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In previous studies, we described a “counter-immunosurveillance” mechanism initiated by tumor-activated, interleukin-13 (IL-13)–producing natural killer T cells that signal Gr-1+ cells to produce transforming growth factor-β1 (TGF-β1), a cytokine that suppresses the activity of tumor-inhibiting cytolytic CD8+ T cells. Here, we show that in two tumor models (the CT-26 metastatic colon cancer and the 15-12RM fibrosarcoma regressor models), this counter-surveillance mechanism requires the expression of a novel IL-13 receptor, IL-13Rα2, on Gr-1intermediate cells, because down-regulation of IL-13Rα2 expression or the activator protein-1 signal generated by the receptor via in vivo administration of specific small interfering RNA or decoy oligonucleotides leads to loss of TGF-β1 production. Furthermore, acting on prior studies showing that IL-13Rα2 expression is induced (in part) by tumor necrosis factor-α (TNF-α), we show that receptor expression and TGF-β1 production is inhibited by administration of a TNF-α–neutralizing substance, TNF-αR-Fc (etanercept). Taking advantage of this latter fact, we then show in the CT-26 model that counter-immunosurveillance can be inhibited, anti-CT-26–specific CD8+ cytolytic activity can be restored, and CT-26 metastatic tumor nodules can be greatly decreased by administration of TNF-αR-Fc. Corroborative data were obtained using the 15-12RM fibrosarcoma model. These studies point to the prevention of metastatic cancer with an available agent with already known clinically acceptable adverse effects and toxicity. [Cancer Res 2008;68(9):3467–75]

Pathological disorders of the liver were shown to be associated with an impairment of hepatic drug metabolism mediated in part by growth factors. Augmenter of liver regeneration (ALR) is a novel liver-specific hepatotrophic growth factor, whereas its action on cytochrome P450 (P450) metabolism is completely unknown. Application of ALR to primary human hepatocytes in vitro reduced P450 isoenzyme activities (1A2 and 2A6) in a dose-dependent manner. Time-course analysis revealed that the maximal inhibitory effect was reached after 24 to 72 h of exposure with 50 nM ALR. The reduction of basal activities upon ALR treatment was 35% for CYP1A2, 56% for CYP2A6, 18% for CYP2B6, and 45% for CYP2E1. Additionally, after induction of P450 with specific inducers, ALR revealed an inhibitory effect on the isoenzyme activities (CYP1A2, 41%; CYP2B6, 35%). Investigations of protein and mRNA expression of basal and induced CYP1A2 and CYP3A4 after ALR treatment by Western blotting and real-time reverse transcriptase-polymerase chain reaction, respectively, suggest a regulation on the transcriptional level. Furthermore, ALR treatment increased nuclear factor kB activity and reduced constitutive androstane receptor but not pregnane X receptor or aryl hydrocarbon receptor expression. In contrast, ALR revealed no effects on phase II reactions (glutathione/oxidized glutathione, UDP-glucuronyltransferase conjugation). Our results indicate that ALR, as a member of hepatotrophic factors, down-regulates basal and induced P450 in human liver and therefore cross-links growth signals to regulation of hepatic metabolism. These findings further imply a possible role of ALR in drug interactions during impaired hepatic function, whereas liver regeneration is triggered.

Donor lungs contain large amounts of passenger leukocytes which are transferred to the recipient by organ transplantation. In this study we have analysed the fate of these cells and have studied the population of donor leucocytes detectable in the blood circulation of ten lung transplanted patients during the first postoperative weeks. To this aim we have applied immunocytological as well as flow cytometric analyses using monoclonal antibodies against polymorphic HLA class I antigens that differed between donor and recipient as well as antibodies against cell differentiation markers. The results demonstrate that donor cells can be detected in the circulation of all lung transplanted patients but there is a considerable interindividual variability between 0.9% and 17.5% (mean 5.1%) on postoperative day 3. Cells were usually detectable for 2–4 weeks and had disappeared in all patients after 1 month. The circulating donor cells consisted exclusively of lymphocytes. T cells were the predominant population, most of which seemed to be CD45R0+, but B and NK (natural killer) cells were also present. Probably due to the small numbers of patients studied no correlation between clinical parameters and the extent of donor lymphocyte persistence; there were no clinical graft-versus-host reactions. The findings demonstrate the regular existence of a transient (macro)chimerism due to passenger lymphocytes in the early phase after lung transplantation. The immunological function and the relation between this phenomenon and the long-term microchimerism which frequently develops after solid organ transplantation remain unclear.

