Effects of NHE-1 antisense gene on cell proliferation and apoptosis of drug-resistant human small cell lung cancer cells

Objective To evaluate the effects of cell acidosis and apoptosis of Na~+/H~+ exchanger- 1 (NHE-1) antisense gene on drug-resistant human small cell lung cancer(SCLC) H446/DDP cells.Meth- ods An expression recombinant of antisense gene was constructed with the NHE-1 gene and a retroviral vector.It was transfected to drug-resistant human small cell lung cancer (SCLC) cell line H446/CDDP cells.Intracellular pH (pHi) values were measured with fluorescence spectrophotometer.The proliferation of cancer cells was assayed by cytometry.The expression of apoptosis gene of cancer cells was assayed by immune histochemical method.The cell apoptosis of Na~+/H~+ exchanger-1 (NHE-1) antisense gene on drug-resistant human small cell lung cancer(SCLC) H446/DDP cells was observed by flow cytometry.The apoptosis of cancer cells was observed by transmission electron microscopy.Results An expected recombi- nant was successfully constructed.Compared with the control group,transfected with void vector(7.25±0.02), pHi value decreased significantly to 6.86±0.01 in recombinant-transfected H446/CDDP cells (P0.01). The cell proliferation decreased at 48 h after antisense gene transfection.There was expression of apoptosis gene Caspase3 in recomhinant-transfected H446/CDDP cells,but not in the control group.Both flow cytom- etry and transmission electron microscopy revealed apoptosis in the recombinant-transfected H446/CDDP cells.Conclusion The NHE-1 antisense gene can induce acidification of drug-resistant human SCLC H446/CDDP cells,and may play an important role in apoptosis of drug-resistant human SCLC H446/CDDP cells.