Biomedical subjects

R A Stahel

Publications and source records attributed to R A Stahel.

At least 37 records · Page 2Linked to original sources

PubMed2001

Activity of a novel bcl-2/bcl-xL-bispecific antisense oligonucleotide against tumors of diverse histologic origins.

BACKGROUND: Increased expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL is involved in the development and progression of many tumors. We recently reported that the bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 induces apoptosis in lung carcinoma cells. To further assess the therapeutic potential of oligonucleotide 4625, we investigated its effect on a series of human tumor cell lines of diverse histologic origins in vitro and in vivo. METHODS: Oligonucleotide 4625-mediated inhibition of bcl-2 and bcl-xL expression in vitro was measured in breast carcinoma cells with the use of reverse transcription-polymerase chain reaction (PCR), real-time PCR, and western blotting. Cytotoxicity was assessed in several different cell lines by measurement of tumor cell growth, propidium iodide uptake, and nuclear apoptosis. The in vivo activity of oligonucleotide 4625 was determined by the inhibition of growth of established tumor xenografts in nude mice, immunohistochemical staining of Bcl-2 and Bcl-x proteins in the tumors, and western blotting of tumor lysates. Apoptosis in tumor xenografts was detected with the use of in situ TUNEL (i.e., terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling) staining. All statistical tests are two-sided. RESULTS: In breast carcinoma cells, oligonucleotide 4625 treatment reduced bcl-2 and bcl-xL messenger RNA levels in a dose-dependent manner. At 600 nM:, oligonucleotide 4625 reduced Bcl-2 and Bcl-xL protein levels to 25% (95% confidence interval [CI] = 16% to 34%) and 20% (95% CI = 14% to 26%), respectively, of the levels in untreated cells and it decreased viability in all cell lines mainly by inducing apoptosis. In vivo, oligonucleotide 4625 statistically significantly inhibited the growth of breast and colorectal carcinoma xenografts by 51% (95% CI = 28% to 74%) and 59% (95% CI = 44% to 74%), respectively, relative to those treated with control oligonucleotide 4626; it also reduced Bcl-2 and Bcl-xL protein levels and induced tumor cell apoptosis. CONCLUSION: The bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 merits further study as a novel compound for cancer therapy.

Animals↗

PubMed2001

Human leukocyte antigen G up-regulation in lung cancer associates with high-grade histology, human leukocyte antigen class I loss and interleukin-10 production.

Immune evasion in lung cancer results from both structural and functional alterations of human leukocyte antigen (HLA) class I molecules and the local release of immunosuppressive cytokines. Recent data suggest that HLA-G, a nonclassical class Ib molecule, is involved in immune evasion by tumor cells. We sought to determine whether HLA-G could contribute to immunescape in lung cancer. All of 19 tumor specimens examined demonstrated detectable membrane-bound (HLA-G1), as well as soluble (HLA-G5) isoform transcription. Nine of 34 (26%) tumors were positive by immunohistochemistry using monoclonal antibody (mAb) 4H84, recognizing all denatured HLA-G isoforms, of which six were positive using mAb 16G1, recognizing soluble HLA-G. HLA-G immunoreactivity correlated with high-grade histology, with HLA-G being preferentially expressed on large-cell carcinomas. In these patients, loss of classical HLA class I molecules was observed to associate with HLA-G protein up-regulation. Moreover, we found interleukin-10 expressed in 15 of 34 (44%) tumors, and in most of the HLA-G-positive cases (7 of 9), suggesting up-modulation of HLA-G by interleukin-10. It is conceivable that HLA-G expression in lung cancer might be one of the ways how the tumor down-regulates host immune response, in addition to interleukin-10 production and HLA class I loss.

Aged↗

PubMed2001

Persistent polyclonal B-cell lymphocytosis is an expansion of functional IgD(+)CD27(+) memory B cells.

