EFFECT OF THE NITROSOUREA ANTITUMOR CHEMOTHERAPEUTICAL AGENT MCNU ON 5 HUMAN MYELOMA CELL-LINES

We investigated the effects of MCNU -3-nitrosoureido)-6-deoxy-alpha-D- glucopyranoside, a nitrosourea anti-tumor agent developed in Japan, on cell growth and differentiation in five human myeloma cell lines and compared it with relative expression levels of MDR-1 gene. Although 10 mu g/ml of MCNU inhibited cell growth in KMM-1 and KMS-5 lines, other three cell lines required 20-40 mu g/ml of MCNU to obtain similar gro wth inhibition. Accumulation up to the G2 phase of the cell cycle was observed in KMM-1 and KMS-5 lines and the cloning efficiency of KMS-5 cells was reduced by MCNU. On the other hand, expression of surface ma rkers on these lines was not altered remarkably except for increased e xpression of CD38 on KMS-5 cells. However, the effect of MCNU on these cell lines did not correlate to relative expression levels of MDR-1 g ene analyzed by RT-PCR. MCNU may inhibit the growth of myeloma cells b y the accumulation of these cells up to the G2 phase, but may not affe ct their differentiation.