✍🏼 Bradley I. Reinfeld, Matthew Z. Madden, Melissa M. Wolf, Anna Chytil, Jackie E. Bader, Andrew R. Patterson, Ayaka Sugiura, Allison S. Cohen, Ahmed Ali, Brian T. Do, Alexander Muir, Caroline A. Lewis, Rachel A. Hongo, Kirsten L. Young, Rachel E. Brown, Vera M. Todd, Tessa Huffstater, Abin Abraham, Richard T. O’Neil, Matthew H. Wilson, Fuxue Xin, M. Noor Tantawy, W. David Merryman, Rachelle W. Johnson, W. Kimryn Rathmell

🏠 Vanderbilt University Medical Center

📑 Nature  (2021)

Abstract

Cancer cells characteristically consume glucose through Warburg metabolism, a process that forms the basis of tumour imaging by positron emission tomography (PET). Tumour-infiltrating immune cells also rely on glucose, and impaired immune cell metabolism in the tumour microenvironment (TME) contributes to immune evasion by tumour cells. However, whether the metabolism of immune cells is dysregulated in the TME by cell-intrinsic programs or by competition with cancer cells for limited nutrients remains unclear. Here we used PET tracers to measure the access to and uptake of glucose and glutamine by specific cell subsets in the TME. Notably, myeloid cells had the greatest capacity to take up intratumoral glucose, followed by T cells and cancer cells, across a range of cancer models. By contrast, cancer cells showed the highest uptake of glutamine. This distinct nutrient partitioning was programmed in a cell-intrinsic manner through mTORC1 signalling and the expression of genes related to the metabolism of glucose and glutamine. Inhibiting glutamine uptake enhanced glucose uptake across tumour-resident cell types, showing that glutamine metabolism suppresses glucose uptake without glucose being a limiting factor in the TME. Thus, cell-intrinsic programs drive the preferential acquisition of glucose and glutamine by immune and cancer cells, respectively. Cell-selective partitioning of these nutrients could be exploited to develop therapies and imaging strategies to enhance or monitor the metabolic programs and activities of specific cell populations in the TME.

How is the WOLF used in this study
The authors needed to isolate specific live cell populations from dissociated solid tumors in order to assess nutrient uptake and metabolic programming in distinct tumour-resident cell types (e.g., immune subsets versus cancer cells). To accomplish this, they used a WOLF cell sorter, a gentle, microfluidics-based fluorescence-activated cell sorting platform, to purify viable single cells from tumor digests based on fluorescent markers and size/viability parameters. This enabled them to obtain highly enriched populations of tumor-infiltrating immune cells and cancer cells with minimal stress or damage, preserving their native metabolic states for downstream analyses such as nutrient tracer uptake measurements and single-cell profiling. The precise and high-viability sorting was critical for accurately comparing glucose and glutamine uptake across cell subsets in the tumour microenvironment and for linking these metabolic phenotypes with intrinsic cellular programming rather than tissue dissociation artifacts.