Establishment of an etoposide (VP-16)-resistant subline of THP-1 human monocytic leukemia cell line.

SMJO, Y., KUMANO, N., SUZUKI, S., KOINUMARU, S., SUGAWARA, S., OIZUMI, K. and MOTOMIYA, M. Establishment of an Etoposide (VP-16)-Resistant Subline of THP-1 Human Monocytic Leukemia Cell Line. Tohoku J. Exp. Med., 1989, 157 (3), 215-219 - A VP-16-resistant subline was established from THP-1 human monocytic leukemia cells by subculturing in stepwise increasing concentrations of the drug. The resistant cells (THP-1/E) were capable of sustaining continuous growth in 1.0μg/ml VP-16. The 50% inhibition dose (IC50) was 1.4μg/ml or a 35-fold of the parent cells. A more than 18-fold IC50 was also obtained with teniposide (VM-26). However, no substantial cross-resistance was observed with 5 other antineoplastic drugs, IC50 values being limited below several times of THP-1.