Activation of receptor tyrosine kinases, such as fibroblast growth factor receptor (FGFR), platelet-derived growth factor receptor (PDGFR), and VEGF receptor (VEGFR), has been implicated in tumor progression and metastasis in human pancreatic cancer. In this study, we investigated the effects of TKI258, a tyrosine kinase inhibitor to FGFR, PDGFR, and VEGFR on pancreatic cancer cell lines (HPAF-II, BxPC-3, MiaPaCa2, and L3.6pl), endothelial cells, and vascular smooth muscle cells (VSMC). Results showed that treatment with TKI258 impaired activation of signaling intermediates in pancreatic cancer cells, endothelial cells, and VSMCs, even upon stimulation with FGF-1, FGF-2, VEGF-A, and PDGF-B. Furthermore, blockade of FGFR/PDGFR/VEGFR reduced survivin expression and improved activity of gemcitabine in MiaPaCa2 pancreatic cancer cells. In addition, motility of cancer cells, endothelial cells, and VSMCs was reduced upon treatment with TKI258. In vivo, therapy with TKI258 led to dose-dependent inhibition of subcutaneous (HPAF-II) and orthotopic (L3.6pl) tumor growth. Immunohistochemical analysis revealed effects on tumor cell proliferation [bromodeoxyuridine (BrdUrd)] and tumor vascularization (CD31). Moreover, lymph node metastases were significantly reduced in the orthotopic tumor model when treatment was initiated early with TKI258 (30 mg/kg/d). In established tumors, TKI258 (30 mg/kg/d) led to significant growth delay and improved survival in subcutaneous and orthotopic models, respectively. These data provide evidence that targeting FGFR/PDFGR/VEGFR with TKI258 may be effective in human pancreatic cancer and warrants further clinical evaluation. Mol Cancer Ther; 10(11); 2157–67. ©2011 AACR.

Patients with prolonged ulcerative colitis (UC) frequently develop colorectal adenocarcinoma for reasons that are not fully clear. To analyze inflammation-associated colonic tumorigenesis, we developed a chronic form of oxazolone-induced colitis in mice that, similar to UC, was distinguished by the presence of IL-13-producing NKT cells. In this model, the induction of tumors using azoxymethane was accompanied by the coappearance of F4/80+CD11b(high)Gr1(low) M2 macrophages, cells that undergo polarization by IL-13 and are absent in tumors that lack high level IL-13 production. Importantly, this subset of macrophages was a source of tumor-promoting factors, including IL-6. Similar to dextran sodium sulfate-induced colitis, F4/80+CD11b(high)Gr1(intermediate) macrophages were present in the mouse model of chronic oxazolone-induced colitis and may influence tumor development through production of TGF-β1, a cytokine that inhibits tumor immunosurveillance. Finally, while robust chronic oxazolone-induced colitis developed in myeloid differentiation primary response gene 88-deficient (Myd88-/-) mice, these mice did not support tumor development. The inhibition of tumor development in Myd88-/- mice correlated with cessation of IL-6 and TGF-β1 production by M2 and F4/80+CD11b(high)Gr1(intermediate) macrophages, respectively, and was reversed by exogenous IL-6. These data show that an UC-like inflammation may facilitate tumor development by providing a milieu favoring development of MyD88-dependent tumor-supporting macrophages.

