The role of platelets and von Willebrand factor in the procoagulant phenotype of inflammatory bowel disease

OBJECTIVE

Although the risk for thrombosis is well documented for inflammatory bowel disease (IBD) patients, the underlying pathological mechanism seems to be different from other thrombotic conditions. Deciphering the actors responsible for the increased risk of thrombosis in IBD would help to improve management of this frequent complication.

DESIGN

We studied the interplay between platelets, coagulation, and von Willebrand factor (VWF) in 193 IBD patients and in experimental models (acute and chronic) of colitis in wild-type and VWF-deficient mice.

RESULTS

We found a platelet-dependent increase in thrombin generation in IBD patients and in our mouse model of colitis. Agglutinated platelets were present in the blood of patients and mice. Interestingly, we observed not only a significant increase in total VWF antigen, but we were able to detect the presence of active VWF (VWF in its platelet-binding conformation; 3.2±2.7µg/ml) in the plasma of 30% of all IBD patients. In healthy controls, active VWF levels were below 0.3µg/ml. This led us to further explore experimental colitis in VWF-deficient mice and we observed that these mice were protected against the procoagulant state triggered by the colitis. Unexpectedly, these mice also manifested a significant worsening of colitis severity both in acute and chronic models.

CONCLUSION

Platelets and VWF (including its active form) appear to be central players in the procoagulant phenotype in IBD. We observed that the role of VWF in hemostasis differs from its role in colic tissue healing, potentially opening new therapeutic avenues for a life-threatening complication in IBD patients.

Transcriptomic Study on Human Skin Samples: Identification of Two Subclasses of Actinic Keratoses

Actinic keratoses (AKs) are sun-damaged skin areas that affect 20% of the European adult population and more than 50% of people aged 70 years and over. There are currently no clinical or histological features allowing us to identify to which clinical class (i.e., regression or progression) an AK belongs. A transcriptomic approach seems to be a robust tool for AK characterization, but there is a need for additional studies, including more patients and elucidating the molecular signature of an AK. In this context, the present study, including the largest number of patients to date, is the first aiming at identifying biological features to objectively distinguish different AK signatures. We highlight two distinct molecular profiles: AKs featuring a molecular profile similar to squamous cell carcinomas (SCCs), which are called "lesional AKs" (AK_Ls), and AKs featuring a molecular profile similar to normal skin tissue, which are called "non-lesional AKs" (AK_NLs). The molecular profiles of both AK subclasses were studied, and 316 differentially expressed genes (DEGs) were identified between the two classes. The 103 upregulated genes in AK_L were related to the inflammatory response. Interestingly, downregulated genes were associated with keratinization. Finally, based on a connectivity map approach, our data highlight that the VEGF pathway could be a promising therapeutic target for high-risk lesions.

The VWF/LRP4/αVβ3-axis represents a novel pathway regulating proliferation of human vascular smooth muscle cells

AIMS

Von Willebrand factor (VWF) is a plasma glycoprotein involved in primary haemostasis, while also having additional roles beyond haemostasis namely in cancer, inflammation, angiogenesis, and potentially in vascular smooth muscle cell (VSMC) proliferation. Here, we addressed how VWF modulates VSMC proliferation and investigated the underlying molecular pathways and the in vivo pathophysiological relevance.

METHODS AND RESULTS

VWF induced proliferation of human aortic VSMCs and also promoted VSMC migration. Treatment of cells with a siRNA against αv integrin or the RGT-peptide blocking αvβ3 signalling abolished proliferation. However, VWF did not bind to αvβ3 on VSMCs through its RGD-motif. Rather, we identified the VWF A2 domain as the region mediating binding to the cells. We hypothesized the involvement of a member of the LDL-related receptor protein (LRP) family due to their known ability to act as co-receptors. Using the universal LRP-inhibitor receptor-associated protein, we confirmed LRP-mediated VSMC proliferation. siRNA experiments and confocal fluorescence microscopy identified LRP4 as the VWF-counterreceptor on VSMCs. Also co-localization between αvβ3 and LRP4 was observed via proximity ligation analysis and immuno-precipitation experiments. The pathophysiological relevance of our data was supported by VWF-deficient mice having significantly reduced hyperplasia in carotid artery ligation and artery femoral denudation models. In wild-type mice, infiltration of VWF in intimal regions enriched in proliferating VSMCs was found. Interestingly, also analysis of human atherosclerotic lesions showed abundant VWF accumulation in VSMC-proliferating rich intimal areas.

CONCLUSION

VWF mediates VSMC proliferation through a mechanism involving A2 domain binding to the LRP4 receptor and integrin αvβ3 signalling. Our findings provide new insights into the mechanisms that drive physiological repair and pathological hyperplasia of the arterial vessel wall. In addition, the VWF/LRP4-axis may represent a novel therapeutic target to modulate VSMC proliferation.

