Soluble trivalent engagers redirect cytolytic T cell activity toward tumor endothelial marker 1.

Tumor endothelial marker 1 (TEM1) is an emerging cancer target with a unique dual expression profile. First, TEM1 is expressed in the stroma and neo-vasculature of many human carcinomas but is largely absent from healthy adult tissues. Second, TEM1 is expressed by tumor cells of mesenchymal origin, notably sarcoma. Here, we present two fully human anti-TEM1 single-chain variable fragment (scFv) reagents, namely, 1C1m and 7G22, that recognize distinct regions of the extracellular domain and possess substantially different affinities. In contrast to other, well-described anti-TEM1 binders, these fragments confer cytolytic activity when expressed as 2 <sup>nd</sup> generation chimeric antigen receptors (CARs). Moreover, both molecules selectively redirect human T cell effector functions toward TEM1 <sup>+</sup> tumor cells when incorporated into experimental soluble bispecific trivalent engagers that we term TriloBiTEs (tBs). Furthermore, systemic delivery of 1C1m-tB prevents the establishment of Ewing sarcoma tumors in a xenograft model. Our observations confirm TEM1 as a promising target for cancer immunotherapy and illustrate the prospective translational potential of certain scFv-based reagents

Presence of an HO-1 expression threshold in renal glomeruli

This article reports data describing HO-1 expression patterns of heme oxygenase (HO)-1 in isolated rat glomeruli and in cultured glomerular epithelial cells (GEC) in response to its natural substrate heme. Qualitative and quantitative data are presented to support presence of a HO-1 expression threshold in glomeruli but not in GEC. Interpretation of our data and further insight into HO-1 expression pattern in glomeruli may be found in 'HO-1 expression control in the rat glomerulus' [1]. © 2015 Published by Elsevier Inc

Glomerular epithelial cells-targeted heme oxygenase-1 over expression in the rat: Attenuation of proteinuria in secondary but not primary injury

Background/Aims: Induction of heme oxygenase 1 (HO-1) in glomerular epithelial cells (GEC) in response to injury is poor and this may be a disadvantage. We, therefore, explored whether HO-1 overexpression in GEC can reduce proteinuria induced by puromycin aminonucleoside (PAN) or in anti-glomerular basement membrane (GBM) antibody (Ab)-mediated glomerulonephritis (GN). Methods: HO-1 overexpression in GEC (GECHO-1) of Sprague-Dawley rats was achieved by targeting a FLAG-human (h) HO-1 using transposon-mediated transgenesis. Direct GEC injury was induced by a single injection of PAN. GN was induced by administration of an anti-rat GBM Ab and macrophage infiltration in glomeruli was assessed by immunohistochemistry and western blot analysis, which was also used to assess glomerular nephrin expression. Results: In GECHO-1 rats, FLAG-hHO-1 transprotein was co-immunolocalized with nephrin. Baseline glomerular HO-1 protein levels were higher in GECHO-1 compared to wild type (WT) rats. Administration of either PAN or anti-GBM Ab to WT rats increased glomerular HO-1 levels. Nephrin expression markedly decreased in glomeruli of WT or GECHO-1 rats treated with PAN. In anti-GBM Ab-treated WT rats, nephrin expression also decreased. In contrast, it was preserved in anti-GBM Ab-treated GECHO-1 rats. In these, macrophage infiltration in glomeruli and the ratio of urine albumin to urine creatinine (Ualb/Ucreat) were markedly reduced. There was no difference in Ualb/Ucreat between WT and GECHO-1 rats treated with PAN. Conclusion: Depending on the type of injury, HO-1 overexpression in GEC may or may not reduce proteinuria. Reduced macrophage infiltration and preservation of nephrin expression are putative mechanisms underlying the protective effect of HO-1 overexpression following immune injury. © 2016 S. Karger AG, Basel

Heme Oxygenase 1 Up-Regulates Glomerular Decay Accelerating Factor Expression and Minimizes Complement Deposition and Injury