Background: Successful liver gene therapy depends on efficient gene transfer techniques and long-lasting gene expression after successful transfer. Over the last decades important progress has been made with the introduction of viral vectors using animal models, but their use is hampered by a complex and costly preparation when compared to the simple and cost-effective preparation of plasmid DNA. These problems become even more critical when considering application of viral vectors in human gene therapy and gene therapy trials. In a recent report we were able to show that the hydrodynamics-based gene transfer of plasmid-DNA, containing the adeno-associated-virus specific inverted terminal repeats (AAV-ITR), prolong gene expression in the liver, but it remained unclear if plasmid gene transfer could achieve similar expression levels compared to viral-vector gene transfer. Methods: Rat livers were transfected in-vivo with AAV-ITR-containing plasmid-DNA using a modified hydrodynamics-based procedure. Expression levels were monitored thereafter and compared with expression levels after viral-vector gene transfer. Results: A high and stable long-term expression was achieved after in vivo transfection of rat livers with AAV-ITR-containing plasmids. The expression course resembled that after AAV-mediated gene transfer, and expression was at least as high, and lasted as long, as with rAAV-mediated gene transfer. Conclusion: We consider AAV-ITR-containing plasmids as a simple and cost-effective alternative to recombinant viral vectors, especially for liver-directed gene therapy in rodents. With ongoing progress in gene transfer methods for naked DNA, these plasmids may also become a successful alternative to recombinant viral vectors in human gene therapy.

Liver regeneration is a multistep and well-orchestrated process which is initiated by injuries such as tissue loss, infectious or toxic insults. Augmenter of liver regeneration (ALR) is a hepatotrophic growth factor which has been shown to stimulate hepatic regeneration after partial hepatectomy and therefore seems to be regulated during the regenerative process in the liver. Our aim was to analyze how ALR is regulated in hepatic tissues and which transcription factors might regulate its tissue-specific expression. Promoter studies of ALR (−733/+527 bp) revealed potential regulatory elements for various transcription factors like Foxa2, IL-6 RE-BP and C/EBPβ. Analysis of the promoter activity by performing luciferase assays revealed that co-transfection with Foxa2 significantly induced the activity of ALR promoter in HepG2 cells. EMSA and Supershift analysis using anti-Foxa2 antibody confirmed the specific binding of Foxa2 to ALR promoter and this binding was inducible when the cells were simultaneously stimulated with IL-6. The increased binding after activation with IL-6 and/or Foxa2 was confirmed by elevated ALR protein levels using Western blot technique. In addition, we could not detect any binding of C/EBPβ and IL-6 RE-BP to the promoter of ALR. In conclusion, these results indicate that ALR is regulated by Foxa2, and this regulation may be amplified by IL-6.

The murine monoclonal antibody BMA 031 (IgG2b) is directed to a monomorphic epitope on the human alpha/beta T-cell receptor. In contrast to anti-CD3 antibodies of the IgG2b isotype, BMA 031 is able to induce a proliferative response in T-cells from IgG2b low responders. This response occurs independently of cross-linking conditions indicating that the mode of activation differs from stimulation by the anti-CD3 antibody OKT3 (IgG2a) which strictly depends on cross-linking conditions. to further characterize the stimulatory potential of the two antibodies we studied the lymphocyte subsets responsive to stimulation by BMA 031 and OKT3. In CD45RA+ cells both antibodies exhibited similar effects. They induced weak expression of the 55-kDa chain of the interleukin-2 receptor (CD25), virtually no interleukin-2 secretion, but nevertheless strong proliferation. In CD45R0+ cells OKT3 and BMA 031 showed markedly different effects. OKT3 stimulated strong CD25 expression, strong interleukin-2 production, and marked proliferation. In contrast, CD45R0+ cells stimulated by BMA 031 showed only weak CD25 expression but neither interleukin-2 production nor proliferation. These data suggest that CD45RA+ and CD45R0+ cells differ in their capability to produce interleukin-2 upon stimulation via the CD3/T-cell receptor complex and also in the requirement for interleukin-2 to mount a proliferative response. The differential effect of OKT3 and BMA 031 in CD45R0+ cells probably results from the failure of BMA 031 to trigger interleukin-2 production which may be a consequence of its inability to induce CD3/T-cell receptor cross-linking in IgG2b low responders BMA 031 is therefore a useful tool for the selective activation of CD45RA+ cells in these individuals.

