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Biomedical subjects

R Foa

Publications and source records attributed to R Foa.

At least 55 records · Page 3Linked to original sources
PubMed1994

Transduction of the IL2 gene into human acute leukemia cells: induction of tumor rejection without modifying cell proliferation and IL2 receptor expression.

BACKGROUND: Previous studies have suggested that some of the limitations associated with the administration of high-dose exogenous interleukin 2 (IL2) may be overcome, at least partly, by cytokine gene transfer modalities. These findings have prompted investigations into whether human tumor cells may be transduced with the IL2 gene and whether tumor cell lines could be engineered to release IL2. PURPOSE: The purpose of this study was to evaluate the possibility of inducing a productive transfer of the IL2 gene into human acute leukemia cells and to assess the phenotypic and proliferative changes generated in the engineered cells, as well as their tumorigenic potential in nude mice. METHODS: Three retroviral vectors (DC/TK/IL2, DC/AD/R/IL2, and N2/CMV/IL2) carrying the IL2 gene were used to transduce three human leukemic cell lines: K562 and U937 (myeloid) and ST4 (lymphoid). Messenger RNA expression of the IL2 gene was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) and productive IL2 release using a human IL2 assay and an enzyme-linked immunosorbent assay kit. The expression of the p55 (alpha) and p75 (beta) chains of the IL2 receptor were determined by RT-PCR and indirect immunofluorescence. The kinetics of in vitro growth and proliferation of parental and engineered cells were also measured. Parental and IL2 gene-transduced ST4 lymphoblasts were injected into immunosuppressed nude mice that had their tumors measured twice weekly. RESULTS: The productive insertion of the IL2 gene was achieved in all three cell lines studied. The amounts of IL2 constitutively released by the engineered neoplastic cells ranged between 1 and 11 U/mL of IL2 produced from 10(6) cells in 72 hours. A fivefold increase in IL2 production was obtained in ST4 cells by further limiting dilution cloning of the bulk-infected cells. The stable integration of the IL2 gene did not modify the phenotype of the leukemic cells, the expression of the IL2 receptor alpha and beta chains and of several cytokine genes, or the kinetics of in vitro growth and proliferation. In nude mice injected with various IL2-producing ST4 clones, tumor growth associated inversely with the amounts of IL2 secreted by the leukemic cells. CONCLUSIONS: The results of this study demonstrate that the IL2 gene can be productively transduced into human myeloid and lymphoid leukemic cells without modifying their phenotypic and proliferative properties and that this transduction leads to a reduced or abrogated in vivo tumorigenic potential.

Acute Disease↗
PubMed1994

Taxol (paclitaxel): a novel anti-microtubule agent with remarkable anti-neoplastic activity.

Taxol (paclitaxel), an anti-microtubule agent extracted from the needles and bark of the Pacific yew tree Taxus brevifolia, has shown a remarkable anti-neoplastic effect in human cancer in phase I studies and early phase II and III trials thus far conducted. This has been reported primarily in advanced ovarian and breast cancer, although significant activity has also been documented in small-cell and non-small-cell lung cancer, head and neck cancers, and with lower activity in metastatic melanoma. The clinical utilization of Taxol had been previously somewhat restricted by its limited availability, a limitation that has recently been overcome by combined efforts of pharmaceutical, agricultural, and governmental agencies. In this review we shall address the pre-clinical data which have led to the use of Taxol in man, the main clinical results thus far obtained, the toxicities associated with its use, current ongoing trials and future clinical directions of this promising agent.

Animals↗
PubMed1994

Interleukin-2 and gene therapy in the management of acute lymphoblastic leukaemia.

The overall unfavourable prognosis of adult acute leukaemia patients has prompted the search for alternative therapeutic strategies. Probably the most sought challenge, which over the years has been met by consistent disillusion, has been immunotherapy. With little doubt the goal of stimulating the immune system of the host in the hope of controlling or eradicating residual disease following more conventional ablative regimens, remains conceptually a highly desirable approach. During the last few years an innovative strategy, based on the in vitro demonstration that IL2 is capable of inducing a previously unrecognized cytotoxic function directed against primary tumours and named LAK, has been applied with some success in solid tumour patients. Here, we shall review the pre-clinical data which indicate that IL2-based immunotherapy may be employed also in the management of patients with acute leukaemia. Clinical data which support a possible in vivo antileukaemic effect of IL2 are presented. The clinicohaematological modifications, as well as the biological modulations induced in the patients following the administration of IL2 are also discussed. In view of the recent demonstration that the IL2 gene can be successfully transduced into human neoplastic cells, we finally discuss the rationale of gene transfer approaches in an attempt to overcome some of the limitations associated with the administration of high doses of exogenous IL2.

