Hai-Ning Zhen

New enlightenment of French Paradox: resveratrol's potential for cancer chemoprevention and anti-cancer therapy.

Epidemiological studies have revealed an inverse correlation between red wine consumptions and the incidence of cardiovascular disease, a phenomenon commonly known as the “French Paradox”; namely, the fact that the incidence of heart infarction in France is about 40% lower than in the rest of Europe, despite a diet being traditionally rich in saturated fat.

Neuroprotective effect of osthole against acute ischemic stroke on middle cerebral ischemia occlusion in rats

Osthole, a natural coumarin derivative, has taken considerable attention because of its diverse pharmacological functions. It has been reported to be useful in the treatment of chronic cerebral hypoperfusion and neuronal damage. In the present study, we examined the neuroprotective effect of osthole and its potential mechanisms against acute ischemic stroke induced by middle cerebral artery occlusion (MCAO) in rats. The rats were pretreated with osthole 10, 20 and 40 mg/kg 30 min before MCAO. The neuroprotective effect of osthole against acute ischemic stroke was evaluated by neurological deficit score (NDS), dry-wet weight and 2,3,5-triphenyltetrazolium chloride (TTC) staining. The contents of malondialdehyde (MDA) and glutathione (GSH), activity of myeloperoxidase (MPO) and the level of interleukin (IL)-1β and IL-8 after 2h of MCAO in rats were detected to investigate its anti-oxidative action and anti-inflammatory property. Pretreatment with osthole significantly increased in GSH, and decreased the volume of infarction, NDS, edema, MDA, MPO, IL-1β and IL-8 compared with rats in the MCAO group at 24h after MCAO. The study suggests the neuroprotective effect of osthole in the MCAO model of rats. The anti-oxidative action and anti-inflammatory property of osthole may contribute to a beneficial effect against stroke.

Correlation of l-methyl-11C-methionine (MET) uptake with l-type amino acid transporter 1 in human gliomas

Abstractl-Type amino acid transporter 1 (LAT1) is a neutral amino acid transport system and is a major route for the transport of large neutral amino acids, including methionine, through the plasma membrane. LAT1 requires the heavy chain of 4F2 cell surface antigen (4F2hc) for its functional expression. Positron emission tomography (PET) with l-[methyl-11C] methionine (MET) provides information about amino acid metabolism in brain tumors. We conducted a clinicopathologic study to elucidate the correlation of LAT1 and 4F2hc expression with MET uptake in patients with newly diagnosed human gliomas. Thirty-three newly diagnosed glioma patients were enrolled in this study. Uptake of MET in the tumor was evaluated with the maximum standardized uptake value (SUVmax). Expression of the LAT1, 4F2hc, and CD34, and Ki-67 labeling index of the tumor were analyzed by immunohistochemical staining, and the correlation with the SUVmax in the tumors was examined. Expression of LAT1 and 4F2hc was higher in high-grade gliomas than in low-grade gliomas. The grade of LAT1 immunostaining increased with glioma grade. LAT1 was mainly expressed in the tumor cytoplasm and vascular endothelium and 4F2hc was mainly expressed in the tumor cytoplasm and plasma membrane. Expression of LAT1 but not 4F2hc was significantly correlated with MET SUVmax. Expression of LAT1 in the tumor vascular endothelium is significantly correlated with CD34 positive microvessel density. In conclusion, MET SUVmax correlates with LAT1 expression in the tumor in newly diagnosed gliomas. MET transport may be increased by an increased number of microvessels combined with a higher density or activity of LAT1 in the tumor endothelial cells in high-grade gliomas. Use of MET-PET as a molecular target combined with anti-angiogenesis in glioma therapy should be addressed in future studies.

Resveratrol attenuates ischemic brain damage in the delayed phase after stroke and induces messenger RNA and protein express for angiogenic factors.

BACKGROUND It has been reported recently that resveratrol preconditioning can protect the brain from ischemia-reperfusion injury. However, it was unclear whether resveratrol administration after stroke was beneficial to the delayed phases after focal cerebral ischemia injury. This study investigated the effects and possible protective mechanism of resveratrol on the delayed phase after focal cerebral ischemia injury in mice. METHODS Mice were randomly assigned to five groups according to the time of administration of resveratrol. Control group mice received a corresponding volume of saline solution (0.9% NaCl) containing 20% hydroxypropyl h-cyclodextrin by gavage and were exposed to middle cerebral artery (MCA) occlusion and reperfusion injury. The treatment groups received resveratrol (50 mg/kg/d, gavage) until day 7. Ischemia group mice received their first dose 5 minutes before MCA ischemia, reperfusion group mice received their first dose 5 minutes before MCA reperfusion, first-day, group mice received their first dose 24 hours after MCA reperfusion, and third-day group mice received their first dose at 72 hours after MCA reperfusion. Brain injury was evaluated by triphenyltetrazolium chloride staining and neurologic examination 7 days after reperfusion. The microvascular cell number was examined with immunohistochemistry staining. Effect of resveratrol on matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) gene expression was investigated with reverse transcriptase-polymerase chain reaction and Western blot. RESULTS The mean neurologic scores and infarct volumes of the ischemia and reperfusion groups were lower than that of the control group at 7 days after MCA reperfusion (P < .05). Immunohistochemistry staining showed significantly less reduction in the number of microvessels in the cortical area of mice of the ischemia and reperfusion groups compared with controls. The ischemic hemispheres of the ischemia and reperfusion groups showed significantly (P < .05) elevated levels of protein of MMP-2 and VEGF. CONCLUSIONS Resveratrol administration by gavage provided an important neuroprotective effect on focal cerebral ischemic injury in the delayed phase. The elevated MMP-2 and VEGF levels might be important in the neuroprotective effect of resveratrol administration by inducing angiogenesis.

