Xian-Zhe Dong

Effect of Tenuifoliside A isolated from Polygala tenuifolia on the ERK and PI3K pathways in C6 glioma cells

Tenuifoliside A (TFSA) is a bioactive oligosaccharide ester component of Polygala tenuifolia Wild, a traditional Chinese medicine which was used to manage mental disorders effectively. The neuroprotective and anti-apoptotic effects of TFSA have been demonstrated in our previous studies. The present work was designed to study the molecular mechanism of TFSA on promoting the viability of rat glioma cells C6. We exposed C6 cells to TFSA (or combined with ERK, PI3K and TrkB inhibitors) to examine the effects of TFSA on the cell viability and the expression and phosphorylation of key proteins in the ERK and PI3K signaling pathway. TFSA increased levels of phospho-ERK and phospho-Akt, enhanced release of BDNF, which were blocked by ERK and PI3K inhibitors, respectively (U0126 and LY294002). Moreover, the TFSA caused the enhanced phosphorylation of cyclic AMP response element binding protein (CREB) at Ser133 site, the effect was revoked by U0126, LY294002 and K252a. Furthermore, when C6 cells were pretreated with K252a, a TrkB antagonist, known to significantly inhibit the activity of brain-derived neurotrophic factor (BDNF), blocked the levels of phospho-ERK, phospho-Akt and phosphor-CREB. Taking these results together, we suggested the neuroprotection of TFSA might be mediated through BDNF/TrkB-ERK/PI3K-CREB signaling pathway in C6 glioma cells.

Sanguinarine Inhibits Vascular Endothelial Growth Factor Release by Generation of Reactive Oxygen Species in MCF-7 Human Mammary Adenocarcinoma Cells

The inhibitory action and the possible mechanism of anticancer compound Sanguinarine (SAN) on vascular endothelial growth factor (VEGF) in human mammary adenocarcinoma cells MCF-7 were evaluated in this study. We exposed MCF-7 to SAN for 24 h, then cell viability was assessed by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Human VEGF was measured using a paired antibody quantitative ELISA kit, relative expression of VEGF mRNA was calculated using the real-time PCR studies, and the effect of SAN on the reactive oxygen species (ROS) level was detected by the flow cytometer. Treatment with SAN remarkably inhibited growth of MCF-7 cells and induced cell apoptosis. We found that VEGF release was stimulated by subtoxic concentrations of SAN and inhibited by high dose of SAN, SAN-evoked VEGF release was mimicked by low concentration of H2O2, and SAN-regulated VEGF inhibition was accompanied by increasing of ROS; these changes were abolished by antioxidant. High concentration of SAN inhibited VEGF mRNA expression in MCF-7 cultures, suggesting an effect at transcriptional level, and was also abolished by antioxidant. The present findings indicated that the regulation of VEGF expression and release from MCF-7 cells were possibly through reactive oxygen species evoked by SAN.

A representative prescription for emotional disease, Ding-Zhi-Xiao-Wan restores 5-HT system deficit through interfering the synthesis and transshipment in chronic mild stress-induced depressive rats.

ETHNOPHARMACOLOGICAL RELEVANCE Ding-Zhi-Xiao-Wan (DZ, also known as Kai-Xin-San) is a famous traditional Chinese medicine used for the treatment of emotional disease. Previously, we have found that in a variety of animal models of depression (such as tail suspension model, model of chronic fatigue and forced swimming model) DZ demonstrated significant antidepressant behavior and promoted the production of 5-hydroxytryptamine (5-HT). However, the mechanisms of 5-HT regulation are still unclear. Therefore, the current study is designed to further investigate the antidepressant effect of DZ by observing its influence on 5-HT synthesis, metabolism, transport and other key links, so as to clarify the molecular mechanism of its 5-HT regulation. MATERIALS AND METHODS Solitary rising combined with the chronic unpredictable mild stress (CMS) was used to establish the rat model of depression. The rats were given DZ for 3 weeks, the behavior change and the following items in hippocampus and prefrontal cortex were detected simultaneously: 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), tryptophan hydroxylase (TPH), aromatic amino acid decarboxylase (AADC), monoamine oxidase (MAO) and 5-HT transporter (5-HTT) were observed. RESULTS Our results showed that treatment with the DZ significantly improved the behavior and simultaneously increased the 5-HT level in the hippocampus, prefrontal cortex tissues and hippocampus extracellular of depressive rats. In future studies revealed that DZ could significantly increase the protein and mRNA expression of the key enzymes TPH during the 5-HT synthesis process in the hippocampus and prefrontal cortex of the depressed rats, and suppress the expression of 5-HTT protein and mRNA at the same time. But it had no effects on MAO-A and MAO-B activities. CONCLUSION We believe that antidepressant effect of DZ is caused by the increase of 5-HT synthesis and reduction of 5-HT re-uptake, and eventually increase the content of 5-HT in the brain and the synaptic gaps.

