Fibrin-Associated EBV-Positive Large B-Cell Lymphoma Incidentally Found Within a Multinodular Goiter.

Fibrin-associated diffuse large B-cell lymphoma (fibrin-associated DLBCL) is a very rare subtype of Epstein-Barr virus (EBV)-associated DLBCL that usually develops within fibrin-rich lesions such as cardiac myxoma, chronic hematoma, thrombus, pseudocysts or cysts, prosthetic devices or breast implants. The pathogenesis as well as the clinicopathologic features of this usually indolent lymphoproliferative disorder, which are based on the analysis of a relatively limited number of cases, are still poorly known. Herein, we report a case of fibrin-associated DLBCL that was incidentally found within a multinodular goiter, a location not yet reported to our knowledge. Our findings not only illustrate further the specific nature of this peculiar lymphoproliferative disorder but also allow some interesting comments on its pathogenesis.

Diabetes insipidus and acute myeloid leukemia harboring monosomy 7: report of two cases and literature review.

Acute myeloid leukemia (AML) is unusually associated with diabetes insipidus (DI) in patients bearing monosomy 7 or chromosome 3 aberrations. To date, 84 cases have been reported worldwide. Physiopathological mechanisms linking these chromosomal abnormalities to DI are not yet understood. We report two patients with AML/DI and review the medical literature on those conditions.

Chromothripsis in an Early Recurrent Chordoid Meningioma.

BACKGROUND: Chromothripsis is characterized by a multitude of chromosomal rearrangements during a unique cataclysmic event in a cell life. Disintegration of one or several chromosomes is followed by a chaotic rearrangement of generated fragments. It might play a role in oncogenesis and tumor progression. It is observed in 2%-3% of cancers and is rarely reported in benign tumors. We report a case of massive chromothripsis in a fast growing chordoid meningioma. CASE DESCRIPTION: A 55-year-old woman was admitted for a meningeal mass developing in the right parietal parasagittal area. She underwent subtotal resection of the tumor. Histologic analysis revealed a chordoid meningioma (World Health Organization grade II). Six months later, magnetic resonance imaging showed a large bilateral tumor recurrence. After a second surgery, the patient received radiotherapy. Thereafter, the clinical course was uneventful. Comparative genomic hybridization showed only a monosomy X in the primary tumor. In the recurrent meningioma, this anomaly was associated with a massive chromothripsis including more than 370 chromosomal abnormalities affecting chromosomes 1-22. CONCLUSIONS: Chromothripsis is rarely described in benign tumors and especially in meningiomas. In the presented case, the high number of chromosomal rearrangements and the onset of this phenomenon at a later stage of tumor progression are very unusual. The role of surgical stress on the emergence of chromothripsis and its relation with tumor aggressiveness are discussed.

Identification by array comparative genomic hybridization of a new amplicon on chromosome 17q highly recurrent in BRCA1 mutated triple negative breast cancer.

INTRODUCTION: Triple Negative Breast Cancers (TNBC) represent about 12% to 20% of all breast cancers (BC) and have a worse outcome compared to other BC subtypes. TNBC often show a deficiency in DNA double-strand break repair mechanisms. This is generally related to the inactivation of a repair enzymatic complex involving BRCA1 caused either by genetic mutations, epigenetic modifications or by post-transcriptional regulations. The identification of new molecular biomarkers that would allow the rapid identification of BC presenting a BRCA1 deficiency could be useful to select patients who could benefit from PARP inhibitors, alkylating agents or platinum-based chemotherapy. METHODS: Genomic DNA from 131 formalin-fixed paraffin-embedded (FFPE) tumors (luminal A and B, HER2+ and triple negative BC) with known BRCA1 mutation status or unscreened for BRCA1 mutation were analysed by array Comparative Genomic Hybridization (array CGH). One highly significant and recurrent gain in the 17q25.3 genomic region was analysed by fluorescent in situ hybridization (FISH). Expression of the genes of the 17q25.3 amplicon was studied using customized Taqman low density arrays and single Taqman assays (Applied Biosystems). RESULTS: We identified by array CGH and confirmed by FISH a gain in the 17q25.3 genomic region in 90% of the BRCA1 mutated tumors. This chromosomal gain was present in only 28.6% of the BRCA1 non-mutated TNBC, 26.7% of the unscreened TNBC, 13.6% of the luminal B, 19.0% of the HER2+ and 0% of the luminal A breast cancers. The 17q25.3 gain was also detected in 50% of the TNBC with BRCA1 promoter methylation. Interestingly, BRCA1 promoter methylation was never detected in BRCA1 mutated BC. Gene expression analyses of the 17q25.3 sub-region showed a significant over-expression of 17 genes in BRCA1 mutated TNBC (n = 15) as compared to the BRCA1 non mutated TNBC (n = 13). CONCLUSIONS: In this study, we have identified by array CGH and confirmed by FISH a recurrent gain in 17q25.3 significantly associated to BRCA1 mutated TNBC. Up-regulated genes in the 17q25.3 amplicon might represent potential therapeutic targets and warrant further investigation.

