title: Inhibition of JAK3 induces apoptosis and decreases anaplastic lymphoma kinase activity in anaplastic large cell lymphoma.
abstract: Signal transducer and activator of transcription 3 (STAT3), normally activated by Janus kinase (JAK) in response to cytokine stimulation, has been shown to have oncogenic potential. In addition to JAK, recent data suggest that STAT3 can also be activated by other proteins such as the aberrant fusion protein, NPM-ALK, which is expressed in a subset of systemic anaplastic large cell lymphoma (ALCL). In this study, we investigated the possible role of JAK in activating STAT3 in ALCL using two ALK-positive ALCL cell lines, Karpas 299 and SU-DHL-1. At the steady state, JAK3 showed detectable tyrosine phosphorylation by immunoprecipitation. Treatment with AG490, a JAK inhibitor, decreased but did not completely abrogate tyrosine phosphorylation of JAK3 and STAT3 in a concentration-dependent manner. Similar results were obtained using two other inhibitors of JAK3, WHI-P131 and WHI-P154. These biochemical changes were associated with apoptosis in both cell lines that was coupled with activation of caspase 3 and decreased bcl-xL and bcl-2. Cell cycle analysis revealed a decrease in the S phase, which may be attributed to cyclin D3 downregulation and p21(waf1) upregulation. Importantly, the tyrosine kinase activity of NPM-ALK, as assessed by an in vitro assay, decreased with increasing concentrations of AG490. Our findings highlight the importance of JAK3 in activating STAT3 in ALCL, and that NPM-ALK-mediated activation of STAT3 is influenced by the functional status of JAK3.
authors.affiliation: Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Hesham M
authors.initials: HM
authors.lastname: Amin
authors.forename: L Jeffrey
authors.initials: LJ
authors.lastname: Medeiros
authors.forename: Yupo
authors.initials: Y
authors.lastname: Ma
authors.forename: Marianna
authors.initials: M
authors.lastname: Feretzaki
authors.forename: Pamela
authors.initials: P
authors.lastname: Das
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Leventaki
authors.forename: George Z
authors.initials: GZ
authors.lastname: Rassidakis
authors.forename: Sean L
authors.initials: SL
authors.lastname: O'Connor
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: McDonnell
authors.forename: Raymond
authors.initials: R
authors.lastname: Lai
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D053616:Janus Kinase 3; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy / Q000201:enzymology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; C507933:JAK3 protein, human; D053616:Janus Kinase 3; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases