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Biomedical subjects

R M Lemoli

Publications and source records attributed to R M Lemoli.

At least 91 records · Page 5Linked to original sources
PubMed1990

Pharmacological elimination of tumor cells contaminating normal human bone marrow using PTT-119.

In this study, we evaluated the inhibitory effects of PTT-119, a new tripeptide which is known to be a bifunctional alkylating agent, on two tumor cell lines with different origins: SK-DHL-2 (B-cell diffuse histiocytic lymphoma cell line) and RPMI 8226 (Multiple myeloma patient cell line) and compared the toxicity of PTT-119 toward normal human bone marrow granulocyte macrophage (CFU-GM), erythroid (BFU-E), and pluripotent (CFU-GEM) progenitors. Reduction of at least four logs was achieved on clonogenic myeloma cells after 1 hr of treatment with 25 micrograms/mL of PTT-119 either in the presence or absence of irradiated bone marrow (BM) cells. More than three and at least four logs of lymphoma cell kill were found after 1 hr of incubation with 25 and 40 micrograms/mL of the tripeptide, respectively. PTT-119 antitumor effects on SK-DHL-2 were only slightly affected in the presence of an excess of BM cells. BM cells treated for 1 hr with 25 micrograms/mL of PTT-119 showed a mean recovery of 4.5, 3.8, and 13.8% of CFU-GM, BFU-E, and CFU-GEM, respectively. The addition of 5- and 10-fold excesses of red blood cells (RBC) produced a slightly higher recovery of these hematopoietic progenitors. These results suggest that PTT-119 may be useful as a chemotherapeutic agent for the ex vivo treatment of bone marrow grafts.

Antineoplastic Agents↗
PubMed1990

Photoradiation methods for purging autologous bone marrow grafts.

The potential of various photoradiation therapy for the in vitro purging of residual tumor cells from autologous bone marrow (BM) transplants is discussed in this paper. The results with fluorescent dyes, Dihematoporphyrin Ether (DHE) and Merocyanine-540 (MC-540) are detailed. Following photoradiation of cells with white light, both DHE and MC-540 showed high cytocidal activity towards lymphoid and myeloid neoplastic cells, but had significantly less effect on normal granulocyte-macrophage (CFU-GM), erythroid (BFU-E) and mixed colony-forming (CFU-GEMM) progenitor cells. Acute promyelocytic leukemia (HL-60), non-B, non-T, cALLa positive acute lymphoblastic leukemia (Reh), and diffuse histiocytic B-cell lymphoma (SK-DHL-2) cell lines were exposed to different drug concentrations in combination with white light at a constant illumination rate of 50,000 lux. With DHE doses varying from 2.0 to 2.5 ug/ml and MC-540 concentrations of 15 to 20 ug/ml, clonogenic tumor cells could be reduced by more than 4 logs, when treated alone or in mixtures with normal irradiated human marrow cells. However, preferential cytotoxicity towards neoplastic cells was highly dependent on the mode of light activation. MC-540 had no substantial effect on malignant lymphoid (SK-DHL-2) and myeloid (HL-60) cells, and on normal marrow myeloid (CFU-GM) precursors, when the drug incubation was performed in the dark and followed by light exposure of washed cells. Equal doses of MC-540 (15-20 ug/ml) could preferentially eliminate tumor cells under conditions of simultaneous light and drug treatment (30 minutes at 37 degrees C). Using DHE (2.5 ug/ml), 29.3%, 46.8%, and 27.5% of normal marrow CFU-GM, BFU-E, and CFU-GEMM, respectively, were spared, following sequential drug and light exposure of cells, while simultaneous treatment reduced both normal (CFU-GM) and neoplastic cells below the limits of detection. The data from various centers is briefly discussed with special emphasis on clinical trials. Our results provide a useful model for leukemia and lymphoma cells and suggest that these phototherapy experiments can be implemented into clinical trials.

Bone Marrow↗
PubMed1990

In vitro cytotoxicity of VP-16-213 and nitrogen mustard: agonistic on tumor cells but not on normal human bone marrow progenitors.

The possible presence of tumor cells in remission bone marrow (BM) is one of the major problems for the success of autologous BM transplantation (ABMT), because the reinfusion of viable malignant cells may result in relapse. In this study we attempted the purging of the malignant cells by the use of VP-16-213 (VP-16) and nitrogen mustard (NM) either alone or in combination. Four cell lines from various hematological malignancies were utilized: SK-DHL-2 was established from a B-cell diffuse histiocytic lymphoma; RAJI was from an Epstein-Barr virus (EBV)-infected B-cell lymphoma cell line; K-562 were from a chronic myelogenous leukemia (CML) blastic crisis; and HL-60, derived from a human promyelocytic leukemia, were used in exponential growth phase. Four logs of tumor cell-elimination were observed after 1-h incubation of RAJI cells with 25 micrograms/ml of VP-16. K-562 and SK-DHL-2 cells showed a greater than 4 logs reduction after 1-h exposure to 75 micrograms/ml of VP-16, and HL-60 cell line growth was inhibited by 3.2 logs. Under the same conditions (i.e., the treatment with 75 micrograms/ml), we observed a mean recovery of 2.7% of BM granulocyte-macrophage colonies (granulocyte-macrophage colony-forming units, CFU-GM), 3.2% of erythroid (erythroid burst-forming units, BFU-E), and 2.5% of pluripotent (granulocyte erythrocyte macrophage megakaryocyte colony-forming units, CFU-GEMM) progenitors, respectively. More than 3 logs reduction of leukemia and lymphoma cell lines were reached following 1-h treatment with 1 micrograms/ml of NM. After exposure to the same concentration of the drug we obtained 2.5% CFU-GM, 1.2% BFU-E, and 2% CFU-GEMM recovery. A drug mixture containing constant doses of VP-16 (10 and 20 micrograms/ml) and NM (1 micrograms/ml) reduced HL-60 and SK-DHL-2 cell growth to undetectable levels (i.e., 4 and 5 logs elimination) in the presence of an excess of irradiated BM cells, whereas it did not further affect the recovery of the BM precursors as compared to the single drugs used alone. These results suggest that the combination of these two drugs at the selected dose level could provide a better therapeutic index (i.e., higher tumor cell killing coupled with no additional cytotoxic effect on normal BM cells) than the same chemotherapeutic agent used alone and that this mixture may be useful for the "ex vivo" treatment of BM grafts.

Bone Marrow↗
PubMed1989

Phase II study of a new alkylating agent (PTT-119) in resistant-relapsed non-Hodgkin's lymphomas.

In a phase II study we evaluated the effect and toxicity of a new alkylating agent, PTT-119, in 26 patients with non-Hodgkin's lymphomas (NHL) resistant to or relapsed after other chemotherapy. PTT was scheduled by escalating the dose from 2.0 to 3.3 mg/kg every 3 weeks. Among 21 evaluable patients with NHL, 12 (57%) showed a good response (CR + PR) to PTT-119. Tolerance was acceptably good; no major side effects related to liver, cardiac, or renal toxicity were recorded. The most commonly recorded side effects were nausea and vomiting, alopecia, and phlebitis; diarrhea and drug-related fever were rarely seen. This report indicates a potential usefulness for PTT-119, a non-cross-resistant alkylating agent, in the treatment of NHL.

Adult↗
PubMed1989

Bone marrow purging for multiple myeloma by avidin-biotin immunoadsorption.

