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Biomedical subjects

B Quesnel

Publications and source records attributed to B Quesnel.

At least 37 records · Page 2Linked to original sources
PubMed2000

gamma-ray irradiation induces B7.1 expression in myeloid leukaemic cells.

Expression of B7 molecules provides co-stimulatory signals to T lymphocytes, which prevent the induction of anergy. It has been previously reported that B7.1 gene transfer in a murine leukaemia model induced a potent antileukaemic immunity and that relative expression of B7.1 and B7.2 in human acute myeloid leukaemia (AML) had prognostic significance. As ex vivo engineering of leukaemic cells for immunotherapy protocols would require prior irradiation of these cells before reinjection to the patient, we investigated in murine and leukaemic cell lines and in 20 ex vivo primary cultured acute myeloid leukaemic cells the effect of gamma-irradiation on the expression of B7 molecules. We observed that gamma-irradiation enhanced B7.1 molecule expression in murine leukaemic cell lines and in B7.2 molecules in human HL60 and K562 cell lines. gamma-Irradiation induced B7.1 molecule expression in 90% AML samples but only 21% showed B7.2 molecule expression enhancement. B7.1 expression was increased both at the protein and RNA level in human AML cells but only at the protein level in the DA1-3b murine cell line. Oxidative stress increased B7.1 expression in the murine DA1-3b cell line but human cell lines and AML samples remained unaffected both by heat shock and oxidative stress, suggesting different pathways of B7.1 induction between mouse and human cells. Our data show that B7.1 expression can be induced by ex vivo irradiation of AML cells, indicating that these cells can express co-stimulatory molecules without gene transfer.

Animals↗
PubMed2000

Phase II study of 3-hour infusion of high dose paclitaxel in refractory and relapsed aggressive non-Hodgkin's lymphomas. Groupe d'Etude des Lymphomes de l'Adulte.

BACKGROUND AND OBJECTIVE: The first clinical studies of paclitaxel as a single agent for the treatment of relapsed or refractory low or intermediate grade non-Hodgkin's lymphomas (NHL) yielded controversial results regarding the response rates observed, mainly related to the dose and schedule of administration used. To obtain additional data concerning the efficacy and toxicity of paclitaxel in intermediate and high grade NHL we initiated a phase II study using a 3-hour infusion of high doses of paclitaxel. DESIGN AND METHODS: The eligibility criteria included patients with relapsed or refractory aggressive NHL, a performance status < or = 2 (WHO index), a platelet count > or = 100,000/microL, a neutrophil count > or = 2,000/microL, measurable disease, and adequate hepatic function. Patients were excluded if they were infected with HIV, had a left ventricular ejection fraction < 50%, or prior peripheral neuropathy. Paclitaxel was administered as a 3-hour infusion at a dose of 250 mg/m2 every 3 weeks for a maximum of 6 courses. RESULTS: Of 45 eligible patients, 42 received a total 73 courses of paclitaxel. Forty patients were assessable for response (89%), and 42 for toxicity (93%). Six patients (15%) achieved a partial (n = 4) or a complete remission (n = 2). Responses were observed in intermediate grade (n = 4) as well as in high grade lymphoma (n = 2). The main factor influencing the response to paclitaxel was the median duration of response to previous chemotherapy regimens which was 3 times longer in patients who responded to paclitaxel (16.3 months) than in patients who did not respond to paclitaxel (5.2 months) (p<0.05). The most common serious side effects were related to the hematologic toxicity of paclitaxel, and included grade IV granulocytopenia in 20 cases (48%), grade III/IV thrombocytopenia in 14 cases (33%) and grade III-IV anemia in 13 cases (31%). INTERPRETATION AND CONCLUSIONS: Despite frequent manageable hematologic toxicity, paclitaxel is usually well tolerated at a dose of 250 mg/m2 given by a 3-hour infusion. However, the clinical efficiency as a single therapy seems modest in relapsed or refractory aggressive lymphoma.

Adolescent↗
PubMed2000

[Gene therapy and ovarian cancer: update of clinical trials].

Ovarian cancer is the first leading cause of death from gynecologic cancer. Advances in therapy are needed to obtain complete response after surgery and/or chemotherapy. Gene therapy is a new alternative therapeutic approach. 380 gene therapy clinical trials (3173 patients) are going to be assessed. 63% of these trials concern therapy of cancer. 16 gene therapy clinical trails are applied to ovarian cancer. These 16 clinical trials assess different treatment strategies: Mutation compensation by replacement of an altered tumor suppressor gene (p53, BRCA1); Molecular chemotherapy by transfer of a suicide gene (HSV-tk gene); Antitumoral immunotherapy by cytokine gene transfer (IL2, IL12); Oncogene inhibition (erb-B2 gene); Multi Drug Resistance gene transfer. A knowledge of basis concepts of gene transfer strategies, is needed to understand these different treatment strategies. Thus, the goals of this review are, first, to provide the basis concepts of gene transfer strategies to the obstetrician-gynecologist and second, to submit recent gene therapy clinical trials about ovarian cancer.

