Abstract 396: Therapeutic targeting of eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) in enzalutamide resistant (ENZR) prostate cancer

Abstract

Abstract Objective: Deregulation of the translation initiation machinery is one of the critical steps for oncogenic mRNA translation in tumor cells. Eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) is a crucial scaffold of translation initiation complex (EIF4F). Our recent studies suggest a role for EIF4G1 in multiple tumor types including prostate cancer progression. In the present study, we tested the unknown function of EIF4G1 in Enzalutamide resistant prostate cancer cells. Methods: We used enzalutamide resistant C4-2B (C4-2BENZR) and parental C4-2B cells for the current study. For the functional studies, we used shRNA targeting the EIF4G1 and pharmacological EIF4G-EIF4E complex inhibitor (4EGI-1). The functional assays such as clonogenic, cell proliferation, cell viability, trans-well migration/invasion, and prostasphere formation were performed. To further expand in vitro findings we employed, in-vivo tumor xenograft model derived from enzalutamide resistance C4-2B cells. Results: We found a higher level of EIF4G1 protein in ENZ resistance (C4-2B ENZR) cell lines as compared to parental C4-2B cell lines. Furthermore, knockdown of EIF4G1 by shRNA or treatment with 4EGI-1 inhibitor impaired the clonogenic potential, prostasphere formation, cell viability/proliferation, and cell migration/invasion in C4-2B ENZR cell line, suggesting a critical role of EIF4G1 in modulating enzalutamide resistance in CRPC cells. C4-2BENZR subcutaneous tumor xenograft treated with
combination of 4EGI-1 and ENZ were significantly reduced the tumor volume. Moreover 4EGI-1 sensitized ENZ Resistance C4-2B cells to Enzalutamide treatment in tumor xenograft model. Conclusions: Overall, the findings suggest that EIF4G1 could serve as a novel therapeutic target in overcoming therapeutic resistance to current treatments in PCa. Citation Format: Praveen K. Jaiswal, Sweaty Koul, Saikolappan Sankaralingam, Hari K. Koul. Therapeutic targeting of eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) in enzalutamide resistant (ENZR) prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 396.