Adult↗
PubMed1994

Expression of the IL2 receptor alpha, beta and gamma chains in hairy cell leukemia.

The expression of the interleukin 2 (IL2) receptor chains was investigated by immunofluorescence and mRNA analysis in typical and variant hairy cell leukemia (HCL) cases. While typical hairy cells express both the alpha and the beta chains, variant HCL express the IL2 receptor beta chain on the surface membrane but not the alpha chain. Both typical and variant HCL have mRNA transcript of the p64 molecule (gamma chain). In B-cell chronic lymphocytic leukemia (B-CLL), EBV-transformed lymphoblastoid cell lines and normal B lymphocytes the expression of the IL2 receptor alpha and beta chains is very weak or negative. Furthermore, in B-CLL the IL2 receptor gamma chain shows a weaker expression compared to HCL. Both classic and variant HCL cases appear capable of proliferating in the presence of exogenous IL2, though the proliferative response of variant HCL appears lower than that of typical cases. Since in variant HCL the IL2 receptor alpha chain could not be induced by different stimuli, it appears that the CD25 antigen may not be essential in the process of IL2-promoted growth, while p75 and p64 play a primary role in IL2 activation. Taken together, it is suggested that the expression of IL2 receptors is up- or down-regulated during the process of B-cell lineage activation and differentiation.

Leukemia, Hairy Cell↗
PubMed1994

Cytokine gene therapy in oncology.

Over the last few years the possibility of introducing foreign material into the genome of host cells has become technically feasible. This has opened a new era in the treatment of congenital disorders, but has also offered potential innovative avenues in the management of cancer patients. Here, we shall discuss how cytokine genes may be successfully transduced into the DNA of different experimental tumours and how through this approach the tumorigenicity of the neoplastic cells may be abrogated. Emphasis will be given on the demonstration that following cytokine gene transfer, namely with the interleukin 2 (IL-2) gene, two of the primary goals of an optimal immunotherapeutic approach, i.e. anti-tumour specificity and memory, may be achieved. Attention will be focused, in particular, on the results so far obtained, as well as on ongoing studies, with human tumour cells engineered to release different cytokine genes. The design and activation of the first clinical protocols aimed at treating advanced cancer patients with cytokine gene-transduced neoplastic cells will also be discussed, together with other strategies of genetic engineering currently under investigation.

Animals↗
PubMed1993

Phenotypic analysis of hairy cell leukemia: "variant" cases express the interleukin-2 receptor beta chain, but not the alpha chain (CD25).

Hairy cell leukemia (HCL) is a B-cell chronic lymphoproliferative disorder in which the pathologic cells show a strong expression of CD25 (interleukin-2 [IL-2] receptor alpha chain or p55). "Variant" cases of HCL, characterized by hyperleukocytosis, neoplastic elements with a prominent nucleolus and a higher nucleo/cytoplasmic ratio, and an easily obtained bone marrow aspirate, lack surface CD25 determinants. Limited information is available on the expression of the IL-2 receptor beta chain (p75) on normal and neoplastic B cells. In this study, we have assessed by immunofluorescence and mRNA analysis the presence of the IL-2 receptor alpha and beta chains on 12 cases of classic HCL, as well as on 3 variant cases. The results obtained show that, while the alpha chain of the IL-2 receptor is present only on classic HCL, the IL-2 receptor beta chain (p75) is expressed on both the classic and variant form. Unlike hairy cells, only 8 of the 15 B-cell chronic lymphocytic leukemia cases tested showed a weak expression of the p75 antigen on a small proportion of cells. Purified B lymphocytes from normal healthy controls, as well as Epstein-Barr virus-transformed lymphoblastoid cell lines, showed a weak staining for the p75 determinant, while being CD25-. The results of this study suggest that the expression of the alpha and beta chains of the IL-2 receptor appears to be upregulated or downregulated during the process of B-cell-lineage activation and differentiation.

Adult↗
PubMed1993

Heterogeneous immunoglobulin gene rearrangement in a B-chronic lymphocytic leukemia progressing into non-Hodgkin lymphoma (Richter syndrome).