Clinical Trials as Topic↗
PubMed1999

Transduction of bone marrow cells by the AdZ.F(pK7) modified adenovirus demonstrates preferential gene transfer in myeloma cells.

Adenoviral vectors can efficiently infect myeloma cell lines, but transduction of fresh myeloma cells performed at low multiplicity of infections (MOIs) showed only partial efficacy. The modified adenoviral vector AdZ.F(pK7), through binding of polylysines to heparan sulfate-containing receptors, could increase virus adsorption and gene transfer efficiency in myeloma cells, which express heparan sulfate-containing receptors. Thus, we investigated the ability of AdZ.F(pK7) vector to achieve efficient gene transfer in primary cultured fresh myeloma cells. Transduction of 16 primary cultured myeloma samples showed that gene transfer was much more efficient with AdZ.F(pK7) than with control AdZ.F. Both addition of soluble heparin and cell treatment with heparinase I dramatically inhibited gene transfer in myeloma cells by AdZ.F(pK7) but had no effect with AdZ.F, while addition of recombinant fiber protein inhibited AdZ.F but not AdZ.F(pK7), confirming that AdZ.F(pK7) gene transfer in myeloma cells is mediated by the targeting of heparan sulfates. AdZ.F(pK7) transduction of bone marrow cells showed that myeloma cells and hematopoietic progenitor AC133-, CD34-, and CD33-positive cells were efficiently transduced at an MOI of 100, but that only myeloma cells were significantly transduced at an MOI of 12. Thus, AdZ.F(pK7) vector seems to be well suited for immunological approaches of gene therapy or bone marrow-purging applications in multiple myeloma.

Adenoviridae↗
PubMed1999

Increased gene transfer in acute myeloid leukemic cells by an adenovirus vector containing a modified fiber protein.

Applications of gene transfer in acute myeloid leukemia (AML) blast cells have still not been developed, mostly due to the lack of an efficient vector. Adenoviruses have many advantages as vectors, but remain poorly efficient in cells lacking fiber receptors. A promising strategy is the retargeting of adenoviruses to other cellular receptors. We report the dramatic enhancement of gene transfer efficiency in AML blasts using AdZ.F(pK7), a modified adenovirus containing a heparin/heparan sulfate binding domain incorporated into the fiber protein of the adenovirus. We transduced 25 AML blast samples with efficiency reaching 100% of the cells in most samples. Optimal results were obtained at 8400 physical particles per cell, corresponding to a multiplicity of infection of 100 plaque forming units per cell. Control AdZ.F adenovirus efficiently transduced leukemic cell lines but gave poor results in AML samples. Both addition of soluble heparin and cell treatment with heparinase inhibited AdZ.F(pK7) gene transfer, showing that heparan sulfates are the major receptors mediating AdZ.F(pK7) transduction of AML blasts. Although adenoviruses can infect nondividing cells, we observed that a combination of growth factors (GM-CSF, IL-3, stem cell factor) was required for efficient transduction in order to maintain AML blast cell viability. This study demonstrates that retargeting the adenovirus fiber protein to heparan sulfates can overcome the low efficiency of adenovirus in AML blast cells and may provide a useful tool for gene therapy approaches in AML.

Acute Disease↗
PubMed1999

P15INK4b gene methylation and myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are clonal disorders, which frequently undergo leukemic transformation. It was recently shown that the promoter of the p15INK4b but not the p16INK4a gene is frequently and selectively hypermethylated in MDS. The p15INK4b gene is a cyclin dependent kinase inhibitor gene, which is actively transcribed after TGFbeta exposure. Methylation of the p15INK4b gene is significantly correlated with blastic bone marrow involvement, and sequential analyses have shown that methylation increases with disease evolution toward AML. These data strongly suggest that p15INK4b gene methylation is a mechanism allowing leukemic cells to escape to inhibitory signals from the bone marrow environment, however the exact role of p15INK4b gene methylation in disruption of the signal mediated by TGFbeta remains to be investigated.

