MSN8C: A Promising Candidate for Antitumor Applications as a Novel Catalytic Inhibitor of Topoisomerase II.

MSN8C, an analog of mansonone E, has been identified as a novel catalytic inhibitor of human DNA topoisomerase II that induces tumor regression and differs from VP-16(etoposide). Treatment with MSN8C showed significant antiproliferative activity against eleven human tumor cell lines in vitro. It was particularly effective against the HL-60/MX2 cell line, which is resistant to Topo II poisons. The resistance factor (RF) of MSN8C for Topo II in HL-60/MX2 versus HL-60 was 1.7, much lower than that of traditional Topo II poisons. Furthermore, in light of its potent antitumor efficacy and low toxicity, as demonstrated in the A549 tumor xenograft model, MSN8C has been identified as a promising candidate for antitumor applications.

Curcumin and its nano-formulations: Defining triple-negative breast cancer targets through network pharmacology, molecular docking, and experimental verification.

Background: Curcumin (CUR) displays the capability of suppressing the proliferation and metastasis of various cancer cells. However, the effects and underline mechanisms of CUR to treat triple-negative breast cancer (TNBC) have not been systematically elucidated with an appropriate method. Methods: In the present research, a combination method of network pharmacology, molecular docking, and in vitro bio-experiment was used to investigate the pharmacological actions and underline mechanisms of CUR against TNBC. First, common targets of CUR and TNBC were screened via Venny 2.1.0 after potential CUR-related targets and targets of TNBC were got from several public databases. Then, the Gene Ontology (GO) function and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed on the Metascape website, and the network of compound-targets-pathways was constructed via Cytoscape software. Moreover, the network of protein-protein interaction was constructed by the STRING database to screen potential targets. Moreover, molecular docking was applied to affirm the interaction of CUR with the screened top 10 potential targets. Finally, in vitro experiments were used to further verify the effects and mechanisms of CUR and its nano-formulation (CUR-NPs) against TNBC. Results: Forty potential targets of CUR against TNBC were obtained. STAT3, AKT1, TNF, PTGS2, MMP9, EGFR, PPARG, NFE2L2, EP300, and GSK3B were identified as the top 10 targets of CUR against TNBC. In vitro experiment verified that CUR and CUR-NPs could not only restrain the invasion, migration, and proliferation of MDA-MB-231 cells but also induce their apoptosis. In addition, molecular docking demonstrated that CUR could bind spontaneously with the screened top 10 targeted proteins, and a real-time PCR experiment demonstrated that both CUR and CUR-NPs could downregulate the genetic expression levels of the 10 targets. Moreover, according to the CUR-targets-pathways network, PI3K-Akt, EGFR tyrosine kinase inhibitor resistance, JAK-STAT, Foxo, and HIF-1 signaling pathways were identified as the important pathways of CUR effects on TNBC. Among them, the inhibiting effects of CUR and CUR-NPs on the JAK-STAT signaling pathway were further verified by the western blot analysis. Conclusion: Taken together, the present research demonstrates that CUR and CUR-NPs have pharmacological effects against TNBC via a multi-target and multi-pathway manner.

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.

Developing an isotope dilution UHPLC-MS/MS method to quantify linezolid in human plasma: application to therapeutic drug monitoring.

Aim: To optimize clinical efficacy and reduce the drug-exposure-related toxicity of linezolid, whose concentrations show wide inter-variabilities, a simple and reliable quantitative assay for therapeutic drug monitoring is necessary. Results: A UHPLC-MS/MS assay has been established for determination of linezolid in human plasma and fully validated according to the US FDA guidelines. After a simple, isotope-dilluted precipitation with methanol, the analytes were separated by a straightforward isocratic mode and the MS/MS was conducted under the ESI+ mode fitted with SRM. The calibration curves proved acceptable linearity in the range of 0.1-30.0 µg/ml. Conclusion: The present assay is currently used in routine clinical practice, being applied to therapeutic drug monitoring and helps to optimize individual dosing regimens and manage adverse effects in ICU patients.

Amphiphilic Copolymeric Micelles for Doxorubicin and Curcumin Co-Delivery to Reverse Multidrug Resistance in Breast Cancer.

