Targeted silencing of CDX2 gene with siRNA enhanced vincristine-induced inhibition of proliferation and induction of apoptosis of leukemia K562 cells

Purpose: To determine the effect of targeted silencing of CDX2 with siRNA on vincristine-induced inhibition of proliferation and apoptosis induction in leukemia K562 cells. Methods: K562 cells were divided into untreated group, vincristine group, blank group, and CDX2-siRNA group. The expression of CDX2 gene after CDX2-siRNA transfection was determined by reverse-transcription-polymerase chain reaction (RT-PCR) and immunoblotting, while MTT and flow cytometric procedures were used to evaluate the effect of vincristine on proliferation and apoptotic changes in K562 cells. Results: Protein expression of CDX2 did not change significantly in non-treated cells, vincristine group and blank group, while the expression of CDX2 protein in cells of CDX2-siRNA group was decreased significantly (p < 0.05) while MTT assay results showed that the absorbance of CDX2-siRNA cells was significantly lower than those of the other three groups at 12, 24 and 48 h after CDX2 gene silencing. Flow cytometry showed markedly higher percentage apoptosis of CDX2-siRNA group than in other groups at 12, 24 and 48 h after CDX2 gene silencing. There was no difference in apoptosis level between vincristine group and blank group, but apoptosis was higher in these groups than in untreated group (p < 0.05). Conclusion: Silencing CDX2 gene via targeting with siRNA enhances vincristine-induced suppression of growth and apoptotic changes in leukemia K562 cells, thereby enhancing the anti-tumor effect of vincristine.