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Members of the short-chain dehydrogenase/reductase (SDR) and aldo-keto reductase (AKR) superfamilies mediate the reduction of anthracyclines to their less potent C-13 alcohol ...metabolites. This reductive metabolism has been recognized as one of the most important factors that trigger anthracycline resistance in cancer cells. In our study, two purine analogues, purvalanol A and roscovitine, were identified as effective inhibitors of aldo-keto reductase 1C3 (AKR1C3), an enzyme that is overexpressed in many cancer types and is also a key player in tumour cell resistance to anthracyclines. Purvalanol A and roscovitine potently inhibited human recombinant AKR1C3 (Ki = 5.5 μM and 1.4 μM, respectively) and displayed similar activity in experiments with intact cells. Ligand-protein docking calculations suggested that both inhibitors occupied a part of the cofactor-binding site. Furthermore, we demonstrated that the combination of daunorubicin with purvalanol A or roscovitine exhibited a synergistic effect in AKR1C3 overexpressing cells. Based on these findings, it is possible to presume that purvalanol A and roscovitine may have the potential to enhance the therapeutic effectiveness and safety of anthracyclines via inhibition of AKR1C3.
Dinaciclib is a multi-specific cyclin-dependent kinase (CDK) inhibitor with significant preclinical and clinical activity. It inhibits CDK1, CDK2, CDK5, CDK9 and CDK12 in the nanomolar range and ...exhibits potent antiproliferative effects on various cancers in vitro and in vivo. Aldo-keto reductases (AKR) and carbonyl reductases (CBR) are enzymes involved at the biosynthesis, intermediary metabolism and detoxification processes, but can also play a significant role in cancer resistance. Here, we report that dinaciclib is a strong inhibitor of aldo-keto reductase 1C3 (AKR1C3), an enzyme that is known to be an important regulator of cell proliferation and differentiation. AKR1C3 is overexpressed in a range of cancer types and is also involved in tumour cell resistance to anthracyclines. In our study, dinaciclib displayed tight-binding inhibition of human recombinant AKR1C3 (Ki
app
= 0.07 µM) and was also active at the cellular level (IC
50
= 0.23 µM). Dinaciclib acts as a noncompetitive inhibitor with respect to daunorubicin and as an uncompetitive inhibitor with respect to the NADPH. In subsequent experiments, pretreatment with dinaciclib (0.1 µM) significantly sensitized AKR1C3-overexpressing anthracycline-resistant cancer cells to daunorubicin. In conclusion, our results indicate that dinaciclib may potentially increase the therapeutic efficacy and safety of anthracyclines by preventing anthracycline resistance and minimizing their adverse effects.
Charles University Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Michaela Flaxová Supervisor: prof. Ing. Vladimír Wsól, Ph.D. Title of diploma thesis: Study of ...resistance in cancer therapy - protein kinase inhibitors influence on activity of selected human reductases II. Nowadays cancerous diseases are significant problem, and the incidence is still increasing. Anthracycline antibiotics are important in therapy of cancerous diseases, unfortunately, they have serious side effects and drug resistance is often obstacle for the effective treatment. The origin of cardiotoxicity is still not clear, older theories were based on formation of reactive oxygen species (ROS). Nevertheless, newer theories confirm that anthracyclines or their metabolites influence complicated cell pathways. The enzymes, which metabolize anthracyclines, specifically daunorubicin, were the subject of this work. The carbonyl reducing enzymes are NADP(H)-dependent oxidoreductases, which are able to catalyse reduction of aldehydes and ketones to primary and secondary metabolites, daunorubicin is transformed to daunorubicinol directly by this way. Therefore we are most interested in enzymes from aldo-keto reductase family and short-chain dehydrogenases (SDR), namely AKR1C3 and CBR1. Many enzymes...
