Physiological media and oxygen levels modulate cancer hallmarks in cultured breast cancer cells

The concepts of physioxia and physiological media for mammalian cell culture have gained attention over the past several years. Although the effects of oxygen tension or nutrient composition have been examined individually, their combined, large‐scale impacts on cancer cell biology remain poorly understood. Here, we integrated transcriptomic, proteomic, and functional analyses to assess how oxygen levels (18% vs. 5% O ₂ ) and medium composition (DMEM vs. Plasmax) influence human breast cancer (MCF7) cells. We found that culturing MCF7 cells in physioxia (5% O ₂ ) and Plasmax medium induces a transcriptional profile that more closely resembles breast tumors in vivo . Moreover, changes in transcript and protein abundance were significantly associated with cellular growth, motility, and metabolism. At the functional level, oxygen level and culture medium affected proliferation, migration, glucose consumption, and metabolic activity in MCF7 cells. We conclude that both oxygen levels and medium composition in culture modulate hallmark cancer phenotypes, underscoring the importance of mimicking physiological microenvironments when studying biological mechanisms and therapeutic approaches in cancer.