Proton MR Spectroscopy and Diffusion MR Imaging Monitoring to Predict Tumor Response to Interstitial Photodynamic Therapy for Glioblastoma

Despite recent progress in conventional therapeutic approaches, the vast majority of glioblastoma recur locally, indicating that a more aggressive local therapy is required. Interstitial photodynamic therapy (iPDT) appears as a very promising and complementary approach to conventional therapies. However, an optimal fractionation scheme for iPDT remains the indispensable requirement. To achieve that major goal, we suggested following iPDT tumor response by a non-invasive imaging monitoring. Nude rats bearing intracranial glioblastoma U87MG xenografts were treated by iPDT, just after intravenous injection of AGuIX® nanoparticles, encapsulating PDT and imaging agents. Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) allowed us an original longitudinal follow-up of post-treatment effects to discriminate early predictive markers. We successfully used conventional MRI, T2 star (T2*), Diffusion Weighted Imaging (DWI) and MRS to extract relevant profiles on tissue cytoarchitectural alterations, local vascular disruption and metabolic information on brain tumor biology, achieving earlier assessment of tumor response. From one day post-iPDT, DWI and MRS allowed us to identify promising markers such as the Apparent Diffusion Coefficient (ADC) values, lipids, choline and myoInositol levels that led us to distinguish iPDT responders from non-responders. All these responses give us warning signs well before the tumor escapes and that the growth would be appreciated.

A new algorithm for a better characterization and timing of the anti-VEGF vascular effect named "normalization"

Antiangiogenics are widely used in cancer treatment in combination with chemotherapy and radiotherapy for their vascular effects. Antiangiogenics are supposed to induce morphological and functional changes in the chaotic tumor vasculature that would help enhance the therapeutic efficacy of chemotherapy and radiotherapy through the amelioration of the drug delivery or the oxygenation in the tumor, respectively. However, finding the best treatment sequence is not an easy task to achieve and no consensus has yet been established because of the lack of knowledge regarding when and for how long the vascular network is ameliorated. The aim of this work was to develop a dedicated image processing algorithm able to analyze the vascular structures on optical microscopy images of the vascular network and to follow its fine modifications in vivo, over time. We applied this algorithm to follow the evolution of the vascular parameters (vascularized tissue surface, branches, sprouts and length), in response or not to anti-VEGF therapy (10 mg/kg/day) and determine precisely whether there is really a vascular "normalization" with anti-VEGF therapy in comparison with the parameters extracted from healthy vascular networks. We found that for this determination, the choice of region of interest to analyze is critical as it is important to compare only microcirculation areas and avoid areas with arteriole-venule-capillary hierarchy. The algorithm analysis allowed us to define a vascular "normalization" in treated tumors, between 8 and 12 days of bevacizumab treatment that was confirmed by standard immunohistochemical analysis, microvascular permeability assessment and immunohistological blood perfusion assessment.

Molluscum contagiosum surrounded by a white halo and Sezary syndrome

BACKGROUND

Molluscum contagiosum (MC) is caused by a DNA virus of the poxvirus group. It is common in children, and is also found in sexually active adults and HIV-seropositive patients. Cellular immunity is essential to controlling MC virus infection. We report the first observation of a patient with stage IV Sezary syndrome, who presented multiple molluscum contagiosum, spread and surrounded by a pale halo.

CASE REPORT

A woman aged 70 presented with aggravation of Sezary syndrome diagnosed in 2009 and treated with topical corticosteroids. The examination showed a generalized pruritic exanthem and multiple flesh-coloured papules from 1 to 3 mm, spread over the entire skin surface and surrounded by a white halo. Histological examination of a lesion showed the presence of infected cells with intracytoplasmic inclusions infected in an acanthotic epidermis, surrounded by a melaninopenic hypomelanosis with a normal melanocyte density. There was no inflammatory character. The diagnosis of multiple molluscum contagiosum was given, the application of clobetasol propionate was suspended and treatment with chlorambucil 4 mg/day and prednisone 0.5 mg/kg/day was started. The evolution of the rash and pruritus was rapidly favourable. After 3 months, the rash and pruritus had regressed. There was no molluscum contagiosum or clear halo.

CONCLUSION

We report the original observation of a patient with stage IV Sezary syndrome, who presented multiple molluscum contagiosum, spread and surrounded by a pale halo, without inflammation, eczema or disappearance of melanocytes. This halo could be due to the secretion of a protein by molluscum contagiosum inhibiting inflammation around this MC. To our knowledge, this phenomenon reported in a patient with severe atopic dermatitis associated with Sezary syndrome has not previously been described.

