title: TNF α mediated IL-6 secretion is regulated by JAK/STAT pathway but not by MEK phosphorylation and AKT phosphorylation in U266 multiple myeloma cells.
abstract: IL-6 and TNF α were significantly increased in the bone marrow aspirate samples of patients with active multiple myeloma (MM) compared to those of normal controls. Furthermore, MM patients with advanced aggressive disease had significantly higher levels of IL-6 and TNF α than those with MM in plateau phase. TNF α increased interleukin-6 (IL-6) production from MM cells. However, the detailed mechanisms involved in signaling pathways by which TNF α promotes IL-6 secretion from MM cells are largely unknown. In our study, we found that TNF α treatments induce MEK and AKT phosphorylation. TNF α -stimulated IL-6 production was abolished by inhibition of JAK2 and IKK β or by small interfering RNA (siRNA) targeting TNF receptors (TNFR) but not by MEK, p38, and PI3K inhibitors. Also, TNF α increased phosphorylation of STAT3 (ser727) including c-Myc and cyclin D1. Three different types of JAK inhibitors decreased the activation of the previously mentioned pathways. In conclusion, blockage of JAK/STAT-mediated NF- κ B activation was highly effective in controlling the growth of MM cells and, consequently, an inhibitor of TNF α -mediated IL-6 secretion would be a potential new therapeutic agent for patients with multiple myeloma.
authors.affiliation: Cancer Research Institute, College of Medicine, Seoul National University, 101 Daehak-ro, Jongro-gu, Seoul 110-799, Republic of Korea.
authors.forename: Chansu
authors.initials: C
authors.lastname: Lee
authors.forename: Jeong-In
authors.initials: JI
authors.lastname: Oh
authors.forename: Juwon
authors.initials: J
authors.lastname: Park
authors.forename: Jee-Hye
authors.initials: JH
authors.lastname: Choi
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Bae
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Lee
authors.forename: Woo June
authors.initials: WJ
authors.lastname: Jung
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Lee
authors.forename: Kwang-Sung
authors.initials: KS
authors.lastname: Ahn
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000378:metabolism; D053614:Janus Kinase 2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D020930:MAP Kinase Kinase Kinases / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics* / Q000473:pathology; D051058:Oncogene Protein v-akt / Q000096:biosynthesis / Q000378:metabolism; D010766:Phosphorylation; D034741:RNA, Small Interfering; D050791:STAT Transcription Factors; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D034741:RNA, Small Interfering; D050791:STAT Transcription Factors; D014409:Tumor Necrosis Factor-alpha; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D051058:Oncogene Protein v-akt; D051550:I-kappa B Kinase; D020930:MAP Kinase Kinase Kinases