“Stealth” tumors: Breast cancer cells shun NK-cells anti-tumor immunity

Breast cancers (BCs) comprise heterogeneous subtypes of various prognoses. An active anti-tumor immune profile usually correlated with a better survival. Two current major challenges of BC research are to understand the inter-relations between BC and anti-tumor immunity, and to identify candidates whose targeting would contribute to enhance anti-tumor efficiency

CpG-ODN-induced sustained expression of BTLA mediating selective inhibition of human B cells

BTLA (B- and T-lymphocyte attenuator) is a prominent co-receptor that is structurally and functionally related to CTLA-4 and PD-1. In T cells, BTLA inhibits TCR-mediated activation. In B cells, roles and functions of BTLA are still poorly understood and have never been studied in the context of B cells activated by CpG via TLR9. In this study, we evaluated the expression of BTLA depending on activation and differentiation of human B cell subsets in peripheral blood and lymph nodes. Stimulation with CpG upregulated BTLA, but not its ligand: herpes virus entry mediator (HVEM), on B cells in vitro and sustained its expression in vivo in melanoma patients after vaccination. Upon ligation with HVEM, BTLA inhibited CpG-mediated B cell functions (proliferation, cytokine production, and upregulation of co-stimulatory molecules), which was reversed by blocking BTLA/HVEM interactions. Interestingly, chemokine secretion (IL-8 and MIP1β) was not affected by BTLA/HVEM ligation, suggesting that BTLA-mediated inhibition is selective for some but not all B cell functions. We conclude that BTLA is an important immune checkpoint for B cells, as similarly known for T cell

Contiguous follicular lymphoma and follicular lymphoma in situ harboring N-glycosylated sites

International audienceFollicular lymphoma in situ (FLIS) is composed of a clonal B-cell population harboring the typical t(14;18) hallmark of follicular lymphoma (FL), forming unconventional BCL2 Bright CD10 + cell foci in an otherwise normal reactive lymph node (LN). The diagnosis of FLIS is made on the fortuitous discovery of unconventional BCL2 Bright CD10 + cell foci. 1 Several studies recently demonstrated that FLIS are already advanced precursors in follicular lymphomagene-sis, but not necessarily committed to malignant transformation. 2,3 However, the relationship between FLIS and FL still remains unclear, as only a minority (<5%) of FLIS patients eventually develop FL. This is in line with the usually indolent progression of the disease, and the genomic instability observed in FLIS cells, which can engage FL precursor cells either in an evolutionary malignant process, or to an evolutionary dead end. 4 We report the case of a 35-year old male patient who presented with a cervical adenopathy. Histological examination of the excised LN displayed an altered architecture suggestive of FL, consisting of high number of monomorphic large follicles, uniformly spread in the cortical and medullary areas. Most follicles contained a predominant population of small cleaved cells with scant macrophages and mitoses. The mantle zone was reduced or absent. However, in a minor cortical area, a few follicles showed features mimicking residual classical germ cells (GC), including a smaller size, higher cell polymorphism, and a preserved mantle zone (Figure 1A). The BCL2 immunostaining (clone 100) was negative in follicles displaying a typical FL pattern. In contrast, follicles located in the pseudo-residual area were BCL2bright, i.e. more strongly stained than the surrounding mantle zone and reactive T cells (Figure 1B). Most follicles were only slightly positive for Ki67 (Online Supplementary Figure S1A). Both BCL2 – and BCL2 + follicles were CD10 positive (Online Supplementary Figure S1B) and contained a BCL2/JH break-point evidenced by fluorescence in situ hybridization (FISH) (Figure 1C). Taken together these results suggested the diagnosis of simultaneous occurrence of BCL2 – FL (grade I/II) and of BCL2 + FLIS in the same LN. We decided to further analyze those two lesions independently, and performed macrodissection in order to proceed with individual molecular analyses when required. Sanger sequenc-ing revealed that both FLIS and FL shared the same BCL2/JH sequence at the t(14;18)+ breakpoint, and thus originated from the same clone (Figure 1D). We tested two other anti-BCL2 antibodies (E17, SP66) directed against other epitopes, but the staining remained BCL2-in the FL area of the LN, similar to the anti-BCL2 antibody (clone 100) staining (Figure 1E and F). We thus sequenced exons 1 to 3 of the BCL2 gene (B-cell CLL/lym-phoma 2, NG_009361.1). Punctual mutations, resulting in amino acid substitutions, were found in the FL component (Online Supplementary Table S1), and were indeed located in the targeted aa41 to aa54 epitope of clone 100 (mutation

