Blocking the import of nutrients essential for cancer cell proliferation represents a therapeutic opportunity, but it is unclear which transporters to target. Here we report a CRISPR interference/activation screening platform to systematically interrogate the contribution of nutrient transporters to support cancer cell proliferation in environments ranging from standard culture media to tumours. We applied this platform to identify the transporters of amino acids in leukaemia cells and found that amino acid transport involves high bidirectional flux dependent on the microenvironment composition. While investigating the role of transporters in cystine starved cells, we uncovered a role for serotonin uptake in preventing ferroptosis. Finally, we identified transporters essential for cell proliferation in subcutaneous tumours and found that levels of glucose and amino acids can restrain proliferation in that environment. This study establishes a framework for systematically identifying critical cellular nutrient transporters, characterizing their function and exploring how the tumour microenvironment impacts cancer metabolism.

阻断癌细胞增殖所必需的营养物质的输入是一个治疗机会，但目前尚不清楚针对哪些转运蛋白。在这里，我们报告了一个 CRISPR 干扰/激活筛选平台，系统地询问营养转运蛋白在从标准培养基到肿瘤等环境中支持癌细胞增殖的贡献。我们应用该平台来识别白血病细胞中的氨基酸转运蛋白，发现氨基酸转运涉及依赖于微环境组成的高双向通量。在研究转运蛋白在胱氨酸饥饿细胞中的作用时，我们发现了血清素摄取在预防铁死亡中的作用。最后，我们确定了皮下肿瘤中细胞增殖所必需的转运蛋白，并发现葡萄糖和氨基酸的水平可以抑制该环境中的增殖。这项研究建立了一个框架，用于系统地识别关键的细胞营养转运蛋白，表征其功能并探索肿瘤微环境如何影响癌症代谢。