The Research On The Treatment Of Triple Negative Breast Cancer With Oncolytic Adenovirus SG400-E2F/IL15

Background and Objective:In women,breast cancer is one of the most frequently diagnosed malignant neoplasm.The triple negative breast cancer has become research hotspots because of higher degree of malignancy and poor prognosis.Oncolytic virus is a type of naturally occurring or artificially transformed virus.It can selectively infect and lyse tumor cells but has little effect on normal cells so as to play a role in inhibiting tumor growth.In order to improve targeting,researchers often construct oncolytic adenovirus using tumor specific promoter.Cell cycle related transcription factor E2F-1 is highly expressed in some solid tumors(like liver cancer?lung cancer).By using this character,oncolytic virus targeting this gene was tested in animal models such as liver cancer etc and can inhibit tumor growth.This is a good choice for gene therapy of breast cancer.To improve the anti-tumor effect and optimize anti-tumor immune response,researchers use the gene engineering method to make the virus express different immunomodulatory factors(like interleukin 15?interleukin 12).In this research,we use E2F1 promoter to construct oncolytic adenovirus,make the virus express IL-15.Assess the treatment effect of triple negative breast cancer with oncolytic adenovirus.Methods:1?Three adenoviral vectors were constructed,including E2F-1 promoter oncolytic virus SG400-E2F1,SG400-E2F/IL15 and SG400-EGFP(as control virus).2?Breast cancer cell line MDA-MB-231 and the normal fibroblast cell line MRC-5 were infected with adenovirus SG400-EGFP.The result was observed under the fluorescence microscope.MTT assay was performed to detect the inhibitory effect of the virus on the two cell lines.ELISA was performed to detect the level of IL-15 in the supernatant after cells were infected with virus,Western blotting was performed to detect the intracellular IL-15 protein.3?Establish the mouse model of breast cancer.The optical imaging in vivo system was used to monitor the growth.Results:1?We successfully constructed the oncolytic adenovirus SG400-E2F1 and SG400-E2F/IL15.2?SG400-EGFP has been selective.SG400-E2F/IL15 could kill the breast cancer cells while hardly kill the normal cells.The level of IL-15 in breast cancer cells increased more obviously than the normal cells.3?In the mice model,the volume and photon number of the tumors in the SG400-E2F/IL15 group was significantly less than those in other groups(P<0.05)and had greater anti-tumor effect than either groups.Conclusions:E2F-1 promoter oncolytic viruses can selectively kill triple negative breast cancer cells.E2F-1 promoter oncolytic adenovirus expressing IL-15 has more effective anti-tumor effect.