Group II phospholipase A2 in invasive gastric cancer cell line is induced by interleukin 6.

To investigate the role of group II phospholipase A2(PLA2) in cancer, we examined the expression and secretion of group II PLA2 in response to the stimulation of interleukin 6(IL-6) in human gastric cancer cells in vitro. Group II PLA2 determined by a specific radioimmunoassay was constitutively produced in culture supernatant of KATO III (signet ring cell carcinoma) and MKN28 (well differentiated adenocarcinoma). This production in KATO III significantly increased with a treatment of IL-6, whereas that in MKN28 remained at a same level. Moreover, the quantitation by reverse transcription-polymerase chain reaction(RT-PCR) demonstrated the IL-6 inducible overexpression of group II PLA2 mRNA in KATO III. This transcription was mediated by NF-IL6, the same as in hepatocytes. These results suggest two possible mechanisms of group II PLA2 production by cancer cells in vivo, that is, cytokine-induced production and constitutive production.