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author:("Chen, yongei")
1.  Evaluation of ERG Responsive Proteome in Prostate Cancer 
The Prostate  2013;74(1):70-89.
Gene fusion between TMPRSS2 promoter and the ERG proto-oncogene is a major genomic alteration found in over half of prostate cancers (CaP), which leads to aberrant androgen dependent ERG expression. Despite extensive analysis for the biological functions of ERG in CaP, there is no systematic evaluation of the ERG responsive proteome (ERP). ERP has the potential to define new biomarkers and therapeutic targets for prostate tumors stratified by ERG expression.
Global proteome analysis was performed by using ERG (+) and ERG (−) CaP cells isolated by ERG immunohistochemistry defined laser capture microdissection and by using TMPRSS2-ERG positive VCaP cells treated with ERG and control siRNA.
We identified 1196 and 2190 unique proteins stratified by ERG status from prostate tumors and VCaP cells, respectively. Comparative analysis of these two proteomes identified 330 concordantly regulated proteins characterizing enrichment of pathways modulating cytoskeletal and actin reorganization, cell migration, protein biosynthesis, and proteasome and ER-associated protein degradation. ERPs unique for ERG (+) tumors reveal enrichment for cell growth and survival pathways while proteasome and redox function pathways were enriched in ERPs unique for ERG (−) tumors. Meta-analysis of ERPs against CaP gene expression data revealed that Myosin VI and Monoamine oxidase A were positively and negatively correlated to ERG expression, respectively.
This study delineates the global proteome for prostate tumors stratified by ERG expression status. The ERP data confirm the functions of ERG in inhibiting cell differentiation and activating cell growth, and identify potentially novel biomarkers and therapeutic targets.
PMCID: PMC4075339  PMID: 24115221
2.  Predominance of ERG-negative high-grade prostate cancers in African American men 
Molecular and Clinical Oncology  2014;2(6):982-986.
Erythroblast transformation-specific-related gene (ERG) fusions, the most common and validated prostate cancer (CaP) genome alteration, result in alterations in the expression of the ERG oncoprotein. Significantly lower frequencies of ERG have been reported in tumors of African American (AA) in comparison to Caucasian American (CA) men. Building on our preliminary observations, this study has focused on the increased association of the ERG-negative status with higher-grade prostate tumors in AA men. Representative whole-mount prostate sections from a matched cohort of 63 AA and 63 CA men with Gleason scores of 4+3 and those with Gleason scores of 8–10 were analyzed for ERG oncoprotein by immunohistochemistry. The striking finding of this study was that ERG expression was 3 times more likely to be present in the higher-grade index tumors of CA men compared to AA men (31 of 63 vs. 10 of 63 patients, respectively; P<0.0001). Although the mechanisms underlying these differences have not been elucidated, the present study along with our previous observations underscores that ERG typing may enhance the understanding of ethnic differences and future targeted therapy of CaP.
PMCID: PMC4179793  PMID: 25279185
prostate cancer; erythroblast transformation-specific-related gene; transmembrane protease serine 2 gene fusion; race; ethnicity
3.  Incremental Treatments with Laser Therapy Augments Good Behavioral Outcome in the Rabbit Small Clot Embolic Stroke Model 
Lasers in medical science  2012;28(4):1085-1089.
Transcranial near-infrared laser therapy (TLT) improves behavioral outcome in animal stroke models when applied as single treatment within the 24 h of the stroke onset. It is unknown if multiple TLT treatments have an added beneficial effect. We aim to determine whether multiple irradiations with TLT would have further improvement in behavioral outcomes in the rabbit small clot embolic stroke model (RSCEM).
Using the RSCEM, two and three TLT treatments (7.5–20 mW/cm2) were compared against single laser treatment alone (7.5–10.8 mW/cm2). Two sham irradiation groups were added for control curves. The double treatment group received TLT at 3hrs and 5hrs and the triple treatment group at 2hr, 3hrs and 4hrs after embolization. Behavioral analysis was conducted 24 hours after embolization using a dichotomized behavioral score. Determination of the effective clot amount (mg) that produces neurological deficits in 50% of the rabbits (P50) was used to compare TLT treatments with sham.
The P50 for double treatment was 5.47±0.90, n=39, the corresponding P50 value for a single treatment was 3.87±0.73, n=38, and the corresponding control curve was 3.25±0.4, n=32. The P50 for triple treatment was 5.91±0.49, n=23, the corresponding P50 value for a single treatment was 3.09±0.59, n=15, and the corresponding control curve was 1.71±0.26, n=17. Triple treatment had a 91% of improvement when compared with single treatment and 245% improvement when compared with sham.
The present study suggests that additional TLT treatments provide further behavioral improvement when given during the acute ischemic stroke phase.
PMCID: PMC3538923  PMID: 22945539
Acute ischemic stroke; Lower level laser therapy; Neuroprotection; Photobiology
4.  Functional antagonism of TMPRSS2-ERG splice variants in prostate cancer 
Genes & Cancer  2014;5(7-8):273-284.
