GSTO1 Promotes Cell Proliferation and Stemness of Cervical Cancer via Activating PI3K / AKT / mTOR Pathway

ABSTRACT

Glutathione S‐transferase omega 1 (GSTO1) is overexpressed in a variety of cancers and plays an important role in the promotion of tumor proliferation and metastasis. Nevertheless, the function of GSTO1 in cervical cancer (CC) is unknown. Immunohistochemistry (IHC) was applied to observe GSTO1 protein levels in CC tissues. Cell proliferation, migration, and invasion capabilities were assessed using CCK8, EdU, plate cloning assays, and Transwell experiments in vitro. Flow cytometry was employed to analyze cell cycle progression and reactive oxygen species (ROS) levels. A subcutaneous xenograft model was utilized to observe cell growth in vivo. Cell stemness was assessed via sphere formation assay. Transcriptome sequencing and enrichment analysis were conducted to explore GSTO1‐related signaling pathways. The proteins linked to cell cycle regulation, stemness, epithelial‐mesenchymal transition (EMT), and the PI3K/AKT/mTOR signaling pathway were identified through western blotting and IHC. In this study, GSTO1 was highly expressed in CC tissues and associated with poor prognosis of patients. Knockdown of GSTO1 suppressed CC cell proliferation in vivo and in vitro and inhibited the cell cycle, stemness, migration, and EMT as in C1‐27 treatment. Conversely, down‐regulation of GSTO1 promoted ROS production in CC cells. RNA sequencing indicated that GSTO1 mediated the activation of the PI3K/AKT signaling pathway. In addition, silencing GSTO1 decreased the phosphorylation of PI3K, AKT, and mTOR proteins. Interestingly, 740 Y‐P (PI3K activator) reversed the inhibitory effects of GSTO1‐induced cell proliferation, cycle, stemness, and EMT via the PI3K/AKT/mTOR signaling axis. GSTO1 was important in CC progression through the PI3K/AKT/mTOR pathway and could serve as a promising therapeutic target.