EMP2 is a novel therapeutic target for endometrial cancer stem cells.

Previous studies have suggested that overexpression of the oncogenic protein epithelial membrane protein-2 (EMP2) correlates with endometrial carcinoma progression and ultimately poor survival from disease. To understand the role of EMP2 in the etiology of disease, gene analysis was performed to show transcripts that are reciprocally regulated by EMP2 levels. In particular, EMP2 expression correlates with and helps regulate the expression of several cancer stem cell associated markers including aldehyde dehydrogenase 1 (ALDH1). ALDH expression significantly promotes tumor initiation and correlates with the levels of EMP2 expression in both patient samples and tumor cell lines. As therapy against cancer stem cells in endometrial cancer is lacking, the ability of anti-EMP2 IgG1 therapy to reduce primary and secondary tumor formation using xenograft HEC1A models was determined. Anti-EMP2 IgG1 reduced the expression and activity of ALDH and correspondingly reduced both primary and secondary tumor load. Our results collectively suggest that anti-EMP2 therapy may be a novel method of reducing endometrial cancer stem cells.

EMP2 regulates angiogenesis in endometrial cancer cells through induction of VEGF.

Understanding tumor-induced angiogenesis is a challenging problem with important consequences for the diagnosis and treatment of cancer. In this study, we define a novel function for epithelial membrane protein-2 (EMP2) in the control of angiogenesis. EMP2 functions as an oncogene in endometrial cancer, and its expression has been linked to decreased survival. Using endometrial cancer xenografts, modulation of EMP2 expression resulted in profound changes to the tumor microvasculature. Under hypoxic conditions, upregulation of EMP2 promoted vascular endothelial growth factors (VEGF) expression through a HIF-1α-dependent pathway and resulted in successful capillary-like tube formation. In contrast, reduction of EMP2 correlated with reduced HIF-1α and VEGF expression with the net consequence of poorly vascularized tumors in vivo. We have previously shown that targeting of EMP2 using diabodies in endometrial cancer resulted in a reduction of tumor load, and since then we have constructed a fully human EMP2 IgG1. Treatment of endometrial cancer cells with EMP2-IgG1 reduced tumor load with a significant improvement in survival. These results support the role of EMP2 in the control of the tumor microenvironment and confirm the cytotoxic effects observed by EMP2 treatment in vivo.

Orbital inflammatory disease: a diagnostic and therapeutic challenge.

The spectrum of orbital inflammatory disease (OID) ranges broadly from specific disease diagnoses, for example, Wegener's granulomatosis or sarcoidosis, to nonspecific inflammation which may involve one or multiple structures of the orbit. Mimics of idiopathic OID must be considered in a comprehensive differential diagnosis and include malignancies, congenital mass lesions, infectious diseases, and occult or distant trauma. Idiopathic OID may be secondary to an underlying systemic inflammatory disease, which must be diagnosed in order to develop a comprehensive therapeutic plan, or may represent localized pathologic processes without systemic involvement. Evaluation of the patient with suspected OID must include a careful history, physical examination, directed laboratory, and radiologic studies, and may sometimes require tissue for diagnostic studies. Therapeutic options for inflammatory diseases are expanding as biologically targeted agents become available that act on specific segments of the inflammatory cascades. The purpose of this paper is to provide a framework for the evaluation and management of patients with the spectrum of diseases known as OID and to discuss some of the new advances in immunologic monitoring and targeted immune therapies that will likely play an increasingly important role in the care of these patients.

Doxycycline and intracranial hypertension.

The authors report seven patients from six neuro-ophthalmology referral centers who developed pseudo-tumor cerebri during treatment with doxycycline. All four female patients and one of three male patients were obese. Vision was minimally affected in most patients, but two had substantial visual acuity or visual field loss at presentation. Discontinuation of doxycycline, with or without additional intracranial pressure-lowering agents, yielded improvement, but permanent visual acuity or visual field loss occurred in five patients.

Role of extracellular peroxidase in the superoxide production by wheat root cells.

