Hayashi T, Matesic D F, Nomata K, Kang K S, Chang C C, Trosko J E
Department of Pediatrics/Human Development, Institute of Environmental Toxicology, Michigan State University, East Lansing 48824, USA.
Cancer Lett. 1997 Jan 15;112(1):103-11. doi: 10.1016/S0304-3835(96)04553-3.
The effect of linoleic acid (LA) on gap-junction permeability, connexin 43 mRNA level, protein level, and phosphorylation, and the numbers of gap-junctional membrane plaques were studied in the rat liver epithelial cell line WB-F344 to determine whether changes in these parameters correlated with the enhanced cell growth and the inhibition of gap-junction function. When cultured in a medium with low serum (1%), these cells exhibited a slower growth rate than in the high serum medium (7%). Addition of linoleic acid (0.01-3 mg/ml) to the low serum medium increased the growth rate and inhibited gap junctional intercellular communication (GJIC) in a dose-dependent manner. In a comparison of short-term and long-term treatments with LA, GJIC in short-term treated (1 h) WB cells was inhibited at 3 mg/ml LA but readily recovered by washing and removing LA from cells, whereas GJIC in long-term treated (6 days) WB cells did not recover by washing and removing LA from WB cells. Western blot analysis of connexin 43 showed that a short-term incubation with linoleic acid increased the relative amount of unphosphorylated connexin 43 protein, but a long-term incubation with linoleic acid decreased the amount of unphosphorylated connexin 43 protein and increased the relative amount of hyperphosphorylated connexin 43 protein. Connexin 43 and p53 mRNA levels decreased in a time- and dose-dependent manner in linoleic acid-treated cells. These results suggest that growth stimulation and gap junctional intercellular communication inhibition of rat liver epithelial cells by linoleic acid may be mediated in part through modulation of p53 expression and function.
在大鼠肝上皮细胞系WB-F344中研究了亚油酸（LA）对缝隙连接通透性、连接蛋白43 mRNA水平、蛋白水平、磷酸化以及缝隙连接膜斑数量的影响，以确定这些参数的变化是否与细胞生长增强和缝隙连接功能抑制相关。当在低血清（1%）培养基中培养时，这些细胞的生长速率比在高血清培养基（7%）中慢。向低血清培养基中添加亚油酸（0.01 - 3 mg/ml）可提高生长速率，并以剂量依赖的方式抑制缝隙连接细胞间通讯（GJIC）。在亚油酸短期和长期处理的比较中，短期处理（1小时）的WB细胞在3 mg/ml亚油酸处理下GJIC受到抑制，但通过洗涤并从细胞中去除亚油酸后可迅速恢复，而长期处理（6天）的WB细胞经洗涤并去除亚油酸后GJIC未恢复。连接蛋白43的蛋白质印迹分析表明，亚油酸短期孵育增加了未磷酸化连接蛋白43的相对量，但亚油酸长期孵育降低了未磷酸化连接蛋白43的量，并增加了过度磷酸化连接蛋白43的相对量。在亚油酸处理的细胞中，连接蛋白43和p53 mRNA水平呈时间和剂量依赖性下降。这些结果表明，亚油酸对大鼠肝上皮细胞的生长刺激和缝隙连接细胞间通讯抑制可能部分通过调节p53的表达和功能介导。
