bcl-2 plays a critical role in growth and in spontaneous or induced apoptosis in myeloma cell lines

The role of bcl-2 in spontaneous and drug-induced apoptosis in multiple myeloma (MM) is not yet established, particularly since the frequency of t(14:18) in MM is relatively low. In recent studies, we have investigated the steady-state levels of bcl-2 mRNA transcripts and bcl-2 protein in 8 MM cell lines and found inverse correlation between the levels of bcl-2 and sensitivity to dexamethasone (DEX)-induced apoptosis. Moreover, we have shown that bcl-2 was further down-regulated in DEX sensitive cell lines, but not in DEX resistance cell lines, in the course of DEX-induced apoptosis (Int J Oncol 8: 719-726, 1996). Herein, we report the results of transfection studies of 2 DEX sensitive MM cell lines, expressing relatively low levels of bcl-2, with a bcl-2 inducible gene construct expressed under the control of lac repressor operon. Thus, switching-on of bcl-2 by IPTG resulted in increased bcl-2 protein in the cells, enhancement of cell growth, and a decrease in spontaneous apoptosis, concomitant with increased resistance to DEX. Switching-off of bcl-2 protein expression by removal of IPTG resulted in restoration of sensitivity to DEX-induced apoptosis. We, therefore, conclude that bcl-2 plays a central role in cell growth and in spontaneous and induced apoptosis in MM cell lines.

bcl-2 plays a major role in resistance to dexamethasone induced apoptosis in multiple myeloma cell lines

The role of bcl-2 in protection against apoptosis is well established in a great variety of cells and has become a hallmark of drug-resistance in many tumor cell lines, notably in lymphomas and leukemias. However, the role of bcl-2 in spontaneous and drug induced apoptosis in multiple myeloma (MM), is not yet established, particularly since the frequency of t(14:18) in MM is relatively low. We have recently studied the steady-state levels of mRNA transcripts for bcl-2, bar and P53 in 8 MM cell lines and found inverse correlation between the levels of bcl-2 mRNA transcripts and sensitivity to dexamethasone (DEX) induced apoptosis. Moreover, we have also shown that mRNA transcripts for bcl-2 were further down-regulated in 2 DEX sensitive cell lines in the course of DEX induced apoptosis, whereas mRNA transcripts for bcl-2 were unchanged in 2 DEX-resistant MM cell lines (Int J Oncol 8: 719-726, 1996). In this study, we determined the steady-state levels of bcl-2, P53 and bar proteins in 4 myeloma cell lines, and the levels were correlated with sensitivity to DEX induced apoptosis. Two cell lines (HS-Sultan and ARH-77) expressed relatively high levels of bcl-2 protein and were highly resistant to DEX induced apoptosis. Two cell lines (8226 and ARP-1) expressed relatively low levels of bcl-2 protein, and were 2-3 logs more sensitive to DEX. In contrast, the levels of bar protein were similar in all cell lines tested. The steady-state levels of P53 protein varied among the various cell lines but did not correlate with resistance to DEX. Induction of apoptosis in the DEX sensitive cells resulted in an early down-regulation of bcl-2 and P53 protein, whereas the levels of bar protein were only slightly decreased. In contrast to the DEX sensitive cell lines, the levels of bcl-2, bar and P53 proteins in the DEX resistant cell lines were unchanged during 72 h of treatment with DEX. Thus, the changes in the protein levels are in good agreement with the changes reported earlier for mRNA transcript of these oncogenes.

The role of p53, bcl-2 and bax network in dexamethasone induced apoptosis in multiple myeloma cell lines

The role of bcl-2 in protection against apoptosis is well established in a great variety of cells and has become a hallmark of drug-resistance in many tumor cell lines, notably in lymphomas and leukemias. Conflicting results have been reported as for the role of bcl-2 in spontaneous and drug induced apoptosis in multiple myeloma (MM), although high expression of bcl-2 was observed, in spite of relatively low frequency of t(14:18). We, therefore, decided to conduct a detailed study of the role of the bcl-2/bax/p53 network in dexamethasone (DEX) induced apoptosis in MM cells. Eight myeloma cell lines were screened for their expression of mRNA transcripts for p53, bcl-2 and bax, and the levels were correlated for sensitivity to DEX induced apoptosis. Two cell lines (HS-Sultan and ARH-77) expressed relatively high levels of bcl-2 transcripts, and were highly resistant to DEX induced apoptosis (up to 10 mu M). Two cell lines (8226 and ARP-1) expressed relatively low-levels of bcl-2 mRNA transcripts, and were highly sensitive to DEX (ID50= 0.1 mu M, at 24-48 h). Fax mRNA transcripts were abundant, were expressed ubiquitously in all cell lines, and, thus, did not correlate with sensitivity to DEX. The level of expression of mRNA transcripts for p53 varied among the various cell lines, and did not always correlate with resistance to DEX. Induction of apoptosis in 8226 and ARP-1 cells (DEX sensitive) resulted, within 24 h, in a transient but marked down-regulation of mRNA transcripts for bcl-2 and p53, whereas the level of expression of bax mRNA transcripts were unchanged, except for ARP-1 cells (lacking p53), where slight down-regulation of mRNA transcripts for bax, was observed. In contrast to the DEX sensitive cell lines, the level of expression of bcl-2, bax and p53 mRNA transcripts in the DEX resistant cell lines, were unchanged during 72 h of treatment with DEX (up to 10 mu M). We, therefore, conclude that bcl-2 and perhaps p53 are involved in resistance to DEX in myeloma cell lines.

Differential expression and subcellular-localization of protein-kinase-C, alpha, gamma, delta, xi and zeta isoforms in agf T-cells - modification during pma-induced differentiation

The steady-state level and translocation of the protein kinase C (PKC) isozymes during the early stages of phorbol 12-myristate 13-acetate (PMA)-induced differentiation, was followed in AGF cells by Western blot analysis of various cell fractions, immunofluorescence staining and by confocal microscopy. By Western blot analysis, uninduced AGF cells express four PKC isoforms, PKC-alpha, PKC-gamma, PKC-epsilon and PKC-zeta with no expression of PKC-beta or PKC-delta. PKC-alpha was exclusively localized to the cytosol, whereas PKC-epsilon was localized predominantly in the cytosol. PKC-gamma and PKC-zeta were found in the cytosolic, as well as in the nuclear and the membrane fractions. Following stimulation with PMA from 15 min to 24 h, cytosolic PKC-alpha did not translocate to the membrane or nuclear fractions. PKC-gamma expression in the membrane and nuclear fractions was decreased following 1 h of PMA stimulation. The expression of PKC-zeta in the membrane and nuclear fractions was transiently increased (2-3 fold) between 3-6 h after PMA stimulation. The expression of PKC epsilon and delta was also affected by PMA treatment. While PKC epsilon, in the membrane fraction, was down-regulated by PMA treatment (3 h), the expression of PKC delta was induced by PMA. Confocal microscopy of the translocation of PKC isoforms during PMA-induced differentiation, confirmed the results obtained by Western blot analysis. Our results indicate that both Ca2+-dependent (PKC-alpha and PKC-gamma) and Ca2+-independent (PKC-epsilon, delta and PKC-zeta) isozymes are expressed in AGF cells and their pattern of expression differ in response to short and prolonged stimulation with phorbol ester. The demonstrated heterogeneity of PKC isozymes in AGF cells, suggests that each PKC isoform may provide a unique contribution to signal transduction pathways and growth control.

Targeted therapy for osteosarcoma using 17AAG and rapamycin: Identification of new targets using Gene Microarray profiling and MiRNA

10027

Background: Sarcomas constitute a group of diverse diseases with many subtypes and varying prognoses. Hence, new approaches for therapy involving targeting of specific survival pathways are needed. Methods: We used 17-AAG to block HSP90 and rapamycin (Ra) to block mTOR, in 2 osteosarcoma cell lines, HOS and KHOS/NP. Cells were treated for 24 and 48 hours with 200 nM of 17- AAG or 5 micromolar of rapamycin. Gene profiling (GP) was performed using h-U133 2 Plus Array (Affymetrix). Results were pre-filtered using the GCOS pair-wise comparisons. ANOVA was filtered for >2-fold change between two conditions. We compared control HOS or KHOS vs. 24 H or 48 H treatment with Ra, or 17AAG. Gene identity, ontology and z-scores were derived. For micro RNAs (miRs), we used a miRNA chip (LC Sciences) and data were normalized, adjusted and clustered using t-test (p<0.01). Results and Conclusions: 17-AAG is a good inducer of apoptosis in HOS and KHOS cells (IC50 of ∼50nM) and blocked cells at mitosis. Ra is a weak inducer of apoptosis (IC20 at 5 micromolar) and blocked cells at G1. GP of 17AAG treated HOS/KHOS cells revealed >1,000 and 1,600 gene changes at 24 H and 48 H, respectively, with ∼700 genes affected at 24 and 48H. Ra affected ∼400 and ∼350 genes at 24 and 48H, respectively, with 20 genes affected at 24 and 48H. Of the genes upregulated by 17AAG, >450 were in cell and protein metabolism; >50 genes were in chromatin modifications and >40 in regulation of cell cycle. With 17AAG, changes were found in histones and deacetylases; cytoskeleton proteins; extracellular matrix proteins and MMPs; HSPs; MAP kinase, mTOR, IGF and VEGF pathways; cell cycle and apoptosis. Many targets were validated by by immunoblotting. MiRs were profiled following 24H treatment with 17AAG or Ra. 17AAG upregulated miR122a;145;143 and 663 (4–16 fold) and miR 542–5P was decreased (∼12 fold). Ra upregulated miR 498;145;143;452;663; 602 and miR224 (4–32 fold) and downregulated (4–32 fold) miR1;542–5P and miR335. Taken together, miR changes affect the expression of transcripts related to angiogenesis; cell cycle; cell signaling and apoptosis and are common to the changes observed by GP. In summary, new therapeutic targets were identified by the combination of GP and miRNA following 17AAG or rapamycin.

