Odd-skipped related 1 plays a tumor suppressor role in ovarian cancer via promoting follistatin-like protein 1 transcription

Zinc-finger transcription factor odd-skipped related 1 (OSR1) is involved in the progression of certain types of cancers, via regulating the transcription of downstream genes. However, the function of OSR1 in ovarian cancer (OC) progression remains unclear. The present study aimed to explore the OSR1 expression pattern in OC tissues and cell lines. Functional assays were performed to explore the regulatory effects of OSR1 on OC cell growth, migration and invasion in vitro and in vivo. Results of the present study demonstrated that OSR1 was significantly downregulated in OC tissues compared with healthy ovarian tissues (P < 0.01). Moreover, SKOV-3 and OVCAR-3 cells with low OSR1 expression were used for functional studies, and results demonstrated that OSR1 overexpression suppressed cell growth by inhibiting cell cycle progression and inducing cell apoptosis in vitro. OC cells with higher OSR1 expression levels exhibited reduced levels of migration and invasion, when compared with the corresponding control. In addition, OSR1 expression in xenografts models resulted in diminished tumor volume and suppressed tumorigenesis. OSR1 enhanced follistatin-like protein 1 (FSTL1) expression at the transcriptional level through directly binding to the promoter of FSTL1, which was commonly reported to exert a tumor suppressor role in OC progression. Moreover, FSTL1 knockdown reversed the action of OSR1 overexpression in OC progression, including cell viability, migration, invasion, and apoptosis. In conclusion, these results indicated that OSR1 may function as a tumor suppressor through augmenting FSTL1 transcription in OC progression, suggesting that the OSR1/ FSTL1 axis may exhibit potential as a therapeutic target for OC therapy.