Iommelli Francesca, De Rosa Viviana, Terlizzi Cristina, Fonti Rosa, Camerlingo Rosa, Stoppelli Maria Patrizia, Stewart C Allison, Byers Lauren Averett, Piwnica-Worms David, Del Vecchio Silvana
Institute of Biostructures and Bioimaging, National Research Council, 80145 Naples, Italy.
Department of Advanced Biomedical Sciences, University "Federico II", 80131 Naples, Italy.
Cancers (Basel). 2021 Apr 22;13(9):2022. doi: 10.3390/cancers13092022.
Notch1 plays a key role in epithelial-mesenchymal transition (EMT) and in the maintenance of cancer stem cells. In the present study we tested whether high levels of activated Notch1 in oncogene-driven NSCLC can induce a reversible shift of driver dependence from EGFR to Notch1, and thus causing resistance to EGFR inhibitors. Adherent cells (parental) and tumor spheres (TS) from NSCLC H1975 cells and patient-derived CD133-positive cells were tested for EGFR and Notch1 signaling cascade. The Notch1-dependent modulation of EGFR, NCID, Hes1, p53, and Sp1 were then analyzed in parental cells by binding assays with a Notch1 agonist, DLL4. TS were more resistant than parental cells to EGFR inhibitors. A strong upregulation of Notch1 and a concomitant downregulation of EGFR were observed in TS compared to parental cells. Parental cell exposure to DLL4 showed a dose-dependent decrease of EGFR and a simultaneous increase of NCID, Hes1, p53, and Sp1, along with the dislocation of Sp1 from the promoter. Furthermore, an enhanced interaction between p53 and Sp1 was observed in TS. In NSCLC cells, high levels of active Notch1 can promote a reversible shift of driver dependence from EGFR to Notch1, leading to resistance to EGFR inhibitors.
Notch1在上皮-间质转化（EMT）以及癌症干细胞的维持中发挥关键作用。在本研究中，我们测试了在癌基因驱动的非小细胞肺癌（NSCLC）中，高水平的活化Notch1是否能诱导驱动依赖从表皮生长因子受体（EGFR）可逆地转变为Notch1，从而导致对EGFR抑制剂产生耐药性。对来自NSCLC H1975细胞的贴壁细胞（亲代细胞）和肿瘤球（TS）以及患者来源的CD133阳性细胞进行了EGFR和Notch1信号级联检测。然后，通过与Notch1激动剂DLL4的结合试验，在亲代细胞中分析了Notch1对EGFR、NCID、Hes1、p53和Sp1的依赖性调节。TS比亲代细胞对EGFR抑制剂更具耐药性。与亲代细胞相比，在TS中观察到Notch1强烈上调，同时EGFR下调。亲代细胞暴露于DLL4后，EGFR呈剂量依赖性降低，同时NCID、Hes1、p53和Sp1增加，以及Sp1从启动子处移位。此外，在TS中观察到p53与Sp1之间的相互作用增强。在NSCLC细胞中，高水平的活性Notch1可促进驱动依赖从EGFR可逆地转变为Notch1，从而导致对EGFR抑制剂产生耐药性。