The fusion between ERG coding sequences and the TMPRSS2 promoter is the most prevalent in prostate cancer (CaP). The presence of two main types of TMPRSS2-ERG fusion transcripts in CaP specimens, Type I and Type II, prompted us to hypothesize that the cumulative actions of different ERG variants may impact CaP development/progression. Using TMPRSS2-ERG3 (Type I) and TMPRSS2-ERG8 (Type II) expression vectors, we determined that the TMPRSS2- ERG8 encoded protein is deficient in transcriptional regulation compared to TMPRSS2-ERG3. Co-transfection of vectors resulted in decreased transcriptional regulation compared to TMPRSS2-ERG3 alone, suggesting transdominance of ERG8. Expression of exogenous ERG8 protein resulted in a decrease in endogenous ERG3 protein levels in TMPRSS2-ERG positive VCaP cells, with a concomitant decrease in C-MYC. Further, we showed a physical association between ERG3 and ERG8 in live cells by the bimolecular fluorescence complementation assay, providing a basis for the observed effects. Inhibitory effects of TMPRSS2-ERG8 on TMPRSS2- ERG3 were also corroborated by gene expression data from human prostate cancers, which showed a positive correlation between C-MYC expression and TMPRSS2-ERG3/TMPRSS2- ERG8 ratio. We propose that an elevated TMPRSS2-ERG3/TMPRSS2-ERG8 ratio results in elevated C-MYC in CaP, providing a strong rationale for the biomarker and therapeutic utility of ERG splice variants, along with C-MYC.
PMCID: PMC4162137  PMID: 25221645
ERG; Splice variants; Prostate cancer; Dominant negative; C-MYC
5.  Differences in the frequency of ERG oncoprotein expression between index tumors of Caucasian American and African American prostate cancer patients 
Urology  2012;80(4):749-753.
Tosystematically evaluate ERG alterations in the multifocal tumor context by using whole-mount prostatectomy specimens of African American and Caucasian American patients matched for age, pathologic grade and stage. Oncogenic activation of the ETS-Related Gene (ERG) is the most common early genomic alteration in prostate cancer patients in Western countries. However, ERG alterations have not been systematically examined in African American patients with known higher risk of prostate cancer incidence and mortality.
ERG oncoprotein expression was analyzed in 91 Caucasian American and 91 African American prostate cancer patients matched for age, Gleason score and pathologic stage. A unique aspect of this study was the evaluation of ERG in whole-mount prostatectomy sections, minimizing sampling bias and allowing the careful assessment of ERG in the multifocal tumor context of prostate cancer.
The frequency of ERG positive prostate tumors was significantly greater among Caucasian Americans vs. African Americans when assessed in all tumor foci (41.9% vs. 23.9%, p<0.0001). Markedly higher frequency of the ERG oncoprotein expression was noted between the index tumors of Caucasian Americans (63.3%) and African Americans (28.6%). Of note, in African American patients the higher grade index tumors were predominantly ERG negative.
ERG typing of prostate tumors establishes a major difference between the index tumors of Caucasian and African American patients. ERG negative index tumors may indicate less favorable outcome in African American patients. This study underscores that typing of prostate tumors for ERG may enhance our understanding of biological differences between the examined ethnic groups.
PMCID: PMC3462242  PMID: 22950997
6.  Perlecan Domain V is Upregulated in Human Brain Arteriovenous Malformation (BAVM) and could Mediate VEGF Effect in Lesional Tissue 
Neuroreport  2012;23(10):627-630.
Brain arteriovenous malformation (BAVM), a rare but important cause of intracranial hemorrhage, has increased angiogenesis and inflammation as key components of the nidus of abnormal vessels and stroma that form the resected surgical specimen. Accordingly, vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGFβ) have both been implicated in BAVM pathology for their pro-angiogenic and vascular-regulating roles. The c-terminal fragment of the extracellular matrix component perlecan (domain V, DV) has been shown to be increased and to, via the α5β1 integrin, increase VEGF levels in and around areas of cerebral ischemic injury, another pro-angiogenic condition. We sought to determine whether the concentrations of DV, DV’s proangiogenic receptor α5β1 integrin, or DV’s anti-angiogenic receptor α2β1 integrin are elevated in human BAVM tissue. DV levels were increased in BAVM compared to control brain tissue from epileptic resection, as was α5β1 integrin. Additionally, α5β1 integrin was preferentially increased and localized to endothelial cells compared to α2β1 integrin. VEGF and TGFβ levels were also increased in BAVM compared to control tissue. Furthermore, increases in all components were strongly correlated. Excessive generation of pro-angiogenic DV in BAVM suggests that DV may participate in its pathology and may represent a future therapeutic target.
PMCID: PMC3535489  PMID: 22643235
Arteriovenous Malformation; AVM
7.  Development of a Spontaneous Liver Disease Resembling Autoimmune Hepatitis in Mice Lacking Tyro3, Axl and Mer Receptor Tyrosine Kinases 
PLoS ONE  2013;8(6):e66604.