Kinome expression profiling and prognosis of basal breast cancers

<p>Abstract</p> <p>Background</p> <p>Basal breast cancers (BCs) represent ~15% of BCs. Although overall poor, prognosis is heterogeneous. Identification of good- <it>versus </it>poor-prognosis patients is difficult or impossible using the standard histoclinical features and the recently defined prognostic gene expression signatures (GES). Kinases are often activated or overexpressed in cancers, and constitute targets for successful therapies. We sought to define a prognostic model of basal BCs based on kinome expression profiling.</p> <p>Methods</p> <p>DNA microarray-based gene expression and histoclinical data of 2515 early BCs from thirteen datasets were collected. We searched for a kinome-based GES associated with disease-free survival (DFS) in basal BCs of the learning set using a metagene-based approach. The signature was then tested in basal tumors of the independent validation set.</p> <p>Results</p> <p>A total of 591 samples were basal. We identified a 28-kinase metagene associated with DFS in the learning set (N = 73). This metagene was associated with immune response and particularly cytotoxic T-cell response. On multivariate analysis, a metagene-based predictor outperformed the classical prognostic factors, both in the learning and the validation (N = 518) sets, independently of the lymphocyte infiltrate. In the validation set, patients whose tumors overexpressed the metagene had a 78% 5-year DFS <it>versus </it>54% for other patients (p = 1.62E-4, log-rank test).</p> <p>Conclusions</p> <p>Based on kinome expression, we identified a predictor that separated basal BCs into two subgroups of different prognosis. Tumors associated with higher activation of cytotoxic tumor-infiltrative lymphocytes harbored a better prognosis. Such classification should help tailor the treatment and develop new therapies based on immune response manipulation.</p

Whole-genome/exome analysis of circulating tumor DNA and comparison to tumor genomics from patients with heavily pre-treated ovarian cancer: subset analysis of the PERMED-01 trial

IntroductionThe poor prognosis of ovarian carcinoma (OvC) is due to the advanced stage at diagnosis, a high risk of relapse after first-line therapies, and the lack of efficient treatments in the recurrence setting. Circulating tumor DNA (ctDNA) analysis is a promising tool to assess treatment-resistant OvC and may avoid iterative tissue biopsies. We aimed to evaluate the genomic profile of recurrent heavily pre-treated OvC.MethodsWe performed tumor panel-based sequencing as well as low-coverage whole-genome sequencing (LC-WGS) of tumor and plasma collected in patients with ovarian cancer included in the PERMED-01 trial. Whole-exome sequencing (WES) data of plasma samples were also analyzed and compared to mutation and copy number alteration (CNA) tumor profiles. The prognostic value [progression-free survival (PFS)] of these alterations was assessed in an exploratory analysis.ResultsTumor and plasma genomic analyses were done for 24 patients with heavily pretreated OvC [67% high-grade serous carcinoma (HGSC)]. Tumor mutation burden was low (median 2.04 mutations/Mb) and the most frequent mutated gene was TP53 (94% of HGSC). Tumor CNAs were frequent with a median of 50% of genome altered fraction. Plasma LC-WGS and WES detected ctDNA in 21/24 cases (88%) with a median tumor fraction of 12.7%. We observed a low correlation between plasma and tumor CNA profiles. However, this correlation was significant in cases with the highest circulating tumor fraction. Plasma genome altered fraction and plasma mutation burden (p = 0.011 and p = 0.041, respectively, log-rank tests) were associated with PFS.ConclusionsCombination of LC-WGS and WES can detect ctDNA in most pre-treated OvCs. Some ctDNA characteristics, such as genome altered fraction and plasma mutation burden, showed prognostic value. ctDNA assessment with LC-WGS may be a promising and non-expansive tool to evaluate disease evolution in this disease with high genomic instability.Clinical Trial Registrationhttps://clinicaltrials.gov/ct2/show/NCT02342158, identifier NCT02342158

Etude des mécanismes immunologiques impliqués dans la perte de contrôle de l'inflammation au cours des exacerbations de l'asthme sévère (données de l'étude ISEA, Induced Sputum In Exacerbation of Asthma)

