We report that artemin, a member of the glial cell linederived neurotrophic factor family of ligands, is oncogenic for human mammary carcinoma. Artemin is expressed in numerous human mammary carcinoma cell lines. Forced expression of artemin in mammary carcinoma cells results in increased anchorage-independent growth, increased colony formation in soft agar and in three-dimensional Matrigel, and also promotes a scattered cell phenotype with enhanced migration and invasion. Moreover, forced expression of artemin increases tumor size in xenograft models and leads to highly proliferative, poorly differentiated and invasive tumors. Expression data in Oncomine indicate that high artemin expression is significantly associated with residual disease after chemotherapy, metastasis, relapse and death. Artemin protein is detectable in 65% of mammary carcinoma and its expression correlates to decreased overall survival in the cohort of patients. Depletion of endogenous artemin with small interfering RNA, or antibody inhibition of artemin, decreases the oncogenicity and invasiveness of mammary carcinoma cells. Artemin is therefore oncogenic for human mammary carcinoma, and targeted therapeutic approaches to inhibit artemin function in mammary carcinoma warrant consideration.

The glial cell line–derived neurotrophic factor (GDNF) family of ligands (GFLs) comprising of GDNF, neurturin, artemin, and persephin plays an important role in the development and maintenance of the central and peripheral nervous system, renal morphogenesis, and spermatogenesis. Here we review our current understanding of GFL biology, and supported by recent progress in the area, we examine their emerging role in endocrine-related and other non–hormone-dependent solid neoplasms. The ability of GFLs to elicit actions that resemble those perturbed in an oncogenic phenotype, alongside mounting evidence of GFL involvement in tumor progression, presents novel opportunities for therapeutic intervention.

We herein show that Artemin (ARTN), one of the glial cell line-derived neurotrophic factor family of ligands, promotes progression of human non-small cell lung carcinoma (NSCLC). Oncomine data indicate that expression of components of the ARTN signaling pathway (ARTN, GFRA3, and RET) is increased in neoplastic compared with normal lung tissues; increased expression of ARTN in NSCLC also predicted metastasis to lymph nodes and a higher grade in certain NSCLC subtypes. Forced expression of ARTN stimulated survival, anchorage-independent, and three-dimensional Matrigel growth of NSCLC cell lines. ARTN increased BCL2 expression by transcriptional upregulation, and inhibition of BCL2 abrogated the oncogenic properties of ARTN in NSCLC cells. Forced expression of ARTN also enhanced migration and invasion of NSCLC cells. Forced expression of ARTN in H1299 cells additionally resulted in larger xenograft tumors, which were highly proliferative, invasive, and metastatic. Concordantly, either small interfering RNA-mediated depletion or functional inhibition of endogenous ARTN with antibodies reduced oncogenicity and invasiveness of NSCLC cells. ARTN therefore mediates progression of NSCLC and may be a potential therapeutic target for NSCLC.