9-Bromo-2,3-diethylbenzo[de]chromene-7,8-dione (MSN54): A novel non-intercalative topoisomerase II catalytic inhibitor.

Novel mansonone F derivative MSN54 (9-bromo-2,3-diethylbenzo[de]chromene-7,8-dione) exhibited significant cytotoxicity against twelve human tumor cell lines in vitro, with particularly strong potency against HL-60/MX2 cell line resistant to Topo II poisons. MSN54 was found to have IC50 of 0.69 and 1.43 µM against HL-60 and HL-60/MX2 cells, respectively. The resistance index is 10 times lower than that of the positive control VP-16 (etoposide). Various biological assays confirmed that MSN54 acted as a Topo IIα specific non-intercalative catalytic inhibitor. Furthermore, MSN54 exhibited good antitumor efficacy and low toxicity at a dose of 5 mg/kg in A549 tumor xenograft models. Thus, compound MSN54 is a promising candidate for the development of novel antitumor agents.

Design, synthesis and biological evaluation of novel perimidine o-quinone derivatives as non-intercalative topoisomerase II catalytic inhibitors.

For the development of novel anticancer agents, we designed and synthesized a total of 37 perimidine o-quinone derivatives containing the o-quinone group at the A or B ring and different substituents (alkyl groups, aryl groups or heterocycles) at the C ring of the compounds. The structure-activity relationships (SARs) were established based on the cytotoxicity data of compounds from the HL-60, Huh7, Hct116, and Hela cell lines. The cytotoxicity results showed that most compounds exhibited potent cytotoxicity. In particular, compound b-12 showed the best anti-proliferative activity (IC50 ≤ 1 µM) against four cancer cell lines and strong potency against the HL-60/MX2 (0.47 µM) cell line, which is resistant to Topo II poisons. Further studies showed that b-12 exhibited potent Topo IIα inhibitory activity (IC50 = 7.54 µM) compared with Topo I, which acted as a class of non-intercalative Topo IIα catalytic inhibitor by inhibiting the ATP binding site of Topo II. Cell apoptosis and cell cycle assays confirmed that b-12 could induce the apoptosis of Huh7 cells in a dose-dependent manner.

A colorimetric and fluorescent dual probe for palladium in aqueous medium and live cell imaging.

A colorimetric and fluorescent dual probe for palladium species was rationally developed by combining the resorufin fluorophore with allyl chloroformate. The probe enables the visual detection of palladium based on its vivid color change from pale yellow to pink and its fluorescence off-on response to palladium in PBS solution. The detection limit was calculated to be as low as 2.1 nM. The live cell imaging results showed that this probe could be used as an effective fluorescent probe for detecting intracellular palladium species. All these results featured its promising application prospects in the palladium analytical field.

Synthesis and biological evaluation of benzo[a]phenazine derivatives as a dual inhibitor of topoisomerase I and II.

Topoisomerases (Topo I and Topo II) are very important players in DNA replication, repair, and transcription, and are a promising class of antitumor target. In present study, a series of benzo[a]phenazine derivatives with alkylamino side chains at C-5 were designed, synthesized, and their biological activities were evaluated. Most of derivatives showed good antiproliferative activity with a range of IC50 values of 1-10 µM on the four cancer cell lines HeLa, A549, MCF-7, and HL-60. Topoisomerase-mediated DNA relaxation assay results showed that derivatives could effectively inhibit the activity of both Topo I and Topo II, and the structure-activity relationship studies indicated the importance of introducing an alkylamino side chain. Further mechanism studies revealed that the compounds could stabilize the Topo I-DNA cleavage complexes and inhibit the ATPase activity of hTopo II, indicating that they are a rare class of dual topoisomerase inhibitors by acting as Topo I poisons and Topo II catalytic inhibitors. Moreover, flow cytometric analysis and caspase-3/7 activation assay showed that this class of compounds could induce apoptosis of HL-60 cells.

Disubstituted 1,8-dipyrazolcarbazole derivatives as a new type of c-myc G-quadruplex binding ligands.

A series of 1,8-dipyrazolcarbazole (DPC) derivatives (6a-6d, 7a-7d) designed as G-quadruplex ligands have been synthesized and characterized. The FRET-melting and SPR results showed that the DPC derivatives could well recognize G-quadruplex with strong discrimination against the duplex DNA. In addition, the DPC derivatives showed much stronger stabilization activities and binding affinities for c-myc G-quadruplex rather than telomeric G-quadruplex. Therefore, their interactions with c-myc G-quadruplex were further explored by means of CD spectroscopy, PCR-stop assay, and molecular modeling. In cellular studies, all compounds showed strong cytotoxicity against cancer cells, while weak cytotoxicity towards normal cells. RT-PCR assay showed that compound 7b could down-regulate c-myc gene expression in Ramos cell line, while had no effect on c-myc expression in CA46 cell line with NHE III(1) element removed, indicating its effective binding with G-quadruplex on c-myc oncogene in vivo.

