Division of Rheumatology and Immunology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA.
Sci Signal. 2017 Dec 5;10(508):eaan4667. doi: 10.1126/scisignal.aan4667.
Malignant tumors reprogram cellular metabolism to support cancer cell proliferation and survival. Although most cancers depend on a high rate of aerobic glycolysis, many cancer cells also display addiction to glutamine. Glutamine transporters and glutaminase activity are critical for glutamine metabolism in tumor cells. We found that the receptor tyrosine kinase EphA2 activated the TEAD family transcriptional coactivators YAP and TAZ (YAP/TAZ), likely in a ligand-independent manner, to promote glutamine metabolism in cells and mouse models of HER2-positive breast cancer. Overexpression of EphA2 induced the nuclear accumulation of YAP and TAZ and increased the expression of YAP/TAZ target genes. Inhibition of the GTPase Rho or the kinase ROCK abolished EphA2-dependent YAP/TAZ nuclear localization. Silencing or substantially reduced the amount of intracellular glutamate through decreased expression of and , respectively, genes that encode proteins that promote glutamine uptake and metabolism. The regulatory DNA elements of both and contain TEAD binding sites and were bound by TEAD4 in an EphA2-dependent manner. In patient breast cancer tissues, expression positively correlated with that of and , as well as that of and Although high expression of predicted enhanced metastatic potential and poor patient survival, it also rendered HER2-positive breast cancer cells more sensitive to glutaminase inhibition. The findings define a previously unknown mechanism of EphA2-mediated glutaminolysis through YAP/TAZ activation in HER2-positive breast cancer and identify potential therapeutic targets in patients.
恶性肿瘤重新编程细胞代谢以支持癌细胞的增殖和存活。尽管大多数癌症依赖于高有氧糖酵解率,但许多癌细胞也表现出对谷氨酰胺的依赖。谷氨酰胺转运体和谷氨酰胺酶活性对于肿瘤细胞中的谷氨酰胺代谢至关重要。我们发现受体酪氨酸激酶 EphA2 以配体非依赖性的方式激活 TEAD 家族转录共激活因子 YAP 和 TAZ(YAP/TAZ),以促进 HER2 阳性乳腺癌细胞和小鼠模型中的谷氨酰胺代谢。EphA2 的过表达诱导 YAP 和 TAZ 的核积累,并增加 YAP/TAZ 靶基因的表达。抑制 Rho GTPase 或激酶 ROCK 可消除 EphA2 依赖性 YAP/TAZ 核定位。沉默 或 分别通过降低 和 的表达,从而显著减少细胞内谷氨酸的含量, 和 分别编码促进谷氨酰胺摄取和代谢的蛋白质。 和 的调节 DNA 元件均含有 TEAD 结合位点,并以 EphA2 依赖的方式与 TEAD4 结合。在患者的乳腺癌组织中, 表达与 、 和 表达呈正相关。虽然 的高表达预示着增强的转移潜力和较差的患者生存,但它也使 HER2 阳性乳腺癌细胞对谷氨酰胺酶抑制剂更敏感。这些发现定义了 EphA2 通过 YAP/TAZ 激活介导的 HER2 阳性乳腺癌中谷氨酰胺分解的先前未知机制,并确定了患者中的潜在治疗靶点。