Department of Paterson Institute, Manchester, UK.
Carcinogenesis. 2012 Oct;33(10):1930-9. doi: 10.1093/carcin/bgs231. Epub 2012 Jul 12.
Colon cancer growth requires growth-promoting interactions between malignant colonocytes and stromal cells. Epidermal growth factor receptors (EGFR) are expressed on colonocytes and many stromal cells. Furthermore, EGFR is required for efficient tumorigenesis in experimental colon cancer models. To dissect the cell-specific role of EGFR, we manipulated receptor function on stromal cells and cancer cells. To assess the role of stromal EGFR, HCT116 human colon cancer cells were implanted into immunodeficient mice expressing dominant negative (DN) Egfr(Velvet/+) or Egfr(+/+). To assess the role of cancer cell EGFR, HCT116 transfectants expressing inducible DN-Egfr were implanted into immunodeficient mice. To dissect EGFR signals in vitro, we examined colon cancer cells in monoculture or in cocultures with fibroblasts for EGFR transactivation and prostaglandin synthase 2 (PTGS2) induction. EGFR signals were determined by blotting, immunostaining and real-time PCR. Tumor xenografts in Egfr(Velvet/+) mice were significantly smaller than tumors in Egfr(+/+) mice, with decreased proliferation (Ki67) and increased apoptosis (cleaved caspase-3) in cancer cells and decreased stromal blood vessels. Mouse stromal transforming growth factor alpha (TGFA), amphiregulin (AREG), PTGS2 and Il1b and interleukin-1 receptor 1 (Il1r1) transcripts and cancer cell beta catenin (CTNNB1) and cyclin D1 (CCND1) were significantly lower in tumors obtained from Egfr(Velvet/+) mice. DN-EGFR HCT116 transfectants also formed significantly smaller tumors with reduced mouse Areg, Ptgs2, Il1b and Il1r1 transcripts. Coculture increased Caco-2 phospho-active ERBB (pERBB2), whereas DN-EGFR in Caco-2 cells suppressed fibroblast PTGS2 and prostaglandin E2 (PGE2). In monoculture, interleukin 1 beta (IL1B) transactivated EGFR in HCT116 cells. Stromal cell and colonocyte EGFRs are required for robust EGFR signals and efficient tumor growth, which involve EGFR-interleukin-1 crosstalk.
结肠癌的生长需要恶性结肠细胞和基质细胞之间的促进生长的相互作用。表皮生长因子受体（EGFR）在结肠细胞和许多基质细胞上表达。此外，EGFR 是实验性结肠癌模型中高效肿瘤发生所必需的。为了剖析 EGFR 的细胞特异性作用，我们对基质细胞和癌细胞上的受体功能进行了操作。为了评估基质 EGFR 的作用，将 HCT116 人结肠癌细胞植入表达显性负（DN）Egfr（Velvet/+）或 Egfr（+/+）的免疫缺陷小鼠中。为了评估癌细胞 EGFR 的作用，将表达可诱导 DN-Egfr 的 HCT116 转染体植入免疫缺陷小鼠中。为了在体外剖析 EGFR 信号，我们检查了在单独培养或与成纤维细胞共培养的结肠癌细胞中的 EGFR 转激活和前列腺素合酶 2（PTGS2）诱导。通过印迹、免疫染色和实时 PCR 测定 EGFR 信号。在 Egfr（Velvet/+）小鼠中的肿瘤异种移植物明显小于 Egfr（+/+）小鼠中的肿瘤，癌细胞中的增殖（Ki67）减少和凋亡（cleaved caspase-3）增加，以及基质血管减少。从 Egfr（Velvet/+）小鼠获得的肿瘤中，小鼠基质转化生长因子 alpha（TGFA）、 Amphiregulin（AREG）、PTGS2 和 Il1b 以及白细胞介素 1 受体 1（Il1r1）转录物以及癌细胞β-连环蛋白（CTNNB1）和细胞周期蛋白 D1（CCND1）显著降低。DN-EGFR HCT116 转染体也形成明显较小的肿瘤，减少了小鼠 Areg、Ptgs2、Il1b 和 Il1r1 转录物。共培养增加了 Caco-2 磷酸化活性 ERBB（pERBB2），而 Caco-2 细胞中的 DN-EGFR 抑制成纤维细胞 PTGS2 和前列腺素 E2（PGE2）。在单独培养中，白细胞介素 1 β（IL1B）转激活了 HCT116 细胞中的 EGFR。基质细胞和结肠细胞 EGFR 是强大的 EGFR 信号和有效肿瘤生长所必需的，这涉及 EGFR-白细胞介素 1 相互作用。
