Cesen-Cummings K, Warner K A, Ruch R J
Department of Pathology, Medical College of Ohio, Toledo 43614, USA.
Anticancer Res. 1998 Nov-Dec;18(6A):4343-6.
Protein kinase C (PKC) activity is increased and gap junctional intercellular communication (GJIC) is decreased frequently in Ras-transformed cells. We investigated the roles of Ras and PKC in the deficient gap junctional intercellular communication (GJIC) of K-ras-transformed E9 mouse lung carcinoma cells.
GJIC was measured by fluorescent dye microinjection. Ras activity was blocked with lovastatin or a K-ras antisense oligonucleotide. PKC activity was inhibited with GF 109203X or apigenin or was downregulated by overnight treatment with 12-O-tetradecanoylphorbol-13-acetate. The content and phosphorylation of the gap junction protein, connexin43 (Cx43), was assessed by Western blot.
E9 cell GJIC was increased two-three fold by lovastatin, the K-ras antisense oligonucleotide, and PKC inhibition/downregulation. Cx43 content and phosphorylation were unchanged, however.
Oncogenic Ras blocks GJIC in E9 cells through a PKC-dependent mechanism, but this does not directly involve Cx43 expression or phosphorylation.
在Ras转化的细胞中，蛋白激酶C（PKC）活性增加，而间隙连接细胞间通讯（GJIC）经常减少。我们研究了Ras和PKC在K-ras转化的E9小鼠肺癌细胞间隙连接细胞间通讯缺陷中的作用。
通过荧光染料显微注射测量GJIC。用洛伐他汀或K-ras反义寡核苷酸阻断Ras活性。用GF 109203X或芹菜素抑制PKC活性，或用12-O-十四烷酰佛波醇-13-乙酸酯过夜处理下调PKC活性。通过蛋白质印迹法评估间隙连接蛋白连接蛋白43（Cx43）的含量和磷酸化。
洛伐他汀、K-ras反义寡核苷酸和PKC抑制/下调使E9细胞GJIC增加两到三倍。然而，Cx43的含量和磷酸化没有变化。
致癌性Ras通过PKC依赖性机制阻断E9细胞中的GJIC，但这并不直接涉及Cx43的表达或磷酸化。
