Abstract
This study investigates the role of Gαi3 in bladder cancer, focusing on its expression, functions, and mechanisms. Bioinformatics reveal that Gαi3 is overexpressed in bladder cancer, linked to poorer survival and higher tumor grades. Single-cell sequencing data confirm Gαi3 overexpression in bladder cancer epithelial cells. Additionally, Gαi3 is upregulated in tissues from locally treated patients and various bladder cancer cells. Silencing Gαi3 with targeted shRNA inhibited cell proliferation, migration, and invasion, activating caspase-mediated apoptosis. CRISPR/Cas9-mediated knockout of Gαi3 also exhibited significant anti-cancer effects, while overexpression enhanced cell proliferation and mobility. Gαi3 activates the Akt-mTOR pathway; silencing or knockout reduced phosphorylation of Akt and S6K, while overexpression increased it. The anti-cancer effects of Gαi3 shRNA were lessened by reactivating Akt-mTOR with a constitutively active Akt1 mutant. We observed a stronger binding affinity between the Gαi3 promoter and the transcription factor GATA4 in bladder cancer tissues. GATA4 silencing lowered Gαi3 expression, while GATA4 overexpression increased it. In vivo, Gαi3 silencing significantly hindered the growth of bladder cancer xenografts in nude mice, along with inactivation of the Akt-mTOR pathway and increased apoptosis. These results highlight Gαi3's functional role in bladder cancer progression.