T-cell and NK-cell infiltration into solid tumors: a key limiting factor for efficacious cancer immunotherapy.

Cancer immunotherapy has great promise, but is limited by diverse mechanisms used by tumors to prevent sustained antitumor immune responses. Tumors disrupt antigen presentation, T/NK-cell activation, and T/NK-cell homing through soluble and cell-surface mediators, the vasculature, and immunosuppressive cells such as myeloid-derived suppressor cells and regulatory T cells. However, many molecular mechanisms preventing the efficacy of antitumor immunity have been identified and can be disrupted by combination immunotherapy. Here, we examine immunosuppressive mechanisms exploited by tumors and provide insights into the therapies under development to overcome them, focusing on lymphocyte traffic.

Role of hepatitis C virus genotype 3 in liver fibrosis progression : a systematic review and meta-analysis ; et, Impact of nurse vaccination program on hepatitis B immunity in a Swiss HIV clinic

Rôle du génotype 3 du virus de l'hépatite C dans la progression de la fibrose hépatique, une revue systématique avec méta-analyse. On estime à 170 millions le nombre de personnes atteintes d'hépatite C chronique dans le monde. La principale conséquence de cette maladie est la fibrose du foie, qui évolue plus ou moins rapidement, pour aboutir au développement d'une cirrhose et/ou d'un hépatocarcinome. Certains des facteurs accélérateurs de la fibrose, comme l'âge avancé au moment de l'infection, le sexe masculin, la consommation d'alcool, sont bien connus. On a longtemps considéré que les six différents génotypes viraux n'influençaient pas la progression de la fibrose. Des études récentes ont cependant suggéré que certains génotypes, en particulier ie génotype 3, pouvaient entraîner une fibrose plus rapide. Le but de ce travail de thèse était de déterminer à l'aide d'une méta-analyse le rôle du génotype viral dans la progression de la fibrose dans l'infection chronique au virus de l'hépatite C. Les études ont été sélectionnées dans la littérature médicale à partir d'une série de mots-clés. Le degré de fibrose a été estimé par biopsie, en utilisant le score Metavir. Deux types d'études ont décrits de manière différente la durée d'infection. Les premières ont calculé la progression de la fibrose depuis le moment estimée de l'infection (« études avec une biopsie »), les secondes ont exprimés cette durée comme étant l'intervalle entre deux biopsies (« études avec deux biopsies »). L'analyse a permis d'identifier 8 études avec une biopsie pour un collectif total de 3182 patients ainsi que 8 études avec deux biopsies pour un collectif de 896 patients. Dans une méta-analyse de type « random effect », le rapport de cote pour l'association du génotype 3 avec une fibrose accélérée est de 1.52 (95% IC 1.12-2.07, p=0.007) pour les études à une biopsie. Pour les études à deux biopsies, le rapport de cote pour cette association est de 1.37 (95% IC 0.87-2.17, P=0.17). Cette étude montre que les patients avec une hépatite C chronique due au génotype 3 ont une progression de fibrose plus rapide que ceux qui sont infectés par les autres génotypes. Alors que la méta-analyse des études avec une biopsie est clairement significative, celle des études avec deux biopsies est au-dessous du seuil de significativité. Les études à deux biopsies peuvent être limitées par plusieurs facteurs, comprenant un « biais d'indication » (seuls les patients évoluant rapidement vers la cirrhose ont plus de risque d'avoir une deuxième biopsie), une durée d'observation très courte (5 années comparée à 13 années pour les études à 2 biopsies), et un nombre de patient limité (896 pour le études à 2 biopsies comparé à 3182 pour les études à 1 biopsie). Impact d'un programme de vaccination sur l'immunité contre l'hépatite Β dans une clinique suisse du VIH Le virus de l'hépatite Β cause une infection aigûe dont la symptomatologie varie d'une présentation subclinique à une progression fulminante. Dans une minorité de cas, l'infection aigiie est suivie d'une infection chronique pouvant évoluer vers une cirrhose hépatique et/ou un hépatocarcinome. La prévalence de l'hépatite Β aiguë et chronique chez les personnes vivant avec le virus d'immunodéficience humaine (VIH) est supérieure à celle de la population générale. Par ailleurs la co-infection avec le virus du VIH entraine une progression plus rapide de l'hépatite B. Dès lors, l'immunité pour le virus de l'hépatite Β représente un facteur primordial de prévention dans la population infectée par le virus de l'HIV. Bien que l'administration d'un vaccin contre l'hépatite Β soit particulièrement recommandée chez tous les individus infectés par le VIH, la couverture vaccinale dans cette population est souvent insuffisante. Le but de cette étude était de déterminer l'état d'immunisation contre le virus de l'hépatite Β dans la population infectée par le VIH de la cohorte Suisse HIV et d'analyser l'efficacité d'un programme de vaccination administré par le personnel soignant. L'immunité avant et après intervention dans notre centre a été comparée aux autres centres de la cohorte HIV en Suisse. L'immunité pour le centre d'intervention a passé de 32% avant intervention à 76% après intervention alors que pour les autres centres, l'immunité n'a progressé que de 33% à 39% dans le même laps de temps (n=2712, P=0.001). Cette étude montre qu'un contrôle systématique de l'immunité par du personnel soignant augmente de manière significative l'immunité pour le vaccin de l'hépatite Β dans la population HIV.

