Isabelle Salmon

Intramucosal adenocarcinoma arising under squamous re-epithelialisation of Barrett's oesophagus.

BACKGROUND Eradication of Barretts mucosa by thermal or photoablation combined with high doses of proton pump inhibitors is a potentially attractive strategy in the management of this preneoplastic condition. However, major concerns of this method are the persistence of residual metaplastic glands beneath the new squamous epithelium and the absence of any knowledge of its impact on long term outcome. CASE REPORT The case of an intramucosal adenocarcinoma diagnosed 18 months after apparently complete squamous re-epithelialisation achieved using argon plasma coagulation and high dose omeprazole (40 mg/daily) is reported in a 68 year old patient presenting initially with a Barretts oesophagus without dysplasia. Intramucosal adenocarcinoma was located under the new squamous layer and presented as a bulging area covered by the squamous epithelium. It probably originates from residual metaplastic glands after therapy although a pre-existing tumour cannot be definitely excluded. CONCLUSION This observation might question future application of this experimental endotherapy in non-dysplastic Barretts oesophagus. It suggests that the residual glands might still be premalignant and that the early diagnosis of neoplastic changes might be compromised by the squamous re-epithelialisation.

SOX2 controls tumour initiation and cancer stem-cell functions in squamous-cell carcinoma

Cancer stem cells (CSCs) have been reported in various cancers, including in skin squamous-cell carcinoma (SCC). The molecular mechanisms regulating tumour initiation and stemness are still poorly characterized. Here we find that Sox2, a transcription factor expressed in various types of embryonic and adult stem cells, was the most upregulated transcription factor in the CSCs of squamous skin tumours in mice. SOX2 is absent in normal epidermis but begins to be expressed in the vast majority of mouse and human pre-neoplastic skin tumours, and continues to be expressed in a heterogeneous manner in invasive mouse and human SCCs. In contrast to other SCCs, in which SOX2 is frequently genetically amplified, the expression of SOX2 in mouse and human skin SCCs is transcriptionally regulated. Conditional deletion of Sox2 in the mouse epidermis markedly decreases skin tumour formation after chemical-induced carcinogenesis. Using green fluorescent protein (GFP) as a reporter of Sox2 transcriptional expression (SOX2–GFP knock-in mice), we showed that SOX2-expressing cells in invasive SCC are greatly enriched in tumour-propagating cells, which further increase upon serial transplantations. Lineage ablation of SOX2-expressing cells within primary benign and malignant SCCs leads to tumour regression, consistent with the critical role of SOX2-expressing cells in tumour maintenance. Conditional Sox2 deletion in pre-existing skin papilloma and SCC leads to tumour regression and decreases the ability of cancer cells to be propagated upon transplantation into immunodeficient mice, supporting the essential role of SOX2 in regulating CSC functions. Transcriptional profiling of SOX2–GFP-expressing CSCs and of tumour epithelial cells upon Sox2 deletion uncovered a gene network regulated by SOX2 in primary tumour cells in vivo. Chromatin immunoprecipitation identified several direct SOX2 target genes controlling tumour stemness, survival, proliferation, adhesion, invasion and paraneoplastic syndrome. We demonstrate that SOX2, by marking and regulating the functions of skin tumour-initiating cells and CSCs, establishes a continuum between tumour initiation and progression in primary skin tumours.