Acute Disease↗
PubMed1998

Methylation of the p15(INK4b) gene in myelodysplastic syndromes is frequent and acquired during disease progression.

p15(INK4b) gene is an inhibitor of cyclin-dependent kinase (CDK) 4 and CDK6 whose expression is induced by transforming growth factor (TGF)beta. Recent reports suggest frequent methylation of the p15(INK4b) gene promoter in leukemias, and it has been proposed that this methylation could be necessary for leukemic cells to escape TGF beta regulation. We investigated the methylation status of p15(INK4b) gene in 53 myelodysplastic syndromes (MDS) cases, including nine that had progressed to acute myeloid leukemia (AML), using a recently described sensitive method where polymerase chain reaction (PCR) is preceded by bisulfite modification of DNA (methylation specific PCR). p15(INK4b) methylation was observed in 20 of 53 (38%) of the cases. Twenty of the 24 patients with greater than 10% bone marrow blasts had p15(INK4b) methylation (including all nine patients who had progressed to AML) as compared with none of MDS patients with <10% bone marrow blasts. No correlation between karyotypic abnormalities and methylation status was found. Patients with p15(INK4b) methylation had a worse prognosis, but the prognostic significance of p15(INK4b) methylation was no more found by multivariate analysis, due to its strong correlation to the percentage of marrow blasts. In 10 MDS cases, sequential DNA samples were available. In five of them, methylation of the p15(INK4b) gene was detected at leukemic transformation, but not at diagnosis. Our results showed that methylation of the p15(INK4b) gene in MDS is correlated with blastic bone marrow involvement and increases with disease evolution toward AML. It suggests that proliferation of leukemic cells might require an escape of regulation of the G1 phase of the cell cycle, and possibly of TGF beta inhibitory effect.

Carrier Proteins↗
PubMed1998

Cylin/CDK inhibitors of the 9p21 chromosomal region and hematological malignancies

9p21 chromosomal region contains p15INK4b and p16INK4a genes which regulate G1 phase of the cell cycle by inhibition of cyclin-cyclin dependent kinases. The p19ARF protein is translated from an alternative transcript of the p16INK4a gene and regulates G1 and G2 phase of the cell cycle by degradation of the MDM2 protein. p16INK4a and p15INK4b gene homozygous deletions occur mostly in acute lymphoblastic leukemia, ATL secondary to HTLV1 infection, and some lymphoma. Point mutations of p16INK4a or p15INK4b gene seem to be extremely rare, however selective methylations of the p15INK4b or p16INK4a promoters are frequently found in myelodysplastic syndromes and acute leukemias, or lymphomas and myelomas respectively. These data demonstrate that inactivation of gene of the 9p21 region is currently the main molecular event found in hematological malignancies.

Journal Article↗
PubMed1998

[Inhibitors of cyclins/CDK of the 9p21 chromosomal region and malignant hemopathies].

9p21 chromosomal region contains p15INK4b and p16INK4a genes which regulate G1 phase of the cell cycle by inhibition of cyclin-cyclin dependent kinases. The p19ARF protein is translated from an alternative transcript of the p16INK4a gene and regulates G1 and G2 phase of the cell cycle by degradation of the MDM2 protein. p16INK4a and p15INK4b gene homozygous deletions occur mostly in acute lymphoblastic leukemia, ATL secondary to HTLV1 infection, and some lymphoma. Point mutations of p16INK4a or p15INK4b gene seem to be extremely rare, however selective methylations of the p15INK4b or p16INK4a promoters are frequently found in myelodysplastic syndromes and acute leukemias, or lymphomas and myelomas respectively. These data demonstrate that inactivation of gene of the 9p21 region is currently the main molecular event found in hematological malignancies.

Cell Cycle Proteins↗
PubMed1996

Transfer of p16inka/CDKN2 gene in leukaemic cell lines inhibits cell proliferation.

The gene encoding for p16ink4a, a negative regulator of transition between G1 and S phase, is homozygously deleted in a large proportion of acute lymphoblastic leukaemias (ALL). Transfer of p16ink4a gene in several solid tumour cell lines with functional pRb and lacking both p16ink4a alleles has resulted in a dramatic reduction of cell proliferation, and the aim of this work was to confirm this effect in leukaemic (especially ALL) cell lines. We tested the proliferation in liquid medium and in soft agar after transfer of p16ink4a gene by a retroviral vector in leukaemic cell lines with homozygous p16ink4a gene deletion (K562, CEM, Jurkat cell lines) or with p16ink4a gene hemizygous deletion and a point mutation inactivating the remaining allele (HL60 cell line). The viral titre obtained after transfection of PA317 amphotropic packaging cell line, which has a p16ink4a gene homozygous deletion, was low, suggesting that p16ink4a gene expression could impair viral production of retroviral packaging cell lines derived from the NIH3T3 cell line. After retroviral transfer of p16ink4a in cell lines and G418 selection in liquid medium, a strong cell proliferation inhibition was observed for K562, CEM and Jurkat, but no inhibition was seen for HL60. A strong growth reduction in soft agar was also observed with p16ink4a-transduced CEM, Jurkat and K562 cells, with a moderate growth reduction in the HL60 cell line. The growth inhibition in liquid culture, of K562 and Jurkat cell lines, was confirmed by electroporation transfer of the p16ink4a gene. Our findings show that p16ink4a gene transfer has a growth-inhibitory effect in leukaemic cell lines with p16ink4a gene homozygous deletion. These data suggest that p16 could be a suitable gene for gene therapy in ALL.