Autoimmune hepatitis (AIH) is a severe type of chronic liver disease. The lack of appropriate animal models has resulted in a limited understanding regarding the etiology of AIH. Here, we demonstrated that mice deficient in Tyro3, Axl and Mer (TAM) receptor tyrosine kinases (RTKs) developed persistent inflammatory liver damage resembling AIH. Tyro3−/−Axl−/−Mer−/− triple mutant (TAM−/−) mice exhibited chronic hepatitis, manifested by progressive appearance of interface hepatitis, immune cell infiltrations and elevated inflammatory cytokine levels in the liver. Accordingly, increased levels of transaminases were observed. Moreover, characteristic autoantibodies and high levels of plasma immunoglobulin G for AIH were detected as TAM−/− mice aged. Finally, we provided evidence that the liver damage in TAM−/− mice mainly result from bone marrow-derived cells and could be rescued by transplantation of WT bone marrow cells. Results suggest that TAM RTKs play an important role in maintaining immune tolerance of the liver.
PMCID: PMC3684578  PMID: 23799121
8.  Long-term overall survival and metastasis-free survival for men with prostate-specific antigen-recurrent prostate cancer after prostatectomy: analysis of the Center for Prostate Disease Research National Database 
Bju International  2010;108(3):378-385.
To describe metastasis-free survival (MFS) and overall survival (OS) among men with prostate-specific antigen (PSA)-recurrent prostate cancer after radical prostatectomy who did not receive additional therapy until metastasis, using a multicentre database capturing a wide ethnic mix.
A retrospective analysis of the Center for Prostate Disease Research National Database (comprised of five US military hospitals and one civilian centre) was performed for patients with PSA relapse (≥0.2 ng/mL) after radical prostatectomy who had no additional therapy until the time of radiographic metastatic disease.
We investigated factors influencing metastasis and all-cause mortality using univariate and multivariate Cox regression analysis.
There were a total of 346 men who underwent radical prostatectomy between May 1983 and November 2008 and fulfilled the entry criteria. All patients had information on survival and 190 men had information on metastasis. Among patients with survival data (n = 346), 10-year OS was 79% after a median follow-up of 8.6 years from biochemical recurrence.
Among men with metastasis data (n = 190), 10-year MFS was 46% after a median follow-up of 7.5 years.
In Cox regressions, four clinical factors (Gleason score, pathological stage, time to PSA relapse and PSA doubling time), as well as age, were predictive of OS and/or MFS in univariate analysis, although only PSA doubling time (≥9 vs 3–8.9 vs <3 months) remained independently predictive of these outcomes in multivariate analysis (P < 0.001).
This multicentre multi-ethnic dataset shows that OS and MFS can be extensive for men with PSA-recurrent prostate cancer, even in the absence of further therapy before metastasis.
This unique patient cohort, the second largest of its type after the Johns Hopkins cohort, confirms that PSA doubling time is the strongest determinant of OS and MFS in men with PSA-recurrent disease.
Longer follow-up and more events will be required to determine whether other variables may also contribute to these outcomes.
PMCID: PMC3402027  PMID: 21091976
metastasis-free survival; natural history; overall survival; prostate cancer; PSA recurrence
9.  Arteriovenous Malformation in the Adult Mouse Brain Resembling the Human Disease 
Annals of neurology  2011;69(6):954-962.
Brain arteriovenous malformations (bAVM) are an important cause of hemorrhagic stroke. The underlying mechanisms are not clear. No animal model for adult bAVM is available for mechanistic exploration. Patients with Hereditary Hemorrhagic Telangiectasia Type2 (HHT2) with activin receptor-like kinase 1 (ALK1; ACVRL1) mutations have a higher incidence of bAVM than the general population. We tested the hypothesis that VEGF stimulation with regional homozygous deletion of Alk1 induces severe dysplasia in the adult mouse brain, akin to human bAVM.
Alk12f/2f (exons 4–6 flanked by loxP sites) and wild-type (WT) mice (8–10 weeks old) were injected with Ad-Cre (2×107 PFU, adenoviral vector expressing Cre recombinase) and AAV-VEGF (2×109 genome copies, adeno-associated viral vectors expressing VEGF) into the basal ganglia. At 8 weeks, blood vessels were analyzed.
Gross vascular irregularities were seen in Alk1 2f/2f mouse brain injected with Ad-Cre and AAV-VEGF. The vessels were markedly enlarged with abnormal patterning resembling aspects of the human bAVM phenotype, displayed altered expression of the arterial and venous markers (EphB4 and Jagged-1), and showed evidence of arteriovenous shunting. Vascular irregularities were not seen in similarly treated WT mice.
Our data indicate that post-natal, adult formation of the human disease bAVM is possible, and that both genetic mutation and angiogenic stimulation are necessary for lesion development. Our work not only provides a testable adult mouse bAVM model for the first time, but also suggests that specific medical therapy can be developed to slow bAVM growth and potentially stabilize the rupture-prone abnormal vasculature.