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare disorder of unknown aetiology affecting predominantly young to middle-aged women. It is characterized by a polyclonal expansion of B cells, including typical binucleated lymphocytes, and is associated with the presence of the translocation t(14;18), involving the bcl-2 oncogene. The stage of differentiation of the B cells expanded in PPBL is not known. We analysed the immunophenotype of the expanded B-cell subset in five new patients with PPBL and found a large uniform expansion of a recently defined human memory B-cell population, IgD(+)CD27(+) memory B cells. After in vitro stimulation with interleukin 2 (IL-2) and Staphylococcus aureus Cowan strain I, B cells from PPBL patients produced high levels of IgM immunoglobulins, which is a characteristic feature of IgD(+)CD27(+) memory B cells. Using a quantitative real-time polymerase chain reaction method, we found a high frequency of the translocation t(14;18) in the range of 1000-3000 per 106 B cells in PPBL patients. In contrast, a much smaller number of cells with a t(14;18) was found in B cells from healthy individuals. Our finding that PPBL is an accumulation of memory B cells further suggests that chronic antigeneic stimulation plays an important part in the pathogenesis of this disorder. This IgD(+)CD27(+) memory B-cell population might harbour a certain number of 'physiological' t(14;18) translocations that increases as this population expands in PPBL patients and constitutes the majority of peripheral blood lymphocytes.

Adult↗

PubMed2001

Weekly x 4 induction therapy with the anti-CD20 antibody rituximab: effect on circulating t(14;18)(+) follicular lymphoma cells.

Rituximab 375 mg/m(2) weekly x 4 has been reported to induce a 60% response rate in patients with relapsed follicular lymphomas (FL). Our aim was to examine the effect of this rituximab schedule on circulating FL cells in an ongoing multicenter study. One hundred fifty-four patients with FL were examined by nested polymerase chain reaction (PCR) at baseline for the presence of t(14;18) translocation-carrying lymphoma cells in bone marrow and/or blood. Sixty-four patients (42%) had PCR-detectable t(14;18)(+) FL cells. Pretreatment characteristics of these 64 patients were as follows: one had stage I, nine had stage II, 14 had stage III, and 40 had stage IV disease. Thirty-five patients had bulky disease (> or = 5 cm) and 25 patients had an elevated serum lactate dehydrogenase (LDH) level. Bone marrow was morphologically assessed in 64 patients, and 39 of these patients had an infiltration with FL cells. Blood samples from 51 patients were available for PCR analysis between weeks 8-12 after induction therapy, and 28 of these patients (55%) were PCR negative. Paired blood and bone marrow samples were available for PCR analysis from 39 patients between weeks 8-12 after induction therapy with rituximab. Thirteen of these patients (33%) did not have PCR-detectable cells in blood and bone marrow, while 26 patients (67%) still had circulating t(14;18)(+) cells in either bone marrow (eight patients), blood (one patient), or both (17 patients). PCR negativity in blood and bone marrow in 13 patients was statistically significantly associated with partial or complete response after induction therapy with rituximab (P = 0.006). However, clearance of PCR-detectable t(14;18)(+) cells in bone marrow and/or blood could not be associated with any low tumor burden pretreatment characteristics such as stages I/II, absence of morphological bone marrow infiltration or tumor bulk of > or = 5 cm, and normal serum LDH.

Adult↗

PubMed2000

Organizing cancer genetics programs: the Swiss model.

PURPOSE: Inherited predisposition to cancer is a complex issue, and risk assessment, counseling, and management are multidisciplinary tasks. An infrastructure is needed through which clinical services may be delivered and research activities conducted. METHODS: The Swiss Institute for Applied Cancer Research (SIAK) Network for Cancer Predisposition Testing and Counseling was established in 1999. The goals of the Network are to set common standards for clinical services, to coordinate research activities, to address psychosocial and ethical issues concerning genetic counseling and testing, and to translate the knowledge gained into medical practice. RESULTS: An algorithm for genetic testing and counseling of the families studied by the SIAK Network centers has been established in a consensual process. Eight regional centers currently operate according to this algorithm. Furthermore, a proposal has been submitted for the setup of a Swiss databank for the characterization of BRCA1 and BRCA2 mutation patterns and the identification of potentially unique mutations in probands who seek genetic counseling and testing at the respective centers of the SIAK Network. CONCLUSION: Our coordinated effort will ensure state-of-the-art genetic testing and counseling services in Switzerland and will allow us to acquire knowledge for appropriate risk assessment and surveillance/prevention strategies for individuals with an inherited cancer predisposition.

