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.
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.
Arteriovenous Malformation; AVM
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.
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.
PATIENTS AND METHODS
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.
metastasis-free survival; natural history; overall survival; prostate cancer; PSA recurrence
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.
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.
Age-standardized incidence rate; Asia; cancer incidence in five continents; GLOBOCAN; prostate cancer
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.
Arteriovenous malformations; Cerebrovascular disorders; Epidemiology; Genetics; Intracranial hemorrhage
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.
Angiogenesis; Endothelial progenitor cell; Stromal cell-derived factor-1; Vascular malformation
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.
body mass index; prostate cancer; gene expression; microarray; obesity; lipid metabolism; statins
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.
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.
angiogenesis; EPCs; ischemia; mice; neuroprotection
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.
prostate; cancer; ETS; ERG; TMPRSS2; oncogene; HPGD; tumor suppressor; prostaglandin; inflammation
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.
Notch-1; AVM; human; brain; signalling; angiogenesis
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.
cerebrovascular disorders; genetics; hemorrhage; receptors; risk factors
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.
angiogenesis; IGF-1; neurovascular; regeneration; stroke
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.
prostate cancer; TMPRSS2; quantitative expression; TMPRSS2-ERG fusion
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.
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.
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.
Antibodies; Inflammation; Mast Cell; Protein Purification; Signal Transduction; Asthma; IgE
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.
angiogenesis; inflammation; vascular malformations
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.
adeno-associated viral vector; angiogenesis; brain; mouse; netrin-1; neovascularization; vascular endothelial growth factor
Developmental endothelial locus-1 (Del-1) is a novel angiomatrix protein that has been shown to stimulate a potent angiogenic response and promote functional recovery in hind limb and cardiac ischemia in animal models; however, its impact on cerebral angiogenesis is unknown. In this study, we investigated whether Del-1 overexpression via gene transfer induces cerebral angiogenesis in a murine model, and examined Del-1 expression after ischemic stroke. Cerebral Del1-1 overexpression was achieved with AAV (adeno-associated virus) transduction system via stereotactic injection. Control mice were injected with AAV-lacZ. Del-1gene transduction led to a significant induction of cerebral angiogenesis compared to AAV-lacZ treatment at 4 weeks after gene transfer (Del-1: 97±7 vs lacZ: 64±28, vessels/field, p<0.05). Mice transduced with AAV-Del- 1 showed significantly elevated vascular densities for up to 6 weeks after gene delivery. In addition, double immunofluorescent staining showed co-localization of endothelial cell marker CD31 with BrdU (specific marker for proliferating cells), indicating that Del-1 promoted endogenous endothelial cell proliferation and angiogenesis. Our immunohistochemcial staining also showed that Del-1 expression was markedly upregulated in the peri-infarct area at 3 days after permanent focal cerebral ischemia compared to the sham-operated non-ischemic control. Our data suggest that Del-1 may participate in modulating cerebral angiogenesis, and that gene transfer of Del-1 may provide a novel and potent means for stimulating cerebral angiogenesis.
Angiogenesis; Brain; Del-1; Gene transfer; Ischemia
Brain arteriovenous malformations (AVM) have high MMP-9, IL-6 and MPO expression, and polymorphic variations in inflammatory genes are associated with increased risk of hemorrhage. In this study, we characterized the presence of inflammatory cells in AVM lesional tissues.
Immunohistochemistry was used to identify and localize neutrophils (MPO as marker), macrophages/microglia (CD68 as marker), T lymphocytes (CD3 as marker), and B lymphocytes (CD20 as marker). Endothelial cell (EC) marker CD31 was used as an index to assess vascular mass (EC mass). Surgical specimens from 20 unruptured, non-embolized AVMs were examined; seven cortical samples from temporal lobectomy were used as controls. Positive signals for inflammatory cell markers were counted and analyzed by normalizing to the area of the tissue section and the amount of endothelial cells (cells/mm2/EC mass pixels). Levels of MPO and MMP-9 were determined by ELISA.
