Abstract 5347: miR-15a & miR-20b enhance sorafenib sensitivity of hepatocellular carcinoma through repressing CDC37L1 and consequent PPIA downregulation

Abstract

Abstract Sorafenib is a classical targeted drug for the treatment of advanced hepatocellular carcinoma (HCC), but intrinsic resistance severely limits its therapeutic effects. In the present study, we aimed to identify crucial genes in HCC cells that affect sorafenib resistance by a CRISPR/Cas9 genome-scale screening. Among the candidates, two miRNAs, miR-15a and miR-20b, were finally identified as the essential sorafenib-sensitizing genes of HCC cells. In parallel, Cell Counting Kit-8 (CCK-8) assay,colony formation assays and flow cytometric analysis were carried out to assess cell proliferation and survival, whereas tumor growth in vivo was assessed using xenograft models. The results indicated that the deficiency of miR-15a and miR-20b contributed to sorafenib resistance of HCC cells. By combination of various bioinformatics tools, Cell division cycle 37 like 1 (CDC37L1) was identified as a common target gene of miR-15a and miR-20b. Further cellular and molecular biology experiments demonstrated CDC37L1 was negatively regulated by the two miRNAs, and CDC37L1 could enhance sorafenib resistance of HCC in vitro and in vivo. Mechanistically, we carried out SDS-PAGE and silver staining assays followed by mass spectrometry to analyze the immunoprecipitated proteins of CDC37L1. Our findings indicated that CDC37L1, as a cochaperone, effectively increased the expression of PPIA through strengthen the binding between HSP90 and PPIA. Additionally, CDC37L1 and PPIA expression were examined in a tissue microarray containing 80 pairs of HCC and normal tissues derived from patients who received sorafenib treatment via immunohistochemistry (IHC) staining, the results revealed a positive association between CDC37L1 and PPIA expression, and high expression of CDC37L1 and PPIA predicted worse prognosis of HCC patients after sorafenib therapy. Taken together, our findings suggest that both miR-15a and miR-20b play sorafenib-sensitizing roles in HCC by facilitating the complex of CDC37L1/HSP90/PPIA. Citation Format: Li Li, Shijun Yu, Jingde Chen, Ming Quan, Yong Gao, Yandong Li. miR-15a & miR-20b enhance sorafenib sensitivity of hepatocellular carcinoma through repressing CDC37L1 and consequent PPIA downregulation [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 5347.