Synthesis of scutellarein derivatives with antiproliferative activity and selectivity through the intrinsic pathway

To explore antitumor agents with potent efficacy and low toxicity, scutellarein derivatives with benzoic acid mustard (10a-c, 11a-c and 13a-c) were designed and synthesized. The antiproliferative activities of the target derivatives against A549, MCF-7 and Bel-7402 cancer cell lines were tested. Compound 10a showed the strongest potency with an IC₅₀ value of 1.50 μM against MCF-7 cell line, and displayed low toxicity against human liver L-O2 normal cells (IC₅₀ > 50 μM), showing specificity between normal and malignant cells. The mechanism studies revealed that 10a could induce apoptosis in MCF-7 cells, arrest MCF-7 cell cycle at the G1 phase and cause mitochondrial dysfunction in a concentration-dependant manner. Furthermore, the enhanced expression of the pro-apoptotic proteins caspase-9, caspase-3, Bax and cytochrome c, and the reduced expression of the anti-apoptotic protein Bcl-2 confirmed that 10a induced the intrinsic apoptosis pathway in MCF-7 cells. The potent antiproliferative activity and good selectivity guaranteed 10a a lead compound for the further development into anticancer therapeutics, especially for breast cancer.