Key quality factors for Chinese herbal medicines entering the EU market.

Chinese herbal medicines (CHMs) have unique advantages in the prevention and treatment of diseases, which are widely recognized in the world. More and more CHMs are becoming increasingly popular in the international markets. However, the quality control of CHMs is a significant issue for their acceptance and recognition in the international market. This review mainly focuses on the quality requirements for CHMs to enter the European Union (EU) market. Both Chinese and European regulations and quality controls are compared. Firstly, the EU medicinal regulatory system and relevant regulations were reviewed. Secondly, the key factors of the quality control of CHMs, including Chinese herbal drugs, extracts and products were compared with those of European herbal medicines in the EU market. Subsequently, three main registration routes for herbal medicinal products including Chinese herbal medicinal products entering the EU were introduced. Furthermore, the legal status of traditional Chinese medicine granules in the EU was also discussed. Through the comparison of the key quality factors for CHMs in China and the EU, the similarities and differences in terms of quality requirements and regulations are addressed, which provides a reference for the development of CHMs into the EU market.

Network pharmacology-based identification for therapeutic mechanism of Ling-Gui-Zhu-Gan decoction in the metabolic syndrome induced by antipsychotic drugs.

BACKGROUND: The metabolic syndrome (MetS) is a common side effect of second-generation antipsychotic drugs (SGAs), leading to poor prognosis in patients with mental illness. The traditional Chinese herbal formula Ling-Gui-Zhu-Gan decoction (LGZGD) is a clinically validated remedy for SGAs-induced MetS, but its underlying mechanism remains unclear. METHODS: A network pharmacology-based analysis was performed to explore predicted plasma-absorbed components, putative therapeutic targets, and main pathways involved in LGZGD bioactivity. We constructed a target interaction network between the predicted targets of LGZGD and the known targets of MetS, after which we extracted major hubs using topological analysis. Thereafter, the maximum value of "edge betweenness" of all interactions was defined as a bottleneck, which suggested its importance in connecting all targets in the network. Finally, a pathway enrichment analysis of major hubs was used to reveal the biological functions of LGZGD. RESULTS: This approach identified 120 compounds and 361 candidate targets of LGZGD. According to the data generated in this study, the interaction between JUN and APOA1 plays a vital role in the treatment of SGAs-induced MetS using LGZGD. Interestingly, JUN was a putative target of LGZGD and APOA1 is one of the known targets of both MetS and SGAs (olanzapine and clozapine). LGZGD was significantly associated with several pathways including PI3K-Akt signaling, insulin resistance, and MAPK signaling pathway. CONCLUSIONS: LGZGD might inhibit JUN and thereby increases the expression of APOA1 to maintain metabolic homeostasis via some vital pathways.

Design, Synthesis, and Evaluation of Isaindigotone Derivatives To Downregulate c-myc Transcription via Disrupting the Interaction of NM23-H2 with G-Quadruplex.

Transcriptional control of c-myc oncogene is an important strategy for antitumor drug design. G-quadruplexes in the promoter region have been proven to be the transcriptional down-regulator of this gene. The transcriptional factor NM23-H2 can reactivate c-myc transcription by unwinding the G-quadruplex structure. Thus, down-regulation of c-myc transcription via disrupting G-quadruplex-NM23-H2 interaction might be a potential approach for cancer therapy. Here, a series of new isaindigotone derivatives were designed and synthesized based on our previous study. The abilities of these derivatives on interacting with G-quadruplexes or NM23-H2, and disrupting G-quadruplex-NM23-H2 interaction were evaluated. Among these derivatives, 19d and 22d showed remarkable abilities on disrupting G-quadruplex-NM23-H2 interaction. They exhibited significant effects on c-myc-relating processes in SiHa cells, including inhibiting the transcription and translation, inhibiting cellular proliferation, inducing apoptosis, and regulating cell cycle. Our findings provided the basis for the anticancer strategy based on c-myc transcriptional regulation via small molecules disrupting G-quadruplex-protein interaction.

Blocking the binding of WT1 to bcl-2 promoter by G-quadruplex ligand SYUIQ-FM05.

