role of Belinostat

Update on histone deacetylase inhibitors in peripheral T-cell lymphoma (PTCL)

Peripheral T-cell lymphomas (PTCLs) are a group of highly aggressive malignancies with generally poor prognoses, and the first-line chemotherapy of PTCL has limited efficacy. Currently, several novel targeted agents, including histone deacetylase inhibitors (HDACis), have been investigated to improve the therapeutic outcome of PTCLs. Several HDACis, such as romidepsin, belinostat, and chidamide, have demonstrated favorable clinical efficacy and safety in PTCLs. More novel HDACis and new combination therapies are undergoing preclinical or clinical trials. Mutation analysis based on next-generation sequencing may advance our understanding of the correlation between epigenetic mutation profiles and relevant targeted therapies. Multitargeted HDACis and HDACi-based prodrugs hold promising futures and offer further directions for drug design.

Dissecting Histone Deacetylase 3 in Multiple Disease Conditions: Selective Inhibition as a Promising Therapeutic Strategy

The acetylation of histone and non-histone proteins has been implicated in several disease states. Modulation of such epigenetic modifications has therefore made histone deacetylases (HDACs) important drug targets. HDAC3, among various class I HDACs, has been signified as a potentially validated target in multiple diseases, namely, cancer, neurodegenerative diseases, diabetes, obesity, cardiovascular disorders, autoimmune diseases, inflammatory diseases, parasitic infections, and HIV. However, only a handful of HDAC3-selective inhibitors have been reported in spite of continuous efforts in design and development of HDAC3-selective inhibitors. In this Perspective, the roles of HDAC3 in various diseases as well as numerous potent and HDAC3-selective inhibitors have been discussed in detail. It will surely open up a new vista in the discovery of newer, more effective, and more selective HDAC3 inhibitors.

Epigenetic alterations and advancement of treatment in peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) is a rare and heterogeneous group of clinically aggressive diseases associated with poor prognosis. Except for ALK + anaplastic large-cell lymphoma (ALCL), most peripheral T-cell lymphomas are highly malignant and have an aggressive disease course and poor clinical outcomes, with a poor remission rate and frequent relapse after first-line treatment. Aberrant epigenetic alterations play an important role in the pathogenesis and development of specific types of peripheral T-cell lymphoma, including the regulation of the expression of genes and signal transduction. The most common epigenetic alterations are DNA methylation and histone modification. Histone modification alters the level of gene expression by regulating the acetylation status of lysine residues on the promoter surrounding histones, often leading to the silencing of tumour suppressor genes or the overexpression of proto-oncogenes in lymphoma. DNA methylation refers to CpG islands, generally leading to tumour suppressor gene transcriptional silencing. Genetic studies have also shown that some recurrent mutations in genes involved in the epigenetic machinery, including TET2, IDH2-R172, DNMT3A, RHOA, CD28, IDH2, TET2, MLL2, KMT2A, KDM6A, CREBBP, and EP300, have been observed in cases of PTCL. The aberrant expression of miRNAs has also gradually become a diagnostic biomarker. These provide a reasonable molecular mechanism for epigenetic modifying drugs in the treatment of PTCL. As epigenetic drugs implicated in lymphoma have been continually reported in recent years, many new ideas for the diagnosis, treatment, and prognosis of PTCL originate from epigenetics in recent years. Novel epigenetic-targeted drugs have shown good tolerance and therapeutic effects in the treatment of peripheral T-cell lymphoma as monotherapy or combination therapy. NCCN Clinical Practice Guidelines also recommended epigenetic drugs for PTCL subtypes as second-line therapy. Epigenetic mechanisms provide new directions and therapeutic strategies for the research and treatment of peripheral T-cell lymphoma. Therefore, this paper mainly reviews the epigenetic changes in the pathogenesis of peripheral T-cell lymphoma and the advancement of epigenetic-targeted drugs in the treatment of peripheral T-cell lymphoma (PTCL).

Belinostat suppresses cell proliferation by inactivating Wnt/β-catenin pathway and promotes apoptosis through regulating PKC pathway in breast cancer

Belinostat is a histone deacetylase inhibitor drug capable of regulating cell growth in diverse cancers. Nonetheless, little information clarified the role of Belinostat in breast cancer. Hence, the functions of Belinostat in breast cancer cells survival was disclosed in this study. Belinostat at 50 and 100 μM were applied to manage MCF-7 cells, cell viability, Ki67 positive cells, cell cycle and apoptosis were monitored via MTT, immunohistochemistry and flow cytometry. Furthermore, the apoptosis-related factors, Wnt/β-catenin pathway and PKC pathway were tested through western blot and qRT-PCR. Lastly, in vivo effect of Belinostat was determined by a murine model. The results showed that Belinostat dampened cell viability, decreased the proportion of Ki67 positive cells and arrested cells at G0/G1 phase. The decreases of Wnt/β-catenin, CCND2 and Myc were observed in MCF-7 cells after Belinostat stimulation. Additionally, Belinostat induced cell apoptosis, meanwhile dampened Bcl-2 and raised Bax and Cleaved caspase 3 in a dose and time-dependent manner. Additionally, Belinostat activated PKC pathway by upgrading PKCδ and P53 expressions. Furthermore, Belinostat restrained tumour weight and volume in vivo. In summary, this study depicted that Belinostat prohibited proliferation and evoked apoptosis via mediating Wnt/β-catenin and PKC pathways in MCF-7 cells.

