ESTABLISHMENT OF A NOVEL MYELOMA CELL-LINE KPMM2 CARRYING T(3-14)(Q21-Q32), WHICH PROLIFERATES SPECIFICALLY IN RESPONSE TO INTERLEUKIN-6 THROUGH AN AUTOCRINE MECHANISM

We established a new human myeloma cell line, KPMM2, which proliferate s specifically in response to IL-6 via an autocrine mechanism. The pro liferative response of KPMM2 cells to exogenous IL-6 was significantly stimulated in a dose-dependent manner. The growth was markedly inhibi ted by an anti-IL-6 mAb and an anti-IL-6 receptor (IL-6R) mAb in a dos e-dependent manner. KPMM2 cells expressed IL-6 and IL-6R mRNA by RT-PC R. Flow cytometric analysis showed cell surface expression of IL-6R. I L-6 protein was detected in the culture supernatant by ELISA. IL-11, o ncostatin M and leukemia inhibitory factor had no effect on the prolif eration of KPMM2 cells although interferon-alpha and interferon-gamma inhibited the growth. Furthermore, KPMM2 cells bore a t(3;14)(q21;q32) translocation and this finding is of potential interest for future st udies in the light of the nuclear protein BM28 (CDCL1, for cdc-like 1) mapped on 3q21, which plays an important role in the cell cycle. In t his report, we demonstrated completely an IL-6-dependent autocrine gro wth mechanism in KPMM2 cell line. This cell line may be useful to inve stigate the pathogenesis of multiple myeloma and to evaluate the thera peutic potential of IL-6 blocking agents in vitro and in vivo.