Characterization of signaling cascades triggered by human interleukin-6 versus Kaposi's sarcoma-associated herpes virus-encoded viral interleukin 6.
Kaposi's sarcoma-associated herpes virus (KSHV) is associated with Kaposi's sarcoma, multicentric Castleman's disease, and body cavity-based lymphomas, settings in which human interleukin-6 (hIL-6) acts as a growth factor. The KSHV open reading frame K2 encodes for viral IL-6 (vIL-6), a protein with 25% amino acid identity to hIL-6, which can promote the growth of hIL-6-dependent cell lines. In the present study, we characterized biological sequelae and signaling cascades triggered by hIL-6 versus vIL-6 in the hIL-6-dependent MH60 and B9 cell lines. Both hIL-6 and vIL-6 induced significant increases (P < 0.01) in DNA synthesis in these cell lines in a dose-dependent fashion. Neutralizing anti-hIL-6 antibody (Ab) inhibited DNA synthesis triggered by hIL-6, without similarly affecting proliferation in response to vIL-6. On the other hand, antimouse IL-6 receptor (mIL-6R) Ab blocked response to vIL-6, but not that to hIL-6. Both hIL-6 and vIL-6 activated gp130, Janus kinase 1, signal transducers and activators of transcription-3, and mitogen-activated protein kinase in both MH60 and B9 cells. Proliferation of these cell lines in response to both hIL-6 and vIL-6 was blocked by PD98059, an inhibitor of MEK1 activation. These data suggest that MEK1 activation mediates the proliferative response to both cytokines. Finally, both hIL-6 and vIL-6 also maintained viability of serum-starved MH60 and B9 cells and blocked dexamethasone-induced apoptosis of MM.1S human myeloma cells. Further characterization of the signaling cascades mediating the growth and antiapoptotic effects of vIL-6 versus hIL-6 may help identify their unique roles in disease pathogenesis in Kaposi's sarcoma and other KSHV-associated neoplasms.
Hideshima
T
T
Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Chauhan
D
D
Teoh
G
G
Raje
N
N
Treon
S P
SP
Tai
Y T
YT
Shima
Y
Y
Anderson
K C
KC
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015703:Antigens, CD / Q000187:drug effects / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D019288:Herpesvirus 8, Human / Q000235:genetics; D006801:Humans; D006825:Hybridomas; D015850:Interleukin-6 / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D048369:MAP Kinase Kinase 1; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009500:Neutralization Tests; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D019947:Receptors, Interleukin-6 / Q000276:immunology; D011994:Recombinant Proteins / Q000494:pharmacology; D050794:STAT1 Transcription Factor; D050795:STAT2 Transcription Factor; D015398:Signal Transduction / Q000187:drug effects*; D015534:Trans-Activators / Q000187:drug effects / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000494:pharmacology*
D000906:Antibodies; D015703:Antigens, CD; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; C494199:IL6ST protein, human; C494200:Il6st protein, mouse; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050795:STAT2 Transcription Factor; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D014764:Viral Proteins; D050822:Cytokine Receptor gp130; D014443:Tyrosine; D003907:Dexamethasone; D011505:Protein-Tyrosine Kinases; C507904:JAK1 protein, human; C507924:JAK2 protein, human; C507905:Jak1 protein, mouse; C507926:Jak2 protein, mouse; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one