Monoclonal antibodies (mAb) against the CD3/T cell receptor (TcR) complex were analyzed for their ability to activate human thymocytes. In addition to mAb detecting epitopes on the CD3 complex (OKT3, BMA 030) the activation potential of recently developed mAb against common epitopes on the alpha/beta T-cell receptor (anti-TcR mAb: BMA 031, BMA 032) was evaluated. Several differences were observed between the two types of mAb: (a) Binding of the tested anti-CD3 mAb to thymocytes resulted in a rapid increase in the level of cytoplasmic free calcium ions [Ca2+]i, whereas no significant changes in [Ca2+]i were detected in thymocytes stimulated with BMA 031 or BMA 032. (b) Induction of effective proliferation induced by mAb OKT3 depended on exogenous IL-2 and in addition on the presence of accessory cells or phorbol-ester. Proliferation induced by BMA 031 only required exogenous IL-2. (c) OKT3 but not BMA 031 inhibited proliferation of thymocytes induced via the CD2 molecule. These studies indicate that anti-CD3 and anti-TcR mAb transduce different signals in thymocytes. Since the two types of mAb are directed to the same molecular complex the observed differences also support the idea that there are functionally different compartments in the CD3/TcR complex which may activate different signaling pathways.

BMA031 is an IgG2b antibody directed towards the human alpha/beta T-cell receptor that is able to induce proliferation of peripheral blood mononuclear cells independent of antibody crosslinking. The proliferative response to BMA031 during the first 3 days of culture is usually of similar magnitude to that induced by the IgG2a CD3 antibody OKT3 but decreases quickly afterwards. Stimulation by BMA031 induces no measurable IL-2 release, very low expression of the IL-2 receptor, and does not trigger cytotoxic effector function. However, cross-linking of the antibody or addition of IL-2 leads to enhanced and prolonged proliferation, strong IL-2 receptor expression, and cytotoxic activity, features that are usually found after stimulation by the IgG2a CD3 antibody OKT3 in soluble form. The stimulatory effect of BMA031 cannot be diminished by IL-2 receptor blocking, whereas stimulation by OKT3 is strongly reduced. Moreover, proliferation induced by BMA031 has lower sensitivity to inhibition by ciclosporin than OKT3. From these results two major conclusions can be drawn: (1) an IL-2-independent way of activation may be important for the short-term proliferation of the T cells stimulated by BMA031 and (2) after stimulation by BMA031, cells reach a state of activation that is different from that induced by OKT3. These differences are most likely related to the different specificities of the antibodies, alpha/beta TcR versus CD3, suggesting that different activation signals are triggered via CD3 and via the alpha/beta TcR.

Rare cases of graft-versus-host disease after liver transplantation indicate that donor lymphocytes may be transferred to the recipient by human liver grafts. In this study, we have analyzed the number and subpopulations of donor lymphocytes transferred by liver grafts in order to evaluate the potential relevance of these cells after transplantation. Therefore, mononuclear cells were isolated from the tissue of perfused human donor livers and from the associated lymph nodes. The number of lymphocytes, their location, and surface marker expression were determined by immunostaining. The majority of lymphocytes transferred by the grafts were found within the liver tissue (5.3 +/- 2.9 x 10(9) cells). These lymphocytes are mainly T and NK cells, predominantly CD8+, are partially activated (28% HLA-DR+), and show strong adhesion molecule expression (88% LFA-1(3+)). In addition, 20-500 x 10(6) of resting lymphocytes, predominantly T and B cells, are transmitted by lymph nodes. These findings demonstrate that considerable numbers of donor lymphocytes of distinct phenotype are regularly transmitted to the recipient by human liver grafts and may be of functional relevance after transplantation.