Adult↗

PubMed2000

Ectopic expression of human topoisomerase IIalpha fragments and etoposide resistance in mammalian cells.

Cellular resistance to etoposide has been correlated both with reduced levels and an aberrant cytoplasmic accumulation of the drug's target, topoisomerase IIalpha (topo IIalpha). It is not known, however, whether a cytoplasmic pool of topo IIalpha is sufficient to confer drug resistance on cultured mammalian cells. In our study, we have transfected mouse fibroblasts and human 293 cells with truncated forms of human topo IIalpha fused to GFP and have examined the transformants for the subcellular localization of topo IIalpha and their resistance to etoposide. Transient transfection resulted in high-level expression of all GFP-topo IIalpha fusions tested, whereas in stably transfected cells the levels varied significantly. Transfectants expressing a central or a carboxy-terminal topo IIalpha domain (aa 428-1504, 639-1028 or 1028-1504) accumulated high levels of the fusion proteins, while only very low amounts of GFP-topo IIalpha proteins were observed in cell lines expressing constructs that retain the amino-terminus of the enzyme (aa 1-1214, aa 1-939, aa 1-611). Our results suggest that the topo IIalpha amino-terminus affects the stability of truncated forms of the enzyme in mammalian cells, perhaps due to targeted degradation. Assays that screen for cell vitality and DNA synthesis reveal no significant changes in etoposide sensitivity in transfected cells expressing high levels of cytoplasmic or nuclear localized topo II fusion proteins. Retroviral expression of a cytoplasmically anchored domain of human topo IIalpha also failed to confer drug resistance. These results suggest that a cytoplasmic pool of topo IIalpha is not sufficient to render cultured mammalian cells drug resistant.

3T3 Cells↗

PubMed2000

Bcl-xl antisense treatment induces apoptosis in breast carcinoma cells.

Upregulated expression of bcl-xL is involved in the initiation and progression of breast cancer by inhibiting tumor cell apoptosis. Here we describe the use of the 2;-O-methoxy-ethoxy antisense oligonucleotide 4259 targeting nucleotides 687-706 of the bcl-xL mRNA, a sequence that does not occur in the pro-apoptotic bcl-xS transcript, to restore apoptosis in estrogen-dependent and independent breast carcinoma cells. The antisense effect of oligonucleotide 4259 was examined on the mRNA and protein level using real-time PCR and Western blot analysis, respectively, and the induction of cell death was investigated in viability and apoptosis assays. Treatment of MCF7 cells with oligonucleotide 4259 at a concentration of 600 nM for 20 hr decreased bcl-xL mRNA and protein levels by more than 80% and 50%, respectively. This resulted in the induction of apoptosis characterized by mitochondrial cytochrome c release, decrease of mitochondrial transmembrane potential, and the appearance of condensed nuclei in approximately 40% of cells. Moreover, oligonucleotide 4259 efficiently downregulated bcl-xL expression and decreased cell growth in the breast carcinoma cell lines T-47D, ZR-75-1, and MDA-MB-231. Our data emphasize the importance of bcl-xL as a survival factor for breast carcinoma cells and suggest that oligonucleotide 4259 deserves further investigations for use in breast cancer therapy.

Apoptosis↗

PubMed2000

A novel antisense oligonucleotide targeting survivin expression induces apoptosis and sensitizes lung cancer cells to chemotherapy.

Survivin, an inhibitor of apoptosis protein, deserves attention as a selective target for cancer therapy because it lacks expression in differentiated adult tissues but is expressed in a variety of human tumors. We designed 20-mer phosphorothioate antisense oligonucleotides targeting different regions of survivin mRNA and investigated their ability to down-regulate survivin mRNA and induce apoptosis in the lung adenocarcinoma cell line A549. Oligonucleotide 4003, which targets nucleotides 23-251 of survivin mRNA, was identified as the most potent compound. As measured by real-time PCR, 4003 down-regulated survivin mRNA in a dose-dependent manner with an IC50 of 200 nM. Its maximum effect was achieved at a concentration of 400 nM, at which mRNA was down-regulated by 70%. As revealed by increased caspase-3-like protease activity, nuclear condensation and fragmentation, and trypan blue uptake, treatment with 4003 induced apoptosis and sensitized tumor cells to the chemotherapeutic agent etoposide. Oligonucleotide 4003 did not reduce the viability of normal blood leukocytes with marginal levels of survivin mRNA.

