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Pharmacological targeting cancer stem cells are emerging as a novel therapeutic modality for cancer treatment and prevention. Human cytochrome P450 enzyme CYP4Z1 represents a promising target for its potential role in attenuating the stemness of breast cancer cells. In order to develop potent and selective CYP4Z1 inhibitors, a series of novel

Evodiamine (Evo) is a quinazolinocarboline alkaloid found in Evodia rutaecarpa and exhibits moderate antiproliferative activity. Herein, we report using a scaffold-hopping approach to identify a series of novel polycyclic heterocyclic derivatives based on Evo as the topoisomerase I (Top1) inhibitor for the treatment of triple-negative breast cancer (TNBC), which is an aggressive subtype of breast cancer with limited treatment options. The most potent compound 7f inhibited cell growth in a human breast carcinoma cell line (MDA-MB-231) with an IC50 value of 0.36 μM. Further studies revealed that Top1 was the target of 7f, which directly induced irreversible Top1-DNA covalent complex formation or induced an oxidative DNA lesion through an indirect mechanism mediated by reactive oxygen species. More importantly, in vivo studies showed that 7f exhibited potent antitumor activity in a TNBC-patient-derived tumor xenograft model. These results suggest that compound 7f deserves further investigation as a promising candidate for the treatment of TNBC.

The acetylcholinesterase (AChE) inhibitors remain key therapeutic drugs for the treatment of Alzheimer's disease (AD). However, the low-safety window limits their maximum therapeutic benefits. Here, a novel kinetics-driven drug design strategy was employed to discover new-generation AChE inhibitors that possess a longer drug-target residence time and exhibit a larger safety window. After detailed investigations, compound 12 was identified as a highly potent, highly selective, orally bioavailable, and brain preferentially distributed AChE inhibitor. Moreover, it significantly ameliorated cognitive impairments in different mouse models with a lower effective dose than donepezil. The X-ray structure of the cocrystal complex provided a precise binding mode between 12 and AChE. Besides, the data from the phase I trials demonstrated that 12 had good safety, tolerance, and pharmacokinetic profiles at all preset doses in healthy volunteers, providing a solid basis for its further investigation in phase II trials for the treatment of AD.

Triple-negative breast cancer (TNBC) is one of the most highly invasive and metastatic breast cancers without safe and effective therapeutic drugs. The natural product oridonin is reported to be a potential anti-TNBC agent. However, its moderate activity and complex structure hampered its clinical application. In this study, the novel oridonin analogues were first identified by removal of multiple hydroxyl groups and structural simplification of oridonin. The representative analogue 20 exhibited potent anticancer effects. Further structural modification on 20 generated the most potent derivative 56, which possessed 120-fold more potent antiproliferative activity than oridonin in the TNBC cell line HCC1806. Importantly, compound 56 exhibited more potent anticancer activity than paclitaxel in TNBC xenograft nude mice. Moreover, 56 could attenuate the expression of MMP-2, MMP-9, p-FAK, and integrin β1 to inhibit TNBC cell metastasis. All results suggest that compound 56 may warrant further investigation as a promising candidate agent for the treatment of TNBC.

[Image: see text] 23-Hydroxybetulinic acid (23-HBA) is a complex lupane triterpenoid, which has attracted increasing attention as an anticancer agent. However, its detailed mechanism of anticancer action remains elusive so far. To reveal its anticancer mode of action, a series of fluorescent 23-HBA derivatives conjugated with coumarin dyes were designed, synthesized, and evaluated for their antiproliferative activities. Subcellular localization and uptake profile studies of representative fluorescent 23-HBA probe 26c were performed in B16F10 cells, and the results suggested that probe 26c was rapidly taken up into B10F10 cells in a dose-dependent manner and mitochondrion was the main site of its accumulation. Further mode of action studies implied that the mitochondrial pathway was involved in 23-HBA-mediated apoptosis. Together, our results provided new clues for revealing the molecular mechanism of natural product 23-HBA for its further development into an antitumor agent.

Oridonin (1) is a complex ent-kaurane diterpenoid exhibiting remarkable antitumor activity. However, the detailed mechanism or cellular target that underlies this activity has not yet been identified. Herein, we report an efficient approach for exploring the anticancer mechanism of oridonin through development of the potent fluorescent analogues. A series of novel fluorescent oridonin probes linked with coumarin moieties were designed, synthesized, and characterized. Fluorescence microscopy and confocal imaging studies suggested that fluorescent oridonin probe 17d was rapidly taken up into tumor cells and the mitochondrion was the main site of its accumulation. Moreover, we confirmed that cytochrome c played an important role in oridonin induced mitochondrion-mediated apoptosis and α,β-unsaturated ketone is the active moiety of oridonin, which is crucial to its uptake, localization, and cytotoxicity. Our results provide new insights on the molecular mechanism of oridonin and would be useful for its further development into an antitumor agent.