To establish a suitable control for pancreatic tumor cell lines, we have isolated and cultured primary human pancreatic duct cells from transplant donors. Duct cells were isolated by dissecting the main pancreatic duct and first-degree branches and enzymatic digestion. Aggregates of cells were cultured for 1 up to 5 weeks and monitored for changes in morphology and growth by phase contrast microscopy. Contaminating fibroblasts were mechanically removed from day 4 on and by cloning of epithelial cells. Cultured cells were characterized by phase contrast microscopy, electron microscopy, and immunofluorescence with antibodies against intermediate filaments (cytokeratins, vimentin, desmin), mucins (Du-Pan-2, CA 19-9), carbonic anhydrase II, acinar cell enzymes (amylase, lipase, trypsin), and islet cells. About 90% of the cultured cells could be identified as ductal epithelial cells by their expression of cytokeratins, mucins, and carbonic anhydrase II. These cells showed the ultrastructural features of duct cells. After 3-5 weeks of culture, most of the cultured cells showed co-expression of cytokeratins and vimentin in addition to duct cell markers. About 10% of cells were contaminating fibroblasts (vimentin positive, cytokeratin negative). The cultured normal human duct cells as the postulated cells of origin of the pancreatic adenocarcinoma may serve as a useful control for cultured pancreatic tumor cell lines.

Mouse IgG2a and IgG3 antibodies directed to the human T-cell receptor/CD3 complex stimulate peripheral blood mononuclear cells in almost all individuals. By contrast, responder and non-responder individuals exist for the stimulatory effect of mouse IgG1 and IgG2b antibodies. Whereas responsiveness to IgG1 antibodies is rather frequent (60-70%) and is known to be determined by an Fc gamma RII polymorphism on the accessory cells, little is known about the underlying factors of the rare (6%) IgG2b responsiveness. In this study it is shown that (1) IgG2b responsiveness is genetically determined with a dominant pattern of inheritance; (2) IgG2b responsiveness is determined by a radioresistant feature of responder accessory cells which can be substituted by artificial cross-linking, but not by IL-1 beta or IL-2; (3) stimulation of peripheral blood mononuclear cells of an IgG2b responder by IgG2b antibodies requires rather high antibody concentration compared with stimulation by IgG2a antibodies; (4) the stimulation leads to proliferation and IL-2 receptor expression, but no measurable IL-2 production; (5) antibody binding to known Fc gamma receptors (Fc gamma RI, Fc gamma RII, Fc gamma RIII) is not involved in the stimulatory effect of the IgG2b antibodies in responders. These results demonstrate that responsiveness to IgG2b antibodies against the TcR/CD3 complex depends on a genetically determined feature of accessory cells that is not identical with any of the known Fc gamma receptors. Most likely, the stimulatory effect observed in IgG2b responders is explained by a low grade cross-linking of the antibody by a not yet identified polymorphic structure on the surface of accessory cells.

Ciclosporin, an immunosuppressant, is metabolized by the liver cytochrome P450 system. Changes in the pattern of its metabolites in blood and urine in patients with disturbed liver function have been studied. Forty seven kidney graft patients receiving 2.9 mg/kg/d ciclosporin b.i.d., and no additional medication that would interfere with ciclosporin metabolism, were allocated to three groups according to liver function: I with normal liver function (n = 19), II with elevated liver enzyme activity or bilirubin concentration in serum (n = 20), and III with cholestasis (n = 8). Ciclosporin and 17 metabolites were determined in blood and 24 h-urine. In blood the trough concentrations of metabolites M19 and M1A were significantly higher in group III than in groups I and II. The total quantity of metabolites excreted in 24 h-urine was significantly different for H230, M4N69 and M1A (group III greater than I = II). Renal excretion of the daily dose of ciclosporin in patients in group I was 2.7%, group II 3% and group III 5.7%. In group III compared to group I the ciclosporin metabolite pattern was shifted to a relatively higher concentration of M19 in blood and of H 230, M19 and M1A in urine. Since high ciclosporin metabolite concentrations appear to be associated with nephrotoxicity, the metabolite pattern in patients with impaired liver function should be monitored.

