[Correlation of protein kinase C activity and its subcellular distrubution with multidrug resistance in KVB200 cells].

Objective: To investigate the relationship between protein kinase C (PKC) and multidrug resistance (MDR) in cancer cell line KBV200.

Methods: MTT assay was used to evaluate the IC50 of vincristine (VCR) and adriamycin (ADR) in KB cell line and its VCR-resistant derivative KBV200 cells. PKC activities in the 2 cell lines were assayed by measuring the incorporation of (32)P from [gamma-(32)P] ATP into the peptide substrates.

Results: The IC50 values of VCR and ADR in KBV200 cells was 64.03 and 18.8 folds greater than those in KB cells. PKC activities of the membrane and cytosol fraction in KBV200 cells were increased compared with that in KB cells, with the total PKC activity 1.12-fold higher. Phorbol-12-myristate-13 -acetate increased PKC activity of the membrane fraction and IC50 values of KBV200 cells, while staurosporine worked to the opposite effects.

Conclusion: PKC may contribute to MDR mechanism in KBV200 cells.