Inhibition of ubiquitin‑specific protease�14 promotes connexin�32 internalization and counteracts cisplatin cytotoxicity in human ovarian cancer cells

Abstract

Although cisplatin is one of the most accepted therapies for ovarian cancer, recurrence and drug resistance remain problematic. Both the ubiquitin-proteasome system (UPS) and connexin (Cx) are closely related to tumor progression. However, the role of ubiquitin-specific protease 14 (USP14) and Cx in mediating drug resistance remains unclear. In the present study, we aimed to determine whether USP14 is involved in cisplatin resistance and modulates the internalization of connexin 32 (Cx32) in ovarian cancer. The results of the deubiquitinase (DUB) trap assay and western blot analysis revealed that the expression and activity levels of USP14 were downregulated in A2780 cisplatin-resistant cells (A2780-CDDP) relative to these levels in A2780 cisplatin-sensitive cells (A2780). CCK-8 assay results showed that inhibition of USP14 by a specific inhibitor or siRNA decreased cisplatin cytotoxicity in A2780 cells. Additionally, USP14 inhibition increased the expression of Cx32 without changing its mRNA and ubiquitination levels, as showed by Real-time qPCR and immunoprecipitation assay respectively. Cisplatin resistance induced by USP14 inhibition was counteracted by Cx32 knockdown. Moreover, USP14 inhibition contributed to Cx32 internalization, as determined by western blot analysis and a reduction in gap junction intercellular communication (GJIC), as showed by parachute dye-coupling assay. Collectively, these data suggest that Cx32 internalization by USP14 inhibition modulates the cisplatin resistance in ovarian cancer cells, thus serving as a potential drug target to challenge chemotherapy failure. In addition, USP14 can also be used as a marker to monitor the development of cisplatin resistance in ovarian cancer treatment.

GJB3: a comprehensive biomarker in pan-cancer prognosis and immunotherapy prediction

“…In the past, connexins have been reported to be associated with cancer grade and stage [ 19 ], with abnormal expression and localization of connexins being associated with cancer initiation and progression. For example, Connexin 43-mediated gap junctions facilitate short-range fibroblast-lung cancer cell interactions, resulting in chemoresistance [ 17 , 20 – 22 ]. As a potential drug target for the failure of chemotherapy, Connexin 32 internalization by USP14 inhibition modulates cisplatin resistance in ovarian cancer cells [ 22 ]; however, little attention has been paid to the role of GJB3 in cancer, especially from a pan-cancer perspective.…”

USP14 promotes the malignant progression and ibrutinib resistance of mantle cell lymphoma by stabilizing XPO1

“…USP14 was involved in cell adhesion-mediated drug resistance in multiple myeloma by acting as a bridge between Bcl-xl apoptosis pathway and Wnt signaling pathway [23]. Inhibition of USP14 promoted connexin 32 internalization and counteracted cisplatin cytotoxicity in human ovarian cancer cells [24]. In addition, US14/UCHL5 inhibitors could cause specific apoptosis in bortezomib or ibrutinib-resistant Waldenstrom macroglobulinemia cells, suggesting that USP14 could be used as a new therapeutic target for Waldenstrom macroglobulinemia [25].…”

Deubiquitinating Enzymes Orchestrate the Cancer Stem Cell-Immunosuppressive Niche Dialogue: New Perspectives and Therapeutic Potential

“…USP14 has been extensively studied because of its overexpression in lung cancer ( Han et al, 2019 ), breast cancer ( Xia et al, 2019a ), ovarian cancer ( Luo et al, 2019 ), and oesophageal squamous cell carcinoma ( Sha et al, 2019 ). It may promote tumorigenesis in approximately 61% of cancers ( Liu B. et al, 2019 ).…”