Showing papers by "Jiangang Shen published in 2013"

Dietary Compound Isoliquiritigenin Inhibits Breast Cancer Neoangiogenesis via VEGF/VEGFR-2 Signaling Pathway

Abstract: Angiogenesis is crucial for cancer initiation, development and metastasis. Identifying natural botanicals targeting angiogenesis has been paid much attention for drug discovery in recent years, with the advantage of increased safety. Isoliquiritigenin (ISL) is a dietary chalcone-type flavonoid with various anti-cancer activities. However, little is known about the anti-angiogenic activity of isoliquiritigenin and its underlying mechanisms. Herein, we found that ISL significantly inhibited the VEGF-induced proliferation of human umbilical vein endothelial cells (HUVECs) at non-toxic concentration. A series of angiogenesis processes including tube formation, invasion and migration abilities of HUVECs were also interrupted by ISL in vitro. Furthermore, ISL suppressed sprout formation from VEGF-treated aortic rings in an ex-vivo model. Molecular mechanisms study demonstrated that ISL could significantly inhibit VEGF expression in breast cancer cells via promoting HIF-1α (Hypoxia inducible factor-1α) proteasome degradation and directly interacted with VEGFR-2 to block its kinase activity. In vivo studies further showed that ISL administration could inhibit breast cancer growth and neoangiogenesis accompanying with suppressed VEGF/VEGFR-2 signaling, elevated apoptosis ratio and little toxicity effects. Molecular docking simulation indicated that ISL could stably form hydrogen bonds and aromatic interactions within the ATP-binding region of VEGFR-2. Taken together, our study shed light on the potential application of ISL as a novel natural inhibitor for cancer angiogenesis via the VEGF/VEGFR-2 pathway. Future studies of ISL for chemoprevention or chemosensitization against breast cancer are thus warranted.

Targeting reactive nitrogen species: a promising therapeutic strategy for cerebral ischemia-reperfusion injury.

Abstract: Ischemic stroke accounts for nearly 80% of stroke cases. Recanalization with thrombolysis is a currently crucial therapeutic strategy for re-building blood supply, but the thrombolytic therapy often companies with cerebral ischemia-reperfusion injury, which are mediated by free radicals. As an important component of free radicals, reactive nitrogen species (RNS), including nitric oxide (NO) and peroxynitrite (ONOO−), play important roles in the process of cerebral ischemia-reperfusion injury. Ischemia-reperfusion results in the production of nitric oxide (NO) and peroxynitrite (ONOO−) in ischemic brain, which trigger numerous molecular cascades and lead to disruption of the blood brain barrier and exacerbate brain damage. There are few therapeutic strategies available for saving ischemic brains and preventing the subsequent brain damage. Recent evidence suggests that RNS could be a therapeutic target for the treatment of cerebral ischemia-reperfusion injury. Herein, we reviewed the recent progress regarding the roles of RNS in the process of cerebral ischemic-reperfusion injury and discussed the potentials of drug development that target NO and ONOO− to treat ischemic stroke. We conclude that modulation for RNS level could be an important therapeutic strategy for preventing cerebral ischemia-reperfusion injury.

Bioactivity-guided identification and cell signaling technology to delineate the lactate dehydrogenase A inhibition effects of Spatholobus suberectus on breast cancer.

