[Expression and function of protein kinase C-alpha and beta I isoenzymes in drug-resistant gastric cancer cells]

Abstract

Objective: To study the expression and function of PKC-alpha and beta I isoenzymes in drug-resistant cells of gastric cancer.

Methods: Two tumor cell lines were used in the study: gastric cancer SGC7901 and its drug-resistant counterpart SGC7901/VCR stepwise-selected by various concentrations of vincristine. The expression of PKC-alpha and beta I isoenzymes in SGC7901 and SGC7901/VCR was detected by immunohistochemistry, laser confocal scanning microscopy and Western blot. The effects of anti-PKC-alpha or beta I antibody on adriamycin accumulation in SGC7901/VCR cells were determined by flow cytometric analysis.

Results: SGC7901 cells exhibited positive staining of PKC-alpha. The staining of PKC-alpha in SGC7901/VCR was stronger than that in SGC7901 cells. The higher the concentrations of vincristine, the stronger staining of PKC-alpha was observed on SGC7901/VCR cells. Both SGC7901 and SGC7901/VCR cells were positive for PKC-beta I, but without difference in staining intensity. Comparing with SGC7901, SGC7901/VCR cells showed decreased adriamycin accumulation; the decrease was more marked with the increase in concentrations of vincristine for selection of cells. Increased adriamycin accumulation in SGC7901/VCR was observed when co-incubated with anti-PKC-alpha but not anti-PKC-beta I antibodies.

Conclusion: PKC-alpha may play a role in multidrug resistance of gastric cancer cells SGC7901/VCR.