The effect of cytochalasin D on ECa109 esophageal sqamous cancer cells was studied. When (ECa109) cells were treated with 0.2～1?g/ml cytochalasin D, small epithelial cells with a few microvilli could be seen. After incubation with 0.5?g/ml of cytochalasin D for one or three days, irregular buds containing endoplasmic reticulum, mitochondria and Golgi complexes grew out from the surface of the epithelial cells. The target-shaped mitochondria, the "confronting cisterna" of the endoplasmic reticulum, ring-shaped endoplasmic reticulum and disaggregated Golgi complexes were appeared in the cytoplasm. After treatment with 0.2?g/ml of cytochalasin D for one day multinucleated epithelial cells appeared. There were 2～6 nuclei, with different in size and shape. Some nuclei were fully enclosed with neuclear envelops and the others only partically. Mitotic cells could be seen too. The effect of cytochalasin D on the structure and function of the epithelial cells and the different roles played by the actin and tubulin in keeping the normal function of the cytoskeleton system of the ECa109 cells were discussed.

The surface and ultrastructure of the interphase and mitotic ECa 109 esophagealcancer epithelial cells were investigated by means of scanning and transmission electronmicroscopes.The electron microscopies revealed that cells grown in culture haddifferent external appearances during the different phases of cell cycle.At interphase,the cells were flattened and irregular in shapes,the surface were covered with microvilli.Centrosome,tonofilaments,mitochondria could be found in the cytoplasm.The largeand irregular shaped nucleus was located at the centre.It had one or more nucleoli.During the mitotic phase the cells were spherical and they became first cylindricaland then dumb-bell in shapes,Finally,they divided into daughter cells.There werespindle area and non-spindle area in the cell.The former was at the center of thecell and the latter occupied the outer part of the cell.In the spindle area,thechromatin clumped and the centrioles were prominent,the chromosomes were close tothe equatorial plate.The spindle tubules were seen radiating from the centriole andattached to chromosome at the kinetochore,and among them there were a fewmitochondria.In the non-spindle area,the cell organelles could be observed but fewGolgi complex present.It was shown that many changes of the cells could be foundduring mitosis,and that the spindle-fibers,filopodia,rod-like elements and the cellmembranes might play an important role during mitosis.