Neutrophils and macrophages are all frequently identified in the vascular wall of AVM tissues. In contrast, T and B lymphocytes are rarely observed in AVM tissues. AVM tissues displayed more neutrophil and macrophage/microglia markers than epilepsy control tissues (MPO: 434 ± 333 vs 5 ± 4, P=0.0001; CD68: 454 ± 404 vs 4 ± 2, P=0.0001; cells/mm2/EC mass pixels). In ex vivo studies, neutrophil quantity, MPO, and MMP-9 levels were all co-linear(R2=0.98–0.99).
Our study demonstrates that inflammatory cells are present in AVM tissues. Taken together with prior genetic and cytokine studies, these data are consistent with a novel view that inflammation is associated with AVM disease progression and rupture.
CD68; inflammation; myeloperoxidase; vascular malformations
Elevated activities of matrix metalloproteinases (MMPs) following ischemic stroke have been shown to mediate ischemic injury as well as neurovascular remodeling. The extracellular MMP inducer (EMMPRIN) is a 58-kDa cell surface glycoprotein, which has been known to play a key regulatory role for MMP activities. The roles of EMMPRIN in stroke injury are not clearly understood. In this study, we investigated changes of EMMPRIN in a mouse model of permanent focal cerebral ischemia, and examined potential association between EMMPRIN and MMP-9 expression. Adult male CD-1 mice were subjected to permanent focal ischemia by intraluminal occlusion of the left middle cerebral artery (MCAO) under anesthesia. EMMPRIN expression was markedly upregulated in the peri-infarct area at 2–7 days after ischemia compared to the contralateral non-ischemic hemisphere by Western blot analysis. Immunofluorescent double staining demonstrated that EMMPRIN signals co-localized with vwF-positive endothelial cells and GFAP-positive peri-vascular astrocytes. In contrast, EMMPRIN signal did not co-localize with NeuN-positive neurons, or MPO-positive neutrophils. Dual fluorescent staining revealed that EMMPRIN co-localized with MMP-9. Our data also demonstrated that increased EMMPRIN expression correlated with increased MMP-9 levels in a temporal manner.
In summary, we report for the first time that EMMPRIN expression was significantly increased in a mouse model of permanent focal cerebral ischemia. The spatial and temporal association between increased EMMPRIN expression and elevated MMP-9 levels suggest that EMMPRIN may modulate MMP-9 activity, and participate in neurovascular remodeling after ischemic stroke.
EMMPRIN; MMP-9; stroke
Overexpression of FGF receptor 3 (FGFR3) is implicated in the development of t(4;14)-positive multiple myeloma. While FGFR3 is frequently overexpressed and/or activated through mutations in bladder cancer, the functional importance of FGFR3 and its potential as a specific therapeutic target in this disease have not been elucidated in vivo. Here we report that inducible knockdown of FGFR3 in human bladder carcinoma cells arrested cell-cycle progression in culture and markedly attenuated tumor progression in xenografted mice. Further, we developed a unique antibody (R3Mab) that inhibited not only WT FGFR3, but also various mutants of the receptor, including disulfide-linked cysteine mutants. Biochemical analysis and 2.1-Å resolution crystallography revealed that R3Mab bound to a specific FGFR3 epitope that simultaneously blocked ligand binding, prevented receptor dimerization, and induced substantial conformational changes in the receptor. R3Mab exerted potent antitumor activity against bladder carcinoma and t(4;14)-positive multiple myeloma xenografts in mice by antagonizing FGFR3 signaling and eliciting antibody-dependent cell-mediated cytotoxicity (ADCC). These studies provide in vivo evidence demonstrating an oncogenic role of FGFR3 in bladder cancer and support antibody-based targeting of FGFR3 in hematologic and epithelial cancers driven by WT or mutant FGFR3.