Metabolic diversity within breast cancer brain-tropic cells determines metastatic fitness.

HER2+ breast cancer patients are presented with either synchronous (S-BM), latent (Lat), or metachronous (M-BM) brain metastases. However, the basis for disparate metastatic fitness among disseminated tumor cells of similar oncotype within a distal organ remains unknown. Here, employing brain metastatic models, we show that metabolic diversity and plasticity within brain-tropic cells determine metastatic fitness. Lactate secreted by aggressive metastatic cells or lactate supplementation to mice bearing Lat cells limits innate immunosurveillance and triggers overt metastasis. Attenuating lactate metabolism in S-BM impedes metastasis, while M-BM adapt and survive as residual disease. In contrast to S-BM, Lat and M-BM survive in equilibrium with innate immunosurveillance, oxidize glutamine, and maintain cellular redox homeostasis through the anionic amino acid transporter xCT. Moreover, xCT expression is significantly higher in matched M-BM brain metastatic samples compared to primary tumors from HER2+ breast cancer patients. Inhibiting xCT function attenuates residual disease and recurrence in these preclinical models.
Competing Interests: Declaration of interests A.B.H. has received research grant support from Takeda and travel support from Puma Biotechnology. C.L.A. receives or has received research grant support from Pfizer, Lilly, and Takeda; holds stock options in Provista and Y-TRAP; and serves or has served in an advisory role to Novartis, Lilly, TAIHO Oncology, Daiichi Sankyo, Merck, AstraZeneca, OrigiMed, Immunomedics, and Susan G. Komen Foundation. R.J.D. is a founder of Atavistik Biosciences and an advisor for Agios Pharmaceuticals, Nirogy Therapeutics, and Vida Ventures.
(Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)