Anti-Renal Cell Carcinoma gp200 monoclonal antibody, clone QO-16

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its hypovascularity, with an extremely poor prognosis because of its highly invasive nature. PDAC proliferates with abundant stromal cells, suggesting that its invasive activity might be controlled by intercellular interactions between cancer cells and fibroblasts. Using four PDAC cell lines and two pancreas cancer-associated fibroblasts (CAFs), the expression of insulin-like growth factor-1 (IGF1) and IGF1 receptor (IGF1R) was evaluated by RT-PCR, FACScan, western blot, or ELISA. Correlation between IGF1R and the hypoxia marker carbonic anhydrase 9 (CA9) was examined by immunohistochemical staining of 120 pancreatic specimens. The effects of CAFs, IGF1, and IGF1R inhibitors on the motility of cancer cells were examined by wound-healing assay or invasion assay under normoxia (20% O-2) and hypoxia (1% O-2). IGF1R expression was significantly higher in RWP-1, MiaPaCa-2, and OCUP-AT cells than in Panc-1 cells. Hypoxia increased the expression level of IGF1R in RWP-1, MiaPaCa-2, and OCUP-AT cells. CA9 expression was correlated with IGF1R expression in pancreatic specimens. CAFs produced IGF1 under hypoxia, but PDAC cells did not. A conditioned medium from CAFs, which expressed alpha SMA, stimulated the migration and invasion ability of MiaPaCa-2, RWP-1, and OCUP-AT cells. The motility of all PDAC cells was greater under hypoxia than under normoxia. The motility-stimulating ability of CAFs was decreased by IGF1R inhibitors. These findings might suggest that pancreas CAFs stimulate the invasion activity of PDAC cells through paracrine IGF1/IGF1R signaling, especially under hypoxia. Therefore the targeting of IGF1R signaling might represent a promising therapeutic approach in IGF1R-dependent PDAC.

Chronic inflammation is considered to be one of the risk factors for carcinogenesis. It was recently reported that telomerase plays an important role in inducing such chronic inflammation. Although high telomerase activity is detected in cancer tissues, the activator of telomerase is still unknown. In this study, we used an immunohistochemical method to examine the expression of human telomerase reverse transcriptase (hTERT) in the dysplasia-carcinoma sequence in the oral cavity. Furthermore, the effects of inflammatory cytokines on the telomerase activity and migration of oral cancer cell lines (Ca9-22, HSC-3, and HSC-4) were examined. Immunoreactivity for hTERT was observed in squamous intraepithelial neoplasia 3 and squamous cell carcinoma. Telomerase activity in Ca9-22 cells was increased by treatment with TNF-alpha and INF-gamma, while its activity in HSC-4 cells was decreased by IL-1 beta. Although inflammatory cytokines did not affect the proliferative activity of any of the oral cancer cell lines, cytokines and hTERT siRNA promoted the migration of HSC-3 cells. These results suggest that the presence of long-term chronic inflammation may increase telomerase activity and therefore contribute to malignant transformation of the oral mucosal epithelium. Furthermore, inhibition of telomerase activity by inflammatory stimuli increases the invasion of certain types of oral squamous cell carcinomas.