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L Xerri

Publications and source records attributed to L Xerri.

At least 55 records · Page 3Linked to original sources

[Use of high-density filters ("DNA arrays") for gene expression analysis in human tissues].

Most technical strategies for the analysis of gene expression in tissues are able to study only one protein or RNA product at the same time. A new recent method referred to as < > or < > is able to analyze simultaneously several hundreds of different genes. The DNA array is a nylon membrane on which are spotted equal amounts of cDNAs corresponding to different genes. This filter is hybridized with a < > probe synthesized with mRNA derived from the tissue analyzed. The result gives a global profile of gene expression within the tissue and allows quantitative and comparative analysis between different tissues or cell types.

DNA, Complementary↗

Prognostic significance of T-cell phenotype in aggressive non-Hodgkin's lymphomas. Groupe d'Etudes des Lymphomes de l'Adulte (GELA).

Peripheral T-cell lymphomas (PTCL) have been generally reported to have a worse prognosis than B-cell lymphomas (BCL). Because of their heterogeneity and scarcity, the outcomes of the different histological subtypes have not been compared. From October 1987 to March 1993, 1,883 patients with diffuse aggressive non-Hodgkin's lymphomas (NHL) included in the LNH87 protocol could be assessed for both morphology and immunophenotyping. Among them, 288 (15%) had PTCL and 1,595 (85%) had BCL. According to the Kiel classification, most PTCL were classified as angioimmunoblastic (AIL; 23%), pleomorphic medium and large T-cell (PML; 49%), or anaplastic large cell (ALCL; 20%) lymphomas. Comparing PTCL with BCL patients, the former had more disseminated disease (78% v 58%), B symptoms (57% v 40%), bone marrow involvement (31% v 17%), skin involvement (21% v 4%), and increased beta2-microglobulin (50% v 34%), whereas BCL patients had more bulky disease (41% v 26%). According to the International Prognostic Index (IPI), PTCL and BCL scores were, respectively: 0 factors, 13% and 15%; 1 factor, 17% and 22%; 2 factors, 24% and 25%; >/=3 factors, 45% and 37% (P = .09). For BCL and PTCL, respectively, complete remission rates were 63% and 54% (P = .004); the 5-year overall survival (OS) rates were 53% and 41% (P = .0004) and event-free survival (EFS) rates were 42% and 33% (P < . 0001). Comparison of the different histological subtypes of lymphoma showed that the 5-year OS rate for T-ALCL (64%) was superior to those of other PTCL (35%) as well as diffuse large B-cell (53%) NHL. When multivariate analysis was applied using the IPI score as one factor, nonanaplastic PTCL remained an independent parameter (P = . 0004). Although the poor prognosis of non-ALCL PTCL could be due in part to the presence of adverse prognostic factors at diagnosis, this study shows that the T-cell phenotype is an independent significant factor, which should be incorporated into the definition of prognostic groups.

Adolescent↗

Analysis of BAX expression in human tissues using the anti-BAX, 4F11 monoclonal antibody on paraffin sections.

BAX, a heterodimer partner of BCL-2, is an apoptosis inducer. We aimed to characterize the distribution of the BAX protein in normal adult human tissues using immunohistochemistry (IHC). The monoclonal antibody anti-BAX 4F11 was used on paraffin sections: immunodetection of BCL-2 was performed simultaneously on serial sections. The specificity of BAX IHC staining was verified by Western blot analysis. IHC positivity was correlated with the detection of a specific 21 kDa band on Western blots. BAX immunostaining was mainly cytosolic and occasionally on the nuclear membrane. Amounts of BAX protein were high in liver, renal tubules, endocrine islets of the pancreas, gastric glands, cardiac muscle, epididymis, lymph node germinal centers, and neurons; intermediate in the colon, stomach, bronchus. Fallopian tube, salivary gland, breast, thymus, spleen, and testis; low or undetectable in the other tissues. BAX IHC positivity correlated with apoptotic features in neurons and germinal center lymphocytes. There was no strict correlation between the IHC profiles of BAX and BCL-2 expression, although a reciprocal pattern of staining was observed in lymph node and colon. This report shows the usefulness the monoclonal antibody anti-BAX 4F11 on paraffin sections and demonstrates that the human BAX tissular distribution is close to, but not similar, to the profile observed in the mouse. The widespread BAX expression suggests that BAX alone is insufficient to trigger cell death in human tissues. BAX may either modulate the role of other regulators of apoptosis or carry out functions unrelated to apoptosis.