Cell Division↗
PubMed1996

p16ink4a gene and hematological malignancies.

Progression of eukaryotic cells through major cell cycle transitions is mediated by sequential assembly and activation of regulators, the cyclin-dependent CDKkinases (CDKs). Recent studies have identified different CDK inhibitory genes (CDKis), and two of them, p16ink4a/MTS1/CDKN2 and p15ink4b/MTS2 are both mapped to chromosome 9p21 and inhibit cyclin D-CDK4 and -CDK6 complexes. A feedback regulatory loop involving pRb, p16ink4a, and CDKs seems to regulate G1/S phases transition. p16ink4a and p15ink4b are deleted in high frequency in human cell lines and in some fresh solid tumors. Point mutations of p16ink4a have also been sequenced, especially in familial melanomas and digestive cancers but preferential mechanism of p16ink4a/p15ink4b inactivation seems to be biallelic deletion. In hematological malignancies, homozygous deletions of p16ink4a and p15ink4b occur frequently in acute lymphoblastic leukemia (ALL) (14-40%), lymphoid type blast crisis of chronic myeloid leukemia (CML), and adult T cell leukemia (ATL), but p16ink4a deletions are more frequent than p15ink4b deletions, and hemizygous deletions of either p16ink4a and p15ink4b are rare. In ALL an association of homozygous deletions of p16ink4a and p15ink4b, and T-lineage, 9p abnormalities, and prognostic factors was found in some but not all reports. This review presents recent data on p16ink4a and p15ink4b functions and analyses their implications in hematological malignancies.

Adult↗
PubMed1995

p16 gene homozygous deletions in acute lymphoblastic leukemia.

The p16 protein is a cyclin inhibitor encoded by a gene located in 9p21, which may have antioncogenic properties, and is inactivated by homozygous p16 gene deletion or, less often, point mutation in several types of solid tumors often associated to cytogenetic evidence of 9p21 deletion. We looked for homozygous deletion and point mutation of the p16 gene in acute lymphoblastic leukemia (ALL), where 9p21 deletion or rearrangement are also nonrandom cytogenetic findings. Other hematologic malignancies including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), chronic lymphocytic leukemia (CLL), and myeloma were also studied. Homozygous deletion of the p16 gene was seen in 9 of the 63 (14%) ALL analyzed, including 6/39 precursor B-ALL, 3/12 T-ALL, and 0/12 Burkitt's ALL. Three of the 7 ALL with 9p rearrangement (including 3 of the 5 patients where this rearrangement was clearly associated to 9p21 monosomy) had homozygous deletion compared to 5 of the 55 patients with normal 9p (the last patient with homozygous deletion was not successfully karyotyped). Single stranded conformation polymorphism analysis of exons 1 and 2 of the p16 gene was performed in 88 cases of ALL, including the 63 patients analyzed by Southern blot. Twenty-six of the cases had 9p rearrangement, associated to 9p21 monosomy in at least 12 cases. A missense point mutation, at codon 49 (nucleotide 164), was seen in only 1 of the 88 patients. No homozygous deletion and no point mutation of the p16 gene was seen in AML, MDS, CLL, and myeloma. Homozygous deletion of interferon alpha genes (situated close to p16 gene in 9p21) was seen in only 3 of the 9 ALL patients with p16 gene homozygous deletion, and none of the ALL without p16 gene homozygous deletion. Our findings suggest that homozygous deletion of the p16 gene is seen in about 15% of ALL cases, is not restricted to cases with cytogenetically detectable 9p deletion, and could have a pathogenetic role in this malignancy. On the other hand, p16 point mutations are very rare in ALL, and we found no p16 homozygous deletions or mutations in the other hematologic malignancies studied.

Base Sequence↗
PubMed1995

Analysis of p16 gene deletion and point mutation in breast carcinoma.

We looked for p16 gene deletion by Southern analysis and p16 gene point mutation by single-stranded conformation polymorphism (SSCP) analysis and direct sequencing of DNA from fresh tumour samples of 35 and 33 breast carcinomas respectively. No homozygous p16 gene deletion was found in any case. A missense point mutation of the p16 gene was found in only one patient. This point mutation was absent from the patient's lymphocytes, ruling out a polymorphism or a germline mutation. These findings suggest that p16 gene alterations are rarely observed in breast carcinoma.

Base Sequence↗