title: Signal pathways in up-regulation of chemokines by tyrosine kinase MER/NYK in prostate cancer cells.
abstract: The AXL/UFO family of tyrosine kinases is characterized by a common N-CAM (neural adhesion molecule)-related extracellular domain and a common ligand, GAS6 (growth arrest-specific protein 6). Family members are prone to transcriptional regulation and carry out diverse functions including the regulation of cell adhesion, migration, phagocytosis, and survival. In this report, we describe a new role of MER/N-CAM-related kinase (NYK), a member of the AXL family of kinases, in the up-regulation of chemokines in prostate cancer cells. We show that NYK has elevated expression in a subset of tumor specimens and prostate cancer cell lines. Activation of NYK in the prostate cancer cell line DU145 does not cause a mitogenic effect; instead, it causes a differentiation phenotype. Microarray analysis revealed that NYK is a strong inducer of endocrine factors including interleukin (IL)-8 and several other angiogenic CXC chemokines as well as bone morphogenic factors. The dramatic increase of IL-8 expression is seen at both transcriptional and posttranscriptional levels. The downstream signals engaged by NYK were characterized, and those responsible for the up-regulation of IL-8 transcription were defined. In contrast to IL-1alpha, NYK-induced up-regulation of IL-8 in DU145 depends on the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase/Jun/Fos pathway, but not phosphoinositide 3'-kinase/nuclear factor-kappaB. These data define a new function of the AXL family of kinases and suggest a potential role of NYK in prostate cancer progression.
authors.affiliation: University of California at Davis, University of California Davis Cancer Center, Sacramento, California, USA.
authors.forename: Yi-Mi
authors.initials: YM
authors.lastname: Wu
authors.forename: Dan R
authors.initials: DR
authors.lastname: Robinson
authors.forename: Hsing-Jien
authors.initials: HJ
authors.lastname: Kung
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000378:metabolism*; D015533:Transcriptional Activation; D015854:Up-Regulation; D000076202:c-Mer Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases; D000076202:c-Mer Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6; C097072:MERTK protein, human