Infliximab in patients with primary Sjögren's syndrome : A pilot study

OBJECTIVE Tumor necrosis factor alpha (TNFalpha) is a proinflammatory cytokine involved in the pathogenesis of Sjögrens syndrome (SS), and blockade of TNFalpha may reduce the activity of the disease. The purpose of this study was to evaluate the safety and potential efficacy of infliximab, a chimeric human-mouse anti-TNFalpha monoclonal antibody, in patients with active primary SS. METHODS This was a single-center, open-label pilot study. Sixteen patients with active primary SS received 3 infusions of infliximab (3 mg/kg) at 0, 2, and 6 weeks. Standard clinical assessment, complete ophthalmologic testing, and functional evaluation of salivary flow were performed at baseline and at weeks 2, 6, 10, and 14. RESULTS All patients completed the study. There was statistically significant improvement in all clinical and functional parameters, including global assessments (patients global assessment, patients assessment of pain and fatigue, physicians global assessment), erythrocyte sedimentation rate, salivary flow rate, the Schirmer I test, tender joint count, fatigue score, and dry eyes and dry mouth. This clinical benefit was observed at week 2 and was maintained throughout the study and the 2-month followup period. The treatment was well tolerated in all patients, and no significant adverse events were seen. No lupus-like syndrome was observed, and no anti-double-stranded DNA antibodies were observed that were attributable to infliximab therapy. CONCLUSION In patients with active primary SS, a loading-dose regimen of 3 infusions of infliximab provided a fast and significant clinical benefit without major adverse reactions. It was possible to maintain statistically significant improvement for up to 8 weeks after the third infusion.

Galectins Are Differentially Expressed in Supratentorial Pilocytic Astrocytomas, Astrocytomas, Anaplastic Astrocytomas and Glioblastomas, and Significantly Modulate Tumor Astrocyte Migration

Galectins, a family of mammalian lectins with specificity to β‐galactosides, are involved in growth‐regulatory mechanisms and cell adhesion. A relationship is assumed to exist between the levels of expression of galectins and the level of malignancy in human gliomas. A comparative study of this aspect in the same series of clinical samples is required to prove this hypothesis. Using computer‐assisted microscopy, we quantitatively characterized by immunohistochemistry the levels of expression of galectins‐1, ‐3 and‐8 in 116 human astrocytic tumors of grades I to IV. Extent of transcription of galectins‐1, ‐3, and ‐8 genes was investigated in 8 human glioblastoma cell lines by means of RT‐PCR techniques. Three of these cell lines were grafted into the brains of nude mice in order to characterize in vivo the galectins‐1, ‐3 and ‐8 expression in relation to the patterns of the tumor invasion of the brain. The role of galectin‐1, ‐3 and ‐8 in tumor astrocyte migration was quantitatively determined in vitro by means of computer‐assisted phase‐contrast videomicroscopy. The data indicate that the levels of galectin‐1 and galectin‐3 expression significantly change during the progression of malignancy in human astrocytic tumors, while that of galectin‐8 remains unchanged. These three galectins are involved in tumor astrocyte invasion of the brain parenchyma since their levels of expression are higher in the invasive parts of xenografted glioblastomas than in their less invasive parts. Galectin‐3, galectin‐1, and to a lesser extent galectin‐8, markedly stimulate glioblastoma cell migration in vitro. Since bands for the transcripts of human galectins‐2, ‐4 and ‐9 were apparently less frequent and intense in the 8 human glioblastoma cell lines, this system provides an excellent model to assign defined roles to individual galectins and delineate overlapping and distinct functional aspects.

Refined prognostic evaluation in colon carcinoma using immunohistochemical galectin fingerprinting

Knowledge of the expression of the galectins in human colon carcinomas is mainly restricted to galectin‐3 and, to a lesser extent, galectin‐1. The current study analyzed the prognostic values contributed by galectin‐1, galectin‐3, galectin‐4, and galectin‐8 in cases of colon carcinoma.

Galectin-1 is highly expressed in human gliomas with relevance for modulation of invasion of tumor astrocytes into the brain parenchyma.