Abstract: Aerobic glycolysis is an important feature of cancer cells. In recent years, lactate dehydrogenase A (LDH-A) is emerging as a novel therapeutic target for cancer treatment. Seeking LDH-A inhibitors from natural resources has been paid much attention for drug discovery. Spatholobus suberectus (SS) is a common herbal medicine used in China for treating blood-stasis related diseases such as cancer. This study aims to explore the potential medicinal application of SS for LDH-A inhibition on breast cancer and to determine its bioactive compounds. We found that SS manifested apoptosis-inducing, cell cycle arresting and anti-LDH-A activities in both estrogen-dependent human MCF-7 cells and estrogen-independent MDA-MB-231 cell. Oral herbal extracts (1 g/kg/d) administration attenuated tumor growth and LDH-A expression in both breast cancer xenografts. Bioactivity-guided fractionation finally identified epigallocatechin as a key compound in SS inhibiting LDH-A activity. Further studies revealed that LDH-A plays a critical role in mediating the apoptosis-induction effects of epigallocatechin. The inhibited LDH-A activities by epigallocatechin is attributed to disassociation of Hsp90 from HIF-1α and subsequent accelerated HIF-1α proteasome degradation. In vivo study also demonstrated that epigallocatechin could significantly inhibit breast cancer growth, HIF-1α/LDH-A expression and trigger apoptosis without bringing toxic effects. The preclinical study thus suggests that the potential medicinal application of SS for inhibiting cancer LDH-A activity and the possibility to consider epigallocatechin as a lead compound to develop LDH-A inhibitors. Future studies of SS for chemoprevention or chemosensitization against breast cancer are thus warranted.

Pros and Cons of Current Approaches for Detecting Peroxynitrite and Their Applications

Abstract: Peroxynitrite, a representative of reactive nitrogen species, plays important roles in the physiological and pathological processes of many oxidative stress-related diseases It is generated from the reaction of nitric oxide (NO) and superoxide (O2·-) and is far more active than its precursors Peroxynitrite can be further decomposed into other cytotoxic reactive species Peroxynitrite and its derivatives can interact with various biomolecules such as DNA and proteins Due to its high reactivity and short lifetime, accurate detection of peroxynitrite in biological systems is a challenge task In the last decade, huge efforts have been made to develop reliable techniques to assess the generation of peroxynitrite in various cellular and animal experiments There are three major approaches for peroxynitrite detection, including electrochemical sensors, detection of nitrotyrosine formation, and fluorescent probes Particularly, progress has been made in developing novel fluorescent probes to detect peroxynitrite with relatively high sensitivity and specificity Herein, we review the recent progress made in peroxynitrite detection methods and discuss the advantages and disadvantages of these methods The development of these techniques will offer new opportunities for understanding the roles of peroxynitrite in the oxidative stress-related physiological and pathological conditions and provide platforms for drug discovery targeting peroxynitrite and other free radicals for therapeutic purposes

Targeted over-expression of endothelin-1 in astrocytes leads to more severe brain damage and vasospasm after subarachnoid hemorrhage

Abstract: Background: Endothelin-1 (ET-1) is a potent vasoconstrictor, and astrocytic ET-1 is reported to play a role in the pathogenesis of cerebral ischemic injury and cytotoxic edema. However, it is still unknown whether astrocytic ET-1 also contributes to vasogenic edema and vasospasm during subarachnoid hemorrhage (SAH). In the present study, transgenic mice with astrocytic endothelin-1 over-expression (GET-1 mice) were used to investigate the pathophysiological role of ET-1 in SAH pathogenesis. Results: The GET-1 mice experienced a higher mortality rate and significantly more severe neurological deficits, blood–brain barrier breakdown and vasogenic edema compared to the non-transgenic (Ntg) mice following SAH. Oral administration of vasopressin V1a receptor antagonist, SR 49059, significantly reduced the cerebral water content in the GET-1 mice. Furthermore, the GET-1 mice showed significantly more pronounced middle cerebral arterial (MCA) constriction after SAH. Immunocytochemical analysis showed that the calcium-activated potassium channels and the phospho-eNOS were significantly downregulated, whereas PKC-α expression was significantly upregulated in the MCA of the GET-1 mice when compared to Ntg mice after SAH. Administration of ABT-627 (ETA receptor antagonist) significantly down-regulated PKC-α expression in the MCA of the GET-1 mice following SAH. Conclusions: The present study suggests that astrocytic ET-1 involves in SAH-induced cerebral injury, edema and vasospasm, through ETA receptor and PKC-mediated potassium channel dysfunction. Administration of ABT-627 (ETA receptor antagonist) and SR 49059 (vasopressin V1a receptor antagonist) resulted in amelioration of edema and vasospasm in mice following SAH. These data provide a strong rationale to investigate SR 49059 and ABT-627 as therapeutic drugs for the treatment of SAH patients.

