Methionine Restriction, Not Cysteine Restriction, Is a Cancer-specific Vulnerability

For all three cancer cell lines, HCT116 colon cancer, HT1080 fibrosarcoma and 143B osteosarcoma, both MR and CR were highly inhibitory in the co-cultures with Hs27 normal fibroblasts. In all cases MR had only a slight effect on normal fibroblasts, but CR was highly toxic to normal fibroblasts. Thus, MR is a cancer-specific vulnerability in contrast to CR which is toxic to both normal and cancer cells and is not a cancer-specificity vulnerability. Therefore, attempting to induce ferroptosis of cancer cells by CR does not appear to have potential as an effective cancer therapy.