Animals↗

Role of induction chemotherapy and bone marrow transplantation in adult lymphoblastic lymphoma: a report on 62 patients from a single center.

OBJECTIVE: To describe the outcome of an unselected large series of patients with lymphoblastic lymphoma (LBL) treated in a single institution. PATIENTS AND METHODS: Sixty-two patients were treated between 1980 and 1992. Induction chemotherapy (CT) to achieve complete response (CR) was: French Multicenter Acute Lymphoblastic Leukemia (ALL) protocols (38), non-Hodgkin's Lymphoma (NHL) protocols (20). Thirty patients underwent transplant after achieving CR (allogeneic 12; autologous 18). RESULTS: Forty-six patients (74%) achieved CR and 16 (26%) failed to respond. The patients who received an ALL induction had an 89% CR rate, while the CR rate was 52% in patients who received a NHL-like regimen. With a median follow-up of 93 months (range 36-187), the actuarial overall survival (OS) rate for all patients is 49% at five years and 41% at 10 years, and the actuarial event-free survival (EFS) rate is 45% and 37%. OS and EFS in the grafted population are, respectively, 60% and 56% at five years. Our results also show a trend toward a longer OS in allografted group. CONCLUSIONS: ALL induction therapy is more effective than the NHL-like regimen for augmenting the CR rate. Autologous or allogeneic transplantation should be considered as consolidation therapy in high-risk group patients.

Adolescent↗

Sensitivity to Fas-mediated apoptosis is null or weak in B-cell non-Hodgkin's lymphomas and is moderately increased by CD40 ligation.

The Fas receptor (APO-1/CD95) is capable of inducing apoptosis of lymphoid cells and is expressed in some non-Hodgkin's lymphomas (NHLs). Fas expression is up-regulated at the surface of normal B cells upon triggering of the CD40 receptor. In this report, we investigated the sensitivity of NHLs to Fas-mediated apoptosis induced by anti-Fas monoclonal antibodies (MAbs) and its possible modulation by CD40 ligation in 18 NHL biopsy samples of various histological subtypes. Flow cytometric analysis showed that the fraction of Fas-expressing lymphoma cells was highly variable from sample to sample (from 1% to 93%, mean value 46%). The frequency of apoptotic cells was not significantly increased upon treatment with an anti-Fas MAb compared with control MAb in the 18 NHL cases analysed. The sensitivity of lymphoma cells to Fas-mediated apoptosis was correlated neither with the histological subtypes nor with the level of Fas expression. Activation of neoplastic B cells by CD40 ligation resulted in significant increases in Fas expression and Fas-induced apoptosis among the five B-NHL cases tested. The overall increase in apoptotic rates was moderate and remained lower in tumour samples than in control CD40-activated normal tonsil B cells. Altogether, our results indicate that the sensitivity to Fas-induced apoptosis is null or weak in NHL cells, irrespective of their histological subtype, and that it can be increased to a moderate and variable degree by CD40 ligation on neoplastic B cells. This may be an impediment to the development of Fas-based therapies for NHLs.

Apoptosis↗

Characterization of two monoclonal antibodies against the RON tyrosine kinase receptor.