La prévalence des pathologies atopiques est en constante augmentation dans tous les pays industrialisés. Ces maladies occupent aujourd'hui la quatrième place des maladies mondialement recensées par l'OMS. D'un point de vue immunopathologique, les études réalisées au cours de ces 20 dernières années ont montré que les maladies atopiques impliquaient une activation des lymphocytes Th2, synthétisant de l'IL-4, IL-5 et IL-13. Ces cytokines sont responsables de l'activation et du recrutement d'autres cellules inflammatoires, notamment les éosinophiles, et de la libération de médiateurs de l'inflammation responsables de la contraction des muscles bronchiques, de la destruction des tissus environnants et de la sécrétion de mucus, caractéristiques des symptômes allergiques. Pourtant plusieurs travaux suggèrent que cette inflammation, pertinente pour l'atopie et la présence des éosinophiles dans les tissus atteints, est insuffisante pour expliquer l'asthme. C'est cette problématique qui a orienté les recherches menées au cours de ma thèse. Ainsi, nous avons montré, dans l'asthme, qu'à l'inflammation chronique de type Th2, était associée une inflammation aiguë Th1 avec production d'IFN- . Par ailleurs il a récemment été montré que des lymphocytes T dits régulateurs (Treg), producteurs d'IL-10 et/ou de TGF- et inducteurs de tolérance étaient déficitaires chez les sujets allergiques. Nous avons effectivement mis en évidence une diminution de cette population chez l'asthmatique en crise, et émis l'hypothèse que leur diminution pourrait rendre compte de l'activation chronique Th2 rencontrée chez l'atopique, et de l'augmentation Th1 aiguë chez l'asthmatique. Le second projet a porté sur l'étude de l'inflammation bronchique et périphérique au cours du rejet chronique de greffe, la bronchiolite oblitérante (BO), qui est actuellement la principale complication à long terme de survie du patient. Grâce au suivi des patients par expectoration induite, nous avons pu mettre en évidence que le poumon greffé était le site d'un phénomène inflammatoire qui persistait tout au long de la vie du receveur, même en l'absence de phénomène de rejet ou d'infection, et que la BO était associée à une augmentation de la proportion des éosinophiles bronchiques. Nous avons ensuite investigué l'inflammation lymphocytaire T bronchique et périphérique au cours des différents stades d'évolution de la BO et établi un profil Th1/Th2 mixte chez les BO de mauvais pronostic tandis que les BO stables présentent un biais Th2. En revanche, le fait de développer une BO, quelque soit le stade évolutif concerné, est associé à une augmentation très importante des populations T régulatrices et de leurs cytokines respectives, suggérant que la BO pourrait être due à un excès de tolérance plutôt qu'à un véritable rejet du greffon.AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

The emerging role of the TGFβ tumor suppressor pathway in pancreatic cancer

International audienc

When breast cancer cells start to fend the educational process of NK cells off

International audienceThe notion of natural killer (NK)-cell education has recently emerged, and accumulating evidence indicates that the terminal differentiation of NK cells can be achieved in the periphery. This means that the proper function of these lymphocytes is dependent on their environment, opening a new door through which cancer cells can escape immunosurveillance

Les granules de stress, des acteurs émergents en cancérologie

International audienceCancer cells are submitted to numerous stresses during tumor development, such as hypoxia, lack of nutrient, oxidative stress, or mechanical constriction. A complex mechanism termed the integrated stress response (ISR) occurs allowing cell survival. This mechanism leads to the formation of membraneless cytoplasmic structures called stress granules. The hypothesis that these structures play a major role during tumorigenesis has recently emerged. Here, we describe the biological function of stress granules and of proteins that their formation. We also present the current evidences for their involvement in the development of tumors and in the tumor resistance to cancer drugs. Finally, we discuss the interest of targeting stress granule formation to enhance treatment efficiency in order to delay tumor progression.Les stress induits au sein des tumeurs en cours de développement (hypoxie, stress oxydant, etc.) sont connus depuis de nombreuses années. Cependant, l’implication de la réponse au stress dans le processus tumoral est un concept récent. Les granules de stress (GS) sont des structures cytoplasmiques qui se forment à la suite d’une exposition à un stress et qui ont des effets cytoprotecteurs. De nombreuses données sont en faveur de l’implication de ces granules dans l’évolution tumorale et métastatique, mais aussi dans le développement de la chimiorésistance des tumeurs. Nous abordons dans cet article le rôle particulier des granules de stress en cancérologie et, plus spécifiquement, celui des protéines qui contrôlent leur formation