Extracellular peroxidase has been shown to contribute to superoxide production in wounded wheat (Triticum aestivum L. cv. Ljuba) root cells. The superoxide-synthesizing system of root cells was considerably inhibited by KCN and NaN3 and activated by MnCl2 and H2O2. Treatment of roots with salicylic acid and a range of di- and tri-carbonic acids (malic, citric, malonic, fumaric, and succinic acids) stimulated superoxide production in both root cells and extracellular solution. The H2O2-stimulated superoxide production in the extracellular solution was much higher when roots were preincubated with salicylic or succinic acid. Exogenous acids enhanced peroxidase activity in the extracellular solution. Pretreatment of root cells with the detergents trypsin and sodium dodecyl sulfate had similar effects on the peroxidase activity. Significant inhibition of both superoxide production and peroxidase activity by diphenylene iodonium suggests that the specificity of the latter as an inhibitor of NADPH oxidase is doubtful. Results obtained indicate that extra-cellular peroxidase is involved in the superoxide production in wheat root cells. The mobile form of peroxidase can be readily secreted to the apoplastic solution and serve as an emergency enzyme involved in plant wound response.

Molecular cloning of a Bacteroides caccae TonB-linked outer membrane protein identified by an inflammatory bowel disease marker antibody.

Commensal enteric bacteria are a required pathogenic factor in inflammatory bowel disease (IBD), but the identity of the pertinent bacterial species is unresolved. Using an IBD-associated pANCA monoclonal antibody, a 100-kDa protein was recently characterized from an IBD clinical isolate of Bacteroides caccae (p2Lc3). In this study, consensus oligonucleotides were designed from 100-kDa peptides and used to identify a single-copy gene from the p2Lc3 genome. Sequence analysis of the genomic clone revealed a 2,844-bp (948 amino acid) open reading frame encoding features typical of the TonB-linked outer membrane protein family. This gene, termed ompW, was detected by Southern analysis only in B. caccae and was absent in other species of Bacteroides and gram-negative coliforms. The closest homologues of OmpW included the outer membrane proteins SusC of Bacteroides thetaiotaomicron and RagA of Porphyromonas gingivalis. Recombinant OmpW protein was immunoreactive with the monoclonal antibody, and serum anti-OmpW immunoglobulin A levels were elevated in a Crohn's disease patient subset. These findings suggest that OmpW may be a target of the IBD-associated immune response and reveal its structural relationship to a bacterial virulence factor of P. gingivalis and periodontal disease.

Ocular pANCA antigens are expressed in nonpigmented ciliary body epithelium and are conserved in multiple mammalian species.

PURPOSE: pANCA marker autoantibody is expressed by a subset of patients with anterior uveitis. A recombinantly isolated pANCA monoclonal antibody, Fab 5-3, identifies ocular expression of corresponding pANCA antigens in human ciliary body and retina. In this study, Fab 5-3 was used to explore pANCA antigen expression in ocular tissues of multiple mammalian species and identify the ciliary body cell type expressing the pANCA antigen. METHODS: Ocular tissues were obtained from several mammalian species and evaluated for expression of the pANCA (Fab 5-3) antigen(s) using immunohistochemistry and Western analysis of tissue extracts. Additionally, primary cultures of nonpigmented and pigmented rabbit ciliary body epithelium were analyzed for pANCA expression using immunofluorescence and Western analysis. RESULTS: Ocular pANCA (Fab 5-3) antigen expression was observed by immunohistochemistry only in the cytoplasm of retinal ganglion cells and ciliary body epithelium. Retinal antigen expression was conserved in all species examined. Ciliary body expression was observed in human, rabbit, rat, and mouse, but not in pig or cow. Antigen expression in the rabbit ciliary body was restricted to the nonpigmented layer as defined in primary cultures of nonpigmented and pigmented ciliary body epithelium. Immunoreactive proteins in both the human and rabbit included a 32-33 kDa doublet (histone H1), and novel 80 and 100 kDa proteins. CONCLUSIONS: This study identifies ocular pANCA antigen expression in multiple mammalian species localized to the retinal ganglion cell layer and the non-pigmented ciliary body epithelium. The present study also establishes novel 80 and 100 kDa proteins which may correspond to the cytoplasmic antigens detected in situ and can be further characterized biochemically and immunologically using small animal model systems.

Colonic bacteria express an ulcerative colitis pANCA-related protein epitope.