Expression of dual angiogenic/neurogenic growth factors in human primary brain tumors.

Brain tumors, benign or malignant, are characterized by a very high degree of vascularization. Recent accumulating evidence suggests that during development the neuronal wiring follows the same routes as the vasculature and that these two systems may share some of the same factors for guidance. Thus, expression of dual angiogenic/neurogenic growth factors was evaluated by in situ hybridization in human primary brain tumors of three different types, i.e., astrocytomas, oligodendrogliomas, and ependymomas, of increasing grades, in relation with the grade and type of the tumor. For this evaluation we selected vascular endothelial growth factor (VEGF-A) and its receptors VEGF-R1 and VEGF-R2 and the neuropilins 1 and 2 (NRP-1 and NRP-2), which have proangiogenic properties, platelet-derived growth factor (PDGF) receptor-beta (PDGF-Rβ), which is required for the functional maturation of blood vessels, the ephrins and their Eph receptors, angiotensinogen (AGT) and thrombospondin-2 (TSP-2), which have potential antiangiogenic properties, and netrin-1 (Net-1), which regulates vascular architecture. We show that the expression of the VEGF-NRP system, PDGF-Rβ, TSP-2, AGT, and Net-1 are differentially regulated, either increased or decreased, in relation with the type and grade of the tumor, whereas regulation of the ephrinB system does not seem to be relevant in these human brain tumors.

Estrogen-dependent in vitro transcription from the vitellogenin promoter in liver nuclear extracts.

One approach to analyzing the molecular mechanisms of gene expression in vivo is to reconstitute these events in cell-free systems in vitro. Although there is some evidence for tissue-specific transcription in vitro, transcriptionally active extracts that mimic a steroid hormone-dependent enhancement of transcription have not been described. In the study reported here, nuclear extracts of liver from the frog Xenopus laevis were capable of estrogen-dependent induction of a homologous vitellogenin promoter that contained the estrogen-responsive element.

Benefit of anti-HER2-coated paclitaxel-loaded immuno-nanoparticles in the treatment of disseminated ovarian cancer: Therapeutic efficacy and biodistribution in mice.

The benefit of polymeric immuno-nanoparticles (NPs-Tx-HER), consisting of paclitaxel (Tx)-loaded nanoparticles coated with anti-HER2 monoclonal antibodies (Herceptin, trastuzumab), in cancer treatment was assessed in a disseminated xenograft ovarian cancer model induced by intraperitoneal inoculation of SKOV-3 cells overexpressing HER2 antigens. The study was focused on the evaluation of therapeutic efficacy and biodistribution of NPs-Tx-HER compared to other Tx formulations. The therapeutic efficacy was determined by two methods: bioluminescence imaging and survival rate. The treatment regimen consisted in an initial dose of 20mg/kg Tx administered as 10mg/kg intravenously (IV) and 10mg/kg intraperitonealy (IP), followed by five alternative IP and IV injections of 10mg/kg Tx every 3 days. The bioluminescence study has clearly shown the superior anti-tumor activity of NPs-Tx-HER compared to free Tx. As a confirmation of these results, a significantly longer survival of mice was observed for NPs-Tx-HER treatment compared to free Tx, Tx-loaded nanoparticles coated with an irrelevant mAb (Mabthera, rituximab) or Herceptin alone, indicating the potential of immuno-nanoparticles in cancer treatment. The biodistribution pattern of Tx was assessed on healthy and tumor bearing mice after IV or IP administration. An equivalent biodistribution profile was observed in healthy mice for Tx encapsulated either in uncoated nanoparticles (NPs-Tx) or in NPs-Tx-HER. No significant difference in Tx biodistribution was observed after IV or IP injection, except for a lower accumulation in the lungs when NPs were administered by IP. Encapsulated Tx accumulated in the organs of the reticulo-endothelial system (RES) such as the liver and spleen, whereas free Tx had a non-specific distribution in all tested organs. Compared to free Tx, the single dose injection (IV or IP) of encapsulated Tx in mice bearing tumors induced a higher tumor accumulation. However, no difference in overall tumor accumulation between NPs-Tx-HER and NPs-Tx was observed. In conclusion, the encapsulation of Tx into NPs-Tx-HER immuno-nanoparticles resulted in an improved efficacy of drug in the treatment of disseminated ovarian cancer overexpressing HER2 receptors.