At present, wt1, a Wilms' tumor suppressor gene, is recognized as a critical regulator of tumorigenesis and a potential therapeutic target. WT1 shows the ability to regulate the transcription of bcl-2 by binding to a GC-rich region in the promoter, which can then fold into a special DNA secondary structure called the G-quadruplex. This function merits the exploration of the effect of a G-quadruplex ligand on the binding and subsequent regulation of WT1 on the bcl-2 promoter. In the present study, WT1 was found to bind to the double strand containing the G-quadruplex-forming sequence of the bcl-2 promoter. However, the G-quadruplex ligand SYUIQ-FM05 effectively blocked this binding by interacting with the GC-rich sequence. Our new findings are significant in the exploration of new strategies to block WT1's transcriptional regulation for cancer-cell treatment.

Synthesis and Mechanism Studies of 1,3-Benzoazolyl Substituted Pyrrolo[2,3-b]pyrazine Derivatives as Nonintercalative Topoisomerase II Catalytic Inhibitors.

Novel topoisomerase II (Topo II) inhibitors have gained considerable interest for the development of anticancer agents. In this study, a series of 1,3-benzoazolyl-substituted pyrrolo[2,3-b]pyrazine derivatives were designed, synthesized, and evaluated as potential Topo II catalytic inhibitors. It was found that some of derivatives had good antiproliferative activity on seven cancer cell lines, especially on HL-60/MX2, a cancer cell line derivative from HL-60 that is resistant to Topo II poison. Topo II mediated DNA relaxation assay results showed that derivatives could significantly inhibit the activity of Topo II, and the structure-activity relationship studies indicated the importance of the alkylamino side chain and the benzoazolyl group. Further mechanism studies revealed that derivatives function as Topo II nonintercalative catalytic inhibitors and may block the ATP binding site of Topo II. Moreover, flow cytometric analysis showed that this class of compounds could induce apoptosis of HL-60 cells.

Discovery of Small Molecules for Up-Regulating the Translation of Antiamyloidogenic Secretase, a Disintegrin and Metalloproteinase 10 (ADAM10), by Binding to the G-Quadruplex-Forming Sequence in the 5' Untranslated Region (UTR) of Its mRNA.

Up-regulation of a disintegrin and metalloproteinase 10 (ADAM10) to prevent the formation of ß-amyloid (Aß) peptides might be a promising strategy to treat Alzheimer's disease (AD). RNA G-quadruplex motif within the 5'-UTR of the ADAM10 mRNA is an inhibitory element for ADAM10 translation. Thus, mitigation of the suppressive effect of this motif using an RNA G-quadruplex-forming G-rich sequence (QGRS) binder might be a new approach for AD therapy. Herein, a series of new methylquinolinium derivatives were synthesized and screened by surface plasmon resonance (SPR) and the dual-luciferase reporter assay. Among them, compound 24 showed selective affinity for the QGRS of ADAM10 and could strongly up-regulate the translation of it. Moreover, treatment with 24 led to a significant increase of the secretion of sAPPα, consequently decreasing the Aß40 in cellular. These results illustrate that the interaction between the RNA QGRS and a small molecule may be a new molecular strategy to modulate the translation of ADAM10.

Design, synthesis and biological evaluation of novel 7-alkylamino substituted benzo[a]phenazin derivatives as dual topoisomerase I/II inhibitors.

A novel series of benzo[a]phenazin derivatives bearing alkylamino side chains were designed, synthesized and evaluated for their topoisomerases inhibitory activity as well as cytotoxicity against four human cancer cell lines (HL-60, K-562, HeLa, and A549). These compounds were found to be dual inhibitors of topoisomerase (Topo) I and Topo II, and exhibited excellent antiproliferative activity, in particular against HL-60 cells with submicromolar IC50 values. Further mechanistic studies showed that this class of compounds acted as Topo I poisons by stabilizing the Topo I-DNA cleavage complexes and Topo II catalytic inhibitors by inhibiting the ATPase activity of hTopo II. Molecular docking studies revealed the binding modes of these compounds for Topo I and Topo II.

Synthesis and evaluation of 7,8-dehydrorutaecarpine derivatives as potential multifunctional agents for the treatment of Alzheimer's disease.

A series of 7,8-dehydrorutaecarpine derivatives were synthesized and characterized as potential multifunctional agents for treatment of Alzheimer's disease (AD). All of these synthetic compounds showed high acetylcholinesterase (AChE) inhibitory activity with IC50 values ranged from 0.60 to 196.7 nM, and good selectivity for AChE over butyrylcholinesterase (BuChE) (125- to 3225-fold). A Lineweaver-Burk plot and molecular modeling study indicated these compounds could bind to both catalytic active site and the peripheral anionic site of AChE. Besides, compounds showed higher activity of inhibiting AChE-induced amyloid-beta (Aß) aggregation than curcumin, higher anti-oxidative activity than Trolox, and could also be good metal chelators. Considering their low cytotoxicity, our results indicated that these derivatives provide good templates for developing new multifunctional agents for AD treatment.