Marushige K, Marushige Y
Department of Pathology, Michigan State University, East Lansing, Michigan 48824, USA.
Anticancer Res. 1998 Jan-Feb;18(1A):295-300.
Exposure of trigeminal neurinoma 476-16 cells to C2-ceramide in a serum-deprived medium induces cell rounding followed by cell death characterized by cytoplasmic shrinkage and nuclear condensation. The induction of cell rounding and death occurs in proliferating cells but not in essentially quiescent cells of confluent cultures. Trypan blue-unpermeable round cells formed as a result of ceramide treatment undergo apoptosis without ceramide in a serum-containing medium, suggesting that they are irreversibly committed to cell death. The induction of cell rounding by ceramide is inhibited by low doses of the protein-tyrosine phosphatase inhibitors, orthovanadate and pervandate, and stimulated by high doses of pervanadate. The inhibition of protein-tyrosine phosphatases interfers the induction of cell death by ceramide. The protein-serine/threonine phosphatase inhibitor calyculin A induces cell rounding in proliferating cells. This cell rounding does not lead to cell death, thus calyculin A inhibits the induction of cell death by ceramide. While orthovanadate inhibits the induction of cell rounding by calyculin A, the latter is potentiated by ceramide. A combination of ceramide and calyculin A induces cell rounding and cell death in confluent cultures. These results demonstrate that modulation of phosphorylation of the serine/threonine and tyrosine of cellular proteins is intimately involved in the process of cell rounding and apoptosis in anchorage-dependent cells.
在无血清培养基中，将三叉神经鞘瘤476 - 16细胞暴露于C2 - 神经酰胺会导致细胞变圆，随后细胞死亡，其特征为细胞质收缩和核浓缩。细胞变圆和死亡的诱导发生在增殖细胞中，但在汇合培养的基本静止细胞中则不会发生。经神经酰胺处理形成的台盼蓝拒染圆形细胞在含血清培养基中无需神经酰胺即可发生凋亡，这表明它们不可逆地走向细胞死亡。低剂量的蛋白质酪氨酸磷酸酶抑制剂原钒酸盐和过钒酸盐可抑制神经酰胺诱导的细胞变圆，而高剂量的过钒酸盐则会促进细胞变圆。蛋白质酪氨酸磷酸酶的抑制会干扰神经酰胺诱导的细胞死亡。蛋白质丝氨酸/苏氨酸磷酸酶抑制剂花萼海绵诱癌素A可诱导增殖细胞变圆。这种细胞变圆不会导致细胞死亡，因此花萼海绵诱癌素A可抑制神经酰胺诱导的细胞死亡。虽然原钒酸盐可抑制花萼海绵诱癌素A诱导的细胞变圆，但后者会被神经酰胺增强。神经酰胺和花萼海绵诱癌素A的组合可诱导汇合培养细胞变圆和细胞死亡。这些结果表明，细胞蛋白质丝氨酸/苏氨酸和酪氨酸磷酸化的调节密切参与了贴壁依赖性细胞的细胞变圆和凋亡过程。
