A Concise Total Synthesis of Deoxyschizandrin and Exploration of Its Antiproliferative Effects and those of Structurally Related Derivatives

Schizandrin A can inhibit non‑small cell lung cancer cell proliferation by inducing cell cycle arrest, apoptosis and autophagy

Schizandrin A (SchA) can be extracted from the vine plant Schisandra chinensis and has been reported to confer various biologically active properties. However, its potential biological effects on non‑small cell lung cancer (NSCLC) remain unknown. Therefore, the present study aims to address this issue. NSCLC and normal lung epithelial cell lines were first treated with SchA. Cell viability and proliferation were measured using CellTiter‑Glo Assay and colony formation assays, respectively. PI staining was used to measure cell cycle distribution. Cell cycle‑related proteins p53, p21, cyclin D1, CDK4, CDK6, cyclin E1, cyclin E2, CDK2 and DNA damage‑related protein SOX4 were detected by western blot analysis. Annexin V‑FITC/PI staining, DNA electrophoresis and Hoechst 33342/PI dual staining were used to detect apoptosis. JC‑1 and DCFH‑DA fluorescent dyes were used to measure the mitochondrial membrane potential and reactive oxygen species concentrations, respectively. Apoptosis‑related proteins caspase‑3, cleaved caspase‑3, poly(ADP‑ribose) polymerase (PARP), cleaved PARP, BimEL, BimL, BimS, Bcl2, Bax, caspase‑9 and cleaved caspas‑9 were measured by western blot analysis. Dansylcadaverine was used to detect the presence of the acidic lysosomal vesicles. The expression levels of the autophagy‑related proteins LC3‑I/II, p62/SQSTM and AMPKα activation were measured using western blot analysis. In addition, the autophagy inhibitor 3‑methyladenine was used to inhibit autophagy. SchA treatment was found to reduce NSCLC cell viability whilst inhibiting cell proliferation. Low concentrations of SchA (10‑20 µM) mainly induced G₁/S‑phase cell cycle arrest. By contrast, as the concentration of SchA used increases (20‑50 µM), cells underwent apoptosis and G₂/M‑phase cell cycle a13rrest. As the treatment concentration of SchA increased from 0 to 50 µM, the expression of p53 and SOX4 protein also concomitantly increased, but the expression of p21 protein was increased by 10 µM SchA and decreased by higher concentrations (20‑50 µM). In addition, the mRNA and protein expression levels of Bcl‑like 11 (Bim)EL, BimL and BimS increased following SchA application. SchA induced the accumulation of acidic vesicles and induced a marked increase in the expression of LC3‑II protein, suggsting that SchA activated the autophagy pathway. However, the expression of the p62 protein was found to be increased by SchA, suggesting that p62 was not degraded during the autophagic flux. The 3‑methyladenine exerted no notable effects on SchA‑induced apoptosis. Taken together, results from the present study suggest that SchA exerted inhibitory effects on NSCLC physiology by inducing cell cycle arrest and apoptosis. In addition, SchA partially induced autophagy, which did not result in any cytoprotective effects.

MEG3 is restored by schisandrin A and represses tumor growth in choriocarcinoma cells

Schisandrin A (SchA) has been reported as a multidrug resistance-reversing agent; however, its antitumor effects have been rarely reported. Consequently, we attempted to explore whether SchA per se possesses an antitumor property in choriocarcinoma JEG-3 and BeWo cells and its potential mechanisms. JEG-3, BeWo, and HTR-8/SVneo cells were stimulated with SchA at different concentrations (10-100 μM), and cellular viability was evaluated with Cell Counting Kit-8. After stimulation with SchA, proliferation, apoptosis, migration, and invasion were detected by bromodeoxyuridine assay, Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) method, and a Transwell system, in JEG-3 cells transfected with short hairpin-RNA for maternally expressed 3. Western blot was performed to quantify protein. MEG3 was examined by a quantitative reverse transcription-polymerase chain reaction. MEG3 was downregulated in choriocarcinoma tissues. SchA diminished cellular viability, decreased proliferative activity, inhibited migratory and invasive behaviors, and repressed phosphorylation of regulators of phosphatidylinositol 3 kinase/protein kinase B/nuclear factor κB (PI3K/AKT/NF-κB) signaling cascade in gestational choriocarcinoma cells. MEG3 was upregulated by SchA in JEG-3 and BeWo cells. SchA exhibited little suppressive effects in JEG-3 cells lacking MEG3. Besides, the phosphorylation of transducers was evoked in MEG3-silenced JEG-3 cells despite stimulation with SchA. SchA administration repressed the growth of JEG-3 and BeWo cells by upregulating MEG3. Besides, SchA blocked PI3K/AKT/NF-κB signal cascade by elevating MEG3.

