EZH2 alterations in follicular lymphoma: biological and clinical correlations.

The histone methyltransferase EZH2 has an essential role in the development of follicular lymphoma (FL). Recurrent gain-of-function mutations in EZH2 have been described in 25% of FL patients and induce aberrant methylation of histone H3 lysine 27 (H3K27). We evaluated the role of EZH2 genomic gains in FL biology. Using RNA sequencing, Sanger sequencing and SNP-arrays, the mutation status, copy-number and gene-expression profiles of EZH2 were assessed in a cohort of 159 FL patients from the PRIMA trial. Immunohistochemical (IHC) EZH2 expression (n=55) and H3K27 methylation (n=63) profiles were also evaluated. In total, 37% of patients (59/159) harbored an alteration in the EZH2 gene (mutation n=46, gain n=23). Both types of alterations were associated with highly similar transcriptional changes, with increased proliferation programs. An H3K27me3/me2 IHC score fully distinguished mutated from wild-type samples, showing its applicability as surrogate for EZH2 mutation analysis. However, this score did not predict the presence of gains at the EZH2 locus. The presence of an EZH2 genetic alteration was an independent factor associated with a longer progression-free survival (hazard ratio 0.58, 95% confidence interval 0.36-0.93, P=0.025). We propose that the copy-number status of EZH2 should also be considered when evaluating patient stratification and selecting patients for EZH2 inhibitor-targeted therapies.

Uterus transplantation in France: for which patients?

OBJECTIVE: Uterine infertility (UI), which can be caused by a variety of congenital or acquired factors, affects several thousand women in Europe. Uterus transplantation (UTx), at the current stage of research, offers hope for these women to be both the biological mother and the carrier of their child. However, the indications of UTx still need to be defined. The main aim of the study was to describe the different etiologies of UI and other data as marital and parental status from women requesting UTx who contacted us in the framework of a UTx clinical trial. Secondarily, we discussed the potential indications of UTx and their feasibility. STUDY DESIGN: This is an observational study. RESULTS: Of a total of 139 patients with UI, 105 patients (75.5%) had uterine agenesis, making it the leading cause of UI in this sample. Among the patients with uterine agenesis, 25% had a solitary kidney and 44.7% had undergone vaginal reconstruction. Peripartum hysterectomy, hysterectomy for cancer, and hysterectomy for benign pathologies accounted for 9.4%, 7.2% and 5% of cases, respectively. Less common causes of UI included complete androgen insensitivity syndrome (2.2% of patients) and prenatal diethylstilbestrol exposure (0.7%). Approximately 14% of the women already had at least one child and 66% were in a couple living together for at least 2 years. CONCLUSION: UTx is still under evaluation and further research is under way. Nulliparous patients with no major medical or surgical history and with normal ovarian function, who meet the legal criteria for medically assisted reproduction, represent the best indications for UTx at this stage of its development.

[Hysterectomy for benign gynaecological disease: Surgical approach, vaginal suture method and morcellation: Guidelines]. / Hystérectomie pour pathologie bénigne: choix de la voie d'abord, technique de suture vaginale et morcellement: recommandations.

OBJECTIVE: To provide clinical practice guidelines from the French college of obstetrics and gynaecology (CNGOF), based on the best evidence available, concerning the surgical approach, the vaginal suture method, the surgeon's experience and morcellation to avoid complications with hysterectomy for benign gynaecological disease. MATERIAL AND METHODS: English and French review of literature about complications with hysterectomy for benign gynaecological disease, excluding cancer. RESULTS AND CONCLUSION: For benign gynaecological disease, vaginal (VH) or laparoscopic (LH) hysterectomy are recommended (grade B). In case of big uterus, VH or LH are recommended (grade C). VH is not contraindicated in nulliparous (Grade C). VH is not contraindicated in case of previous caesarean (grade C). In obese women, VH and LH are recommended (grade C). It should be recommended to perform at least 30 hysterectomies during learning curve (grade C). Hysterectomy should be performed by surgeon doing at least 10 hysterectomies each year (grade C). No vaginal suture method is recommended (grade C). It is recommended to assess cancer risk before (histological sample and/or imagery) when morcellation is planned (expert opinion).

[Urinary, infectious and digestive adverse events related to benign hysterectomy and the associated surgery on the Fallopian tube: Guidelines]. / Hystérectomies d'indication bénigne: complications viscérales et gestes associés sur les annexes: recommandations.