BACKGROUND: The relationship between chronic lymphocytic leukemia (CLL) and supervening non-Hodgkin lymphoma is debated, as is whether a particular genomic pattern is related to the emergence of the terminal lymphoma. To investigate these features, the molecular organization of the immunoglobulin (Ig) gene region in a case during both the B-CLL and Richter transformation phase was studied. METHODS: B-CLL and non-Hodgkin lymphoma cells were processed for Southern blot analysis of Ig heavy- and light-chain gene configuration. RESULTS: Molecular studies of B-CLL cells revealed the presence of a single Ig heavy-chain rearrangement with both kappa and lambda light-chain rearranged genes, which was consistent with the occurrence of multiple mutational events during the development of the B-CLL clone. Molecular analysis of the lymphoma DNA showed new Ig heavy- and kappa light-chain rearrangements in addition to the original ones related to the CLL phase, indicating that the lymphoma tissue consisted of two genotypically distinct populations of cells. CONCLUSIONS: On the basis of the overall molecular configuration, this heterogeneous pattern of Ig gene rearrangement was interpreted as an inherent genetic instability of the CLL clone, in which multiple mutational events allowed a selective pressure toward more aggressive subclones, resulting in the emergence of the terminal lymphoma.

Antigens, CD↗
PubMed1993

Preferential clustering of chromosomal breakpoints in Burkitt's lymphomas and L3 type acute lymphoblastic leukemias with a t(8;14) translocation.

We have analyzed the type of MYC/IG heavy-chain locus (IGH) rearrangement present in 15 patients affected by t(8;14)-positive primary Burkitt's lymphoma or acute lymphoblastic leukemia of the L3 type in an attempt to map in detail the locations of the chromosome 8 and chromosome 14 breakpoints. The almost constant position of the chromosome 8 breakpoint (within or immediately 5' of the MYC gene) together with two distinct clusters of breakpoints on chromosome 14 resulted in two main types of MYC/IGH (present in 12 of 15 cases). In the first type (six cases), the MYC gene or at least its coding portion was joined with the JH region on chromosome 14, whereas in the second, present in another six cases, the MYC gene and the C alpha I region were juxtaposed. Physical linkage between the translocated MYC and a known enhancer element of the IGH locus is the common feature in the two types of rearrangement, suggesting that a high-level constitutive expression plays a prominent role in MYC activation. Interestingly, the chromosome 14 break site within the switch alpha 1 region, which has been only occasionally described in other cases, is present in 40% of our patients, suggesting the existence of preferential breakpoint cluster regions in cases of similar geographic origin.

Adolescent↗
PubMed1993

Interleukin 2 treatment in acute myelogenous leukemia.

Significant clinical responses obtained with interleukin 2 (IL-2) in solid tumors such as renal cell cancer and malignant melanoma prompted the use of this immunomodulatory drug to verify its activity in hematological malignancies. Several preclinical experiments showed an activity of IL-2 against leukemic cell lines in cultures, particularly in acute myeloid leukemia (AML), while only episodically a proliferative stimulus of IL-2 on the growth of leukemic blasts has been observed. Based on these preclinical studies, in the past five years several phase I-II clinical trials have verified IL-2 activity in AML in advanced phase, both in patients with active disease and in patients in further complete remission (CR). Data obtained are difficult to evaluate due to the low number and the heterogeneity of patients treated, but encouraging results have been reported in patients with "limited" disease (bone marrow blastosis < 30%), showing an antileukemic activity of IL-2 alone. Different international phase III trials are ongoing in AML patients in I CR after autologous bone marrow transplantation (Roussel-Uclaf, Romainville, France) and in II CR after conventional chemotherapy (Roche SpA, Milan, Italy) to verify the efficacy of IL-2 in reducing the risk of relapse and prolonging disease-free survival.

Adolescent↗
PubMed1993

Does interleukin-2 have a role in the management of acute leukemia?

