Identification and bioactivity evaluation of miliusanes from Miliusa sinensis.

Miliusanes are a class of anticancer lead molecules belonging to meroterpenoids with an 18-carbon skeleton isolated from Miliusa plants. A phytochemical study of the plant M. sinensis was carried out to discover new miliusanes with diverse structural features in order to better understand their structure-activity relationship. As a result, 20 compounds including 12 new ones (7-14 and 17-20) belonging to two sub-classes of miliusanes were isolated and identified from the twigs and leaves of this plant. Their structures, including absolute configurations, were determined by spectroscopic analyses and electronic circular dichroism. The absolute stereochemistry of miliusane structures has also been confirmed for the first time through the single crystal X-ray diffraction analysis of miliusol (1). Bioactivity evaluation showed that some of the miliusane isolates potently inhibit cell growth of several human derived cancer cell lines with IC50 values ranging from 0.52 to 23.5 µM. Compound 11 demonstrated more potent cytotoxic activity than the known miliusol (1) in stomach cancer cells though its structure contains an unconjugated 1, 4-diketone system, which added a new structure-activity feature to miliusanes. The preliminary mechanism of action studies revealed that they could be a class of dual cell migration inhibitor and senescence inducer.

Isolation and Anticancer Progression Evaluation of the Chemical Constituents from Bridelia balansae Tutcher.

The dichloromethane extract of the roots of Bridelia balansae Tutcher (Phyllanthaceae) was found to show potential anticancer activity against HCT116 colorectal cancer cell. Our bioassay-guided phytochemical investigation of the roots of B. balansae led to the identification of 14 compounds including seven lignans (1-7), three phenylbenzene derivatives (8-10), two flavanone (11-12), and two triterpenoids (13-14). Among them, 4'-demethyl-4-deoxypodophyllotoxin (1) is the first aryltetralin lignan compound identified from this plant species. In addition, the stereochemistry of 1 was validated by X-ray crystallography for the first time, and its distinguished cytotoxic effect on HCT116 cells with an IC50 value at 20 nM was induced via an apoptosis induction mechanism. Compound 1 could also significantly decrease the migration rate of HCT116 cells, indicating its potential application against cancer metastasis. The western blot analysis showed that 1 has the potential to inhibit cell proliferation and metastasis. Treatment of 1 resulted in the downregulation of matrix metalloproteinases 2 (MMP2) and p-Akt, while p21 was upregulated. Collectively, the present study on the phytochemical and biological profile of B. balansae has determined the plant as a useful source to produce promising anticancer lead compounds.

Corynoxine B derivative CB6 prevents Parkinsonian toxicity in mice by inducing PIK3C3 complex-dependent autophagy.

Increasing evidence shows that autophagy impairment is involved in the pathogenesis and progression of neurodegenerative diseases including Parkinson's disease (PD). We previously identified a natural alkaloid named corynoxine B (Cory B) as a neuronal autophagy inducer. However, its brain permeability is relatively low, which hinders its potential use in treating PD. Thus we synthesized various derivatives of Cory B to find more potent autophagy inducers with improved brain bioavailability. In this study, we evaluated the autophagy-enhancing effect of CB6 derivative and its neuroprotective action against PD in vitro and in vivo. We showed that CB6 (5-40 µM) dose-dependently accelerated autophagy flux in cultured N2a neural cells through activating the PIK3C3 complex and promoting PI3P production. In MPP+-treated PC12 cells, CB6 inhibited cell apoptosis and increased cell viability by inducing autophagy. In MPTP-induced mouse model of PD, oral administration of CB6 (10, 20 mg· kg-1· d-1, for 21 days) significantly improved motor dysfunction and prevented the loss of dopaminergic neurons in the striatum and substantia nigra pars compacta. Collectively, compound CB6 is a brain-permeable autophagy enhancer via PIK3C3 complex activation, which may help the prevention or treatment of PD.

BCL2 promotor methylation and miR-15a/16-1 upregulation is associated with sanguinarine-induced apoptotic death in rat HSC-T6 cells.

Previous studies show that several pathways are involved in sanguinarine-induced apoptotic cell death, including AKT downregulation, inhibition of NF-kB activation, mediation of ROS production, downregulation of anti-apoptosis proteins XIAP and cIAP-1, upregulation of BAX, and downregulation of BCL2. In this study, we found out that the quenching of ROS generation by N-acetyl-l-cysteine (NAC), a scavenger of ROS, reversed sanguinarine-induced apoptosis effects, also we found out that sanguinarine-induced rat hepatic stellate T6 cells (HSC-T6 cells) apoptosis was correlated with the generation of increased ROS, which was followed by the activation of caspase-8 (-3, -6, and -9), and the decreasing in the miltochondrial membrane potential (MMP) and the down-regulation of anti-apoptotic protein Bcl-2. It is not clear whether BCL2's downregulation relates to its promoter methylation and miR-15a/16-1 expression which can bind to BCL2 3'-UTR (un-translation reagon). We showed that sanguinarine-induced down regulation of BCL2 was associated with the increased methylation rate of BCL2 promotor district and the increased expression of miR-15a/16-1. HSC-T6 cells treatment with 5-Aza-2'-deoxycytidine (5'-Aza-CdR) impeded sanguinarine-induced BCL2 promotor district methylation and recovered BCL2's expression. Over expression of BCL2 using pEGFP-N1 vector decreased sanguinarine-induced HSC-T6 cells apoptotic death significantly but not completely. These observations clearly showed that BCL2 down regulation was associated with its promoter methylation and miR-15a/16-1 upregulation in sanguinarine-induced Rat HSC-T6 cells.

