Association of sorcin with drug resistance in L1210 cells.

L1210 sublines independently selected for resistance to teniposide (VM-26), etoposide (VP-16), doxorubicin (DOX), dactinomycin (DACT), or vincristine (VCR) express an anionic, 22-kDa protein that is not observed in extracts of parental L1210 cells. Antibody raised against sorcin, an acidic calcium-binding protein overproduced in many other cells resistant to these agents, cross-reacts with the 22-kDa polypeptide. The levels of the 22-kDa protein (sorcin) increase with the relative levels of drug resistance of the L1210 sublines. The appearance of sorcin in these various sublines further supports the notion that the overproduction of this protein is related to the general phenomenon of multidrug resistance rather than to specific drug resistance and that selection for resistance to teniposide produces L1210 sublines with multidrug resistance.