Avidin-biotin immunoadsorption, a technique based on the high affinity between the protein avidin and the vitamin biotin, has been used to remove neoplastic plasma cells from the bone marrow of patients with multiple myeloma. Buffy coat cells obtained from 25 patients were first incubated with monoclonal antibodies (MoAb) capable of recognizing plasma cell-associated antigens (i.e., 8A, 8F6, 62B1, and cocktails of 8A plus 8F6 or 62B1), then with biotinylated goat antimouse immunoglobulin, and passed over a column containing avidin conjugated to Sepharose GMB. Both non-linked and linked cells were analyzed by immunofluorescence and morphological staining. The results showed that over 98% of plasma cells were removed by using 8A or 8F6 alone, while 99.5% +/- 0.4 SD of plasma cell purging was achieved with 2 associated MoAb. In addition, the overall recovery of committed granulocyte-macrophage (CFU-GM),* erythroid (BFU-e), and multilineage (CFU-GEMM) progenitors after column treatment ranged from 39% +/- 15 SD to 50% +/- 6 SD, from 15% +/- 2 SD to 39% +/- 7 SD, and from 16 +/- 4 SD to 64% +/- 10 SD, according to the MoAb employed. On this basis avidin-biotin immunoadsorption appears to be a suitable technique for ex-vivo manipulation of bone marrow infiltrated by neoplastic plasma cells.

Antibodies, Monoclonal↗
PubMed1989

Evidence that long-term bone marrow culture of patients with multiple myeloma favors normal hemopoietic proliferation.

Long-term bone marrow cultures (LTBMC) were initiated with marrow aspirate cells from 12 patients with multiple myeloma (MM) using the Dexter system. The myeloid and the neoplastic myeloma cell growths were evaluated for up to 6-9 weeks. Our results demonstrate the development of an adherent layer capable of supporting normal granulopoiesis with a concomitant drop in the growth of myeloma cells. The B lymphocyte monoclonal proliferative compartment was also studied with bromodeoxyuridine (Brdurd), an analog of thymidine incorporated during the S-phase, and the labeling index was calculated. The ability to form myeloma stem cell colonies in a modified plasma clot short-term assay was also evaluated. The results confirmed that the neoplastic B lineage compartment was not able to grow in Dexter's system for more than 4 weeks in 11 of 12 cases studied, with the disappearance of Brdurd-positive cells after two weeks, whereas LTBMC were able to sustain the growth of myeloid progenitors. These data indicate the potential applicability of this culture method in selecting normal hematopoietic progenitors from patients with multiple myeloma. This approach can have significant implications for aggressive treatment of patients with multiple myeloma, especially in trials involving autologous bone marrow transplantation (ABMT).

Adult↗
PubMed1989

Immunotoxins containing saporin 6 and monoclonal antibodies recognizing plasma cell-associated antigens: effects on target cells and on normal myeloid precursors (CFU-GM).

Monoclonal antibodies 8A and 62B1, recognizing plasma cell-associated antigens, were covalently linked to saporin 6, a ribosome-inactivating protein similar to the A-chain of ricin. Both immunotoxins were tested on target human cell lines U266 and Raji, on non-target K562 cell line and on myeloid CFU-GM progenitors. The cloning efficiency and viability of target cells were strongly reduced by 8A-saporin 6 and 62B1-saporin 6 immunotoxins, with an ID50 up to 200,000-fold lower than free saporin 6, whilst the K562 non-target cell line was unaffected. Normal human myeloid precursors (CFU-GM) were inhibited by immunotoxins only to a limited extent. An application of this model for autologous bone marrow transplantation in multiple myeloma patients is proposed. Since no eradication of cloning target cells was achieved by a single immunotoxin, mixtures made with different antibodies could help to reach this goal.

Animals↗
PubMed1989

Ex vivo treatment of myeloma cells by 4-HC, VP-16, LAK cells and antibodies.

To assess the usefulness of 4-hydroperoxycyclophosphamide (4-HC) and Etoposide (VP-16) as a purging agent for myeloma cells in bone marrow ex-vivo, myeloma cell lines (SK-RCS-1, RPMI-8226), lymphoma cell line (SK-DHL-2) and normal bone marrow (BM) cells were treated at different concentrations of 4-HC, VP-16. In separate experiments, LAK cells or antibodies were also used to treat the above cell lines. Clonogenic tumor cells from all three cell lines could be reduced by more than 4 logs, when treated alone or as a mixture with irradiated normal bone marrow cells at a 4-HC concentration of 60 mumol/l. Under similar conditions, approximately 1% of normal BM myeloid progenitor granulocyte-macrophage colony forming cells (CFU-GM) survived. The results with LAK cells and antibodies were also encouraging. These observations support the use of various purging methods for myeloma cells for autologous bone marrow transplantation.

