In vitro arsenic trioxide induces apoptosis in T cells of asthmatic patients by a Bcl-2 related mechanism.
This study examined the effects of arsenic trioxide on apoptosis and interleukin-4 release in T cells of asthmatic patients in vitro and investigated the role of Bcl-2 in the active mechanism. T cells were isolated from asthmatic patients (n = 21) and healthy controls (n = 20), and then treated with arsenic trioxide and dexamethasone. Cell apoptosis was measured using fluorescence microscopy, flow cytometry and a cytochrome c ELISA kit. Interleukin-4 levels in the serum and in supernatants from T cells were quantified by ELISA. Flow cytometric analysis and immunofluorescence studies were performed to determine Bcl-2 expression. T cells of the asthmatic patients (i. e. without treatment) exhibited decelerated spontaneous apoptosis after 24 h incubation in vitro when compared to T cells of the healthy controls. With dexamethasone treatment, an increase in apoptosis of T cells was not significantly different between both groups, irrespective of the method used. Arsenic trioxide treatment, however, significantly increased the apoptosis of T cells of the asthmatic group and showed a slight effect on the control group. In asthmatic patients, elevated levels of interleukin-4 and up-regulated Bcl-2 expression were detected. Moreover, in vitro, T cells of asthmatic patients spontaneously released more interleukin-4 and exhibited more Bcl-2 expression than T cells from the control group. Arsenic trioxide treatment significantly decreased interleukin-4 release and down-regulated Bcl-2 expression in asthmatic patients, while it only slightly affected healthy controls. Dexamethasone treatment decreased interleukin-4 release in both groups examined. It did not significantly influence Bcl-2 expression. These results suggest that arsenic trioxide induces T cell apoptosis and decreases interleukin-4 release in T cells of asthmatic patients in vitro and that down-regulation of Bcl-2 expression may be an important mechanism.
Qin
Dong-Yun
DY
Department of Pharmacology, Guangdong Medical College, Zhanjiang 524023, China.
Huang
Ren
R
Wu
Tie
T
D000328:Adult; D018927:Anti-Asthmatic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D001249:Asthma / Q000378:metabolism / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D015847:Interleukin-4 / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D010087:Oxides / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology*
D018927:Anti-Asthmatic Agents; D001152:Arsenicals; D010087:Oxides; D019253:Proto-Oncogene Proteins c-bcl-2; D015847:Interleukin-4; D000077237:Arsenic Trioxide