title: Beta1 integrin adhesion enhances IL-6-mediated STAT3 signaling in myeloma cells: implications for microenvironment influence on tumor survival and proliferation.
abstract: The bone marrow microenvironmental components interleukin (IL)-6 and fibronectin (FN) individually influence the proliferation and survival of multiple myeloma (MM) cells; however, in vivo, these effectors most likely work together. We examined signaling events, cell cycle progression, and levels of drug response in MM cells either adhered to FN via beta1 integrins, stimulated with IL-6, or treated with the two combined. Although G(1)-S cell cycle arrest associated with FN adhesion was overcome when IL-6 was added, the cell adhesion-mediated drug resistance (CAM-DR) was maintained in the presence of IL-6. Concomitant exposure of MM cells to IL-6 and FN adhesion revealed a dramatic increase in signal transducers and activators of transcription 3 (STAT3) phosphorylation, nuclear translocation, and DNA binding, compared with either IL-6 or FN adhesion alone in four MM cell lines. Importantly, this increase in STAT3 activation correlated with a novel association between STAT3 and gp130 in cells adhered to FN before stimulation with IL-6, relative to nonadherent cells. Taken together, these results suggest a mechanism by which collaborative signaling by beta1 integrin and gp130 confers an increased survival advantage to MM cells.
authors.affiliation: Experimental Therapeutics and Oncologic Sciences Program, H Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, USA.
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Shain
authors.forename: Danielle N
authors.initials: DN
authors.lastname: Yarde
authors.forename: Mark B
authors.initials: MB
authors.lastname: Meads
authors.forename: Mei
authors.initials: M
authors.lastname: Huang
authors.forename: Richard
authors.initials: R
authors.lastname: Jove
authors.forename: Lori A
authors.initials: LA
authors.lastname: Hazlehurst
authors.forename: William S
authors.initials: WS
authors.lastname: Dalton
mesh_terms: D002448:Cell Adhesion / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D050822:Cytokine Receptor gp130 / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism* / Q000494:pharmacology; D009101:Multiple Myeloma / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D004273:DNA, Neoplasm; D005353:Fibronectins; D019012:Integrin beta1; D015850:Interleukin-6; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050822:Cytokine Receptor gp130