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Exp Gerontol. 2013 Oct;48(10):1120-8. doi: 10.1016/j.exger.2013.02.016. Epub 2013 Feb 21.

Short-term calorie and protein restriction provide partial protection from chemotoxicity but do not delay glioma progression.

Author information

1
Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0191, USA.

Abstract

Short-term starvation (STS) protects normal cells while simultaneously sensitizing malignant cells to high-dose chemotherapeutic drugs in mice and possibly patients. The fasting-dependent protection of normal cells and sensitization of malignant cells depends, in part, on reduced levels of insulin-like growth factor-1 (IGF-1) and glucose. Calorie restricted diets with defined macronutrient (carbohydrate, protein, fat) ratios were evaluated for the effects on stress sensitization markers and protection in mice treated with high-dose chemotherapy. We show that short-term CR significantly reduced both glucose and IGF-1 levels, but when specific macronutrient deficiencies were tested, only the complete lack of proteins reduced IGF-1 levels. Short-term 50% CR combined with either severe protein-deficiency or ketogenic diets improved chemotoxicity resistance similarly to the standard 50% CR, but did not result in the high protection caused by STS. Notably, a high protein diet reversed the beneficial effects of short-term CR. In a subcutaneous mouse model of glioma, feeding a low protein (4% calories from protein) diet for more than 20days did not delay tumor progression once the tumor became palpable. Also, cycles of short-term (3days) 50% CR did not augment the chemotherapy efficacy of cisplatin in a murine breast cancer model. These results indicate that the protection from chemotoxicity and retardation of the progression of certain tumors achieved with fasting is not obtained with short-term calorie and/or macronutrient restriction.

KEYWORDS:

Calorie restriction; Chemotherapy; Fasting; Insulin-like growth factor 1; Macronutrients; Protein restriction; Stress resistance; Tumor progression

PMID:
23454633
PMCID:
PMC3762887
DOI:
10.1016/j.exger.2013.02.016
[Indexed for MEDLINE]
Free PMC Article

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