No significant financial relationships to disclose.

Homing and mobilization of hematopoietic stem cells and hematopoietic cancer cells are mirror image processes, utilizing similar signaling pathways and occurring concurrently: circulating cancer cells constitute an ideal target for concurrent treatment with chemotherapy and antilineage-specific antibodies

Adhesion molecules and stromal cell-derived factor-1 (SDF-1)/CXCR4 signaling play key role in homing and mobilization of hematopoietic progenitor (HPC) and hematopoietic cancer clonogenic cells (HCC). High expression of VLA-4 is required for homing of HPC and HCC, whereas downregulation of these molecules is required for successful mobilization of HPC and HCC. Upregulation and activation of the SDF-1/CXCR4 signaling is required for homing of HPC and HCC, whereas disruption of the SDF-1 signaling is required for mobilization of HPC and HCC. Hence, mobilizations of HPC and HCC occur concurrently. It is proposed that drug resistance evolves as a result of repeated cycles of chemotherapy. Following each cycle of chemotherapy, HCC lose adhesion molecules and SDF-1 signaling. Surviving cells, released from tumor sites, circulate until re-expression of adhesion molecules and CXCR4 occurs, then homing to stroma of distal tissues occurs. Cytokines secreted by cells in the new microenvironment induce proliferation and drug resistance of HCC. This process is amplified in each cycle of chemotherapy resulting in disease progression. A novel model for treatment is proposed in which circulating HCC are the target for clinical intervention, and concurrent treatment with chemotherapy and antilineage-specific antibodies will result in abrogation of the 'vicious cycle' of conventional anticancer therapy.

Antisense inhibition of macrophage inflammatory protein 1-alpha blocks bone destruction in a model of myeloma bone disease

We recently identified macrophage inflammatory protein 1-alpha (MIP-1alpha) as a factor produced by multiple myeloma (MM) cells that may be responsible for the bone destruction in MM (1). To investigate the role of MIP-1alpha in MM bone disease in vivo, the human MM-derived cell line ARH was stably transfected with an antisense construct to MIP-1alpha (AS-ARH) and tested for its capacity to induce MM bone disease in SCID mice. Human MIP-1alpha levels in marrow plasma from AS-ARH mice were markedly decreased compared with controls treated with ARH cells transfected with empty vector (EV-ARH). Mice treated with AS-ARH cells lived longer than controls and, unlike the controls, they showed no radiologically identifiable lytic lesions. Histomorphometric analysis demonstrated that osteoclasts (OCLs) per square millimeter of bone and OCLs per millimeter of bone surface of AS-ARH mice were significantly less than in EV-ARH mice, and the percentage of tumors per total bone area was also significantly decreased. AS-ARH cells demonstrated decreased adherence to marrow stromal cells, due to reduced expression of the alpha(5)beta(1) integrin and diminished homing capacity and survival. These data support an important role for MIP-1alpha in cell homing, survival, and bone destruction in MM.

Additive effect of Apo2L/TRAIL and Adeno-p53 in the induction of apoptosis in myeloma cell lines

OBJECTIVE

We have previously shown that Adenovirus-p53 (Ad-p53) is a potent inducer of apoptosis in myeloma cells expressing nonfunctional p53 and low levels of bcl-2 and that Apo2L/TRAIL is a potent inducer of apoptosis, independent of bcl-2. A study was designed to test the synergy between Ad-p53 and Apo2L/TRAIL in the induction of apoptosis in relation to the expression of DR4/DR5 and DcR1, in cells undergoing Ad-p53-induced apoptosis.

METHODS

Replication deficient Ad-p53 and human recombinant Apo2L/TRAIL were used. Myeloma cells with mutated/w.t. p53 and varying expression of bcl-2 were used to test the effect of Ad-p53, Apo2L/TRAIL, or both, on apoptosis, measured by annexin V.

RESULTS

Treatment with Ad-p53 resulted in a dose-dependent apoptosis concomitant with a dose-dependent increase in the expression of DR4/DR5 and a decrease in the expression of DcR1, in Ad-p53-sensitive cell lines. In these cells, addition of Apo2L/TRAIL to cells treated with Ad-p53 resulted in a dose-dependent increase in apoptosis. Myeloma cells resistant to Ad-p53 had high levels of DR4/DR5 and high levels of DcR1 and treatment with Ad-p53 did not reduce the expression of DcR1. Also, addition of Apo2L/TRAIL to Ad-p53 did not affect the level of apoptosis beyond the level of apoptosis observed with Apo2L/TRAIL alone.

CONCLUSIONS

1) Cotreatment with Ad-p53 and Apo2L/TRAIL resulted in additive apoptosis in myeloma cells expressing nonfunctional p53 and low levels of bcl-2. 2) Resistance to Ad-p53 or to the combination of Ad-p53 and Apo2L/TRAIL was not due to the lack of adenovirus receptor (CAR) or low expression of DR4/DR5 but rather due to the relatively high expression of DcR1 receptor.

Myeloablation and autologous peripheral blood stem cell rescue results in hematologic and clinical responses in patients with myeloid metaplasia with myelofibrosis

Current therapeutic options for myeloid metaplasia with myelofibrosis (MMM) are limited. A pilot study was conducted of autologous peripheral blood stem cell (PBSC) collection in 27, followed by transplantation in 21 patients with MMM. The median age was 59 (range 45-75) years. PBSCs were mobilized at steady state (n = 2), after granulocyte colony-stimulating factor (G-CSF) alone (n = 17), or after anthracycline-cytarabine induction plus G-CSF (n = 8). A median of 11.6 x 10(6) (range 0 to 410 x 10(6)) CD34(+) cells per kilogram were collected. Twenty-one patients then underwent myeloablation with oral busulfan (16 mg/kg) and PBSC transplantation. The median times to neutrophil and platelet recovery after transplantation were 21 (range 10-96) and 21 (range, 13 to > or = 246) days, respectively. Five patients received back-up PBSC infusion because of delayed neutrophil or platelet recovery. The median follow-up is 390 (range 70-1623) days after transplantation, and the 2-year actuarial survival is 61%. After transplantion, 6 patients died: 3 of nonrelapse causes (1 within 100 days of PBSC infusion) and 3 of disease progression. Erythroid response (hemoglobin > or = 100 g/L [10 gm/dL] without transfusion for > or = 8 weeks) occurred in 10 of 17 anemic patients. Four of 8 patients with a platelet count less than 100 x 10(9)/L (100 000/microL) responded with a durable platelet count more than 100 x 10(9)/L (100 000/microL). Symptomatic splenomegaly improved in 7 of 10 patients. It is concluded that (1) PBSC collection was feasible and stable engraftment occurred after transplantation in most patients with MMM, (2) myeloablation with busulfan was associated with acceptable toxicity, (3) a significant proportion of patients derived clinical benefit after treatment, and (4) further investigation of this novel approach is warranted. (Blood. 2001;98:586-593)

Expression of adhesion molecules on CD34(+) cells in peripheral blood of non-hodgkin's lymphoma patients mobilized with different growth factors

Adhesion molecules on CD34(+) cells were implicated in the process of peripheral blood stem cell (PBSC) mobilization and homing. We studied the mobilization of CD34(+)Thy1(+) cells, CD34(+) very late-acting antigen (VLA)4(+) cells, and CD34(+)L-selectin(+) cells in non-Hodgkin's lymphoma patients mobilized with cyclophosphamide plus G-CSF, GM-CSF, or GM-CSF followed by G-CSF. The mean percentage of CD34(+) cells in the bone marrow (BM) expressing Thy1 was 23.6% +/- 11% and 17.8% +/- 8% in the PB before mobilization, and was markedly decreased to 4.5% +/- 3.3% in the apheresis collections. Similarly, the mean percentage of CD34(+) cells expressing L-selectin was 35.8% +/- 4.3% in the BM, 21.6% +/- 4.1% in the PB before mobilization and was markedly decreased to 9.1% +/- 2.5% in the apheresis collections. Patients in the three arms of the study had a similar pattern of CD34(+)Thy1(+) and CD34(+)L-selectin(+) cell mobilization. Also, a similar pattern of coexpression of CD34(+)Thy1(+) and CD34(+)L-selectin(+) cells was observed when the patients were regrouped as "good mobilizers" (> or =2 x 10(6) CD34(+)CD45(dim) cells/kg, in four collections) and "poor mobilizers" (<0.4 x 10(6) CD34(+)CD45(dim) cells/kg, in two collections). The mean percentage of CD34(+) cells expressing VLA-4 in the BM and PB was relatively high (73.4% +/- 12% and 65.4% +/- 6.6%, respectively) and dropped considerably in the PBSC collections to 43.5% +/- 7.1% with a similar pattern observed for patients in arms A, B, and C. However, when the patients were regrouped as "good mobilizers" and "poor mobilizers," a higher percentage of CD34(+) cells expressing VLA-4 was observed in the PBSC of the pooled "good mobilizers" (50.5% +/- 9% versus 36.3% +/- 6.4%; p = 0.01). We conclude that release of CD34(+) cells to the PB involves a general downregulation of Thy1, L-selectin and VLA-4 on CD34(+) cells, irrespective of the growth factor used for mobilization. However, good mobilizers had a relatively higher percentage of CD34(+) cells expressing the VLA-4 antigen.