RON is a receptor protein tyrosine kinase belonging to the hepatocyte growth factor (HGF) receptor family. Using Récepteur d'Origine Nantais (RON) transfected cell lines, Macrophage Stimulating Protein (MSP) was identified as the ligand of RON. RON is synthesized as a single chain precursor, which subsequently is cleaved to yield a disulfide-linked heterodimer, with a 40-kDa alpha chain and a 150-kDa beta chain. Activation of RON by MSP results in cell migration, shape change, and proliferation. The present work centers on the production and characterization of two monoclonal antibodies (MAbs) to RON called ID-1 and ID-2. Antibodies were generated by immunization of mice with Madin-Darby Canine Kidney (MDCK) cells expressing human RON (clone RE7). Both antibodies recognized the mature and precursor form of RON. The specificity of the anti-RON antibodies was confirmed using a hepatocarcinoma cell line HepG2 expressing both task MET and RON receptors. Specific immunoprecipitation with ID-1 and ID-2 or anti-MET antibody followed by Western blotting under reducing conditions with rabbit polyclonal antibodies against RON and MET showed that our anti-RON antibodies recognize specifically the RON receptor. Ligand binding experiments showed that both antibodies are able to block the binding of radiolabeled MSP to RON and showed also that the antibodies recognize two different epitopes in the molecule. The blocking of MSP binding to RON by the anti-RON antibodies was confirmed by inhibition of cell migration induced by MSP in HT-29-D4 cells. Significant immunostaining was not observed in any subpopulation of whole blood with either ID-1 or ID-2. We analyzed the expression of RON receptor in a number of human hematopoietic and nonhematopoietic cells lines by flow cytometry. We found a strong mean of fluorescence intensity (MFI) in colon adenocarcinoma cells SW620 and HT-29-D4, low MFI in SVK14 and HepG2 cells, and no immunostaining in melanoma, lymphoma, and leukemia cells. Immunohistochemistry revealed that RON was expressed in germinal centers of tonsil, in skin, small intestine, and colon. These antibodies defined RON as CDw136 during the last leucocyte typing VI.

Animals↗

BCL-X and the apoptotic machinery of lymphoma cells.

The BCL-X gene belongs to the family of BCL-2 homologues and plays an important role in the regulation of programmed cell death (PCD) in normal lymphoid tissues. BCL-X is transcribed into 2 mRNAs through alternative splicing. The protein product of the larger BCL-X mRNA (BCL-XL) functions as a PCD repressor. The second mRNA species, BCL-XS, encodes a protein capable of accelerating cell death. BCL-XL is a potential contributor to the pathogenesis of malignant lymphomas because the BCL-XL isoform is predominantly expressed by the neoplastic cells in the majority of lymphoma cases. This review is focused on the possible influence of BCL-X and other PCD regulatory agents on lymphomagenesis.

Apoptosis↗

In vivo expression of the CTLA4 inhibitory receptor in malignant and reactive cells from human lymphomas.

The CTLA4 receptor is a CD28 homologue which induces inhibitory effect on activated T-cells. Peripheral T-cells proliferate spontaneously in CTLA4-deficient mice. These results led to an analysis of CTLA4 expression in human lymphomas (n = 82) including Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHLs), using immunohistochemistry. CTLA4 was present in neoplastic cells from most (10/11) T-cell malignancies, except for anaplastic and lymphoblastic subtypes (0/4). Malignant B-cells from rare (3/55) B-NHLs (all of follicular subtype) were also CTLA4-positive. Other B-NHLs (52/55) were negative in malignant B-cells and occasionally positive in T-cells. Reactive small lymphocytes, but not Reed-Sternberg cells, from all (12/12) HD cases were strongly CTLA4-positive. The CTLA4 ligands CD80 and CD86 were simultaneously expressed in most CTLA4-negative lymphoma cases. CTLA4 is thus expressed either in the reactive or in the malignant cell populations, depending on the lymphoma subtype. These results provide new insights leading towards therapeutic strategies based either on enhancement of anti-tumour immunity by CTLA4 blockade in reactive lymphocytes or on triggering of a CTLA4-mediated inhibitory pathway in lymphoma cells.

Abatacept↗

Cysteine protease CPP32, but not Ich1-L, is expressed in germinal center B cells and their neoplastic counterparts.

