Interleukin-6 (IL-6) does not change the expression of Bcl-2 protein in the prevention of cisplatin-induced apoptosis in ovarian cancer cell lines.

OBJECTIVE: To study whether interleukin-6 (IL-6) changes the expression of the anti-apoptic Bcl-2 protein in the prevention of cis-diaminedichloroplatinum (II) (CDDP)-induced apoptosis of human ovarian cancer cells.
METHODS: Comparative studies were performed on 3 ovarian cancer cell lines after 48 hours of exposure to 0.5-50 ng/ml IL-6, 2 micrograms/ml anti-IL-6 monoclonal antibody (anti-IL-6 mAb), 10 microM CDDP, 10 microM CDDP + 0.5-50 ng/ml IL-6, and 10 microM CDDP + 2 micrograms/ml anti-IL-6 mAb. Apoptosis was measured morphologically and by a DNA fragmentation assay. Bcl-2 protein levels were measured by an ELISA.
RESULTS: An increase in apoptosis was observed for each cell line after 48 hours of exposure to 10 microM CDDP. Although high doses of IL-6 decreased the percentage of apoptotic cells, this cytokine did not change the expression of the Bcl-2 protein.
CONCLUSION: CDDP-induced apoptosis was negatively controlled by IL-6. However, the anti-apoptic Bcl-2 protein level was not changed by IL-6 in the process of apoptosis in the ovarian cancer cell lines.