PMCID: PMC3117949  PMID: 21437931
10.  The burden of prostate cancer in Asian nations 
In this review, the International Agency for Research on Cancer's cancer epidemiology databases were used to examine prostate cancer (PCa) age-standardized incidence rates (ASIR) in selected Asian nations, including Cancer Incidence in Five Continents (CI5) and GLOBOCAN databases, in an effort to determine whether ASIRs are rising in regions of the world with historically low risk of PCa development.
Materials and Methods:
Asian nations with adequate data quality were considered for this review. PCa ASIR estimates from CI5 and GLOBOCAN 2008 public use databases were examined in the four eligible countries: China, Japan, Korea and Singapore. Time trends in PCa ASIRs were examined using CI5 Volumes I-IX.
While PCa ASIRs remain much lower in the Asian nations examined than in North America, there is a clear trend of increasing PCa ASIRs in the four countries examined.
Efforts to systematically collect cancer incidence data in Asian nations must be expanded. Current CI5 data indicate a rise in PCa ASIR in several populous Asian countries. If these rates continue to rise, it is uncertain whether there will be sufficient resources in place, in terms of trained personnel and infrastructure for medical treatment and continuum of care, to handle the increase in PCa patient volume. The recommendation by some experts to initiate PSA screening in Asian nations could compound a resource shortfall. Obtaining accurate estimates of PCa incidence in these countries is critically important for preparing for a potential shift in the public health burden posed by this disease.
PMCID: PMC3327049  PMID: 22529743
Age-standardized incidence rate; Asia; cancer incidence in five continents; GLOBOCAN; prostate cancer
11.  Angiopoietin-Like 4 (ANGPTL4) Gene Polymorphisms and Risk of Brain Arteriovenous Malformations 
Brain arteriovenous malformations (BAVM) are high-flow vascular lesions prone to intracranial hemorrhage (ICH). Abnormal angiogenesis is a key characteristic of BAVM tissue. Angiopoietin-like 4 (ANGPTL4), a secreted glycoprotein, is thought to be involved in angiogenesis and required for proper postnatal blood vessel partitioning. We investigated whether common single nucleotide polymorphisms (SNPs) in ANGPTL4 were associated with risk of BAVM or ICH.
Methods and Results
We conducted a case-control study of 216 Caucasian BAVM cases and 246 healthy controls, and a secondary case-only analysis, comparing 83 ruptured (ICH) with 133 unruptured BAVM cases at presentation. Four tagSNPs in ANGPTL4 captured variation over a 10-kb region (rs2278236, rs1044250, rs11672433, and rs1808536) and were tested for association with BAVM or ICH. The minor allele (A) of rs11672433 (exon 6, Pro389Pro) was associated with an increased risk of BAVM (p = 0.006), which persisted after adjusting for multiple comparisons (p = 0.03). After adjustments for age and sex, carriers of the minor allele (A) remained at higher risk for BAVM compared to noncarriers (odds ratio, OR = 1.56; 95% confidence interval, CI = 1.01–2.41; p = 0.046) and risk of BAVM was increased with increasing copy of the minor A allele (OR = 1.49, 95% CI = 1.03–2.15; ptrend = 0.03). Five common haplotypes (frequency >1%) were inferred; overall haplotype distribution differed between BAVM cases and controls (χ2 = 12.2, d.f. = 4, p = 0.02). Neither SNPs (p > 0.05) nor haplotype distribution (χ2 = 1.1, d.f. = 4, p = 0.89) were associated with risk of ICH among BAVM cases.
A synonymous SNP in ANGPTL4 and haplotypes carrying it are associated with risk of BAVM but not with ICH presentation in BAVM cases.
PMCID: PMC3030504  PMID: 21212665
Arteriovenous malformations; Cerebrovascular disorders; Epidemiology; Genetics; Intracranial hemorrhage
12.  Evidence of endothelial progenitor cells in the human brain and spinal cord arteriovenous malformations 
Neurosurgery  2010;67(4):1029-1035.
Brain and spinal cord arteriovenous malformations (AVMs) are characterized by aberrant angiogenesis and vascular remodeling. Endothelial progenitor cells (EPCs) can be recruited by stromal cell-derived factor-1 (SDF-1), and participate in vascular remodeling in both physiological and pathological settings. We hypothesized that there was increased EPC levels in the brain and spinal cord AVM nidus.
Microsurgical specimens without endovascular embolization and radiosurgery from the brain (n=12) and spinal cord (n=5) AVMs were examined. Hemangioblastoma, meningioma, cerebral cortex obtained from epilepsy surgery, and the basilar artery (BA) from the autopsy were chosen for control comparisons. EPCs were identified as cells that were double-positive for the stem cell marker CD133 and the endothelial cell marker VEGFR-2 (vascular endothelial growth factor receptor-2 or KDR). In addition, SDF-1 was characterized by immunohistochemistry.
