Screening Of Anti-pancreatic Cancer Compounds Based On Hsp90-Cdc37 Interaction In Vitro

Pancreatic ductal adenocarcinoma also known as pancreatic cancer, ranked fourth among cancer-related deaths. Pancreatic cancer is more common in elderly persons than in younger persons, and less than 20% of patients present with localized, potentially curable tumors. The overall 5-year survival rate among patients with pancreatic cancer is< 5%.The treatment regimens for pancreatic cancer have nosubstantial improvement over the past few decades. Currently,surgery is the main therapeutic option since chemotherapy andradiation only achieve minimal effects due to rapid progression,late diagnosis, and drug resistance of pancreatic cancer.Unfortunately, only 15-20% of pancreatic cancer patients areamenable to curative resection while 80% of patients generallyhave nonresectable advanced or metastatic tumors. Furthermore, even in patients with resectable disease, the overall 5-yearsurvival is 15%. Currently, gemcitabine is the standard therapeutiodrug for treatment of pancreatic cancer. However, it only improvesthe disease symptoms with no significant survival benefits.Recent researches found that Hsp90 played an important role in cacner. compared with normal condition, the expression extent of Hsp90 is two fold than normal cell, this indicated that Hsp90 played an important role in the proliferation and survival of cancer cell, while the intertaction between Hsp90 and Cdc37 is very important in the development of pancreatic cancer. Therefore, the strategy of block Hsp90 and Cdc37interaction against pancreatic cancer has been bring out. There is more specifity and less side effects to block the interaction between Hsp90 and Cdc37, and therefore, It is a new strategy for treatment of pancreatic cancer.Inspecting the history of drug development during thepast half century demonstrates that natural resources representa significant segment on the pharmaceutical marketcompared to randomly synthesized compounds. As compiledby the World Health Organization, more than 21,000 plant species have been used worldwide in herbalmedicines. Herbs are an important source for drug development.The traditional Chinese medicine (TCM) holds an important position in primary health carein China and has been recently recognized by Westerncountries as a fertile source for revealing novel lead moleculesfor modern drug discovery.Numerous researches have found that many natural products possess potent anticancer activity, such as terpenoids, alkaloids and flavonids. Therefore, it is an easy way to screen active compounds from natural products. However, it is a tedious and time-consuming work to identifyactive compounds from herbal ingredients by using traditionalscreening methods. Therefore it is urgent to developa high-throughput method for screening active compoundsbased on some specific targets.The first part is literature searching. Literatures related about natural products that possess anti-cancer activity are searched, and 600 active compounds are collected. Then the anti-cancer natural products were builded.The second part is the construction of Hsp90/Cdc37 interaction model in vitro. In this section, Hsp90/Cdc37 interaction model was established by SRL-PFAC technique for screening potentialanti-pancreatic cancer candidate compounds. Theparameters which would influence the screening model wereoptimized. Under the optimized conditions, the screeningmodel was successfully validated by 4 natural products and then applied to screen a series of natural products. Finally,4 natural products were found to possess the effect of block the interaction between Hsp90 and Cdc37, and in which triptolide possess the most strongest effect.The third part is a systematic evaluatin of absorption and metabolism characteristics, In the early era of drug development, using the in vitro model to investigate the absorption and metabolism properties, and rule out those poor drugability compounds can avoid unnecessary waste of manpower and financial resources. In this part, Caco-2 cell transwell model and rat liver microsome incubation systems were applied to evaluating the characteristics of the these natural products, and then triptolide was chosed to possess good absorption and metabolism characteristics, finally, the pharmacokinetics parameters were investigated.In this research, a screening method for anti-cancer candidate compounds based on the Hsp90/Cdc37 interaction model in vitro by Split Renilla luciferase protein fragment-assistedcomplementation bioluminescence technology was established. Using this screening method, natural products blocking the interaction between Hsp90-Cdc37 interaction can be screened targetly and quickly. Using this method,4 natural products (triptolide, quercetin, gambogic acid and sophocarpine) were screened to block the interaction between Hsp90-Cdc37, Finally, the absorption and metabolism properties were investigated systematically. In this research, a rapid screening method was set up and can improve the targeting and efficiency of anti-pancreatic cancer drug screening.