OBJECTIVES: To provide clinical practice guidelines from the French College of Obstetrics and Gynecology (CNGOF) based on the best evidence available, concerning the urinary, infectious and digestive adverse events related to benign hysterectomy and the associated surgery including opportunistic salpingectomy and adnexectomy. MATERIAL AND METHOD: Review of literature using following keywords: benign hysterectomy; urinary injury; bladder injury; ureteral injury; vesicovaginal fistula; infection; bowel injury; salpingectomy. RESULTS: Urinary catheter should be removed before 24h following uncomplicated hysterectomy (grade B). In case of urinary catheter during hysterectomy, immediate postoperative removal is possible (grade C). No hemostasis technics can be recommended to avoid urinary injury (grade C). There is not any evidence to recommend to perform a window in the broad ligament or an ureterolysis, to put ureteral stent or a uterine manipulator in order to avoid ureteral injury. An antibiotic prophylaxis by a cephalosporin is always recommended (grade B). Mechanical bowel preparation before hysterectomy is not recommended (grade B). If there is no ovarian cyst/disease and no familial or personal history of ovarian/breast cancer, ovarian conservation is recommended in premenopausal women (grade B). In postmenopausal women, informed consent and surgical approach should be taken in account to perform a salpingo-oophorectomy. Since the association salpingectomy and hysterectomy is not assessed in the prevention of ovarian cancer, systematic bilateral salpingectomy is not recommended (expert consensus). CONCLUSIONS: Practical application of these guidelines should decrease the prevalence of visceral complications associated with benign hysterectomy.

[Hysterectomy for benign pathology: Guidelines for clinical practice]. / Hystérectomie pour pathologie bénigne: recommandations pour la pratique clinique.

OBJECTIVE: The objective of the study was to provide guidelines for clinical practice from the French college of obstetrics and gynecology (CNGOF), based on the best evidence available, concerning hysterectomy for benign pathology. METHODS: Each recommendation for practice was allocated a grade which depends on the level of evidence (guidelines for clinical practice method). RESULTS: Hysterectomy should be performed by a high volume surgeon (>10 procedures of hysterectomy per year) (grade C). Rectal enema stimulant laxatives are not recommended prior to hysterectomy (grade C). It is recommended to carry out vaginal disinfection using povidone iodine solution prior to an hysterectomy (grade B). Antibioprophylaxis is recommended during a hysterectomy, regardless of the surgical route (grade B). The vaginal or the laparoscopic routes are recommended for hysterectomy for benign pathology (grade B), even if the uterus is large and/or the patient is obese (grade C). The choice between these two surgical approaches depends on others parameters, such as the surgeon's experience, the mode of anesthesia and organizational constraints (operative duration and medico economic factors). Hysterectomy by vaginal route is not contraindicated in nulliparous women (grade C) or in women with previous c-section (grade C). No specific technique to achieve hemostasis is recommended with a view to avoid urinary tract injuries (grade C). In the absence of ovarian pathology and personal or family history of breast/ovarian carcinoma, it is recommended to conserve ovaries in pre-menopausal women (grade B). Subtotal hysterectomy is not recommended in order to diminish the risk of per- or postoperative complications (grade B). CONCLUSION: The application of these recommendations should minimize risks associated with hysterectomy.

Unr, a cytoplasmic RNA-binding protein with cold-shock domains, is involved in control of apoptosis in ES and HuH7 cells.

Unr (upstream of N-ras) is a cytoplasmic RNA-binding protein involved in the regulation of messenger RNA stability and internal initiation of translation. We have used Unr-deficient murine embryonic stem (ES) cells to analyse Unr role in cell proliferation and response to stress. Disruption of both unr gene copies had no effect on ES cell proliferation. However, after ionizing radiation (IR), clonogenic survival of unr(-/-) ES cells was approximately 3-fold enhanced as compared to unr(+/+) cells. We further determined that IR-induced apoptosis was decreased in unr(-/-) ES cells, and that reintroduction of the unr gene in unr(-/-) cells restored normal IR-induced apoptosis. Three pro-apoptotic genes, p53, caspase-3 and Gadd45gamma, were downregulated in unr(-/-) ES cells, indicating that Unr, as other cytoplasmic RNA-binding proteins, regulates a complex genetic program, promoting cell death after IR. In contrast, in the human hepatoma cell line HuH7, Unr knockdown using unr-specific small interfering RNAs induced apoptosis, both in untreated and gamma-irradiated cells. Thus, our results establish that Unr acts as a positive or negative regulator of cell death, depending on the cell type. Manipulating the level of Unr may constitute a specific approach to sensitize cancer cells to anticancer treatments.

