[A study on the apoptosis of gastric carcinoma cells induced by arsenic trioxide combined with Ad-IkappaBalphaM].

OBJECTIVE

To study the activation of nuclear factor-kappaB (NF-kappaB) in gastric carcinoma SGC-7901 cells after treating with As(2)O(3) and the enhancement of the therapeutic effect of As(2)O(3) with recombinant adenovirus IkappaBalphaM.

METHODS

Culture of gastric carcinoma SGC-7901 cells was carried out. The cells both uninfected and infected with Ad-IkappaBalpha but not treated with As(2)O(3) were used as control. Electrophoretic mobility shift assay (EMSA) and immunohistochemistry were used to detect the activation of NF-kappaB in the cells after treatment of As(2)O(3) and the combination with Ad-IkappaBalphaM. MTT, Hoechst staining and TUNEL were used to assay the change of apoptosis induced by As(2)O(3) after infection with Ad-IkappaBalphaM.

RESULTS

The results of EMSA and immunohistochemical method showed that after the treatment of As(2)O(3) the cells showed high activity of NF-kappaB. Simultaneous infection with Ad-IkappaBalphaM can inhibit the activation of NF-kappaB; MTT method indicated that after the treatment of As(2)O(3) infected with Ad-IkappaBalphaM apoptosis rate of the cells (59.2 +/- 2.5)% was higher than that of the cells treated with As(2)O(3) and infected with Ad-IkappaBalpha but not treated with As(2)O(3) (47.5 +/- 2.3)% and these neither infected nor treated (40.0 +/- 1.2%), P < 0.01. The result of Hoechst staining method indicated that, in the group of cells treated with As(2)O(3) and infected with Ad-IkappaBalphaM, apoptosis rate is (27.7 +/- 2.6)%, which was higher than the that of the cells infected with Ad-IkappaBalpha (18.3 +/- 1.5)% but not treated with As(2)O(3) and these neither infected nor treated (11.0 +/- 1.7%), P < 0.05. Hoechst staining method was in accordance with TUNEL technique; it was shown that in the group of cells treated with As(2)O(3) and infected with Ad-IkappaBalphaM, apoptosis rate was (31.1 +/- 2.5)%, being still higher than that of cells infected with Ad-IkappaBalpha but not treated with As(2)O(3) (20.7 +/- 2.1)% and these neither infected nor treated (13.0 +/- 1.7)%, P < 0.01. Therefore, infection with Ad-IkappaBalphaM can significantly increase the apoptosis induced by As(2)O(3).

CONCLUSIONS

Gastric carcinoma cells treated with As(2)O(3) show activity of NF-kappaB. It is indicated that the activity of NF-kappaB may be the mechanism of the antagonism of gastric carcinoma cells against the apoptosis induced by As(2)O(3). Infection with Ad-IkappaBalphaM can effectively inhibit the activation of NF-kappaB in gastric carcinoma cells and increase the cell apoptosis induced by As(2)O(3).