Optimized protocol for stable isotope tracing and steady-state metabolomics in mouse HER2+ breast cancer brain metastasis

Analyzing the metabolic dependencies of tumor cells is vital for cancer diagnosis and treatment. Here, we describe a protocol for (13)C-stable glucose and glutamine isotope tracing in mice HER2+ breast cancer brain metastatic lesions. We describe how to inject cancer cells intracardially to generate brain metastatic lesions in mice. We then detail how to perform (13)C-stable isotope infusion in mice with established brain metastasis. Finally, we outline steps for sample collection, processing for metabolite extraction, and analyzing mass spectrometry data. For complete details on the use and execution of this protocol, please refer to Parida et al. (2022).