Both brain and spinal AVM tissues displayed more CD133, SDF-1, and CD68-positive signals than epilepsy and basilar artery control tissues. The level of EPCs was increased in the brain and spinal cord AVM nidus, mainly at the edge of the vessel wall. The expression of SDF-1 was co-localized with CD31-positive and α-smooth muscle cells, and was predominantly found within the vessel wall.
Our data demonstrate that EPCs are present in the nidus of the brain and spinal cord AVMs, which may mediate pathological vascular remodeling and impact the clinical course of AVMs.
PMCID: PMC2949301  PMID: 20881566
Angiogenesis; Endothelial progenitor cell; Stromal cell-derived factor-1; Vascular malformation
13.  Prostate cancer gene expression signature of patients with high body mass index 
The goal of this study was to evaluate prostate cancer gene expression signatures associated with elevated body mass index (BMI). Global gene expression profiles of prostate tumor cells and matching normal epithelial cells were compared between patients with features of normal- and high BMI at the time of radical prostatectomy. Knowledge-based analyses revealed an association of high BMI with altered levels of lipid metabolism and cholesterol homeostasis genes, such as stearoyl-CoA desaturase 1 (SCD1) and insulin-induced gene 1 (INSIG1), respectively, in prostate tumor cells. These genes were connected to known pathways of tumorigenesis revealed by the v-maf (musculoaponeurotic fibrosarcoma) oncogene homolog (MAF), notch receptor ligand, jagged 1 (JAG1), and the alanyl aminopeptidase (ANPEP/CD13) genes. This study highlighted that SCD1, a known target of statins, may play a mechanistic role in the recently noted beneficial effects of statin treatment in reducing biochemical recurrence of prostate cancer. An additional finding of our study is that some of the obesity related genes were upregulated in tumor-matched normal cells within the high BMI group, when compared to normal cells within the normal BMI cohort.
PMCID: PMC3059752  PMID: 21060327
body mass index; prostate cancer; gene expression; microarray; obesity; lipid metabolism; statins
14.  Racial/Ethnic Patterns in Prostate Cancer Outcomes in an Active Surveillance Cohort 
Prostate Cancer  2011;2011:234519.
Introduction. Concern regarding overtreatment of prostate cancer (CaP) is leading to increased attention on active surveillance (AS). This study examined CaP survivors on AS and compared secondary treatment patterns and overall survival by race/ethnicity. Methods. The study population consisted of CaP patients self-classified as black or white followed on AS in the Center for Prostate Disease Research (CPDR) multicenter national database between 1989 and 2008. Secondary treatment included radical prostatectomy (RP), external beam radiation therapy or brachytherapy (EBRT-Br), and hormone therapy (HT). Secondary treatment patterns and overall survival were compared by race/ethnicity. Results. Among 886 eligible patients, 21% were black. Despite racial differences in risk characteristics and secondary treatment patterns, overall survival was comparable across race. RP following AS was associated with the longest overall survival. Conclusion. Racial disparity in overall survival was not observed in this military health care beneficiary cohort with an equal access to health care.
PMCID: PMC3195388  PMID: 22096650
15.  Endothelial progenitor cell transplantation improves long-term outcome in mice 
Annals of neurology  2010;67(4):488-497.
Endothelial progenitor cells (EPCs) have been implicated in playing an important role in vascular repair and revascularization in ischemic organs including brain tissue. However, the cause of EPC migration and the function of EPC playing following post-ischemia are unclear. Here, we reported EPC therapy in a mouse model of transient middle cerebral artery occlusion (tMCAO) to explore the roles of EPC following ischemic brain injury.
Human EPCs were cultured, characterized, and confirmed with flow cytometry. Ex vivo expanded EPCs (1×106) were injected via jugular vein after 1 hour of tMCAO. Histological and behavioral analyses were performed from day 1 to 28 days after tMCAO.
EPCs were detected in ischemic brain region 24 hours after MCAO. EPC transplantation significantly reduced ischemic infarct volume at 3 days following MCAO compared to the control (p<0.05). CXCR4 was expressed on majority of EPCs and SDF-1-induced EPC migration was blocked by AMD3100 in vitro. SDF-1 was up-regulated in ischemic brain and AMD3100 could reduce EPCs migration to the ischemic region in vivo, suggesting that SDF-1/CXCR4 was involved in EPC-mediated neuroprotection. Compared to the control, EPC therapy reduced mouse cortex atrophy 4 weeks after tMCAO, which was accompanied by improved neurobehavioral outcomes (p<0.05). In addition, EPC injection potently increased angiogenesis in the peri-infarction area (p<0.05).
We conclude that systemic delivery of EPC protect against cerebral ischemic injury, promote neurovascular repair, and improve long-term neurobehavioral outcomes. Our data suggests that SDF-1/CXCR4 plays a critical role in EPC-mediated neuroprotection.
PMCID: PMC3026588  PMID: 20437584
angiogenesis; EPCs; ischemia; mice; neuroprotection
16.  ERG oncogene modulates prostaglandin signaling in prostate cancer cells 
Cancer Biology & Therapy  2011;11(4):410-417.
