Study of effects of glycaemic and pharmacological treatment in different cell lines

The Aldo-Keto Reductase (AKR) superfamily comprises a group of enzymes which contributes to detoxify reactive aldehydes and ketons produced during oxidative process and exposure to xenobiotics. These compounds include sugar aldehydes, keto-steroids, keto-prostaglandins, retinals, quinones, and lipid peroxidation products. Due to their central role in detoxification, AKRs are associated with various pathological conditions, including: -Diabetes mellitus, where AKR1B1 is involved in the development of diabetic complications. -Cancer, with several AKRs differently expressed in various tumours that may contribute to resistance to chemotherapeutic drugs. A typical feature of diabetes is the elevated blood glucose level (referred as hyperglycemia), which is known to induce a series of metabolic alterations, particularly on insulin independent tissues. Among all the AKR enzymes, AKR1B1 is the most studied because of its pivotal role in mediating hyperglycemic injury and in the development of secondary diabetic complications. Specifically, AKR1B1 promotes inflammation throughs the products of its enzymatic activity on 3-glutathionyl-4-hydroxynonanal (GS-HNE), namely the 3-glutathionyldihydroxynonane (GS-DHN). Moreover, AKR1B1 represents the first enzymes of polyol pathway, an alternative metabolic route of glucose which leads to sorbitol and fructose accumulation in cells under hyperglycemic conditions. Therefore, its inhibition has been proposed as a potential strategy to counteract inflammation and other complications associated with diabetes. Here, the pharmacological inhibition of AKR1B1 has been tested, in order to elucidate its role in inflammation, at the basis of diabetic complications. On the other hand, AKRs together with oxidoreductase enzymes, participated in phase 1 metabolism of endogenous compounds and xenobiotics bearing carbonylic groups, which are converted to their corresponding alcohol metabolites. Specifically, AKR1A1, AKR1B10, AKR1C3 along with another NADPH-dependent reductase, carbonyl reductase (CBR1), are known for their detoxifying action against a class of chemotherapeutic compounds (e.g. anthracyclines) and consequently associated with chemotherapeutic resistance in cancer. The alcoholic derivative of anthracyclines, indeed, shows reduced cytotoxicity probably due to a better expulsion from the cells, and is also associated with cardiotoxicity. In this study, the inhibition of these enzymes has been investigated, aiming to enhance the therapeutic efficacy of anthracyclines and simultaneously minimizing side effects. Finally, the establishment of a novel daunorubicin-resistant cell line has provided the opportunity to investigate the oxidoreductase profile and resistance mechanisms employed by these resistant cells, revealing significant differences in AKR expression and activity compared to non-resistant cells.