Small hairpin RNA targeting at Bcl-2 increases cytarabine-induced apoptosis in Raji cells

Bcl-2, a prominent member of the Bcl-2 family proteins, is responsible for the dysregulation of apoptosis and resistance to chemotherapy. In this study, we investigated whether small hairpin RNA (shRNA) targeting at Bcl-2 mRNA could enhance cytarabine (Ara-C)-induced apoptosis in Raji cells. Bcl-2 shRNA was transfected into Raji cells and the expression levels of Bcl-2 mRNA and protein were assayed by RT-PCR and immunofluorescence. Cell proliferation was determined by MTT assay. Apoptosis was determined by morphological observation and flow cytometric analysis. Our results show that expression levels of Bcl-2 mRNA and protein from Raji cells transfected with Bcl-2 shRNA decreased, compared with either negative control shRNA group or untransfected cells group (P < 0.05). Viability of cells transfected with Bcl-2 shRNA was less than the cells transfected with control shRNA and untransfected Raji cells, respectively (P < 0.05). Bcl-2 shRNA combined with Ara-C significantly inhibited the growth of cells (P < 0.05). There was no difference in cell survival between control shRNA/Ara-C combination and cells treated with Ara-C alone. Using Giemsa staining, cells treated with Bcl-2 shRNA plus Ara-C at 48 h displayed changes of apoptosis. Apoptotic rates of Raji cells treated with Bcl-2 shRNA combined with Ara-C significantly increased (P < 0.05), compared with either control shRNA/Ara-C combination or Ara-C-treated cells alone. Our results suggest that the shRNA against Bcl-2 mRNA could increase Ara-C-induced apoptosis in Raji cells.