Lack of genotoxicity of potassium iodate in the alkaline comet assay and in the cytokinesis-block micronucleus test. Comparison to potassium bromate.

Iodine could be added to the diet of human population in the form of iodide or iodate but iodate had not been adequately tested for genotoxicity and carcinogenicity. In the present study, genotoxic effects of potassium iodate were evaluated in vitro using the alkaline comet assay and the cytokinesis-block micronucleus assay on CHO cells and compared to halogenate salt analogues potassium bromate and chlorate and also to their respective reduced forms (potassium iodide, bromide and chloride). The results showed that the comet assay failed to detect the presence of DNA damage after a treatment of cells by potassium iodate for concentrations up to 10 mM. This absence of primary DNA damage was confirmed in the cytokinesis-block micronucleus assay. In the same way, results showed that potassium chlorate as well as potassium iodide, bromide and chloride did not induced DNA damage in the alkaline comet assay for doses up to 10 mM. By contrast, potassium bromate exposure led to an increase in both DNA damage and frequency of micronucleated cells. The repair of bromate-induced DNA damage was incomplete 24 h after the end of treatment. These results seem to indicate that potassium bromate would induce DNA damage by several mechanisms besides oxidative stress.

High glucose and hyperinsulinemia stimulate connective tissue growth factor expression: a potential mechanism involved in progression to fibrosis in nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) may progress to liver fibrosis and cirrhosis. Mechanisms directly involved in the development of fibrosis have been poorly investigated. Because connective tissue growth factor (CTGF) is an intermediate key molecule involved in the pathogenesis of fibrosing chronic liver diseases and is potentially induced by hyperglycemia, the aims of this study were to (1) study the expression of CTGF in vivo both in human liver biopsy specimens of patients with NASH and in an experimental model of obesity and type II diabetes (Zucker rats); and (2) analyze the effects of hyperglycemia and insulin in vitro on hepatic stellate cells. In vivo, CTGF overexpression was observed in the liver tissue of all of the 16 patients with NASH. CTGF immunostaining was mild in 7 cases (44%) and moderate or strong in 9 cases (56%). Staining was mainly detected in the liver extracellular matrix in parallel with the amount of liver fibrosis. Liver from fa/fa rats also showed CTGF overexpression by comparison with Fa/fa rats both at the messenger RNA (mRNA) level (3-fold increase) and protein level. In vitro, both CTGF mRNA and protein were significantly increased when hepatic stellate cells were incubated with either glucose or insulin. A slight increase in type I procollagen mRNA level was also observed in hepatic stellate cells incubated with glucose. In conclusion, this study suggests that hyperglycemia and insulin are key-factors in the progression of fibrosis in patients with NASH through the up-regulation of CTGF.

Comparative in vitro and in vivo assessment of genotoxic effects of etoposide and chlorothalonil by the comet assay.

The alkaline single cell gel electrophoresis (comet) assay was used to assess in vitro and in vivo genotoxicity of etoposide, a topoisomerase II inhibitor known to induce DNA strand breaks, and chlorothalonil, a fungicide widely used in agriculture. For in vivo studies, rats were sacrificed at various times after treatment and the induction of DNA strand breaks was assessed in whole blood, bone marrow, thymus, liver, kidney cortex and in the distal part of the intestine. One hour after injection, etoposide induced DNA damage in all organs studied except kidney, especially in bone marrow, thymus (presence of HDC) and whole blood. As observed during in vitro comet assay on Chinese hamster ovary (CHO) cells, dose- and time-dependent DNA effects occurred in vivo with a complete disappearance of damage 24 h after administration. Even though apoptotic cells were detected in vitro 48 h after cell exposure to etoposide, such a result was not found in vivo. After chlorothalonil treatment, no DNA strand breaks were observed in rat organs whereas a clear dose-related DNA damage was observed in vitro. The discrepancy between in vivo and in vitro models could be explained by metabolic and mechanistic reasons. Our results show that the in vivo comet assay is able to detect the target organs of etoposide and suggest that chlorothalonil is devoid of appreciable in vivo genotoxic activity under the protocol used.

