OBJECTIVETo investigate the inhibitory effect of photodynamic therapy (PDT) in combination with paclitaxel (PCT) on proliferation in esophageal carcinoma Eca-109 cells line.

METHODSEca-109 cells were treated with PCT alone, HPD alone at different doses, or their combinations. For the combined treatments, the cells were exposed to PCT for 12 h followed by incubation with HPD at high, middle or low concentrations for 4 h. PDT was then performed on these treated cells and fluorescence microscopic observation was made before and after PDT. The cell survival was measured by MTT assay, and the cell apoptosis rate analyzed by flow cytometry after a 24-h cell incubation following PDT.

RESULTSThe fluorescence excitation of the cells was weakened after PDT. Combined treatments resulted in significantly lowered cell survival rate and increased cell apoptosis rates as compared to those of the control cells and the cells treated with PCT alone and low-dose HPD (P<0.01). Significant differences were also noted among the cells exposed to HPD at different concentrations (P<0.05).

CONCLUSIONPDT combined with PCT have significant synergetic effects in inhibiting the proliferation of human esophageal carcinoma cells and inducing their apoptosis in vitro.