Discovery of novel tacrine derivatives as potent antiproliferative agents with CDKs inhibitory property.

Tacrine was the first approved drug by the FDA for the treatment of Alzheimer's disease (AD) but was withdrawn from the market due to its dose-dependent hepatotoxicity. Herein, we describe our efforts toward the discovery of a novel series of tacrine derivatives for cancer therapeutics. Intensive structural modifications of tacrine led to the identification of N-(4-{9-[(3S)-3-aminopyrrolidin-1-yl]-5,6,7,8-tetrahydroacridin-2-yl}pyridin-2-yl)cyclopropanecarboxamide hydrochloride ((S)-45, ZLWT-37) as a potent antiproliferative agent (GI50 = 0.029 µM for HCT116). In addition, ZLWT-37 exhibited lower inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) compared to tacrine. The in vitro studies demonstrated that ZLWT-37 could significantly induce apoptosis and arrest the cell cycle in the G2/M phase in HCT116 cells. The in vivo studies revealed that compound ZLWT-37 showed excellent antitumor efficacy in HCT116 xenograft tumor model and favorable pharmacokinetics profiles (F% = 28.70%) as well as low toxicity in the acute toxicity test with a median lethal dose (LD50) of 380.3 mg/kg. Encouragingly, ZLWT-37 had no obvious hepatotoxicity, nephrotoxicity, and hematologic toxicity. Kinase assay suggested that ZLWT-37 possessed potent cyclin-dependent kinase 9 (CDK9) inhibitory activity (IC50 = 0.002 µM) and good selectivity over CDK2 (IC50 = 0.054 µM). Collectively, these findings indicate that compound ZLWT-37 is a promising anti-cancer agent that deserves further preclinical evaluation.

Design, synthesis, and biological evaluation of ß-carboline 1,3,4-oxadiazole based hybrids as HDAC inhibitors with potential antitumor effects.

A series of novel ß-carboline 1,3,4-oxadiazole based hybrids were designed, synthesized, and tested for cytotoxicity and HDAC inhibition. Among the target compounds, compound ZDLT-1 displayed high inhibitory activity for class I HDACs 1, 2, and 3, and potent anti-proliferative activity against HCT116 cells with an IC50 value of 0.173 ± 0.018 µM, it also exhibited better inhibitory activity with an IC50 value of 6 nM for HDAC6 than SAHA (IC50 = 15 nM). Furthermore, the pharmacological experiment of Hoechst staining, colony formation, cell apoptosis assay, and wound healing scratch assay indicated that compound ZDLT-1 was a potent cytotoxic agent against HCT116 cells with cell apoptosis induction. Further, in silico prediction of physicochemical properties, drug-likeness, and ADME parameters suggested that compound ZDLT-1 is a promising anticancer agent. Taken together, the high potency cytotoxicity and class I HDACs inhibitory activity of compound ZDLT-1, which with the ß-carboline 1,3,4-oxadiazole based hybrids as potent anticancer agents could be nominated for further modification and optimization.

Facile synthesis of C1-substituted ß-carbolines as CDK4 inhibitors for the treatment of cancer.

Cyclin-dependent kinase 4 (CDK4), which is involved in dynamic regulation of cell cycle, has gained particularly attention for its role in controlling tumor growth.Increasing evidence showed that ß-carboline derivatives have the potential to inhibit CDK4. Herein, on the basis of previous work, we designed and synthesized a series of novel ß-carbolines and evaluated their antitumor activity.Among them, compounds ZDLD13 and ZDLD20, with the most potent anti-proliferative activity and CDK4 enzymatic inhibition activity, were selected for further pharmacological research in vitro and in vivo. The results in vitro showed that ZDLD13 and ZDLD20 exhibited potent anti-HCT116 activityincluding inhibition of colony formation, inhibition of invasion and migration, inducing of apoptosis, and arresting of G1 phase in cell cycle.In vivo,ZDLD13showed significant tumor growth inhibition in HCT116 tumor xenograft model without causing significant weight loss and toxicityconsistent with the acute toxicity test. In addition, silico study showed ZDLD13 and ZDLD20 not only have good biological actions, but also acceptable predicted ADME and physicochemical properties.Taken together, compoundsZDLD13and ZDLD20 could be selected for further modification and preclinical evaluation.