Phenotyping of 60 cultured human gliomas and 34 other neuroectodermal tumors by means of monoclonal antibodies against glioma, melanoma and HLA-DR antigens.

The reactivity spectrum of three monoclonal antibodies (Mabs) to human malignant glioma, five Mabs to melanomas and one Mab anti-HLA-DR was investigated by an indirect antibody binding radioimmunoassay on a panel of cells derived from 60 glioma lines, including 47 malignant astrocytomas, 11 low-grade astrocytomas and two malignant ependymomas as well on cells from 12 melanoma, three neuroblastoma, three medulloblastoma, two schwannoma, two retinoblastoma, two choroïd plexus papilloma, ten meningioma and 12 unrelated tumor lines. The anti-glioma Mabs BF7 and GE2 reacted preferentially with gliomas, while the anti-glioma Mab CG12 reacted with gliomas, melanomas, neuroblastomas and medulloblastomas. The five anti-melanoma Mabs reacted with gliomas, neuroblastomas and medulloblastomas. The anti-HLA-DR Mab D1-12 reacted with gliomas, melanomas and some meningiomas. On the basis of the data presented, we describe three different antigenic systems; the first one is glioma-associated, the second one is related to differentiation antigens expressed on cells derived from the neuroectoderm and the third is represented by HLA-DR antigens which are expressed not only on B-lymphoblastoid cells but also on melanomas and gliomas.

Diagnostic et traitement des tumeurs intra-oculaires chez l'enfant [Diagnosis and treatment of intraocular tumors in the child]

PURPOSE: To remind of the absolute necessity for early diagnosis in the presence of ocular signs in children giving rise to possible intraocular tumours. METHOD: Based on our own experience of intraocular tumours in children, together with findings from the literature, diagnostic criteria and methods of treatment are presented. RESULTS: Retinoblastoma is the predominant cause of intraocular tumours in children, representing over 80% of cases under the age of 15 years. Other diseases may give rise to the same initial signs, usually leukocoria, sometimes strabismus, more rarely other atypical signs. Elements taken into account for diagnosis include age, sex, laterality, heredity, size of the globe, clinical aspect of the tumours, presence of calcifications and vitreous seeding. Full fundus examination under general anaesthetic is usually necessary. Biological examination, ultrasonography, computerized tomography and MRI enable an accurate diagnosis to be made in the majority of doubtful cases. The management of retinoblastoma is adapted for each individual case from the wide range of treatments available. Enucleation, radioactive applicators (...), brachytherapy (...), cryo- and photocoagulation represent classical measures. Primary chemotherapy, combined with other treatments such as thermotherapy, has become the treatment of choice in those cases where external beam radiotherapy has been used up to now, or in some instances before enucleation. Enucleation is usually carried out for medullo-epitheliomas, but brachytherapy may offer an alternative. CONCLUSION: Any unexplained ocular sign in children should be considered as a possible retinoblastoma, making an accurate and certain diagnosis imperative. Early treatment may save not only the life but also the vision of patients carrying this highly malignant lesion.

Tumeurs de l'appareil locomoteur: de la simple "bosse" a la prise en charge multidisciplinaire [Tumors of the musculoskeletal system: from the "lumps" to multidisciplinary care].

Management of musculoskeletal tumours usually begins with the appearance of a lump or bump, or the onset of unspecific symptoms. A poor initial work-up, a faulty biopsy or an inadequate resection may have a severe impact on the prognosis, including re-interventions, amputation, local recurrence or systemic spread of the disease. The patient with a suspicious lesion should be referred to a "sarcoma centers" where a planned and well-performed diagnostic work-up will allow a precise diagnosis in terms of histology and staging. After a multidisciplinary discussion of the case, an accurate treatment plan is established. Such an approach allows an adequate patient management, often with a positive impact on the survival and functional outcome.

Migrated foreign body liver abscess: illustrative case report, systematic review, and proposed diagnostic algorithm.

