[Prospects of use of antidiabetic biguanides for cancer prevention and treatment: results of preclinical studies].

The critical analysis of preclinical testing of anticarcinogenic and antitumor activity of biguanides presented in this paper. Experiments have been conducted using in total more than 20 models of carcinogenesis including models of spontaneous , chemically- , radiation- and virus-induced carcinogenesis, as well as carcinoigenesis induced by special fat diets and by genetic modification in rodents. Cancer preventive effect of buiguanides has been studied in relation to total tumor incidence and to 17 target organs in animals of 3 species, including 25 various strains of mice, 4 strains of rats and 1 strain of hamsters using various routs of administration and doses. In the majority of cases (86%) the exposure to biguanides leads to inhibition of carcinogenesis. In 14% of the cases inhibitory effect of the drugs was not observed, however there was no any case of stimulation of carcinogenesis by antidiabetic biguanides., Metformin suppressed tumor growth in the majority of in vitro studies conducted in 46 different cell lines originated from malignant tumors of 15 localization as well as in athymic mice with xenografts of 31 tumor lines. It was concluded that there are sufficient experimental evidences of anticarcinogenic and antitumor effects of antidiabetic biguanides revealed in a number of models of induced and spontaneous carcinogenesis.

[Age dynamics of angiogenesis markers in transgenic HER-2/neu (FBV/N) mammary adenocarcinoma-prone mice].

Age-dependent angiogenesis intensity changes have been studied in transgenic HER-2/neu (FBV/N) mice characteristic of breast tumors' high incidence with hyperexpression of HER-2/neu. Concentration of vascular endothelial growth factor, insulin-dependent growth factor 1, nitrogen monoxide, tissue plasminogen activator and type 1 plasminogen activator inhibitor were assessed by means of immune-enzyme assay. The results testify to angiogenesis processes activation side by side with aging and growth of the tumors. Maximum manifestation of these disturbances (growth factors' blood concentrations increase and endotheliocytes' functional activity inhibition) has been revealed in 6-month-old mice during neoplasma maximum intensive and aggressive growth period.

[The effect of SSH&H on the lifespan and spontaneous cancer development in transgenic mice with HER-2/neu mutation].

10 months old mice receiving SSH&H with daily food increased the lifespan in comparison to the control group. The maximal lifespan was increased by 1,6 months. For the long-living 10% group the mean lifespan increased by 8,7% compared to the control group (p<0,05). The mammary gland neoplasia rate was the same in both groups. The mean latent tumor development period duration, number and size of the tumors were also similar. There was a tendency to lower lung metastases rate in the experimental group. The cumulative neoplastic frequency curve for the experimental group was shifted to the right in comparison to the control group curve giving evidence to the inhibitory effect of SSH&H on the neoplastic rate in transgenic mice with HER-2/neu mutation.

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 5. SkQ1 prolongs lifespan and prevents development of traits of senescence.

Very low (nano- and subnanomolar) concentrations of 10-(6'-plastoquinonyl) decyltriphenylphosphonium (SkQ1) were found to prolong lifespan of a fungus (Podospora anserina), a crustacean (Ceriodaphnia affinis), an insect (Drosophila melanogaster), and a mammal (mouse). In the latter case, median lifespan is doubled if animals live in a non-sterile vivarium. The lifespan increase is accompanied by rectangularization of the survival curves (an increase in survival is much larger at early than at late ages) and disappearance of typical traits of senescence or retardation of their development. Data summarized here and in the preceding papers of this series suggest that mitochondria-targeted antioxidant SkQ1 is competent in slowing down execution of an aging program responsible for development of age-related senescence.

Metformin decelerates aging and development of mammary tumors in HER-2/neu transgenic mice.

Transgenic FVB/N female mice carrying HER-2/neu mammary cancer gene received metformin (1200 mg/liter) with drinking water 5 days a week starting from the age of 2 months until natural death. Metformin slightly reduced food consumption, but did not change water consumption and dynamics of weight gain. Mean life span of mice increased by 8% (p<0.05), in 10% long-living mice it was prolonged by 13.1%, and the maximum life span was prolonged by 1 month under the effect of metformin in comparison with the control. The rate of populational aging decreased by 2.26 times. The total incidence of mammary adenocarcinoma and their multiplicity did not change under the effect of metformin, while the latency of tumor development increased and the mean diameter of tumors decreased. Hence, we first demonstrated a geroprotective effect of metformin and its suppressive effect towards the development of mammary tumors.

[Effect of antidiabetic drug diabenol on parameters of biological age, life span and tumor development in NMRI and HER-2/neu mice]. / Vliianie antidiabeticheskogo preparata diabenol na pokazateli biologicheskogo vozrasta, prodolzhitel'nost' zhizni i razvitie novoobrazovanii u myshei NMRI i HER-2/neu.

The effect of new antidiabetic drug Diabenol [9-diethylaminoethyl-2,3-dihydroimidazo-(1,2alpha) benzimidazol dihydrochloride] on life span and spontaneous tumor incidence in NMRI and transgenic HER-2/neu mice was studied. Female NMRI and transgenic HER-2/neu mice were given diabenol with drinking water (0.1 mg/l=approx. 10 mg/kg of b.w.) 5 times a week since the age of 2 months until natural death. The treatment with the drug failed influence body weight gain dynamics, food and water consumption and the body temperature in NMRI mice. Diabenol treatment slowed down age-related disturbances in estrous function and increased life span of all and 10% most long-living NMRI mice. The treatment with diabenol inhibited spontaneous tumor incidence (mammary gland and lymphomas mainly) and increased the mammary tumor latency. Dibenol treatment slowed down age-related changes in estrous function in HER-2/neu mice, failed influence survival of these mice and slightly inhibited the incidence and decreased the size of mammary adenocarcinoma metastases into the lung. Thus, long-term treatment with diabenol is safe and non-toxic in mice. The drug increases survival and inhibits spontaneous carcinogenesis in mice