Influence of amino acid substitutions on antigenicity of immunodominant regions of the HTLV type I envelope surface gylcoprotein: a study using monoclonal antibodies raised against relevant peptides.

By the use of sera of human T cell leukemia virus type I (HTVL-I)-infected individuals it was shown that amino acid substitutions at positions 192 (proline to serine) and 250 (serine to proline) in major immunodominant regions (175-199 and 239-261) of the surface envelope glycoprotein (gp46) of the virus may influence the humoral response. Since human sera are polyclonal in nature, one cannot readily discriminate between an immunoglobulin-specific recognition and multiple bindings of diverse antibodies. To overcome this difficulty we generated murine monoclonal antibodies to synthetic peptides mimicking all or portions of these gp46 regions. The reactivity of some of these antibodies to synthetic peptides harboring (or not harboring) the preceding amino acid substitutions at position 192 or 250, to denatured gp46 by Western blotting, and to live (variously substituted) HTLV-I-infected cells, combined with blocking experiments with various peptides, allow us to conclude that the major epitopes (positions 183-191, 190-197, 190-199, and 246-252) in the two immunodominant regions may elicit different antibody responses according to their sequences. It is worth noting that in a reporter gene inhibition assay, it was found that a neutralizing monoclonal antibody (MF1), the epitope for which is located between residues 190 and 197, had a high level of activity when cells (2060) harboring a gp46 with proline at position 192 were used and had no activity toward cells (1010) with a serine at this position. Therefore our results establish that certain amino acid substitutions of gp46 may drastically affect the antigenicity of the molecule and the biological activity of the antibodies elicited.

A short amino-acid sequence in MH1 domain is responsible for functional differences between Smad2 and Smad3.

Smad proteins are essential components of the signalling cascade initiated by members of the Transforming Growth Factor-beta family. TGFbeta binding to heteromeric complexes of transmembrane Ser/Thr kinases induces Smad2 and Smad3 phosphorylation on their C terminus residues. This phosphorylation leads to oligomerization with Smad4, a common mediator of TGF-beta, activin and BMP signalling. The Smad complexes then translocate to the nucleus where they play transcription regulator roles. Even if they share 92% identity, the two TGFbeta/ restricted Smad2 and Smad3 are not functionally equivalent. As we have previously shown, Smad3 acts as a transcription factor by binding to a TGFbeta-responsive sequence termed CAGA box whereas Smad2 does not. Smad2 differs from Smad3 mainly in the N-terminal MH1 domain where it contains two additional stretches of amino acids that are lacking in Smad3. Here, we show that one of these domains corresponding to exon 3 is responsible for the absence of Smad2 transcriptional activity in CAGA box-containing promoters. Furthermore, in vitro studies indicate that this domain prevents Smad2 from binding to this DNA sequence. This suggests that Smad2 and Smad3 may have different subsets of target genes participating thus in distinct responses among TGFbeta pleiotropic effects.

[Epstein-Barr virus research by in situ hybridization in 65 cutaneous T cell epidermotropic lymphomas]. / Recherche de l'Epstein-Barr virus par hybridation in situ chez 65 malades atteints de lymphomes cutanés T épidermotropes.

BACKGROUND: The Epstein-Barr virus (EBV) is a highly mutagenic virus known to be the cause of several types of lymphoma. There has been some controversy concerning EBV in cutaneous T-cell lymphomas. The aim of this study was to search for EBV with a sensitive method: in situ hybridization in 65 patients with cutaneous T-cell lymphomas. PATIENTS AND METHODS: From 1990 to 1995, 158 samples from 65 patients with cutaneous T-cell lymphoma (2 stage IA, 12 IB, 4 IIA, 29 IIB, 16 Sézary syndrome, 2 stage IV) were collected. In situ hybridization with EBER and Bam W probes recognizing the viral latency genes were used to search for EBV. RESULTS: EBV was evidenced with at least one of the two probes in 43 samples (26 p. 100). Prior to alpha interferon treatment, 18 p. 100 of the samples were positive for EBER compared with 18 p. 100 for Bam W. After alpha interferon treatment, there was a significantly higher percentage of EBER positive samples (39 p. 100; p = 0.03). Inversely, there was no difference for the Bam W probe (p = 0.2). Clinical stage had no effect on the presence of EBV (p = 0.18). CONCLUSION: Our series evidenced the variable presence of EBV, identified by in situ hybridization, in cutaneous T-cell lymphoma. Few infiltrating cells are infected. This would be an argument in favor of an indirect role of the EBV in the transformation process. In addition, alpha interferon increases the life time of EBERs, sensitizing detection of this latency gene.