Plasma levels of SDF-1 and expression of SDF-1 receptor on CD34+ cells in mobilized peripheral blood of non-Hodgkin's lymphoma patients

CXCR4 is the receptor for the chemokine stromal derived factor-1 (SDF-1), is expressed on CD34+ cells, and has been implicated in the process of CD34+ cell migration and homing. We studied the mobilization of CD34/CXCR4 cells and the plasma levels of SDF-1 and flt3-ligand (flt3-L) in 36 non-Hodgkin's lymphoma patients receiving cyclophosphamide (Cy) plus G-CSF (arm A), Cy plus GM-CSF (arm B), or Cy plus GM-CSF followed by G-CSF (arm C) for peripheral blood stem cell (PBSC) mobilization and autotransplantation. We observed lower plasma levels of SDF-1 in PBSCs compared to premobilization bone marrow samples. The mean plasma SDF-1 levels were similar in PBSC collections in the three arms of the study. In contrast, SDF-1 levels in the apheresis collections of the "good mobilizers" (patients who collected a minimum of 2 x 10(6) CD34+ cells/kg in one to four PBSC collections) were significantly lower than the apheresis collections of the "poor mobilizers" (> or = 0.4 x 10(6) CD34+ cells/kg in the first two PBSC collections; 288 +/- 82 pg/ml versus 583 +/- 217 pg/ml; p = 0.0009). The mean percentage of CD34+ cells expressing CXCR4 in the apheresis collections was decreased in the PBSC collections compared with premobilization values from 28% to 19.4%. Furthermore, the percentage of CD34+ cells expressing CXCR4 in the good mobilizers was significantly lower compared with the poor mobilizers (14.7 +/- 2.1% versus 33.6 +/- 2.1%; p = 0.002). The good mobilizers had also significantly lower levels of flt3-L compared with the poor mobilizers (34 +/- 4 pg/ml versus 106 +/- 11 pg/ml; p = 0.006), Finally, the levels of flt3-L strongly correlated with SDF-1 levels (r = 0.8; p < 0.0001). We conclude: A) low plasma levels of SDF-1 and low expression of CXCR4 characterize patients with good mobilization outcome, and B) the levels of SDF-1 correlate with flt3-L, suggesting an association of these cytokines in mobilization of CD34+ cells.

Recent Developments in the Regulation of Peripheral Blood Stem Cell Mobilization and Engraftment by Cytokines, Chemokines, and Adhesion Molecules

Peripheral blood stem cells (PBSC) have become the preferred source of stem cells for autologous transplantation because of the technical advantage and the shorter time to engraftment. Administration of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) results in mobilization of PBSCs into the peripheral blood. G-CSF and GM-CSF differ somewhat in the number and composition of CD34(+) cells and effector cells mobilized to the peripheral blood; however, the molecular mechanism underlying the release and engraftment of CD34(+) cells by these growth factors is poorly understood. This review provides a recent update on the involvement of hematopoietic growth factors, chemokines, adhesion molecules, and chemokine receptors in the regulation of stem cell release and engraftment. The involvement of very late antigen-4 (VLA-4), VLA-5, leukocyte function associated-1 molecule (LFA-1), and L-selectin and their receptors CXCR4 and its ligand SDF-1 will be discussed, and cross talk between these factors will also be reviewed in the context of stem cell release and engraftment. Finally, PBSC mobilization by chemokines will be reviewed in relation to hematopoietic growth factors.

A new molecular role for iron in regulation of cell cycling and differentiation of HL-60 human leukemia cells: iron is required for transcription of p21(WAF1/CIP1) in cells induced by phorbol myristate acetate

To investigate the role of iron in hematopoiesis, we studied effects of iron deprivation on PMA-induced monocyte/macrophage differentiation in HL-60 cells. Iron deprivation induced by desferrioxamine (DF) blocked PMA-induced differentiation and induced S-phase arrest and apoptosis in up to 60% of cells. Apoptosis was not related to a decrease of bcl-2 or to c-myc overexpression. In the presence of DF, PMA-induced upregulation of the cyclin dependent kinase inhibitor (CDKI), p21(WAF1/CIP1), was blocked and its expression could be restored in the presence of DF by supplementation with ferric citrate. Furthermore, ferrioxamine (iron saturated DF) did not block induction of p21(WAF1/CIP1) indicating that the changes were not due to a nonspecific toxic effect of DF. Similarly, hydroxyurea, an inhibitor of ribonucleotide reductase, did not block p21 expression. p21(WAF1/CIP1) antisense oligonucleotides caused cell cycle alterations similar to DF and p21 overexpression overcame effects of iron deprivation on both cell cycling and differentiation. Therefore, p21 is a key target for the effects of iron deprivation on HL-60 cell cycling and differentiation. Nuclear run-on transcription assays and p21 mRNA half-life studies indicated that iron was required to support transcriptional activation of p21(WAF1/CIP1) after a PMA stimulus. By contrast, iron deprivation did not inhibit expression of a second CDKI, p27(KIP1). These data demonstrate a new role for iron during monocyte/macrophage differentiation. A key role of iron is to allow induction of p21(WAF1/CIP1) in response to a differentiation stimulus subsequently blocking cells at the G(1)/S cell cycle interface and preventing premature apoptosis. This effect of iron is independent of its requirement in supporting the activity of the enzyme, ribonucleotide reductase. Because of the central role of p21(WAF1/CIP1) as regulator of the G(1)/S cell cycle checkpoint this requirement for iron to support p21 expression represents an important mechanism by which iron may modulate hematopoietic cell growth and differentiation. Published 2001 Wiley-Liss, Inc.

Immunologic profiles of effector cells and peripheral blood stem cells mobilized with different hematopoietic growth factors

BACKGROUND

Peripheral blood stem cells (PBSC) have become the preferred source of stem cells for autologous transplantation because of the technical advantage and the shorter time to engraftment. Mobilization of CD34(+) cells into the peripheral blood can be achieved by the administration of G-CSF or GM-CSF, or both, alone or in combination with chemotherapy. G-CSF and GM-CSF differ somewhat in the number and composition of CD34(+) cells and effector cells mobilized to the peripheral blood. However, the molecular mechanism underlying the release and engraftment of CD34(+) cells is poorly understood.

PURPOSE

The purpose of this review is to give a recent update on the type and immunological properties of effector cells and CD34(+) cells mobilized by the different growth factors with emphasis on A) mobilization of T cells, natural killer cells, and dendritic cells; B) coexpression of adhesion molecules such as VLA-4 and L-selectin in mobilized PBSC collection, and C) coexpression of CXCR4-the receptor for the stromal-derived differentiation factor 1-with latest information shedding light on the molecular mechanism underlying the release and subsequent engraftment of CD34(+) cells.

CONCLUSIONS

A) The reported suppression of T cell and NK cell functions in PBSC apheresis collections in patients primed with G-CSF or GM-CSF is controversial and may merely reflect low effector cell activity before mobilization. B) A decrease in the expression of adhesion molecules such as VLA-4 and L-selectin is a necessary requirement for the release of CD34(+) cells to the peripheral blood. C) A decrease in the expression of CXCR4 is a necessary requirement for the release of CD34(+) cells to the peripheral blood and correlates with mobilization success.

Enhanced TRAIL sensitivity by p53 overexpression in human cancer but not normal cell lines

The cytotoxic ligand TRAIL is a promising anti-cancer agent that is entering into clinical trials. We previously identified a major subgroup of TRAIL resistant cancer cell lines with absent, or reduced DR4 expression containing a K441R polymorphism or harboring elevated levels of the caspase activation inhibitor FLIP. In the present study, we explored the use of a gene therapeutic approach utilizing p53, delivered by an adenovirus-p53 (Ad-p53) vector, which directly controls expression of the TRAIL receptor KILLER/DR5 in a panel of 8 cell lines including normal and TRAIL sensitive or resistant cancers. The functional status of the delivered p53 was monitored by detection of induced p21WAF1 expression by immunocytochemistry. In normal cells, which are TRAIL resistant, TRAIL did not reduce cell viability over and above the effect of Ad-p53 alone. All cancer cell lines were sensitive to Ad-p53 and up-regulated expression of the TRAIL receptor KILLER/DR5. TRAIL-resistant cancer cells became more sensitive to TRAIL at low Ad-p53 multiplicities of infection but TRAIL resistance was not completely overcome in one TRAIL-resistant cell line probably because of a high level of expression of FLIP. The results reveal that Ad-p53 induces the TRAIL receptor KILLER/DR5 and, like radiation or chemotherapy may effectively reverse TRAIL resistance.

Mobilization of dendritic cells and NK cells in non-Hodgkin's lymphoma patients mobilized with different growth factors

Conflicting results have been reported regarding the effect of various growth factors on the mobilization of natural killer (NK) cells and dendritic cells in patients undergoing stem cell mobilization for autotransplantation. We compared the extent of mobilization of NK cells and dendritic cells in non-Hodgkin's (NHL) patients undergoing mobilization with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage (GM)-CSF, or GM-CSF followed by G-CSF. Overall, 35 patients were studied. NK cells and dendritic were quantitated by flow cytometry. NK cells were defined as the sum of CD56(+) cells and CD56/CD16(+) cells. Dendritic cells were defined as the sum of CD80(+) and CD80(+)/CD14(+) cells. NK activity was determined by by microcytotoxicity assay. NK activity correlated well with the total amount of CD56(+) cells mobilized to the peripheral blood. Patients in the three arms of the study mobilized similar amounts of NK cells and NK activity, and patients who lacked NK activity in the peripheral blood, before mobilization, lacked NK activity in their apheresis collections. In contrast to NK cell mobilization, mobilization of dendritic cells/kg was three- to five-fold higher in patients mobilized with GM-CSF-containing regimens compared to patients mobilized with G-CSF alone. We conclude that GM-CSF-containing mobilization regimens are superior for dendritic cell mobilization but similar in the mobilization of NK cells. Therefore, we recommend using GM-CSF-containing regimens for patients undergoing ex vivo or in vivo manipulation of dendritic cells.

