Examination of the effects of overexpressed FOXO3 gene in hek293 cell line

Objective: FOXO proteins are important transcription factors involved in the regulation of functions such as cell homeostasis, oxidative stress response and apoptosis. Also, FOXO proteins have been identified as tumor suppressors and translocations of FOXO genes have been linked to carcinogenesis. The translocation of FOXO3 gene with MLL gene has been associated with secondary acute leukemia. FOXO proteins are involved in carcinogenesis and FOXO3 initiates apoptosis in certain cell types. Hence apoptosis process will be examined by overexpression of FOXO3 gene in HEK293 cell line. Method: In this study, FOXO3 gene were inserted into the expression vector pcDNA3.1 with using PCR cloning strategies. mRNA coding sequences of pcDNA3.1 vector contains active promoter providing high gene expression. HEK293 cells were transiently transfected with the FOXO3 / pcDNA3.1 vector. The protein isolates obtained from the transfected cells therefore analyzed for FOXO3, beta-actin and PARP proteins by western blotting. Results: Hek293 cell line transfected with pcDNA3.1 / FOXO3 vector. We showed 1.5-fold increase in FOXO3 expression in transfected cells against to the control cells. When we exaimed spontaneous apoptosis without giving any apoptotic stimulation to the cell culture after the same transfection, we found apoptotic stimulation occurs in FOXO3 transfected cells by PARP analysis. Conclusion: Our experiments showed that overexpression of FOXO3 gene induces apoptosis in the cell.