The deletion of adenovirus E1B-19KD gene enhanced its cell killing ability against lung cancer cell line A549

Abstract

Oncolytic Viruses immunotherapy is one of the most frequently used anti-cancer agents because it can significantly reverse local immune suppression and amplify antitumor immunity. Although drugs were already applied in cancer treatment, a new agent may open a new pathway for developing oncolytic therapy. This study intends to improve the adenoviral vector to increase its killing effect on tumor cells for effective and safe cancer gene therapy. We modified the pDC316 plasmid by adding TERT promoter, E1A, and E1B viral genes through homologous recombination and transfection. Then the virus was reassured of its stability through PCR analysis, Western blot, viral titer assays, and CPE assay. In the result, Ad-E1B 55k virus especially showed strong cytotoxicity of more than 50% of killing efficacy in vivo A549 cells. Cell viability in HepG2 is around 80% while in MRC5 cells, the viability is approximately 100%, which showed a tumor-specificity of the viruses. Moreover, only on day 4 has 20% of the efficacy of E1B 55k virus and the viability quickly returned to normal on the next day, which indicates the relative safety of the modified in MRC5 normal cells. In conclusion, the modified virus may serve as another starting point to design a potentially safer, better efficacy, and specificity in cancer immunotherapy. However, a further test of the vector in animal trials is recommended.