Hedgehog pathway orchestrates the interplay of histone modifications and tailors combination epigenetic therapies in breast cancer

Epigenetic therapies that cause genome-wide epigenetic alterations, could trigger local interplay between different histone marks, leading to a switch of transcriptional outcome and therapeutic responses of epigenetic treatment. However, in human cancers with diverse oncogenic activation, how oncogenic pathways cooperate with epigenetic modifiers to regulate the histone mark interplay is poorly understood. We herein discover that the hedgehog (Hh) pathway reprograms the histone methylation landscape in breast cancer, especially in triple-negative breast cancer (TNBC). This facilitates the histone acetylation caused by histone deacetylase (HDAC) inhibitors and gives rise to new therapeutic vulnerability of combination therapies. Specifically, overexpression of zinc finger protein of the cerebellum 1 (ZIC1) in breast cancer promotes Hh activation, facilitating the switch of H3K27 methylation (H3K27me) to acetylation (H3K27ac). The mutually exclusive relationship of H3K27me and H3K27ac allows their functional interplay at oncogenic gene locus and switches therapeutic outcomes. Using multiple in vivo breast cancer models including patient-derived TNBC xenograft, we show that Hh signaling-orchestrated H3K27me and H3K27ac interplay tailors combination epigenetic drugs in treating breast cancer. Together, this study reveals the new role of Hh signaling-regulated histone modifications interplay in responding to HDAC inhibitors and suggests new epigenetically-targeted therapeutic solutions for treating TNBC.

Antifungal activity study on HDAC inhibitor Rocilinostat / 药学实践杂志

Objective To evaluate the in vitro synergistic antifungal activity of HDAC inhibitors in combination with azole drugs against azoles-resistant Candida strains. Methods The checkerboard microdilution method was used to evaluate the antifungal activity of the HDAC inhibitors in combination with azole drugs against clinically drug-resistant strains. The fungistatic activity and toxicity of Rocilinostat was determined through time-growth curve assay and cytotoxicity assay. Results The compound Rocilinostat combined with azole drugs showed excellent synergistic antifungal activity against a variety of azoles-resistant Candida albicans and Candida glabrata. The combination of high concentration Rocilinostat with FLC exhibited fungistatic effects. Very low toxicity was detected with Rocilinostat towards normal cells. Rocilinostat showed better HDAC inhibitory activity than SAHA. Conclusion As a fungi HDAC inhibitor, Rocilinostat has excellent in vitro synergistic antifungal activity and no severe toxicity to normal human cells.

Short-chain Fatty Acids Inhibit Staphylococcal Lipoprotein-induced Nitric Oxide Production in Murine Macrophages

Staphylococcus aureus, a Gram-positive pathogen, can cause severe inflammation in humans, leading to various life-threatening diseases. The lipoprotein is a major virulence factor in S. aureus-induced infectious diseases and is responsible for excessive inflammatory mediators such as nitric oxide (NO). Short-chain fatty acids (SCFAs) including butyrate, propionate, and acetate are microbial metabolites in the gut that are known to have anti-inflammatory effects in the host. In this study, we investigated the effects of SCFAs on S. aureus lipoprotein (Sa.LPP)-induced NO production in mouse macrophages. Butyrate and propionate, but not acetate, inhibited Sa.LPP-induced production of NO in RAW 264.7 cells and bone marrow-derived macrophages. Butyrate and propionate inhibited Sa.LPP-induced expression of inducible NO synthase (iNOS). However, acetate did not show such effects under the same conditions. Furthermore, butyrate and propionate, but not acetate, inhibited Sa.LPP-induced activation of NF-κB, expression of IFN-β, and phosphorylation of STAT1, which are essential for inducing transcription of iNOS in macrophages. In addition, butyrate and propionate induced histone acetylation at lysine residues in the presence of Sa.LPP in RAW 264.7 cells. Moreover, Sa.LPP-induced NO production was decreased by histone deacetylase (HDAC) inhibitors. Collectively, these results suggest that butyrate and propionate ameliorate the inflammatory responses caused by S. aureus through the inhibition of NF-κB, IFN-β/STAT1, and HDAC, resulting in attenuated NO production in macrophages.

Epigenetic Modifications: Therapeutic Potential in Cancer

Epigenetic modifications and alterations in chromatin structure and function contribute to the cumulative changes observed as normal cells undergo malignant transformation. These modifications and enzymes (DNA methyltransferases, histone deacetylases, histone methyltransferases, and demethylases) related to them have been deeply studied to develop new drugs, epigenome-targeted therapies and new diagnostic tools. Epigenetic modifiers aim to restore normal epigenetic modification patterns through the inhibition of epigenetic modifier enzymes. Four of them (azacitidine, decitabine, vorinostat and romidepsin) are approved by the U.S. Food and Drug Administration. This article provides an overview about the known functional roles of epigenetic enzymes in cancer development.

Development of epigenetic treatment in myelodysplastic syndromes / 白血病·淋巴瘤

It have been known that many epigenetic alterations palyed an important role in development of myelodysplastic syndromes (MDS). In contrast to genetic alterations, epigenetic alterations could be in principle pharmacologically reversed. Application of epigenetic drugs can reactivate inactivated suppressor genes. Epigenetic drugs mainly include demethylating agents and histone deacylase (HDAC) inhibitors, which are available in treatment. 5-AZA and decitabine as DNA demethylation agents have been approved by FDAof treatment in intermediate or high risk MDS, especially those old patients who are resistant to chemotherapy.HDAC inhibitors such as valproic acid are mostly employed in phase I trial, probably effective in treating low risk MDS, but treatment schedules and curative effects still have to be evaluated. The combination of demethylation agents and HDAC inhibitors may result in synergistic activity, but its therapeutic effect seems not to be superior to monotherapy of demethylation agents in current clinical trials, and it still need new clinical trials containing more cases and rational treatment schedules to identify safety and effect of combination.