354 - Prevalence and Stratification of NAFLD/NASH in a UK and US Cohort Using Non-Invasive Multiparametric MRI

characterized by the loss of or failure to achieve polarity.This is of particular interest to us because MAL2 is thought to be involved with the establishment and/or maintenance of a polarized phenotype.Therefore, it is important to consider how loss or dysregulation of polarized protein trafficking contributes to malignant transformation.To identify possible mechanisms linking MAL2 up-regulation to malignancy, we overexpressed wild-type MAL2 in hepatoma-derived Clone9 cells that lack endogenous MAL2.Our results showed that MAL2 overexpression induced actin-based protrusions formation with MAL2 localized to their tips.A closer look at the rat MAL2 cytosolic N-terminus protein sequence revealed two domains (VPPPP and FPAP) that resemble the F/L/W/YPPPP recognition sites for EVH1 (enabled, VASP, homology1) motifs present in the actin-associated Ena/VASP proteins, suggesting a possible involvement of MAL2 in actin dynamics.We generated recombinant adenoviruses with either or both of these proline-rich motifs mutated to alanines.We determined that Clone9 cells expressing the FPAP or double mutant construct, displayed fewer protrusions formation, suggesting that MAL2 promotes changes in the cell membrane morphology via its FPAP but not its VPPPP domain.To our surprise, MAL2 did not induce increased cell proliferation, migration and/or invasion when overexpressed in Clone9 cells.Interestingly, human-derived hepatocellular carcinoma Hep3B cells with endogenous MAL2 also displayed abundant protrusions formation, and MAL2 knockdown reversed these phenotypes.Similarly, we observed decreased migration in Hep3B cells with endogenous MAL2 using the CytoSMART live-cell imaging platform, suggesting that high MAL2 expression in liver-derived cancer cells may be potentially favorable, and its role in malignancy may be cell specific.Because MAL2 plays an essential role in transcytosis and constitutive secretion, we are still investigating whether MAL2 regulates vesicle delivery to the migrating front and/ or secretion in cancer cell lines.