213 HEPATOCELLULAR CARCINOMA PROGRESSION IS ACCELERATED BY CANCER-ASSOCIATED FIBROBLASTS STIMULATED BY TUMOR PRODUCTION OF LYSOPHOSPHATIDIC ACID

Abstract

Aim of the study: The purpose of the present work was to examine the intracellular pathway activated by SDF-1 in HuCCt cells and whether SDF-1 could act as a growth factor and/or a survival factor for HuCCt cells. Materials and Methods: HuCCt cells and primary hHSC were employed. Intracellular signaling and apoptotic pathways were investigated by Western blot analysis. Differences in the activation of different signaling proteins compared to control conditions were detected by densitometric analysis. Growth of HuCCt cells was investigated by cell count. Results: Following stimulation of HuCCt with SDF-1, the phosphorylation of Akt, Erk and JUN increased compared to control after 5 minutes and decreased at later time points. Phosphorylation of Akt and Erk was inhibited by AMD3100, a specific inhibitor of CXCR4. HSC conditioned medium (CM) induced a 30% increase of HuCCt growth compared to control, whereas stimulation with SDF-1 was without any effect. The antiapoptotic effect of SDF-1 was evaluated by measurement of cleaved-PARP and expression of BclXl in presence of an apoptotic stimulus, i.e. Arsenic trioxide (AT). AT induced apoptosis was inhibited by the coincubation of SDF-1. Conclusions: SDF-1, secreted by HSC, induces Erk, Akt and JUN phosphorylation at different time points and this coincides with a modest survival effect on HuCCt cells.