Differential mobilization of CD34+ cells and lymphoma cells in non-Hodgkin's lymphoma patients mobilized with different growth factors

Co-mobilization of CD34(+) cells and tumor has been documented in patients with different types of cancer undergoing peripheral blood stem cell transplantation (PBSCT). Conflicting reports were published regarding the role of various growth factors in tumor cells mobilization, hence we studied the extent of CD34(+) cells and lymphoma cell mobilization in 35 non-Hodgkin's (NHL) patients primed by cyclophosphamide (Cy) in combination with granulocyte colony-stimulating factor (GCSF) (A, 13 patients), granulocyte-macrophage (GM)-CSF (B, 10 patients), or GM-CSF followed by G-CSF (C, 12 patients). CD34(+) cells were quantitated by flow cytometry and lymphoma cells by the TaqMan Real Time PCR for bcl-2 gene rearrangement. Successful collection in 4 days of > or = 2 x 10(6) CD34(+) cells/kg needed for prompt engraftment was obtained in 76%, 60%, and 58% of patients in arms A, B, and C, respectively. Lymphoma cell mobilization was detected in 35% patients tested, 78% of which had follicular lymphoma. Lymphoma cell mobilization was similar in the three arms of the study, however, presence of lymphoma cells was prevalent in patients who failed to mobilize the amount of 0.4 x 10(6) CD34(+) cells/kg in 2 days ("poor mobilizers") and reached 42%, compared to 17% in the "successful mobilizers" group of patients. Lymphoma cell contamination in PBSCs was detected proportionately in the peripheral blood and in the bone marrow. We conclude that bcl-2 gene rearrangement is prevalent in patients with follicular histology, and, in these patients, an inverse relationship was observed between mobilization of CD34(+) cells and lymphoma cells. Our results explain the high relative risk (1.98) for mobilization in patients with follicular histology.

Adenovirus-mediated delivery of p53 results in substantial apoptosis to myeloma cells and is not cytotoxic to flow-sorted CD34(+) hematopoietic progenitor cells and normal lymphocytes

Multiple myeloma (MM) is an incurable disease; therefore, there is a need for new modalities of treatment for this disease. We designed a study to test the sensitivity of MM cell lines, freshly isolated myeloma cells, and CD34(+) hematopoietic progenitor cells to adenovirus-mediated delivery of wild-type p53 (Ad-p53). Replication-deficient Ad-p53, previously used in phase I-II clinical trial for treatment of patients with solid tumors, was used in this study. Myeloma cells from seven MM cell lines with mutated or w.t. p53 and varying expression of bcl-2 were used. Fresh myeloma cells (CD38(bright)CD45(-)) and fresh CD34(+) hematopoietic stem cells and CD34(-) cells were purified by flow sorting of apheresis collections of MM patients undergoing high-dose chemotherapy and stem cell rescue. The effect of Ad-p53 on colony-forming unit granulocyte-macrophage (CFU-GM) and burst-forming unit erythroid (BFU-E) colony formation in methylcellulose was tested on purified CD34(+) and CD34(-) cells to evaluate bone marrow toxicity. Myeloma cells from cell lines, or freshly isolated myeloma cells, were sensitive to Ad-p53 only if they had mutated p53 and had low expression of bcl-2. CD34(+) cells were resistant to Ad-p53-mediated apoptosis, and CFU-GM and BFU-E colony formation was not affected by treatment with Ad-p53.Ad-p53 is a potent inducer of apoptosis in MM cell lines and in freshly isolated myeloma cells expressing low levels of bcl-2. Ad-p53 is not overtly cytotoxic to normal hematopoietic stem cells or normal lymphocytes; therefore, it could be considered for a phase I clinical trial of MM patients with mutated p53.

Peripheral blood stem cell mobilization with cyclophosphamide in combination with G-CSF, GM-CSF, or sequential GM-CSF/G-CSF in non-Hodgkin's lymphoma patients: a randomized prospective study

We designed a randomized, prospective three-arm mobilization study to determine the kinetics of peripheral blood stem cell (PBSC) mobilization in 60 non-Hodgkin's lymphoma (NHL) patients primed with cyclophosphamide (CTX) in combination with granulocyte colony-stimulating factor (G-CSF) (arm A), granulocyte-macrophage (GM)-CSF (arm B) or GM-CSF/G-CSF (arm C). We also compared mobilization and transplant-related toxicities, pre- and post-transplant support and the probability of survival among the three arms. To date, 35 patients have been enrolled in the study; 13 patients have been enrolled in arm A, 10 patients in arm B, and 13 patients in arm C. Successful collection of the target of > or = 2 X 10(6) CD34+ cells/kg in one to four apheresis collections was 10/13, 6/10, and 7/12 in arms A, B, and C, respectively. The differences between arms were not statistically significant. The median time to achieve the target CD34+ cells in patients who successfully mobilized the target CD34+ cells was 3 days, 2 days, and 1 day, in patients in arms A, B, and C, respectively. The time for neutrophil engraftment was 11, 10, and 10 days in arms A, B, and C, respectively. The time for platelet engraftment was 11 days for patients in all arms of the study. Most importantly, no significant differences were observed among the three arms in the duration of neutropenic fever, the extent of mucositis, diarrhea, and nausea/vomiting, or in the number of units of platelets or red cells transfused after transplantation. Risk factors associated with poor mobilization were > or = 3 regimens of chemotherapy prior to mobilization, older age, and disease histology (follicular versus diffuse). Therefore, we conclude that the type of growth factor used for mobilization did not play a major role in the outcome of mobilization and recommend mobilizing NHL patients before they receive multiple regimens of chemotherapy.

High steady-state plasma levels of flt3-ligand in the peripheral blood is a good predictor for poor mobilization of CD34+ PBSC in patients undergoing high-dose chemotherapy and stem cell rescue

flt3-ligand (flt3-L) is a very effective mobilizer of hematopoietic stem cells (HSC) and is capable of inducing multilineage hematopoietic cell differentiation both in vivo and in vitro. We measured, by ELISA, the plasma peripheral blood flt3-L concentrations in 28 non-Hodgkin's lymphoma (NHL) patients before and after mobilization with three different mobilization regimens, including priming with cyclophosphamide (CY) plus G-CSF, CY plus GM-CSF, and CY plus GM-CSF (8 days) followed by G-CSF. We also determined the levels of flt3-L in the peripheral blood during four apheresis collections and 6 months after transplantation. The steady-state level of flt3-L in NHL patients (n = 18) who mobilized > or =2 x 10(6) CD34+ cells/kg in four apheresis collections was 34 +/- 4 pg/ml and was similar to the levels observed in 10 normal controls (27 +/- 7, p = 0.1) regardless of the mobilization protocol used. In contrast, patients who failed to mobilize a total of >0.4 x 10(6) CD34+ cells/kg in two consecutive apheresis collections (n = 10) had flt3-L levels of 106 +/- 11 pg/ml, significantly higher (p = 0.006) than that of the good mobilizers group, regardless of the mobilization protocol used. Similar results were observed in 29 multiple myeloma (MM) patients. A mean of 23.8 +/- 7.9 pg/ml and 450 +/- 85 pg/ml flt3-L was obtained in the good mobilizers (n = 24) and the nonmobilizers (n = 5) groups of patients, respectively. Statistical analysis revealed a significant difference (p = 0.0006) between the two groups of MM patients, but no correlation was observed between the levels of flt3-L and CD34+ cell/microl, in mobilized peripheral blood. Our results also suggest that measurement of plasma levels of flt3-L before mobilization can be clinically useful to predict for patients with poor mobilization outcome.

Apoptosis-induced by TRAIL AND TNF-alpha in human multiple myeloma cells is not blocked by BCL-2

TRAIL, the ligand for the newly discovered DR-4 and DR-5 receptor is a member of the tumour necrosis factor (TNF) family of death signal tranduction proteins with a mechanism of cell death, similar to the Fas and Fas ligand (Fas-L) system. Here, we provide first time evidence that TRAIL and TNF-alpha are potent inducers of apoptosis in multiple myeloma (MM) cell lines and freshly isolated myeloma cells. TRAIL effectively induced extensive apoptosis in 8226 and ARP-1 MM cells in a time- and dose-dependent manner reaching 80% within 48 h of treatment with a dose of 160 ng/ml. Bcl-2 transfected 8226 and ARP-1 cells were equally sensitive to apoptosis by TRAIL. Apoptosis with TNFalpha, reached >60% within 48 h of treatment with a dose of 160 ng/ml. In addition to MM cell lines, freshly isolated, flow-sorted myeloma cells from 8 different MM patients expressing variable levels of bcl-2 were equally sensitive to both TRAIL and TNF-alpha. We have previously shown that anti-Fas-induced apoptosis is not blocked by endogenous or ectopic bcl-2 in MM cell lines. Here we extend our observation with Fas to include TNF-alpha and TRAIL to the apoptotic signals that are not be blocked by bcl-2, in MM cells.

TRAIL is a potent inducer of apoptosis in myeloma cells derived from multiple myeloma patients and is not cytotoxic to hematopoietic stem cells

TRAIL, the ligand for the newly discovered DR-4 and DR-5 receptor, is a member of the TNF family of death signal transduction proteins with a mechanism of cell death similar to that of Fas and Fas ligand (Fas-L) system. We provide first time evidence that TRAIL is a potent inducer of apoptosis in multiple myeloma (MM) cell lines. TRAIL effectively induced extensive apoptosis in 8226 and ARP-1 MM cells in a time- and dose-dependent manner. Apoptosis with TRAIL reached about 80% within 48 h of treatment with a dose of 160 ng/ml. Furthermore, we provide first time evidence that similar to Fas, TRAIL-induced apoptosis is not blocked by bcl-2 in MM cell lines. Most importantly, TRAIL induced substantial apoptosis in freshly isolated, flow-sorted myeloma cells obtained from different MM patients expressing variable levels of bcl-2. Finally, we demonstrate for the first time that TRAIL is not cytotoxic to purified CD34+/CD45dim hematopoietic stem cells and does not inhibit CFU-GM or BFU-E colony formation in methylcellulose.

