Pathogenetic approaches to prevention of age-associated increase of cancer incidence

Aging and cancer: Is glucose a mediator between them?

Aging can increase cancer incidence because of accumulated mutations that initiate cancer and via compromised body control of premalignant lesions development into cancer. Relative contributions of these two factors are debated. Recent evidence suggests that the latter is rate limiting. In particular, hyperglycemia caused by compromised body control of blood glucose may be a factor of selection of somatic mutation-bearing cells for the ability to use glucose for proliferation. High glucose utilization in aerobic glycolysis is a long known characteristic of cancer. The new evidence adds to the concepts that have been being developed starting from mid-1970ies to suggest that age-related shifts in glucose and lipid metabolism increase the risk of cancer and compromise prognoses for cancer patients and to propose antidiabetic biguanides, including metformin, for cancer prevention and as an adjuvant means of cancer treatment aimed at the metabolic rehabilitation of patients. The new evidence is consistent with several effects of glucose contributing to aging and acting synergistically to enhance carcinogenesis. Glucose can affect (i) separate cells (via promoting somatic mutagenesis and epigenetic instability), (ii) cell populations (via being a factor of selection of phenotypic variants in cell populations for higher glucose consumption and, ultimately, for high aerobic glycolysis); (iii) cell microenvironment (via modification of extracellular matrix proteins), and (iv) the systemic levels (via shifting the endocrine regulation of metabolism toward increasing blood lipids and body fat, which compromise immunological surveillance and promote inflammation). Thus, maintenance of youthful metabolic characteristics must be important for cancer prevention and treatment.

Repositioning metformin for cancer prevention and treatment

Metformin is the most commonly prescribed drug for type 2 diabetes (T2DM). Retrospective studies show that metformin is associated with decreased cancer risk. This historical correlation has driven vigorous research campaigns to determine the anticancer mechanisms of metformin. Consolidating the preclinical data is a challenge because unanswered questions remain concerning relevant mechanisms, bioavailability, and genetic factors that confer metformin sensitivity. Perhaps the most important unanswered question is whether metformin has activity against cancer in non-diabetics. In this review we highlight the proposed mechanisms of metformin action in cancer and discuss ongoing clinical trials with metformin in cancer. Improved understanding of these issues will increase the chances for successful application of metformin as an inexpensive, well-tolerated, and effective anticancer agent.

High Bab Birth Weight Andof Hormone-Associated Cancer in Mothers: The Cancer–Cardiovascular Disease Dichotomy and its Possible Causes

The idea of intrauterine or fetal factors being the cause of several prevalent noninfectious diseases in adults has recently gained the status of an axiom. One of the most thoroughly studied predictors is birth weight (BW). Although many published studies point at relations between BW and later adult morbidity or mortality, much less attention is paid to associations between baby BW and maternal morbidity. Available data suggest a sort of dichotomy in these relationships. Thus, cardiovascular risk is higher in mothers of babies with a reduced BW, while cancer risk, mainly of the breast and some other hormone-dependent cancers, is often higher among mothers of babies with a large BW (newborn macrosomia). This review addresses possible causes and endocrine mechanisms of this topic and suggests a ‘particular’ and ‘general’ solution for arising controversy. Emphasis is placed on a probable competition between chronic diseases (mainly, between female hormone-related cancer and cardiovascular pathology) within the concept of multiple causes of death. These associations should be remembered while studying the relation between offspring BW and maternal predisposition to hormone-associated cancers and other noncommunicable diseases.