Oncostatin M activates phosphatidylinositol-3-kinase in Kaposi's sarcoma cells

Raffaella Soldi, Andrea Graziani, Roberto Benelli, Dario Ghigo, Amalia Bosia, Adriana Albini, Federico Bussolino

Research output: Contribution to journalArticlepeer-review


Oncostatin M (OM) is a polypeptide cytokine that induces autocrine and paracrine effects on AIDS-Kaposi's sarcoma (KS) cells. The signalling pathways underlying this activation are largely unknown. We have found that OM binding to KS cell lines in vitro identifies a higher affinity binding site (Kd 10-20 pM) with a lower affinity (Kd 1.5 nM), high capacity binding site. The binding of OM to its receptor at the KS cell surface stimulates a rapid tyrosine phosphorylation of multiple proteins, including the p85 regulatory subunit of phosphatidylinositol-3-kinase (PI3K). In addition OM can stimulate the in vivo activation of PI3K and increases the PI3K activity in anti-phosphotyrosine and anti-src kinase family antibody directed immunoprecipitates. Genistein, an inhibitor of tyrosine kinases, inhibits the synthesis of phosphatidylinistol 3,4-biphosphate and the growth of KS cells. Finally, OM enhances tyrosine kinase activity in immune complex kinase assay performed with antibody anti-src kinase family. These data suggest that in KS cells OM can stimulate formation of tyrosine kinase co-ordinate signalling complexes, containing at least src kinase family and PI3K, which can drive the accumulation of the putative second-messengers D3-phosphorylated phosphoinositides.

Original languageEnglish
Pages (from-to)2253-2260
Number of pages8
Issue number8
Publication statusPublished - Aug 1994

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics


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