Multi-factor data normalization enables the detection of copy number aberrations in amplicon sequencing data.

MOTIVATION: Because of its low cost, amplicon sequencing, also known as ultra-deep targeted sequencing, is now becoming widely used in oncology for detection of actionable mutations, i.e. mutations influencing cell sensitivity to targeted therapies. Amplicon sequencing is based on the polymerase chain reaction amplification of the regions of interest, a process that considerably distorts the information on copy numbers initially present in the tumor DNA. Therefore, additional experiments such as single nucleotide polymorphism (SNP) or comparative genomic hybridization (CGH) arrays often complement amplicon sequencing in clinics to identify copy number status of genes whose amplification or deletion has direct consequences on the efficacy of a particular cancer treatment. So far, there has been no proven method to extract the information on gene copy number aberrations based solely on amplicon sequencing. RESULTS: Here we present ONCOCNV, a method that includes a multifactor normalization and annotation technique enabling the detection of large copy number changes from amplicon sequencing data. We validated our approach on high and low amplicon density datasets and demonstrated that ONCOCNV can achieve a precision comparable with that of array CGH techniques in detecting copy number aberrations. Thus, ONCOCNV applied on amplicon sequencing data would make the use of additional array CGH or SNP array experiments unnecessary.

NDRG1 and CRK-I/II are regulators of endothelial cell migration under Intermittent Hypoxia.

Intermittent Hypoxia (IH) that develops in neovascularized solid tumours has been described to positively influence the tumour growth by modulating the behaviour of cancer cells as well as of endothelial cells. However, the molecular mechanisms regulated by IH still remain poorly understood. In this work, the effects of IH were investigated on endothelial cells by a proteomic approach. Protein abundance variations were studied using fluorescent 2D-Differential in Gel Electrophoresis (2D-DIGE). Amongst the proteins of which the abundance varied under IH, NDRG1 and CRK-I/II were identified by mass spectrometry. These proteins have already been described to influence cancer cell migration as well as the angiogenic processes in solid tumours. Since an increase in endothelial cell migration under IH was evidenced in our previous work, the involvement of NDRG1 and CRK-I/II proteins in endothelial cell migration under IH was determined by silencing the expression of both proteins using siRNA. The results revealed that NDRG1 and CRK-I/II are indeed regulators of endothelial cell migration under intermittent hypoxia: silencing of CRK-I/II resulted in an increase in endothelial cell migration, whereas the invalidation of NDRG1 decreased it. These results give news insight regarding the effects of IH on endothelial cell migration and hence on neoangiogenesis.

Intermittent hypoxia is an angiogenic inducer for endothelial cells: role of HIF-1.

The presence of hypoxia in tumor and its role in promoting angiogenesis are well-established. Recently, in addition to chronic hypoxia, cycling or intermittent hypoxia has also been demonstrated. However, its role in inducing new blood vessel formation is less clear. This work is aimed to investigate whether intermittent hypoxia can induce a pro-angiogenic phenotype in endothelial cells, in vitro. We studied changes in the expression of genes involved in inflammation and angiogenesis under intermittent and chronic hypoxia. We evidenced genes specifically expressed under intermittent hypoxia, suggesting different cell responses induced by intermittent versus chronic hypoxia. An increase in the expression of pro-angiogenic and pro-inflammatory genes under intermittent hypoxia, translating a pro-angiogenic effect of intermittent hypoxia was detected. In parallel, we investigated the activity of three transcription factors known to be activated either under hypoxia or by reoxygenation: HIF-1, Nrf2, and NF-kappaB. HIF-1alpha stabilization and an increase in HIF-1 transcriptional activity were evidenced under intermittent hypoxia. On the other hand, NRF2 and NF-kappaB transcription factors were not activated. Finally, an increase in endothelial cell migration and in tubulogenesis in the course of hypoxia-reoxygenation cycles was evidenced, which was inhibited by HIF-1alpha siRNA. All together, these results demonstrate a clear pro-angiogenic effect of intermittent hypoxia.

Hypoxia regulates inflammatory gene expression in endothelial cells.

