腺苷三磷酸对人横纹肌肉瘤细胞系P21和c-myc蛋白表达的影响

为进一步研究腺苷三磷酸抑制癌细胞增殖诱导分化的作用机理，用ＡＴＰ作用于人横纹肌肉瘤单细胞克隆亚系ＲＤＬ６细胞，用免疫荧光细胞化学方法观察ＡＴＰ作用后的ＲＤＬ６细胞核内Ｐ＾２１蛋白表达增强，ｃ－ｍｙｃ蛋白表达降低，膜下胞质内微丝束－应力纤维组改善，粘着斑内的主要粘附蛋白－纽蛋白（ｖｉｎｃｕｌｉｎ）表达增强，正常小鼠成肌细胞Ｃ２Ｃ１２细胞核内Ｐ＾２１蛋白高表达，ｃ－ｍｙｃ蛋白不表达。结果表明：ＲＤＬ６

EFFECTS OF ATP ON THE EXPRESSION OF P 21 AND c myc PROTEINS IN HUMAN RHABDOMYOSARCOMA CELLS

We have reported that adenosine triphosphate (ATP) induced growth inhibition and cell differentiation in human rhabdomyosarcoma cells. To further investigate mechanisms involved in the reverse transformation of rhabdomyosarcoma cells, expression of P 21 and c myc proteins in a subclone RDL 6 originated from human rhabdomyosarcoma cell line, was studied by using immunofluorescence cytochemical methods. After treatment with ATP, increased nuclear P 21 protein immunofluorescence and reduced nuclear c myc product immunofluorescence was observed in RDL 6 cells. Increased number and organization of cytoplasmic actin stress fibers with vinculin immunofluorescence positive adhesion plaques at the termini of stress fibers were also observed. Normal myoblast C 2C 12 cells expressed intense P 21 but negative c myc while the untreated RDL 6 cells expressed weak P 21 but intense c myc in the nuclei.The above results strongly suggested that loss of P 21 and activation of c myc expression correlate with uncontrolled cell growth and aberrant differentiation in RDL 6 cells.Accordingly, it is indicated that increase of P 21 and reduction of c myc expression plays important roles in reverse transformation of phenotypes in RDL 6 cells.