MUC1-C IS ESSENTIAL FOR ESTABLISHING AND RECALLING INFLAMMATORY MEMORY OF OSIMERTINIB RESISTANCE IN NSCLC CELLS [H1975-RT_vs_H1975-OR]

MUC1-C is necessary for establishing and recalling resistance of NSCLC cells to osimertinib by driving an inflammatory memory responseThe oncogenic MUC1-C protein functions as a master regulator of NSCLC cell resistance to osimertinib by unclear mechanisms. We report that MUC1-C-mediated regulation of STAT1 and the interferon (IFN) type I/II pathways is necessary for establishing osimertinib resistance. Studies of osimertinib-resistant NSCLC cells selected for growth in the absence of drug further demonstrate that revertant cells are dependent on MUC1-C for recalling resistance to osimertinib. We show that establishing and recalling osimertinib resistance is dependent on activation of the MUC1 gene at (i) a proximal enhancer-like signature 1 (pELS-1) by MUC1-C and STAT1 and (ii) a pELS-2 by MUC1-C, JUN/AP-1 and PBAF. The MUC1 pELS regions function as memory domains for activation of MUC1-C and downstream STAT1 and IFN stimulated genes in conferring osimertinib resistance. Of clinical relevance, we report that the MUC1-C-driven inflammatory responses are induced in patient-derived, osimertinib-resistant MGH170 NSCLC cells with MET amplification. Our results further demonstrate that MGH170 cells are dependent on the MUC1-C-induced inflammatory response for resistance to the osimertinib and combination of osimertinib with the MET inhibitor capmatinib. These findings indicate that MUC1-C is necessary for establishing and recalling resistance of NSCLC cells to osimertinib by driving an inflammatory memory response. Overall design: Comparison between H1975-OR, the osimertinib-resistant cell line, and H1975-RT cells, which had osimertinib removed for a longer period from H1975-OR and moderately regained sensitivity (H1975-OR vs H1975-RT). Treatment of H1975-OR = Osimertinib Treatment of H1975-RT = None

黏蛋白1-C（MUC1-C）是通过驱动炎症记忆应答，建立并恢复非小细胞肺癌（non-small cell lung cancer, NSCLC）细胞对奥希替尼（osimertinib）耐药性的必需因子。
致癌性MUC1-C蛋白作为非小细胞肺癌细胞对奥希替尼产生耐药性的核心调控因子，但其具体调控机制此前尚未明确。本研究发现，MUC1-C介导的信号转导与转录激活因子1（STAT1）以及I/II型干扰素（IFN）通路调控，是建立奥希替尼耐药性的必要条件。
针对在无药物培养条件下筛选获得的奥希替尼耐药非小细胞肺癌细胞的进一步研究证实，耐药逆转细胞依赖MUC1-C以恢复对奥希替尼的耐药性。本研究表明，建立与恢复奥希替尼耐药性依赖于MUC1基因的激活，具体通过两种机制实现：(i) 由MUC1-C与STAT1介导的近端增强子样特征1（proximal enhancer-like signature 1, pELS-1）区域，以及(ii) 由MUC1-C、JUN/AP-1与PBAF复合物介导的pELS-2区域。MUC1基因的pELS区域可作为记忆结构域，激活MUC1-C及其下游STAT1与干扰素刺激基因，从而赋予细胞奥希替尼耐药性。
具有临床相关性的是，本研究发现，在携带MET扩增的患者来源奥希替尼耐药MGH170非小细胞肺癌细胞中，可诱导MUC1-C介导的炎症应答。本研究进一步证实，MGH170细胞依赖MUC1-C诱导的炎症应答以抵抗奥希替尼，以及奥希替尼与MET抑制剂卡马替尼（capmatinib）的联合治疗。上述研究结果表明，MUC1-C通过驱动炎症记忆应答，是建立并恢复非小细胞肺癌细胞对奥希替尼耐药性的必需因子。

整体实验设计：对比奥希替尼耐药细胞系H1975-OR与H1975-RT细胞——后者是从H1975-OR中移除奥希替尼培养较长时间后，中度恢复药物敏感性的细胞系（H1975-OR vs H1975-RT）。H1975-OR的处理方式为奥希替尼处理；H1975-RT的处理方式为无处理。