Design and construction of recombinant oncolytic adenoviruses for the treatment of gastric cancer cell lines: a viral vector-based approach

Oncolytic viral therapy is known as promising approach for cancer treatment. Oncolytic viruses like adenoviruses can proliferate in cancerous cell and disintegrated these cells.  Serotype 5 adenovirus attached on surface of host cell via coxsackie-adenovirus receptors. The expression rate of this receptor is highly variable in surface of cancerous cells. The aim of the present study was production of an oncolytic adenoviruses with high selectivity feature for gastric adenocarcinoma cells (AGS) that can proliferate in this cell and destroy them.

In this experimental study, the octreotate sequence was cloned into HI-loop of the adenovirus fiber. Thus, the pAd5TATE (wt) and pAd5TATE (ΔE1, ΔE3) recombinant vectors were constructed. pAdZ-TATE (wt) vector was synthesized using pADZ cloning system. Ad5TATE (wt) and Ad5TATE (ΔE1, ΔE3) recombinant viral particles were synthesized and propagated in HEK293 cells. Using the calcium phosphate procedure, the HEK293 cell line was transfected with the recombinant vectors and the new virus particles were produced. The AGS cell line was transfected by the Ad5 (wt) and Ad5TATE (wt) and the cell destruction of these cells were investigated in different times. Using the MTT test the cell surveillance rate was evaluated in AGS cell line that treated with recombinant vector. Cell destruction effects (CPE) started in less than 18 hours and were completed 72 hours after infection.

The titer of recombinant viruses was calculated by the TCID50 method as 107 (for 100 Lµ of viral solution). Also, Ad5TATE (ΔE1, ΔE3) virus titer was 107 TCID50/ml by the TCID50 method. The results showed that Ad5TATE (wt) could infect AGS cells compared to Ad5(wt). The results of the MTT test showed that with the increase in the concentration of viral particles and storage time, the number of live AGS cells decreased significantly.

The findings of this research showed that the Ad5TATE (wt) recombinant virus could specifically infect gastric adenocarcinoma (AGS) cancer cells and destroy them after replication. Therefore, the Ad5TATE (wt) virus can be used as an oncolytic agent against gastric adenocarcinoma (AGS) cancer cells.