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CYP1B1 is implicated to have a role in the development of breast, ovarian, renal, skin and lung carcinomas. It has been suggested that identification of potent and specific CYP1B1 inhibitors can lead to a novel treatment of cancer. Flavonoids have a compact rigid skeleton which fit precisely within the binding cavity of CYP1B1. Systematic isosteric replacement of flavonoid 'O' atom with 'N' atom led to the prediction that a 'quinazoline' scaffold could be the basis for designing potential CYP1B1 inhibitors. A total of 20 quinazoline analogs were synthesized and screened for CYP1B1 and CYP1A1 inhibition in Sacchrosomes™. IC 50 determinations of six compounds with capability of inhibiting CYP1B1 identified quinazolines 5c and 5h as the best candidates for CYP1B1 inhibition, with IC 50 values in the nM range. Further selectivity studies with homologous CYPs, belonging to the CYP1, CYP2 and CYP3 family of enzymes, showed that the compounds are likely to be free from critical drug-drug interaction liability. Molecular modelling studies were performed to rationalize the observed enzymatic inhibitions. Further biological studies in live yeast and human cells, harboring CYP1A1 and CYP1B1 enzymes, have illustrated the most potent compounds' cellular permeability and capability of potently inhibiting CYP1B1 enzyme expressed within live cells., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

The structure of alpha-napthoflavone (ANF), a potent inhibitor of CYP1A1 and CYP1B1, mimics the structure of chalcones. Two potent CYP1B1 inhibitors 7k (DMU2105) and 6j (DMU2139) have been identified from two series of synthetic pyridylchalcones. They inhibit human CYP1B1 enzyme bound to yeast-derived microsomes (Sacchrosomes™) with IC 50 values of 10 and 9 nM, respectively, and show a very high level of selectivity towards CYP1B1 with respect to the IC 50 values obtained with CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2C9 and CYP2C19 Sacchrosomes™. Both compounds also potently inhibit CYP1B1 expressed within 'live' recombinant yeast and human HEK293 kidney cells with IC 50 values of 63, 65, and 4, 4 nM, respectively. Furthermore, the synthesized pyridylchalcones possess better solubility and lipophilicity values than ANF. Both compounds overcome cisplatin-resistance in HEK293 and A2780 cells which results from CYP1B1 overexpression. These potent cell-permeable and water-soluble CYP1B1 inhibitors are likely to have useful roles in the treatment of cancer, glaucoma, ischemia and obesity., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Highly selective CYP1B1 inhibitors have potential in the treatment of hormone-induced breast and prostate cancers. Mimicry of potent and selective CYP1B1 inhibitors, α-naphthoflavone and stilbenes, revealed that two sets of hydrophobic clusters suitably linked via a polar linker could be implanted into a new scaffold 'biphenyl ureas' to create potentially a new class of CYP1B1 inhibitors. A series of sixteen biphenyl ureas were synthesized and screened for CYP1B1 and CYP1A1 inhibition in Sacchrosomes™, yeast-derived recombinant microsomal enzymes. The most active human CYP1B1 inhibitors were further studied for their selectivity against human CYP1A1, CYP1A2, CYP3A4 and CYP2D6 enzymes. The meta-chloro-substituted biphenyl urea 5h was the most potent inhibitor of CYP1B1 with IC 50 value of 5 nM. It displayed excellent selectivity over CYP1A1, CYP1A2, CYP3A4 and CYP2D6 (IC 50 >10 μM in the four CYP assays, indicating >2000-fold selectivity). Similarly, two methoxy-substituted biphenyl ureas 5d and 5e also displayed potent and selective inhibition of CYP1B1 with IC 50 values of 69 and 58 nM, respectively, showing >62 and >98-fold selectivity over CYP1A1, CYP1A2, CYP3A4 and CYP2D6 enzymes. In order to probe if the relatively insoluble biphenyl ureas were cell permeable and if they could at all be used for future cellular studies, their CYP1B1 inhibition was investigated in live recombinant human and yeast cells. Compound 5d displayed the most potent inhibition with IC 50 s of 20 nM and 235 nM, respectively, in the two cell-based assays. The most potent and selective CYP1B1 inhibitor (compound 5h) from Sacchrosomes, also displayed potent inhibition in live cell assays. Molecular modeling was performed to understand the trends in potency and selectivity observed in the panel of five CYP isoenzymes used for the in vitro studies.