Complement-activation controllers, including decay accelerating factor (DAF), are gaining emphasis as they minimize injury in various dysregulated complement-activation disorders, including glomerulopathies. Heme oxygenase (HO)-1 overexpression or induction has been shown to attenuate injury in complement-dependent models of glomerulonephritis. This study investigated whether up-regulation of DAF by heme oxygenase 1 (HO-1) is an underlying mechanism by using Hmox-1–deficient rats (Hmox1+/−; Hmox1−/−) or rats with HO-1 overexpression targeted to glomerular epithelial cells (GECHO-1), which are particularly vulnerable to complement-mediated injury owing to their terminally differentiated nature. Constitutively expressed DAF was decreased in glomeruli of Hmox1−/− rats and augmented in glomeruli of GECHO-1 rats. In GECHO-1 rats with anti–glomerular basement membrane antibody mediated, complement-dependent injury, complement component C3 fragment b (C3b) deposition was reduced, whereas proteinuria was diminished. In glomeruli of wild-type rats, the natural Hmox substrate, hemin, induced glomerular DAF. This effect was attenuated in glomeruli of Hmox1−/− rats and augmented in glomeruli of GECHO-1 rats. Hemin analogues differing in either metal or porphyrin ring functionalities, acting as competitive Hmox-substrate inhibitors, also increased glomerular DAF and reduced C3b deposition after spontaneous complement activation. In the presence of a DAF-blocking antibody, the reduction in C3b deposition was reversed. These observations establish HO-1 as a physiologic regulator of glomerular DAF and identify hemin analogues as inducers of functional glomerular DAF able to minimize C3b deposition. © 2016 American Society for Investigative Patholog

Phenotypic characterization of a novel HO-1 depletion model in the rat

Although the protective role of HO-1 induction in various forms of kidney disease is well established, mechanisms other than heme catabolism to biliverdin, bilirubin and carbon monoxide have recently been identified. Unraveling these mechanisms requires the generation of appropriate animal models. The present study describes the generation of a HO-1 deficient Hmox1−/− rat model and characterizes its renal and extrarenal phenotype. Hmox1−/− rats had growth retardation and splenomegaly compared to their Hmox1+/+ littermates. Focal segmental glomerulosclerosis-type lesions and interstitial inflammatory infiltrates were prominent morphologic findings and were associated with increased blood urea nitrogen, serum creatinine and albuminuria. There was no increase in iron deposition in glomeruli, tubules or interstitium. Iron deposition in spleen and liver was reduced. Electron microscopic examination of glomeruli revealed edematous podocytes with scant areas of foot process effacement but otherwise well preserved processes and slit-diaphragms. Of the filtration barrier proteins examined, β-catenin expression was markedly reduced both in glomeruli and extrarenal tissues. Since the rat is the preferred laboratory animal in experimental physiology and pathophysiology, the rat model of HO-1 deficiency may provide a novel tool for investigation of the role of this enzyme in renal function and disease. © 2016, Springer International Publishing Switzerland

Constitutive control of AKT1 gene expression by JUNB/CJUN in ALK plus anaplastic large-cell lymphoma: a novel crosstalk mechanism

Anaplastic lymphoma kinase-positive (ALK+) anaplastic large-cell lymphoma (ALCL) is an aggressive T-cell non-Hodgkin lymphoma characterized by the t(2; 5), resulting in the overexpression of nucleophosmin (NPM)-ALK, which is known to activate the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, resulting in cell cycle and apoptosis deregulation. ALK+ ALCL is also characterized by strong activator protein-1 (AP-1) activity and overexpression of two AP-1 transcription factors, CJUN and JUNB. Here, we hypothesized that a biologic link between AP-1 and AKT kinase may exist, thus contributing to ALCL oncogenesis. We show that JUNB and CJUN bind directly to the AKT1 promoter, inducing AKT1 transcription in ALK+ ALCL. Knockdown of JUNB and CJUN in ALK+ ALCL cell lines downregulated AKT1 mRNA and promoter activity and was associated with lower AKT1 protein expression and activation. We provide evidence that this is a transcriptional control mechanism shared by other cell types even though it may operate in a way that is cell context-specific. In addition, STAT3 (signal transducer and activator of transcription 3)-induced control of AKT1 transcription was functional in ALK+ ALCL and blocking of STAT3 and AP-1 signaling synergistically affected cell proliferation and colony formation. Our findings uncover a novel transcriptional crosstalk mechanism that links AP-1 and AKT kinase, which coordinate uncontrolled cell proliferation and survival in ALK+ ALCL

