蛋白激酶C对大肠癌细胞间隙通讯和粘附分子表达的调节

Regulative effects of PKC on gap junction intercellular communication and expression of adhesion molecules in colon carcinoma HT-29 cell

目的:探讨蛋白激酶C(protein kinase C,PKC)对大肠癌HT-29细胞间隙通讯和粘附分子表达的调节作用。方法:采用激光共聚焦对细胞间隙通讯(GJIC)功能测定,用Western blot分析E-cadherin(E-cad)、laminin receptor(LnR)、α-catenin和β-catenin粘附分子表达,研究PKC激活剂佛波酯PMA和抑制剂staurosporine(SP)对HT-29细胞间隙通讯和粘附分子表达的调节作用。结果:GJIC功能测定提示,PMA可延滞GJIC功能恢复(P<0.05)。但SP和PMA共同作用细胞后,可使GJIC功能恢复明显增快,与PMA处理组比较,差异显著(P<0.05)。Western blot分析提示,HT-29细胞可高表达E-cad、LnR,而低表达α-catenin、β-catenin。100 nmol/L PMA可诱导细胞表达LnR增强,使E-cad表达下调,但对α-catenin、β-catenin表达无影响。而SP可拮抗PMA的作用,使LnR表达下降,E-cad表达增强,对α-catenin和β-catenin的表达作用亦无影响。结论:PMA和SP对细胞表达E-cad、LnR的作用可能受到PKC调控,PMA和SP调节HT-29细胞粘附的机制可能还涉及其影响了细胞的GJIC功能,可能与PMA和SP调控细胞E-cad表达机制有关。

Objective ：To evaluate the regulative effects of PKC on gap junction intercellular communication （GJIC） and expression of adhesion molecules in colon carcinoma HT - 29 cell. Methods： GJIC function of colon cancer HT - 29 cell was detected by confocal lasor scanning microscopy. Expressions of some adhesive molecules,such as E - cadherin （E - cad） ,laminin receptor （LnR） ,α - catenin and β - catenin in these cells were determined by Western blot. Regulative effects of PKC activator phorbol - 12 - myristate - 13 - acetate（PMA） and PKC inhibitor stauresporine （SP） on GJIC and expression of above adhesion molecules were investigated. Results ：The determination of GJIC function of HT - 29 cell indicated that its recovery rate decreased after PMA treatment （P 〈0.05 ）. However, the recovery rate of GJIC function increased significantly after treatment with SP plus PMA compared with that only treated with PMA （ P 〈0.05 ）. The findings of Western blot showed that in HT - 29 cell ,the expressions of E - cad and LnR were higher than α - catenin and β- catenin. 100 nmol/L PMA treatment for 4 h could induce LnR expression increasing and down regulate the E - cad expression,but it had no effects on α- catenin and β - catenin expression. SP could rivalry the effects of PMA by reducing the LnR expression and increasing E - cad expression although it also had no effects on α - catenin and β - catenin expression. Conclusion：The effects of PMA and SP on expressions of E - cad and LnR may be controlled by PKC. Mechanisms of the regulation of HT - 29 cell adhesion by PMA and SP may be involved in their effects on GJIC function. These effects may be related with regulation of E - cad expression by PMA and SP.