GP130 in Human Myeloma/Plasmacytoma

Abstract

Interleukin 6 (IL-6) is a potent growth factor for human myeloma/plasmacytoma cells (Kawano et al. 1988, Klein et al. 1989) The evidences that 1) myeloma cells produce IL-6 and express IL-6 receptor (IL-6R), 2) IL-6 augments the in vitro growth of myeloma cells, 3) anti-IL-6 antibody (Ab) or anti-IL-6R Ab inhibits their growth (Klein et al. 1991, Sato et al. 1993) support the autocrine or paracrine mechanism of IL-6 for myeloma cell growth. The cytoplasmic region of IL-6R is very short (Yamasaki et al. 1988) and a signal transducing molecule, gp130 was discovered (Hibi et al. 1990). Furthermore, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF) and IL-11 have been shown to share the same signal transducer, gp130 in their receptor systems (for review see Kishimoto et al. 1994). On the basis of this finding, it seems likely that these cytokines as well as IL-6 may be the growth factors for human myeloma/ plasmacytoma cells (Nishimoto et al. 1994, Zhang et al. 1994). In this report, we show the stimulatory effect of LIF and OSM and the inhibitory effect of anti-gp130 monoclonal antibody (mAb) on the growth of freshly isolated plasmacytoma cells.