Watari H
Department of Obstetrics and Gynecology, Hokkaido University School of Medicine, Sapporo, Japan.
Hokkaido Igaku Zasshi. 1995 Jul;70(4):623-34.
Human choriocarcinoma cell lines, preserving many biological properties of normal trophoblasts, are good models for investigating of trophoblastic cell biology. Most of these cells express various oncogenes, which might have essential roles for biological characteristics of choriocarcinoma cells. Of these oncogenes, ras gene family has been known to play the key roles in cell growth, transformation and differentiation. In order to investigate the roles of ras genes on various unique characters of trophoblasts, the author transfected the viral H- or K-ras oncogene into a human choriocarcinoma cell line, CC1, and established choriocarcinoma cell lines acquired up-regulated activity of ras genes. v-ras-expressing clones exhibited almost the same growth capacities as control clones, but only v-H-ras clones formed the many fluid-filled hemispherical "domes" in a cell layer. Microscopic observation of these domes clarified that the accumulation of fluid between cell layer and the surface of culture dish has resulted in dome formation, which is characteristic of the polarized epithelial cells and represents an in vitro morphologic expression of vectorial transport function. Since these clones exhibited higher Na(+)-K(+)-ATPase activity than other clones and dome formation was inhibited with the treatment of ouabain, a specific inhibitor of Na(+)-K(+)-ATPase, dome formation may be due to the augmentation of the vectorial fluid transport driven by Na(+)-K(+)-ATPase. In addition, the expression of human chorionic gonadotropin (hCG) beta was examined to investigate the effects of ras genes on peptide hormone production which is one of the differentiated functions of trophoblasts. v-K-ras-expressing clones secreted significantly more hCG than controls, while v-H-ras did not seem to affect hCG-producing activity. These results obtained in this study indicate that H-ras gene may facilitate the vectorial transcellular fluid transport from maternal site to fetus, while K-ras gene is associated with some endocrine functions such as hCG production in trophoblasts.
人绒毛膜癌细胞系保留了许多正常滋养层细胞的生物学特性，是研究滋养层细胞生物学的良好模型。这些细胞中的大多数表达各种癌基因，这些癌基因可能对绒毛膜癌细胞的生物学特性起着至关重要的作用。在这些癌基因中，ras基因家族已知在细胞生长、转化和分化中起关键作用。为了研究ras基因对滋养层细胞各种独特特征的作用，作者将病毒H-或K-ras癌基因转染到人绒毛膜癌细胞系CC1中，并建立了ras基因活性上调的绒毛膜癌细胞系。表达v-ras的克隆表现出与对照克隆几乎相同的生长能力，但只有表达v-H-ras的克隆在细胞层中形成了许多充满液体的半球形“圆顶”。对这些圆顶的显微镜观察表明，细胞层与培养皿表面之间液体的积聚导致了圆顶的形成，这是极化上皮细胞的特征，代表了载体转运功能的体外形态学表达。由于这些克隆比其他克隆表现出更高的Na(+)-K(+)-ATP酶活性，并且用Na(+)-K(+)-ATP酶的特异性抑制剂哇巴因处理可抑制圆顶的形成，因此圆顶的形成可能是由于Na(+)-K(+)-ATP酶驱动的载体液体转运增强所致。此外，检测了人绒毛膜促性腺激素（hCG）β的表达，以研究ras基因对作为滋养层细胞分化功能之一的肽激素产生的影响。表达v-K-ras的克隆分泌的hCG明显多于对照，而v-H-ras似乎不影响hCG的产生活性。本研究获得的这些结果表明，H-ras基因可能促进从母体部位到胎儿的载体跨细胞液体转运，而K-ras基因与滋养层细胞中的一些内分泌功能如hCG产生有关。