Antineoplastic Agents, Phytogenic↗

PubMed2000

Induction of apoptosis in lung-cancer cells following bcl-xL anti-sense treatment.

Over-expression of the anti-apoptotic protein bcl-xL is frequently found in lung cancer where it potentially contributes to tumor development, progression and drug resistance. To override the apoptotic block in lung-adenocarcinoma and small-cell-lung-cancer (SCLC) cells caused by over-expression of bcl-xL, an anti-sense oligodeoxynucleotide was designed targeting a sequence unique to the bcl-xL coding region and not shared by the pro-apoptotic splice variant bcl-xS. Moreover, to improve the biophysical properties of the anti-sense compound, 2;-methoxy-ethoxy modifications were made to selected deoxy-ribose residues. The resulting gapmer oligonucleotide 4259 was tested on lung-adenocarcinoma and SCLC cell lines in vitro. Treatment of the adenocarcinoma cell lines A549 and NCI-H125 and the SCLC cell lines SW2 and NCI-H69 with 600 nM 4259 reduced bcl-xL levels by 70 to 90%. In the lung-adenocarcinoma cell lines, apoptosis was induced, as indicated by caspase-3-like protease activation and nuclear condensation and fragmentation. In contrast, in the SCLC cell lines, no induction of apoptosis could be demonstrated. These findings imply that bcl-xL is a more critical survival factor for lung adenocarcinomas than for SCLC, and suggest the use of oligonucleotide 4259 for therapy of this major sub-type of lung cancer.

Apoptosis↗

PubMed2000

[High-dose chemotherapy with autologous bone marrow transplantation: 11 years' experience in Zurich].

High-dose chemotherapy with autologous bone marrow or peripheral blood stem cell transplantation has gained widespread acceptance for the treatment of certain malignancies. Since the introduction of this therapy in 1988 we have treated 272 patients. Indications for high-dose chemotherapy were high-risk large cell lymphoma and lymphoblastic or Burkitt lymphoma in first remission (73 patients), non-Hodgkin's lymphoma in chemosensitive relapse (65 patients), Hodgkin's lymphoma in relapse (52 patients), germ cell tumours with inadequate response to chemotherapy (34 patients), multiple myeloma (29 patients), and other malignancies (19 patients). Treatment mortality was 1.8%. The 3-year event-free survival and overall survival for all patients were 48 and 61% respectively. High-dose chemotherapy with autologous stem cell transplantation has become a safe procedure and is considered the treatment of choice for relapsed large cell lymphoma, relapsed Hodgkin's disease, stage II or III multiple myeloma, and germ cell tumours with inadequate response to cisplatin-based chemotherapy. In other situations, including aggressive lymphoma with risk factors, acute leucaemia or breast cancer, the superiority of high-dose over conventional chemotherapy remains to be proven. Patients with such diseases should not receive high-dose chemotherapy outside a controlled clinical study.

Adolescent↗

PubMed2000

Risk-adapted chemotherapy of germ cell tumors with carboplatin, etoposide and bleomycin for low-risk and cisplatin, etoposide and ifosfamide for high-risk patients. A single-center study.

