Coumarin-Based Aldo-Keto Reductase Family 1C (AKR1C) 2 and 3 Inhibitors

Area of Science:

• Medicinal Chemistry
• Enzymology
• Cancer Biology

Background:

• Aldo-keto reductase family 1C (AKR1C) enzymes are overexpressed in various cancers, contributing to drug resistance.
• Targeting AKR1C enzymes presents a strategy to overcome chemotherapy resistance.

Purpose of the Study:

• To synthesize and characterize novel 7-substituted coumarin derivatives as AKR1C inhibitors.
• To evaluate the potential of these inhibitors as radiosensitizers and chemotherapy potentiators in cancer models.

Main Methods:

• Synthesis of 7-hydroxy coumarin ethyl esters and amides.
• Enzyme inhibition assays to determine IC50 values for AKR1C isoforms.
• Assessment of metabolic stability and half-life in liver microsomes and plasma.
• Evaluation of compound 3a as a radiation sensitizer in prostate cancer cells.
• Testing compound 3a and a selective AKR1C3 inhibitor (K90) for potentiation of chemotherapy cytotoxicity in leukemia cell lines.

Main Results:

• Coumarin amide 3a demonstrated potent inhibition of AKR1C3 (50 nM) and AKR1C2 (90 nM) with favorable metabolic stability.
• Compound 3a did not exhibit radiosensitizing effects in a prostate cancer model.
• Pan-AKR1C inhibition by 3a did not enhance the cytotoxicity of ABT-737, daunorubicin, or dexamethasone in T-cell ALL and pre-B-cell ALL lines.
• Selective AKR1C3 inhibition by K90 enhanced the cytotoxicity of ABT-737 and daunorubicin in T-cell ALL.

Conclusions:

• The study identified potent pan-AKR1C inhibitors with good drug-like properties.
• The findings suggest that pan-AKR1C inhibition may not be universally effective for overcoming drug resistance.
• Isoform-specific inhibition of AKR1C enzymes might be crucial for potentiating chemotherapy in specific leukemia subtypes.