Neuroblastoma-derived secretory protein is a novel secreted factor overexpressed in neuroblastoma

作者：Vasudevan Sanjeev A; Shang Xiaoyi; Chang Shirong; Ge Ningling; Diaz Miron Jose L; Russell Heidi V; Hicks M John; Ludwig Andrew D; Wesson Catherine L; Burlingame Susan M; Kim Eugene S; Khan Javed; Yang Jianhua^*; Nuchtern Jed G

来源：Molecular Cancer Therapeutics, 2009, 8(8): 2478-2489.

DOI：10.1158/1535-7163.MCT-08-1132

Secreted proteins such as growth factors, cytokines, and chemokines play important roles in tumor development. Through expression microarray and bioinformatic analysis, we discovered a novel secreted protein, neuroblastoma-derived secretory protein (NDSP). The NDSP gene is found on chromosome 1q25.2 and encodes a 167 amino acid protein with a putative signal peptide. Using real-time PCR and immunoblotting, we find that NDSP is specifically overexpressed in neuroblastoma at much higher levels than other adult and pediatric malignancies and normal tissues. NDSP is an 18-kDa protein that can be secreted by NDSP-transfected HEK-293T cells, as well as, neuroblastoma cell lines endogenously expressing NDSP. Inhibiting NDSP expression in neuroblastoma cell lines with retrovirally transduced NDSP small hairpin interfering RNA, sh-NDSP, results in decreased cellular proliferation and colony formation. We also find inhibited extracellular signal-regulated kinase (ERK) 1/2 phosphorylation in the sh-NDSP cell line. Treating the parental cell line with MAP/ERK kinase 1/2 inhibitors, which diminish ERK 1/2 phosphorylation, results in decreased cell proliferation. Culturing these transduced cells with recombinant NDSP, reintroducing NDSP overexpression in the knockdown cell line, or inducing Ras oncogene overexpression for constitutive ERK 1/2 activation results in a reversal of the growth-inhibited phenotype and proliferation rates similar to the control cells. In addition, reintroduction of NDSP overexpression in the sh-NDSP cell line results in ERK 1/2 phosphorylation similar to control. We conclude that NDSP is specifically overexpressed in neuroblastoma and actively secreted from tumor cells. Furthermore, NDSP serves as a growth factor for neuroblastoma tumor cells through activation of the ERK-mediated proliferation pathway. [Mol Cancer Ther 2009;8(8):2478-89]

• 出版日期2009-8
• 单位复旦大学