Androgen dependent induction of the eTs related gene (ERG) expression in more than half of all prostate cancers results from gene fusions involving regulatory sequence of androgen regulated genes (i.e., TMPRSS2, SLC45A3 and NDRG1) and protein coding sequence of the ERG. Emerging studies in experimental models underscore the functions of ERG in prostate tumorigenesis. however, biological and biochemical functions of ERG in prostate cancer (Cap) remain to be elucidated. This study suggests that ERG activation plays a role in prostaglandin signaling because knockdown of ERG expression in TMPRSS2-ERG fusion containing Cap cells leads to altered levels of the 15-hydroxy-prostaglandin dehydrogenase (HPGD), a tumor suppressor and prostaglandin catabolizing enzyme and prostaglandin E2 (PGE2). We demonstrate that HPGD expression is regulated by the binding of the ERG protein to the core promoter of this gene. Moreover, prostaglandin E2 dependent cell growth and urokinase-type plasminogen activator (uPA) expression are also affected by ERG knockdown. Together, these data imply that the ERG oncoprotein in CaP cells positively influence prostaglandin mediated signaling, which may contribute to tumor progression.
PMCID: PMC3047110  PMID: 21178489
prostate; cancer; ETS; ERG; TMPRSS2; oncogene; HPGD; tumor suppressor; prostaglandin; inflammation
17.  Notch-1 signalling is activated in brain arteriovenous malformations in humans 
Brain  2009;132(12):3231-3241.
A role for the Notch signalling pathway in the formation of arteriovenous malformations during development has been suggested. However, whether Notch signalling is involved in brain arteriovenous malformations in humans remains unclear. Here, we performed immunohistochemistry on surgically resected brain arteriovenous malformations and found that, compared with control brain vascular tissue, Notch-1 signalling was activated in smooth muscle and endothelial cells of the lesional tissue. Western blotting showed an activated form of Notch-1 in brain arteriovenous malformations, irrespective of clinical presentation and with or without preoperative embolization, but not in normal cerebral vessels from controls. In addition, the Notch-1 ligands Jagged-1 and Delta-like-4 and the downstream Notch-1 target Hes-1 were increased in abundance and activated in human brain arteriovenous malformations. Finally, increased angiogenesis was found in adult rats treated with a Notch-1 activator. Our findings suggest that activation of Notch-1 signalling is a phenotypic feature of brain arteriovenous malformations, and that activation of Notch-1 in normal vasculature induces a pro-angiogenic state, which may contribute to the development of vascular malformations.
PMCID: PMC2792368  PMID: 19812212
Notch-1; AVM; human; brain; signalling; angiogenesis
18.  EPH Receptor B4 (EPHB4) Gene Polymorphisms and Risk of Intracranial Hemorrhage in Patients with Brain Arteriovenous Malformations 
Brain arteriovenous malformations (BAVM) are a tangle of abnormal vessels directly shunting blood from the arterial to venous circulation and an important cause of intracranial hemorrhage (ICH). EphB4 is involved in arterial-venous determination during embryogenesis; altered signaling could lead to vascular instability resulting in ICH. We investigated the association of single-nucleotide polymorphisms (SNPs) and haplotypes in EPHB4 with risk of ICH at clinical presentation in BAVM patients.
Methods and Results
Eight haplotype-tagging SNPs spanning ∼29 kb were tested for association with ICH presentation in 146 Caucasian BAVM patients (phase I: 56 ICH, 90 non-ICH) using allelic, haplotypic, and principal components analysis. Associated SNPs were then genotyped in 102 additional cases (phase II: 37 ICH, 65 non-ICH) and data combined for multivariable logistic regression. Minor alleles of 2 SNPs were associated with reduced risk of ICH presentation (rs314313 C, P=0.005; rs314308 T, P=0.0004). Overall, haplotypes were also significantly associated with ICH presentation (χ2=17.24, 6 df, P=0.008); 2 haplotypes containing the rs314308 T allele (GCCTGGGT, P=0.003; GTCTGGGC, P=0.036) were associated with reduced risk. In principal components analysis, 2 components explained 91% of the variance, and complemented haplotype results by implicating 4 SNPs at the 5′ end, including rs314308 and rs314313. These 2 SNPs were replicated in the phase II cohort, and combined data resulted in greater significance (rs314313, P=0.0007; rs314308, P=0.00008). SNP association with ICH presentation persisted after adjusting for age, sex, BAVM size, and deep venous drainage.
EPHB4 polymorphisms are associated with risk of ICH presentation in BAVM patients, warranting further study.
