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Published on: July 16, 2017
Quantitative Structure-Cytotoxicity Relationship of Pyrano[4,3-b]chromones
Junko Nagai1, Haixia Shi2,3, Yuka Kubota4
1Department of Medical Molecular Informatics, Meiji Pharmaceutical University, Tokyo, Japan.
Background/Aim:
4H-1-Benzopyran-4-one (chromone) provides a backbone structure for the chemical synthesis of potent anticancer drugs. Since studies of the biological activity of pyrano[4,3-b]chromones are limited, we investigated a total of 20 pyrano[4,3-b]chromones (10 sets of diastereomers) for their cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and human normal oral cells, and then carried out a quantitative structure-activity relationship (QSAR) analysis.
Materials And Methods:
Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Tumor-specificity (TS) was evaluated by the ratio of mean 50% cytotoxic concentration (CC50) against normal oral cells to that against human OSCC cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by the CC50 against tumor cells. Apoptosis induction was evaluated by morphological observation, western blot analysis and cell-cycle analysis. For QSAR analysis, a total of 3,072 physicochemical, structural and quantum chemical features were calculated from the most stabilized structure optimized using CORINA.
Results:
8-Chloro-4,4a-dihydro-3-methoxy-3-methyl-3H,10H-pyrano[4,3-b][1]benzopyran-10-one (16) and 3-ethoxy-4,4a-dihydro-8-methoxy-3H,10H-pyrano[4,3-b][1]benzopyran-10-one (17) had the highest TS, higher than that of 5-flurouracil and melphalan, without induction of apoptosis. Compound 16 induced cytostatic growth inhibition and much lower cytotoxicity against human normal oral keratinocytes compared to doxorubicin. TS of 20 pyrano[4,3-b]chromones was correlated with 3D structure, polarity, ionic potential and electric state.
Conclusion:
Chemical modification of 16 may be a potential choice for designing a new type of anticancer drug.
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