Study Of The Molecular Mechanism Of Apoptosis Of Colorectal Cancer Cells Induced By 4EGI-1

Objective: Colorectal cancer(CRC)is the most common malignant disease of the digestive system.It is estimated that there are about 1,360,000 newly diagnosed cases of CRC,which results in up to 694,000 deaths every year worldwide.According to the data of the National Cancer Center of China,CRC is the fifth most common and deadly cancer in China.However,there is currently no curative treatment of patients with late-stage CRC.This is closely related to intrinsic and acquired resistance of CRC cells to conventional therapeutic approaches,such as chemotherapy and radiotherapy.Protein synthesis is mainly governed by cap-dependent m RNA translation that is regulated by the eukaryotic initiation factor(e IF)4F(e IF4F)complex,which consists of the cap-binding protein e IF4 E,the ATP-dependent RNA helicase e IF4 A and the scaffolding protein e IF4 G.Among them,e IF4 E is the rate-limiting factor and potentially influences the expression of almost every protein in cells.The assembly of the e IF4 F complex is negatively regulated by e IF4E-binding protein 1(4EBP1)that competes with e IF4 G for binding to e IF4 E.Since cancer cells rely on increased nascent protein production to support their fast proliferation,targeting protein synthesis mechanisms has attracted increasing interest in the treatment of cancer.This has led to the development of the small molecule inhibitor 4EGI-1,which inhibits protein synthesis and displays a potent anti-cancer effect through blocking the physical association between e IF4 E and e IF4 G and promoting the binding of 4EBP1 to e IF4 E.Indeed,4EGI-1 has been demonstrated to be a promising anti-cancer agent in a variety types of cancers,such breast cancer and chronic leukaemia.In this study,we have tested the effect of 4EGI-1 on colon cancer cell survival and proliferation and the mechanisms involved.This thesis shows that treatment with 4EGI-1 is a potential approach in the treatment of colon cancer.Methods: 1.CRC cell lines were treated with different concentrations of 4EGI-1.The effect of 4EGI-1 on the proliferation and apoptosis of CRC cells were detected using MTT and flow cytometry analysis.2.The expression levels of cleaved-PARP,cleaved-caspase-3,Bcl-2,Puma and Noxa proteins were measured by Western blot.3.The effect of 4EGI-1 on the expression of e IF4 E and e IF4 G was evaluated with co-Immunoprecipitation(Co-IP).Results: 1.4EGI-1 could significantly inhibited the proliferation of CRC cell lines.2.4EGI-1 enhanced the expression of cleaved-PARP,cleaved-caspase-3 and induced the apoptosis of CRC cell lines.3.4EGI-1 induced the apoptosis of CRC cell lines by decreased the expression of Bcl-2.4.4EGI-1 could reduce the expression of e IF4 G in CRC cell lines.Conclusion: The small molecule inhibitor 4EGI-1 inhibited the proliferation of CRC cells and induced apoptosis of CRC cells by decreasing the expression of Bcl-2.