Elucidation of structure-activity relationship of 2-quinolone derivatives and exploration of their antitumor potential through Bax-induced apoptotic pathway.

3-Aryl-2-quinolone derivates were extensively investigated for their inhibition of farnesyl transferase. Taking this as a cue, we studied the other possible mechanism of antitumor activity of 2-quinolone derivates. A series of new 2-quinolone derivatives have been synthesized and screened for their cytotoxicity by trypan blue assay on Ehrlich ascites carcinoma cells and MTT assay on MCF-7 cells. Compound 1a (nJST) was found to be more effective in both studies with the lowest CTC(50) value among all nine synthesized compounds. This compound was further screened on four different cell lines, viz. human breast adenocarcinoma (MCF-7, MDA-MB-231), colon cancer (HCT-15), murine melanoma (B16F10) cell lines for 24 and 48 h. The CTC(50) value of the compound was found to be <10 μm. Compound 1a induced DNA damage which was revealed by DNA fragmentation studies and further confirmed by nuclear staining. The compound also showed significant elevation in Bax and reduction Bcl-2 gene expression levels. Acute toxicity study in mice indicated that the compound is safe till 2000 mg/kg. Two different doses 50 and 100 mg/kg were selected and studied in Ehrlich ascites carcinoma model of cancer and have shown significant improvement in survival time and hematological parameters.