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As a major cancer hallmark, there is a sustained interest in understanding the telomerase contribution to carcinogenesis in order to therapeutically target this enzyme. This is particularly relevant in primary cutaneous T-cell lymphomas (CTCL), a malignancy showing telomerase dysregulation with few investigative data available. In CTCL, we examined the mechanisms involved in telomerase transcriptional activation and activity regulation. We analyzed 94 CTCL patients from a Franco-Portuguese cohort, as well as 8 cell lines, in comparison to 101 healthy controls. Our results showed that not only polymorphisms (SNPs) located at the promoter of human telomerase reverse transcriptase (hTERT) gene (rs2735940 and rs2853672) but also an SNP located within the coding region (rs2853676) could influence CTCL occurrence. Furthermore, our results sustained that the post-transcriptional regulation of hTERT contributes to CTCL lymphomagenesis. Indeed, CTCL cells present a different pattern of hTERT spliced transcripts distribution from the controls, mostly marked by an increase in the hTERT β+ variants proportion. This increase seems to be associated with CTCL development and progression. Through hTERT splicing transcriptome modulation with shRNAs, we observed that the decrease in the α-β+ transcript induced a decrease in the cell proliferation and tumorigenic capacities of T-MF cells in vitro. Taken together, our data highlight the major role of post-transcriptional mechanisms regulating telomerase non canonical functions in CTCL and suggest a new potential role for the α-β+ hTERT transcript variant.

Telomeric Repeat-containing RNA (TERRA) are long non-coding RNAs transcribed from telomeric DNA sequences from multiple chromosome ends. Major research efforts have been made to understand TERRA roles and functions in several physiological and pathological processes. We summarize herein available data regarding TERRA’s roles in human cells and we report the first investigation in cutaneous T-cells lymphomas (CTCL) using real-time PCR. Among the TERRA analysed, our data suggest a particular role for TERRA 16p downregulation and TERRA 11q upregulation in CTCL lymphomagenesis.

International audience; Current multiagent chemotherapy regimens have improved the cure rate in acute leukemia patients, but they are highly toxic and poorly efficient in relapsed patients. To improve the treatment approaches, new specific molecules are needed. The G-quadruplexes (G4s), which are noncanonical nucleic acid structures found in specific guanine-rich DNA or RNA, are involved in many cellular events, including control of gene expression. G4s are considered as targets for the development of anticancer agents. Heterocyclic molecules are well known to target and stabilize G4 structures. Thus, a new series of 2,9-bis[(substituted-aminomethyl)phenyl]-1,10-phenanthroline derivatives (1a-i) was designed, synthesized, and evaluated against five human myeloid leukemia cell lines (K562, KU812, MV4-11, HL60, and U937). Their ability to stabilize various oncogene promoter G4 structures (c-MYC, BCL-2, and K-RAS) as well as the telomeric G4 was also determined through the fluorescence resonance energy transfer melting assay and native mass spectrometry. In addition, the more bioactive ligands 1g-i were tested for telomerase activity in HuT78 and MV4-11 protein extracts.

Cutaneous T-cell lymphomas (CTCLs) are telomerase-positive tumors expressing hTERT, although neither gene rearrangement/amplification nor promoter hotspot mutations could explain the hTERT re-expression. As the hTERT promoter is rich in CpG, we investigated the contribution of epigenetic mechanisms in its re-expression. We analyzed hTERT promoter methylation status in CTCL cells compared with healthy cells. Gene-specific methylation analyses revealed a common methylation pattern exclusively in tumor cells. This methylation pattern encompassed a hypermethylated distal region from -650 to -150 bp and a hypomethylated proximal region from -150 to +150 bp. Interestingly, the hypermethylated region matches with the recently named TERT hypermethylated oncogenic region (THOR). THOR has been associated with telomerase reactivation in many cancers, but it has so far not been reported in cutaneous lymphomas. Additionally, we assessed the effect of THOR on two histone deacetylase inhibitors (HDACi), romidepsin and vorinostat, both approved for CTCL treatment and a DNA methyltransferase inhibitor (DNMTi) 5-azacytidine, unapproved for CTCL. Contrary to our expectations, the findings reported herein revealed that THOR methylation is relatively stable under these epigenetic drugs' pressure, whereas these drugs reduced the hTERT gene expression.