Background & Aims Previous studies have shown that fibrosis developing in chronic experimental colitis is driven by interleukin (IL)-13 signaling via IL-13Rα 2 and the production of transforming growth factor (TGF)-β1. In the present study, we sought to determine the fibrogenic downstream events set in motion by such signaling. Methods Experimental colitis with late-onset intestinal fibrosis was induced by weekly intrarectal administration of trinitrobenzene sulfonic acid (TNBS) to BALB/c mice. Blockade of IL-13 signaling via IL-13Rα 2 and TGF-β1 signaling was achieved by the administration of small interfering RNA or decoy oligonucleotides that target promoter sequences of signaling components of these receptors. Effects of blockade were determined by enzyme-linked immunosorbent assay or Western blotting detecting specific key fibrogenic factors and by measurement of collagen production. Results Initially, we showed that abrogation of IL-13 activity via blockade of IL-13Rα 2 and TGF-β1 signaling results in severe inhibition of expression of colonic insulin-like growth factor (IGF)-I and early growth response gene (Egr)-1, factors known to initiate and sustain fibrosis. We then showed that Egr-1 was necessary early in the fibrotic process for caspase-mediated apoptosis of myofibroblasts and the production of urokinase plasminogen activator, a protein that enhances TGF-β1 activation. Finally, we showed that IGF-I (together with TGF-β1) acts later in the process to stimulate myofibroblasts to deposit collagen in the colon. Conclusions These studies establish that IL-13 signaling via the IL-13Rα 2 is a key initiation point for a complex fibrotic program in the colon consisting of TGF-β1 activation, IGF-I and Egr-1 expression, myofibroblast apoptosis, and myofibroblast production of collagen.

Heat stress (HS) reduces the many sequelae of lipopolysaccharide (LPS)-induced endotoxemia. Without HS, endotoxins have been shown to induce a transcriptional down-regulation of hepatocyte transport proteins for bile acids and organic anions. We performed experiments in isolated perfused rat livers at various times after LPS administration with and without HS pretreatment to determine whether HS would correct deficient transport of bromosulfophthalein (BSP). Possible mechanisms involved were investigated in livers from intact animals. In isolated perfused livers, LPS injection reduced BSP excretion to 48% compared with saline-injected controls (P < 0.01). When HS was applied 2 hours prior to LPS, BSP excretion increased to 74% of controls (P < 0.05 vs LPS and controls). Expression of the basolateral (Oatp1a1) and canalicular (Mrp2) organic anion transporter involved in the transport of BSP recovered more rapidly when HS preceded LPS application. Recovery of mRNA levels of these transporters occurred also earlier. Coimmunoprecipitation experiments and immunoelectron microscopy using a double immunogold labeling of heat shock protein 70 (HSP70) and various hepatocyte transporters suggested colocalization with HSP70 for the canalicular bile acid transporter (Bsep) in the subcanalicular space. In contrast, no colocalization was shown for Ntcp and anion transporters. In conclusion, we could show that HS enhances recovery of organic anion transporters and bile acid transporters following endotoxemia. Faster recovery of mRNA seems to be a key mechanism for anion transporters, whereas physical interaction with HSP70 plays a role in preservation of bile acid transporters. This interaction of HSP70 and canalicular transporters occurs only in pericanalicular vesicles but not when the protein is integrated into the plasma membrane.

The mouse monoclonal antibody (mAb) BMA031 (IgG2b) has recently been described to be directed against a monomorphic part of the human T cell receptor (TcR) alpha/beta. In vitro analysis of its stimulatory potential for mononuclear cells revealed two patterns of responsiveness. Out of 35 tested individuals only 2 generated a proliferative response to low antibody concentrations (15 ng/ml; "high responders"), the others ("low responders") responded only to high antibody concentrations (1.5 micrograms/ml); the anti-CD3 mAb UCHT1 (IgG2b) stimulated only the two high responders. This response pattern to BMA031 was determined by the accessory cell compartment in the culture. Stimulation by BMA031 in low responders demonstrated some unusual features: (a) high antibody concentrations were required, (b) addition of autologous serum had no inhibitory effect and (c) vigorous depletion of macrophages reduced but did not abolish the proliferative response. These characteristics were shared by two other mAb, BMA032 and BW239/347, presumably directed against the TcR alpha/beta but not by several other antibodies to the TcR/CD3 complex. Thus, the results demonstrate unusual stimulatory properties of three anti-TcR alpha/beta mAb, inducing a proliferative response without antibody cross-linking. This suggests that the stimulatory effect of anti-TcR/CD3 complex mAb is not only determined by their isotype, but also strongly depends on their epitope specificity.