Pyogenic liver abscess is a severe condition and a therapeutic challenge. Treatment failure may be due to an unrecognized ingested foreign body that migrated from the gastrointestinal tract. There has recently been a marked increase in the number of reported cases of this condition, but initial misdiagnosis as cryptogenic liver abscess still occurs in the majority of cases. We conducted the current study to characterize this entity and provide a diagnostic strategy applicable worldwide. To this end, data were collected from our case and from a systematic review that identified 59 well-described cases. Another systematic review identified series of cryptogenic-and Asian Klebsiella-liver abscess; these data were pooled and compared with the data from the cases of migrated foreign body liver abscess. The review points out the low diagnostic accuracy of history taking, modern imaging, and even surgical exploration. A fistula found through imaging procedures or endoscopy warrants surgical exploration. Findings suggestive of foreign body migration are symptoms of gastrointestinal perforation, computed tomography demonstration of a thickened gastrointestinal wall in continuity with the abscess, and adhesions seen during surgery. Treatment failure, left lobe location, unique location (that is, only 1 abscess location within the liver), and absence of underlying conditions also point to the diagnosis, as shown by comparison with the cryptogenic liver abscess series. This study demonstrates that migrated foreign body liver abscess is a specific entity, increasingly reported. It usually is not cured when unrecognized, and diagnosis is mainly delayed. This study provides what we consider the best available evidence for timely diagnosis with worldwide applicability. Increased awareness is required to treat this underestimated condition effectively, and further studies are needed.

Colorectal cancer metastasis: the DNA repair inhibitor Dbait increases sensitivity to hyperthermia and improves efficacy of radiofrequency ablation.

PURPOSE: To assess the usefulness of combining hyperthermia with a DNA repair inhibitor (double-strand break bait [Dbait]) and its potential application to radiofrequency ablation (RFA) in a preclinical model of human colorectal cancer. MATERIALS AND METHODS: The local ethics committee of animal experimentation approved all investigations. First, the relevance was assessed by studying the survival of four human colorectal adenocarcinoma cell cultures after 1 hour of hyperthermia at 41°C or 43°C with or without Dbait. Human colon adenocarcinoma cells (HT-29) were grafted subcutaneously into nude mice (n = 111). When tumors reached approximately 500 mm(3), mice were treated with Dbait alone (n = 20), sublethal RFA (n = 21), three different Dbait schemes and sublethal RFA (n = 52), or a sham treatment (n = 18). RFA was performed to ablate the tumor center alone. To elucidate antitumor mechanisms, 39 mice were sacrificed for blinded pathologic analysis, including assessment of DNA damage, cell proliferation, and tumor necrosis. Others were monitored for tumor growth and survival. Analyses of variance and log-rank tests were used to evaluate differences. RESULTS: When associated with mild hyperthermia, Dbait induced cytotoxicity in all tested colon cancer cell lines. Sublethal RFA or Dbait treatment alone moderately improved survival (median, 40 days vs 28 days for control; P = .0005) but combination treatment significantly improved survival (median, 84 days vs 40 days for RFA alone, P = .0004), with approximately half of the animals showing complete tumor responses. Pathologic studies showed that the Dbait and RFA combination strongly enhances DNA damage and coagulation areas in tumors. CONCLUSION: Combining Dbait with RFA sensitizes the tumor periphery to mild hyperthermia and increases RFA antitumor efficacy.

Limited sampling strategies for monitoring tacrolimus in paediatric liver transplant recipients