PMCID: PMC2939745  PMID: 20031623
cerebrovascular disorders; genetics; hemorrhage; receptors; risk factors
19.  Postischemic IGF-1 gene transfer promotes neurovascular regeneration after experimental stroke 
Promoting neural regeneration after cerebral infarction has emerged as a potential approach for the treatment of stroke. Insulin-like growth factor 1 (IGF-1) possesses both neurotrophic and angiogenic properties. The aim of this study is to determine whether postischemic gene transfer of IGF-1 enhances neurovascular regeneration in a mouse model of permanent focal cerebral ischemia. Long-term cerebral IGF-1 overexpression was achieved with adeno-associated viral vector (AAV) via stereotaxic injection at 24 h after stroke. AAV-GFP or saline was injected as control. The success of postischemic gene transduction was confirmed by a strong green fluorescent protein signal and by increased IGF-1 protein expression in the peri-infarct region. Postischemic gene transfer of IGF-1 significantly enhanced vascular density at 8 weeks post stroke in the peri-infarct and injection needle tract area compared to AAV-GFP or saline treatment, as shown by immunohistochemical staining with vascular marker lectin. Furthermore, increased vascular density was associated with improved local vascular perfusion. Immunohistochemical staining with neuronal progenitor marker DCX and cell proliferation marker BrdU indicated that AAV-IGF-1 treatment potently increased neurogenesis compared to AAV-GFP injection. These data demonstrate that postischemic treatment of IGF-1 effectively promoted neural and vascular regeneration in the chronic stage of cerebral infarction.
PMCID: PMC2763573  PMID: 19513085
angiogenesis; IGF-1; neurovascular; regeneration; stroke
20.  Quantitative Expression of TMPRSS2 Transcript in Prostate Tumor Cells Reflects TMPRSS2-ERG Fusion Status 
TMPRSS2-ERG fusion is the most common oncogenic rearrangement in prostate cancer (CaP). Due to this chromosomal rearrangement one TMPRSS2 allele loses its promoter, and one of the ERG alleles gains that promoter leading to its overexpression in these tumor cells. Some studies suggest that TMPRSS2, an androgen regulated type II trans-membrane serine protease, may have an effect on CaP progression. We hypothesized that a difference in TMPRSS2 expression may be present in vivo between CaP cells with and without TMPRSS2-ERG fusion, or a compensatory mechanism for the allelic loss of TMPRSS2 may balance that expression difference. Therefore, TMPRSS2 mRNA expression was evaluated in micro-dissected CaP cells with and without TMPRSS2-ERG fusion in 132 CaP patients and analyzed for its correlation with other androgen receptor (AR) regulated genes and clinico-pathologic features. In vivo TMPRSS2 expression correlated with that of other AR-regulated genes, including PSA/KLK3 and PMEPA1, offering potential as AR surrogates. A significantly reduced expression of TMPRSS2 was evident in malignant cells harboring TMPRSS2-ERG fusion, but not in CaP cells without TMPRSS2-ERG fusion, further defining these two genetically distinct types of CaP.
PMCID: PMC2820150  PMID: 19597533
prostate cancer; TMPRSS2; quantitative expression; TMPRSS2-ERG fusion
21.  Soluble Endoglin Modulates Aberrant Cerebral Vascular Remodeling 
Annals of neurology  2009;66(1):19-27.
Brain arteriovenous malformations (AVMs) are an important cause of neurological morbidity in young adults. The pathophysiology of these lesions is poorly understood. A soluble form of endoglin (sEng) has been shown to cause endothelial dysfunction and induce preeclampsia. We tested if sEng would be elevated in brain AVM tissues relative to epilepsy brain tissues, and also investigated whether sEng overexpression via gene transfer in the mouse brain would induce vascular dysplasia and associated changes in downstream signaling pathways.
Expression levels of sEng in surgical specimens were determined by Western blot assay and ELISA. Vascular dysplasia, levels of MMP and oxidative stress were determined by immunohistochemistry and gelatin zymography.
Brain AVMs (n=33) had higher mean sEng levels (245 ± 175 vs 100 ± 60, % of control, P=0.04) compared with controls (n=8), as determined by Western blot. In contrast, membrane-bound Eng was not significantly different (108 ± 79 vs 100 ± 63, % of control, P=0.95). sEng gene transduction in the mouse brain induced abnormal vascular structures. It also increased matrix metalloproteinase (MMP) activity by 490 ± 30% (MMP-9), 220 ± 30% (MMP-2), and oxidants by 260 ± 20% (4-hydroxy-2-nonenal) at 2 weeks after injection, suggesting that MMPs and oxidative radicals may mediate sEng-induced pathological vascular remodeling.
The results suggest that elevated sEng may play a role in the generation of sporadic brain AVMs. Our findings may provide new targets for therapeutic intervention for patients with brain AVMs.
PMCID: PMC2773229  PMID: 19670444
22.  Evaluation of the 8q24 prostate cancer risk locus and MYC expression 
Cancer research  2009;69(13):5568-5574.
