Src transduces signaling via growth hormone (GH)-activated GH receptor (GHR) tyrosine-phosphorylating GHR and STAT5 in human leukemia cells

• Published in: Leukemia research 2006-11, Vol.30 (11), p.1391-1398
• Main Authors: Manabe, Noriko, Kubota, Yoshitsugu, Kitanaka, Akira, Ohnishi, Hiroaki, Taminato, Tomohiko, Tanaka, Terukazu
• Format: Article
• Language: English
• Subjects: Cell Line, Tumor; Growth hormone; Growth Hormone - antagonists & inhibitors; Growth Hormone - pharmacology; Growth hormone receptor; Humans; Jak2; Leukemia - drug therapy; Leukemia - metabolism; Oligonucleotides, Antisense - pharmacology; Phosphorylation; Protein Kinase Inhibitors - pharmacology; Receptors, Somatotropin - drug effects; Receptors, Somatotropin - metabolism; Signal Transduction - drug effects; Src; src-Family Kinases - drug effects; src-Family Kinases - metabolism; STAT5; STAT5 Transcription Factor - drug effects; STAT5 Transcription Factor - metabolism; Structure-Activity Relationship; Tyrosine - drug effects; Tyrosine - metabolism; Tyrosine phosphorylation
• ISSN: 0145-2126; 1873-5835
• DOI: 10.1016/j.leukres.2006.03.024

Most human leukemia cells are shown to express growth hormone receptor (GHR) and some of them proliferate in response to GH. We demonstrate that Src contributes to GHR-mediated signal transduction via STAT5 activation in F-36P human leukemia cells stimulated with GH. The tyrosine phosphorylation levels of GHR and STAT5 induced by GH decreased in the presence of PP2 Src kinase inhibitor. When GHR and wild-type Src were co-expressed in COS7 cells, GHR was markedly tyrosine phosphorylated as well as when Jak2 was co-expressed with GHR, but not when kinase-inactive Src co-expressed. The treatment of F-36P cells with the antisense src oligonucleotides, which selectively decreased the Src expression, reduced the rhGH-induced tyrosine phosphorylation of the STAT5 activation sites.