Antibodies, Monoclonal↗
PubMed1989

Normal myeloid progenitors (CFU-GM) in multiple myeloma: a preliminary study in view of autologous BMT.

Normal granulocyte-macrophage precursors (CFU-GM) were studied in 65 multiple myeloma patients by means of culture assays. The patients were divided into separate groups on the basis of previous therapy (i.e. analysis performed at diagnosis or after chemotherapy), time elapsed from the last therapy (i.e. more or less than 1 month) and clinical features of the disease (i.e. tumor stage, immunoglobulin type, bone marrow plasma cell infiltration). The results were evaluated by Wilcoxon rank sum test and linear regression analysis. There was no statistical difference in CFU-GM cloning efficiency or in the number of CFU-GM/ml of bone marrow, even though a larger CFU-GM recovery was found in patients evaluated at diagnosis or at least 1 month or more from previous chemotherapy. In addition, no correlation was demonstrated between bone marrow plasma cell percentage and CFU-GM cloning efficiency. This finding was confirmed by the number of myeloid bone marrow cells in S-phase, assessed by the bromodeoxyuridine labeling index, which showed similar results in patients with different degrees of plasma cell infiltration. In conclusion our data indicate that the granular-monocytic lineage keeps its cell-line potentiality regardless of the degree of marrow plasma cell infiltration and the type of therapeutic approach. These data suggest that autologous bone marrow transplantation might be feasible even in patients with a large neoplastic infiltration.

Adult↗
PubMed1988

In situ staining of bromodeoxyuridine positive cells in normal and neoplastic colony-forming units grown on plasma clots.

Bromodeoxyuridine, an analogue of thymidine, can be detected by means of monoclonal antibodies and utilized as a marker of the S-phase of the cell cycle. In this paper a method for the detection of the labeling index of normal and neoplastic colony-forming units (CFU) growing in plasma clot semisolid medium is described and preliminary results on the cell cycle of 7th and 14th CFU granulocyte-macrophage are discussed.

Blood Coagulation↗
PubMed1988

Improvement of human myeloma stem cell growth in a liquid culture system supplemented with phytohemagglutinin.

A highly efficient cloning system for in vitro myeloma colony growth could be valuable for screening antineoplastic agents in resistant patients and for testing the effects of purging methods in the context of autologous bone marrow transplantation. In this paper we report the results of experiments intended to improve the myeloma cloning system in plasma clot originally described by Ludwig et al. We tested the effects of the addition of phytohemagglutinin (PHA), coupled with a transformation of the original plasma clot method into a liquid culture system. A statistically higher number of myeloma colonies was observed in the liquid system in the presence of PHA (20 cases, median 84.5 vs. 9.5; p = 0.005), whereas a single variant (either PHA alone or liquid system alone) did not determine any significant growth variation. The increase in the cloning efficiency was evident even in the cases characterized by low bone marrow plasma cell infiltration, suggesting that this method is suitable for the described purposes.

Bone Marrow Cells↗
PubMed1988

Sensitivity of Ph 1 + CFU-GM to human recombinant interferon alpha and gamma alone and in combination.

