Enhancing radiosensitivity of Hela cells by combining transfection of bcl-2 c-myc ASODNs.

Abstract

Previous studies have detected bcl2 and c-myc upregulated in Hela cells. In this study, we investigated the effect on apoptosis of Hela cells by combining transfection of bcl2 and c-myc antisense oligonucleotides(ASODNs), and to explore the relationship between combining gene transfection and radiosensitivity of Hela cells, furthermore, to seek a new method to enhance the radiosensitivity of tumor cells. ASODNs of bcl2 and c-myc coated with cationic liposomes were designed and synthesized and transfected to Hela cells. The expressions of BCL2 and C-MYC were assessed by immunohistochemistry (IHC) staining and flow cytometry (FCM), and the induced-apoptosis phenomenon of Hela cells transfected with bcl2 ASODN or c-myc ASODN was observed by Giemsa Staining, DNA Ladder and FCM. Irradiation was performed on ASODNs transfected cells, then the radiosensitivity, biological reaction and cell proliferation of the transfected cells were investigated by cellular clone formation analysis, MTT assay and FCM. Both bcl2 and c-myc ASODNs could partially inhibit the growth of Hela cells by reducing the expression of bcl2 and c-myc (p < 0.05). The apoptosis rate of Hela cells treated with bcl2 ASODN was 6.60 +/- 0.70%, c-myc ASODN 10.29 +/- 0.66%, bcl2 + c-myc ASODNs 11.83 +/- 0.57 %, which were much higher than that of control 1.79 +/- 0.19%(p < 0.05). The sensitivity enhancement ratio(SER) of Hela cells transfected with bcl2 ASODN,c-myc ASODN and bcl2 + c-myc ASODNs was 1.20, 1.53 and 2.18 respectively. Combining transfection of bcl2 and c-myc ASODN could more effectively induce apoptosis of Hela cells, which subsequently enhanced radiosensitivity of Hela cells. Furthermore, combining transfection ASODNs of apoptosis-inhibiting genes or oncogenes followed radiotherapy to malignant tumor cells might be a new potential strategy.