Universidad Nacional Autónoma de México (UNAM), Unidad de Investigación en Biomedicina (UBIMED), Facultad de Estudios Superiores (FES) Iztacala, Tlalnepantla de Baz, 54090, Estado de México, Mexico.
Unidad Funcional de Oncología Torácica, Instituto Nacional de Cancerología (INCan), Av. San Fernando 22, Belisario Domínguez Secc 16, Tlalpan, 14080, Ciudad de México, Mexico.
Eur J Cancer. 2022 Jan;160:189-205. doi: 10.1016/j.ejca.2021.10.032. Epub 2021 Nov 26.
Mesenchyme homeobox-2 (MEOX2)-mediated regulation of glioma-associated oncogene-1 (GLI1) has been associated with poor overall survival, conferring chemoresistance in lung cancer. However, the role of MEOX2/GLI1 in resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs)-based therapy remains unexplored in human lung cancer.
Functional assays using genetic silencing strategy by short hairpin RNAs, as well as cytotoxic (tetrazolium dye MTT) and clonogenic assays, were performed to evaluate MEOX2/GLI1-induced malignancy capacity in lung cancer cells. Further analysis performed includes western blot, qPCR and ChIP-qPCR assays to identify whether MEOX2/GLI1 promote EGFR/AKT/ERK activation, as well as EGFR overexpression through epigenetic mechanisms. Finally, preclinical tumour progression in vivo and progression-free disease interval analyses in patients treated with EGFR-TKI were included.
Overexpressed MEOX2/GLI1 in both EGFR wild-type and EGFR/KRAS-mutated lung cancer cells were detected and involved in the activation/expression of EGFR/AKT/ERK biomarkers. In addition, MEOX2/GLI1 was shown to be involved in the increased proliferation of tumour cells and resistance capacity to cisplatin, EGFR-TKIs (erlotinib and AZD9291 'osimertinib'), AZD8542-SMO, and AZD6244-MEKK1/2. In addition, we identified that MEOX2/GLI1 promote lung tumour cells progression in vivo and are clinically associated with poorer progression-free disease intervals. Finally, both MEOX2 and GLI1 were detected to be epigenetically involved in EGFR expression by reducing both repressive markers polycomb-EZH2 and histone H3K27me3, but, particularly, increasing an activated histone profile H3K27Ac/H3K4me3 at EGFR-gene enhancer-promoter sequences that probably representing a novel EGFR-TKI-based therapy resistance mechanism.
MEOX2/GLI1 promote resistance to cisplatin and EGFR-TKI-based therapy in lung cancer cells, modulating EGFR/AKT/ERK signalling pathway activation, as well as inducing an aberrant epigenetic modulation of the EGFR-gene expression in human lung cancer.
间质同源盒基因-2（MEOX2）介导的Gli 癌基因-1（GLI1）调节与总生存期不良有关，使肺癌产生化疗耐药性。然而，MEOX2/GLI1 在人类肺癌中对表皮生长因子受体酪氨酸激酶抑制剂（EGFR-TKIs）治疗的耐药性中的作用仍未被探索。
使用短发夹 RNA 基因沉默策略进行功能测定，以及细胞毒性（四唑染料 MTT）和集落形成测定，评估肺癌细胞中 MEOX2/GLI1 诱导的恶性能力。进一步的分析包括 Western blot、qPCR 和 ChIP-qPCR 测定，以确定 MEOX2/GLI1 是否通过表观遗传机制促进 EGFR/AKT/ERK 的激活以及 EGFR 的过表达。最后，包括体内肿瘤进展的临床前研究和 EGFR-TKI 治疗患者的无进展疾病间隔分析。
在 EGFR 野生型和 EGFR/KRAS 突变型肺癌细胞中均检测到过表达的 MEOX2/GLI1，并参与 EGFR/AKT/ERK 生物标志物的激活/表达。此外，MEOX2/GLI1 被证明参与肿瘤细胞增殖的增加和对顺铂、EGFR-TKIs（厄洛替尼和 AZD9291“奥希替尼”）、AZD8542-SMO 和 AZD6244-MEKK1/2 的耐药性。此外，我们发现 MEOX2/GLI1 促进体内肺肿瘤细胞的进展，并且与无进展疾病间隔较短有关。最后，通过减少抑制性标记物多梳蛋白-EZH2 和组蛋白 H3K27me3，同时特别增加 EGFR 基因增强子-启动子序列的激活组蛋白谱 H3K27Ac/H3K4me3，我们检测到 MEOX2 和 GLI1 都参与 EGFR 的表观遗传表达，这可能代表一种新的基于 EGFR-TKI 的治疗耐药机制。
MEOX2/GLI1 促进顺铂和基于 EGFR-TKI 的治疗在肺癌细胞中的耐药性，调节 EGFR/AKT/ERK 信号通路的激活，并诱导人类肺癌中 EGFR 基因表达的异常表观遗传调节。