PURPOSE: To discuss the possibility that interleukin-2 (IL-2)-based immunotherapeutic protocols may have a role in the management of acute leukemia. DESIGN: The preclinical results that have led to the clinical use of IL-2 in acute leukemia will be reviewed. The clinical data obtained with the administration of IL-2 to acute leukemia patients in different phases of their disease will be discussed, together with the clinicohematologic and immunologic modifications induced following the infusion of IL-2. Finally, the possibility that limitations associated with the exogenous administration of high-dose IL-2 may be circumvented by engineering techniques aimed at inserting the IL-2 gene directly into the tumor cells, will be addressed. RESULTS: The data indicate that high-dose IL-2 may be administered to acute leukemia patients. Toxicity, recorded in all patients, appears to be controllable using a continuous intravenous (i.v.) infusion protocol based on a daily dose-escalating administration. Complete remissions have been documented in acute myeloid leukemias (AMLs) with a limited, but detectable proportion of residual marrow blasts. Numerous phenotypic and functional changes have been recorded within the immune system of the host. Using retroviral vectors, the IL-2 gene may be productively transduced into human acute leukemia cell lines. CONCLUSION: IL-2 appears to represent a therapeutic option for AML patients with limited/minimal residual disease. The results of the ongoing randomized trials in patients in first or second remission are awaited.

Acute Disease↗
PubMed1992

IL2 treatment for cancer: from biology to gene therapy.

In this review we shall discuss the biological rationale and the clinical findings obtained using Interleukin 2 (IL2)-based immunotherapy in the management of cancer patients. Objective and long-lived clinical responses have been documented in a proportion of cases, particularly renal cell carcinoma, melanoma and acute myeloid leukaemia. Though encouraging, the clinical use of IL2 has so far been limited by toxicity, as well as by the heterogeneous and unpredictable responses and by the lack of specific anti-tumour effect. These considerations have led to the belief that more sophisticated technologies aimed at introducing the IL2 gene into the neoplastic cells may potentially overcome some of the limitations coupled to the in vivo infusion of high doses of IL2. The data accumulated in animal models and, more recently, also with human tumour cells indicate that the IL2 gene may be successfully inserted into neoplastic cells. The constitutive secretion of IL2 by the tumour cells leads to a reduced or abrogated tumorigenicity in several different tumour models. The evidence that in some experimental tumours the transduction of the IL2 gene into the neoplastic cells may elicit a specific cytotoxic response and confer anti-tumour memory, suggests that vaccination protocols based on this innovative strategy may represent a potential new tool in the management of cancer patients.

Animals↗
PubMed1992

Unique genotypic features of infant acute lymphoblastic leukaemia at presentation and at relapse.

Acute lymphoblastic leukaemia (ALL) of infants aged less than 1 year represents a group of patients with peculiar biological features, poor response to therapy and unfavourable prognosis. In order better to characterize this type of leukaemia, we have investigated the immunoglobulin (Ig) and T-cell receptor (TCR) genes configuration of 21 infants with ALL, and compared the genotypic features with the phenotypic and karyotypic data, as well as with the clinical outcome. All cases had a pre-B phenotype; 12 (57%) of them were pre-pre-B ALL (CD10-, CD19+). Six of the 16 cases evaluated (38%) displayed chromosomal abnormalities; five had the typical translocation t(4;11)(q21;23). Eleven cases presented with a white blood cell count greater than 100 x 10(9)/l. The clinical course was unfavourable in 14 patients. The genotype of this group of ALL revealed several peculiarities. (1) Of the 21 cases, six (29%) displayed a multiple rearrangement pattern at the IgH locus. (2) In three cases (15%), the light chain genes were rearranged. (3) The TCR beta and gamma genes were rearranged in only one case (one case at the TCR beta and one at the TCR gamma locus). (4) The TCR delta chain was rearranged in eight cases (40%) and rarely deleted; the rearrangements observed were those most frequently observed in B cell-precursor ALL. Two cases were evaluated both at presentation and at relapse. While the immunophenotype had remained unmodified, comparison of Ig heavy chain gene rearrangements revealed clonal variations in both cases. Taken together, these findings further underline the biological peculiarities of infant ALL compared to ALL which occurs in older children and in adults, and stress the need of differentiated and aggressive therapeutic approach for these patients.

Antigens, Neoplasm↗
PubMed1992

Phenotypic and genotypic switch in Philadelphia-positive, BCR-positive blast crisis of chronic myeloid leukemia.