A new triterpenoid saponin from Ardisia gigantifolia

A new triterpenoid saponin, named 3-O-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 3)]-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)]-α-l-arabinopyranosyl-3β,16α,28,30-tetrahydroxy-olean-12-ene (1), along with four known triterpenoids (2–5), was isolated from the rhizomes of Ardisia gigantifolia. Their structures were elucidated by spectroscopic methods. Compounds 1–4 showed cytotoxic activity against Hela, EJ, BCG, and HepG-2 cell lines. The percentage of early apoptotic cells after treatment with 1 was significantly increased compared with control cells (p < 0.05).

One new cycloartane triterpene glycoside from Beesia calthaefolia

One new cycloartane triterpene glycoside (1) was isolated from the whole plant of Beesia calthaefolia. Its structure was elucidated on the basis of extensive spectroscopic data analysis. Its inhibitory effect was measured by the classical pathway of the complement system, and compared with those of known related cycloartane glycosides 2 and 3, previously isolated by us from the same plant. Compounds 1 and 2 exhibited inhibitory activity of complement system with IC50 of 395.3 and 214 μM, respectively. The results suggested that OH at C-12, C-18 and C-15 along with the polarity could affect the inhibitory activity.

Effect of linezolid on hematological and oxidative parameters in rats.

Effect of linezolid is associated with hematocytopenia. A possible relationship between oxidative stress and hematologic toxicity has also been discussed. This present study was performed to determine the effect of oral administration of linezolid on hematological and oxidative parameters in rats. Rats were divided into five groups of 20 each. Drugs were given for a 15-day period. Control rats were vehicle treated. In the second and third groups, linezolid (50 and 125 mg kg−1) was given to rats twice a day (100 and 250 mg kg−1 per day) orally by gavage. The fourth group was given diet supplement that contained 250 mg kg−1 Vitamin E. The fifth group was given 125 mg kg−1 linezolid twice a day along with Vitamin E supplement. Blood cell counts (red blood cell (RBC), white blood cell (WBC) and platelet) were measured every 5 days. Enzymatic antioxidant activities, lipid peroxidation and free radical production were performed at the end of 15th day. The results showed that linezolid induces a decrease of WBC, RBC and platelet numbers in rat blood and enzymatic activities of superoxide dismutase and catalase in rat serum in a dose-dependent manner. While the content of malondialdehyde and nitric oxide was significantly increased in rats serum compared with the control group, Vitamin E supplement could partially reverse the above changes without affecting the control group. The results suggest that linezolid has effect on decreasing hemocyte level in rats, and oxidative stress may be one of the major causative factors. Antioxidant may prove to be a useful therapeutic option in the reversal of hematologic effects induced by linezolid.

AG4, a compound isolated from Radix Ardisiae Gigantifoliae, induces apoptosis in human nasopharyngeal cancer CNE cells through intrinsic and extrinsic apoptosis pathways.

3β-O-{α-L-Pyran rhamnose-(1→3)-[β-D-xylopyranose-(1→2)]-β-D-glucopyranose-(1→4)-[β-D-lucopyranose-(1→2)]-α-L-pyran arabinose}-cyclamiretin A (AG4) is a saponin component obtained from the Giantleaf Ardisia Rhizome (Rhizoma Ardisiae Gigantifoliae). The present study aimed to investigate the antitumor potential of AG4 and its possible mechanisms in human nasopharyngeal carcinoma cells (CNE). We exposed tumor cells to AG4 to investigate which cell line was the most sensitive to AG4. Cell viability was assessed using the MTT reduction assay, and the effects of AG4 on apoptosis, reactive oxygen species (ROS) content, mitochondrial membrane potential (MMP), and cell cycle were detected using a flow cytometer; the glutathione, superoxide dismutase and malondialdehyde activities were measured using colorimetric methods. The relative expressions of Bax, Bad, Bid, Bcl-2, and Fas mRNA were calculated using the (Equation is included in full-text article.)comparative method by real-time PCR studies and protein was detected by western blotting. AG4 markedly inhibited the growth of CNE cells by decreasing cell proliferation, inducing apoptosis, and blocking the cell cycle in the S phase. The release of caspase-3, caspase-8, and caspase-9 was stimulated by AG4 in CNE, and the decreased proliferation induced by AG4 was blocked by the inhibitor of pan caspase (Z-VAD-FMK). Moreover, the MMP was decreased in AG4-treated cells, and AG4-induced cell apoptosis was accompanied by a rapid and lasting increase in ROS, which was abolished by N-acetyl-L-cysteine (NAC); glutathione, superoxide dismutase, and malondialdehyde were regulated by AG4. AG4 inhibited Bcl-2 mRNA and protein expression and stimulated Bax, Bad, Bid, Fas mRNA, and protein expression in CNE cultures, suggesting an effect at the transcriptional and protein level. In addition, both the FasL inhibitor (AF-016) and the Bcl-2 family inhibitor (GX15-070) could prevent the cell apoptosis induced by AG4. The findings suggested that AG4-induced apoptosis in CNE cells involved a death receptor pathway and a Bcl-2 family-mediated mitochondrial signaling pathway by decreasing the MMPs in an ROS-dependent manner and regulating genes and proteins relative to apoptosis; also, regulation of cell cycles may also play a role in the antitumor mechanism of AG4.

