Ror2, a Developmentally Regulated Kinase, Is Associated With Tumor Growth, Apoptosis, Migration, and Invasion in Renal Cell Carcinoma

Renal cell carcinoma (RCC) represents one of the most resistant tumors to radiation and chemotherapy. Current therapies for RCC patients are inefficient due to the lack of diagnostic and therapeutic markers. The expression of novel tumor-associated ldnases has the potential to dramatically shape tumor cell behavior. Identifying tumor-associated kinases can lend insight into patterns of tumor growth and characteristics. In the present study, we investigated the receptor tyrosine kinase-like orphan receptor 2 (Ror2), a new tumor-associated ldnase, in RCC primary tumors and cell lines. Knockdown of Ror2 expression in RCC cells with specific shRNA significantly reduced cell proliferation and induced apoptosis. Using in vitro migration and Matrigel invasion assays, we found that cell migration and invasive ability were also significantly inhibited. In RCC, Ror2 expression correlated with expression of genes involved at the cell cycle and migration, including PCNA, CDK1, TWIST, and MMP-2. Furthermore, in vivo xenograft studies in nude mice revealed that administration of a Ror2 shRNA plasmid significantly inhibited tumor growth. These findings suggest a novel pathway of tumor-promoting activity by Ror2 within renal carcinomas, with significant implications for unraveling the tumorigenesis of RCC.