Synergistic antitumor effect between gefitinib and fractionated irradiation in anaplastic oligodendrogliomas cannot be predicted by the Egfr signaling activity

In high-grade gliomas, the identification of patients that could benefit from EGFR inhibitors remains a challenge, hindering the use of these agents. Using xenografts models, we evaluated the antitumor effect of the combined treatment "gefitinib + radiotherapy" and aimed to identify the profile of responsive tumors. Expression of phosphorylated proteins involved in the EGFR-dependent signaling pathways was analyzed in 10 glioma models. We focused on three models of anaplastic oligodendrogliomas (TCG2, TCG3 and TCG4) harboring high levels of phospho-EGFR, phospho-AKT and phospho-MEK1. They were treated with gefitinib (GEF 75 mg/kg/day x 5 days/week, for 2 weeks) and/or fractionated radiotherapy (RT: 5x2Gy/week for 2 weeks). Our results showed that GEF and/or RT induced significant tumor growth delays. However, only the TCG3 xenografts were highly responsive to the combination GEF+RT, with ∼50% of tumor cure. Phosphoproteins analysis five days after treatment onset demonstrated in TCG3 xenografts, but not in TCG2 model, that the EGFR-dependent pathways were inhibited after GEF treatment. Moreover, TCG3-bearing mice receiving GEF monotherapy exhibited a transient beneficial therapeutic response, rapidly followed by tumor regrowth, along with a major vascular remodeling. Taken together, our data evoked an "EGFR-addictive" behavior for TCG3 tumors. This study confirms that combination of gefitinib with fractionated irradiation could be a potent therapeutic strategy for anaplastic oligodendrogliomas harboring EGFR abnormalities but this treatment seems mainly beneficial for "EGFR-addictive" tumors. Unfortunately, neither the usual molecular markers (EGFR amplification, PTEN loss) nor the basal overexpression of phosphoproteins were useful to distinguish this responsive tumor. Evaluating the impact of TKIs on the EGFR-dependent pathways during the treatment might be more relevant, and requires further validation.

FVIIIra, CD15, and tryptase performance in the diagnosis of skin stab wound vitality in forensic pathology

The timing of skin wounds is one of the most challenging problems in forensic pathology. In the first minutes or hours after infliction, histological examination fails to determine whether a wound was sustained before or after death. The aim of this study was to evaluate the use of three immunohistochemical markers (FVIIIra, CD15, and tryptase) for the interpretation of the timing of cutaneous stab wounds. We evaluated these markers in intravital wounds from autopsy cases (n = 12) and surgical specimens (n = 58). As controls, we used normal skin samples from autopsies (n = 8) and an original ex vivo surgical human model of recent postmortem wounds (n = 24). We found overexpression of FVIIIra in 100 % of vital wounds, but also in 53 % of the controls. The number of CD15-positive cells was higher in wound margins than in internal controls (p < 0.0001) and was significantly correlated with the time interval between incision and devascularization (p = 0.0005; minimal time for positivity, 9 min). Using the anti-tryptase antibody, we found that the mast cell degranulation rate was higher in wound margins (p < 0.0001) and correlated with the time interval (minimal time, 1 min). The sensitivity and specificity for the diagnosis of vitality were respectively 100 and 47 % for FVIIIra, 47 and 100 % for CD15, and 60 and 100 % for tryptase. The inter-observer agreement coefficients were 0.68 for FVIIIra, 0.90 for CD15, and 0.46 for tryptase. Finally, we demonstrated that these markers were not reliable in putrefied or desiccated specimens. In conclusion, CD15 and tryptase, but not FVIIIra, may be useful markers for differentiating recent antemortem from postmortem injuries.

Visualisation of sentinel lymph node with indium-based near infrared emitting Quantum Dots in a murine metastatic breast cancer model

Due to its non-invasiveness, high temporal resolution and lower cost, fluorescence imaging is an interesting alternative to the current method (blue dye and radiocolloid) of sentinel lymph node (SLN) mapping in breast cancer. Near-infrared (NIR) emitting cadmium-based Quantum Dots (QDs) could be used for this purpose; however, their wide application is limited because of the toxicity of heavy metals composing the core. Our recent work demonstrated that indium-based QDs exhibit a weak acute local toxicity in vivo compared to their cadmium-based counterparts. In the present study we confirmed the weak toxicity of CuInS(2)/ZnS QDs in different in vitro models. Further in vivo studies in healthy mice showed that In-based QDs could be visualised in SLN in a few minutes after administration with a progressive increase in fluorescence until 8 h. The quantity of indium was assessed in selected organs and tissues by inductively coupled plasma - mass spectroscopy (ICP-MS) as a function of post-injection time. QD levels decrease rapidly at the injection point in the first hours after administration with a parallel increase in the lymph nodes and to a lesser extent in the liver and spleen. In addition, we observed that 3.5% of the injected indium dose was excreted in faeces in the first 4 days, with only trace quantities in the urine. Metastatic spread to the lymph nodes may hamper its visualisation. Therefore, we further performed non-invasive fluorescence measurement of QDs in SLN in tumour-bearing mice. Metastatic status was assessed by immunohistology and molecular techniques and revealed the utmost metastatic invasion of 36% of SLN. Fluorescence signal was the same irrespective of SLN status. Thus, near-infrared emitting cadmium-free QDs could be an excellent SLN tracer.