Diarylamine-based fluorogenic probes for detection of peroxynitrite

Abstract: Provided herein are improved fluorogenic compounds and probes that can be used as reagents for measuring, detecting and/or screening peroxynitrite. The fluorogenic compounds of the invention can produce fluorescence colors, such as green, yellow, red, or far-red. Also provided herein are fluorogenic compounds for selectively staining peroxynitrite in the mitochondria of living cells. Provided also herein are methods that can be used to measure, directly or indirectly, the presence and/or amount of peroxynitrite in chemical samples and biological samples such as cells and tissues in living organisms. Also provided are high-throughput screening methods for detecting or screening peroxynitrite or compounds that can increase or decrease the level of peroxynitrite in chemical and biological samples.

A predictive model of Vibrio cholerae for combined temperature and organic nutrient in aquatic environments.

Abstract: Aims To develop a predictive model for Vibrio cholerae in sea water. Methods and Results The growth curves of V. cholerae NE-9 at different temperatures (range from 10 to 30 degrees C) and chemical oxygen demand (COD) concentration (range from 5 to 40 mg l-1) were determined. The modified logistic model and Baranyi model were chosen to regress the growth curves. A new method for modelling effects of temperature and COD on the specific growth rate (mu) was successfully developed by a combination of modified square roottype equation and saturation growth rate model. The coefficient of determination (R2), bias factor (Bf) and accuracy factor (Af) were taken to assess the performance of the established model. Logistic model produced a good fit to the observed data (R2 = 0.952). However, the Baranyi model provided biologically plausible parameter estimates. The overall predictions for V. cholerae NE-9 growth agreed well with observed plate counts, and the average R2, Bf and Af values were 0.967, 1.198 and 1.201, respectively. Conclusion The predicted model agreed well with observed data, and the result can be applied for the prediction of V. cholerae in actual environments. Significance and Impact of the Study The results of this study provide the basis for the prediction of V. cholerae in sea water.

The XRCC1 Arg399Gln genetic polymorphism contributes to hepatocellular carcinoma susceptibility: an updated meta-analysis.

Abstract: The potential correlation of X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln polymorphism with hepatocellular carcinoma (HCC) susceptibility is ambiguous. Taking account of inconsistent results of previous meta-analyses and new emerging literatures, we conducted a meta-analysis covering 15 case-control datasets to evaluate the relationship. Relevant studies from Medline, Embase and CNKI were retrieved. A fixedeffect model or a random-effect model, depending on between-study heterogeneity, were applied to estimate the association between XRCC1 polymorphism Arg399Gln and HCC risk with the results presented as odds ratios (ORs) and 95% confidence intervals (95% CIs). In accordance with Hardy-Weinberg equilibrium, 15 studies with data for 6,556 individuals were enrolled in this systematic review. For overall HCC,thr XRCC1 polymorphism Arg399Gln was significantly associated with HCC susceptibility in a homozygote model as well as in a dominant model (G/G vs. A/A, OR=1.253, p=0.028; G/G+A/G vs. A/A, OR= 1.281, p=0.047, respectively), but not in a heterozygote model (A/G vs. A/A, OR=1.271, p=0.066) or a recessive model (G/G vs. A/G + A/A, OR= 1.049, p=0.542). Similar results were also observed on stratification analysis by ethnicity (A/G vs. A/A, OR=1.357, p=0.025; G/G vs. A/A, OR=1.310, p=0.011; G/G+A/G vs. A/A, OR= 1.371, p=0.013). However, no potential contribution of XRCC1 Arg399Gln polymorphism to HCC susceptibility in HBV/HCV subgroups was identified. No publication bias was found in this study. In conclusion, the XRCC1 Arg399Gln polymorphism contributes to HCC susceptibility. Due to the lack of studies in Western countries, further large-sample and rigorous studies are needed to validate the findings.