Hypoxia can activate the endothelium toward a pro-inflammatory phenotype and enhance leukocyte adhesion. This process is involved in pathological conditions such as vascular remodeling or ischemia-reperfusion injury. This study was aimed to obtain a global picture of the response of the endothelial cells to hypoxia with respect to inflammatory genes. To this purpose, we used a low density DNA microarray specifically designed to quantitate the expression of genes involved in the inflammatory pathways and a customized real-time PCR array. The expression of several pro-inflammatory genes known to be NF-kB target genes was decreased after the incubation of endothelial cells under hypoxia. In parallel, a decrease in the DNA binding activity of this transcription factor was observed. On the other hand, HIF-1 DNA binding activity was increased as well as the expression of several genes known to be regulated by this factor. Among them are several pro-inflammatory genes whose overexpression could account for the increase in leukocyte adhesion to the hypoxic endothelial cells. We concluded that hypoxia does not shift the endothelial cell phenotype to a more pro-inflammatory one probably because of a decrease in the expression of several cytokines. On the other hand, a clear response to hypoxia was observed with HIF-1 probably playing an important role in this process.

Dual effect of echinomycin on hypoxia-inducible factor-1 activity under normoxic and hypoxic conditions.

Hypoxia-inducible factor-1 (HIF-1) is now recognized as a possible target for cancer treatment. This transcription factor is responsible for the overexpression of several genes favouring cancer cell survival and inducing neo-angiogenesis. Echinomycin has recently been described to inhibit HIF-1 DNA binding and transcriptional activity. In this work, it is shown that echinomycin strongly inhibits the activity of HIF-1 under hypoxic conditions, and also interferes with the activity of other transcription factors. These results demonstrate the lack of specificity of this molecule. Moreover, it is demonstrated that echinomycin induces an increase in HIF-1 activity under normoxic conditions, parallel to an increase in the expression of HIF-1 target genes. This effect is caused by an increase in HIF-1alpha protein level, resulting from an increase in the transcription of the HIF-1A gene in the presence of a low concentration of echinomycin. Transfection experiments with HIF-1alpha promoter constructs revealed the presence of an Sp1 binding element responsive to echinomycin. Furthermore, echinomycin enhanced Sp1 activity, as measured by the use of a specific reporter system. These findings show, for the first time, that echinomycin has a dual effect on HIF-1 activity under normoxic and hypoxic conditions, demonstrating that this molecule cannot be used in cancer treatment.

Intermittent hypoxia changes HIF-1alpha phosphorylation pattern in endothelial cells: unravelling of a new PKA-dependent regulation of HIF-1alpha.

Vascularized tumors are exposed to intermittent hypoxia, that is, hypoxia followed by periods of reoxygenation. Abnormal structure and dysfunction of tumor blood vessels are responsible for these conditions. These repeated short periods of hypoxia concern tumor cells as well as endothelial cells. However, the effects of intermittent hypoxia are poorly understood. The aim of this study was to investigate the effects of intermittent hypoxia on endothelial cells and particularly on HIF-1alpha, a central actor in adaptive response to hypoxia. For that, endothelial cells were exposed to four repeated cycles of 1-h hypoxia followed by 30 min of reoxygenation. We showed that repeated cycles of hypoxia/reoxygenation induced a modification in HIF-l alpha phosphorylation pattern: a progressive increase in HIF-1alpha phosphorylated form was observed during the hypoxic periods. Activation of p42/p44, Akt and PKA was observed in parallel. PKA was shown to be involved in the phosphorylation of HIF-lalpha under intermittent hypoxia, while p42/p44 and Akt were not. As HIF-1 activity is often associated with enhanced cell survival, a better knowledge of the effects of intermittent hypoxia on endothelial cells and the highlight of particular mechanisms induced by intermittent hypoxia are essential to understand the behavior of endothelial cells during neo-angiogenesis.

Hypoxia and CoCl2 protect HepG2 cells against serum deprivation- and t-BHP-induced apoptosis: a possible anti-apoptotic role for HIF-1.

Hypoxia inducible factor-1 (HIF-1) is the main transcriptional factor activated by hypoxia. Besides the well-described role assigned to HIF-1 in the adaptation of cells to hypoxia, different recent data describe a possible role for HIF-1 in the modulation of apoptosis. However, this precise role is not yet clearly understood. In this study, chemical and physiological hypoxia, which were shown to induce HIF-1alpha stabilization and HIF-1 activation, were shown to inhibit apoptosis induced in HepG2 cells by two different pro-apoptotic conditions, serum deprivation- and t-BHP-induced oxidative stress. Indeed, hypoxia reduced DNA fragmentation, caspase activation, and PARP cleavage induced by these two pro-apoptotic conditions. These results are very interesting because it is a clear demonstration that hypoxia and chemical hypoxia have a direct protective effect on apoptotic cell death induced by two different stimuli. This observation is an important data in understanding how tumor growth can occur in challenging environmental conditions.