The in vitro effect of human recombinant interferon alpha (IFN) alone and in combination were studied on granulomonocytic colony forming units (CFU-GM) from the peripheral blood of 10 Ph 1+ chronic myeloid leukemia (CML) patients and from the marrow of 5 normal or non-leukemic subjects. alpha- and gamma-IFN alone determined a slight inhibition on colony growth with a preferential effect on "pure" macrophagic colonies. At maximum concentration (10(4) U/ml) leukemic colony inhibition was 46 +/- 34% for alpha IFN and 43 +/- 19% for gamma IFN. Culture growth with alpha + gamma IFN in combination were significantly inhibited (up to 96 +/- 4%) with a concentration-related effect. Similar results were obtained with normal CFU-GM. The synergism that was found in vitro is probably relevant for the in vivo therapeutic effects of these compounds in CML and suggest that the combination is worth testing in vivo.

Drug Therapy, Combination↗
PubMed1988

Autologous bone marrow transplantation in patients with non-Hodgkin's lymphoma: comparison of different parameters in predicting the kinetics of haematological recovery.

We analysed the kinetics of haematological recovery after autologous bone marrow transplantation (ABMT) in 31 patients with non-Hodgkin's lymphoma, of whom 14 had received chemotherapy and 17 had received no chemotherapy before marrow harvesting. The time for recovery of polymorph (PMN) and platelet numbers was assessed in relation to patient's sex, age, the numbers of mononuclear cells (MNC) and of granulocyte-macrophage colony-forming cells (CFU-GM) reinfused, the therapy before harvesting and the conditioning regimens. The results showed that the most important factor influencing the speed of haematological recovery was therapy before marrow collection; recovery was faster in patients not treated before harvesting than in those treated. The mean day for PMN recovery to 0.5 x 10(9)/l was 14.6 vs 21.8 (p less than 0.001); the mean day for platelet recovery to 50 x 10(9)/l was 16.5 vs 44.4 (p less than 0.00002). The other parameters assessed did not correlate with the kinetics of haemopoietic recovery. We conclude that NHL patients who undergo ABMT without chemotherapy prior to marrow harvest have rapid haematological recovery, which suggests that better timing of the harvest could be of value in the management of NHL patients for whom 'reinforcement' with ABMT is scheduled.

Adolescent↗
PubMedDate not supplied

Negative selection of autologous peripheral blood stem cells.

The use of chemotherapy and/or haematopoietic growth factor-mobilized peripheral blood stem cells (PBSC) has been shown to induce a more rapid haematopoietic recovery than the reinfusion of bone marrow (BM)-derived haematopoietic cells, thus reducing the morbidity and mortality of autologous stem cell transplantation (ASCT). PBSC collections were initially believed to have a lower incidence of tumour cells involvement than BM harvests. However, recent studies have shown that mobilized blood cell products of cancer patients eligible for autografting are frequently contaminated with tumour cells. Whereas positive selection of haematopoietic CD34+ stem cells has been largely used as a means of indirect purging of circulating CD34+ neoplastic cells, few groups have addressed the issue of tumour cell removal by direct targeting of cancer cells using physical or pharmacological strategies. In this chapter we review the available data concerning the contamination of tumour cells in PBSC collections from cancer patients, the functional and kinetic characteristics of primed CD34+ cells which may affect the haematopoietic toxicity of purging procedures developed to eliminate the minimal residual disease (MRD) from BM samples, and the preclinical and clinical results of the selective killing of residual tumour cells from leukaphereses. The limited amount of data published so far do not allow any firm conclusion on the clinical usefulness of purging protocols. Nonetheless, the successful extension of ex vivo purging to PBSC collections may improve the feasibility of randomized studies aimed at determining the importance of tumour-free autografts.

Antigens, CD34↗
PubMedDate not supplied

Dendritic cell differentiation from hematopoietic CD34+ progenitor cells.

Dendritic cells (DC) are the most powerful antigen presenting cells (APC) and play a pivotal role in initiating the immune response. In light of their unique properties, DC have been proposed as a tool to enhance immunity against infectious agents and in anticancer vaccine strategies. In the last few years, the development of DC has been extensively investigated. The present paper summarizes the most recent findings on the differentiation of myeloid DC from hematopoietic CD34+ progenitors and methods for DC generation in vitro. A better understanding of DC function has important implications for their use in clinical settings.

Antigens, CD34↗