SPOP attenuates the proliferation, invasion, and migration of choriocarcinoma JAR cells by promoting KIF23 degradation

Abstract

Abstract Objectives Choriocarcinoma is a highly malignant and aggressive trophoblastic tumor. In our previous study, we discovered that the speckle-type POZ protein (SPOP), which recognizes substrates of E3 ubiquitin ligase, plays a crucial role in trophoblast-derived choriocarcinoma cell lines. Therefore, we investigated the correlation between SPOP and the substrate kinesin-like protein KIF23, as well as the role of KIF23 in choriocarcinoma cells. Methods We constructed JAR cells overexpressing SPOP using lentiviral vectors and subsequently screened the related proteins through ubiquitination-modified quantitative proteomic analysis. The relationship between KIF23 and SPOP was determined using western blotting, and CCK-8, plate cloning, flow cytometry, and Transwell assays were used to investigate the effects of KIF23 and SPOP/KIF23. Results We identified the KIF23 protein and observed that SPOP promoted its degradation. The abundance of KIF23 increased after the addition of the protease inhibitor MG132. KIF23 was highly expressed in choriocarcinoma cells. Compared with JAR cells transfected with NC–small-interfering RNA (siRNA), the proliferation, invasion, migration, and percentage of G0/G1 cells in the KIF23-siRNA group were significantly lower, and the activation of the Akt/GSK3β signaling pathway was markedly attenuated. Additionally, the sh-SPOP+KIF23-siRNA group exhibited significantly inhibited JAR cell proliferation, invasion, and migration, along with clearly attenuated activation of the Akt/GSK3β signaling pathway. Conclusions SPOP attenuates the proliferation, invasion, and migration of choriocarcinoma JAR cells by promoting KIF23 degradation.