PDF(Pubmed)
Abstract：
Brain metastatic breast cancer is particularly lethal largely due to therapeutic resistance. Almost half of the patients with metastatic HER2-positive breast cancer develop brain metastases, representing a major clinical challenge. We previously described that cancer-associated fibroblasts are an important source of resistance in primary tumors. Here, we report that breast cancer brain metastasis stromal cell interactions in 3D cocultures induce therapeutic resistance to HER2-targeting agents, particularly to the small molecule inhibitor of HER2/EGFR neratinib. We investigated the underlying mechanisms using a synthetic Notch reporter system enabling the sorting of cancer cells that directly interact with stromal cells. We identified mucins and bulky glycoprotein synthesis as top-up-regulated genes and pathways by comparing the gene expression and chromatin profiles of stroma-contact and no-contact cancer cells before and after neratinib treatment. Glycoprotein gene signatures were also enriched in human brain metastases compared to primary tumors. We confirmed increased glycocalyx surrounding cocultures by immunofluorescence and showed that mucinase treatment increased sensitivity to neratinib by enabling a more efficient inhibition of EGFR/HER2 signaling in cancer cells. Overexpression of truncated MUC1 lacking the intracellular domain as a model of increased glycocalyx-induced resistance to neratinib both in cell culture and in experimental brain metastases in immunodeficient mice. Our results highlight the importance of glycoproteins as a resistance mechanism to HER2-targeting therapies in breast cancer brain metastases.
摘要：
脑转移性乳腺癌在很大程度上由于治疗抗性而特别致命。几乎一半的转移性HER2阳性乳腺癌患者发生脑转移，代表了一个重大的临床挑战。我们先前描述了癌症相关的成纤维细胞是原发性肿瘤中抗性的重要来源。这里,我们报道3D共培养物中乳腺癌脑转移基质细胞相互作用诱导对HER2靶向药物的治疗抗性,特别是HER2/EGFRneratinib的小分子抑制剂。我们使用合成的Notch报告系统研究了潜在的机制，该系统能够分选与基质细胞直接相互作用的癌细胞。我们通过比较neratinib治疗前后基质接触和非接触癌细胞的基因表达和染色质谱，将粘蛋白和大糖蛋白合成鉴定为过度调节的基因和途径。与原发性肿瘤相比,糖蛋白基因特征也在人脑转移中富集。我们通过免疫荧光证实了共培养物周围的糖萼增加，并表明粘胺酶治疗通过更有效地抑制癌细胞中的EGFR/HER2信号传导而增加了对neratinib的敏感性。缺乏胞内结构域的截短MUC1的过表达作为在免疫缺陷小鼠的细胞培养和实验性脑转移中糖萼诱导的对neratinib抗性增加的模型。我们的结果强调了糖蛋白作为乳腺癌脑转移中HER2靶向治疗的耐药机制的重要性。
