Recombinant Oncolytic Adenovirus Combined with Cyclophosphamide Induces Synergy in the Treatment of Breast Cancer in vitro and in vivo

Abstract

Jing Wang,1 Shuting Zuo,1 Yan Zhang,1 Shanzhi Li,2 Ying Shi,1 Tonghua Du,1 Jicheng Han,2 Ningyi Jin,2– 4 Yiquan Li,2 Xiao Li2,3 1Department of Breast Surgery, The Second Hospital of Jilin University, Changchun, 130000, People’s Republic of China; 2Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Changchun, 130117, People’s Republic of China; 3Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, 130122, People’s Republic of China; 4Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People’s Republic of ChinaCorrespondence: Yiquan Li; Xiao Li, Academician Workstation of Jilin Province, Changchun University of Chinese Medicine, Liuying West Road, 666, Jingyue Economic & Technological Development Zone, Changchun, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]; [email protected]: Oncolytic virus therapy has gradually become an integral approach in cancer treatment. We explored the therapeutic effects of the combination of a dual cancer-selective anti-tumor recombinant adenovirus (Ad-Apoptin-hTERTp-E1a) and cyclophosphamide on breast cancer cells.Methods: The inhibition of MCF-7 and MDA-MB-231 breast cancer cells by Ad-Apoptin-hTERTp-E1a (Ad-VT), cyclophosphamide, and Ad-VT + Cyclophosphamide was investigated using the CCK-8 assay. The combination index (CI) was calculated using CalcuSyn software to determine the best combination based on the inhibition rates of the different treatment combinations. The CCK-8 assay and crystal violet staining were used to detect the cytotoxicity of the combined Ad-VT and cyclophosphamide in breast cancer cells and breast epithelial cells. Subsequently, Hoechst staining, annexin V flow cytometry, and JC-1 staining were used to analyze the inhibitory pathway of Ad-VT plus cyclophosphamide on breast cancer cells. Cell migration and invasion of breast cancer cells were assessed using the cell-scratch and Transwell assays. The anti-tumor effects of different treatment groups in a tumor-bearing nude mouse model also were analyzed.Results: The treatment combination of Ad-VT (40 MOI) and cyclophosphamide (400 μM) significantly inhibited MCF-7 and MDA-MB-231 cells and reduced the toxicity of cyclophosphamide in normal cells. Ad-VT primarily induced breast cancer cell apoptosis through the endogenous apoptotic pathway. Apoptosis was significantly increased after treatment with Ad-VT plus cyclophosphamide. The combination significantly inhibited the migration and invasion of MCF-7 and MDA-MB-231 cells. The in vivo experiments demonstrated that exposure to Ad-VT plus cyclophosphamide significantly inhibited tumor growth and extended the survival time of the nude mice.Conclusion: Ad-VT plus cyclophosphamide reduced toxicity and exhibited increased efficacy in treating breast cancer cells.Keywords: cyclophosphamide, recombinant adenovirus, breast cancer, synergy, toxicity

Keywords

• cyclophosphamide
• recombinant adenovirus
• breast cancer
• synergy
• toxicity