Polymorphisms at 8q24 are robustly associated with prostate cancer risk. The risk variants are located in non-protein coding regions and their mechanism has not been fully elucidated. To further dissect the function of this locus, we tested two hypotheses: i) unannotated microRNAs are transcribed in the region, and that ii) this region is a cis-acting enhancer. Using next generation sequencing, 8q24 risk regions were interrogated for known and novel microRNAs (miRNAs) in histologically normal radical prostatectomy (RP) tissue. We also evaluated the association between the risk variants and transcript levels of multiple genes, focusing on the proto-oncogene, MYC. RNA expression was measured in histologically normal and tumor tissue from 280 RP specimens (from 234 European American and 46 African American patients), and paired germline DNA from each individual was genotyped for six 8q24 risk SNPs. No evidence was found for significant miRNA transcription within 8q24 prostate cancer risk loci. Likewise, no convincing association between distal RNA expression and risk allele status was detected in either histologically normal or tumor tissue. To our knowledge, this is one of the first and largest studies to directly assess miRNA in this region and to systematically measure MYC expression levels in prostate tissue in relation to inherited risk variants. These data will help to direct the future study of this risk locus.
PMCID: PMC2884104  PMID: 19549893
23.  Development of a Two-part Strategy to Identify a Therapeutic Human Bispecific Antibody That Inhibits IgE Receptor Signaling* 
The Journal of Biological Chemistry  2010;285(27):20850-20859.
The development of bispecific antibodies as therapeutic agents for human diseases has great clinical potential, but broad application has been hindered by the difficulty of identifying bispecific antibody formats that exhibit favorable pharmacokinetic properties and ease of large-scale manufacturing. Previously, the development of an antibody technology utilizing heavy chain knobs-into-holes mutations and a single common light chain enabled the small-scale generation of human full-length bispecific antibodies. Here we have extended the technology by developing a two-part bispecific antibody discovery strategy that facilitates proof-of-concept studies and clinical candidate antibody generation. Our scheme consists of the efficient small-scale generation of bispecific antibodies lacking a common light chain and the hinge disulfides for proof-of-concept studies coupled with the identification of a common light chain bispecific antibody for large-scale production with high purity and yield. We have applied this technology to generate a bispecific antibody suitable for development as a human therapeutic. This antibody directly inhibits the activation of the high affinity IgE receptor FcϵRI on mast cells and basophils by cross-linking FcϵRI with the inhibitory receptor FcγRIIb, an approach that has strong therapeutic potential for asthma and other allergic diseases. Our approach for producing human bispecific full-length antibodies enables the clinical application of bispecific antibodies to a validated therapeutic pathway in asthma.
PMCID: PMC2898330  PMID: 20444694
Antibodies; Inflammation; Mast Cell; Protein Purification; Signal Transduction; Asthma; IgE
24.  Brain arteriovenous malformation biology relevant to hemorrhage and implication for therapeutic development 
Stroke; a journal of cerebral circulation  2008;40(3 Suppl):S95-S97.
Brain arteriovenous malformations (AVM) cause intracranial hemorrhage (ICH). Molecular characterization of lesional tissue implicates angiogenic (VEGF, ANG-2, MMP-9) and inflammatory (cytokines and chemokines) pathways, but the pathogenesis remain obscure and medical therapy is lacking. Macrophage and neutrophil invasion has also been observed in the absence of prior ICH. Single nucleotide polymorphisms (SNPs) in interleukin-1β (IL-1β) and activin receptor-like kinase-1 (ALK-1) are associated with AVM susceptibility, and SNPs in IL-1β, IL-6, TNF-α and APOE are associated with AVM rupture. These observations suggest that even without a complete understanding of the determinants of AVM development, the recent discoveries of downstream derangements in vascular function and integrity may offer potential targets for therapy development. Further, biomarkers can be established for assessing ICH risk. Finally, these data will aid in development of model systems for mechanistic testing, by development of surrogate phenotypes (microvascular dysplasia) and/or models recapitulating the clinical syndrome of recurrent spontaneous ICH.
PMCID: PMC2677752  PMID: 19064791
angiogenesis; inflammation; vascular malformations
25.  Overexpression of Netrin-1 Induces Neovascularization in the Adult Mouse Brain 
Netrin-1 is a critical molecule for axonal pathfinding during embryo development, and because of its structural homology to the endothelial mitogens, it may share its effects on vascular network formation. Using an adeno-associated viral netrin-1 vector (AAV-NT-1) gene transfer, we demonstrated that netrin-1 was able to stimulate the proliferation and migration of human cerebral endothelial cells (HCECs) and human aortic smooth muscle cells (HASMCs) compared to the control (p<0.05), and could also promote HCEC tube formation on matrigel (p<0.05) in vitro. Moreover, netrin-1 hyper-stimulation could promote focal neovascularization (p<0.05) in the adult brain in vivo. Unlike VEGF-induced microvessel increase, Netrin-1-induced newly formed vessels that showed an artery-like phenotype, with an intact endothelial cell monolayer surrounded by multiple cell layers, including smooth muscle cells and an astrocyte-connected outer layer. Our findings suggest that netrin-1 plays an important role in promoting blood vessel formation in the adult rodent central nervous system, and could have broad implication in cerebrovascular development and remodeling.
PMCID: PMC2581494  PMID: 18461079
adeno-associated viral vector; angiogenesis; brain; mouse; netrin-1; neovascularization; vascular endothelial growth factor

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