Reactive nodular fibrous pseudotumor: a first report of gastric localization and clinicopathologic review

Reactive nodular fibrous pseudotumor (RNFP) of the gastrointestinal tract is a distinct benign lesion, which could originate from a reactive proliferation of multipotential subserosal cells. This is the first case to be reported in the stomach. It was fortuitously discovered in a 60-year-old man with history of bulbar ulcer and gastritis. Gross examination revealed three lesions in the gastric wall and an adjacent lesion in the lesser omentum. Histologically, lesions were composed of a proliferation of spindle and stellate cells in a dense collagenic hyalinized background containing a mononuclear cell inflammatory infiltrate with numerous lymphoid aggregates and plasma cells with perivascular disposition. Immunohistochemistry showed staining for cytokeratins (AE1/AE3), vimentin and smooth muscle actin, without staining for the neurofilament and S100 proteins, synaptophysin, calretinin, CD117 (c-kit), CD34, desmin, caldesmon or anaplastic lymphoma kinase (ALK-1). Complete excision was performed, and no evidence of disease was found 4 months later. After analysing clinical, morphological and immunohistochemical features of this entity, the main differential diagnoses will be discussed, including calcifying fibrous pseudotumor, which shares morphological characteristics with RNFP, but which immunohistochemistry and the ultrastructural study suggest that it may be a result of another reactive process.

[Glyoxal: a possible polyvalent substitute for formaldehyde in pathology?]

The quest for formaldehyde substitutes is motivated by two fundamental developments: the OSHA regulation standard declaring it hazardous and advocating its substitution with less dangerous chemicals and the fact that formalin is a poor preserver of nucleic acids. Among the non-alcoholic formalin substitute, glyoxal has been hailed as the best alternative. In this work, we showed that glyoxal-containing fixatives are not plausible polyvalent substitution options.

Increased expression of matrilin-3 not only in osteoarthritic articular cartilage but also in cartilage-forming tumors, and down-regulation of SOX9 via epidermal growth factor domain 1-dependent signaling

OBJECTIVE

To identify regulators of the cartilaginous phenotype, on the basis of their differential expression in human conventional chondrogenic tumors compared with articular cartilage.

METHODS

Differential proteomics analysis revealed matrilin-3 (MATN3) as a candidate regulator of the cartilaginous phenotype. Its capacity to modulate gene expression was investigated in human HCS-2/8 chondrosarcoma cells and transfected chondrocytes, using cell culture fractionation, reverse transcription-polymerase chain reaction, and Western blot analyses.

RESULTS

Increased expression of the cartilage-specific matrix protein MATN3 was specifically observed in enchondromas and conventional chondrosarcomas. A substantial fraction of MATN3 was found in cytoplasmic structures of tumor cells, as demonstrated by immunohistochemistry. Analyses of intracellular MATN3 revealed that it corresponded to an imperfectly maturated MATN3 polypeptide, both in HCS-2/8 human chondrosarcoma cells and in transfected human chondrocytes. Moderately increased expression of MATN3 resulted in its intracellular retention. Antibody-mediated blockade of soluble, extracellular MATN3 in HCS-2/8 cell cultures resulted in increased expression of MATN3 and the chondrogenic transcription factor SOX9. Conversely, increased ectopic expression of MATN3 resulted in decreased expression of MATN3 and SOX9 in primary chondrocytes, while a mutant MATN3 lacking its first epidermal growth factor (EGF)-like domain failed to down-regulate SOX9.

CONCLUSION

Aberrant expression and processing of MATN3 are hallmarks of conventional cartilaginous neoplasms. A particular step in the maturation of MATN3 limits its processing through the secretion machinery, resulting in its intracellular accumulation upon increased expression. Soluble, secreted MATN3, however, down-regulates SOX9 at the messenger RNA and protein levels. The first EGF-like domain of MATN3 is a critical determinant of its regulatory activity toward SOX9. These activities of MATN3 suggest that its increased expression in osteoarthritis might contribute to the degeneration of articular cartilage.

Neuropilin-1 targeting photosensitization-induced early stages of thrombosis via tissue factor release

PURPOSE

This article characterizes the vascular effects following vascular-targeted photodynamic therapy with a photosensitizer which actively targets endothelial cells.

METHODS

This strategy was considered by coupling a chlorin to a heptapeptide targeting neuropilin-1 in human malignant glioma-bearing nude mice. A laser Doppler microvascular perfusion monitor was used to monitor microvascular blood perfusion in tumor tissue. Endothelial cells' ultra structural integrity was observed by transmission electron microscopy. The consequences of photosensitization on tumor vessels, tissue factor expression, fibrinogen consumption, and thrombogenic effects were studied by immunohistochemical staining.