Isoform-specific expression of 14-3-3 proteins in human astrocytoma.

BACKGROUND 14-3-3 protein plays crucial roles in tumorigenesis, including the maintenance of cell cycle and DNA repair, the prevention of apoptosis, among others. In mammalian cells, seven 14-3-3 isoforms (beta, epsilon, zeta, eta, theta, gamma and sigma) have been identified and each of these seems to have distinct tissue localizations and isoform-specific functions. In the present study, the levels of all seven 14-3-3 isoforms were examined in astrocytoma. METHODS The expression of 14-3-3 isoforms and their protein expression levels were examined in five glioma cell lines by western blotting. Then in astrocytoma tissues, we investigated expression percentages of each isoform by immunohistochemistry. The protein and mRNA expression levels of each isoform were also detected by western blotting and RT-PCR, respectively. RESULTS 14-3-3beta and eta were specifically expressed in astrocytoma, and their expression frequencies and levels increased with the increase of astrocytoma malignancy. The result from glioma cell lines was consistent with that from astrocytoma tissue. CONCLUSIONS In our study, we found two tumor-specific isoforms of 14-3-3 in astrocytoma. They might be involved in astrocytoma tumorigenesis and may be useful as targets for therapy.

Neuroprotective effects of osthole pretreatment against traumatic brain injury in rats.

Osthole, a coumarin compound isolated from the plant-derived herb Cnidium monnieri, has been the subject of considerable interest because of its broad spectrum of pharmacological properties. The aim of this study was to investigate the potential protective effects of osthole in adult rats in the setting of traumatic brain injury (TBI). We employed Feeneys weight-drop model to ascertain whether intraperitoneal administration of osthole (10mg/kg, 20mg/kg and 40 mg/kg) 30 min before TBI could reduce the severity of neurological deficits, cerebral edema, and hippocampal neuron loss. The levels of malondialdehyde (MDA) and glutathione (GSH), the activity of superoxide dismutase (SOD), the expressions of Bcl-2, Bax, and active caspase-3, and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive apoptotic cells were also measured to characterize the antioxidative and antiapoptotic properties. A significant reduction of neurological deficits, cerebral edema and hippocampal neuron loss was observed in the osthole pretreatment groups (20mg/kg and 40 mg/kg, but not 10mg/kg) by 24h after TBI compared with the TBI group. Furthermore, pretreatment with osthole (40 mg/kg) significantly increased the activity of SOD, the level of GSH, and the ratio of Bcl-2/Bax, and also reduced the level of MDA, the expression of active caspase-3, and the number of apoptotic cells at 24h after TBI. In summary, these results suggested that osthole had a neuroprotective effect against TBI, and the protection may be associated with its antioxidative and antiapoptotic functions.

The brain-derived neurotrophic factor is associated with alcohol dependence-related depression and antidepressant response

Brain-derived neurotrophic factor (BDNF) plays an essential role in neuronal survival, proliferation, and synaptic remodeling and modulates the function of many other neurotransmitters. Additionally, it likely underlies neurodegenerative and psychiatric disorders, including alcohol dependence-related depression (AD-D). Here, we investigated the possible association between three single nucleotide polymorphisms (SNPs) of the BDNF gene (rs13306221, rs6265, rs16917204) and AD-D. Of 548 patients with alcohol dependence (AD), 166 had AD-D and 312 healthy controls. Response to 8-week sertraline treatment was also assessed. The frequency of the A allele of rs6265 (Val66Met) was significantly higher in AD-D patients than in the healthy controls (p=0.009 after Bonferroni correction). The analysis revealed a strong association between the rs6265 genotype distribution and AD-D (p=0.005 after Bonferroni correction), and the A allele of rs6265 was significantly overrepresented in AD-D patients compared to AD without depression (AD-nD) patients (p=0.001 after Bonferroni correction). Additionally, carriers of the A allele of rs6265 responded better to sertraline treatment (p=0.001). Our results suggested a novel association between BDNF rs6265 and AD-D. These findings might lead to earlier detection of AD-D, perhaps providing better tools for clinical care of these patients in the future.

