Effects of replication defective adenovirus to apoptosis and autophagy pathways on tumor cell lines

Adenoviruses are used in molecular biology for high-efficiency gene transfer frequently. Adenovirus infecting its host causes cell death by inducing the Apoptosis Pathway, which is called the death mechanism. Apoptosis is a process that cell encounter in their usual physiological process to prevent various diseases, including cancer. Autophagy, which is also cytoprotective mechanism, also causes cell death in the adenoviral infection process. Replication-defective adenoviruses are used in gene therapy studies generally. These viruses are not expected to cause cell death like the wild-type adenovirus. There are incompleted studies on the apoptosis and autophagy-inducing potential of replication-defective adenoviruses. In our thesis study, the effect of a recombinant adenoviral vector developed for COVID-19 vaccine treatment and used in clinical studies which is called CoVacHG (Ad-spike protein) on the expression of genes that are effective in apoptosis and autophagy in cells, was investigated at both mRNA and protein levels. In normal cell infected with CoVacHG, the protection mechanism was activated, whereas the cells did not die. These results suggest that adenoviral vectors may be safe as vaccine vectors in healthy individuals. In addition, the effects of the Ad-CD-GMCSF vector designed as a cancer vaccine on apoptotic and autophagic genes were investigated at both mRNA and protein levels. According to the results obtained, in normal cell infected with Ad-CD-GMCSF, the protection mechanism was activated. In the cancer cells, different results were obtained according to the cancer type. That was found that the cells in lung cancer cells were more sensitive to the vaccine, while breast cancer cells were more resistant. Therefore suggested that adenoviral vector vaccine does not induce breast cancer cells to apoptosis.