Annexin II increases osteoclast formation by stimulating the proliferation of osteoclast precursors in human marrow cultures

Annexin II (AXII), a calcium-dependent phospholipid-binding protein, has been recently found to be an osteoclast (OCL) stimulatory factor that is also secreted by OCLs. In vitro studies showed that AXII induced OCL formation and bone resorption. However, the mechanism of action by which AXII acts as a soluble extracellular protein to induce OCL formation is unknown. In this paper, we demonstrate that AXII gene expression is upregulated by 1,25-dihydroxyvitamin D3 [1, 25-(OH)2D3] and that addition of AXII significantly increased OCL-like multinucleated cell formation. Time-course studies suggested that AXII acted on the proliferative stage of OCL precursors and that AXII increased thymidine incorporation in OCL precursors. Moreover, AXII enhanced the growth of CFU-GM, the earliest identifiable OCL precursor, when bone marrow cultures were treated with low concentrations of GM-CSF. This capacity of AXII to induce OCL precursor proliferation was due to induction of GM-CSF expression, because the addition of neutralizing antibodies to GM-CSF blocked the stimulatory effect of AXII on OCL formation. RT-PCR analysis using RNA from highly purified subpopulations of marrow cells demonstrated that T cells, especially CD4(+) T cells, produced GM-CSF in response to AXII. Furthermore, FACS(R) analysis of T-cell subpopulations treated with fluorescein-labeled AXII suggested that the CD4(+), but not CD8(+), subpopulation of T cells express an AXII receptor. Taken together, these data suggest that AXII stimulates OCL formation by activating T cells through a putative receptor to secrete GM-CSF. GM-CSF then expands the OCL precursor pool to enhance OCL formation.

Successful PBSC mobilization with high-dose G-CSF for patients failing a first round of mobilization

PBSC are the preferred source of stem cells for autologous transplantation. However, regardless of the mobilization procedure used, 10%-20% of patients fail to collect an adequate number to ensure prompt engraftment. There is as yet no standard mobilization procedure for patients who fail a first mobilization attempt. Here, we describe a highly efficient strategy to obtain an adequate number of stem cells for patients who failed a first mobilization attempt. Seventy-four patients with various hematologic malignancies underwent initial mobilization with various regimens including hematopoietic growth factors with or without chemotherapy. In 72% of patients, > or =2 x 10(6) CD34+ stem cells/kg were collected in the initial mobilization attempt, and patients engrafted in a median of 10 days for neutrophils and 12 days for platelets. Eighteen patients failed to mobilize adequate numbers of stem cells, defined as the inability to collect 0.2 x 10(6) CD34+ stem cells/kg/day in the first 2-3 days. These patients had their apheresis halted. Patients were immediately given G-CSF (32 microg/kg/day) for 4 days as a second attempt at mobilization. Eighty-eight percent of these patients achieved the target of > or =2 x 10(6) CD34+ cells/kg, with a median duration of apheresis of 5 days (including the first and second mobilizations). The mean CD34+ cells/kg/day increased after administration of high-dose G-CSF from 0.16 after the first mobilization attempt to 0.61 (p = 0.0002) after the second mobilization. All patients engrafted in a median of 11 and 13 days for neutrophils and platelets, respectively. We conclude that patients whose apheresis yield is <0.4 x 10(6) CD34+ cells/kg after the first two apheresis collections can be successfully mobilized if high-dose G-CSF is administered immediately and continued until achieving > or =2 x 10(6) CD34+ stem cells/kg.

Bcl-2 overexpression is associated with resistance to paclitaxel, but not gemcitabine, in multiple myeloma cells

Multiple myeloma (MM) is an incurable disease despite an initial response-rate of >60% with conventional or high-dose chemotherapy using glucocorticosteroids (i.e. dexamethasone), or alkylating agents (i.e. melphalan). Although these agents are capable of inducing complete remission (CR) in >50% of MM patients, resistance develops rapidly, in >90% of patients, within 2 years of treatment. Therefore, there is a need for new drugs for the treatment of relapsing and refractory MM patients. Gemcitabine (GEM) is a pyrimidine analog that blocks DNA synthesis, whereas, paclitaxel (TAX) is a mitotic spindle poison that promotes microtubular aggregation. Since it appears that these two drugs have different cellular targets, we examined the effect of each drug individually for several parameters and for possible synergy. We studied the cytotoxic effect of TAX and GEM on MM cells expressing varying levels of the antiapoptotic protein bcl-2, which is overexpressed in the majority of myeloma cell from MM patients. We found that both drugs are cytotoxic by inducing apoptosis, however, the extent of apoptosis with TAX, but not with GEM was dependent on the levels of bcl-2 expression. We further investigated the effect of TAX and GEM on the cell cycle distribution and on the levels of bcl-2. The results indicate that the two drugs have different modes of action with respect to each parameter tested. TAX induced arrest of the cells in the G2/M phase of the cell cycle, regardless of bcl-2 levels, however, apoptosis was induced in mitotic cells expressing relatively low levels of bcl-2. In contrast, GEM caused apoptosis of cells in the S-phase, regardless of level of bcl-2 expression. A major difference between TAX and GEM was in their effects on the levels of bcl-2. Whereas, TAX induced an early downregulation of bcl-2 (only in the cells with relatively low levels of bcl-2), treatment with GEM did not affect bcl-2 levels. The effects of TAX on both the cell cycle and bcl-2 were detected very early (4-8 h) and preceded the onset of apoptosis. GEM and TAX act synergistically, at low doses (IC50 of 0.5 microM for GEM and 0.025 microM for TAX), to effectively kill bcl-2 overexpressing cells that are resistant to higher doses (0.25 microM) of TAX alone. Therefore, we have initiated a phase II clinical trial of TAX and GEM for MM patients refractory to current therapy.

Bcl-2 overexpression is associated with resistance to dexamethasone, but not melphalan, in multiple myeloma cells

Multiple myeloma (MM) is an incurable disease despite an initial response-rate of >60% with conventional or high-dose chemotherapy. Glucocorticosteroids such as dexamethasone (DEX) and alkylating agents such as melphalan (MEL) are capable of inducing complete responses (CR) in >50% of MM patients, however, resistance to these drugs develop rapidly, in >90% of patients, within 2 years of treatment. The exact mechanism of resistance to these drugs is not known. We investigated the mechanism of resistance to DEX and MEL. In particular, we investigated the role of bcl-2 in development of resistance to these two drugs. We tested the role of bcl-2 by transfecting 2 low bcl-2-expressing myeloma cell lines, ARP-1 and 8226, with a bcl-2 expression vector and compared the effects of DEX and MEL on apoptosis, cell cycle distribution and the levels of proapoptotic (bax) and antiapoptotic (bcl-2, bclx) proteins. The results indicate that the two drugs act by a different mechanism with respect to all the parameters tested. While DEX-induced apoptosis was dependent on the level of bcl-2 expression, MEL-induced apoptosis was independent of bcl-2 levels. Treatment with DEX of the low bcl-2-expressing cells (DEX-sensitive) resulted in a rapid apoptosis from all phases of the cell cycle. In contrast, treatment with MEL blocked the cells in late-S/G2 phase of the cell cycle and caused substantial apoptosis, regardless of bcl-2 expression. Major differences between DEX and MEL were also observed with respect to their effects on the levels of bcl-2 and p53. Whereas DEX induced an early (day 1) downregulation of bcl-2 (only in the cells with low bcl-2), treatment with MEL did not affect bcl-2 levels. The levels of bclx and bax remained unchanged following treatment with either MEL or DEX. These results, taken together, suggest that the two drugs target different cellular components and induce apoptosis by different pathways, and that resistance to DEX is associated with low levels of bcl-2, whereas resistance to MEL is independent of bcl-2, and therefore, in vivo resistance to MEL, observed in MM patients, might involve other mechanisms rather than bcl-2.

Collection, tumor contamination, and engraftment kinetics of highly purified hematopoietic progenitor cells to support high dose therapy in multiple myeloma

Unfractionated peripheral blood stem cell (PBSC) grafts contain measurable quantities of myeloma cells and are therefore a potential source of relapse posttransplantation. In contrast, fluorescence-activated cell sorting (FACS)-sorted CD34+ Thy1+ Lin- peripheral blood cells are substantially enriched for stem cell activity, yet contain virtually no clonal myeloma cells. A study was performed in patients with symptomatic myeloma, who had received 12 months or less of preceding standard chemotherapy, to evaluate the feasibility of large scale purification of primitive hematopoietic stem cells in order to study engraftment kinetics posttransplantation and the degree of tumor cell contamination of this cell population, based on polymerase chain reaction (PCR) analysis for the patient-specific complementarity-determining region III (CDR III). PBSC were mobilized with high dose cyclophosphamide and granulocyte-macrophage colony-stimulating factor (GM-CSF). A combination of elutriation and chemical lysis was used to deplete PBSC collections of monocytes, granulocytes, erythrocytes, and platelets. Subsequently, CD34+ Thy1+ Lin- progenitor cells were purified with high speed cell sorting. Of the 10 evaluable patients, nine met the required minimum criteria of >/=7.2 x 10(5) cells/kg to support tandem transplants. After high dose melphalan (200 mg/m2) eight engrafted successfully, although granulocyte (absolute neutrophil count [ANC] >0.5 x 10(9)/L, 16 days) and platelet recovery (platelets > 50 x 10(9)/L, 39 days) was substantially delayed when compared with unmanipulated PBSC grafts; one patient required infusion of a reserve graft because of lack of evidence of engraftment by day +28. Three patients proceeded to a second graft with high dose melphalan and total body irradiation; two required infusion of a reserve graft and both died of infectious complications; one showed delayed, but complete, engraftment after this myeloablative regimen. Two of the nine evaluable patients attained a clinical complete remission (CR). The grafts from three patients were tested for tumor contamination and contained no detectable clonal myeloma cells. Larger quantities of purified cells may be required to resolve the problem of delayed engraftment.