RESULTS

Treatment of glioma-bearing mice with the conjugate showed a statistically significant tumor growth delay. Vascular effect was characterized by a decrease in tumor tissue blood flow at about 50% baseline during treatment not related to variations in temperature. This vascular shutdown was mediated by tumor blood vessels' congestion. A pro-thrombotic behavior of targeted endothelial cells in the absence of ultra structural changes led to the induction of tissue factor expression from the earliest times post-treatment. Expression of tissue factor-initiated thrombi formation was also related to an increase in fibrinogen consumption.

CONCLUSION

Using a peptide-conjugated photosensitizer targeting neuropilin-1, induction of tissue factor expression immediately post-treatment, led to the establishment of thrombogenic effects within the vessel lumen.

Expression of PPARgamma is reduced by medium supplementation with L-glutamine in human colorectal Caco-2 cells

Peroxisome proliferator-activated receptor-gamma (PPARgamma) belongs to the nuclear hormone receptor family. This receptor is implicated in colon cell differentiation and in colon cancer. Receptor activation by specific agonists has been shown to protect against colon cancer progression. PPARgamma protein content within cells is modulated by several mechanisms, including proteasome degradation, activation of Wnt signalling pathways and presence of fermentation products such as butyrate. Herein, we investigated the impact of L-glutamine on PPARgamma expression during the differentiation of Caco-2 cells grown in medium containing dialyzed fetal calf serum supplemented or not with L-glutamine. Using RT-PCR and Western blotting, we demonstrated that PPARgamma expression was decreased when L-glutamine was added to the medium. Using immunohistochemistry, we demonstrated that PPARgamma immunostaining was mainly found in cytoplasm when cells were cultured with L-glutamine while it was found in nuclei and cytoplasm when cells were grown without the addition of L-glutamine. Supershift retardation assays demonstrated a decrease of PPARgamma binding onto consensus peroxisome proliferator response element. We concluded that L-glutamine modulated PPARgamma expression in Caco-2 cells.

Assessment of apoptosis by immunohistochemistry to active caspase-3, active caspase-7, or cleaved PARP in monolayer cells and spheroid and subcutaneous xenografts of human carcinoma

Immunohistochemistry to active caspase-3, recently recommended for apoptosis detection, is inappropriate to detect apoptosis involving caspase-7. Cleavage of poly-ADP-ribose polymerase 1 (PARP-1), a major substrate of both caspases, is a valuable marker of apoptosis. Apoptosis evaluation induced in vitro either by paclitaxel or by photodynamic treatment (PDT) with Foscan in HT29 or KB monolayer cells and HT29 spheroids yielded a close percentage of labeled cells whatever the antibody used, whereas in control specimens, cleaved PARP (c-PARP) immunostaining failed to detect apoptosis as efficiently as active caspase-3 or -7 immunostaining. Studies in MDA-MB231 monolayer cells and HT29 xenografts either subjected or not subjected to Foscan-PDT resulted in a significant higher number of active caspase-3-labeled cells, although immunofluorescence analysis showed c-PARP and active caspase-3 perfectly colocalized in tumors. A restricted expression of c-PARP was obvious in the greater part of caspase-3 expressing cells from control tumor, whereas photosensitized tumors showed a higher number of cells expressing large fluorescent spots from both active caspase-3 and c-PARP. These results support the assumption that c-PARP expression was dependent on treatment-induced apoptosis. The absence of caspase-7 activation in some caspase-3-expressing cells undergoing Foscan-PDT shows the relevance of using antibodies that can discriminate caspase-dependent apoptotic pathways.

[A marginal zone-B cell lymphoma revealed by platelet satellitism and lympho-agglutination phenomenon around atypical lymphocytes]

A 48-year-old man, with persistent pyrexia, presented with thrombocytopenia and lymphocytosis. The peripheral blood smears showed atypical lymphocytes and a platelet satellitism phenomenon around atypical lymphocytes associated to lympho-agglutination. Platelet satellitism was exclusively observed with atypical lymphocytes in EDTA-treated blood and at room temperature. This phenomenon was not observed when adding normal plasma and could be reproduced several times. Flow cytometry analysis of the peripheral blood, cytological and histological studies revealed a marginal zone-B cell lymphoma. The mechanism underlying platelet satellitism is not fully understood, but is likely to involve an immunologic binding of EDTA-dependent antiplatelet autoantibodies directed against the platelets glycoprotein IIb/IIIa complex. The association between platelet satellitism and lymphoma could also involve a monoclonal Ig secreted by lymphoma cells.

Ferumoxtran-10 enhancement in orthotopic xenograft models of human brain tumors: an indirect marker of tumor proliferation?

PURPOSE

Ferumoxtran-10 belongs to the Ultra Small Particles of Iron Oxide (USPIO) class of contrast agents and induces delayed tumor enhancement in brain tumors, reflecting the trapping of iron oxide particles by the macrophages and activated microglia. The aim of the study was to compare Ferumoxtran-10 contrast enhancement in four human high-grade glioma xenograft models (TCG2, TCG3, TCG4, and U87) with different growing profiles.

