M Etrillard | PubMed Health

PubMed2001

Interferon alpha extends the survival of human myeloma cells through an upregulation of the Mcl-1 anti-apoptotic molecule.

We have recently reported that Mcl-1, an anti-apoptotic member of the Bcl-2 family, is upregulated by interleukin (IL)-6 in human myeloma cells through the janus kinase/signal transducers and activators of transduction (JAK/STAT) pathway. In the current study, we have explored the effects of interferon (IFN)-alpha, a cytokine which has been shown to increase myeloma cell survival. Our results demonstrate that IFN-alpha potently upregulates Mcl-1 on both myeloma cell lines and purified native myeloma cells. Of note, this upregulation is not due to an induction of an IL-6 autocrine loop. Furthermore, we showed that IL-6 and IFN-alpha had no additive effect on Mcl-1 upregulation, suggesting that both cytokines act through a common mechanism. Finally, the analysis of signalling transduction pathways strongly suggests that Mcl-1 upregulation induced by IFN-alpha depends on STAT3 activation. Altogether, our data show that IFN-alpha has an IL-6-like effect on human myeloma cells and suggest that it could be deleterious in some patients.

Apoptosis↗

PubMed1994

A highly sensitive quantitative bioassay for human interleukin-11.

Human interleukin-11 (IL-11) is a cytokine with a broad spectrum of activity, similar to interleukin-6 (IL-6). However, its role in human disease is poorly understood, partly because of a lack of sensitive bioassays. A subclone (B9-11) obtained from the B9 hybridoma (which responds poorly to human IL-11) enabled us to develop a highly sensitive bioassay for human IL-11. B9-11 cells responded only to human IL-11 and IL-6 and not to other human cytokines using the same gp130 transducer chain (ciliary neurotrophic factor, leukemia inhibitory factor and oncostatin M) or to other human interleukins (interleukin-1 to interleukin-13), human hematopoietic cytokines (granulocyte colony stimulating factor, granulocyte-macrophage colony stimulating factor, colony stimulating factor-1) and various other human cytokines (interferon-alpha, tumor necrosis factor-alpha, tumor necrosis factor-beta, fibroblast growth factor and nerve growth factor). In addition, these cytokines did not interfere with the IL-11 response of B9-11 cells. IL-11-induced proliferation of B9-11 cells was unaffected by anti-murine IL-6 receptor mAb but inhibited by anti-gp130 mAb. Half-maximal proliferation of B9-11 cells was obtained with 30 pg/ml of recombinant IL-11, a concentration 300-fold lower than IL-11 concentrations known to be active on human cells. Finally, culturing of B9-11 cells with an anti-IL-6 mAb enabled us to measure the natural IL-11 produced by various cell lines. Thus, B9-11 cells should be useful for studies of IL-11 involvement in various human diseases as well as for a better understanding of the mechanisms of action of this cytokine.

Animals↗