Jing Su

LRPPRC-Driven Oxidative Phosphorylation Is Associated with Elesclomol-Induced Cuproptosis in Ovarian Cancer

Mitochondrial oxidative phosphorylation serves as a critical driving force in the progression of ovarian cancer. Recent studies have demonstrated that copper induces mitochondrial-dependent programmed cell death by directly binding to the thioacylated components of the tricarboxylic acid (TCA) cycle. The involvement of copper in OXPHOS complex IV, a rate-limiting step in the mitochondrial respiratory chain, suggests that the role of mitochondria in mediating copper-induced cell death can be further elucidated through the study of OXPHOS complex IV. The findings of this study indicate that the cuproptosis process in ovarian cancer, induced by Elesclomol, is associated with mitochondrial complex IV, with LRPPRC identified as a crucial factor. Following Elesclomol treatment of ovarian cancer cells, there was a notable increase in mitochondrial reactive oxygen species (ROS), a significant accumulation of the copper death marker protein DLAT, and a marked decrease in the lipoic acid synthesis-related protein FDX1. Furthermore, the expression levels of copper ion transporters ATP7B and CTR1, which are involved in the assembly and translation of complex IV, as well as the core subunit MTCO1 of complex IV, the copper chaperone protein SCO1, and the interacting protein LRPPRC, were significantly diminished. Inhibition of the IV-stabilizing protein LRPPRC in the ovarian cancer cell lines A2780 and SKOV3 through RNA interference resulted in increased sensitivity to Elesclomol. Concurrently, the expression levels of FDX1, LIAS, LIPT1, SCO1, and MTCO1 decreased significantly. These findings suggest that LRPPRC plays a role in inhibiting the expression of lipoic acid and copper chaperone proteins during Elesclomol-induced copper death in ovarian cancer. This inhibition collectively diminishes the expression and activity changes in complex IV, induces mitochondrial dysfunction, and promotes cuproptosis in ovarian cancer. This study further demonstrates that inhibiting the oxidative phosphorylation complex IV can enhance copper-induced cell death in ovarian cancer.

The Roles of Histone Deacetylases in the Regulation of Ovarian Cancer Metastasis

Ovarian cancer is the most lethal gynecologic malignancy, and metastasis is the major cause of death in patients with ovarian cancer, which is regulated by the coordinated interplay of genetic and epigenetic mechanisms. Histone deacetylases (HDACs) are enzymes that can catalyze the deacetylation of histone and some non-histone proteins and that are involved in the regulation of a variety of biological processes via the regulation of gene transcription and the functions of non-histone proteins such as transcription factors and enzymes. Aberrant expressions of HDACs are common in ovarian cancer. Many studies have found that HDACs are involved in regulating a variety of events associated with ovarian cancer metastasis, including cell migration, invasion, and the epithelial–mesenchymal transformation. Herein, we provide a brief overview of ovarian cancer metastasis and the dysregulated expression of HDACs in ovarian cancer. In addition, we discuss the roles of HDACs in the regulation of ovarian cancer metastasis. Finally, we discuss the development of compounds that target HDACs and highlight their importance in the future of ovarian cancer therapy.

The Nrf2/PGC1α Pathway Regulates Antioxidant and Proteasomal Activity to Alter Cisplatin Sensitivity in Ovarian Cancer

Drug resistance remains a barrier in the clinical treatment of ovarian cancer. Proteasomal and antioxidant activities play important roles in tumor drug resistance, and increasing evidence suggests the existence of an interaction between antioxidant and proteasomal activities. However, the mechanism of the synergistic effects of proteasomal activity and antioxidation on tumor drug resistance is not completely clear. In this study, we compared two ovarian cancer cells, A2780 and SKOV3 cells. Among them, SKOV3 cell is a human clear cell carcinoma cell line that is resistant to platinum. We found that compared with the findings in A2780 cells, SKOV3 cells were less sensitive to both proteasomal inhibitor and cisplatin. Proteasomal inhibition enhanced the sensitivity of A2780 cells, but not SKOV3 cells, to cisplatin. Notably, the Nrf2-mediated antioxidant pathway was identified as a resistance mechanism in proteasome inhibitor-resistant cells, but this was not the only factor identified in our research. In SKOV3 cells, PGC1α regulated the antioxidant activity of Nrf2 by increasing the phosphorylation of GSK3β, and in turn, Nrf2 regulated the transcriptional activity of PGC1α. Thus, Nrf2 and PGC1α synergistically participate in the regulation of proteasomal activity. Furthermore, the Nrf2/PGC1α pathway participated in the regulation of mitochondrial function and homeostasis, further regulating proteasomal activity in SKOV3 cells. Therefore, exploring the roles of PGC1α and Nrf2 in the regulation of proteasomal activity by antioxidant and mitochondrial functions may provide new avenues for reversing drug resistance in ovarian cancer.

An Experimentally Induced Mutation in the UBA Domain of p62 Changes the Sensitivity of Cisplatin by Up-Regulating HK2 Localisation on the Mitochondria and Increasing Mitophagy in A2780 Ovarian Cancer Cells

The study of cisplatin sensitivity is the key to the development of ovarian cancer treatment strategies. Mitochondria are one of the main targets of cisplatin, its self-clearing ability plays an important role in determining the fate of ovarian cancer cells. First, we proved that the sensitivity of ovarian cancer cells to cisplatin depends on mitophagy, and p62 acts as a broad autophagy receptor to regulate this process. However, p62′s regulation of mitophagy does not depend on its location on the mitochondria. Our research shows that the mutation of the UBA domain of p62 increases the localisation of HK2 on the mitochondria, thereby increasing the phosphorylated ubiquitin form of parkin, then stabilising the process of mitophagy and ultimately cell survival. Collectively, our results showed that a mutation in the UBA domain of p62 regulates the level of apoptosis stimulated by cisplatin in ovarian cancer.