MATERIALS AND METHODS

Fragments of human malignant glioma were orthotopically xenografted into the brain of four groups of nude mice. All mice underwent a MRI examination 24 h after intravenous administration of Ferumoxtran-10 (axial T1 SE weighted MR images). The contrast enhancement observed in the different tumor types was measured and was correlated to in vivo tumor growth and to histological parameters, such as proliferative tumor cell fraction, apoptosis, vascular density, and Perls' staining score.

RESULTS

A good relationship was observed: (a) between tumor-to-background contrast and proliferative index, (b) between tumor-to-background contrast and tumor growth, and (c) between tumor-to-background contrast and Perls' staining score. The registered MR enhancement contrasts were not influenced by apoptotic index and by vascular density in these experimental xenografts.

CONCLUSIONS

Tumor contrast enhancement 24 h after intravenous Ferumoxtran-10 administration seems to be well correlated to tumor proliferative index and tumor growth and could be used as an indirect marker of tumor proliferation.

Genetic analysis of peroxisome proliferator-activated receptor gamma1 splice variants in human colorectal cell lines

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the nuclear hormone receptor family. In colon, this transcription factor is involved in differentiation of absorptive cells. PPARgamma participates also in colon carcinogenesis and cancer progression. Two isoforms, namely PPARgamma1 and PPARgamma2, have been described. Recently, new PPARgamma1 transcripts whose translation raises PPARgamma1 protein have been characterised. They differ from each other by combination of untranslated exons localised in the 5' UTR of the PPARG gene. Here, we studied whether such a diversity of PPARgamma transcripts occurs in human colon cell models. Based on bioinformatic analysis, putative untranslated exons were identified in the human PPARG gene. By RT-PCR analysis, we have demonstrated that several of these untranslated exons are included in PPARgamma transcripts from colon-derived cell lines or in those derived from other tissue. Using HT-29 cells, changes in PPARgamma1 mRNA levels were observed after treatment with PPARgamma agonists such as pioglitazone and troglitazone. These modifications correlated with particular PPARgamma transcripts excluding the untranslated exon A2. HT-29 cells treatment with actinomycin D or cycloheximide showed that the presence of PPARgamma mRNA including exon A2 was dependent on de novo protein synthesis. We concluded that diverse PPARgamma1 mRNA exist in colorectal cells. Levels of PPARgamma1 transcript varied according to the phenotype of colon cell model used. We suggest that regulation of PPARgamma1 mRNA levels could be dependent in part on the composition of untranslated exon(s) in the 5' UTR of PPARgamma1 mRNA.

Les conséquences moléculaires de la fixation et de l’inclusion: exemple des acides nucléiques et des protéines

The scientific usefulness of the molecular data obtained from tissue analysis is related directly to the quality of the tissue specimen. The most ideal tissue specimen is the one that carries a complete and unaltered representation of the tissue in vivo. The aim of this review is to provide an overview of the effects of fixation and tissue processing on the content and integrity of nucleic acid and proteins.

Overexpression of endocan induces tumor formation

Endocan is a proteoglycan specifically secreted by endothelial cells. Through its glycan domains, endocan binds to hepatocyte growth factor and increases its mitogenic activity. Here, we show that human embryonic kidney 293 cells, which have been genetically engineered to overexpress endocan, form tumors when injected s.c. in SCID mice. Both the glycan and a phenylalanine-rich region of endocan are necessary for mediating tumor growth activity. Blocking the phenylalanine-rich region with a monoclonal antibody results in a marked reduction of tumor growth. Finally, we report that circulating levels of endocan are increased in mice with the endocan-expressing human embryonic kidney 293 cell tumors and in a series of adult patients with lung cancer. Taken together, these results suggest that (a) endothelial-derived endocan induces tumor growth, (b) antibodies to endocan may have therapeutic potential, and (c) circulating levels of endocan may eventually represent a novel marker for cancer.

Influence of Lewis antigen expression by Helicobacter pylori on bacterial internalization by gastric epithelial cells

The role of Helicobacter pylori lipopolysaccharide (LPS) Lewis antigens in infection is still not well known. We investigated the influence of Lewis antigen expression by H. pylori on its internalization by AGS cells and the epithelium of human gastric xenografts in nude mice using isogenic mutants in LPS biosynthetic genes. In vivo, colonization rates were unaffected by the change in H. pylori Lewis antigen expression, whereas the number of viable intracellular bacteria was significantly higher with wild-type H. pylori strains expressing Lewis antigens when compared to the isogenic mutants in both models. H. pylori strains expressing more Lewis X antigens (Le(x)) were internalized at a higher rate than those expressing less Le(x), type II Lewis antigens (Le(a) or Le(b)) alone, or no Lewis antigens. Thus, Lewis antigens appear to be involved in the internalization of H. pylori by the gastric epithelium.

