Protein kinase Calpha inhibitor enhances the sensitivity of human pancreatic cancer HPAC cells to Clostridium perfringens enterotoxin via claudin-4
Protein kinase Calpha inhibitor enhances the sensitivity of human pancreatic cancer HPAC cells to Clostridium perfringens enterotoxin via claudin-4
复制标题
蛋白激酶Cα抑制剂通过claudin-4增强人胰腺癌HPAC细胞对产气荚膜梭菌肠毒素的敏感性
DOI：
10.1007/s00441-011-1287-2
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Sawada N
中科院分区：
文献类型：
--
作者：
Kyuno D;Kojima T;Ito T;Yamaguchi H;Tsujiwaki M;Takasawa A;Murata M;Tanaka S;Hirata K;Sawada N
与正常组织相比，蛋白激酶C（PKC）在癌症（包括胰腺癌）中过表达。此外，PKCα被认为是诊断癌症的生物标志物之一。在几种人类癌症中，密蛋白紧密连接分子受到异常调节，因此是产气荚膜梭菌肠毒素（CPE）诊断和治疗的有希望的分子靶点。为探讨PKCα激活对胰腺癌细胞紧密连接功能的影响，采用PKC激活剂12-O-十四烷酰佛波醇13-乙酸酯（TPA）处理高度分化的人胰腺癌细胞系HPAC，观察其紧密连接分子的表达和屏障功能的变化。TPA处理改变了磷酸化PKC α的活性，并导致Snail家族成员Snail、Slug和Smad相互作用蛋白1的增加和E-钙粘蛋白的减少。在用TPA处理的HPAC细胞中，观察到claudin-1的下调和claudin-4和occludin在核周围的错误定位，以及紧密连接链的数量减少和claudin-4的磷酸化增加。TPA处理后，细胞屏障功能和CPE的细胞毒性明显降低。TPA治疗后的所有这些变化都被panPKC和PKCα抑制剂所阻止。这些发现表明，在人胰腺癌细胞中，PKCα激活下调了紧密连接功能，作为一个屏障，并作为CPE的受体，通过修饰claudin-1和-4在上皮细胞向间充质细胞转化的变化。PKCα抑制剂可能通过claudin-4的CPE细胞毒性而成为抗人胰腺癌细胞的潜在治疗药物。
Protein kinase C (PKC) is overexpressed in cancer, including pancreatic cancer, compared with normal tissue. Moreover, PKCα is considered one of the biomarkers for the diagnosis of cancers. In several human cancers, the claudin tight junction molecules are abnormally regulated and are thus promising molecular targets for diagnosis and therapy withClostridium perfringensenterotoxin (CPE). In order to investigate the changes of tight junction functions of claudins via PKCα activation in pancreatic cancer cells, the well-differentiated human pancreatic cancer cell line HPAC, with its highly expressed tight junction molecules and well-developed barrier function, was treated with the PKC activator 12-O-tetradecanoylphorbol 13-acetate (TPA). Treatment with TPA modified the activity of phosphoPKCα and caused an increase of the Snail family members Snail, Slug and Smad-interacting protein 1 and a decrease of E-cadherin. In HPAC cells treated with TPA, downregulation of claudin-1 and mislocalization of claudin-4 and occludin around the nuclei were observed, together with a decrease in the numbers of tight junction strands and an increase in phosphorylation of claudin-4. The barrier function and the cytotoxicity of CPE were significantly decreased on TPA treatment. All such changes after TPA treatment were prevented by inhibitors of panPKC and PKCα. These findings suggest that, in human pancreatic cancer cells, PKCα activation downregulates tight junction functions as a barrier and as a receptor of CPE via the modification of claudin-1 and −4 during epithelial to mesenchymal transition-like changes. PKCα inhibitors might represent potential therapeutic agents against human pancreatic cancer cells by use of CPE cytotoxicity via claudin-4.