Ich-1/Nedd2 and CPP32/YAMA are cysteine proteases related to interleukin 1-beta-converting enzyme (ICE), which act as apoptosis effectors. Both molecules are expressed in T- and B-cell lines. The authors investigated their in vivo cellular distribution in normal and neoplastic human lymphoid tissues. Sixty-eight representative non-Hodgkin's lymphomas (NHL) and Hodgkin's disease (HD) samples, normal lymphoid organs, and nonlymphoid tumors were analyzed by immunohistochemistry (IHC). CPP32 expression in benign tissues was restricted to germinal center B cells, plasma cells, and a few interfollicular immunoblasts. All follicular NHLs and most diffuse large cell NHLs were CPP32 positive. Among T-cell NHLs, CPP32 expression was mainly observed in anaplastic large cell NHLs, whereas the other subtypes were less frequently positive. In contrast, lymphoid organs displayed only weak Ich1-L expression, located in sinusal histiocytes and thymic epithelial cells. Lymphomas were Ich1-L negative, except for T-cell-rich B-cell NHLs, and about half of the HD samples, in which Reed-Sternberg cells (RSC) were usually Ich1-L positive/CPP32 negative. Extralymphoid Ich1-L reactivity was found in particular organs like the kidney and various tumors. Western blot analysis confirmed the specificity of immunostaining. Neither CPP32 nor Ich1-L expression were correlated with intratumoral DNA fragmentation, as determined by the TUNEL assay. Altogether, these results indicate that CPP32 is preferentially expressed in germinal centers and thus could be involved in B-cell maturation. The differential expression of CPP32 and Ich1-L suggests that cysteine proteases differ in substrate specificities and carry out functions unrelated to apoptosis.

Apoptosis↗

Malignant and reactive cells from human lymphomas frequently express Fas ligand but display a different sensitivity to Fas-mediated apoptosis.

Fas ligand (FasL) is capable of inducing apoptosis of lymphoid cells by cross-linking with its natural receptor, Fas. We aimed to investigate the possible role of the Fas/FasL-mediated apoptosis in the development of human lymphomas. FasL mRNA was detected by reverse transcriptase-polymerase chain reaction in 38 out of 63 lymphoma biopsy specimens representative of various subtypes of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease. FasL was co-expressed with Fas mRNA in most cases. Flow cytometry (FACS) analysis showed a bright FasL staining in 31% to up to 75% of the total cell population from 14 out of 16 samples; the presence of the FasL protein was confirmed by Western blotting. Dual-color FACS analysis showed that FasL was expressed by T cells in B-NHLs and T-NHLs. A significant percentage of B cells in various B-NHLs also stained positively for FasL. Freshly separated neoplastic B cells from three FasL+ and one FasL- B-NHLs displayed a relative resistance to Fas-mediated apoptosis, when compared to reactive T cells isolated from the same tissue samples. In contrast, the sensitivity to Fas-mediated killing of the T cells isolated from two FasL+ T-NHLs was not uniform. These data show that (1) FasL is expressed in both neoplastic and reactive cells from a significant proportion of lymphoma cases, and (2) that the intratumoral FasL+/Fas+ reactive T cells are more sensitive to Fas-induced apoptosis than the neoplastic FasL+/Fas+ malignant B cells. A putative defect in the Fas/FasL pathway may thus favor the development of malignant B cell populations.

Apoptosis↗

Fas ligand is not only expressed in immune privileged human organs but is also coexpressed with Fas in various epithelial tissues.