Telomere erosion may be counteracted by telomerase. Here we explored telomere length (TL) and telomerase activity (TA) in primary cutaneous T-cell lymphoma (CTCL) by using quantitative polymerase chain reaction and interphase quantitative fluorescence in situ hybridization assays. Samples from patients with Sézary syndrome (SS), transformed mycosis fungoides (T-MF), and cutaneous anaplastic large cell lymphoma were studied in parallel with corresponding cell lines to evaluate the relevance of TL and TA as target candidates for diagnostic and therapeutic purposes. Compared with controls, short telomeres were observed in aggressive CTCL subtypes such as SS and T-MF and were restricted to neoplastic cells in SS. While no genomic alteration of the hTERT (human telomerase catalytic subunit) locus was observed in patients' tumor cells, TA was detected. To understand the role of telomerase in CTCL, we manipulated its expression in CTCL cell lines. Telomerase inhibition rapidly impeded in vitro cell proliferation and led to cell death, while telomerase overexpression stimulated in vitro proliferation and clonogenicity properties and favored tumor development in immunodeficient mice. Our data indicate that, besides maintenance of TL, telomerase exerts additional functions in CTCL. Therefore, targeting these functions might represent an attractive therapeutic strategy, especially in aggressive CTCL.

The World Health Organization-European Organization for Research and Treatment of Cancer has individualized three main categories among the primary cutaneous B cell lymphoma (PCBCL): leg-type primary cutaneous large B cell lymphoma (PCLBCL leg type), primary cutaneous follicle center lymphoma (PCFCL), and primary cutaneous marginal zone lymphoma (PCMZL). The genetic features of 21 PCBCL cases (six PCLBCL leg type four PCFCL large cells, seven PCFCL small cells, and four PCMZL) were investigated by comparative genomic hybridization (CGH array). Fluorescent in situ hybridization (FISH) analysis was performed to confirm CGH array data and to detect lymphoma-associated gene rearrangements. p14(ARF)/p16(INK4a) CDKN2A gene quantification, methylation analysis, and immunohistochemical detection were also performed. CGH array showed a higher number of recurrent genetic imbalances in PCLBCL leg type (mean 62) than in PCFCL large cells (mean 34). PCFCL small cells and PCMZL exhibited fewer chromosomal alterations (mean 24 and 9). FISH analysis provided concordant results with CGH array data in 97% (98 of 101) assays and demonstrated a t(8;14)(q24;q32) in two of six PCLBCL leg type. Recurrent deletions in 9p21 (p14(ARF)/p16(INK4a)CDKN2A) were a constant finding in PCLBCL leg type (six of six). Conversely, PCFCL large cells exhibited recurrent 1p36 deletions (four of four) without deletion in 9p21 (zero of four). The diagnostic and prognostic impact of the p16(INK4a)CDKN2A gene status in PCBCL should therefore be confirmed on a larger series.

