Biosynthesis is up-regulated in tumors and thus the demand for anabolic intermediates is increased. The metabolic routes providing the building blocks for macromolecules are thus a very attractive target as they are not normally up-regulated in a normal quiescent cell. Some routes for glycolysis-derived intermediates production have been identified, but these do not constitute the whole pool of biosynthetic molecules in the cell, as many of these derive from mitochondria in the Krebs cycle. Indeed, this metabolic pathway is considered a "biosynthetic hub" from which anabolism is fed. If a metabolite efflux is indeed occurring, anaplerotic reactions must keep a steady supply of substrates. In spite of this obvious relevance of anaplerosis, it has been poorly characterized in the malignant cell context. Glutaminolysis and and pyruvate carboxylation are two pathways that function in an anaplerotic fashion. In spite of the increasing evidence implicating these two processes in cancer metabolism their role as intermediate providers is overlooked. In this review we analyze the implications of an active anaplerosis in cancer and we discuss experimental evidence showing the relevance of these metabolic routes in tumor physiology.

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Objectives: In this study, we evaluated the association between perceived stress and indicators of metabolic syndrome and how this association is mediated by sleep problems, unhealthy eating habits, and night eating syndrome, in addition to serum levels of ghrelin and cortisol in university students. Methods: We recruited 192 students from a public university in Mexico. Weight, height, waist circumference and blood pressure were taken in accordance with standard protocols. Validated questionnaires were used to assess perceived stress, sleep quality and eating habits. Fasting blood samples were taken to measure ghrelin, cortisol, triglycerides, glucose and HDL-C. Results: Path Analysis indicated direct positive effects of stress over PSQI (β = 0.341) and NES (β = 0.443); PSQI over NES (β = 0.233) and NES over glucose (β = 0.170), triglycerides over LDL-C (β = 0.215), waist circumference over SBP (β = 0.259). Likewise, standardized negative regression weights of PSQI over Diet Quality Index (β = -0.239) and ghrelin concentrations (β = -0.132), ghrelin over Diet Quality Index (β = -0.188) and waist circumference (β = -0.147). Diet Quality Index over triglycerides (β = -0.184); sleep duration over systolic blood pressure (β = -0.242); waist circumference over HDL-C (β = -0.256). Conclusion: Psychological stress leads to increased indicators of MetS via decreased sleep quality, inadequate eating habits and eating behavior in university students.

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