Point Mutation at Single Tyrosine Residue of Novel Oncogene NOK Abrogates Tumorigenesis in Nude Mice

Abstract

Receptor protein-tyrosine kinases (RPTKs) are tightly regulated during normal cellular processes including cell growth, differentiation, and metabolism. Recently, a RPTK-like molecule named novel oncogene with kinase-domain (NOK) has been cloned and characterized. Overexpression of NOK caused severe cellular transformation as well as tumorigenesis and metastasis in nude mice. In the current study, we generated two tyrosine!phenylalanine (Y!F) point mutations (Y327F and Y356F) within the endodomain of NOK that are well conserved in many RPTK subfamilies and are the potential tyrosine phosphorylation sites important for major intracellular signaling. Using BaF3 cells stably expressing the ectodomain of mouse erythropoietin receptor, and the transmembrane and endodomain of NOK (BaF3-E/N), we were able to show that point mutations at either Y327 or Y356 dramatically blocked cellular transformation by NOK as examined by colony formation and cellular DNA synthesis. In addition, tumorigenesis induced by BaF3-E/N was completely abrogated upon the introduction of either single mutation. Importantly, signaling studies revealed that the activation of extracellular signal-regulated kinase was inhibited by Y356F and was significantly reduced by Y327F. Both mutations significantly impaired Akt phosphorylation. Interestingly, both mutations did not affect the kinase activity of NOK. Moreover, apoptotic analysis revealed that both mutations accelerated cell death by activating caspase-3-mediated pathways. Thus, our study shows that these potential tyrosine phosphorylation sites may play critical roles in NOKmediated tumorigenesis both in vitro and in vivo. (Cancer Res 2005; 65(23): 10838-46)

Diagnostic Relevance of Overexpressed Serine Threonine Tyrosine Kinase/Novel Oncogene with Kinase Domain (STYK1/NOK) mRNA in Colorectal Cancer

“…It is reported to be an important factor in tumorigenesis and metastasis in nude mice, and it is and it is proved to lead growth factor-independent cell proliferation among murine, bone-marrow-derived, lymphatic BaF3 cells and surface-adhesion-independent growth and colony forming in NIH3T3 and BaF3 cells (Chen et al, 2005, Li et al, 2009, Ding et al, 2012. Furthermore, NOK/STYK1 oncogenic potential in breast, lung, prostate and ovarian cancers has been reported (Amachika et al, 2007, Kimbro et al, 2008, Jackson et al, 2009.…”

Diagnostic relevance of overexpressed mRNA of novel oncogene with kinase-domain (NOK) in lung cancers

“…Overexpression of the NOK gene resulted in growth factorindependent cell proliferation in BaF3 cells and also surface adhesion-independent growth and colony formation in both NIH3T3 and BaF3 cells [14]. Further, the overexpression of NOK in BaF3 cells induced tumorigenesis and metastasis in nude mice [14,15]. These observations indicate that NOK is a critical molecule promoting cell proliferation and suggest that NOK expression could be up-regulated in cancer cells.…”

Altered LKB1/CREB-regulated transcription co-activator (CRTC) signaling axis promotes esophageal cancer cell migration and invasion

“…For instance, one of genes upregulated by CRTC1 in our gene expression profiling analysis is STYK1/NOK. This gene encodes a serine/threonine/tyrosine kinase 1, and its overexpression in pre-B cells, Baf3 was found to cause growth factor-independent proliferation and colony formation in vitro and induced tumorigenesis and metastasis in nude mice (Liu et al, 2004;Chen et al, 2005). Also, it is unclear whether there is a role of STYK1 in regulating SIKs or AMPKs that might affect CRTC phosphorylation and function.…”