Primary cutaneous CD30+ large T-cell lymphoma (CD30+ CTCL) is a subset of non-epidermotropic primary cutaneous T-cell lymphoma. Although frequent spontaneous regression may be observed, skin relapses occur frequently. Cytogenetic abnormalities that could play a role in CD30+ CTCL tumour pathogenesis and relapses remain unknown. The identification of recurrent cytogenetic abnormalities is hampered by difficulty in culturing tumours and the lack of CD30+ CTCL serial studies comparing genetic changes both at diagnosis and at relapse. The purpose of this study was to investigate the cytogenetic abnormalities present in a series of 13 CD30+ CTCL samples obtained from nine patients fulfilling both EORTC and WHO diagnostic criteria, by the use of comparative genomic hybridization (CGH). CGH analysis revealed a non-random distribution of genetic imbalances between relapsing and non-relapsing disease. In relapsing disease, chromosomal abnormalities were detected both in the primary tumour and in relapses. The mean number of changes in non-relapsing disease was 0.33 (range 0-1), compared with 6.29 (range 1-16) in relapsing disease. The recurrent chromosomes involved in relapsing disease were chromosomes 6 (86%), 9 (86%), and 18 (43%). While chromosome 9 was mostly affected by gain, chromosomes 6 and 18 mainly contained regions of loss, exclusively on 6q and 18p. The common regions of deletion were 6q21 and 18p11.3. In one patient, we successfully cultured tumour cells from a skin biopsy from a second relapse. The G-banded karyotype was concordant with both CGH and fluorescence in situ hybridization (FISH) results. Although further studies are required to strengthen these data, this CGH analysis demonstrates chromosomal imbalances that may be involved in the pathogenesis of relapsing CD30+ CTCL.

The t(12;15)(p13;q25) translocation, a recurrent chromosomal abnormality of congenital fibrosarcoma, leads to the expression of a Tel–TrkC fusion transcript. To determine whether detection of the chimeric protein may be helpful for the diagnosis of congenital fibrosarcoma, immunohistochemistry was performed with an anti-TrkC antibody on 26 spindle cell tumours of newborn or young children (n=19) or adults (n=7). Four out of five congenital fibrosarcomas showed TrkC immunoreactivity with cytoplasmic paranuclear staining. However, TrkC immunoreactivity was not restricted to congenital fibrosarcoma and was observed in infantile myofibromatosis, congenital haemangiopericytoma, desmoid tumour, nodular fasciitis, fibrous hamartoma, inflammatory myofibroblastic tumour, and adult fibrosarcoma. RT-PCR analysis was performed on nine cases, including four congenital fibrosarcomas, for which frozen material was available. Tel–TrkC transcripts were detected by RT-PCR in the four congenital fibrosarcomas analysed, but not in the five other spindle cell tumours. Furthermore, several Tel–TrkC transcripts encoding for kinase isoforms of the Tel–TrkC protein were detected in congenital fibrosarcoma and may be involved in oncogenesis. The reciprocal TrkC–Tel transcript was detected in only one congenital fibrosarcoma. While the detection of a Tel–TrkC fusion transcript is a recurrent feature of congenital fibrosarcoma, TrkC immunoreactivity does not appear specific for the diagnosis of fibromatous paediatric tumours. Copyright © 2000 John Wiley & Sons, Ltd.

Objectives Recent studies have shown that telomere length was significantly reduced in placentas collected at delivery from pregnancies complicated by intrauterine growth restriction secondary to placental insufficiency. Placental telomere length measurement during ongoing pregnancies complicated by intrauterine growth restriction has never been reported. This was the main objective of our study. Methods In our center, late chorionic villus samplings were performed between 18 and 37 weeks of amenorrhea in 24 subjects with severe intrauterine growth restriction (cases) and in 28 subjects with other indications for prenatal diagnosis (controls). Placental insufficiency was assessed by histo-pathological examination. Relative measurement of telomere length was carried out prospectively by quantitative Fluorescent In Situ Hybridization using fluorescent Peptide Nucleic Acid probes on interphase nuclei obtained from long-term cultured villi and with an automated epifluorescent microscope. A quantitative Polymerase Chain Reaction technique was performed to confirm the quantitative Fluorescent In Situ Hybridization results. The number of copies of gene loci encoding the RNA template (hTERC) and the catalytic subunit (hTERT) of the enzyme complex telomerase were also estimated in these placentas by Fluorescent In Situ Hybridization. Results Mean fluorescence intensity of telomere probes estimated by quantitative Fluorescent In Situ Hybridization was significantly less for cases compared to controls (p

