Abstract 5381: p62/IMP2 promotes hepatocellular carcinoma (HCC) progression.

Abstract

Abstract Autoantibodies to autologous cellular antigens in cancer patients have been considered as reporters identifying antigenic changes in cellular factors involved in the transformation process. We have made use of such autoantibodies from hepatocellular carcinoma patients to immunoscreen a cDNA expression library and have identified a cytoplasmic RNA-binding protein p62. Autoantibodies to p62 have been detected in up to 21% of a cohort of hepatocellular carcinoma (HCC) patients. Further study has demonstrated that p62 is a member of insulin-like growth factor 2 mRNA binding protein family (IMPs), which is an isoform of IMP2. The three members of the IMP family (IMP1, 2 and 3) have been found to regulate translation of insulin-like growth factor 2 (IGF2) mRNA in a post-transcriptional manner. Since several studies have suggested that IMP1 and IMP3 play important roles in cancer progression, whether p62/IMP2 can also play a role in cancer formation remains to be investigated. In this study, we intend to interrogate the role of p62/IMP2 in HCC formation. We found that the expression of p62/IMP2 (57.5%) is significantly higher in HCC specimen than that in normal liver tissue (15.4%) by immunohistochemistry study. Furthermore, p62/IMP2 is detected to be overexpressed in several liver cancer cell lines. Depletion of p62/IMP2 via lentivirus-mediated knockdown in SNU449 liver cancer cell line decreased the cell proliferation. On the contrary, the ectopic overexpression of p62/IMP2 increased cell proliferation. Our data suggested that p62/IMP2 is overexpressed in liver cancer and is functionally correlated with cancer cell growth. Citation Format: Ningjing Lei, Bo Peng, Yang Li, Yurong Chai, Jianying Zhang. p62/IMP2 promotes hepatocellular carcinoma (HCC) progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5381. doi:10.1158/1538-7445.AM2013-5381