Doxorubicin-induced alterations of c-myc and c-jun gene expression in rat glioblastoma cells: role of c-jun in drug resistance and cell death.

We studied the effect of doxorubicin on the expression of c-myc and c-jun in the rat glioblastoma cell line C6 and its doxorubicin-resistant variant C6 0.5, at equitoxic exposures. For quantitation, the mRNA levels of these oncogenes were related to those of two domestic genes, beta-actin and glyceraldehyde phosphate dehydrogenase. After a transient overexpression of the genes during the first hour of incubation, there was a selective, dose-dependent down-regulation of both genes by doxorubicin in the sensitive cells. In the resistant cell line, c-myc expression was also decreased in response to doxorubicin incubation, but the expression of c-jun remained unchanged over the whole range of concentrations. In contrast, vincristine had no effect on the amounts of c-myc and c-jun mRNAs in either line. The effect of doxorubicin on the mRNA levels of c-jun was also observed on the JUN proteins by immunoblotting, but the MYC protein levels remained unchanged upon doxorubicin treatment. There was a significant correlation between the levels of c-myc and c-jun gene expression and the degree of growth inhibition induced by doxorubicin. In addition, doxorubicin induced a fragmentation of DNA in sensitive cells, but not in resistant cells, thus revealing a resistance to apoptosis in this line. Doxorubicin-induced cell death did not appear to be mediated by p53 in either cell line.

Direct binding of Smad3 and Smad4 to critical TGF beta-inducible elements in the promoter of human plasminogen activator inhibitor-type 1 gene.

Smad proteins play a key role in the intracellular signalling of transforming growth factor beta (TGF beta), which elicits a large variety of cellular responses. Upon TGF beta receptor activation, Smad2 and Smad3 become phosphorylated and form heteromeric complexes with Smad4. These complexes translocate to the nucleus where they control expression of target genes. However, the mechanism by which Smads mediate transcriptional regulation is largely unknown. Human plasminogen activator inhibitor-1 (PAI-1) is a gene that is potently induced by TGF beta. Here we report the identification of Smad3/Smad4 binding sequences, termed CAGA boxes, within the promoter of the human PAI-1 gene. The CAGA boxes confer TGF beta and activin, but not bone morphogenetic protein (BMP) stimulation to a heterologous promoter reporter construct. Importantly, mutation of the three CAGA boxes present in the PAI-1 promoter was found to abolish TGF beta responsiveness. Thus, CAGA elements are essential and sufficient for the induction by TGF beta. In addition, TGFbeta induces the binding of a Smad3/Smad4-containing nuclear complex to CAGA boxes. Furthermore, bacterially expressed Smad3 and Smad4 proteins, but not Smad1 nor Smad2 protein, bind directly to this sequence in vitro. The presence of this box in TGF beta-responsive regions of several other genes suggests that this may be a widely used motif in TGF beta-regulated transcription.

Reference method for detection of Pgp mediated multidrug resistance in human hematological malignancies: a method validated by the laboratories of the French Drug Resistance Network.

Multidrug resistance (MDR) associated with overexpression of the MDR1 gene and of its product, P-glycoprotein (Pgp), plays an important role in limiting cancer treatment efficacy. Many studies have investigated Pgp expression in clinical samples of hematological malignancies but failed to give definitive conclusion on its usefulness. One convenient method for fluorescent detection of Pgp in malignant cells is flow cytometry which however gives variable results from a laboratory to another one, partly due to the lack of a reference method rigorously tested. The purpose of this technical note is to describe each step of a reference flow cytometric method. The guidelines for sample handling, staining and analysis have been established both for Pgp detection with monoclonal antibodies directed against extracellular epitopes (MRK16, UIC2 and 4E3), and for Pgp functional activity measurement with Rhodamine 123 as a fluorescent probe. Both methods have been validated on cultured cell lines and clinical samples by 12 laboratories of the French Drug Resistance Network. This cross-validated multicentric study points out crucial steps for the accuracy and reproducibility of the results, like cell viability, data analysis and expression.

