No abstract

The cytotoxicity of the natural ent-kaurene diterpenoid, oridonin, has been extensively studied. However, the application of oridonin for cancer therapy was hampered primarily by its moderate potency. In this study, a series of oridonin A-ring modified analogues, and their derivatives bearing various substituents on 14-OH position, were designed, synthesized, and evaluated for anticancer efficacy. Some of the derivatives were significantly more potent than oridonin against both drug-sensitive and drug-resistant cancer cells. The most potent compound, 13p, was 200-fold more efficacious than oridonin in MCF-7 cancer cells. Furthermore, 13p induced apoptosis and cell cycle arrest at the G2/M phase. A decrease in mitochondrial membrane potential and an increase in Bax/Bcl-2 ratio, accompanied by activated caspase-3 cleavage, were observed in MCF-7 cells after treatment with 13p, suggesting that the mitochondrial pathway was involved in the 13p-mediated apoptosis. Moreover, 13p significantly inhibited tumor growth in mouse xenograft models and had no observable toxic effect.

An efficient construction of fused indolines with a 2-quaternary center through a palladium-catalyzed intramolecular Heck reaction of N-(2(2-halobenzoxyl)-2,3-disubstituted indoles is disclosed. This protocol provided a straightforward access to diverse fused indolines with good functional group tolerance.

A series of novel quinoline-chalcone derivatives were designed, synthesized and evaluated for their antiproliferative activity. Among them, compound 24d exhibited the most potent activity with IC50 values ranging from 0.009 to 0.016 μM in a panel of cancer cell lines. Compound 24d also displayed a good safety profile with LD50 value of 665.62 mg/kg by intravenous injection, and its hydrochloride salt 24d-HCl significantly inhibited tumor growth in H22 xenograft models without observable toxic effects, which was more potent than that of CA-4. Mechanism studies demonstrated that 24d bound to the colchicine site of tubulin, arrested cell cycle at the G2/M phase, induced apoptosis, depolarized mitochondria and induced reactive oxidative stress (ROS) generation in K562 cells. Moreover, 24d has potent in vitro anti-metastasis, in vitro and in vivo anti-vascular activities. Collectively, our findings suggest that 24d deserves to be further investigated as a potent and safe anti-tumor agent for cancer therapy.

A Rh(III)-catalyzed annulation between salicylaldehydes and diazo compounds with controllable chemoselectivity is described. AgNTf favored benzofurans via a tandem C-H activation/decarbonylation/annulation process, while AcOH led to chromones through a C-H activation/annulation pathway. The reaction exhibited good functional group tolerance and scalability. Moreover, only a single regioisomer of benzofuran was obtained due to the in situ decarbonylation orientation effect.