Evaluating Antitumor Efftct Of Icotinib For Pancreatic Cancer Preclinicall By PDTT Mouse Modles

Pancreatic adenocarcinoma is one of the most aggressive malignancies, with modality nearly equal to its incidence. Even though surgical resection is potentially curative, the vast majority of patients present with advanced stage disease and palliative chemotherapy remains the treatment of choice in the management of these patients. So, to improve the outcome of pancreatic cancer, the best way is to refine the medicine strategies. Despite intensive clinical and pre-clinical research over the last few years, the considered standard cytotoxic drug in the treatment of these patients is anti-metabolite drug gemcitabine, regards to targeted agents, erlotinib is the only one, for its minimal or modest efficacy combined with gemcitabine. Therefore, seeking for novel agents and therapeutic approaches is currently most urgent task for this fatal disease.Similarly to erlotinib, icotinib is a small-molecule inhibitor of EGFR tyrosine kinase developed by Zhejiang Bata Pharma Ltd. It has shown positive clinical antitumor activities in advanced NSCLC patients, and has been approved by the State Food and Drug Administration (SFDA) of China. Based on its biologic feature and clinic performance, icotinib is a promising candidate for pancreatic cancer management.Recent years, though thousands of biologic agents have been developed, and showed positive results in preclinical study, most of these finally fail to be proved in clinic. The most possible reason for this disparity is that the models used in the preclinical study have a poor representativeness for clinic cancer patients. Recently, patient derived human tumor tissue (PDTT) xenograft model has been proved retaining similar features with the original cancer, it is considered to be a better platform for integrating drug screening.Purpose:To establish pancreatic PDTT mouse models for preclinic study. And via this platform to evaluate the antitumor effect of icotinib for pancreatic cancer, and try to clue the relative mechanism.Methods:Establishment of pancreatic PDTT models:Tumor specimens were acquired for operative patients of pancreatic cancer (GO) and seeded subcutaneously in nude mice. After tumor is grown up, we passaged tumor mice to mice at least three times (G1-G3). Then, we confirmed the xenografts are similar to its derived tumor and used G3to evaluate icotinib. In this procession, we separated pancreatic cells from one models for next study.Antitumor effect study in vitro:establishing a pancreatic cancer cell line for a PDTT model, then MTT assay was performed to evaluate the effect of icotinib alone or in combination with gemcitabine on pancreatic cancer cell lines.In this study, NSCLC cell A549was used as a cell control and erlotinib was used as positive drug control.Antitumor effect study in vivo:The third generation of pancreatic PDTT grafted mice was treated with icotinib. During treating duration, we measured the volume of tumors periodically to verify the effect of icotinib on these tumors; weigh the weight of mice to learn the adverse reaction. After the treatment, tumor tissue were collected for next molecular study.Mechanisms studies:Western Blot was carried out to analyze changes of EGFR and relative molecules. For the animal study, results were confirmed by immunohistochemistry (IHC).Results:PDTT xenograft models of pancreatic ductal adenocarcinoma were successfully established. Early passages of the PDTT xenograft models revealed a high degree of similarity with the original clinical tumor with regard to histology, proteins expression as well as gene mutation.In vitro, growth of Panc-1cells, Capan-1cells and Panc004C cells were efficaciously inhibited by icotinib in a dose dependent manner. Adding icotinib to combination with gemcitabine, cell growth inhibition of latter was significantly enhanced; Icotinib can significantly inhibit EGF-induced EGFR and Erk phosphorylation in human pancreatic cancer cell lines.In PDTT models, icotinib suppressed tumor growth and enhanced the antitumor effect of gemcitabine. Molecular analysis revealed that icotinib inhibited the phosphorylation of Erk activated by Gemcitabine in vitro and in vivo.Conclusion:4PDTT xenograft models of pancreatic cancer were established, they showed high degree of similarity with the original clinical tumor with regard to histology, proteins expression as well as gene mutation. Thus, pancreatic cancer PDTT xenograft model is an appropriate model for preclinic study.Icotinib can inhibit pancreatic cancer in vitro and in PDTT model, and enhance the anti-tumor efficacy of gemcitabine even in Kras mutated pancreatic cancer by inhibiting amplified MAPK signaling.