AIMS: To confirm the recent data obtained in mice, showing that the Fas ligand (FasL) is involved in the phenomenon of "immune privilege" (the apparent defect of the immune system in specific anatomical sites) and to extend this finding to humans. METHODS: The expression of FasL was analysed in a panel of histologically normal human tissues by reverse transcriptase polymerase chain reaction and Western blotting. The tissues sampled were brain, breast, bone marrow, oesophagus, kidney, liver, lung, lymph node, ovary, pancreas, pituitary gland, prostate, spleen, stomach (antrum and fundus), striated muscle, testis, thyroid, and uterus. These were obtained from patients with various neoplastic and non-neoplastic disorders; placental tissue was obtained after normal obstetric delivery, and spontaneous or voluntary abortion. RESULTS: Strong FasL expression was detected in testis and placenta. FasL expression was also detectable, although it was seen to a lesser extent, in oesophagus, prostate, lung, and uterus, which also coexpressed variable amounts of Fas mRNA or protein or both. The other organs tested for FasL expression were all negative. CONCLUSIONS: FasL in humans is expressed predominantly in immune "sanctuaries" such as testis and placenta, suggesting that, similar to mice, this expression may contribute to the immune privileged status of these organs, by preventing dangerous inflammatory responses. The coexpression of FasL and Fas in particular epithelia suggests that the physiological cell turnover of some tissues may be regulated by the Fas-FasL apoptotic pathway.

Blotting, Western↗

Intensive sequential chemotherapy with repeated blood stem-cell support for untreated poor-prognosis non-Hodgkin's lymphoma.

PURPOSE: To demonstrate the feasibility and efficacy of six ambulatory high-dose sequential chemotherapy courses that include three intensified cycles supported by stem-cell infusion in high-risk and high-intermediate-risk untreated non-Hodgkin's lymphoma (NHL) patients. PATIENTS AND METHODS: A pilot nonrandomized study included 20 untreated patients aged less than 60 years with aggressive histologically identified NHL and two or three adverse-prognosis criteria (International Index). Patients received an ambulatory regimen with high-dose chemotherapy supported by granulocyte colony-stimulating factor (G-CSF) and repeated peripheral-blood stem-cell (PBSC) infusion. The median age was 39 years (range, 20 to 59), with 13 men and seven women. Chemotherapy consisted of one cycle every 21 days for a total of six cycles. The first three cycles (A1, A2, and A3) consisted of cyclophosphamide (Cy) 3,000 mg/m2, doxorubicin (Doxo) 75 mg/m2, and vincristine 2 mg (plus corticosteroids). The last three cycles (B4, B5, and B6) consisted of the same drug combination plus etoposide 300 mg/m2 and cisplatin 100 mg/m2. For an expected duration of 18 weeks, the projected dose-intensity was 25 mg/m2/wk for Doxo and 1,000 mg/m2/wk for Cy. G-CSF 300 micrograms was administered from day 6 following each cycle until neutrophil reconstitution. Two aphereses were performed at approximately day 13 after each A cycle, and PBSCs were injected at day 4 of each B cycle. Radiotherapy on tumor masses > or = 5 cm was scheduled after completion of the last cycle. RESULTS: The median duration of grade 4 neutropenia was 1 day (range, 0 to 7) for each A cycle and 4 days (range, 1 to 10) for each B cycle (P = .02). The median duration of grade 4 thrombopenia was 0 days (range, 0 to 8) for each A cycle and 6 days (range, 1 to 21) for each B cycle (P < .001). Hospitalization for febrile neutropenia was required for 18% and 44% of patients during cycles A and B, respectively (P < .01). Only three patients did not complete the protocol: one due to emergency surgery after cycle B4, one who died after cycle B5 from interstitial pneumonia, and one with delayed hematologic reconstitution after cycle B4. Chemotherapy delivery was optimal (median actual relative dose-intensity, 97%; range, 66 to 100). The median total dose administered over 18 weeks was 18,000 mg Cy (range, 12,000 to 18,000), 450 mg Doxo (range, 300 to 450), 900 mg etoposide (range, 300 to 900), and 300 mg cisplatin (range, 100 to 300). Evaluation of response after six courses showed 13 complete remissions ([CRs] 65%), four partial remissions (PRs), two nonresponses (NRs), and one toxic death. With a median follow-up period of 25 months (range, 16 to 43), 15 patients are alive, with 12 in continuous first CR; five patients relapsed (four of four PRs and one of 13 CRs). Two-year survival and failure-free survival (FFS) rates are 73% and 56%, respectively. The disease-free survival (DFS) rate for the CRs is 86%. CONCLUSION: PBSC support contributes to the feasibility of first-line, very-high-dose, ambulatory chemotherapy delivery in poor-risk NHL and is associated with a high rate of remission and FFS.