[Study on UPLC fingerprint of Xiasangju Granules].

OBJECTIVE: To establish a UPLC fingerprint method of Xiasangju Granules. METHODS: UPLC analysis was performed on a Waters ACQUITY UPLC H-Class system and carried out at 30 °C on a Waters Column ACQUITY UPLC BEH C18 (2.1 mm x 50 mm, 1.7 µm). A binary gradient elution system was composed of acetonitrile (phase A)and 0.5% acetic acid solution (phase B). Detection was performed at the wavelength of 320 nm,the mobile flow rate was at 0.4 mL/min. A matrix including 16 variations (characteristic peaks area)and 12 samples was constructed for similarity evaluation, cluster analysis and principle component analysis. RESULTS: The results showed that the collected samples had a good similarity. A specificity fingerprint was produced and 16 characteristic peaks were designated. 12 samples were divided into 6 groups. CONCLUSION: It is a reliable, available and quick method for quality control of Xiasangju Granules.

A stress response p38 MAP kinase inhibitor SB202190 promoted TFEB/TFE3-dependent autophagy and lysosomal biogenesis independent of p38.

TFEB (transcription factor EB) and TFE3 (transcription factor E3) are "master regulators" of autophagy and lysosomal biogenesis. The stress response p38 mitogen-activated protein (MAP) kinases affect multiple intracellular responses including inflammation, cell growth, differentiation, cell death, senescence, tumorigenesis, and autophagy. Small molecule p38 MAP kinase inhibitors such as SB202190 are widely used in dissection of related signal transduction mechanisms including redox biology and autophagy. Here, we initially aimed to investigate the links between p38 MAP kinase and TFEB/TFE3-mediated autophagy and lysosomal biogenesis. Unexpectedly, we found that only SB202190, rather than several other p38 inhibitors, promotes TFEB and TFE3 to translocate from the cytosol into the nucleus and subsequently enhances autophagy and lysosomal biogenesis. In addition, siRNA-mediated Tfeb and Tfe3 knockdown effectively attenuated SB202190-induced gene expression and lysosomal biogenesis. Mechanistical studies showed that TFEB and TFE3 activation in response to SB202190 is dependent on PPP3/calcineurin rather than on the inhibition of p38 or MTOR signaling, the main pathway for regulating TFEB and TFE3 activation. Importantly, SB202190 increased intracellular calcium levels, and calcium chelator BAPTAP-AM blocked SB202190-induced TFEB and TFE3 activation as well as autophagy and lysosomal biogenesis. Moreover, endoplasmic reticulum (ER) calcium is required for TFEB and TFE3 activation in response to SB202190. In summary, we identified a previously uncharacterized role of SB202190 in activating TFEB- and TFE3-dependent autophagy and lysosomal biogenesis via ER calcium release and subsequent calcium-dependent PPP3/calcineurin activation, leading to dephosphorylation of TFEB and TFE3. Given the importance of p38 MAP kinase invarious conditions including oxidative stress, the findings collectively indicate that SB202190 should not be used as a specific inhibitor for elucidating the p38 MAP kinase biological functions due to its potential effect on activating autophagy-lysosomal axis.

In Vitro and in Vivo Antitumor Effects of Plant-Derived Miliusanes and Their Induction of Cellular Senescence.

Our earliest phytochemical separation of Miliusa sinensis aided us in the isolation of a class of unique miliusanes, which were demonstrated as anticancer lead molecules. In the present study, we isolated 19 miliusanes (1-19), including 11 novel ones (5 and 10-19) from another Miliusa plant ( M. balansae), and synthesized additional derivatives to elucidate the structure-activity relationship of miliusanes. When extrapolated to various carcinoma xenograft mouse models, miliusol (1) and its derivatives 20, 26, and 27 (7.5-40 mg/kg) were demonstrated with tumor inhibitory efficacy comparable or even superior to the mainstay chemotherapeutics paclitaxel or fluorouracil. To gain a molecular insight into their anticancer mechanism, 1-3 (GI50 0.03-4.79) were administered to a wide spectrum of human cancer cell lines, including those with specific drug resistance. We further revealed that the antiproliferative properties of miliusanes in carcinoma cells were highly associated with the p21-dependent induction of cellular senescence.