氧化砷诱导食管癌细胞凋亡线粒体形态改变

通过研究食管癌细胞株ＳＨＥＥＣＩ细胞凋亡早期线粒体的形态改变和ｂｃｌ－２ｂａｘ的表达,以了解三氧化二砷（Ａｓ２Ｏ３）作用于食管癌细胞的机制。方法食管癌细胞株ＳＨＥＥＣ１用１、２、３μｍｏｌ／Ｌ Ａｓ２Ｏ３作用２、４、６、１２、２４ｈ。用Ａｎｎｅｘｉｎ－Ｖ荧光探针,流式细胞仪和ＤＮＡ组方图检早期凋亡细胞;光镜和电镜检测凋亡细胞的形态学改变;用罗达明（Ｒｈｏｄａｍｉｎ１２３）荧光探针检查活细胞线粒体的

Morphological changes of mitochondria in apoptosis of esophageal carcinoma cells induced by As(2)O(3)

OBJECTIVE: In order to make clear how As(2)O(3) targets the cells of esophageal carcinoma, the morphology of mitochondria and expression of bcl-2/bax were selected to study the SHEEC1 cell line during early apoptosis. METHODS: The esophageal carcinoma cell line SHEEC1 was treated by As(2)O(3) with concentrations of 1, 2 and 3 micromol/L for the periods of 2, 4, 6, 12 and 24 h. Annexin-V-Fluorescein and DNA histogram were used to detect the early apoptotic cells by flow cytometry. The morphologic changes of the apoptotic cells were examined by means of light and electron microscopy. Changes in mitochondria of living cells were detected with Rhodamin 123 fluorescent probe by fluorescent microscopy. The expression of bcl-2 and bax in floating cells were determined by immunohistochemical procedures. RESULTS: Typical apoptotic morphological changes were found in SHEEC1 at 24 h after As(2)O(3) treatment. Cells in the early stage of apoptosis were detected by Annexin-V labeled at 4 h. The ultrastructural alterations of mitochondria were found as following: within 4 h after administrating As(2)O(3), mitochondrial hyperplasia with small electron-dense materials in its matrix was the earliest manifestation of cell injury. At 6 h progressive mitochondrial swelling lead to balloon-like appearance and its outer membrane disrupted at 12 h. In all groups, down regulated expression of bcl-2 and over expression of bax were always found in damaged cells. CONCLUSION: In the SHEEC1 cell line morphological changes of mitochondria are the early events in apoptosis induced by As(2)O(3) and apoptosis is closely related to over expression of bax and down-regulating expression of bcl-2. It is possible that As(2)O(3) is a mitochondriotoxic anticancer agent for esophageal carcinoma.