Development of multidrug resistance against chemotherapeutic drugs is one of the major obstacles to successful cancer therapy in the clinic. Thus far, amphiphilic polymeric micelles and chemosensitizers have been used to overcome multidrug resistance in cancer. The goals of this study were to prepare poly(ethylene glycol)-bock-poly(lactide) (PEG(2k)-PLA(5k)) micelles for co-delivery of the chemotherapeutic drug doxorubicin (DOX) with a chemosensitizer curcumin (CUR), investigate the potential of the dual drug-loaded micelles ((DOX+CUR)-Micelles) to reverse multidrug resistance, and explore the underlying mechanisms. (DOX + CUR)-Micelles were prepared using an emulsion solvent evaporation method. The cellular uptake, drug efflux, down-regulation of P-glycoprotein expression and inhibition of ATP activity of (DOX+ CUR)-Micelles were studied in drug-resistant MCF-7/ADR cells. In vitro analyses demonstrated that (DOX + CUR)-Micelles were superior to free DOX, free drug combination (DOX + CUR), and DOX-loaded micelles in inhibiting proliferation of MCF-7/ADR cells. This effect of (DOX + CUR)-Micelles was partially attributable to their highest cellular uptake, lowest efflux rate of DOX, and strongest effects on down-regulation of P-glycoprotein and inhibition of ATP activity. Additionally, (DOX+CUR)-Micelles showed increased tumor accumulation and strong inhibitory effect on tumor growth in the xenograft model of drug-resistant MCF-7/ADR cells compared to that of other drug formulations. These results indicate that (DOX + CUR)-Micelles display potential for application in the therapy of drug-resistant breast carcinoma.

Quercetin and doxorubicin co-encapsulated biotin receptor-targeting nanoparticles for minimizing drug resistance in breast cancer.

The combination of a chemotherapeutic drug with a chemosensitizer has emerged as a promising strategy for cancers showing multidrug resistance (MDR). Herein we describe the simultaneous targeted delivery of two drugs to tumor cells by using biotin-decorated poly(ethylene glycol)-b-poly(ε-caprolactone) nanoparticles encapsulating the chemotherapeutic drug doxorubicin and the chemosensitizer quercetin (BNDQ). Next, the potential ability of BNDQ to reverse MDR in vitro and in vivo was investigated. Studies demonstrated that BNDQ was more effectively taken up with less efflux by doxorubicin-resistant MCF-7 breast cancer cells (MCF-7/ADR cells) than by the cells treated with the free drugs, single-drug-loaded nanoparticles, or non-biotin-decorated nanoparticles. BNDQ exhibited clear inhibition of both the activity and expression of P-glycoprotein in MCF-7/ADR cells. More importantly, it caused a significant reduction in doxorubicin resistance in MCF-7/ADR breast cancer cells both in vitro and in vivo, among all the groups. Overall, this study suggests that BNDQ has a potential role in the treatment of drug-resistant breast cancer.

3D-QSAR studies of azaoxoisoaporphine, oxoaporphine, and oxoisoaporphine derivatives as anti-AChE and anti-AD agents by the CoMFA method.

In the present study, a series of novel azaoxoisoaporphine derivatives were reported and their inhibitory activities toward acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and Aß aggregation were evaluated. The new compounds remained high inhibitory potency on Aß aggregation, with inhibitory activity from 29.42% to 89.63% at a concentration of 10µM, but had no action on AChE or BuChE, which was very different from our previously reported oxoaporphine and oxoisoaporphine derivatives. By 3D-QSAR studies, we constructed a reliable CoMFA model (q(2)=0.856 and r(2)=0.986) based on the inhibitory activities toward AChE and discovered key information on structure and anti-AChE activities among the azaoxoisoaporphine, oxoaporphine, and oxoisoaporphine derivatives. The model was further confirmed by the test-set validation (q(2)=0.873, r(2)=0.937, and slope k=0.902) and Y-randomization examination. The statistically significant and physically meaningful 3D-QSAR/CoMFA model provided better insight into understanding the inhibitory behaviors of those chemicals, which may provide useful information for the rational molecular design of azaoxoisoaporphine derivatives anti-AChE and anti-AD agents.

Synthesis and evaluation of mansonone F derivatives as topoisomerase inhibitors.

A series of mansonone F (MF) derivatives were designed and synthesized. These compounds were found to be strong inhibitors for topoisomerases, with much more significant inhibition for topoisomerase II rather than topoisomerase I. The best inhibitor showed 20 times stronger anti-topoisomerase II activity than a positive control Etoposide. The cytotoxic activity of these MF derivatives was evaluated against human cancer cell lines CNE-2 and Glc-82, which showed that these compounds were potent antitumor agents. The structure-activity relationships (SARs) study revealed that o-quinone group and pyran ring are important for their cytotoxic activity.