Group VIB Phospholipase A₂ Promotes Proliferation of INS-1 Insulinoma Cells and Attenuates Lipid Peroxidation and Apoptosis Induced by Inflammatory Cytokines and Oxidant Agents

Influence of the inflammatory cytokines interleukin-1β (IL-1β) and interferon-γ (IFN-γ) on iPLA ₂γ expression by INS-1 cells. Control INS-1 cells were incubated with vehicle alone or with various concentrations of IL-1β and IFN-γ for 16 hr, and iPLA₂γ mRNA levels were then determined by quantitative PCR (panel (a)) and iPLA₂γ protein levels by Western blotting (panel (b)), as described in Experimental Procedures. In panel (c), control INS-1 cells were incubated with IL-1β (5 ng/mL) and IFN-γ (80 ng/mL) for various intervals (0, 8, 16, 24, and 48 hr), at the end of which iPLA₂γ mRNA levels were determined by quantitative PCR. In panels (a) and (c), mean values ± SEM () are displayed, and an asterisk (*) indicates a significant difference () from the condition in which the concentration (panel (a)) or time (panel (b)) parameter value was zero. The immunoblot in panel (b) is representative of four experiments.