Therapeutic potential of targeting protein for Xklp2 silencing for pancreatic cancer.

The targeting protein for Xklp2 (TPX2) is a microtubule- and, cell cycle-associated protein who's overexpression has been reported in various malignancies. In this study, we verified the overexpression of TPX2 in both surgically resected specimens of pancreatic cancer and multiple pancreatic cancer cell lines. Subsequently, we found that TPX2 siRNA effectively suppressed the proliferation of pancreatic cancer cells in culture, and the direct injection of TPX2 siRNA into subcutaneously implanted pancreatic cancer cells in nude mice revealed antiproliferative effects. These results implied a therapeutic potential of TPX2 siRNA in pancreatic cancer. Among 56 angiogenesis-related factors examined using angiogenesis arrays, the average protein levels of insulin-like growth factor-binding protein-3 (IGFBP-3) were significantly higher in TPX2 siRNA-treated tumors than in the Control siRNA-treated tumors. Moreover, we demonstrated that CD34-positive microvessels were significantly reduced in tumors treated with TPX2 siRNA compared to tumors that treated with Control siRNA. The attenuated expression of CD34 in TPX2 siRNA-treated tumors coincided with the overexpression of IGFBP-3. These results indicated that TPX2 has an impact on tumor angiogenesis in pancreatic cancer. The results also implied that the antiangiogenic effect observed in TPX2 siRNA-treated pancreatic cancer cells may be partly explained by the upregulation of IGFBP-3.