Department of Biological Sciences, Bridgewater State University, Bridgewater, Massachusetts, United States of America.
PLoS One. 2023 Jan 26;18(1):e0281009. doi: 10.1371/journal.pone.0281009. eCollection 2023.
Since a majority of ovarian tumors recur in a drug-resistant form leaving patients few treatment options, the goal of this study was to explore phenotypic and molecular characteristics of a cisplatin-resistant ovarian cancer cell line (OVCAR8R) as compared to its cisplatin-sensitive syngeneic counterpart (OVCAR8) and to explore the effectiveness of a novel chemotherapeutic, Withaferin A (WA). In addition to unique morphological characteristics, the small heat shock proteins (Hsps) αB-Crystallin (HspB5) and Hsp27 are constitutively expressed along with increased expression of vimentin in OVCAR8R cells, while OVCAR8 cells do not endogenously express these Hsps, supporting that Hsp overexpression may confer resistance to chemotherapy and promote more aggressive tumor types. WA increases apoptosis in a dose-dependent manner in OVCAR8 cells, while OVCAR8R cells remain more viable at comparable doses of WA coincident with the upregulation of αB-Crystallin. To determine the significance of αB-Crystallin in conferring a more aggressive phenotype, αB-Crystallin was silenced by CRISPR-Cas9 in OVCAR8R cells. The morphology of the OVCAR8R clones in which αB-Crystallin was silenced reverted to the morphology of the original cisplatin-sensitive OVCAR8 cells. Further, cisplatin-resistant OVCAR8R cells constitutively express higher levels of vimentin and migrate more readily than cisplatin-sensitive OVCAR8 and OVCAR8R cells in which αB-Crystallin was silenced. Transient overexpression of wildtype αB-Crystallin, but not a chaperone-defective-mutant, alters the morphology of these cells to closely resemble the cisplatin-resistant OVCAR8R cells and protects versus WA-induced apoptosis. Together, this research supports the potential effectiveness of WA as a therapy for ovarian cancer cells that have not yet acquired resistance to platinum-based therapies, and importantly, underscores that αB-Crystallin contributes to a more aggressive cellular phenotype and as such, may be a promising molecular target for a better clinical outcome.
由于大多数卵巢肿瘤以耐药形式复发，使患者的治疗选择有限，因此本研究的目的是探索顺铂耐药卵巢癌细胞系（OVCAR8R）与顺铂敏感同系物（OVCAR8）相比的表型和分子特征，并探讨新型化疗药物 Withaferin A（WA）的有效性。除了独特的形态特征外，小分子热休克蛋白（Hsps）αB-晶体蛋白（HspB5）和 Hsp27 在 OVCAR8R 细胞中持续表达，同时波形蛋白表达增加，而 OVCAR8 细胞内源性不表达这些 Hsps，支持 Hsp 过表达可能赋予化疗耐药性并促进更具侵袭性的肿瘤类型。WA 以剂量依赖性方式增加 OVCAR8 细胞的凋亡，而 OVCAR8R 细胞在可比剂量的 WA 下仍保持更具活力，同时αB-晶体蛋白上调。为了确定αB-晶体蛋白在赋予更具侵袭性表型方面的意义，通过 CRISPR-Cas9 在 OVCAR8R 细胞中沉默αB-晶体蛋白。沉默αB-晶体蛋白的 OVCAR8R 克隆的形态恢复为原始顺铂敏感的 OVCAR8 细胞的形态。此外，与沉默αB-晶体蛋白的顺铂敏感 OVCAR8 和 OVCAR8R 细胞相比，顺铂耐药的 OVCAR8R 细胞持续表达更高水平的波形蛋白，并且更易于迁移。瞬时过表达野生型αB-晶体蛋白，但不是伴侣缺陷突变体，可改变这些细胞的形态，使其与顺铂耐药的 OVCAR8R 细胞非常相似，并可防止 WA 诱导的凋亡。总的来说，这项研究支持 WA 作为一种治疗尚未对铂类治疗产生耐药性的卵巢癌细胞的潜在有效性，并且重要的是，强调了αB-晶体蛋白有助于更具侵袭性的细胞表型，因此可能是改善临床结果的有前途的分子靶点。
