Abstract 2027: P62/IMP2 promotes metastasis in hepatocellular carcinoma (HCC) by regulating EMT in different signaling pathway

Abstract

Abstract Insulin- like growth factor 2 mRNA binding proteins (IMPs) Family contains three members: IMP1, IMP2 and IMP3. IMPs are oncofetal proteins, expressed during embryogenesis and lost in most tissues in adults. Overexpressed IMPs have been reported in various types of cancers. They share similar protein structure in mammals and have similar functions: to bind specific mRNAs, stabilize and extend their half-life. IMP2 was first reported as a tumor-associated antigen in HCC. However, only a few research was done on what a role of p62/IMP2 plays on HCC progression. Previous studies show that IMP2 is overexpressed in HCC tissues and in several human HCC cell lines. Western blotting was performed for different HCC cells has a relatively low expression in SNU449 and higher expression in HepG2 and Hep3b. Stable IMP2 overexpression SNU449 cell line was made by IMP2 cDNA plasmid transfection; stable IMP2 knockout Hep3b and HepG2 cell lines was made by IMP2 Crispr-Cas9 KO plasmid transfection. Wound healing assay has shown that overexpression of p62/IMP2 can significantly enhance cell migration ability in SNU449 cells. On the contrary, the depletion of p62/IMP2 can reduce the migration ability in HepG2 and Hep3b cells (p<0.05). Furthermore, we analyzed HCC gene expression data from TCGA. Median count of IMP2 was used to separate HCC expression data into high and low IMP2 expression group to conduct differential gene expression analysis. Gene Ontology over-representation analysis shows differentially expressed genes (adjusted p<0.05) mainly enriched in membrane part and plasma membrane. The expression of several genes involved in EMT regulation such as CTNNB1, SMAD2, SNAI2, AKT2 shows significant difference (adjust p<0.05). Western blotting assay was performed to show whether IMP2 is involved in EMT regulation. Wnt/beta-catenin pathway and TGF-beta/SMAD pathway were both activated and further upregulated SNAIL, which is an E-cadherin inhibitor. Western blotting results showed that E-cadherin was inhibited in IMP2 overexpressed SNU449 cells, which is supportive to our hypothesis. Citation Format: Mengtao Xing, Jianxiang Shi, Jitian Li, Beibei Chen, Giulio Francia, Jianying Zhang. P62/IMP2 promotes metastasis in hepatocellular carcinoma (HCC) by regulating EMT in different signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2027.