Schizandrin A inhibits proliferation, migration and invasion of thyroid cancer cell line TPC-1 by down regulation of microRNA-429

OBJECTIVE

Schizandrin A (SchA) exerts anticancer potential. However, the effects of SchA on thyroid cancer (TC) have not been clear illuminated. Therefore, we investigated the effects of SchA on TC cell line TPC-1 and the underlying mechanisms.

METHODS

TPC-1 cells were treated with SchA and/or transfected with miR-429 mimic, anti-miR-429 and their corresponding negative controls (NC). Cell viability, proliferation, migration, invasion and cell apoptosis were examined by CCK-8 assay, bromodeoxyuridine, modified two-chamber migration assay, Millicell Hanging Cell Culture and flow cytometry analysis, respectively. The expression of miR-429, p16, Cyclin D1, cyclin-dependent kinases 4 (CDK4), matrix metalloprotein (MMP)-2, MMP-9 and Vimentin was detected by qRT-PCR. All protein expression was examined by western blot.

RESULTS

SchA inhibited cell proliferation, metastasis and induced cell apoptosis. Moreover, SchA negatively regulated miR-429 expression. Treatment with miR-429 mimic and SchA reversed the results led by SchA and NC. Furthermore, the phosphorylation β-catenin, mitogen-activated protein kinase (MEK) and extracellular signal-regulated kinase (ERK) were statistically down-regulated by SchA while co-treatment with miR-429 mimic and SchA led to the opposite trend. Moreover, miR-429 knockdown showed contrary results.

CONCLUSION

SchA inhibits cell proliferation, migration, invasion and inactivates Wnt/β-catenin and MEK/ERK signaling pathways by down regulating miR-429.

Advances in the Synthesis of Lignan Natural Products

Lignans comprise a family of secondary metabolites existing widely in plants and also in human food sources. As important components, these compounds play remarkable roles in plants' ecological functions as protection against herbivores and microorganisms. Meanwhile, foods rich in lignans have revealed potential to decrease of risk of cancers. To date, a number of promising bioactivities have been found for lignan natural products and their unnatural analogues, including antibacterial, antiviral, antitumor, antiplatelet, phosphodiesterase inhibition, 5-lipoxygenase inhibition, HIV reverse transcription inhibition, cytotoxic activities, antioxidant activities, immunosuppressive activities and antiasthmatic activities. Therefore, the synthesis of this family and also their analogues have attracted widespread interest from the synthetic organic chemistry community. Herein, we outline advances in the synthesis of lignan natural products in the last decade.

High content screening of diverse compound libraries identifies potent modulators of tubulin dynamics

Tubulin modulating agents such as the taxanes are among the most effective antimitotic cancer drugs, although resistance and toxicity present significant problems in their clinical use. However, most tubulin modulators are derived from complex natural products, which can make modification of their structure to address these problems difficult. Here, we report the discovery of new antimitotic compounds with simple structures that can be rapidly synthesized, through the phenotypic screening of a diverse compound library for the induction of mitotic arrest. We first identified a compound, which induced mitotic arrest in human cells at submicromolar concentrations. Its simple structure enabled rapid exploration of activity, defining a biphenylacetamide moiety required for activity, A family of analogues was synthesized, yielding optimized compounds that caused mitotic arrest and cell death in the low nanomolar range, comparable to clinically used antimitotic agents. These compounds can be synthesized in 1-3 steps and good yields. We show that one such compound targets tubulin, partially inhibiting colchicine but not vinblastine binding, suggesting that it acts allosterically to the known colchicine-binding site. Thus, our results exemplify the use of phenotypic screening to identify novel antimitotic compounds from diverse chemical libraries and characterize a family of biphenylacetamides (biphenabulins) that show promise for further development.