Adult↗

[Clear cell sarcoma of the kidney relapsing after 10 years of asymptomatic evolution].

We report the case of a kidney tumor occurring in a thirteen year-old girl. This tumor was first diagnosed and treated as a benign one. After ten years without recurrence, a relapse occurred. The diagnosis was recurrent clear cell sarcoma of the kidney. The course in our case is uncommon because clear cell sarcoma of the kidney is a rare and aggressive pediatric neoplasm, usually characterized by a predilection for bone metastases, and a mid survival rate of 30 months without treatment.

Adolescent↗

Molecular analysis of the NPM-ALK rearrangement in Hodgkin's disease.

The fusion gene NPM-ALK occurs in a subset of anaplastic large cell lymphomas (ALCLs), as a result of a chromosomal translocation, t(2;5) (p23;q35). It has been suggested that Hodgkin's disease (HD) and ALCL share a common histogenesis because of pathological and phenotypical similarities. In order to check this hypothesis, reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to detect the hybrid NPM-ALK gene in 30 tumour samples, including 22 lymph node biopsies from HD and eight ALCL specimens. The threshold level of sensitivity was shown to reach at least 1/10(4) by dilution experiments using cell lines as positive and negative controls. The expected 177 bp product indicative of the NPM-ALK rearrangement was identified in Karpas 299 and SUDHL-1 cell lines and in two out of eight ALCLs. The 22 HD cases were negative, even after two successive tests. Thus, since the ALCL-specific genetic alteration was absent in our series of HD cases, the present study does not support the hypothesis that HD and ALCL are histogenetically related entities.

Adult↗

Predominant expression of the long isoform of Bcl-x (Bcl-xL) in human lymphomas.

Bcl-x is a member of the bcl-2 family of proteins which are characterized by their ability to modulate apoptosis. Alternative splicing results in two distinct bcl-x mRNAs encoding a long isoform, bcl-xL, which acts as a bcl-2 agonist; and a short isoform, bcl-xS, which inhibits bcl-2 effects. The aim of the study was to determine whether bcl-x is expressed in lymphoma tissues and to characterize the respective production of bcl-xs and bcl-xL. We investigated the expression of bcl-x mRNA in a series of 50 non-Hodgkin's lymphomas (NHL) and Hodgkin's disease (HD) cases using a RT-PCR method in order to amplify both transcripts simultaneously, and to estimate their relative abundance. The rearrangements of the bcl-2 gene were analysed by RT-PCR expression of the hybrid bcl-2-lgH mRNA. In addition, 20 PCR-positive NHL cases and three HD cases were analysed by immunohistochemistry using bcl-x polyclonal antisera. RT-PCR showed bcl-x expression in 43/45 NHLs and 5/5 HD cases. The bcl-xL transcript was predominant in all positive cases and was associated with variable amounts of bcl-xS. There was no significant correlation between the profile of bcl-xL/bcl-xS expression and the histological and immunological subtyping. Bcl-x immunodetection was positive in the neoplastic cell component in all analysed cases, but the degree of staining was highly variable between cases. Expression of the hybrid bcl-2-IgH gene was detected by RT-PCR in five cases of follicular NHL and in one case of HD, but this group of tumours did not display a particular profile of bcl-xL/bcl-xS expression. We conclude that bcl-x is commonly expressed by malignant cells in various types of malignant lymphomas, with a predominance of the bcl-xL transcript. Since the corresponding bcl-xL isoform can block the cell death machinery and potentialize bcl-2 effects, it may be involved in some pathways of lymphomagenesis.

Base Sequence↗