The prognosis of germ cell tumors treated with chemotherapy depends on the presence of nonseminomatous tumor, clinical parameters based on the tumor volume and site, as well as on the level of the tumor markers AFP, betaHCG and LDH. We report here on the results of a risk-adapted approach to the chemotherapy of germ cell tumors. Patients with low-risk tumors, defined as seminomatous disease and/or nonseminomatous disease with a tumor mass <10 cm, less than 20 lung metastases, no liver, bone, or CNS metastases, and levels of AFP <1,000 IU/ml and betaHCG <10,000 IU/l, were to receive 4 cycles of carboplatin 400 mg/m(2) i.v. day 1, etoposide 120 mg/m(2) i.v. days 1-3 and bleomycin 30 IU i.v. days 1, 8 and 15 during the first 3 cycles (CEB(90)). Patients with high-risk disease were to receive 4 cycles of ifosfamide 1,500 mg/m(2) continuous infusion on days 1-4 together with mesna 1,200 mg/m(2) days 1-5, cisplatin 20 mg/m(2) i.v. days 1-5 and etoposide 100 mg/m(2) i.v. days 1-5 (VIP). Of the 60 patients treated with this risk-adapted approach, 51 had low-risk and 9 had high-risk disease. Forty-five of 51 patiens treated with CEB(90) achieved complete remission (CR), 4 achieved partial remission with marker negativity. Four patients with CR relapsed between 4 to 8 months after the start of chemotherapy. Of the 6 patients failing CEB(90), 3 were treated successfully with surgery or further chemotherapy. With a median follow-up of 52 months, the estimated cause-specific 3-year survival is 93% (95% confidence interval, CI, 80-98%). Seven of 9 high-risk patients treated with VIP achieved a CR and 1 patient relapsed. All 3 patients failing VIP had successful salvage therapy. With a medium follow-up of 63 months all patients remain alive and free of disease. Forty-six patients receiving CEB(90) were retrospectively classified to be in the good prognosis group according to the international germ cell consensus classification. Their estimated 3-year survival was 95% (CI 81-99%). We thus confirm that CEB(90) is a well-tolerated outpatient regimen with good results in good prognosis germ cell tumors. Bleomycin at a cumulative dose of 270 U might contribute substantially to the inferior effect of carboplatin as compared to cisplatin. However, in view of the results of randomized studies favoring cisplatin over carboplatin, it is not recommended to use this regimen outside a clinical trial.

Adolescent↗

PubMed2000

A novel bispecific antisense oligonucleotide inhibiting both bcl-2 and bcl-xL expression efficiently induces apoptosis in tumor cells.

Bcl-2 and Bcl-xL are inhibitors of apoptosis frequently overexpressed in solid tumors. The bcl-2 and bcl-xL mRNAs share a region of homology comprising nucleotides 605-624 and 687-706, respectively, which differs by only three nucleotides. This sequence does not occur in the proapoptotic splice variant bcl-xS. To test the possibility that oligonucleotides targeting this region have the potential to down-regulate bcl-2 and bcl-xL expression simultaneously, three 2'-O-methoxy-ethoxy-modified phosphorothioate oligonucleotides were designed. These oligonucleotides differed in the number of mismatches to bcl-2 and bcl-xL and in the number of nucleotides to which the modifications were made. The effects of these oligonucleotides on bcl-2 and bcl-xL expression, as well as their abilities to induce apoptosis, were assessed in small cell and non-small cell lung cancer cell lines expressing different basal levels of bcl-2 and bcl-xL. Although all oligonucleotides down-regulated bcl-2 and bcl-xL expression, oligonucleotide 4625, which has no mismatching nucleotides to bcl-2 but three to bcl-xL, two of which were modified by 2'-O-methoxy-ethoxy residues, showed the strongest bispecific activity on the transcript and protein level. In all cell lines this bispecific activity induced apoptotic cell death, as demonstrated by increased uptake of propidium iodide, a 10-100-fold increase in caspase-3-like protease activity, and nuclear condensation and fragmentation. This is the first report of a bcl-2/bcl-xL bispecific antisense oligonucleotide that deserves attention as a therapeutic compound in lung cancer and other malignancies in which bcl-2 and/or bcl-xL are overexpressed.

Apoptosis↗

PubMed1999

The cytochrome b5 tail anchors and stabilizes subdomains of human DNA topoisomerase II alpha in the cytoplasm of retrovirally infected mammalian cells.

DNA topoisomerase II (topo II) is the target of many anticancer drugs and is often altered in drug-resistant cell lines. In some tumor cell lines truncated isoforms of topo IIalpha are localized to the cytoplasm. To study the localization and function of individual enzyme domains, we have epitope-tagged several fragments of human topo IIalpha and expressed them by retroviral infection of rodent and human cells. We find that fusion of the topo II fragments to the hydrophobic tail of human liver cytochrome b5 anchors the fusion protein to the outer face of cytoplasmic membranes, as determined by colocalization with calnexin and selective detergent permeabilization. Moreover, whereas the minimal ATPase domain (aa 1-266) is weakly and diffusely expressed, addition of the cytb5 anchor (1-266-b5) increases its steady-state level 16-fold with no apparent toxicity. Similar results are obtained with the complete ATPase domain (aa 1-426). A C-terminal domain (aa 1030-1504) of human topo IIalpha containing an intact dimerization motif is stably expressed and accumulates in the nucleus. Fusion to the cytb5 anchor counteracts the nuclear localization signal and relocalizes the protein to cytoplasmic membranes. In conclusion, we describe a technique that stabilizes and targets retrovirally expressed proteins such that they are exposed on the cytoplasmic surface of cellular membranes. This approach may be of general use for regulating the nuclear accumulation of drugs or proteins in living cells.

