nm23-H_1基因转染能上调人肺癌细胞株L9981中GSK-3β激酶活性

Transfection of tumor metastasis suppressor gene nm23-H1 can up-regulate the activity of GSK-3β in human high-metastasis large cell lung cancer cell line L9981

目的 探讨转移抑制基因nm2 3 H1对人高转移大细胞肺癌细胞株L9981中Wnt信号传导激酶GSK 3 β的表达量和活性的影响 ,为全面阐明nm2 3 H1基因调控肺癌转移相关信号传导通路的分子机制提供实验依据。方法 将稳定转染nm 2 3 H1基因的人高转移大细胞肺癌细胞株L9981 nm2 3 H1、原代细胞株L9981和空载体转染细胞株L9981 pLXSN培养传代 ,应用Westernblot分别检测应用 2 0mmol/LLiCl处理前后三个肺癌细胞株胞浆、胞核中GSK 3 β的表达水平 ,应用免疫共沉淀同位素闪烁计数法测定上述肺癌细胞株胞浆和胞核中的GSK 3 β激酶活性。 结果 ( 1)L9981 nm2 3 H1胞浆和胞核中GSK 3 β蛋白表达量分别为( 63 41± 5 41)和 ( 4 3 5 6± 490 )IOD ,L9981 pLXSN分别为 ( 3 613± 3 83 )和 ( 70 5± 75 )IOD ,L9981分别为 ( 373 6± 2 98)和 ( 65 7± 5 7)IOD。三个细胞株间胞浆和胞核中GSK 3 β表达量均有非常显著差异 (P <0 .0 1) ;两两比较 :L9981 nm2 3 H1胞浆和胞核GSK 3 β表达水平均显著高于L9981 pLXSN和L9981(P <0 .0 1) ,而后两者之间比较均无显著性差异 (P >0 .0 5 )。 ( 2 )L9981 nm2 3 H1胞浆和胞核GSK 3 β激酶活性分别为 ( 2 895 5±2 5 0 9)和 ( 92 47± 92 4)CPM ,L9981 pLXSN分别为 ( 112 41±

Objective To investigate the influence of tumor metastasis suppressor gene nm23-H1 on the activity of glycogen synthase kinase 3β (GSK-3β) in human high-metastasis large cell lung cancer cell line L9981. Methods The levels of GSK-3β expression in cytoplasm and nucleus were determined with anti- GSK-3β antibody in human high-metastasis large cell lung cancer cell line L9981 (cell line with nm23-H1 gene deletion), L9981-nm23-H1 (cell line with nm23-H1 transfected) and L9981-pLXSN (cell line with vector transfected) by Western blot method. The activity of GSK-3β among those three cell lines was detected by immunoprecipitation and analysed by a radioactive isotope scintillation counter before and after treating with 20 mmol/L LiCl. Results (1) The expression indensity of GSK-3β of cytoplasm and nucleus was (6 341±541) and (4 356±490) IOD in L9981-nm23-H1, (3 613±383) and (705±75) IOD in L9981-pLXSN, and (3 736±298) and (675±57) IOD in L9981, respectively. A high significance in GSK-3β expressive indensity of both cytoplasm and nucleus existed among L9981-nm23-H1, L9981-pLXSN and L9981 (P<0.01); Multiple comparison: A highly significant difference was observed when L9981-nm23-H1 was compared with L9981-pLXSN or L9981 (P<0.01), but no significant difference was observed between L9981-pLXSN and L9981 (P>0.05). (2) The GSK-3β activity of cytoplasm and nucleus was (28 955±2 509) and (9 247±924) CPM in L9981-nm23-H1, (11 241±1 495) and (1 492±176) CPM in L9981-pLXSN, and (12 505±1 469) and (1 763±125) CPM in L9981, respectively. A highly significant difference in GSK-3β activity of both cytoplasm and nucleus existed among L9981-nm23-H1, L9981-pLXSN and L9981 (P<0.01); Multiple comparison: the GSK-3β activity in L9981-nm23-H1 was significantly higher than that in L9981-pLXSN and L9981 (P< 0.01), but no significant difference was observed between the L9981-pLXSN and L9981 (P>0.05). (3) After treatment with 20 mmol/L LiCl, the expressive indensity of GSK-3β of cytoplasm and nucleus was (4 718±549) and (3 823±350) IOD in L9981-nm23-H1, (2 030±155) and (217±15) IOD in L9981-pLXSN, and (2 164±151) and (224±19) IOD in L9981, respectively. No significant difference in GSK-3β expressive indensity existed between before and after treatment with LiCl in L9981-nm23-H1 (P> 0.05). However, the GSK-3β expressive indensity in cytoplasm and nucleus before treatment was remarkably higher than those after treatment in both L9981-pLXSN and L9981 (P<0.05). (4) After treatment with 20 mmol/L LiCl, the GSK-3β activity in cytoplasm and nucleus was (11 099±1 112) and (3 748±215) CPM in L9981-nm23-H1, (4 447±430) and (1067±159) CPM in L9981, and (4 435±427) and (909±156) CPM in L9981-pLXSN, respectively. The GSK-3β activity both in cytoplasm and nucleus after treatment with LiCl was remarkably lower than that before treatment in L9981-nm23-H1, L9981-pLXSN and L9981 (P<0.01 or P<0.05). Conclusion (1) Transfection of nm23-H1 gene can significantly up-regulate the expression level and activity of GSK-3β in human high-metastasis large cell lung cancer cell line L9981; (2) LiCl can remarkably suppress the upregulation effects of nm23-H1 gene on GSK-3β activity in L9981 cell line; (3) The effects of nm23-H1 gene on suppressing the signal transduction of Wnt pathway might be carried out through upregulating GSK-3β expression and activity in human high-metastasis large cell lung cancer cell line L9981.