Lu Yuanyuan, Zhao Xiaodi, Liu Qi, Li Cunxi, Graves-Deal Ramona, Cao Zheng, Singh Bhuminder, Franklin Jeffrey L, Wang Jing, Hu Huaying, Wei Tianying, Yang Mingli, Yeatman Timothy J, Lee Ethan, Saito-Diaz Kenyi, Hinger Scott, Patton James G, Chung Christine H, Emmrich Stephan, Klusmann Jan-Henning, Fan Daiming, Coffey Robert J
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
Nat Med. 2017 Nov;23(11):1331-1341. doi: 10.1038/nm.4424. Epub 2017 Oct 16.
De novo and acquired resistance, which are largely attributed to genetic alterations, are barriers to effective anti-epidermal-growth-factor-receptor (EGFR) therapy. To generate cetuximab-resistant cells, we exposed cetuximab-sensitive colorectal cancer cells to cetuximab in three-dimensional culture. Using whole-exome sequencing and transcriptional profiling, we found that the long non-coding RNA MIR100HG and two embedded microRNAs, miR-100 and miR-125b, were overexpressed in the absence of known genetic events linked to cetuximab resistance. MIR100HG, miR-100 and miR-125b overexpression was also observed in cetuximab-resistant colorectal cancer and head and neck squamous cell cancer cell lines and in tumors from colorectal cancer patients that progressed on cetuximab. miR-100 and miR-125b coordinately repressed five Wnt/β-catenin negative regulators, resulting in increased Wnt signaling, and Wnt inhibition in cetuximab-resistant cells restored cetuximab responsiveness. Our results describe a double-negative feedback loop between MIR100HG and the transcription factor GATA6, whereby GATA6 represses MIR100HG, but this repression is relieved by miR-125b targeting of GATA6. These findings identify a clinically actionable, epigenetic cause of cetuximab resistance.
原发性和获得性耐药在很大程度上归因于基因改变，是有效的抗表皮生长因子受体（EGFR）治疗的障碍。为了生成西妥昔单抗耐药细胞，我们在三维培养中将西妥昔单抗敏感的结肠癌细胞暴露于西妥昔单抗。通过全外显子组测序和转录谱分析，我们发现长链非编码RNA MIR100HG以及两个嵌入的微小RNA即miR-100和miR-125b，在没有与西妥昔单抗耐药相关的已知基因事件的情况下过表达。在西妥昔单抗耐药的结肠癌细胞和头颈部鳞状细胞癌细胞系以及接受西妥昔单抗治疗后病情进展的结肠癌患者的肿瘤中也观察到了MIR100HG、miR-100和miR-125b的过表达。miR-100和miR-125b协同抑制五个Wnt/β-连环蛋白负调节因子，导致Wnt信号增加，而在西妥昔单抗耐药细胞中抑制Wnt可恢复西妥昔单抗的反应性。我们的结果描述了MIR100HG与转录因子GATA6之间的双负反馈环，即GATA6抑制MIR100HG，但miR-125b靶向GATA6可解除这种抑制。这些发现确定了西妥昔单抗耐药的一种临床上可采取行动的表观遗传原因。
