Abstract: OBJECTIVE: To study the effects and mechanisms of manumycin on the proliferation of human esophageal carcinoma cell line Eca109. METHODS：Eca109 cells were treated with different concentrations of manumycin (10，20，40，80，120 μmol/L) for 24，48 and 72 h，and cytotoxic effects of manumycin on the proliferation of Eca109 cells was measured by MTT assay. Morphological changes of Eca109 cells were observed by Giemsa staining and transmission electron microscopy. Distribution of cell cycle and cell apoptosis were examined by flow cytometry assay. RESULTS：Compared with control group，manumycin significantly inhibited the proliferation of Eca109 cells (P<0.05). Giemsa staining and electron microscopy showed that the Eca109 cells demonstrated some ultra-micro structural changes of apoptosis. Flow cytometry assay showed that the cells in G2/M stage were significantly increased with the increasing concentration of manumycin. After treatment with (10，20，40，80，120 μmol/L) manumycin for 48 h， the apoptotic percentage were 4.520%±1.035%，14.490%±1.707%，28.883%±4.299%，35.107%±2.276%， 47.940% ±8.126%，respectively.

Key words: manumycin, esophageal carcinoma, proliferation, apoptosis