Signaling pathway of ciliary neurotrophic factor in neuroblastoma cell lines

Background Ciliary neurotrophic factor (CNTF) is a member of the interleuki n-6 (IL-6) cytokine family and affects the survival and differentiation of several classes of neurons. For signal transduction, CNTF requires a recept or complex, composed of the IL-6 signal transducing molecule gp130, leukemi a inhibitory factor receptor (LIFR)-beta, and CNTFR-alpha. There are two ma jor independent pathways (Jak-STAT and Ras-MAPK) in cell signaling, and som e recent reports show interaction between these pathways. The signal of the IL-6 family is mainly transduced to the Jak-STAT pathway through gp130. Ho wever, it has not been examined in neuroblastoma in detail. Procedure and R esults, Here we examine the signaling pathway of CNTF in 11 neuroblastoma c ell lines. Northern blot analysis revealed that 3 of the 11 cell lines expr essed c-fos mRNA after CNTF stimulation. Cell lysates were immunoprecipitat ed with agarose-conjugated antiphosphotyrosine antibody and blotted with an ti-gp130, anti-Jak1, or anti-STAT3 antibody. Tyrosine phosphorylation of gp 130, Jak1, and STAT3 was observed after CNTF stimulation in these three cel l lines. Furthermore, tyrosine phosphorylation of ERK1 (one of the MAPKs) w as also observed in all of them. Conclusions. These results demonstrate tha t CNTF signaling is conserved in some of the neuroblastoma cell lines and s uggest that not only a Jak-STAT pathway but a MAPK pathway is activated by CNTF through gp130 in neuroblastoma cell lines. Med. Pediatr. Oncol. 36:118 -121, 2001. (C) 2001. Wiley-Liss. Inc.