Protein (lectin)‐carbohydrate interaction is supposed to be relevant for tumor cell behavior. The aims of the present work are to investigate whether galectin‐1 modulates migration/invasion features in human gliomas in vitro, whether it can be detected in human gliomas immunohistochemically, and whether its expression is attributable to certain glioma subgroups with respect to invasion and prognosis. For this purpose, we quantitatively determined (by computer‐assisted microscopy) the immunohistochemical expression of galectin‐1 in 220 gliomas, including 151 astrocytic, 38 oligodendroglial, and 31 ependymal tumors obtained from surgical resection. We also xenografted three human glioblastoma cell lines (the H4, U87, and U373 models) into the brains of nude mice in order to characterize the in vivo galectin‐1 expression pattern in relation to tumor invasion of the normal brain parenchyma. In addition, we characterized the role in vitro of galectin‐1 in U373 tumor astrocyte migration and kinetics. Our data reveal expression of galectin‐1 in all human glioma types with no striking differences between astrocytic, oligodendroglial, and ependymal tumors. The level of galectin‐1 expression correlated with the grade in the group of astrocytic tumors only. Furthermore, immunopositivity of high‐grade astrocytic tumors from patients with short‐term survival periods was stronger than that of tumors from patients with long‐term survivals. In human glioblastoma xenografts, galectin‐1 was preferentially expressed in the more invasive parts of these xenografts. In vitro experiments revealed that galectin‐1 stimulates migration of U373 astrocytes. GLIA 33:241–255, 2001.

Upregulation of galectins-1 and -3 in human colon cancer and their role in regulating cell migration

To probe the potential contribution of β‐galactoside‐contributing epitopes and receptor proteins (gal‐1 and gal‐3) to colon malignancy, we first examined the expression of galectins and binding sites in clinical specimens by lectin and immunohistochemistry. Sixty‐seven colonic surgical resections were studied, including 10 normal, 10 mild dysplasias, 10 severe dysplasias and 37 cancers. gal‐1 and gal‐3 were expressed in variable amounts in the epithelial cells and the connective tissue of normal colon. Their expression significantly increased with the degree of dysplasia, suggesting that gal‐1 and gal‐3 and their binding sites are related to malignant progression, while gal‐8 has been associated with suppressor activity. To study the functional aspects, the influence of these galectins on the migration of 4 human colorectal cancer cell lines (HCT‐15, LoVo, DLD‐1, CoLo201) was studied. In agreement with histopathologic monitoring, these tumor cells were found to produce gal‐3, while only CoLo201 was positive for gal‐1. Except for DLD‐1 and gal‐1, the lines exhibited gal‐1 binding sites on the surface, prompting study by computer‐assisted videomicroscopy of the effect on cell migration of the presence of galectin on the culture substrate. The level of cell migration for HCT‐15, LoVo and CoLo201 cells was significantly reduced by 0.15 μg/cm2 gal‐1, and the presence of a blocking antibody at least reduced this effect. gal‐3 significantly reduced cell migration in all 4 of the in vitro cell lines.

Bosentan for the prevention of overcirculation-induced experimental pulmonary arterial hypertension.

Background—The dual endothelin-receptor antagonist bosentan has been reported to improve pulmonary arterial hypertension, but the role of endothelins in the pathogenesis of the condition remains uncertain. We investigated the roles of endothelin-1 (ET-1), nitric oxide (NO), vascular endothelial growth factor (VEGF), and tenascin in overcirculation-induced pulmonary hypertension in piglets, as a model of early pulmonary arterial hypertension, with or without bosentan therapy. Methods and Results—Thirty 3-week-old piglets were randomized to placebo or to bosentan 15 mg/kg BID after the anastomosis of the left subclavian artery to the pulmonary arterial trunk or after a sham operation. Three months later, the animals underwent a hemodynamic evaluation followed by cardiac and pulmonary tissue sampling for morphometry, immunohistochemistry, and real-time quantitative PCR. Chronic systemic-to-pulmonary shunting increased circulating plasma ET-1, pulmonary mRNA for ET-1, ETB receptor, inducible NO synthase, VEGF, and pulmonary ET-1 and VEGF proteins. There were increases in myocardial mRNA for ETA receptor and VEGF and in myocardial VEGF protein. Pulmonary and myocardial tissue mRNA for tenascin did not change. Normalized-flow pulmonary artery pressure increased from 20 (2) to 33 (1) mm Hg [mean (SEM)], arteriolar medial thickness increased on average by 83%, and these changes were completely prevented by bosentan therapy. Right ventricular end-systolic elastance increased in proportion to pulmonary arterial elastance with or without bosentan. Conclusions—Experimental overcirculation-induced pulmonary arterial hypertension appears to be causally related to an activation of the pulmonary ET-1 system and as such is completely prevented by the dual endothelin receptor antagonist bosentan.