Fas (APO-1/CD95)-mediated apoptosis is independent of bcl-2: a study with cell lines overexpressing bcl-2 and with bcl-2 transfected cell lines

Eight myeloma cell lines with variable expression of bcl-2 were screened for the expression of the FAS antigen and for sensitivity to anti-FAS-induced apoptosis. Anti-FAS-induced apoptosis correlated positively (R = 0.89) with the level of expression of the FAS antigen, and was independent of the expression of bcl-2. Forced expression of bcl-2 in 8226 and ARP-1 multiple myeloma (MM) cell lines expressing relatively low levels of bcl-2, resulted in 1-2 log increase in resistance to dexamethasone (DEX)-induced apoptosis. However, sensitivity to anti-FAS-induced apoptosis was unchanged in ARP-1 cells or was increased in 8226 cells, compared to the parental cell lines. The increased sensitivity to anti-FAS-induced apoptosis in 8226 cells was due to the increase in FAS expression in the bcl-2 transfected cells and was proportionate to the increase in FAS expression. Furthermore, we observed manyfold increase in the expression of Fas, CD40, CD45 and CD19 antigens, in 8226 cells, concomitant with a significant decrease in the expression of CD38 antigen. Thus, 8226 cells overexpressing bcl-2 appear to have an immature myeloma cell phenotype, have higher growth-rate and increased sensitivity to anti-FAS-induced apoptosis.

Pitfalls in the RNA-based PCR amplification of the CDRIII sequence for quantitation of minimal residual disease in multiple myeloma (Commentary)

The uniqueness of the complementarity determining region III (CDRIII) has been utilized successfully in the last decade for development of a patient specific, molecular, polymerase chain reaction (PCR)-based assay for determining minimal residual disease in various lymphoid malignancies. There are various approaches for carrying out this test. i) CDRIII primers are used to amplify the corresponding DNA from the same patient and quantitation of the amplified CDRIII bands is done by generation a standard curve of known amounts of purified patient's tumor DNA, followed by a linear regression analysis to quantitate the results. ii) CDRIII primers are used to amplify a serially-diluted patient's sample (unknown), with replicate points. According to Poisson equation, replicate points in each dilution can be either all positive, all negative, or 'mixed', negative and positive. The quantitation, according to this approach is done by determination of the dilution point where there are 'mixed' lanes plus the flanking 'all negative' and 'all positive' lanes, assuming that the test can always detect one tumor cell in 100,000 cells. In this communication we show evidence that the use of the Poisson method can lead to an underestimation of the amount of tumor cells, due to the great variability in the priming and amplification among the various CDRIII primers. This variation is inherent to the size, C/G ratio, melting point of each primer, etc. In a simulated statistical model we show that the magnitude of error in the Poisson method could reach 1-2 logs. In contrast, using the standard curve for each patient and regression analysis eliminate these problems.

Intracellular distribution of heat-induced stress glycoproteins

Cellular heat stress results in elevated heat-shock protein (HSP) synthesis and in thermotolerance development. Recently, we demonstrated that protein glycosylation is also an integral part of the stress response with the identification of two major stress glycoproteins, GP50, associated with thermotolerance, and P-SG67, the "prompt" stress glycoprotein induced immediately during acute heat stress. In the present study, we characterized the subcellular location and redistribution of these proteins during the cellular injury and recovery phase. In unheated and heated CHO cells, both stress glycoproteins were present in each subcellular fraction isolated by differential centrifugation. However, the subcellular redistribution in the course of cellular recovery after heat stress was specific for each stress glycoprotein. GP50 was present in all subcellular fractions before heat stress, but showed relatively little redistribution after heat stress. By 24 h of recovery following stress, GP50 showed partial depletion from lysosomes and microsomes, and was mainly present in the mitochondria. Glycosylated P-SG67 was redistributed in a more complex fashion. It was seen predominantly in the lysosomes and microsomes immediately following heat-stress, but after 6 h of recovery following heat stress, it largely disappeared from the microsomes and was present mainly in the cytosol. By 24 h of recovery following heat stress, it was found predominantly in the nucleus-rich fraction and mitochondria. The localization of GP50 and P-SG67 by subcellular fractionation is consistent with immunolocalization studies and contrasts with the translocation of HSP70 after heat stress from cytosol to nuclei and nucleoli. These results reflect a characteristic distribution for each stress glycoprotein; their presence in virtually all subcellular fractions suggests multifunctional roles for the various stress glycoproteins in the cellular heat stress response.

Autologous transplantation with tumor-free graft: a model for multiple myeloma patients

The importance of obtaining a tumor-free graft for autologous transplantation in cancer patients has been debated extensively in the last decade and is still unresolved largely because it is believed that relapse is more likely to originate from the host and not from the graft. This is in spite of recent indications that the main source of relapse is the graft. In this review article we bring forward evidence that the currently used grafts, whether from peripheral blood or bone marrow, harbour significant number of tumor cells before and even after purging with currently available purging protocols. We believe that the use of a tumor-free graft is the only way to obtain a valid assessment of the efficacy of high dose radio-chemotherapy, and is the only methodology to increase the probability to achieve long term survival following AT. Accordingly, we describe in detail a procedure to obtain a tumor-free graft, designed for the treatment of multiple myeloma patients based on flow-sorting of CD34+ stem cells.

Differential mobilization of myeloma cells and normal hematopoietic stem cells in multiple myeloma after treatment with cyclophosphamide and granulocyte-macrophage colony-stimulating factor

Peripheral blood stem cells (PBSCs) mobilized with high-dose chemotherapy and hematopoietic growth factors are now widely used to support myeloablative therapy of multiple myeloma and effect complete remissions in up to 50% of patients with apparent extension of event-free and overall survival. Because tumor cells are present not only in bone marrow, but also in virtually all PBSC harvests, it is conceivable that autografted myeloma cells contribute to relapse after autotransplants. In this study, the kinetics of mobilization of normal hematopoietic stem cells were compared with those of myeloma cells present in PBSC harvests of 12 patients after high-dose cyclophosphamide and granulocyte-macrophage colony-stimulating factor administration. CD34+ and CD34+Lin-Thy+ stem cell contents were measured by multiparameter flow cytometry, and myeloma cells were quantitated by immunostaining for the relevant Ig light chain and by a quantitative polymerase chain reaction for the myeloma-specific CDRIII sequence. Results indicated marked heterogeneity in the percentages of mobilized stem cells among different patients (0.1% to 22.2% for CD34+ cells and 0.1% to 7.5% for CD34+Lin-Thy+ cells, respectively). The highest proportions of hematopoietic progenitor cells were observed early during apheresis, with 9 of 12 patients mobilizing adequate amounts of CD34+ cells for 2 autotransplants (> 4 x 10(6)/kg) within the first 2 days, whereas peak levels (percent and absolute numbers) of myeloma cells were present on days 5 and 6 (0.5% to 22.0%). During the last days of collection, mobilized tumor cells exhibited more frequently high labeling index values (1% to 10%; median, 4.4%) and an immature phenotype (CD19+). The differential mobilization observed between normal hematopoietic stem cells and myeloma cells can be exploited to reduce tumor cell contamination in PBSC harvests.

Purified CD34+ Lin- Thy+ stem cells do not contain clonal myeloma cells

High-dose therapy with autologous marrow or peripheral blood stem cell (PBSC) rescue has been extensively applied in the treatment of multiple myeloma (MM) patients during the past 10 years resulting in improved event-free and overall survival when compared with standard chemotherapy. However, relapses are common and cure is unlikely in the majority of patients. Because both bone marrow and PBSCs are contaminated with myeloma cells it is conceivable that relapse after autotransplantation originates at least in part from autografted tumor cells. In this study, mobilized PBSCs were examined for the presence of myeloma cells based on immunophenotyping and sensitive polymerase chain reaction (PCR)-based techniques. In addition, CD34+ Lin- Thy+ stem cells were purified from mobilized PBSC harvests of 10 MM patients by sequentially using counterflow elutriation centrifugation, treatment with phenylalanine methylester, and flow sorting, using 5-parameter gating (propidium iodide, forward scatter, side scatter, CD34+ v Lin- and CD34+ v Thy+). Virtually all mobilized unsorted PBSC preparations contained myeloma cells in sufficient quantities (range, < 0.01 to > 10%) potentially causing a disease relapse. Stem cell purification led to an overall enrichment by about 50-fold in all 10 patients; approximately 90% of the final cell population expressed CD34+ Lin- Thy+ with no evidence of myeloma cell contamination based on flow cytometric analysis of CD38bright cells (< 0.1%). Quantitative PCR amplification of patient-specific complementarity determining region III (CDRIII) DNA sequences showed depletion of clonal B cells by 2.7 to 7.3 logs, with the highest log reduction noted in the samples initially containing the most tumor cells. Our results show that purification of CD34+ Lin- Thy+ cells depletes myeloma cells to undetectable levels from up to 10% present in unsorted PBSCs, thus offering a tool to investigate whether MM relapse after autotransplantation can be reduced markedly.

