Takaoka Munenori, Harada Hideki, Andl Claudia D, Oyama Kenji, Naomoto Yoshio, Dempsey Kelly L, Klein-Szanto Andres J, El-Deiry Wafik S, Grimberg Adda, Nakagawa Hiroshi
Gastroenterology Division, Department of Medicine, Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104-2144, USA.
Cancer Res. 2004 Nov 1;64(21):7711-23. doi: 10.1158/0008-5472.CAN-04-0715.
Epidermal growth factor receptor (EGFR) is frequently overexpressed in esophageal carcinoma and its precursor lesions. To gain insights into how EGFR overexpression affects cellular functions in primary human esophageal cells, we performed gene expression profiling and identified insulin-like growth factor-binding protein (IGFBP)-3 as the most up-regulated gene. IGFBP-3 regulates cell proliferation through both insulin-like growth factor-dependent and independent mechanisms. We found that IGFBP-3 mRNA and protein expression was increased in EGFR-overexpressing primary and immortalized human esophageal cells. IGFBP-3 was also up-regulated in EGFR-overexpressing cells in organotypic culture and in EGFR transgenic mice. Furthermore, IGFBP-3 mRNA was overexpressed in 80% of primary esophageal squamous cell carcinomas and 60% of primary esophageal adenocarcinomas. Concomitant up-regulation of EGFR and IGFBP-3 was observed in 60% of primary esophageal squamous cell carcinomas. Immunohistochemistry revealed cytoplasmic localization of IGFBP-3 in the preponderance of preneoplastic and neoplastic esophageal lesions. IGFBP-3 was also overexpressed in esophageal cancer cell lines at both mRNA (60%) and protein (40%) levels. IGFBP-3 secreted by cancer cells was capable of binding to insulin-like growth factor I. Functionally, epidermal growth factor appeared to regulate IGFBP-3 expression in esophageal cancer cell lines. Finally, suppression of IGFBP-3 by small interfering RNA augmented cell proliferation, suggesting that IGFBP-3 may inhibit tumor cell proliferation as a negative feedback mechanism. In aggregate, we have identified for the first time that IGFBP-3 is an aberrantly regulated gene through the EGFR signaling pathway and it may modulate EGFR effects during carcinogenesis.
表皮生长因子受体（EGFR）在食管癌及其癌前病变中常过度表达。为深入了解EGFR过度表达如何影响原代人食管细胞的细胞功能，我们进行了基因表达谱分析，并确定胰岛素样生长因子结合蛋白（IGFBP）-3为上调最明显的基因。IGFBP-3通过胰岛素样生长因子依赖性和非依赖性机制调节细胞增殖。我们发现，在EGFR过度表达的原代和永生化人食管细胞中，IGFBP-3的mRNA和蛋白表达均增加。在器官型培养的EGFR过度表达细胞和EGFR转基因小鼠中，IGFBP-3也上调。此外，80%的原发性食管鳞状细胞癌和60%的原发性食管腺癌中IGFBP-3 mRNA过度表达。在60%的原发性食管鳞状细胞癌中观察到EGFR和IGFBP-3同时上调。免疫组织化学显示，在大多数癌前和癌性食管病变中，IGFBP-3定位于细胞质。在食管癌细胞系中，IGFBP-3在mRNA（60%）和蛋白（40%）水平均过度表达。癌细胞分泌的IGFBP-3能够与胰岛素样生长因子I结合。在功能上，表皮生长因子似乎调节食管癌细胞系中IGFBP-3的表达。最后，小干扰RNA抑制IGFBP-3可增强细胞增殖，这表明IGFBP-3可能作为一种负反馈机制抑制肿瘤细胞增殖。总体而言，我们首次确定IGFBP-3是通过EGFR信号通路异常调节的基因，并且它可能在致癌过程中调节EGFR的作用。
