Antitumoral activity of liraglutide, a new DNMT inhibitor in breast cancer cells in vitro and in vivo.

Breast cancer (BC) is the most frequently diagnosed female cancer and second leading cause of death. Despite the discovery of many antineoplastic drugs for BC, the current therapy is not totally efficient. In this study, we investigated the potential of repurposing the well-known diabetes type II drug liraglutide to modulate epigenetic modifications in BC cells lines in vitro and in vivo via Ehrlich mice tumors models. The in vitro results revealed a significant reduction on cell viability, migration, DNMT activity and displayed lower levels of global DNA methylation in BC cell lines after liraglutide treatment. The interaction between liraglutide and the DNMT enzymes resulted in a decrease profile of DNA methylation for the CDH1, ESR1 and ADAM33 gene promoter regions and, consequently, increased their gene and protein expression levels. To elucidate the possible interaction between liraglutide and the DNMT1 protein, we performed an in silico study that indicates liraglutide binding in the catalytic cleft via hydrogen bonds and salt bridges with the interdomain contacts and disturbs the overall enzyme conformation. The in vivo study was also able to reveal that liraglutide and the combined treatment of liraglutide and paclitaxel or methotrexate were effective in reducing tumor growth. Moreover, the modulation of CDH1 and ADAM33 mouse gene expression by DNA demethylation suggests a role for liraglutide in DNMT activity in vivo. Altogether, these results indicate that liraglutide may be further analysed as a new adjuvant treatment for BC.

Anti-fatigue activity of an arabinan-rich pectin from acerola (Malpighia emarginata).

A fraction composed of an arabinan-rich pectin was extracted from acerola fruit (Malpighia emarginata) and named ACWS. This fraction presented 93% of total carbohydrate, relative molecular weight of 7.5×104g/mol, galacturonic acid, arabinose, galactose, xylose and rhamnose in 52.1:32.4:7.2:4.8:3.5 molar ratio and had its structure confirmed by NMR analysis. The anti-fatigue activity of ACWS was evaluated using the weight load swim test on trained mice. ACWS was orally administered at doses of 50mg/kg, 100mg/kg and 200mg/kg for 28days. Plasma biochemical parameters, respiration of permeabilized skeletal muscle fibers, and GSH levels and lipoperoxidation in the brain (pre-frontal cortex, hippocampus, striatum and hypothalamus) were determined. ACWS could lengthen the swimming time, increase the plasma levels of glucose, triglycerides, lactate, and the GSH levels in the hippocampus at all tested doses. The mitochondrial respiratory capacity of the skeletal muscle was increased at middle and high ACWS doses. This study provides strong evidence that M. emarginata pectic polysaccharide supplementation has anti-fatigue activity, can modify the kinetics of energy substrates (carbohydrate and fat) mobilization and the respiratory capacity of the skeletal muscle, as well the antioxidant status in the hippocampus of ACWS treated animals.

Effect of omega-3 polyunsaturated fatty acid treatment over mechanical allodynia and depressive-like behavior associated with experimental diabetes.

Neuropathic pain and depression are very common comorbidities in diabetic patients. As the pathophysiological mechanisms are very complex and multifactorial, current treatments are only symptomatic and often worsen the glucose control. Thus, the search for more effective treatments are extremely urgent. In this way, we aimed to investigate the effect of chronic treatment with fish oil (FO), a source of omega-3 polyunsaturated fatty acid, over the mechanical allodynia and in depressive-like behaviors in streptozotocin-diabetic rats. It was observed that the diabetic (DBT) animals, when compared to normoglycemic (NGL) animals, developed a significant mechanical allodynia since the second week after diabetes induction, peaking at fourth week which is completely prevented by FO treatment (0.5, 1 or 3g/kg). Moreover, DBT animals showed an increase of immobility frequency and a decrease of swimming and climbing frequencies in modified forced swimming test (MFST) since the second week after diabetes injection, lasting up at the 4th week. FO treatment (only at a dose of 3g/kg) significantly decreased the immobility frequency and increased the swimming frequency, but did not induce significant changes in the climbing frequency in DBT rats. Moreover, it was observed that DBT animals had significantly lower levels of BDNF in both hippocampus and pre frontal cortex when compared to NGL rats, which is completely prevented by FO treatment. In conclusion, our study demonstrates that FO treatment was able to prevent the mechanical allodynia and the depressive-like behaviors in DBT rats, which seems to be related to its capacity of BDNF level restoration.