We report a case of Ph1-positive, bcr-positive chronic myeloid leukemia blast crisis (CML-BC) which at presentation showed a mixed myeloid/B-lymphoid immunophenotype along with TdT positivity and, at the molecular level, an oligoclonal rearrangement of the immunoglobulin heavy chain (IgH) gene region. After obtaining a successful remission, at the time of relapse the patient underwent a phenotypic and genotypic switch from mixed to myeloid phenotype, characterized by the loss of the lymphoid markers and TdT expression and by a germline configuration of the IgH gene region. The same bcr rearrangement was, however, found in both phases of the disease, supporting the suggestion of a true phenotypic and genotypic conversion. This report confirms that the neoplastic event in CML may take place at an early multipotent stem-cell level, prior to a well-defined phenotypic and genotypic lineage expression. Moreover, it is suggested that different factors (chemotherapy? growth factors?) may have either eradicated the bcr+/IgH+ clone and promoted the growth of bcr+/IgH- leukemic cells or, alternatively, supported the lymphoid differentiation program and induced a myeloid lineage shift.

Adult↗
PubMed1992

Constitutive production of tumor necrosis factor-alpha in hairy cell leukemia: possible role in the pathogenesis of the cytopenia(s) and effect of treatment with interferon-alpha.

PURPOSE: In view of the pleomorphic role cytokines play in human lymphoproliferative disorders, we investigated the possible involvement of tumor necrosis factor-alpha (TNF) in hairy cell leukemia (HCL). PATIENTS AND METHODS: The levels of TNF were measured in the serum of untreated patients, and in the culture supernatants of unstimulated and stimulated enriched hairy cells (HC). Furthermore, the presence of TNF mRNA transcripts in HC was analyzed. The possibility that HC could inhibit the in vitro growth of normal erythroid progenitors via the release of TNF was also investigated. Finally, in an attempt to correlate the circulating levels of TNF with the course of the disease, these were retested during and after treatment with interferon-alpha (IFN). RESULTS: Significantly increased levels of TNF were found in the sera of untreated HCL patients compared with normal control sera were seen from patients with other diseases (P less than .001), with values greater than 10 pg/mL in 21 of 42 samples tested. A significant decrease (P less than .01) of TNF levels was recorded following IFN-2a administration in 16 cases with detectable pretreatment serum levels of TNF. In two cases, an increase in TNF values was associated with persistence or progression of disease. The likelihood that the circulating levels of TNF were caused by the pathologic cells is supported by the evidence that purified HC may release TNF spontaneously. The values can be markedly increased following in vitro activation with the phorbol ester 12-0-tetradecanoylphorbol-13 acetate (PMA), with B-cell growth factor (BCGF), and, to a further extent, with the combination of PMA and BCGF. Furthermore, the constitutive mRNA for TNF was found in seven of eight HC samples analyzed. Although supernatants of enriched HC, were capable of reducing the growth of normal bone marrow erythroid progenitors by 50%, duplicate experiments using an anti-TNF antibody produced an almost complete disappearance of the inhibitory effect. CONCLUSION: The results of this study suggest that TNF plays an important role in the pathogenesis of the cytopenia(s) characteristically associated with HCL.

Adult↗
PubMed1992

Characterization of EBV-positive lymphoblastoid cell lines obtained from HIV seropositive patients with or without lymphomas.

Epstein-Barr-virus- (EBV-) positive lymphoblastoid cell lines (LCLs) spontaneously arising in vitro were obtained from the peripheral blood of six HIV-seropositive patients and from the peripheral blood and the bone marrow of one patient (LAM) with AIDS and lymphoma. The LCLs from HIV-seropositive patients had phenotypic, cytogenetic, and biological characteristics indistinguishable from those of normal LCLs obtained by infecting B cells with EBV in vitro. The LCLs from LAM patient comprised composite cell populations. Cloning analysis and cell fractionation procedures showed that, beside normal EBV-infected cells, these lines contained a malignant subset population characterized by c-myc rearrangement, abnormal karyotype, and a surface phenotype similar to that of Burkitt's lymphoma cells. Analyses of Ig heavy chain and c-myc oncogene loci showed that these malignant cells were the progeny of a single precursor. Nevertheless, these cells had heterogeneous EBV-fused termini, a finding which indicates that EBV infection followed c-myc rearrangement.

Blotting, Southern↗
PubMed1992

Has IL2 a role in the management of minimal residual disease for acute leukemia?

Based on pre-clinical findings and on more recent preliminary in vivo data it has been suggested that immunotherapy with Interleukin 2 (IL2) may be employed in the treatment of acute leukemia patients. Here we shall discuss the biological and clinical observations which indicate that this innovative therapeutic approach may play a role in the management of minimal residual disease.

Acute Disease↗