Rhamnetin, a nutraceutical flavonoid arrests cell cycle progression of human ovarian cancer (SKOV3) cells by inhibiting the histone deacetylase 2 protein

Overexpression of HDAC 2 promotes cell proliferation in ovarian cancer. HDAC 2 is involved in chromatin remodeling, transcriptional repression, and the formation of condensed chromatin structures. Targeting HDAC 2 presents a promising therapeutic approach for correcting cancer-associated epigenetic abnormalities. Consequently, HDAC 2 inhibitors have evolved as an attractive class of anti-cancer agents. This work intended to investigate the anti-cancer abilities and underlying molecular mechanisms of Rhamnetin in human epithelial ovarian carcinoma cells (SKOV3), which remain largely unexplored. We employed various <i>in vitro</i> methods, including MTT, apoptosis study, cell cycle analysis, fluorescence microscopy imaging, and <i>in vitro</i> enzymatic HDAC 2 protein inhibition, to examine the chemotherapeutic sensitivity of Rhamnetin in SKOV3 cells. Additionally, we conducted <i>in silico</i> studies using molecular docking, MD simulation, MM-GBSA, DFT, and pharmacokinetic analysis to investigate the binding interaction mechanism within Rhamnetin and HDAC 2, alongside the compound’s prospective as a lead candidate. The <i>in vitro</i> assay confirmed the cytotoxic effects of Rhamnetin on SKOV3 cells, through its inhibition of HDAC 2 activity. Rhamnetin, a nutraceutical flavonoid, halted at the G1 phase of the cell cycle and triggered apoptosis in SKOV3 cells. Furthermore, computational studies provided additional evidence of its stable binding to the HDAC 2 protein’s binding site cavity. Based on our findings, we conclude that Rhamnetin effectively promotes apoptosis and mitigates the proliferation of SKOV3 cells through HDAC 2 inhibition. These results highlight Rhamnetin as a potential lead compound, opening a new therapeutic strategy for human epithelial ovarian cancer. Communicated by Ramaswamy H. Sarma

组蛋白去乙酰化酶2（HDAC 2）的过表达可促进卵巢癌细胞增殖。HDAC 2参与染色质重塑、转录抑制以及浓缩染色质结构的形成。靶向HDAC 2是纠正癌症相关表观遗传异常的极具潜力的治疗策略，因此HDAC 2抑制剂已发展为一类极具吸引力的抗癌药物。本研究旨在探究鼠李素（Rhamnetin）在人类上皮性卵巢癌细胞（SKOV3）中的抗癌活性及其潜在分子机制，而目前针对该领域的研究仍较为匮乏。本研究采用多种体外实验（in vitro）方法，包括MTT比色法、凋亡检测、细胞周期分析、荧光显微镜成像以及体外HDAC 2酶活性抑制实验，以探究鼠李素对SKOV3细胞的化疗敏感性影响。此外，本研究还开展了计算机模拟实验（in silico），通过分子对接、分子动力学（MD）模拟、MM-GBSA自由能计算、密度泛函理论（DFT）以及药代动力学分析，探究鼠李素与HDAC 2的结合相互作用机制，并评估该化合物作为先导候选药物的潜力。体外实验结果证实，鼠李素可通过抑制HDAC 2活性，对SKOV3细胞产生细胞毒性作用。作为一种营养保健类黄酮化合物，鼠李素可使SKOV3细胞阻滞于细胞周期G1期，并诱导其发生凋亡。此外，计算机模拟实验进一步证实，鼠李素可稳定结合于HDAC 2蛋白的结合位点空腔内。基于本研究结果，我们认为鼠李素可通过抑制HDAC 2活性，有效诱导SKOV3细胞凋亡并抑制其增殖。上述研究结果表明，鼠李素是一种具有潜力的先导化合物，为人类上皮性卵巢癌的治疗提供了新的策略。本文由Ramaswamy H. Sarma转交刊发。