Aromatic retinoid Acid-derivatives are potent inducers of differentiation of neuroblastoma-cells - structure-function relationship and the involvement of the nuclear retinoic Acid receptors

Twenty-two derivatives of retinoic acid (RA) were tested for their potency to induce in vitro morphological differentiation of SK-N-SH neuroblastoma cell line at concentration range of 0.1 nM to 10 muM. The results indicate that three derivatives Ro-13-4306; Ro-13-6307 and Ro-13-7410 were potent inducers of differentiation at 3-4 log lower concentration compared to all trans retinoic acid (ATRA). Other compounds such as Ro-08-8717 and Ro-40-6055, were totally inactive, and with the majority of compounds inducing differentiation at concentrations comparable to ATRA. Fourteen compounds were studied for their hydrophobicity properties and the empirical hydrophobicity index (EHI) was derived from the retention time on an HPLC reverse column. Most of the EIH values derived for the compounds tested fell within the expected differentiation potency (ID50) range. However, ATRA and 9-cis RA fell below the expected curve, i.e. were less active than predicted by their hydrophobicity properties, whereas Ro-13-6307 and Ro-13-4306 fell above the curve, and thus were more potent in inducing differentiation than was predicted from their hydrophobicity properties. Energy minimized molecular models for the theoretical crystal structures were also reconstructed by computer modelling for five compounds. The molecular models of the two most active compounds (13-4306 and 13-6307) had almost identical crystal structure which was slightly different from that of the less active compounds, ATRA and 13-7410. SK-N-SH cell line expressed mRNA transcripts for the nuclear RA receptor-alpha (RARalpha) and did not express the RARbeta or RARgamma receptor. Induction of differentiation with ATRA, or with Ro-13-7410 did not change the pattern of expression of mRNA transcripts of any of the nuclear receptors tested. However, 13-4306 and 13-6307 markedly reduced the expression of the 2.4 kb mRNA band of RAR-alpha. These results, taken together, suggest the increased potency of 13-6307 and 13-4306 might be the result of a different splicing patterns of the RAR-alpha mRNA transcripts.

Enhancement of HBsAg detection in serum of patients with chronic liver disease following removal of circulating immune complexes

Patients with chronic liver disease and hepatocellular carcinoma may lack serological evidence of previous hepatitis B virus infection. The purpose of the present study was to test the hypothesis that circulating immune complexes may interfere with the detection of low levels of HBsAg in such patients. Sera from 190 patients were initially screened for the presence of circulating immune complexes. Patients belonged to three clinical categories: asymptomatic HBsAg carriers (50 patients), chronic liver disease (30 patients) and hepatocellular carcinoma (110 patients). Forty-one of the group of 190 patients (21%) were positive for circulating immune complexes. Sera from 21 patients were selected for further evaluation. The sera of 13 chronic liver disease or hepatocellular carcinoma patients (HBsAg negative, hepatitis B virus-DNA negative, with or without evidence of previous hepatitis B virus infection) and eight HBsAg positive carriers (four asymptomatic, three with chronic liver disease and one with hepatocellular carcinoma) were passed through a Clq affinity column (first column) to remove circulating immune complexes. Unbound material was then passed through a monoclonal IgG2a anti-HBs affinity column (second column). Unbound material (following both columns) contained free HBsAg, as determined by monocolonal radio-immunoassay, in eight patients in whom HBsAg had been undetectable in the original serum. Removal of circulating immune complexes from the serum of the three HBsAg positive patients with chronic liver disease also caused a significant increase in measurable circulating HBsAg compared with the original serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluctuations and ultrastructural localization of oncoproteins and cell cycle regulatory proteins during growth and apoptosis of synchronized AGF cells

AGF cells were synchronized by blocking the cell cycle at the G1/S boundary with high concentrations of thymidine (thymidine block) for 11 h. Prolongation of the thymidine block from 11 h to 20 h resulted in apoptosis. Early changes in cellular and nuclear morphology were monitored by confocal microscopy, transmission electron microscopy, and scanning electron microscopy. The fluctuations in the levels of the proliferation cell nuclear antigen (PCNA), cyclin A, CDC-2, c-myc, and p53 proteins were monitored in synchronized cultures and in cells undergoing apoptosis by immunofluorescence staining, flow cytometry, and Western immunoblotting. When assayed by immunofluorescence staining and flow cytometry, the levels of cyclin A and PCNA increased about 2-fold during the S phase, and the level of CDC-2 was fairly constant during S and slightly decreased during late S/G2. The level of c-myc also increased about 2-fold during the S phase, whereas the level of p53 increased only slightly during S. Most importantly, however, the level of staining for c-myc, p53, cyclin A, CDC-2, and PCNA increased 50%-150% during apoptosis compared to the levels observed in cells at G1/S. In contrast, the levels of actin and vimentin, although increased during S, were decreased during apoptosis compared to the levels observed at G1/S. Western blot analysis of the steady state levels of PCNA, cyclin A, and CDC-2 revealed an increase in the levels of all three proteins during S, with higher levels of these proteins observed in apoptotic cells compared to the levels observed in cells at G1/S. Similarly, the levels of p53 and c-myc proteins increased during S and were also high in apoptotic cells. Interestingly, high levels of these two proteins were observed also in cells arrested at G1/S. AGF cells undergoing apoptosis were immunostained for c-myc, p53, PCNA, cyclin A, and CDC-2 and were viewed by confocal microscopy. Apoptotic cells exhibited increased staining for c-myc and p53 in the blebbing nuclei. Furthermore, we observed for the first time that CDC-2, cyclin A, and PCNA proteins were associated mostly with the plasma membrane and the cytoplasm of log phase cells. However, in cells undergoing apoptosis, these proteins were found exclusively in the nuclei of apoptotic cells. These results suggest a possible active role for c-myc, p53, and the cell cycle regulatory proteins in the process of nuclear blebbing and apoptosis.

Fluctuations and nuclear translocation of p53, C-myc, cdc-2 and pcna proteins during growth and commitment to differentiation of agf cells

Transcription regulatory proteins such as c-myc and p53 play an important role in the regulation of cell growth, differentiation and apoptosis. Similarly, cell cycle regulatory proteins such as CDC-2, cyclin A and the proliferation cell nuclear antigen (PCNA), play an important role in regulation of cell growth. Yet, there are contradictory reports as for the exact mechanism by which these proteins affect antagonistic processes like growth, differentiation and apoptosis. In the present study, we report, for the first time a detailed analysis of the steady-state level and the nuclear/cytoplasmic distribution of oncoproteins and cell cycle regulatory proteins, in the early phase of PMA induced differentiation of AGF cells. Particular emphasis was put on the first 6 h of commitment to differentiation as well as on the committed/differentiated cells (24 h post induction). Using Western blots of protein extracted from the cytosolic, membranal and nuclear fraction we document an early intranuclear influx of p53 with concomitant extranuclear efflux of c-myc as early as 1-6 h post induction. Similarly, intranuclear sequestration of CDC-2 occurs throughout the commitment phase. General down regulation of p53 and partial down regulation of CDC-2, PCNA and c-myc occur in committed/differentiated cells (24 h post induction). The results obtained by Western blots were further supported by immunolocalization using confocal microscopy.

A safe procedure for transporting bone-marrow for purging in a central laboratory

A central facility for ex vivo removal of neuroblastoma cells from bone marrow, to be used for autologous reinfusion after myeloablative treatment, was established and a study was designed to compare the survival time and the rate of bone marrow engraftment between local marrows obtained and processed at the University of Florida (UF) and marrow transported for purging from out of state, participating Pediatric Oncology Group (FOG) centers. Marrow harvest from patients either at UF or at participating centers, was done under a similar protocol. Marrows from participating centers were transported by air, to UF and purged using the immunomagnetic technique. The purged marrows were returned in liquid nitrogen for reinfusion before myeloablative treatment. Marrows were purged between 1985 to 1992 from 169 POG patients, of whom 164 were evaluable for this study (UF 29 and 135 transported). Statistical analysis of survival time and engraftment rate found no significant differences in survival time (p=0.2463) and engraftment rate (0.3259) between marrows shipped from other institutions to marrows harvested and processed at UF.

Isolation and characterization of an early T-helper/inducer cell line with a unique pattern of surface phenotype, constitutive cytokine secretion and myc oncogene expression

The cell line AG-F was isolated from the marrow of a neuroblastoma patient undergoing myeloablative treatment and autologous bone marrow rescue. A year later, the patient developed a Hodgkin's type lymphoma. AG-F cell line demonstrated an unusual phenotype, lacking surface CD2 and CD3, but expressing high levels of CD4, CD5, CD7, CD29, and CD45RO. Markers associated with Hodgkin's lymphoma cells, CD15 and CD30, were also positive. AG-F cells grow in suspension in clusters of 50-200 cells, with a doubling time of 9 h. They can also grow in serum-free medium and form tumors in nude mice. AG-F cells have amplified N-myc and c-myc and high levels of the corresponding mRNA transcripts. Cytogenetic analysis revealed a DNA index by flow cytometry of near tetraploid cells and a karyotype of 85-87 chromosomes, with consistent abnormalities in chromosomes 1, 5, and 9. Gene rearrangement studies revealed rearrangement of the beta gene of the T-cell receptor. AG-F cells secrete high levels of IL-6, IL-8, IL-10, and GM-CSF. Cell adherence and formation of long processes could be induced by fibronectin and were enhanced by exposure to PMA. Cells exposed to phorbol myristate acetate (PMA) had increased expression of CD11a, CD11b, CD18, CD45RO, and HLA-DR, whereas expression of CD15 and CD30 was markedly decreased. Similarly, the level of c-myc and N-myc oncoproteins and the levels of the cytoskeletal proteins, actin, tubulin, and vimentin markedly decreased early after PMA-induced differentiation.

Regulation of cell-growth and apoptosis in synchronized agf cells - involvement of oncogenes and cell-cycle regulatory proteins

Cell synchrony was induced in AGF cells by blocking of the cell cycle at GI-S boundary with high concentrations (2 mM) of thymidine for 11 h. Prolonged arrest of cells in GI-S (15 h-20 h) induced progressive and time dependent apoptosis. Early morphological changes in cellular and nuclear morphology (blebbing) were monitored by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and by staining of nuclei with Hoechst and propidium iodide and stained cells viewed by fluorescence and confocal microscopy. The fluctuations in the levels of the proliferation cell nuclear antigen (PCNA), cyclin A, CDC-2, c-myc and p53 proteins were monitored in synchronized cultures and in cells undergoing apoptosis by immunofluorescence staining and flow cytometry. As expected, the levels of cyclin A and PCNA increased during the S phase and the level of CDC-2 decreased during late S/G2. Similarly, the level of c-myc increased during the S phase, whereas the level of p53 did not change much during S phase. Most importantly, however, the level of staining for c-myc, p53, cyclin A, CDC-2 and PCNA increased markedly during apoptosis. In contrast, the level of actin vimentin and tubulin, although increased during S phase, were markedly decreased during apoptosis. AGF cells stained for c-myc during apoptosis, and viewed by confocal microscopy, revealed increased staining for c-myc in the blebbing nuclei. These results, taken together, suggest a possible active role for c-myc in the process of nuclear blebbing and apoptosis.