Animals↗

PubMed1999

Novel approaches to the treatment of small-cell lung cancer.

Small-cell lung cancer (SCLC) is characterized by its initial responsiveness to chemotherapy and the appearance of early metastases. Although combination chemotherapy, in some instances together with radiation, has improved the prognosis of this disease, in most patients SCLC ultimately recurs in a drug-resistant form. Several new strategies for the eradication of SCLC are being explored at the preclinical level. The identification of selective target molecules on the surface of SCLC cells, together with the progress made in antibody engineering, have provided new generations of antibodies and immunoconjugates as well as growth factor antagonists and inhibitors. In addition, recent advances in understanding the biology of SCLC have stimulated new investigations searching to counter the molecular basis underlying the increased proliferation and the apoptosis deficiency of SCLC cells. This can be achieved using antisense oligodeoxynucleotides that repress the expression of growth factor receptors and anti-apoptosis genes, or by gene replacement to compensate for the loss or inactivation of tumor suppressor genes.

Antibodies, Neoplasm↗

PubMed1999

Single-agent gemcitabine: an active and better tolerated alternative to standard cisplatin-based chemotherapy in locally advanced or metastatic non-small cell lung cancer.

This randomized study was designed to determine the response rates, survival and toxicities of single-agent gemcitabine (GEMZAR) and a combination of cisplatin/etoposide in chemonaive patients with non-resectable, locally advanced or metastatic non-small cell lung cancer (NSCLC). Gemcitabine 1000 mg/m2 was given as a 30-min intravenous infusion on days 1, 8, 15 of a 28-day cycle, cisplatin 100 mg/m2 on day 1, and etoposide 100 mg/m2 on days 1 (following cisplatin), 2 and 3. Major eligibility criteria included histologically confirmed non-small cell lung cancer, measurable disease, Zubrod performance status 0-2, no prior chemotherapy, no prior radiation of the measured lesion, and no CNS metastases. One hundred and forty-seven patients were enrolled, 72 in the gemcitabine and 75 in the cisplatin/etoposide arm. Patient characteristics were well-matched across both arms. Sixty-seven gemcitabine and 72 cisplatin/etoposide patients were qualified for efficacy analysis. There were no complete responses, but 12 partial responses in the gemcitabine arm and 11 in the cisplatin/etoposide arm, for protocol-qualified response but 12 partial responses in the gemcitabine arm and 11 in the cisplatin/etoposide arm, for protocol-qualified response rates of 17.9% (95%, CI: 9.6-29.2%,) and 15.3% (95% CI: 7.9-25.7%,), respectively. Median survival times were 6.6 months (95% CI: 4.9-7.3 months) for gemcitabine and 7.6 months (95% CI: 5.4-9.3 months) for cisplatin/etoposide. The 1-year survival probability estimate was 26% for gemcitabine and 24% for cisplatin/etoposide. There were no statistically significant between-group differences in time-to-event measures, but patients in the gemcitabine arm had a greater probability of achieving a tumour response after 2 months (probability estimate: 8 vs. 0%,) and of the response lasting at least 6 months (73 vs. 45%,). Clinical and haematologic toxicity was more pronounced in the cisplatin/etoposide arm. Quality-of-life measures indicated a significant worsening of symptomatology in the cisplatin/etoposide arm for hair loss, nausea and vomiting, and appetite loss. This randomized study provides further evidence that single-agent gemcitabine is an active and effective therapy for patients with non-resectable. locally advanced or metastatic NSCLC and good performance status, and that it is better tolerated than the combination cisplatin/ etoposide.

Adult↗

PubMed1999

A prospective study of risk-adapted therapy for large cell non-Hodgkin's lymphoma with VACOP-B followed by high-dose CBV and autologous progenitor cell transplantation for high-risk patients in remission.