Effect of Heme Oxygenase-1 Deficiency on Glomerular Proteomics

Background: The cytoprotective effect of heme oxygenase (HO)-1 in various forms of renal glomerular injury is established. However, little is known on the role of HO-1 in preserving glomerular structural/functional integrity in the absence of injury. The present study addressed this question in HO-1-deficient rats. Methods: HO-1-deficient rats were generated using zinc finger nuclease-mediated HO-1 gene ( Hmox1 ) disruption and studied. Glomeruli were isolated from HO-1-deficient ( Hmox1 -/- ) rats and their wild type (WT) littermates for proteomic analysis. Results: Glomerular lesions were characterized and differentially expressed proteins important for preserving integrity of the glomerular filtration barrier were identified. HO-1-deficient ( Hmox1 -/- ) rats developed albuminuria with decreased glomerular filtration rate. In albuminuric rats, there were lesions resembling focal and segmental glomerulosclerosis (FSGS). Western blot analysis of the integral slit diaphragm proteins, nephrin and podocin revealed a significant decrease in nephrin, with no change in podocin. Proteomic analysis of glomerular protein lysates from Hmox1 -/- and WT rats revealed differential expression of proteins previously linked with FSGS pathogenesis. Specifically, ?-actinin-4, actin related protein 3, cytokeratins and novel candidates including transgelin-2 and lamins. Bioinformatic analysis predicted the upregulation of pathways implicated in platelet aggregation and fibrin clot formation. Conclusion: HO-1 is a putative regulator of proteins important in preserving glomerular structural stability and integrity, and in minimizing the activity of proinflammatory pathways. © 2016 S. Karger AG, Basel

The therapeutic potential of p53 reactivation by nutlin-3a in ALK anaplastic large cell lymphoma with wild-type or mutated p53

p53 is expressed frequently, but is rarely mutated in anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) tumours. Nutlin-3a is a recently developed small molecule that targets Mdm2, a critical negative regulator of p53, and disrupts the p53-Mdm2 interaction resulting in p53 stabilization and activation. We show that nutlin-3a activates p53 in ALK ALCL cells carrying a wild type (wt) or mutated but partially functional p53 gene resulting in p53-dependent cell-cycle arrest and apoptosis. Cell-cycle arrest was associated with upregulation of the cyclin-dependent kinase inhibitor p21. Nutlin-3a-induced apoptotic cell death was accompanied by Bax and Puma upregulation, downregulation of Bcl-xl, survivin, and caspase-3 cleavage, and this was reduced when p53-dependent transactivation activity was inhibited by pifithrin-α, or when pifithrin-was used to inhibit direct p53 targeting of mitochondria. Nutlin-3a sensitized the activation of the extrinsic apoptotic pathway in wt-p53 ALK ALCL cells, in part, through upregulation of DR-5 and downregulation of c-Flip S/L, and was synergistic with TRAIL in cell death induction. In addition, nutlin-3a treatment enhanced doxorubicin cytotoxicity against ALK ALCL cells harbouring mt p53, and this was associated with p73 upregulation. These data suggest that disruption of the p53-mdm2 interaction by nutlin-3a offers a novel therapeutic approach for ALK ALCL patients. © 2009 Macmillan Publishers Limited All rights reserved

Expression patterns of endothelin-1 and its receptors in colorectal cancer

Background and Objectives Endothelin-1 (ET-1), a potent vasoconstricting peptide, plays an important role in carcinogenesis. Previous in vitro studies have shown that colorectal cancer cells produce ET-1. Methods: ET-1 and its receptors ET-A (ETAR) and ET-B (ETBR) were analyzed in colorectal cancer cell lines and tumors by Western blot and immunohistochemistry. Also, ET-1 levels were measured by ELISA in blood samples collected before and after tumor resection. Results: ET-1 was immunohistochemically expressed by tumor cells at a variable level in 39 cases tested. The adjacent normal mucosa was negative for ET-1 expression. Strong ETAR expression observed in the deeper infiltrating areas at the periphery of neoplastic tissue correlated significantly with tumor stage. ETBR levels were very low or undetectable. Western blot analysis in paired (normal, tumor) fresh-frozen samples of colorectal cancers and in four colon carcinoma cell lines confirmed these findings. In addition, lower levels of ET-1 in the peripheral circulation after the tumor resection were found by ELISA as compared to those observed before surgery. Conclusions: ET-1 and ETAR, but not ETBR, are expressed at a higher level in primary and cultured colon carcinoma cells as compared to normal colon mucosa cells. Further functional studies are needed to explore the role of ET-1/ETAR axis in colon carcinogenesis. J. Surg. Oncol. 2012; 105: 643-649. (C) 2011 Wiley Periodicals, Inc