Ultrastructural localization and fluctuation in the level of the proliferating cell nuclear antigen and myc oncoproteins in synchronized neuroblastoma cells

A method for rapid synchronization of neuroblastoma cells was developed using the thymidine block to arrest cells in the G1-S boundary. Following release from the thymidine block, cells traversed to G2-M in 7-8 h with 85% cell synchrony. Determination of the steady-state level of proliferating cell nuclear antigen (PCNA) mRNA and protein by Northern and Western blots revealed an accumulation of the PCNA messenger RNA transcripts and PCNA protein at G1-S and a rapid decrease when cells entered S phase. The level of both the messenger RNA transcripts and protein increased as the cells moved to late-S and G2-M. Similarly, the steady-state level of c-myc and N-myc messenger RNA transcripts and proteins increased during the G1-S block, decreased when the cells entered S, and increased as the cells moved through S phase to G2-M. However, immunofluorescence staining for PCNA and myc protein indicated a low level of staining for all three proteins at G1-S and a significant increase in staining intensity during S phase. Similarly, immunoelectron microscopy revealed low levels of N-myc and c-myc staining during G1-S and increased staining during mid-S and late S phase of the cell cycle. These results suggest differential cell cycle-dependent accessibility of myc protein and PCNA to staining in the intact cells compared to the whole cell extract. Furthermore, using immunofluorescence staining, confocal microscopy, and immunoelectron microscopy, we demonstrate for the first time that myc proteins are associated with the chromosomes during mitosis.

Down regulation of stem cell colony formation by purified CD8 lymphocytes and CD8 conditioned medium: potential importance for bone marrow transplantation in leukemia

A methodology for selection of the CD8 cell subset from the peripheral blood and bone marrow mononuclear cells was developed using anti-T8 (CD8) antibody and magnetic microspheres coated with anti-mouse IgG. Following optimization of antibody:cell binding ratio and microsphere:cell ratios, CD8(+)-cells in the peripheral blood and bone marrow were effectively removed, with an overall final recovery of 34.9% +/- 8.6%, and 56% +/- 8.5% respectively with complete recovery of stem cells and very little contamination with effector cells. CD8(+)-depleted cell preparations demonstrated a 3-4 fold increase in CFU-C and CFU-E colony formation over non-depleted preparations when stimulated with G-CSF, GM-CSF or IL-3 and erythropoietin. The largest increase in colony formation was evident when IL-3 was used to stimulate colony formation. Purified autologous CD8+ T-cells or culture supernatant from in vitro cultures of purified autologous CD8+ T-cells added back to CD8 depleted preparations, induced 20%-90% suppression of CFU-C and CFU-E colony formation in a dose dependent manner. Colony formation by CD34+ cells, purified by anti CD34 antibodies and magnetic microspheres, were also inhibited by either pure CD8(+)-cell populations or CD8-culture supernatant. Preliminary fractionation studies indicate that the inhibitory factor is a protein of > 50 kd. In contrast, when purified autologous CD4+ cells were added to purified CD34+ stem cells, an increase (< 50%) in colony formation was observed. These results, taken together, suggest that CD8+ T-cells are negative effectors of normal hematopoiesis whereas CD4+ T-cells function as positive effectors.

Expression of N-myc, c-myc, and MDR-1 proteins in newly established neuroblastoma cell lines: a study by immunofluorescence staining and flow cytometry

A methodology for rapid isolation of neuroblastoma cells from marrow with metastatic neuroblastoma cells was developed using a cocktail of five antibodies and magnetic microspheres coated with secondary antibodies. Cells bound to microspheres were released by brief exposure to chymopapain, followed by repeated culture of released cells in serum-supplemented Dulbecco's modified Eagle's medium and selection for adherent cells. Using this methodology, over 35 primary cell lines were obtained free of contaminating normal cells. Detailed analyses of over 14 cell lines revealed gross differences in cell phenotype, size, morphology development of neurite processes, and doubling time (40 to 80 h). All cell lines expressed the M(r) 145,000 neurofilament, and a few expressed the M(r) 200,000 neurofilament, with very little or no expression of the M(r) 68,000 neurofilament. Eight % of all cells lines had near-diploid DNA content. High expression of the MDR-1 protein was detected in six of the 22 cell lines tested. Great heterogeneity was observed in the expression of N-myc oncoprotein, with ten of 13 patients overexpressing the protein. c-myc oncoprotein was also expressed in all cell lines; however, the level of expression was 4- to 10-fold lower than the N-myc oncoprotein. Localization studies of c-myc and N-myc oncoproteins on the level of light microscopy and electron microscopy revealed exclusive nuclear localization of c-myc, whereas N-myc was localized to the nucleus and to the cytoplasm.

Development of a two color immunofluorescence stain and immunolocalization method for N-myc and c-myc oncoproteins with a newly generated mouse IgM anti N-myc antibody

A new mouse monoclonal antibody specific for N-myc oncoprotein was generated and used in combination with an anti-c-myc antibody to develop two color immunofluorescence staining and ultrastructural immunolocalization of N-myc and c-myc in well established (SK-N-SH; CHP 126) and in newly established neuroblastoma (NB) cell lines. Analysis and quantitation of c-myc and N-myc in dually stained cells was done by flow cytometry. Immunolocalization was done by staining with immunogold secondary antibodies and transmission electron microscopy. The results obtained from analysis of 13 newly established NB cell lines revealed, great heterogeneity in the expression of N-myc oncoprotein with 10/13 cell lines over expressing the protein. C-myc oncoprotein was also expressed in all cell lines, however, the level of expression was 4-10-fold lower than the N-myc oncoprotein. Localization studies of c-myc and N-myc oncoproteins on the level of light microscopy and electron microscopy revealed exclusive nuclear localization of c-myc whereas N-myc was localized to the nucleus and to the cytoplasm.

A novel methodology for the establishment of neuroblastoma cell lines from metastatic marrow

A methodology for rapid isolation of neuroblastoma (NB) cells from marrow with metastatic NB cells was developed using a cocktail of five antibodies and magnetic microspheres coated with secondary antibodies. Cells bound to microspheres were released by brief exposure to chymopapain, followed by repeated culture of released cells in serum supplemented DMEM medium and selection for adherent cells. Using this methodology, over 35 primary cell lines were obtained free of contaminating normal cells. Detailed analyses of over 14 cell lines revealed gross differences in cell phenotype, size, morphology development of neurite processes, and doubling time (40h-80 h). All cell lines expressed the 145 kDa neurofilament (NF) and a few expressed the 200 kDa NF, with very little or no expression of the 68 kDa NF. DNA analyses revealed 80% near diploid cell lines. High expression of the MDR-1 protein was detected in 6/22 of the cell lines tested.

Clinical and flow cytometry characteristics of malignant pleural effusions in patients after intracavitary administration of methylprednisolone acetate

Ten patients with recurrent pleural effusions due to advanced cancer were treated by intracavitary methylprednisolone acetate (Depo-Medrol [DM], Upjohn, Kalamazoo, MI). They received one to six courses of DM (median, three courses per patient) with doses ranging from 80 to 160 mg per course. Effusion cells were cryopreserved before and during DM installation for subsequent determination of ploidy by flow cytometry. Pleural effusion in all three patients with advanced breast cancer resolved and did not reaccumulate throughout follow-up for 11+, 10+, and 8+ months. Pleural effusion in a patient with metastatic gastric cancer and in two of four patients with adenocarcinoma of unknown origin partially resolved. Altogether six of ten patients (60%) subjectively and objectively benefited from this therapy. All patients tolerated the treatment well with no local or systemic side effects. Flow cytometry showed a reduction in ploidy of effusion cells in all three patients with breast cancer, from a peak mean channel of 6C to nearly 2C after therapy. Transient reduction of ploidy was seen also in the effusion of a patient with unknown primary tumor associated with clinical improvement. The clinical and laboratory data reported offers initial evidence that DM when instilled into the pleural cavity after incomplete thoracentesis may act as effective palliative therapy either alone or in combination with other anticancer agents.

Electro-insertion of xeno-glycophorin into the red blood cell membrane

The electroporation technique, with field strengths slightly below the critical value Ec for electroporation of red blood cells (RBC), enables the insertion of xeno-proteins into the RBC membrane without damaging the cells. The electro-insertion has been used to insert biotinylated human glycophorin into human RBC membrane and human glycophorin into murine RBC membrane. Binding anti-human glycophorin antibody (10F7) to the murine RBC bearing human glycophorin indicates extracellular orientation of inserted glycophorin. Insertion of about 10(5) glycophorin molecule per cell has been estimated by whole cell ELISA.

Improvement of immune-complex nephritis associated with hepatitis B surface antigen excess

A case of hypocomplementemic membranoproliferative glomerulonephritis was studied during remission of nephrosis induced by high doses of corticosteroids. Hepatitis B surface antigen (HBsAg) and immune complexes were detected in serum and glomeruli. Anti-hepatitis-B surface antibody, undetectable in serum by conventional radioimmunoassays was identified in circulating immune complexes (CIC). On two occasions, improvement in renal function coincided paradoxically with an extreme increase in serum HBsAg levels as well as with marked elevation of CIC. We suggest that, as previously observed in animal models of glomerulonephritis, extreme antigen excess may inhibit glomerular deposition of immune complexes.