Global gene expression regulation mediated by tgf-ẞ through h3k4me3 and h3k9me3 mark in prostate cancer.

Abstract

Transforming Growth Factor Beta (TGF-B) expression is a significant biomarker associated with poor prognosis in prostate cancer. TGF-ẞ demonstrates a dual role, acting as a tumor suppressor in the initial stages of cancer and promoting metastasis in advanced stages. While the molecular mechanisms of TGF-ẞ's actions are largely understood through canonical and non-canonical signal transduction pathways, the epigenetic mechanisms that translate transient TGF-ẞ stimulation into stable gene expression changes remain unclear. This study aims to elucidate the impact of TGF-ẞ signalling on histone modifications histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 trimethylation (H3K9me3), and their roles in global gene regulation. Prostate cancer cells were treated with TGF-ẞ, and chromatin immunoprecipitation followed by sequencing (ChIP-Seq) was performed to investigate genome-wide changes in H3K4me3 and H3K9me3 distribution. Comparative analysis was conducted with interferon-gamma (IFNy) stimulated/unstimulated HeLa cells to identify common and specific gene regulation patterns. Functional annotation and motif analysis were performed using DAVID and MEME-ChIP tools. TGF-ẞ stimulation led to significant changes in H3K4me3 occupancy, particularly increasing enrichment on genes involved in transcription regulation, intracellular protein transport, EMT, angiogenesis, and other crucial processes. A positive feedback loop was suggested by the induction of H3K4me3 on TGF-ẞ's own ligands (e.g., GDF1, INHBB, GDF3, GDF6, BMP5). TGF-B-induced H3K4me3 modifications correlated strongly with the transcriptional activation of associated genes, impacting promoter, intronic, and distal intergenic regions. This demonstrates TGF-ẞ's role in acute epigenetic reprogramming. The comparative analysis revealed overlapping and distinct epigenetic modifications in response to TGF-ẞ and IFNy stimulation. Shared genes showed involvement in miRNA-mediated gene silencing, ERK cascade regulation, hypoxia-induced apoptosis, and translational regulation. TGF-B-induced H3K9me3 modifications showed an increase at intronic regions after short-term stimulation and at distal intergenic regions after long-term stimulation. We also found evidence for a possible association of SLC transporters with H3K9me3 mark in presence of TGF-ẞ during tumorigenesis. This suggests a role for H3K9me3 in TGF-B-induced cell migration and adhesion, counter to its traditionally repressive nature. The H3K4 methyltransferase inhibitor, MM-102, was found to counteract TGF-ẞ-induced epithelial-mesenchymal transition (EMT) by downregulating key EMT markers (Ncadherin, SNAIL, Twist, Vimentin). This inhibition significantly impaired the migratory and invasive capacities of prostate cancer cells, underscoring the therapeutic potential of MM-102. This study provides compelling evidence that TGF-B signalling influences the epigenetic marks H3K4me3 and H3K9me3 in prostate cancer causing modulation of global gene expression. The findings also highlight potential therapeutic targets for inhibiting TGF-B-induced metastasis, offering new insights into the epigenetic regulation of cancer progression.