In vitro production of human antigen presenting cells issued from bone marrow of patients with cancer.

In the prospect of producing autologous antigen presenting cells (APC) to actively immunize patients with cancer against their own tumor we were interested in the in vitro generation of MC and/or dendritic cells. We observed that the best yielding in CD14+ cells was obtained by adding SCF and GM-CSF into RPMI 1640 completed medium and by using Teflon bags as culture-containers. The others growth factors tested (LIF, IL3 and M-CSF) were useless in term of production of macrophages. After a month of culture we usually obtained an average of 80% of CD14, CD33, CD64, CD11a, CD11b, CD11c and HLA-DR positive cells expressing the MGG staining phenotype of MC. For DC the best association of growth factors combined GM-CSF, IL-4 and SCF. Hence we could obtained at least 60% of CD1a+, CD14-, CD54+, CD58+, CD80+ and HLA DR+ dendritic cells.

Measuring multidrug resistance expression in human malignancies: elaboration of consensus recommendations.

Before the prognostic significance of P-glycoprotein (P-gp) expression can be properly evaluated in prospective clinical trials of P-gp modulators, standard techniques for the measurement of P-gp must be widely accepted. Several multicenter trials have demonstrated large discrepancies in the observed levels of P-gp expression in the same clinical samples evaluated at different centers. The greatest discrepancies occurred with samples that expressed low levels of P-gp. Although standardized procedures have dramatically increased the interlaboratory reproducibility of flow cytometry and polymerase chain reaction assays, data from immunocytochemistry remain difficult to interpret. Consensus recommendations are presented for improving data reproducibility. These recommendations emphasize the importance of using calibrated batches of antibodies and two different antibodies for immunocytochemistry, the need for an internal standard for reverse transcriptase-polymerase chain reaction (RT-PCR) assays, the need for the presentation of data as a continuous variable, and the need for setting standard parameters for flow cytometry. It is also extremely important for the success of clinical trials that multiple techniques be employed to insure accurate measurement of P-gp expression.

Comparison of quantitative and semiquantitative methods of assessing MIB-1 with the S-phase fraction in breast carcinoma.

Different methods of assessing cell proliferation in breast cancer are currently being evaluated. Inherent qualities are required for such methods to be used on a routine basis in a pathology laboratory. Such qualities include high sensitivity and specificity in recognizing proliferating cells, simplicity in execution, and reproducibility. The MIB-1 antibody permits the immunohistochemical detection of the Ki67 antigen in fixed and paraffin-embedded tissue sections. The aim of our study was to compare a semiquantitative and quantitative method of assessing MIB-1 immunostaining with the S-phase fraction (SPF) determined by flow cytometry in a series of 112 breast carcinomas. The median semiquantitative MIB-1 score (SQ-MIB-1) in our series was 27.5%. The median quantitative MIB-1 score (B.MIB-1) was 563 positive neoplastic cells per square millimeter of tumor, and, when corrected by the volume percentage nuclei (C.MIB-1), 2844 positive nuclei per square millimeter of total nuclear area. These three indices were strongly correlated to the SPF (r = 0.73, 0.72, 0.72, n = 78), respectively for SQ.MIB-1, B.MIB-1, and C.MIB-1, MIB-1, assessed quantitatively or semiquantitatively, correlated with the Scarff, Bloom, and Richardson grade, including the mitotic index and nuclear grade, as well as with the progesterone receptor status. SQ.MIB-1 determination was easier and faster than B.MIB-1 and C.MIB-1 determination. A high correlation was found for SQ.MIB-1 results between two observers in this series (r = 0.92, n = 112), but the SQ.MIB-1 repeatability coefficient was 17.6%. Semiquantitation of MIB-1 is strongly correlated to the SPF and is an easy and rapid method of assessing cell proliferation. More studies are necessary for additional assessment of its reproducibility and its prognostic value in breast cancer.

Multicentric evaluation of the MDR phenotype in leukemia. French Network of the Drug Resistance Intergroup, and Drug Resistance Network of Assistance Publique-Hôpitaux de Paris.