Dans 70 a 90 % des cellules tumorales humaines, une activite telomerase est detectee alors que dans les tissus avoisinants non tumoraux, l’activite de la telomerase est faible voire nulle. La telomerase et la longueur des telomeres ont ete proposees comme des biomarqueurs des cellules tumorales. Ces biomarqueurs ont ete etudiee dans les tumeurs solides [1] et hematologiques [2] . En revanche dans les lymphomes T cutanes primitifs (LTCP) les donnees sont rares. Dans une premiere etude [3] , nous avons evalue l’impact de la longueur des telomeres et de l’activite de la telomerase dans la lymphomagenese des LTCP. Nous avons montre que les LTCP agressifs possedaient des telomeres courts par rapport aux LTCP indolents et aux cellules saines, que dans les cellules de LTCP une activite telomerase etait presente, faisant de ces tumeurs des candidates potentielles a un traitement cible anti-telomerase. Pour mieux comprendre la fonction de la telomerase dans ces cellules, nous avons module l’expression de la telomerase, via sa sous-unite catalytique hTERT, a l’aide de constructions lentivirales dans des lignees cellulaires de LTCP. Nous avons montre que l’inhibition de la telomerase se traduisait par une diminution brutale de la proliferation cellulaire et conduisait a la mort cellulaire. En revanche, la surexpression de la telomerase est associee a une augmentation de la proliferation cellulaire, a une augmentation des capacites clonogene et tumorigene des cellules infectees aussi bien in vitro (test de soft agar) que in vivo (xenogreffe chez la souris). Ces dernieres observations laissent supposer qu’au-dela de son role de maintenance des telomeres dans les cellules de LTCP, la telomerase exerce d’autres fonctions, qualifiees de non-canoniques, car independantes de ses fonctions sur les telomeres. La connaissance de ses fonctions est indispensable avant d’envisager d’utiliser la telomerase comme cible therapeutique dans les LTCP.

Benign lymphocytic angiitis and granulomatosis is a T-cell lymphoproliferative disorder confined to the lung and corresponding to a low-grade angiocentric immunoproliferative lesion. Controversy remains as to whether these lesions are lymphomas. We report such a case in an 8-year-old patient with Burkitt's lymphoma in remission who presented with persistent bronchopneumopathy and bilateral pulmonary infiltrates on tomodensitometry. Surgical resection revealed the histologic changes of benign lymphocylic angiitis and granulomatosis. Immunohistochemistry showed no aberrant pan T-cell marker loss. Genetic analysis of frozen tissue by Southern blot DNA hybridization with probes to T-cell receptor beta- and gamma-chain genes and to the immunoglobulin heavy chain joining region gene (JH) identified no clonal rearrangement. Search for Epstein-Barr virus-DNA sequences by in situ hybridization and Southern blot analysis provided negative results. Our data imply that low-grade angiocentric immunoproliferative lesions are not exclusively lymphomas but might represent a borderline lymphoproliferative disease (seen in the course of many diseases), perhaps corresponding to host immune response.

Congenital mesoblastic nephroma (CMN) is a rare renal tumor of early infancy with a favorable outcome after complete surgical removal. CMN consists of a heterogeneous group of spindle cell tumors subdivided into "classical", "cellular or atypical" and "mixed" forms based on histologic features. We describe a new case of cellular CMN diagnosed by antenatal ultrasonography with complete remission five years after nephrectomy. Cytogenetic study evidenced a trisomy 11, and real time RT-PCR, but not conventional karyotype, allowed for the detection of the Tel-ETV6/TrkC-NTRK3 fusion transcript as a consequence of a cryptic t(12-15)(p13;q25). As in congenital fibrosarcoma (CFS), two Tel-ETV6/ TrkC-NTRK3 fusion transcripts different by a 42 bp insert in the TrkC kinase domain were expressed. Our observations outline the close links between cellular CMN and CFS. Both tumors have the clinical presentation and histologic features as well as identical cytogenetic and molecular markers in common. Therefore, they are likely to represent the same neoplasm, but occurring at different locations.

