OBJECTIVETo detect the expression of dopamine receptor D2 in different pulmonary carcinoma cells and investigate the effect of dopamine in inducing apoptosis of A549 cells.

METHODSWestern blotting and RT-PCR were employed to detect the expression of dopamine receptor D2 in different pulmonary carcinoma cells (95D, H460, GLC-82, A549 and H446 cells). The apoptosis of A549 cells after a 6-hour exposure to 0.02%, 0.04%, 0.08% and 0.1% dopamine was analyzed by flow cytometry. The apoptosis-inducing effect of dopamine in vivo was also tested by intratumoral injection of 1% dopamine in 2 BALB/c-nu mice bearing A549 tumor xenograft using flow cytometry.

RESULTSThe presence of dopamine receptor D2 expression was detected by Western blotting and RT-PCR in 95D, H460, GLC-82, A549 and H446 cells. Flow cytometry detected obvious apoptosis of A549 cells following dopamine exposure in vitro in positive correlation to dopamine concentration. In the tumor-bearing mice, dopamine also showed an obvious apoptosis-inducing effect on A549 cells.

CONCLUSIONDopamine receptor D2 exists extensively in different pulmonary carcinoma cells. Dopamine may promote the apoptosis of pulmonary carcinoma cells through dopamine receptor D2.