Phytoestrogens and related microbial metabolites remodel aberrant prostate transcriptomic profiles generated upon exposure to oxidative stress.

Dietary phytoestrogens, including pterostilbene (PTS) from berries and genistein (GEN) from soybeans, exert anti-oxidant and anti-inflammatory effects in prostate cancer. However, the specific actions in regulation of cell biology and homeostasis in normal prostate epithelial cells remain unknown and a prominent research gap refers to the effects of related microbial metabolites of phytoestrogens. We therefore explored effects of distinct phytoestrogens, PTS and GEN, and PTS microbial metabolite, pinostilbene (PNS), in healthy cells with disrupted homeostasis. Human RWPE-1 prostate epithelial cells were treated with 100 µM concentration of hydrogen peroxide (H2O2). The H2O2-challenged cells were then exposed to phytoestrogens, followed by RNA sequencing. Transcriptomics revealed 1,770 differentially expressed genes (DEGs) upon H2O2 exposure. Upregulated genes were functionally implicated in immune signaling and inflammatory pathways, whereas downregulated genes were linked to autophagy, homeostasis, and cellular architecture. A quantitative metric termed the Weighted Recovery Ratio (WRR) was developed to quantify the extent that the treatment reversed gene expression change induced upon H₂O₂ challenge. WRR indicated that PNS recovered the highest number of H2O2-responsive genes. Among all PTS and PNS DEGs, 47% and 69%, respectively, constituted partially or fully recovered H2O2-responsive genes. This fraction was only 9% for GEN. PTS and PNS, but not GEN, recovered genes involved in DNA methylation/demethylation, which suggests restoration of DNA methylation equilibrium that was disrupted by H2O2. Our findings provide a novel tool to quantify the relative efficacy of phytoestrogens in attenuating alterations caused by an oxidative stressor. We present evidence for differential action of phytoestrogens with distinct chemical structures and for more potent action of microbial metabolites derived from phytoestrogens.