HGF rescues colorectal cancer cells from EGFR inhibition via MET activation.
HGF rescues colorectal cancer cells from EGFR inhibition via MET activation.
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DOI：
10.1158/1078-0432.ccr-10-0568
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发表时间：
2011-02-01
期刊：
影响因子：
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通讯作者：
Weiser MR
中科院分区：
文献类型：
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作者：
Liska D;Chen CT;Bachleitner-Hofmann T;Christensen JG;Weiser MR
西妥昔单抗是一种靶向表皮生长因子受体（EGFR）的抗体，在结直肠癌（CRC）中具有活性。然而，回复率只有10%到20%。在这里，我们研究肝细胞生长因子（HGF）依赖的间充质上皮转化因子（MET）激活作为西妥昔单抗耐药的中介，通过CRC细胞系的信号多样化。用不同浓度和组合的EGF、HGF、西妥昔单抗和PHA-665752（一种高度特异性的MET激酶抑制剂）处理DiFi、GEO和LIM1215细胞。生物学终点包括增殖、细胞周期阻滞和细胞凋亡。增殖用WST-1测定，协同作用用等温图测定。免疫印迹法检测表达和信号传导。EGFR和MET在这些结直肠癌细胞系中共表达，双受体激活协同增加增殖。西妥昔单抗抑制细胞生长60% - 80%，同时伴有EGFR、MAPK和/或AKT的去磷酸化。在西妥昔单抗处理的细胞中加入HGF可磷酸化MET，但不磷酸化EGFR或ErbB3，重新刺激MAPK和AKT通路，恢复细胞增殖，并使细胞免于G1阻滞和凋亡。重要的是，这种效应可以通过用PHA-665752抑制MET激活或用RNAi下调MET表达来消除。hgf诱导的MET活化是结直肠癌西妥昔单抗耐药的新机制。抑制HGF-MET途径可改善结直肠癌患者对EGFR抑制剂的应答，联合治疗有待进一步研究。
Cetuximab, an antibody targeting the epidermal growth factor receptor (EGFR), is active in colorectal cancer (CRC). However, response rates range from only 10% to 20%. Here, we investigate hepatocyte growth factor (HGF)-dependent mesenchymal-epithelial transition factor (MET) activation as a mediator of cetuximab resistance through signal diversification in CRC cell lines. DiFi, GEO, and LIM1215 cells were treated with varying concentrations and combinations of EGF, HGF, cetuximab, and PHA-665752 (a highly specific MET kinase inhibitor). Biological end points included proliferation, cell-cycle arrest, and apoptosis. Proliferation was measured using WST-1 assays and synergy investigated via isobolograms. Expression and signaling were examined using immunoblotting. EGFR and MET are co-expressed in these CRC cell lines, and dual receptor activation synergistically increased proliferation. Cetuximab inhibited cell growth by 60% to 80%, with an associated dephosphorylation of EGFR, MAPK and/or AKT. Addition of HGF to cetuximab-treated cells phosphorylated MET, but not EGFR or ErbB3, re-stimulated the MAPK and AKT pathways, restored cell proliferation, and rescued cells from G1 arrest and apoptosis. Importantly, this effect could be abrogated by inhibiting MET activation with PHA-665752 or by downregulating MET expression with RNAi. HGF-induced MET activation is a novel mechanism of cetuximab resistance in CRC. Inhibition of the HGF-MET pathway may improve response to EGFR inhibitors in CRC, and combination therapy should be further investigated.