A study on arsenic trioxide inhibiting in vitro growth of human colon cancer cells

Objective To observe the effect of arsenic trioxide on the proliferation of human colon cancer cells HT-29 in vitro and investigate its mechanism. Methods HT-29 cells (a human colon cancer cell line) were treated with arsenic trioxide in different concentrations. The inhibition on the proliferation of HT-29 cells was estimated by MTT-assay. Morphological changes were observed under light microscope and electron microscope. Apoptosis and autophagy were analyzed by flow cytometer and confocal microscopy. Results When treated with 4.0μmol/L arsenic trioxide for 72h, the proliferation of HT-29 cells was obviously inhibited and the cell underwent conspicuous apoptosis. The inhibition on the proliferation depended on the exposure time and dose. The cells showed morphological changes at the early stage of apoptosis under the light microscope: the shrunk and round cells; condensed cytoplasma and pycnosis nucleus and autophasosomes could be found under the transmission electron microscope. The rate of the apoptotic cells was 25% after intervention with low concentration of arsenic trioxide (4.0μmol/L) for 72h. Conclusion Arsenic trioxide could significantly inhibit the proliferation of HT-29 cells, and the proliferation inhibition is closely related to cell apoptosis and autophagy.