Rivedal E, Mollerup S, Haugen A, Vikhamar G
Laboratory for Environmental and Occupational Cancer, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo.
Carcinogenesis. 1996 Nov;17(11):2321-8. doi: 10.1093/carcin/17.11.2321.
Modulation of gap junctional intercellular communication (GJIC) was studied in a multistep model of human renal epithelial carcinogenesis. We report that the majority of primary human kidney epithelial cells (NHKE) grown from fetal kidney explants did not communicate through gap junctions. Communication could, however, be observed within a subpopulation of the cells. Ni(II)-immortalized cells (IHKE) showed GJIC at a level of 10-20 communicating cells, but with heterogeneous regions on the dish, with regard to both communication and distribution of connexin43. The heterogeneity was less pronounced in a ras-transfected tumourigenic cell line (THKE), which also showed communication of approximately 10-20 dye-coupled cells. Communication within the IHKE sub-clone K7 decreased from 55 dye-coupled cells communicating on day 1 after seeding to approximately 13 in cells grown for 4 days. Daily change of growth medium reduced the decrease in GJIC. EGF enhanced communication following a lag period which depended on days in culture. The largest increase in GJIC was observed in 2-day-old cultures, where the number of communicating cells in some experiments increased from approximately 45 to 130 dye-coupled cells 4 h following change to medium with EGF. The induction was concentration dependent and communication was enhanced gradually between 2 and 7 h after exposure to EGF. A 15 min pulse of EGF was sufficient to induce the GJIC increase if the total incubation period was unchanged. Cycloheximide completely blocked the EGF-induced enhancement of communication, while actinomycin D had no effect. EGF exposure resulted in an increase in the cellular level of connexin43 protein in parallel with the enhancement in communication. Together, these results indicate that the EGF-induced enhancement of GJIC in human kidney epithelial cells was mediated through translational control of connexin43 expression.
在人肾上皮细胞癌变的多步骤模型中研究了间隙连接细胞间通讯（GJIC）的调节。我们报告称，从胎儿肾外植体生长而来的大多数原代人肾上皮细胞（NHKE）不通过间隙连接进行通讯。然而，在细胞亚群中可以观察到通讯现象。镍（II）永生化细胞（IHKE）在10 - 20个通讯细胞的水平上显示出GJIC，但在培养皿上存在异质性区域，在连接蛋白43的通讯和分布方面均如此。在转染了ras的致瘤细胞系（THKE）中，这种异质性不太明显，该细胞系也显示出约10 - 20个染料偶联细胞的通讯。IHKE亚克隆K7内的通讯从接种后第1天的55个染料偶联通讯细胞减少到生长4天的细胞中的约13个。每天更换生长培养基可减少GJIC的下降。表皮生长因子（EGF）在一段取决于培养天数的延迟期后增强通讯。在2日龄培养物中观察到GJIC的最大增加，在一些实验中，更换为含EGF的培养基4小时后，通讯细胞的数量从约45个增加到130个染料偶联细胞。这种诱导是浓度依赖性的，并且在暴露于EGF后2至7小时之间通讯逐渐增强。如果总孵育期不变，15分钟的EGF脉冲足以诱导GJIC增加。放线菌酮完全阻断了EGF诱导的通讯增强，而放线菌素D则没有作用。EGF暴露导致连接蛋白43蛋白的细胞水平增加，同时通讯增强。总之，这些结果表明，EGF诱导的人肾上皮细胞GJIC增强是通过连接蛋白43表达的翻译控制介导的。