Expression of peroxisome proliferator-activated receptors alpha and gamma in differentiating human colon carcinoma Caco-2 cells

The expression of peroxisome proliferator-activated receptors alpha (PPARalpha) and gamma (PPARgamma) was studied in the human adenocarcinoma Caco-2 cells induced to differentiate by long term culture (15 days). The differentiation of Caco-2 cells was attested by increases in the activities of sucrase-isomaltase and alkaline phosphatase (two brush border enzymes), fatty acyl-CoA oxidase (AOX) and catalase (two peroxisomal enzymes), by an elevation in the protein levels of villin (a brush border molecular marker), AOX, peroxisomal bifunctional enzyme (PBE), catalase and peroxisomal membrane protein of 70 kDa (PMP70). and by the appearance of peroxisomes. The expression of PPARalpha and PPARgamma was investigated by Western blotting, immunocytochemistry, Northern blotting and S1 nuclease protection assay during the differentiation of Caco-2 cells. The protein levels of PPARalpha, PPARgamma, and PPARgamma2 increased gradually during the time-course of Caco-2 cell differentiation. Immunocytochemistry revealed that PPARalpha and gamma were localized in cell nuclei. The PPARgamma1 protein was encoded by PPARgamma3 mRNA because no signal was obtained for PPARgamma1 mRNA using a specific probe in S1 nuclease protection assay. The amount of PPARgamma3 mRNA increased concomitantly to the resulting PPARgamma1 protein. On the other hand, the mRNA of PPARalpha and PPARgamma2 were not significantly changed, suggesting that the increase in their respective protein was due to an elevation of the translational rate. The role played by the PPAR subtypes in Caco-2 cell differentiation is discussed.

Morphologic and functional development of whole human fetal stomachs grafted into nude mice

To study in vivo the cellular differentiation and secretion of human developing fetal stomach, ethically and technically impossible to perform in utero, 256 fetal stomachs were xenografted. Human stomachs from 6- to 10-week-old fetuses were grafted for 1-273 days into nude mice. Biopsies for immunohistochemistry, hybridization and electron microscopy were taken and a catheter introduced into the human stomach. Macroscopic growth was fast and cells in S phase were numerous during the first 9 weeks, then the stomach size was stable and the gastric mucosa, of adult type, remained normal. In situ hybridization detected only a minute mouse mesenchymal chimerism in the graft. Chromogranin A, intrinsic factor and H+/K+ adenosine triphosphatase were immunohistolocally detected in epithelial cells 20 days after grafting, gastrin was detected after 30 days and pepsinogen after 60 days. The pH in gastric juice, which was at 8.0 +/- 0.1 from days 10-25, dropped from 4.39 +/- 1.80 at 30 days to 1.58 +/- 0.29 at 90 days. Intrinsic factor was stable and pepsin ranged from 6.8 +/- 7.8 to 134 +/- 51 units at 90 days. The differentiation of the epithelial cells in xenografts was very accelerated in comparison to that in utero.

[Formaldehyde fixation in the third millennium]

This review deals with the general principles and problems of formaldehyde fixation. After a short description of 1) formaldehyde methods of production, 2) chemical properties of formaldehyde solution, and 3) kinetic of formaldehyde binding in tissue, formaldehyde reactivity with the tissue biopolymers, proteins and cucleic acids mainly, are described. How formaldehyde fixation of tissues adversely affects the reactivity of cellular proteins with their respective specific antibody and the ways the most commonly used retrieval techniques in immunohistochemistry act are, thereafter, discussed. Finally, concerns that need to be dealt with when formalin-fixed specimens are used for genomic analysis and studies of DNA expression are highlighted.

Increased expression of the vascular endothelial growth factor is a pejorative prognosis marker in papillary thyroid carcinoma

Vascular endothelial growth factor (VEGF) is a potent stimulator of endothelial cell proliferation. It has been implicated in tumor growth of human thyroid carcinomas. Using the VEGF immunohistochemistry staining score, we correlated the level of VEGF expression with the metastatic spread of 19 cases of thyroid papillary carcinoma. The VEGF immunostaining score, ranging from 0-9, was determined as the multiplication of a percentage of labeled thyrocytes score (0, no labeling; 1, <30%; 2, 31--60%; 3, >61% of labeled thyrocytes) and an intensity score (0, no staining; 1, weak; 2, mild; 3, strong staining). The mean score +/- SD was 5.74 +/- 2.59 for all carcinomas. The mean score for metastatic papillary carcinoma was 8.25 +/- 1.13 vs. 3.91 +/- 1.5 for nonmetastatic papillary cancers (P < 0.001). By discriminant analysis, we found a threshold value of 6.0, with a sensitivity of 100% and a specificity of 87.5%. There were no statistical differences between metastatic and nonmetastatic carcinomas when age, tumor size, or thyroglobulin levels were considered. The VEGF immunostaining score seems to be a helpful marker for metastasis spread in differentiated thyroid cancers. An increased production of VEGF could assess an aggressive disease and be the hallmark of a trend to produce metastasis. We propose the VEGF immunostaining score as a marker for the prognosis in differentiated thyroid cancers. A value of 6 or more, should be considered as at high risk for metastasis threat, prompting the physician to institute a tight follow up of the patient.

