表皮生长因子及其受体对结肠癌干细胞的增殖调控

背景：肿瘤干细胞是肿瘤组织中一小部分具有自我更新、多向分化以及高度增殖能力的肿瘤细胞。研究发现表皮生长因子（EGF）可促进肿瘤干细胞增殖。目的：探讨EGF及其受体（EGFR）在结肠癌干细胞增殖调控中的作用。方法：结肠癌细胞株HT29、HCTll6培养于无血清培养基中，以EGF、碱性成纤维细胞生长因子（bFGF）、胰岛素样生长因子（IGF）分别干预细胞。MTT11法检测EGFR抑制剂吉非替尼对结肠癌细胞球细胞的增殖抑制作用，体外实验检测EGFR抑制剂吉非替尼、PDl53035对细胞球形成的抑制作用，流式细胞术检测细胞凋亡。体内实验检测结肠癌细胞球和细胞株的成瘤能力，real、timePCR检测两者干细胞标记LGR5、Musashi-1和分化标记CK20表达。结果：EGF组HCT116细胞形成的细胞球数量显著高于空白对照、bFGF、IGF组（P〈0．05）。吉非替尼能抑制HCT116细胞球细胞增殖和细胞球形成，并诱导细胞凋亡，作用呈浓度依赖性。HCT116细胞球成瘤时间较细胞株显著缩短，移植瘤体积显著增大（P〈0．05）。LGR5、Musashi-1在细胞球中的表达显著高于细胞株，而CK20在细胞株中的表达显著高于细胞球（P〈0．05）。结论：EGF对结肠癌细胞株HCTll6、HT29形成细胞球具有促进作用。EGFR抑制剂可抑制结肠痛细胞球增殖并诱导细胞凋亡，相关作用可能与调控LGR5、Musashi-1和CK20表i大有关。

Role of Epidermal Growth Factor and its Receptor in Regulating Proliferation of Colon Cancer Stem Cells

Background： Cancer stem cells （CSCs） are a subpopulation of cancer cells that can self-renew, muhilineage- differentiate and proliferate. Studies have shown that epidermal growth factor （EGF） can promote proliferation of CSCs in many tumors. Aims： To investigate the role of EGF and its receptor （EGFR） in regulating proliferation of colon CSCs. Methods： Colon cancer cell lines HT29 and HCTll6 were cultured in serum-free medium and treated with EGF, basic fibroblast growth factor （bFGF） and insulin-like growth factor （IGF）. Inhibition of proliferation of tumor cells from colon tumorspheres by EGFR inhibitor gefitinib was measured by MTT assay. Inhibition of formation of tumorspheres by EGFR inhibitor gefitinib and PD153035 was assessed in vitro. Cell apoptosis was detected by flow cytometry. Tumorigenic capacity of colon tumorspheres and cell line was determined in vivo. Expressions of stem cell markers LGRS, Musashi-1 and differentiation marker CK20 in tumorspheres and cell line were detected by real-time PCR. Results： Number of HCT116 tumorspheres in EGF group was significantly higher than those in blank control, bFGF and IGF groups （ P 〈 O. 05 ）. Gefitinib suppressed proliferation of tumor cells from HCT116 tumorspheres, inhibited tumorsphere formation and induced apoptosis in a concentration-dependent manner. Tumorigenic time of HCT! 16 tumorspheres was significantly faster and tumor volume was significantly larger than HCTll6 cell line （P 〈 0.05 ）. Expressions of LGR5 and Musashi-I were significantly higher and that of CK20 was significantly lower in tumorspheres than in cell line （ P 〈 0.05 ）. Conclusions ：EGF can promote formation of tumorspheres of cohm cancer （：ell lines HCT116 and HT29. EGFR inhibitor can inhibit proliferation of colon tumorspheres and induce apoptosis,and the mechanism may be related to the regulation of LGR5 Musashi01 and CK20.