Bacteria are a suspected pathogenic factor in inflammatory bowel disease, but the identity of the relevant microbial species remains unresolved. The pANCA autoantibody is associated with most cases of ulcerative colitis (UC) and hence reflects an immune response associated with the disease process. This study addresses the hypothesis that pANCA identifies an antigen(s) expressed by bacteria resident in the human colonic mucosa. Libraries of colonic bacteria were generated using aerobic and anaerobic microbiologic culture conditions, and bacterial pools and clonal isolates were evaluated for cross-reactive antigens by immunoblot analysis using the pANCA monoclonal antibody Fab 5-3. Two major species of proteins immunoreactive to pANCA monoclonal antibodies were detected in bacteria from the anaerobic libraries. Colony isolates of the expressing bacteria were identified as Bacteroides caccae and Escherichia coli. Isolation and partial sequencing of the B. caccae antigen identified a 100-kDa protein without database homologous sequences. The E. coli protein was biochemically and genetically identified as the outer membrane porin OmpC. Enzyme-linked immunosorbent assay with human sera demonstrated elevated immunoglobulin G anti-OmpC in UC patients compared to healthy controls. These findings demonstrate that a pANCA monoclonal antibody detects a recurrent protein epitope expressed by colonic bacteria and implicates colonic bacterial proteins as a target of the disease-associated immune response.

Identification of histone H1 as a cognate antigen of the ulcerative colitis-associated marker antibody pANCA.

Perinuclear anti-neutrophil cytoplasmic antibody (pANCA)(4)is a predominant serum marker of ulcerative colitis (UC), and a familial trait associated with disease susceptibility and disease associated MHC haplotypes. This study characterizes the pANCA antigen defined by representative UC-pANCA human monoclonal antibodies, Fab 5-3 and 5-2. Western blot analysis probed with Fab 5-3 revealed specific binding to a nuclear protein doublet (apparent MW=32-33 kDa) expressed in several cell types. Purification and tryptic peptide sequencing identified the protein as histone H1, and this specificity was confirmed by Fab 5-3 binding to purified H1. Rabbit anti-histone H1 immunostaining and Western blot analysis confirmed that the pANCA epitope is preferentially immunoaccessible in polymorphonuclear neutrophils (PMN). The epitope was localized to the COOH-terminal region by site-specific proteolysis, and recombinant deletants further localized binding activity for both Fab 5-2 and 5-3 to two non-overlapping segments (AA 69-171 and 172-226) associated with a recurring PKKAK motif. Serum IgG binding was detectable to these segments, but was not significantly correlated with pANCA titer or disease status. These findings indicate that histone H1 bears a recurring COOH-terminal epitope recognized by monoclonal ulcerative colitis-associated pANCA marker antibodies, but this epitope is not a predominant specificity of serum pANCA.

Mast cell and neuroendocrine cytoplasmic autoantigen(s) detected by monoclonal pANCA antibodies.

pANCA is a marker antibody expressed in most patients with ulcerative colitis, and its cognate antigen is potentially an immunologic target in this disease. This study evaluates whether pANCA detects an autoantigen that is expressed in the colonic mucosa. Immunohistochemistry of colon specimens with human pANCA monoclonal antibodies (Fab 5-2 and 5-3) revealed a minor population of immunoreactive mucosal cells bearing a cytoplasmic vesicle antigen. By distribution, morphology, and tryptase expression, these were identified as mast cells. Immunofluorescent analysis revealed similar immunoreactivity of mouse mast cell lines and human KU812. Western analysis of mouse mast cell lines revealed immunoreactive proteins, and these were distinct from previously proposed pANCA antigens (histone H1, HMG 1 and 2, and neutrophil vesicle antigens). Cognate antigen for Fab 5-2 and 5-3 was also expressed in other tissue mast cells, cerebellar neurons, and pancreatic islet cells. These findings identify a novel cytoplasmic autoantigen(s) associated with UC by its presence in colonic mucosa and recognition by a disease-associated marker antibody.

Definition of ocular antigens in ciliary body and retinal ganglion cells by the marker antibody pANCA.

PURPOSE: A subset of patients with anterior uveitis express the marker, perinuclear anti-neutrophil cytoplasmic antibody (pANCA). In this study, recombinantly isolated pANCA monoclonal antibodies were used to search for ocular cells expressing the pANCA antigen. METHODS: Paraffin sections of human ocular tissues obtained after death were analyzed by immunohistochemistry to identify cell types expressing pANCA antigen. Microdissected eye-bank ocular tissue was characterized by western blot analysis to confirm antigen expression and identify candidate protein species. RESULTS: Immunohistochemical analysis with pANCA monoclonal antibodies revealed cytoplasmic antigen expression in retinal ganglion cells and ciliary body epithelium. pANCA antigen expression was restricted to tissues bearing these cell types by western blot analysis. A common set of epitope-positive protein species was shared by the two tissues (28 kDa, 80 kDa, and 90 kDa). Comparison of ocular tissues from seven subjects revealed no heterogeneity in antigen expression. CONCLUSIONS: In this study, novel cytoplasmic antigens of the pANCA marker antibody expressed in ciliary body and retinal tissue were identified. Validation of these antigens as targets of inflammation in pANCA+ uveitis requires further biochemical and immunologic analysis.

pANCA antibodies in patients with anterior uveitis: identification of a marker antibody usually associated with ulcerative colitis.

