Requirement of the MAP kinase cascade for cell cycle progression and differentiation of human intestinal cells
Requirement of the MAP kinase cascade for cell cycle progression and differentiation of human intestinal cells
复制标题
DOI：
10.1152/ajpgi.1999.277.3.g631
复制
发表时间：
1999-09-01
影响因子：
4.5
通讯作者：
Rivard, N
中科院分区：
文献类型：
--
作者：
Aliaga, JC;Deschênes, C;Rivard, N
负责细胞周期停滞和沿着肠轴建立分化细胞的细胞内信号传导途径仍然很大程度上未知。本研究分析了p42/p44丝裂原激活蛋白激酶(MAPK)在人肠道细胞增殖和分化过程中的调控作用。在 Caco-2/15 细胞中进行了体外研究，Caco-2/15 细胞是一种自发分化为肠上皮细胞表型的人类结肠癌细胞系。通过间接免疫荧光对人胎儿肠上皮的低温切片进行体内研究。我们发现，PD-98059 化合物或 MAPK 磷酸酶-1 的异位表达对 p42/p44 MAPK 信号传导的抑制会强烈减弱 Caco-2/15 细胞中 E2F 依赖性转录活性。一旦 Caco-2/15 细胞达到汇合，p42/p44 MAPK 活性就会急剧下降。然而，在分化的 Caco-2/15 细胞中检测到显着水平的活化 p42 MAPK。在分化过程中添加 PD-98059 会干扰 p42 MAPK 的持续激活和蔗糖酶-异麦芽糖酶表达。尽管p42/p44 MAPK在绒毛尖端和隐窝细胞中均表达，但在未分化的隐窝细胞中检测到它们的磷酸化和活性形式。我们的结果表明，升高的p42/p44 MAPK 活性刺激肠细胞的细胞增殖，而持续低水平的MAPK 活性与G(1) 阻滞和蔗糖酶-异麦芽酶表达增加相关。
The intracellular signaling pathways responsible for cell cycle arrest and establishment of differentiated cells along the gut axis remain largely unknown. In the present study we analyzed the regulation of p42/p44 mitogen-activated protein kinase (MAPK) in the process of proliferation and differentiation of human intestinal cells. In vitro studies were done in Caco-2/15 cells, a human colon cancer cell line that spontaneously differentiates into an enterocyte phenotype. In vivo studies were performed on cryostat sections of human fetal intestinal epithelium by indirect immunofluorescence. We found that inhibition of the p42/p44 MAPK signaling by the PD-98059 compound or by ectopic expression of the MAPK phosphatase-l strongly attenuated E2F-dependent transcriptional activity in Caco-2/15 cells. p42/p44 MAPK activities dramatically decreased as soon as Caco-2/15 cells reached confluence. However, significant levels of activated p42 MAPK were detected in differentiated Caco-2/15 cells. Addition of PD-98059 during differentiation interfered with sustained activation of p42 MAPK and sucrase-isomaltase expression. Although p42/p44 MAPKs were expressed in both the villus tip and crypt cells, their phosphorylated and active forms were detected in the undifferentiated crypt cells. Our results indicate that elevated p42/p44 MAPK activities stimulate cell proliferation of intestinal cells, whereas low sustained levels of MAPK activities correlated with G(1) arrest and increased expression of sucrase-isomaltase.