New cycloartane triterpene glycosides from Beesia calthaefolia

Two new cycloartane triterpene glycosides (compounds 1 and 4) were isolated from the whole plants of Beesia calthaefolia with two known glycosides (compounds 2 and 3). Compounds 1 and 4 were assigned as (20S*,24R*)-16β-acetoxy-20, 24-epoxy-9, 19-cyclolanostane-3β,12β,15α,18,25-pentaol-3-O-β-d-xylopyranoside and (20S*,24 R*)-16β-acetoxy-20,24-epoxy-9,19-cyclolanostane-3β,15α,18,25-tetraol-3-O-β-d-xylopyranoside, respectively. Their structures were elucidated on the basis of extensive spectroscopic data analyses and comparison with spectroscopic data reported. Compounds 1 and 4 showed potential inhibition activity for the proliferation of splenocytes.

Synergistic Neuroprotective Effects of Two Herbal Ingredients via CREB-Dependent Pathway.

As two natural oligosaccharide esters, 3,6’-Disinapoyl sucrose (DISS) and tenuifolisideA (TFSA) are originating from the root of Polygala tenuifolia Willd, a traditional Chinese medicine used in treatment of mental disorders. Previous reports have shown that both of them possess in vitro neuroprotective effects by stimulating different upstream pathways related with cyclic AMP-responsive element-binding protein (CREB). In the present study, we investigated the additive neuroprotective effects of DISS and TFSA on Glu-induced damage of SY5Y cells and purposed the possible underlying mechanism. The interaction between DISS and TFSA showed a clear-cut synergistic effect as evidenced by combination index (CI). Additional evidence from biochemical (NOS activity) assays confirmed their additive inhibition on the Glu-induced NOS hyperactivation. Moreover, we showed that co-treatment of DISS and TFSA resulted in an additively up-regulated phosphorylation of CREB as well as increased expressions of CRTC1 and BDNF. Neuroprotective effects of DISS and TFSA on Glu-induced decrease in cell viability were blocked by MAPK/ERK1/2 inhibitor (U0126) and PI3-K inhibitor (LY290042). Nevertheless, the CRTC1 or BDNF expression induced by these two compounds was significantly reduced in the presence of either ERK or PI3-K inhibitor, indicating that the two oligosaccharide esters shared some common pathways in the regulation of CREB-BDNF pathway. Taken together, we, for the first time, showed that DISS and TFSA exerted the additive neuroprotective effects on CREB-BDNF signaling pathway through complementary mechanisms.

Enhanced Antitumor Activity of Cetuximab in Combination with the Jak Inhibitor CYT387 against Non-Small-Cell Lung Cancer with Various Genotypes

Cetuximab, an epidermal growth factor receptor (EGFR) inhibitor, is effective in the treatment of non-small-cell lung cancers (NSCLCs). However, resistance to EGFR inhibitors limits its effectiveness. In this study, we investigated the effectiveness of Jak-2 inhibitor, CYT387, in combination with cetuximab. Xenograft animal models were administered with cetuximab or CYT387 or their combination. It was observed that NSCLC cells exhibited enormous differences in responses to cetuximab; cell lines were more intrinsically resistant to cetuximab. In resistant cell lines (H1975 and H1650), the efficacy of cetuximab was increased when combined with CYT387, whereas CYT387 alone in low doses exhibited little effect on NSCLC cell proliferation. In addition, the antitumor activity of cetuximab was increased in H1975 resistant model in spite of low efficacy of cetuximab treatment alone in. Jak/STAT signaling was suppressed effectively by the combination of cetuximab and CYT387. In summary, our findings indicated that CYT387 has a potent indirect antitumor activity, and it is also synergistic in its activity in combination with cetuximab against NSCLC tumors, especially with cetuximab intrinsic-resistance tumors. These indications were mediated via Janus kinase (Jak)-signal transducer and transcription (STAT) pathway activator. Our results strongly and consistently supported the potential synergism of CYT387 as Jak inhibitor for anti-NSCLC therapy with EGFR-targeting agents.