The wide discrepancies in the frequency of 'positive' samples for multidrug resistance (MDR) phenotype within the same type of tumor observed in the literature justified the need for the definition of consensus recommendations. To define standard techniques of MDR phenotype measurement, we ran a large multicentric evaluation of the different methods available. Thirty-six French centers participated in the study, and 742 samples of 2-10 x 10(6) viable cells were sent by overnight express mail between December 1993 and February 1996. The same batches of MRK16, 4E3 and UIC2 were used. Nineteen samples of leukemia (12 AML, 1 ALL, 6 lymphoproliferative syndromes) and six leukemic cell lines with different levels of MDR expression were tested. Five meetings reached agreement concerning the guidelines for each technique, except immunocytochemistry. The 19 fresh samples were tested by each center using one to four techniques among cytofluorometry, immunocytochemistry, functional tests and RT-PCR. Five samples were diagnosed as 'negative' according to local criteria, with few discordant results (0 to 16% of 'positive' results). For all the 14 remaining samples, large discrepancies were observed from center to center, and from one technique to another. No correlations could be found between techniques. Flow cytometric analysis of cells already exposed to MRK16 or control IgG2A, fixed in paraformaldehyde and sent to centers did not reduce the discrepancies between centers in two of the four samples with moderate expression, emphasizing the role of histogram interpretation. The use of alternative monoclonal antibodies (4E3 and UIC2) did not reduce the discrepancies observed. In a second step, the K562 parental cell line, a low resistant subline (K562/HHT100, x7 resistance index to DNR) and a high resistant subline (K562/HHT300, x125 resistance index to DNR) were sent blindly three times, with an increasing level of recommendations for flow cytometry. Dramatic improvements were observed in cytometric results when the result was expressed as the ratio of arithmetic mean of fluorescence of antibody (10 microg of MRK16)/arithmetic mean of fluorescence of control (10 microg IgG2A): the proportion of expected results increased from 61 to 100% for K562, and from 37 to 85% for K562/HHT100. For uptake and drug efflux measurements, the use of 1 h uptake of 0.1 microM of rhodamine, followed by 1 h efflux +/-10 microM of verapamil, permitted an increased reproducibility of the technique from 71 to 100% for K562 and K562/HHT100. Whatever the technique used, concordant results were obtained for K562/HHT300. The immunocytochemistry, using several antibodies (MRK16, JSB1 and C219) gave many non-interpretable results (44%), due to a frequent high background and discordant results between antibodies in the same centers, and discordant conclusions between centers. The group does not recommend this technique for circulating tumoral cells.

Characterization of a new human liver myofibroblast cell line: transcriptional regulation of plasminogen activator inhibitor type I by transforming growth factor beta 1.

Myofibroblasts (MF) are a major effector cell type in liver fibrogenesis, where they are thought to derive from the activation of hepatic stellate cells. Cultured human MF, grown from liver explants, retain most of the in vivo characteristics of liver MF but are in limited supply. A continuous MF cell line would therefore be valuable in studying human liver fibrogenesis. For this purpose, we sought to immortalize human liver MF with polyoma virus large T antigen. MF were obtained from explants of human liver and transfected with a plasmid containing the coding sequence of polyoma virus large T antigen. This procedure yielded an activity growing cell line, designated GREF-X, which did not express large T antigen. Nevertheless, this cell line has been passaged repeatedly for almost 1 year and is thus likely immortalized. The morphology of GREF-X resembles that of primary liver MF. These cells have a doubling time of approximately 72 hours and are density-inhibited, and their growth is serum-dependent. Moreover, GREF-X cells do not grow in soft agar or induce tumors in nude mice, suggesting that they are not transformed. They stain positively for MF markers, such as smooth muscle alpha-actin and vimentin; express collagens type I, IV, V, and VI, fibronectin, and laminin: and secrete matrix-metalloproteinase-2. In addition, GREF-X cells are able to take up and esterify [3H]retinol, suggesting that they actually derive from hepatic stellate cells. Finally, these cells respond to transforming growth factor-beta 1, a major mediator of liver fibrogenesis, by increasing secretion of fibronectin and plasminogen activator-inhibitor type 1. Transient transfection experiments showed that plasminogen activator-inhibitor type 1 regulation, by transforming growth factor-beta 1, was transcriptional. We believe, therefore, that GREF-X would be a useful tool for studying the pathophysiology and pharmacology of liver fibrogenesis.