title: Modulation of Janus kinase 2 by p53 in ovarian cancer cells.
abstract: The constitutive activation of the Janus kinase 2 (JAK2) and mutation of the p53 tumor suppressor are both detected in human cancer. We examined the potential regulation of JAK2 phosphorylation by wild-type (wt) p53 in human ovarian cancer cell lines, Caov-3 and MDAH2774, which harbor mutant form of p53 tumor suppressor gene and high levels of phosphorylated JAK2. The wt p53 gene was re-introduced into the cells using an adenovirus vector. In addition to wt p53, mutant p53 22/23, mutant p53-175, and NCV (negative control virus) were introduced into the cells in the control groups. Expression of wt p53, but not that of p53-175 mutant, diminished JAK2 tyrosine phosphorylation in MDAH2774 and Caov-3 cell lines. Expression of wt p53 or p53 22/23 mutant did not cause a reduction in the phosphorylation of unrelated protein kinases, ERK1 and ERK2 (ERK1/2). The inhibition of JAK2 tyrosine phosphorylation can be reversed by tyrosine phosphatase inhibitor, sodium orthovanadate. Protein tyrosine phosphatase 1-B levels increased with introduction of wt p53 and may be involved in the dephosphorylation of JAK2. These findings present a possible p53-dependent cellular process of modulating JAK2 tyrosine phosphorylation in ovarian cancer cell lines.
authors.affiliation: Cellular and Molecular Biology Graduate Program, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-0936, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reid
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Jin
authors.forename: Hui
authors.initials: H
authors.lastname: Song
authors.forename: Huai-Jing
authors.initials: HJ
authors.lastname: Tang
authors.forename: R Kevin
authors.initials: RK
authors.lastname: Reynolds
authors.forename: Jiayuh
authors.initials: J
authors.lastname: Lin
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D005347:Fibroblasts; D017353:Gene Deletion; D006801:Humans; D053614:Janus Kinase 2; D020935:MAP Kinase Signaling System; D051379:Mice; D010051:Ovarian Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
chemical_list: D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D014638:Vanadates; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D054645:Protein Phosphatase 1; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; C516609:Ptpn1 protein, mouse