A pANCA autoantibody (antineutrophil cytoplasmic antibody, perinuclear pattern) has been described in uveitis patients, but its correlation with systemic illnesses and the specific type of pANCA has not been defined. The goals of this study were to determine the (1) frequency of pANCA autoantibodies in uveitis, (2) systemic associations in the pANCA + uveitis patients, and (3) type of pANCA antigen recognized by the uveitis-associated autoantibody. Serum was obtained from 59 patients with anterior uveitis or panuveitis and from nonuveitis controls. A detailed medical and family history was obtained from each subject at the time of phlebotomy. Sera were screened by neutrophil ELISA to determine the frequency of ANCA positivity. Immunofluorescence assays were then used to differentiate cANCA from pANCA. The specificity of the pANCA + antibodies was further characterized by DNase 1 sensitivity and granule antigen ELISAs. ANCA antibodies were detected in 29% of all patients with panuveitis or anterior uveitis. In 41% of these ANCA + patients, serum antibody detected a perinuclear antigen that was sensitive in all cases to DNase 1. The majority of pANCA + uveitis patients were either HLA-B27 positive or had systemic evidence of immune-mediated diseases. Two pANCA + patients had no medical or family history of other immune-mediated diseases. This study identifies a subset of uveitis patients distinguished by expression of a specific pANCA marker antibody. The characteristics of this antibody are similar to the pANCA antibody present in most patients with ulcerative colitis. Expression of the pANCA autoantibody in uveitis patients is a susceptibility marker for other immune-mediated diseases.

Phage display cloning and characterization of an immunogenetic marker (perinuclear anti-neutrophil cytoplasmic antibody) in ulcerative colitis.

Ulcerative colitis (UC) is genetically associated with a marker serum Ab (pANCA), identified by its reactivity with a neutrophil Ag. This study utilized phage display technology to clone and characterize pANCA, which has resisted conventional isolation strategies. Since spontaneous pANCA-secreting B cells are detectable in UC lamina propria lymphocytes, this cell source was used to construct a complete IgG1-kappa Ig library. Selection of phage by panning with fixed neutrophils yielded a 195-fold enrichment after five cycles of panning. BstN1 fingerprinting of the enriched library revealed two predominant clones, and DNA sequencing demonstrated highly homologous heavy and light chain variable region segments. Clones were reengineered to express soluble Fab, and neutrophil binding was verified by ELISA. Detailed studies with the two recombinant Fabs, NANUC-1 and -2, validated their identity with serum pANCAs by the criteria of immunofluorescence, confocal microscopy, and DNase I sensitivity. NANUC-1 and -2, like serum UC-pANCA, lack reactivity with previously characterized ANCA-reactive neutrophil proteins and thus detect a novel Ag(s). This study demonstrates the feasibility of selecting phage display Ab libraries on uncharacterized biologic substrates to isolate marker Abs of pathogenic importance.

Expression of a novel autoantibody defined by the VH3-15 gene in inflammatory bowel disease and Campylobacter jejuni enterocolitis.

This study newly introduces anti-VH mAbs to assess the role of clonal B cell activity in inflammatory bowel disease. Immunohistochemistry of colonic biopsies in ulcerative colitis (UC) and Crohn's disease (CD), but not unaffected individuals, demonstrated uniform staining of intravascular erythrocytes with BK2, a monoclonal specific for the VH3-15 Ig heavy chain gene product. Staining was caused by erythrocytes opsinized in vivo by anti-erythrocyte Abs present in patient sera and by using the VH3-15 gene product. The erythrocyte Ag was identified by immunoprecipitation as 22- and 28-kDa membrane proteins. A direct flow cytometric assay was developed to measure this serum autoantibody and was tested in 101 individuals with UC, CD, other acute or chronic colitis, and healthy controls. Compared with normal subjects, BK2+ anti-erythrocyte Abs were elevated in most sera from patients with CD and UC (including postcolectomy). BK2+ anti-erythrocyte Abs also were elevated in 10 of 38 noninflammatory bowel disease patients, all of whom had Campylobacter jejuni enterocolitis. These findings suggest that a common immunopathogenetic factor, manifested by VH3-15 B cell activation may be shared in UC, CD, and Campylobacter jejuni enterocolitis.