Human Gyrovirus Apoptin as a Potential Selective Anticancer Agent: An In Vitro Study

Abstract

Background: Selective therapy has always been the main challenge in cancer treatments. Recently, it has been shown that Human Gyrovirus-derived protein apoptin (HGV-Apoptin) has selective cytotoxic effects on cancer cells similar to its homologue, Chicken Anemia Virus-derived Apoptin (CAV-Apoptin). However, apoptotic effects of Human Gyrovirus apoptin have been only evaluated on a few cancerous cell lines and need to be further investigated. In this study, we have evaluated the apoptotic effects of HGV-Apoptin and CAV-Apoptin expression on lung cancer (A549) and normal (HEK-293) cell lines, in order to provide more information about the specificity of these proteins on cancerous cells. Methods: Target cells were transfected by the calcium-phosphate precipitation method with constructed plasmids expressing HGV-Apoptin and CAV-Apoptin proteins as well as the control plasmid. Transfection efficiency was followed and imaged by fluorescence microscopy. Quantification of apoptosis was performed by flow cytometry. Measurements were compared by paired Student t-test. Results: Cells were successfully transfected with control and constructed plasmids. Flowcytometry analysis showed that A549 cells transfected with HGV-Apoptin and CAV-Apoptin expressing plasmids, undergone the apoptosis compared to A549 cells transfected with control plasmid (P<0.001). None of the plasmids could induce apoptosis in HEK-293 cells. Conclusion: Human Gyrovirus-derived apoptin (HGV-Apoptin) similar to its homologue, chicken anemia virus derived Apoptin (CAV-Apoptin) can induce apoptosis in Non-small-cell lung carcinoma cell line A549, but not in normal human embryonic kidney cell line HEK-293, which can be introduced as a promising novel specific antitumor agent.

Keywords: Apoptin, Human gyrovirus, Apoptosis, Tumor specificity, Cancer therapy