Several centres reported a favourable outcome after high-dose chemotherapy with autologous progenitor cell transplantation in selected patients with high-risk large cell non-Hodgkin's lymphoma in first remission. Based on these observations, we wanted to prospectively determine the outcome of a risk-adapted therapy for patients with large cell lymphoma. Patients aged 60 years or less received 12 weeks of VACOP-B chemotherapy. For high-risk patients in remission this was immediately followed by high-dose chemotherapy with cyclophosphamide, carmustine and etoposide and autologous progenitor cell transplantation. High-risk criteria were defined before the establishment of the International Index and included large cell lymphoma stage III or IV or mediastinal large lymphoma with sclerosis stage II or higher, and the presence of bulky tumours and/or an elevated LDH. 89 patients fulfilled the clinical selection criteria and were entered onto this multicentre study. 82 patients were evaluable after confirmation of large cell histology by pathology review. Of these, 51 were considered to be in the low-risk group and 31 in the high-risk group. The 3-year event-free survival for all patients was 68%. The 3-year event-free survival was 76% for the low-risk and 55% for the high-risk group (P = 0.061). Only 22/31 high-risk patients were able to receive the high-dose chemotherapy in first remission as intended. In conclusion, although our study demonstrated that a risk-adapted therapy for large cell lymphoma could be safely administered, the potential impact on outcome of the strategy chosen here is likely to be small.

Adult↗

PubMed1998

The 5'-flanking region of human CD24 gene has cell-type-specific promoter activity in small-cell lung cancer.

The human surface antigen CD24 is over-expressed in small-cell lung cancer. Here we describe the isolation, sequencing and functional characterization of the 5'-flanking region of the human CD24 gene. A sequence (accession number: Y14692) of 3.4 kb regulates the activity of a luciferase reporter gene in CD24-expressing small-cell-lung-cancer cell lines up to 1.6-fold more than the control SV40 promoter and enhancer. In contrast, little or no luciferase activity was detected in 4 non-small-cell-lung-cancer cell lines. A deletion fragment of 269 bp had maximal activity in small-cell-lung-cancer cell lines (15- to 20-fold higher than control), while activity remained 2- to 10-fold below control in non-small-cell-lung-cancer cell lines. We conclude that the CD24 promoter has a strong and cell-type-specific activity, and propose its exploitation to drive the expression of therapeutic genes in small-cell lung cancer.

Antigens, CD↗

PubMed1998

Selection and immunomagnetic purging of peripheral blood CD34+ cells for autologous transplantation in B-cell non-Hodgkin's lymphomas.

BACKGROUND: Clonogenic tumor cells in the hematopoietic progenitor cell harvest may contribute to relapse after high dose therapy for B-cell malignancies. Purging of the HPC harvest requires large amounts of anti-B-cell antibodies, whereas CD34-selection enriches self renewing HPC's but malignant cells are still detectable in many CD34+ fractions. PATIENTS AND METHODS: We examined the feasibility and safety of a CD34-selection followed by purging with anti B-cell antibodies in 11 patients with B-cell non-Hodgkin's lymphomas undergoing high-dose therapy with cyclophosphamide, BCNU and etoposide with retransfusion of autologous HPC's. RESULTS: A mean number of 340 x 10(8) mononuclear cells was used for CD34-selection and immunomagnetic purging. CD34+ cells were enriched from a mean of 1.7% (range 0.2%-4.5%) to a mean of 68% (range 49%-87%) with a mean recovery of 27% (range 15%-43%). The mean number of retransfused CD34+ cells was 1.2 x 10(6)/kg (range 0.6-2.2 x 10(6)/kg) body weight with a median of 11 days (range 10-13 days) to neutrophil recovery of 0.5 x 10(9)/l and 17 days (range 13-25 days) to platelet recovery of 50 x 10(9)/l. Mean number of intravenous antibodies and inpatient days were 8 (range 0-14) and 22 (range 19-26) respectively. Major toxicity consisted in four septicemias. CONCLUSIONS: CD34-selected and purged HPC's are safe and mediate rapid hematological recovery after high dose therapy for B-cell non-Hodgkin's lymphomas.

Antibodies, Monoclonal↗