Résumé
Objective To identify small molecule inhibitors of APC-mutant colon cancer and provide lead compounds for targeted therapy of colon cancer. Methods APC-mutant colon cancer cell lines that stably express 7*Tcf-GFP/SV40-Cherry (7TGC) dual fluorescence reporter system was constructed for small-molecule inhibitor screening. Cell viability, colony formation, EdU incorporation, and xenograft tumor assay were used to evaluate the inhibitory effect of these inhibitors on APC-mutant colon cancer in vitro and in vivo. Western blot and co-immunoprecipitation assays were used to explore the molecular mechanism. Results Four small molecules that inhibited Wnt activity in APC-mutant colon cancer cells were discovered. Shikonin exhibited significant inhibition of cell viability and proliferation while inducing apoptosis of APC-mutant colon cancer cells. Xenograft tumor assay demonstrated that shikonin significantly reduced tumor growth in vivo. Furthermore, Western blot and co-immunoprecipitation assays revealed that shikonin markedly decreased β-catenin levels. Conclusion Shikonin effectively inhibits Wnt activity and suppresses tumor growth in APC-mutant colon cancer.
Résumé
Objective To explore the antitumor small molecules targeting the ubiquitin–proteasome system (UPS) on the basis of active molecules from traditional Chinese medicine. Methods UbG76V-GFP stably expressing cell line was constructed to screen novel small molecule inhibitors targeting UPS. The fluorogenic substrates of Suc-LLVY-AMC, Z-LLE-AMC, and Boc-LRR-AMC were used to assess the effect of dioscin on the 20S proteasome hydrolase activity. The Ub-AMC substrate was used to evaluate the effect of dioscin on the intracellular deubiquitinating enzyme activity. Western blot was used to detect the effect of dioscin on intracellular ubiquitination levels. CCK-8 and colony formation assays were used to detect the inhibitory effect of dioscin on the tumor cell proliferation. Results Dioscin is a UPS inhibitor discovered through the UbG76V-GFP reporter system. It enhances intracellular ubiquitination and inhibits tumor cell proliferation and colony formation by targeting deubiquitinating enzymes. Conclusion Dioscin could significantly inhibit tumor cell proliferation by targeting ubiquitin–proteasome.
Résumé
AIM: To examine the expression of human endostatin in E.coli , produce its fusion protein antibody and observe its biological activity. METHODS: Endostatin gene was amplified by polymerase chain reaction,recombined with plasmid vector pGEX-2T and induced expression with IPTG.The protein activity was tested by endothelial cell proliferation inhibitory assay.Inclusion body crudely purified was used to generate polyclonal antibody to detect its expression at mouse's liver and kidney etc. RESULTS: The protein expressed was 20 kD after digestion by thrombin,it appeared the anti-angiogenesis activity and Western blotting indicated the expression of endostatin in liver and kidney of mouse. CONCLUSION: The successful expression of human endostatin and the preparation of polycolonal antibody indicated its potential application in anti-angiogenesis therapy and diagnosis tumors.