Gp130 and ras mediated signaling in human plasma cell line INA-6: a cytokine-regulated tumor model for plasmacytoma.

Introduction: Cytokines of the gp130-family, particularly interleukin(IL)-6, play a crucial role in the propagation of malignant plasma cells.

Materials And Methods: The role of IL-6 and other gp130-cytokines was studied in the human plasma cell line INA-6 in vitro and in INA-6 xenografts. The proliferative response to gp130-cytokines was evaluated and activated components of gp130-signaling pathways were identified by Western blotting and DNA binding studies.

Rab11b is essential for recycling of transferrin to the plasma membrane.

Members of the Rab family of small GTPases play important roles in membrane trafficking along the exocytic and endocytic pathways. The Rab11 subfamily consists of two highly conserved members, Rab11a and Rab11b. Rab11a has been localized both to the pericentriolar recycling endosome and to the trans-Golgi network and functions in recycling of transferrin.

Interleukin-6 activates signal transducer and activator of transcription and mitogen-activated protein kinase signal transduction pathways and induces de novo protein synthesis in human neuronal cells.

Interleukin-6 (IL-6) is involved in the pathophysiology of various diseases of the CNS. Because the molecular mechanism of action of this cytokine in human neurons is not well understood, we were interested in characterizing and defining a model system for IL-6-induced activation of signal transduction cascades, transcriptional activation, and protein synthesis in human neuronal cells. We show that IL-6 leads to transcriptional activation of signal transducer and activator of transcription 3 (STAT3) in human SH-SY5Y neuroblastoma cells.