This study was undertaken to determine the prognostic value of bone marrow histopathologic and molecular analyses in 53 patients with mycosis fungoides and 7 with Sezary syndrome. Bone marrow was involved in only 1 patient with Sezary syndrome, clinical stage IVA, before bone marrow biopsy. An ambiguous T-cell infiltrate was observed in 8 patients but was not associated with disease progression. The bone marrow specimen was normal in 51 patients. Monoclonality was detected in the skin specimen in 44 cases; an identical T-cell clone in the blood specimen was found in 21 of them and, in 16 of the 21 patients, in bone marrow specimens without histologic correlation. Multivariate analysis confirmed that clinical stage and detection by polymerase chain reaction of an identical T-cell clone in skin and blood specimens had an independent prognostic value. No further prognostic value was observed for the presence of a T-cell clone in bone marrow specimens. Our data do not support the need for bone marrow examination in patients with mycosis fungoides/Sezary syndrome.

By prospectively studying immunoglobulin heavy chain gene (IgH) and T cell receptor gamma (TCRγ) gene rearrangements in 398 lymphoma cases, a dual genotype was observed in 13% of B cell and 11% of T cell lymphomas. According to histological subtype, the highest incidence was observed for mantle cell lymphomas (32%) and lymphoplasmacytic lymphoma (21%) among B cell lymphomas, and for angioimmunoblastic lymphoma (AILT) (46%) and Sezary syndrome (SS) (50%) among T cell lymphomas. To determine whether the dual genotype corresponds to the presence of two distinct monoclonal populations or to the presence of both rearrangements within the same lymphoma cells, single-cell microdissection was used after immunohistochemistry and a single-cell combined IgH and TCRγ gene analysis was designed after a whole-genome amplification step. This protocol was applied to the study of two nodal B cell lymphomas (one diffuse large B cell lymphoma and one mantle cell lymphoma) and two cutaneous T cell lymphomas (one AILT and one SS). Two cases (SS and mantle cell lymphoma) were true bigenotypic lymphomas, as both IgH and TCRγ monoclonal rearrangements were detected in the same cells. Conversely, in the diffuse large B cell lymphoma and AILT cases, large CD22+ single cells exhibited only the monoclonal IgH rearrangement but not the TCRγ gene that was detected in CD3+ single cells. Such an approach allows the identification of true bigenotypic lymphoma among dual genotypic lymphoma. Specific genetic alterations may be further amplified from microdissected cryopreserved material, such as the t(11;14) breakpoint detected in bigenotypic B cells of the mantle cell lymphoma case. Copyright © 2002 John Wiley & Sons, Ltd.

The expression of neurotrophins and their receptors, the low-affinity nerve growth factor receptor (p75 LNGFR ) and the Trk receptors (TrkA, TrkB, and TrkC), was investigated in human bone marrow from 16 weeks fetal age to adulthood. Using reverse transcription-polymerase chain reaction, all transcripts encoding for catalytic and truncated human TrkB or TrkC receptors were detected together with trk AI transcripts, whereas trk AII transcripts were found only in control nerve tissues. Transcripts for the homologue of the rat truncated TrkC(ic113) receptor were identified for the first time in human tissue. Stromal adventitial reticular cells were found immunoreactive for all neutrophin receptors. In contrast, hematopoietic cell types were not immunoreactive for p75 LNGFR but showed immunoreactivity for one or several Trk receptors. TrkA immunoreactivity was found in immature erythroblasts. Catalytic TrkB immunoreactivity was observed in eosinophilic metamyelocytes and polymorphonuclear cells. Truncated TrkB immunoreactivity was found in erythroblasts and megacaryocytes. Immunoreactivity for both catalytic and truncated TrkC receptor was observed in promyelocytes, myelocytes, some polymorphonuclear cells and megacaryocytes. Neutrophin transcript levels appeared higher at fetal than at adult stages, no variation in Trk family transcript levels was observed. The local expression of neurotrophin genes suggests a wide range of paracrine and/or autocrine mode of action through their corresponding receptors within the bone marrow.