Glutamate-ammonia Ligase and Reduction of G0 Population in PANC-1 Cells

In our previous study, we screened and isolated genes that were up-regulated after partial pancreatectomy using transcriptomic analysis and glutamate-ammonia ligase (GLUL) was selected for further study based on its effect on differentiation and proliferation. In the immunohistochemical analysis, GLUL was highly up-regulated in the acinar cells and the ductal cells in the pancreas damaged through partial pancreatectomy. Overexpression of GLUL enhanced the proliferation of PANC-1 cells and INS-1 cells. GLUL overexpression shifted the major population of PANC-1 cells from the G0/G1 phase to G2/M phase. In the double thymidine blocking analysis, similar cycle duration was observed between mock cells and GLUL-overexpressing cells while GLUL-overexpressing cells were partially resistant to thymidine blocking. In the FACS analysis of cells stained with Pyronin Y and Hoechst 33342, GLUL-overexpressing cells showed lower population of cells in the G0-quiescent phase than mock cells (5-12%). In addition, GLUL-overexpressing cells had high activation levels of AKT, ERK1/2, JNK, PCNA, c-FOS, and P70S6K in PANC-1 cells. Taken together, these results suggest that GLUL contributes to pancreatic regeneration.