Chemosensitizer effect of cisplatin-treated bladder cancer cells by phenazine-5,10-dioxides

We determined the chemosensitizer effect of phenazine dioxide derivatives to cisplatin and the possible mechanism of action on bladder cancer cells. Anti-proliferative activity of nine phenazine dioxide derivatives in presence or absence of cisplatin was evaluated in two bladder tumor human cells T24 and 253 J and one non tumor cell line V79-4. The sensitizer effect of the combined treatment was determined by chromosomal aberrations and micronucleus test. A possible mechanism of action of the sensitizer compounds as HDACi was also investigated.The phenazine dioxide 2c combined with cisplatin induced a cell cycle arrest on bladder cancer cells and resensitize the invasive and cisplatin resistant 253 J cell line. The HDAC inhibitory activity appears as one of the mechanism of action of the compound. The low toxicity levels against normal cells point out the phenazine dioxide derivative 2c as a very good scaffold for further design of HDACi sensitizer agents.

Downregulation of HDAC3 by ginsenoside Rg3 inhibits epithelial-mesenchymal transition of cutaneous squamous cell carcinoma through c-Jun acetylation

The metastatic rate of human cutaneous squamous cell carcinoma (CSCC) has increased in recent years. Despite the current advances in therapies, effective treatments remain lacking. Ginsenoside 20(R)-Rg3 is an effective antitumor monomer extracted from ginseng, but the role of Rg3 in CSCC remains unknown. It has been reported that aberrantly elevated histone deacetylase 3 (HDAC3) is involved in tumor malignancy in multiple malignant tumors. However, the effects of HDAC3 on the regulation of c-Jun acetylation in tumor epithelial-mesenchymal transition (EMT) and migration have not been clearly illuminated. In our research, the immunohistochemistry staining results of skin tissue microarrays showed that HDAC3 staining was increased in CSCC compared with the normal dermal tissue. Then, we found that Rg3 treatment (25 and 50 μg/ml) inhibited CSCC cell (A431 and SCC12 cells) EMT through increasing E-cadherin and decreasing N-cadherin, vimentin, and Snail expression. Wound-healing and transwell assays showed that Rg3 could inhibit migration. Meanwhile, Rg3 significantly downregulated the expression of HDAC3 in CSCC cells as detected by real-time quantitative PCR, western blot, and immunofluorescence. Importantly, c-Jun acetylation was increased by the downregulation of HDAC3 with HDAC3 shRNA, and the downregulation was associated with CSCC cell EMT inhibition. Collectively, our results showed that downregulation of HDAC3 by Rg3 or shHDAC3 treatment resulted in c-Jun acetylation, which in turn inhibited CSCC cell EMT. These results indicate that HDAC3 could potentially serve as a therapeutic target therapeutic target for CSCC. Rg3 is an attractive and efficient agent that has oncotherapeutic effects and requires further investigation.

Toward Multi-Targeted Platinum and Ruthenium Drugs-A New Paradigm in Cancer Drug Treatment Regimens?

While medicinal inorganic chemistry has been practised for over 5000 years, it was not until the late 1800s when Alfred Werner published his ground-breaking research on coordination chemistry that we began to truly understand the nature of the coordination bond and the structures and stereochemistries of metal complexes. We can now readily manipulate and fine-tune their properties. This had led to a multitude of complexes with wide-ranging biomedical applications. This review will focus on the use and potential of metal complexes as important therapeutic agents for the treatment of cancer. With major advances in technologies and a deeper understanding of the human genome, we are now in a strong position to more fully understand carcinogenesis at a molecular level. We can now also rationally design and develop drug molecules that can either selectively enhance or disrupt key biological processes and, in doing so, optimize their therapeutic potential. This has heralded a new era in drug design in which we are moving from a single- toward a multitargeted approach. This approach lies at the very heart of medicinal inorganic chemistry. In this review, we have endeavored to showcase how a "multitargeted" approach to drug design has led to new families of metallodrugs which may not only reduce systemic toxicities associated with modern day chemotherapeutics but also address resistance issues that are plaguing many chemotherapeutic regimens. We have focused our attention on metallodrugs incorporating platinum and ruthenium ions given that complexes containing these metal ions are already in clinical use or have advanced to clinical trials as anticancer agents. The "multitargeted" complexes described herein not only target DNA but also contain either vectors to enable them to target cancer cells selectively and/or moieties that target enzymes, peptides, and intracellular proteins. Multitargeted complexes which have been designed to target the mitochondria or complexes inspired by natural product activity are also described. A summary of advances in this field over the past decade or so will be provided.

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.