[Rituximab-mediated sensitization of B-NHL cell lines to apoptosis induced by gemcitabine and Navelbine in vitro].

This study was purposed to explore the Rituximab (RTX)-mediated sensitization of B-NHL cell lines to apoptosis induced by Gemcitabine or Navelbine and its possible mechanism. The inhibitory rate of B-NHL cell proliferation was detected by XTT method, the IC50 from Gemcitabine or Navelbine and combination of Gemcitabine or Navelbine with RTX was compared. The expression level of antiapoptotic protein BCL-2 in Daudi, Ramos, Raji and Namalwa cells treated with RTX of 20 µg/ml for 24 hours was detected by Western blot. The results showed that the RTX as a single agent could weakly induce the apoptosis of Daudi, Namalwa, Raji and Ramos lymphoma cell lines, the inhibiting rate of cell proliferation ranged from 3% to 10%; RTX could sensitize significantly the cytotoxity of Gemcitabine or Navelbine in Daudi, Namalwa and Raji cell lines; The expression of BCL-2 in Raji and Namalwa cell lines treated with RTX of 20 microg/ml for 24 hours was down-regulated. It is concluded that RTX can sensitize the cytotoxicity of Gemcitabine or Navelbine to the human lymphoma cell lines which displayed the synergistic effect on Daudi, Namalwa and Raji cell lines. The BCL-2 expression level in Raji and Namalwa cell lines treated by RTX is down-regulated which may be one of the mechanisms sensitizing the cytotoxicity of Gemcitabine or Navelbine.