Neural Cell Adhesion Molecule Potentiates the Growth of Murine Melanoma via β-Catenin Signaling by Association with Fibroblast Growth Factor Receptor and Glycogen Synthase Kinase-3β

Abstract

The neural cell adhesion molecule (NCAM) was recently shown to be involved in the progression of various tumors with diverse effects. We previously demonstrated that NCAM potentiates the cellular invasion and metastasis of melanoma. Here we further report that the growth of melanoma is obviously retarded when the expression of NCAM is silenced. We found that the proliferation of murine B16F0 melanoma cells, their colony formation on soft agar, and growth of transplanted melanoma in vivo are clearly inhibited by the introduction of NCAM siRNA. Interestingly, change of NCAM expression level is shown to regulate the activity of Wnt signaling molecule, ␤-catenin, markedly. This novel machinery requires the function of FGF receptor and glycogen synthase kinase-3␤ but is independent of the Wnt receptors, MAPK-Erk and PI3K/Akt pathways. In addition, NCAM is found to form a functional complex with ␤-catenin, FGF receptor, and glycogen synthase kinase-3␤. Moreover, up-regulation of NCAM140 and NCAM180 appears more potent than NCAM120 in activation of ␤-catenin, suggesting that the intracellular domain of NCAM is required for facilitating the ␤-catenin signaling. Furthermore, the melanoma cells also exhibit distinct differentiation phenotypes with the NCAM silencing. Our findings reveal a novel regulatory role of NCAM in the progression of melanoma that might serve as a new therapeutic target for the treatment of melanoma.Melanoma arises from skin neural crest-derived pigmented melanocytes and accounts for around 80% of mortality of skin cancer (1) with less than 5% of a 5-year survival rate (2). The rapid growth of melanoma cells by overriding senescence and activation of pro-proliferating signal transduction were shown to play a key role in the development of melanoma into metastatic stage (3). Even though many cell growth promoting factors have been identified to be involved in the progression of melanoma and targeted for therapeutic intervention, the treatment efficacy of advanced melanoma with vertical growth and metastasis has not been significantly improved over the past few decades (1). Hence, further study to elucidate the molecular mechanisms underlying the proliferation of melanoma cells is required for the finding of novel potential intervention targets to improve the treatment of melanoma.It has been demonstrated that the adhesion molecules that mediate intercellular and cell-matrix interactions extensively participate in the progression of melanoma (4, 5) by altering the adhesion status and signal transduction of the cells. Neural cell adhesion molecule (NCAM), 2 a member of the immunoglobulin superfamily, has been well characterized in cell proliferation, differentiation, migration, neurite outgrowth, and synaptic plasticity in the nervous system (6 -9). However, recent studies have also revealed that the expression of NCAM drastically fluctuates in many tumors and affects tumor progression and prognosis (10). In small cell lung cancer (11) and the majority of multiple myelomas (12), the up-regulation of NC...

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“…NCAM1 stimulates migration and invasion of epithelial ovarian carcinoma cells and melanoma cells and promotes metastatic dissemination in mice. This promalignant function of NCAM1 is mediated by its interaction with fibroblast growth factor receptor (38,48). FOXG1 acts as an oncoprotein inhibiting TGF-b-mediated antiproliferative responses in medulloblastomas and ovarian cancer cells through suppressing p21 WAF1/CIP1 transcription (37,49).…”

Inhibition of Neurosphere Formation in Neural Stem/Progenitor Cells by Acrylamide

“…We estimated that the 0.5 mg/kg body weight is quite comparable to the 0.5 mM concentration that was used in the cell culture. The ablation of the expression of NCAM resulted in the disruption of the tumor tissue architecture (40), and its downregulation is observed in the development of colon cancer, myeloma, and neuroblastoma (3,14,25). NCAM is also known to mediate several neuronal functions in the central nervous system (20).…”

“…The Wnt/b-catenin pathway causes GSK3b inactivation through Ser 9 phosphorylation and further activates the b-catenin and downstream genes. Phosphorylated bcatenin has been shown to be phosphorylated by GSK3b at serine 33 and 37, which leads to its degradation (40).…”

“…Downregulation of NCAM of murine melanoma cells and GBM-SCs resulted in sphere formation inhibition by NCAM siRNA or chemical treatment, which was related to FGFR-associated signaling pathways (4,30). Cross talk between adhesion molecules and RTK has important functional implications, and its deregulation can play a pathogenic role in a number of diseases, including cancer and neurological disorders (40).…”

“…Neural cell adhesion molecule (NCAM) is a member of the immunoglobulin-like superfamily, which mediates intercellular and cell-matrix interactions and activates FGFRassociated signaling pathways, such as extracellular signalregulated kinase (ERK), protein kinase C, cAMP-dependent protein kinase, phosphatidylinositide 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT), Fyn oncogene, and focal adhesion kinase (30,40). Downregulation of NCAM of murine melanoma cells and GBM-SCs resulted in sphere formation inhibition by NCAM siRNA or chemical treatment, which was related to FGFR-associated signaling pathways (4,30).…”