Targeting LARP1 Enhances Carboplatin Sensitivity and Suppresses Tumor Growth in Endometrial Cancer

Abstract

La-related protein 1 (LARP1) is an RNA-binding protein that post-transcriptionally regulates mRNA with potential oncogenic role in multiple cancers; however, its function in endometrial cancer remains unknown. An analysis of the TCGA endometrial cancer cohort showed that overexpression of LARP1 is associated with shorter overall survival (OS) and progression-free interval (PFI) as indicated by Kaplan-Meier analysis. Functional in vitro studies revealed that LARP1 knockdown by two different siRNAs markedly suppressed cell viability and triggered apoptosis, as confirmed by increased protein levels of cleaved PARP1 and cleaved caspase-3. Mechanistically, LARP1 knockdown remarkably reduced E2F1 protein levels as confirmed by immunofluorescence and Western blotting. Clinically, co-overexpression of LARP1 and E2F1 further decreased OS and PFI, suggesting a co-operative oncogenic axis. Importantly, LARP1 knockdown enhanced the sensitivity of ISHI and HEC-1A endometrial cancer cell lines to carboplatin treatment. These findings suggest that LARP1 promotes endometrial cancer survival and resistance to chemotherapy, at least in part, through the regulation of E2F1 and suppression of apoptosis. Targeting LARP1 could represent a promising therapeutic strategy to suppress tumor growth and enhance sensitivity to platinum-based chemotherapy.