Inserm, UMR837, Jean Pierre Aubert Research Center, Team #5 Mucins, epithelial differentiation and carcinogenesis, Lille, France.
PLoS One. 2012;7(2):e32232. doi: 10.1371/journal.pone.0032232. Epub 2012 Feb 29.
The mucin MUC4 and its membrane partner the ErbB2 oncogenic receptor are potential interacting partners in human pancreatic tumour development. However, the way they function is still largely unknown. In this work, we aimed to identify the cellular mechanisms and the intracellular signalling pathways under the control of both ErbB2 and MUC4 in a human pancreatic adenocarcinomatous cell line. Using co-immunoprecipitation and GST pull-down, we show that MUC4 and ErbB2 interact in the human pancreatic adenocarcinomatous cell line CAPAN-2 via the EGF domains of MUC4. Stable cell clones were generated in which either MUC4 or ErbB2 were knocked down (KD) by a shRNA approach. Biological properties of these cells were then studied in vitro and in vivo. Our results show that ErbB2-KD cells are more apoptotic and less proliferative (decreased cyclin D1 and increased p27kip1 expression) while migration and invasive properties were not altered. MUC4-KD clones were less proliferative with decreased cyclin D1 expression, G1 cell cycle arrest and altered ErbB2/ErbB3 expression. Their migration properties were reduced whereas invasive properties were increased. Importantly, inhibition of ErbB2 and MUC4 expression did not impair the same signalling pathways (inhibition of MUC4 expression affected the JNK pathway whereas that of ErbB2 altered the MAPK pathway). Finally, ErbB2-KD and MUC4-KD cells showed impaired tumour growth in vivo. Our results show that ErbB2 and MUC4, which interact physically, activate different intracellular signalling pathways to regulate biological properties of CAPAN-2 pancreatic cancer cells.
黏蛋白 MUC4 及其膜伴侣 erbB2 致癌受体可能是人类胰腺肿瘤发展中的潜在相互作用伙伴。然而，它们的功能方式在很大程度上仍然未知。在这项工作中，我们旨在鉴定在人类胰腺腺癌细胞系中受 erbB2 和 MUC4 控制的细胞机制和细胞内信号通路。通过共免疫沉淀和 GST 下拉，我们表明 MUC4 和 erbB2 通过 MUC4 的 EGF 结构域在人胰腺腺癌细胞系 CAPAN-2 中相互作用。通过 shRNA 方法敲低（KD）了 MUC4 或 erbB2 的稳定细胞克隆被生成。然后在体外和体内研究了这些细胞的生物学特性。我们的结果表明，erbB2-KD 细胞凋亡更多，增殖更少（cyclin D1 减少，p27kip1 表达增加），而迁移和侵袭特性没有改变。MUC4-KD 克隆增殖较少，cyclin D1 表达减少，G1 细胞周期停滞，erbB2/erbB3 表达改变。它们的迁移特性降低，而侵袭特性增加。重要的是，抑制 erbB2 和 MUC4 的表达并没有损害相同的信号通路（抑制 MUC4 的表达影响 JNK 通路，而抑制 erbB2 的表达改变 MAPK 通路）。最后，erbB2-KD 和 MUC4-KD 细胞在体内显示出肿瘤生长受损。我们的结果表明，物理相互作用的 erbB2 和 MUC4 激活不同的细胞内信号通路来调节 CAPAN-2 胰腺癌细胞的生物学特性。