Resveratrol inhibits cell growth and induces apoptosis of rat C6 glioma cells.

Resveratrol (Res) has been reported to inhibit tumor initiation, promotion, and progression in a variety of cell culture systems depending on the specific cell type and cellular environment. In the present study, we determined the effect of Res on the cell growth and apoptosis of rat glioma C6 cell line as well as mouse fibroblast 3T3 cell line, in vitro. Concurrently, we investigated whether caspase-3 is involved in the Res-induced apoptosis of rat glioma cells. Exposure to Res exhibits a significant anti-proliferative effect and induces an increase in the population of apoptotic cells on C6 cells in a concentration- and time-dependent manner, but not for normal 3T3 fibroblast cells, as measured by methyl thiazolyl tetrazolium assay and flow cytometer. Distinguished increase of C6 cells in S phase is observed after the treatment of Res as compared to insignificant change in cell cycle distribution of 3T3 cells. TdT-mediated dUTP nick end labeling fluorescence staining, HE staining, and scanning electron microscope revealed abnormal morphology and ultrastructure in C6 cells treated with Res. Our data showed that Res can increase the expression and induced the activation of caspase-3 in rat glioma C6 cells. These results suggest that Res has significant apoptosis-inducing effect on C6 glioma cells other than normal fibroblast 3T3 cells in vitro and caspase-3 may act as a potential mediator in the process.

Up-regulation of EphA2 and down-regulation of EphrinA1 are associated with the aggressive phenotype and poor prognosis of malignant glioma

Malignant gliomas display over-expression of the receptor tyrosine kinase EphA2. However, expression levels of the EphA2 ligand, EphrinA1, have not been fully elucidated. Seventy-eight patients with primary gliomas were included in this study who underwent surgical resection, radiation, and chemotherapy. The expression of EphA2 and EphrinA1 in tumors was assessed by immunohistochemistry and was statistically analyzed in combination with the follow-up data of patients. EphA2 was highly expressed in most malignant gliomas, but EphrinA1 was expressed at low levels in these tumors. The increased EphA2 expression is associated with higher-grade histology and poor patient prognosis. Contrary to this, the increased EphrinA1 expression is associated with lower-grade histology, but not associated with poor patient prognosis. Moreover, patients with tumors positive for EphA2 and negative for EphrinA1 had significantly shorter overall and progression-free survival than patients with tumors positive for both EphA2 and EphrinA1, negative for both EphA2 and EphrinA1, or negative for EphA2 and positive for EphrinA1. RNAi-mediated suppression of endogenous EphA2 in human glioblastoma multiforme cells resulted in increased EphrinA1 levels, as well as decreased cell viability, anchorage independence and in vitro invasion, and increased apoptosis. Furthermore, suppression of EphA2 resulted in delayed tumor growth in mice xenografts. Together, these data indicate that up-regulation of EphA2 and down-regulation of Ephrina1 may correlate with poor prognosis for patients with high-grade glioma. EphA2 suppression partially reversed the aggressive phenotypes of malignant gliomas, possibly through up-regulating EphrinA1 expression, which may help explain how EphA2 modulates the malignant progression of gliomas.

Expression of EphA2 in Human Astrocytic Tumors: Correlation with Pathologic Grade, Proliferation and Apoptosis

A high expression of EphA2 has been detected in many non-central nervous system tumors; however, the EphA2 expression in brain astrocytic tumors remains unclear. In this study, we investigated the expression of EphA2 mRNA and protein in 90 cases of human astrocytic tumors by reverse transcription polymerase chain reaction and immunohistochemistry, respectively. The proliferative index (PI) of tumor cells was evaluated by Ki-67 immunohistochemistry, and the apoptotic index (AI) was determined by TdT-mediated dUTP nick end labeling assay. The correlation between EphA2 expression, pathologic grade, proliferation and apoptosis of astrocytic tumors was further analyzed. The results showed that 47.8% of cases expressed EphA2 mRNA and 43.3% of cases expressed EphA2 protein. With increasing pathologic grade, the positive rate of EphA2 mRNA and protein, as well as the EphA2 immunoreactivity score (IRS), increased markedly. The PI in the EphA2-positive group was significantly higher than in the EphA2-negative group. In addition, the PI was positively correlated with EphA2 IRS. Although there was no significant difference between the AI in the EphA2-positive group and that in the EphA2-negative group, the AI was inversely correlated with EphA2 IRS. Therefore, EphA2 may be a new biomarker for astrocytic tumors. It may also affect the proliferation and apoptosis of tumor cells and be an attractive therapy target for astrocytic tumors.