[Paraneoplastic opsoclonus-myoclonus syndrome revealing T-cell lymphoma]

BACKGROUND

Nonrhythmic involuntary ocular oscillations and axial and segmentary myoclonia are associated in the opsoclonus-myoclonus syndrome. In adults, a paraneoplastic origin is generally found. We report the first of opsoclonus-myoclonus associated with non-Hodgkin's lymphoma.

CASE REPORT

A 66-year-old woman rapidly developed a typical opsoclonus-myoclonus syndrome within a few hours, presenting vertigo, cerebellous ataxia, multidirectional involuntary ocular movements and non-rhythmic axial and segmentary myoclonia. Brain computed tomography and magnetic resonance imaging demonstrated discrete diffuse anomalies of the white substance predominating in the pons. The cerebrospinal fluid showed discrete lymphocytosis. Antineuron antibodies were negative. No cause could be identified until the development 11 months later of pleomorphic T-cell mediastino-cervical lymphoma. The patient responded moderately to a CHOP regimen which had no effect on the opsoclonus-myoclonus syndrome. Death occurred after a 16-month course due to pulmonary complications.

DISCUSSION

Neuroblastoma and infectious causes predominate in opsoclonus-myoclonus syndromes observed in children; in adults, the predominant cause is cancer. Antineuron, anti-Ri and anti-Hu antibodies can be evidenced in some cases, arguing in favor of a paraneoplastic mechanism. Recent reports have evidenced MRI anomalies in the pons and the cerebellum, anatomically well correlated with the opsoclonus-myoclonus syndrome. Besides small-cell bronchogenic anaplastic cancer, the possibility of cancer of the breast and uterus, and both non-Hodgkin and Hodgkin lymphoma should be explored, knowing the cancer develops several month after the opsoclonus-myoclonus syndrome.

Evaluation of coupling of cobalamin to antisense oligonucleotides by thin-layer and reversed-phase liquid chromatography

We have evaluated by chromatography two strategies of oligonucleotide binding to vitamin B12 (cobalamin). The first one was based on a covalent linkage of aminooligonucleotide to carboxycobalamin in presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). Carboxycobalamin and EDC-cobalamin were eluted with a retention time of 16.5 and 21.6 min, respectively, in RP-HPLC, while aminooligonucleotide and oligonucleotide-cobalamin were coeluted at 19.4 and 19.8 min. In the second strategy, avidin was coupled to both biotinylated oligonucleotide and vitamin B12. Aminocobalamin and biotinylated cobalamin had respective retention times of 13 and 15.7 min in RP-HPLC and respective Rf values of 0.3 and 0.8 in thin-layer chromatography. Incubation of avidin with biotinylated cobalamin produced, in Superose 12 gel permeation, a peak with a retention time of 28 min, which corresponded to avidin-biotinylated cobalamin as it disappeared with an excess of either biotin or biotinylated oligonucleotide. In conclusion, we have prepared and purified by RP-HPLC and gel permeation chromatography an oligonucleotide-avidin-cobalamin complex which will be used as a vector complex of antisense oligonucleotides.

[Extra-cardiac rhabdomyoma of the fetal type]

Rhabdomyomas are benign tumors of striated muscle. They are distinguished by topographic data: cardiac or genital and by histological criteria: foetal or adult type. The foetal type is the most heterogeneous, with either a majority of immature cells or a mixture of maturing elements. This diversity has led to distinguish immature (or standard) foetal Rhabdomyomas from intermediate foetal Rhabdomyomas. One observation of this last type is reported. The authors highlight the essential characteristics of foetal Rhabdomyomas, however the exact meaning remains unclear: an anomaly in the differentiation of the striated muscle? or a true tumoral process through genetic anomaly?

[An exceptional variety of medulloblastoma: melanotic medulloblastoma]

We report a new case of melanotic medulloblastoma of the vermis in a 3 1/2 year old boy. This tumor showed a typical histological appearance with pseudoepithelial pigmented structures immunoreactive for S100 protein and vimentin. The tumor did not recur after total surgical removal and post operative radiation. However, after a 10 year follow-up, imaging demonstrated that a second tumor occurred in the left cerebellar hemisphere, which, on histological examination, was a typical glioblastoma. Hypothesis concerning the histogenesis of the second tumor, as well as a causal association with radiation therapy and possible contribution of growth hormone therapy are discussed.