Expression of endoplasmic reticulum stress markers in the islets of patients with type 1 diabetes.

Aims/hypothesisEndoplasmic reticulum (ER) stress may play a role in cytokine-mediated beta cell death in type 1 diabetes, but it remains controversial whether ER stress markers are present in islets from type 1 diabetic individuals. Therefore, we evaluated by immunostaining the expression of markers of the three main branches of the ER stress response in islets from 13 individuals with and 15 controls without type 1 diabetes (eight adults and seven children).MethodsAntibodies against the ER stress markers C/EBP homologous protein (CHOP), immunoglobulin heavy chain (BIP) and X-box binding protein 1 (XBP-1) were validated using HeLa cells treated with the ER stressor thapsigargin. These antibodies were then used to stain serial sections of paraffin-embedded pancreas from type 1 diabetic and non-diabetic individuals; samples were also immunostained for CD45, insulin and glucagon. Immunostaining intensities of the ER stress markers were quantified using a software-based, unbiased quantitative approach.ResultsIslets from individuals with type 1 diabetes showed increased levels of CHOP and, at least for insulitis-positive and beta cell-containing islets, BIP. XBP-1 expression was not, however, increased.Conclusions/interpretationIslet cells from individuals with type 1 diabetes display a partial ER stress response, with evidence of the induction of some, but not all, components of the unfolded protein response.

Evidence for stimulation of tumor proliferation in cell lines and histotypic cultures by clinically relevant low doses of the galactoside-binding mistletoe lectin, a component of proprietary extracts.

The toxic galactoside-specific lectin from mistletoe, a component of proprietary extracts with unproven efficacy in oncology, exhibits capacity to trigger enhanced secretion of proinflammatory cytokines at low doses (ng/ml or ng/kg body weight) and reductions of cell viability with increasing concentrations. To infer any tumor selectivity of this activity, cytofluorimetric and cell growth assays with a variety of established human tumor cell lines were performed. Only quantitative changes were apparent, and the toxicity against tumor cells was within the range of that of the tested fibroblast preparations from 5 donors. No indication for any tumor selectivity was observed. In kinetic studies with 8 sarcoma and 4 melanoma lines, this evidence for quantitative variability of the response in interindividual comparison was further underscored. At 50 pg lectin/ml × 105 cells, even a growth-stimulatory impact was noted in 5 of 12 tested cases. To mimic in vivo conditions with presence of cytokine-secreting inflammatory and stromal cells, exposure to the lectin was extended to histotypic cultures established from 30 cases of surgically removed tumor. As salient result, 5 specimens from 4 of the 8 tested tumor classes responded with a significant increase of [3H]-thymidine incorporation relative to controls during the culture period of 72 hours, when the lectin was present at a concentration in the described immunomodulatory range (1 ng/ml). A relation of this activity to the extent of the actual proliferative status of the reactive samples could not be delineated. Therefore, a non-negligible percentage of the established tumor cell lines (e.g., 3 from 8 sarcoma lines) can be markedly stimulated by the lectin at a very low dose and with dependence on the cell type. Furthermore, the feasibility to elicit a significant growth enhancement is likewise documented for human tumor explants in 16.6% of the examined cases. In view of the uncontrolled application of lectin-containing extracts in alternative/complementary medicine, the presented results on unquestionably adverse lectin-dependent effects in two culture systems call for rigorous examination of the clinical safety of this unconventional, scientifically entirely experimental treatment modality.