Study On The Interaction Between 3-biotin-B-nor Cholesteryl Benzimidazole Derivatives And Ct-DNA And The Mechanism Of Anti-breast Cancer

Steroid compounds have a polycyclic skeleton structure,which plays an i mportant role in maintaining normal physiological functions.Introducing heteroa tom and heterocyclic substituents into steroid parent nucleus can change its ori ginal biological activity and make it have antibacterial,anti-inflammatory and a nti-cancer properties.It is widely used in medicine,biology,agriculture and oth er fields.The B-nor cholesterol benzimidazole compound synthesized by our res earch group has a good anti-tumor activity and a good inhibitory effect on tu mor cells,especially human ovarian cancer cells(SKOV3).Based on this,we synthesized a series of 3-biotin-B-nor cholesteric benzimidazole derivatives by i ntroducing biotin into steroid mother nucleus 3 site.In this study,3-biotin-B-no r cholesteric benzimidazole derivatives were used as the research object to expl ore the interaction between these compounds and ct-DNA and the anti-breast c ancer mechanism,and further study the biological properties of steroid compou nds to down-regulate estrogen receptor ERα.The research contents are divided into three parts: 1.The interaction mechanism between 3-biotin-B-nor cholesteri c benzimidazole derivatives and ct-DNA was studied under similar physiologica l conditions.2.To investigate the anti-breast cancer mechanism of 3-biotin-B-n or cholesteric benzimidazole derivatives in MCF-7 cells.3.Several different ty pes of steroid compounds were selected for the screening of estrogen receptor(ERα)regulation,which provided reference for the further study on the applica tion of steroid compounds in the anti-breast cancer mechanism.Specific research contents are as follows:1.The interaction mechanism between three different types of 3-biotin-B-n or cholesteric benzimidazole derivatives and ct-DNA was studied by using spec troscopic methods(such as ultraviolet spectroscopic method,fluorescence spectr oscopic method,circular dichroism spectroscopic method,etc.),viscosity spectro scopic method,molecular docking technique and other methods.UV spectra sh owed that,all of these compounds could induce the chromaticity effect of ct-D NA,and it was preliminarilyconcluded that the interaction mode of both comp ounds was mainly groove action,and compound 3 May be accompanied by ele ctrostatic action.Fluorescence spectrum can verify that the combination of com pound and ct-DNA is groove action,indicating that the fluorescence quenching process in which the two interact is static quenching.The results of the circu lar dichroism spectra showed that these compounds could not change the positi ve peak formed by the accumulated base pairs of ct-DNA,and the negative pe ak of the right hand helix of ct-DNA showed slight decoloration.From the vis cosity test,there was no significant change in the viscosity of the compound when it interacted with ct-DNA,indicating that the two compounds acted as gr ooves.The molecular docking results showed that the three compounds all inter acted with ct-DNA mainly in groove mode,and all of them had weak electrost atic interaction,among which compound 3 was slightly stronger.2.Detection of in vitro antitumor activity of 3-biotin-b-nor cholesteryl be nzimidazole derivatives showed that they had good cytotoxic activity,compoun ds could inhibit the migration of MCF-7 cells and change their cell morpholog y.The effects of compounds on MCF-7 apoptosis were analysis.The results sh owed that they could induce MCF-7 apoptosis in a certain concentration range,and the concentration was too high to enter the stage of necrosis.The expres sion of p53、MDM2、C-myc、ERα and other genes after the action of compou nds was also detected,and p53-MDM2 cascade reaction was found.3.The ERα activity of several steroid compounds against MCF-7 cells wa s screened by Cignal ERE Reporter(Luc)Kit and double luciferase assay Kit.Further study of estrogen receptor ERα down-regulation.