Ce travail de recherche a été réalisé dans le laboratoire de pharmacologie clinique, au Centre Hospitalier Universitaire Sainte-Justine, à Montréal. C'est une étude rétrospective basée sur le suivi thérapeutique du Tacrolimus prescrit chez les enfants après transplantation hépatique. Ce suivi est nécessaire car le Tacrolimus possède une importante variabilité pharmacocinétique inter et intra-individuelle ainsi qu'un index thérapeutique très étroit. Actuellement, l'individualisation des doses prescrites est basée sur la mesure de la concentration de base - du médicament dans le sang (C0), mais des études récentes montrent que cette mesure ne reflète pas précisément l'exposition du Tacrolimus dans l'organisme chez les enfants. Le meilleur reflet de cette exposition est la mesure de l'aire sous la courbe (AUC). Cependant, cette dernière implique la mesure de multiples concentrations tout au long de l'intervalle entre 2 doses de médicament (Tacrolimus: 12 heures) ce qui est long, cher et impraticable en ambulatoire. De nouvelles méthodes utilisant un nombre limité de prélèvements ont donc été développées pour prédire au mieux cette AUC. Ce sont les "Limited sampling strategies" ou LSS. La plupart de ces LSS pour le Tacrolimus ont été développées et validées chez des patients transplantés adultes et leur application directe chez les transplantés pédiatriques n'est pas possible en raison de différences importantes au niveau des paramètres pharmacocinétiques du médicament entre ces deux populations. Aussi, le but de ce travail était de développer et valider, pour la première fois, des LSS chez les enfants transplantés hépatiques. Pour cela, une analyse de 36 profils pharmacocinétiques de 28 patients transplantés hépatiques âgés de 0.4- 18.5 ans a été effectuée. Tous les profils ont été réalisés au Centre Hospitalier Universitaire Sainte-Justine entre janvier 2007 et janvier 2009. Les LSS comportant au maximum 4 mesures de concentration ont été développées en utilisant une analyse de régression multiple. Parmi tous les modèles obtenus, cinq ont été sélectionnés sur la base de critères précis puis validés selon la méthode décrite par Sheiner et Beal.¦Les résultats montrent que ces cinq modèles peuvent prédire l'AUC du Tacrolimus avec une précision cliniquement acceptable de ± 15% alors que la C0 présente la plus faible corrélation avec l'AUC.¦En conclusion, cette étude confirme que la C0 ne permet pas de prédire de manière efficace l'exposition du Tacrolimus dans l'organisme dans notre population de patients pédiatriques contrairement aux LSS analysées qui offrent une méthode pratique et fiable. Par ailleurs, en permettant d'obtenir une estimation précise et simplifiée de l'AUC complète du Tacrolimus chez les patients, ces LSS ouvrent la porte à de futures études prospectives visant à mieux définir l'AUC cible du médicament et à déterminer si le suivi basé sur la mesure de l'AUC est plus efficace et plus sûr que celui basé sur la mesure de la C0.

Antibody-fluorescein conjugates for photoimmunodiagnosis of human colon carcinoma in nude mice.

To improve the detectability of tumors by light-induced fluorescence, the use of monoclonal antibodies (MoAb) as carriers of fluorescent molecules was studied. As a model for this approach, the biodistribution of an anticarcinoembryonic antigen (CEA) MoAb coupled to fluorescein was studied in mice bearing a human colon carcinoma xenograft. In vitro, such conjugates with fluorescein-MoAb molar ratios ranging from four to 19, doubly labeled with 125I, showed more than 82% binding to immobilized CEA. In vivo, conjugates with a fluorescein-MoAb molar ratio of ten or less resulted in a tumor uptake of more than 30% of the injected dose of radioactivity per gram tumor at 24 hours. Tumor to liver, kidney, and muscle ratios of 20, 30 and 72, respectively, were obtained 48 hours after injection of the 125I-MoAb-(fluorescein)10 conjugate. The highest fluorescence intensity was always obtained for the tumor with the anti-CEA MoAb conjugate; whereas in control mice injected with fluoresceinated control immunoglobulin G1, no detectable increase in tumor fluorescence was observed. To compare these results with a classically used dye, mice bearing the same xenografts received 60 micrograms of Photofrin II. The intensity of the fluorescence signal of the tumor with this amount of Photofrin II was eight times lower than that obtained after an injection of 442 ng of fluorescein coupled with 20 micrograms of MoAb, which gave an absolute amount of fluorescein localized in the tumor of up to 125 ng/g of tumor. These results illustrate the possibility of improving the specificity of in vivo tumor localization of dyes for laser-induced fluorescence photodetection and phototherapy by coupling them to MoAb directed against tumor markers.

Protection against Plasmodium falciparum challenge induced in Aotus monkeys by liver-stage antigen-3-derived long synthetic peptides.

The vaccine potential of Plasmodium falciparum liver stage antigen-3 (LSA3) was investigated in Aotus monkeys using two long synthetic peptides corresponding respectively to an N-terminal non-repeat peptide (NRP) and repeat 2 (R2) region of the LSA3, adjuvanted by ASO2. Both 100-222 (NRP) and 501-596 repeat peptides induced effector B- and T-cell responses in terms of antigen-driven antibodies and/or specific IFN-gamma secretion. Animals challenged with P. falciparum sporozoites were protected following immunization with either the NRP region alone or the NRP combined with the R2 repeat region, as compared with controls receiving the adjuvant alone. These results indicate that the NRP may be sufficient to induce full, sterile protection and confirm the vaccine potential of LSA3 previously demonstrated in chimpanzees and in Aotus.