The effect of overexpression of hTERT on etoposide (VP-16)-induced apoptosis in Raji cells

Abstract

To explore whether overexpression of human telomerase reverse transcriptase (hTERT) in Raji cells can protect against etoposide (VP-16)-induced apoptosis. A lipofectin-mediated gene transfection method was used to transfer the hTERT gene into Raji cells. The polymerase chain reaction enzyme-linked immunoassay was employed to determine telomerase activity. The expression levels of hTERT protein were assayed by immunofluorescence using a fluoresce isothiocyanate label. Cell viability was determined using the trypan blue dye exclusion assay. Apoptosis was assessed by morphological observation and flow cytometry analysis. The results showed that there was a marked increase in both mean fluorescence intensity of hTERT-protein-positive cells and telomerase activity in hTERT-transfected Raji cells (P 0.05). There were more viable cells at 48 h and 72 h after treatment of hTERT-transfected Raji cells with 10 Μmol/L VP-16 compared to either vector-transfected Raji cells and Raji cells (P <0.05). Apoptosis rates at 72 h after treatment with 10 Μmol/L VP-16 were 4.34 ±1.03% in hTERT-transfected Raji cells, 33.21 ± 3.12% in vector-transfected Raji cells, and 31.63 ± 3.06% in Raji cells. There was a significant difference in the percentage of apoptotic cells between hTERT-transfected Raji cells and either vector-transfected Raji cells or Raji cells (P<0.05). Overexpression of telomerase by transfection of hTERT gene can protect against etoposide-induced apoptosis in Raji cells.