Rae R S, Mehta P P, Chang C C, Trosko J E, Ruch R J
Department of Pathology, Medical College of Ohio, Toledo 43699, USA.
Mol Carcinog. 1998 Jun;22(2):120-7. doi: 10.1002/(sici)1098-2744(199806)22:2<120::aid-mc7>3.0.co;2-q.
Gap-junctional intercellular communication (GJIC) is involved in cellular growth control and is often reduced in neoplastic cells. In this study, four GJIC-deficient rat liver epithelial cell lines (WB-aB1, WB-bA2, WB-cD6, and WB-dA2) were examined for altered growth and tumorigenicity in comparison with their GJIC-competent parental cell line, WB-F344. WB-aB1 cells were also forced to express connexin 32 (Cx32) by transduction with a Cx32 cDNA retroviral expression vector to help determine whether the restoration of GJIC could reverse their neoplastic phenotype. WB-aB1 and WB-bA2 cells had faster population doubling times (PDTs) and higher saturation densities (SDs) than did WB-F344 cells. In contrast, the growth of WB-cD6 and WB-dA2 cells was not significantly different from that of WB-F344 cells. WB-aB1 and WB-bA2 cells formed tumors in male F344 rats, but WB-cD6 and WB-dA2 cells did not. After transduction of WB-aB1 cells with Cx32, four stable clones (WB-a/32-3, -8, -9, and -10) were isolated that had GJIC levels of 5.2%, 44.5%, 69.8%, and 90.5%, respectively. The growth of poorly coupled clones 3 and 8 was similar to that of parental WB-aB1 cells, but the growth of well-coupled clones 9 and 10 was similar to that of WB-F344 cells. The tumorigenicity of WB-a/32-9 and WB-a/32-10 cells was also significantly lower than that of WB-aB1 cells. Our results suggest that reduced GJIC contributes to neoplastic transformation of WB cells, that additional changes are necessary, and that restoration of GJIC by forced Cx32 protein expression can suppress the neoplastic phenotype of these cells.
间隙连接细胞间通讯（GJIC）参与细胞生长控制，在肿瘤细胞中常被削弱。在本研究中，检测了四种GJIC缺陷的大鼠肝上皮细胞系（WB-aB1、WB-bA2、WB-cD6和WB-dA2）与其具有GJIC功能的亲代细胞系WB-F344相比，其生长和致瘤性的改变。还通过用Cx32 cDNA逆转录病毒表达载体转导，使WB-aB1细胞强制表达连接蛋白32（Cx32），以帮助确定GJIC的恢复是否能逆转其肿瘤表型。WB-aB1和WB-bA2细胞比WB-F344细胞具有更快的群体倍增时间（PDT）和更高的饱和密度（SD）。相比之下，WB-cD6和WB-dA2细胞的生长与WB-F344细胞无显著差异。WB-aB1和WB-bA2细胞在雄性F344大鼠中形成肿瘤，但WB-cD6和WB-dA2细胞则不能。用Cx32转导WB-aB1细胞后，分离出四个稳定克隆（WB-a/32-3、-8、-9和-10），其GJIC水平分别为5.2%、44.5%、69.8%和90.5%。偶联较差的克隆3和8的生长与亲代WB-aB1细胞相似，但偶联良好的克隆9和10的生长与WB-F344细胞相似。WB-a/32-9和WB-a/32-10细胞的致瘤性也显著低于WB-aB1细胞。我们的结果表明，GJIC的降低有助于WB细胞发生肿瘤转化，还需要其他变化，并且通过强制表达Cx32蛋白恢复GJIC可以抑制这些细胞的肿瘤表型。
