Lanning Nathan J, Castle Joshua P, Singh Simar J, Leon Andre N, Tovar Elizabeth A, Sanghera Amandeep, MacKeigan Jeffrey P, Filipp Fabian V, Graveel Carrie R
California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032 USA.
Van Andel Research Institute, 333 Bostwick Ave, NE, Grand Rapids, MI 49503 USA.
Cancer Metab. 2017 Aug 22;5:6. doi: 10.1186/s40170-017-0168-x. eCollection 2017.
Among breast cancers, the triple-negative breast cancer (TNBC) subtype has the worst prognosis with no approved targeted therapies and only standard chemotherapy as the backbone of systemic therapy. Unique metabolic changes in cancer progression provide innovative therapeutic opportunities. The receptor tyrosine kinases (RTKs) epidermal growth factor receptor (EGFR), and MET receptor are highly expressed in TNBC, making both promising therapeutic targets. RTK signaling profoundly alters cellular metabolism by increasing glucose consumption and subsequently diverting glucose carbon sources into metabolic pathways necessary to support the tumorigenesis. Therefore, detailed metabolic profiles of TNBC subtypes and their response to tyrosine kinase inhibitors may identify therapeutic sensitivities.
We quantified the metabolic profiles of TNBC cell lines representing multiple TNBC subtypes using gas chromatography mass spectrometry. In addition, we subjected MDA-MB-231, MDA-MB-468, Hs578T, and HCC70 cell lines to metabolic flux analysis of basal and maximal glycolytic and mitochondrial oxidative rates. Metabolic pool size and flux measurements were performed in the presence and absence of the MET inhibitor, INC280/capmatinib, and the EGFR inhibitor, erlotinib. Further, the sensitivities of these cells to modulators of core metabolic pathways were determined. In addition, we annotated a rate-limiting metabolic enzymes library and performed a siRNA screen in combination with MET or EGFR inhibitors to validate synergistic effects.
TNBC cell line models displayed significant metabolic heterogeneity with respect to basal and maximal metabolic rates and responses to RTK and metabolic pathway inhibitors. Comprehensive systems biology analysis of metabolic perturbations, combined siRNA and tyrosine kinase inhibitor screens identified a core set of TCA cycle and fatty acid pathways whose perturbation sensitizes TNBC cells to small molecule targeting of receptor tyrosine kinases.
Similar to the genomic heterogeneity observed in TNBC, our results reveal metabolic heterogeneity among TNBC subtypes and demonstrate that understanding metabolic profiles and drug responses may prove valuable in targeting TNBC subtypes and identifying therapeutic susceptibilities in TNBC patients. Perturbation of metabolic pathways sensitizes TNBC to inhibition of receptor tyrosine kinases. Such metabolic vulnerabilities offer promise for effective therapeutic targeting for TNBC patients.
在乳腺癌中，三阴性乳腺癌（TNBC）亚型预后最差，没有获批的靶向治疗方法，仅以标准化疗作为全身治疗的基础。癌症进展过程中独特的代谢变化提供了创新的治疗机会。受体酪氨酸激酶（RTK）表皮生长因子受体（EGFR）和MET受体在TNBC中高表达，使其成为有前景的治疗靶点。RTK信号传导通过增加葡萄糖消耗并随后将葡萄糖碳源转移到支持肿瘤发生所需的代谢途径中，深刻改变细胞代谢。因此，TNBC亚型的详细代谢谱及其对酪氨酸激酶抑制剂的反应可能确定治疗敏感性。
我们使用气相色谱 - 质谱法定量分析了代表多种TNBC亚型的TNBC细胞系的代谢谱。此外，我们对MDA - MB - 231、MDA - MB - 468、Hs578T和HCC70细胞系进行了基础和最大糖酵解及线粒体氧化速率的代谢通量分析。在存在和不存在MET抑制剂INC280/卡马替尼以及EGFR抑制剂厄洛替尼的情况下进行代谢池大小和通量测量。此外，确定了这些细胞对核心代谢途径调节剂的敏感性。此外，我们注释了一个限速代谢酶文库，并与MET或EGFR抑制剂联合进行了siRNA筛选以验证协同效应。
TNBC细胞系模型在基础和最大代谢速率以及对RTK和代谢途径抑制剂的反应方面表现出显著的代谢异质性。对代谢扰动的综合系统生物学分析、联合siRNA和酪氨酸激酶抑制剂筛选确定了一组核心的三羧酸循环和脂肪酸途径，其扰动使TNBC细胞对受体酪氨酸激酶的小分子靶向敏感。
与TNBC中观察到的基因组异质性类似，我们的结果揭示了TNBC亚型之间的代谢异质性，并表明了解代谢谱和药物反应可能在靶向TNBC亚型和确定TNBC患者的治疗易感性方面具有重要价值。代谢途径的扰动使TNBC对受体酪氨酸激酶的抑制敏感。这种代谢脆弱性为TNBC患者的有效治疗靶向提供了希望。
