Fasting cycles retard growth of tumors and sensitize a range of cancer cell types to chemotherapy.
Level 5 - mechanism / opinion, no new human data
Bench, in vitro cell line, and animal (mouse) experimental models without human clinical data
PubMed 22323820 · doi:10.1126/scitranslmed.3003293
What was done
Researchers evaluated the effects of short-term starvation (fasting) alone and combined with chemotherapy across in vitro and in vivo models. They tested yeast expressing the oncogene-like RAS2(val19) under oxidative stress, 17 mammalian cancer cell lines exposed to chemotherapeutic agents, and mouse models of melanoma, glioma, breast cancer, and neuroblastoma. In 4T1 breast cancer cells, they analyzed molecular markers including Akt and S6 kinase phosphorylation, oxidative stress, caspase-3 cleavage, DNA damage, and apoptosis.
What was found
Starvation conditions sensitized RAS2(val19)-expressing yeast to oxidative stress and 15 of 17 mammalian cancer cell lines to chemotherapy. Fasting cycles alone delayed tumor progression as effectively as chemotherapeutic agents and enhanced chemotherapy efficacy against melanoma, glioma, and breast cancer cells. In mouse models of neuroblastoma, fasting cycles combined with chemotherapy produced long-term cancer-free survival, whereas neither fasting nor chemotherapy alone did. In 4T1 cells, short-term starvation increased Akt and S6 kinase phosphorylation, oxidative stress, caspase-3 cleavage, DNA damage, and apoptosis. Quantitative values, survival rates, and effect sizes were not reported in the abstract.
Why it matters
This study provides preclinical evidence that fasting cycles induce differential stress sensitization in malignant cells, potentially enhancing chemotherapy efficacy and retarding tumor growth across multiple cancer types.
Limits
The findings are limited to yeast, in vitro cell cultures, and mouse models; clinical efficacy and safety in human cancer patients were not assessed. The abstract does not report animal sample sizes, exact survival percentages, or quantitative effect sizes. Potential risks of fasting, such as malnutrition and tolerability issues during human chemotherapy regimens, were not evaluated.
Cited by
- supports In mouse cancer models, cancer-free survival is achieved only when fasting or fasting-mimicking diets are combined with chemotherapy, whereas each intervention alone is almost never curative.