Guidelines for clinical protocols for chronic lymphocytic leukemia: recommendations of the National Cancer Institute-sponsored working group

The National Cancer Institute (NCI)-sponsored Chronic Lymphocytic Leukemia (CLL) Working Group was convened to develop a set of standardized eligibility, response, and toxicity criteria for clinical trials. We recognized the previous efforts in 1967 (published again in 1973 as the report of the Chronic Leukemia-Myeloma Task Force [1] and 1978 of Cancer and Leukemia Group B (CALGB) [2]). We have used these reports for guidance during the current effort. Several noteworthy developments in the past few years have made it necessary to modify the previous guidelines. First, the diagnostic criteria for CLL and its clinical staging have been developed and well defined. Second, although staging systems facilitated entry of comparable and relatively homogeneous groups of patients in clinical trials, the definitions of response (CR) and partial response (PR) were not uniformly adopted from the previous guidelines in the clinical trials (Tables IA, IB); therefore, comparisons of results obtained in different studies became difficult. Third, there has been an improvement in our understanding of the immunology and biology of CLL. Finally, we are witnessing the emergence of several chemotherapy agents that promise impressive activity in CLL (e.g., 2'-deoxycoformycin [3], fludarabine monophosphate [4, 5]), and thereby offer the potential for improving survival time in this disease. To best identify regimens worthy of continued pursuit in large comparative trials, standardized guidelines for evaluation are essential. A number of laboratory investigations are also presented for which scientific interest is high yet relevance remains to be determined; thus, they are presented as companion studies to the clinical trials. This mechanism allows for flexibility in the testing of these questions and for additional ideas in the future without requiring modification of an entire treatment protocol. The following guidelines were developed to be used as a form of standardization for clinical trials, incorporating current technologies, yet remaining relevant to the general hematology/oncology community. Based on the membership of the Working Group, it is expected that these guidelines will serve as the criteria for most clinical trials in the near future.

A phase II study of interleukin-2 and lymphokine-activated killer cells in patients with metastatic malignant melanoma

Thirty-six patients with metastatic melanoma were entered into a study of the therapeutic efficacy of adoptive immunotherapy with high-dose interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells. Thirty-two patients who received all components of the therapy are evaluable for response, and all patients are evaluable for toxicity. Sites of disease included lung, liver, subcutaneous nodules, and intra-abdominal metastases. One complete response (CR) and five partial responses (PRs) resulted from treatment (19% response rate). The median response duration was 5 months, with the durable CR continuing at 31+ months and one durable PR continuing for 13 months. Sites of response included lung, liver, subcutaneous nodules, and lymph nodes. Response, response duration, or site of response did not correlate with the total dose of IL-2 administered, rebound lymphocytosis, or the number of LAK cells infused. Toxicity included hypotension, fluid retention with a "capillary leak syndrome" in most patients, and transient multiorgan dysfunction that resolved promptly after the completion of therapy. Adverse cardiac events occurred in 16% of patients, with one myocardial infarction leading to a death. This study confirms the activity of the initial IL-2/LAK cell regimen in metastatic melanoma reported by Rosenberg et al, supporting the concept of adoptive immunotherapy as an important new treatment approach for this disease.

Excretion of deoxyribonucleic acid by lymphocytes stimulated with phytohemagglutinin or antigen

When human lymphocytes are cultured in the presence of phytomitogens, 70-90% of the cells undergo blast transformation and synthesize DNA. However, less than 40% of these lymphocytes actually undergo mitosis while 35-90% of the newly synthesized DNA is excreted into the media. The release of DNA by the cells is selective since experiments with [(14)C]uridine indicate that RNA is not lost into the culture media. DNA excretion occurs under many culture conditions. The excreted DNA has an estimated molecular weight of 3 to 12 x 10(6) as determined by gel filtration on Sepharose 2B. It forms a single sharp peak at a density of 1.055 g/cm(3) when examined by sucrose density gradient centrifugation, suggesting that the DNA is complexed to protein or lipid.

A randomized phase II trial of continuous infusion interleukin-2 or bolus injection interleukin-2 plus lymphokine-activated killer cells for advanced renal cell carcinoma

PURPOSE

Since 1985, multiple centers have demonstrated that interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells produce durable anticancer responses in patients with metastatic renal cell carcinoma. High-dose recombinant IL-2 (rIL-2) has been administered by intravenous bolus injection (Rosenberg SA, et al: N Engl J Med 313:1485-1492, 1985) and by continuous intravenous infusion (West WH, et al: N Engl J Med 316:898-905, 1987) combined with lymphokine-activated killer (LAK) cells, with both methods producing responses in patients with advanced renal cell carcinoma. The Extramural IL-2/LAK Working Group has conducted a randomized phase II trial of two intravenous high-dose rIL-2 regimens (bolus three times daily or 24-hour continuous infusion) to determine if either one manifests greater anticancer activity or a more acceptable toxicity profile.

PATIENTS AND METHODS

Ninety-four patients with measurable advanced renal cell carcinoma were enrolled on this study: 46 to the bolus injection arm and 48 to the continuous infusion arm. On both arms, patients underwent a priming phase of rIL-2 administration, four daily lymphocytaphereses to harvest mononuclear cells that were placed in 3- to 4-day culture for generation of LAK cells, and an rIL-2/LAK coadministration phase. Patients were then observed monthly for evidence of response to this therapy and were offered up to two additional courses of treatment every 3 months if evidence of response was detected.

RESULTS

Twenty percent of patients on the bolus injection arm experienced objective responses (three complete responses and six partial responses); 15% of patients on the continuous infusion arm responded (two complete responses and five partial responses). Complete responses were durable, persisting for 310+ to 700+ days. The incidence of severe life-threatening toxicities typical of high-dose rIL-2 therapy was similar in both arms (eg, patients with hypotension requiring pressors: bolus 71%, continuous 63%; oliguria less than or equal to 200 mL/8 hours: bolus 65%, continuous 71%). More episodes of fever, infection, and serum alkaline phosphatase elevation were associated with the continuous infusion arm, while more thrombocytopenia occurred on the bolus injection arm. Four patients (three bolus injection, one continuous infusion) died of respiratory and circulatory failure while under treatment. No clinical or laboratory parameter accompanying treatment on either arm was, by univariate or multivariate analysis, associated with an increased likelihood of response.

CONCLUSIONS

Both methods of high-dose rIL-2/LAK cell administration produce nearly equivalent anticancer activity and toxicity in the treatment of renal cell carcinoma. The ability to predict responding patients based on patient or treatment characteristics is not possible.

A phase II study of high-dose continuous infusion interleukin-2 with lymphokine-activated killer cells in patients with metastatic melanoma

Thirty-three patients with metastatic melanoma were treated in a phase II study with an intravenous continuous infusion (IVCI) of interleukin-2 (IL2) given with lymphokine-activated killer (LAK) cells. The dose of IL2 was the optimal priming dose for LAK-cell induction, followed by the maximally tolerated LAK-cell dose that could be given by an IVCI schedule as determined by a previous phase I trial. The CI schedule was chosen for evaluation because of a postulated reduction in toxicity with the possibility of administering a more prolonged IL2 infusion and because greater rebound lymphocytosis and LAK-cell generation had been reported using this dose and schedule. The 33 patients were similar in age, performance status, and sites of disease to those treated in previous IL2 trials. All patients were assessable for response and toxicity. One patient (3%) achieved a partial response of 10 months duration. There were no other clinically significant responses. Significant toxicity included hypotension requiring pressors (45%), dyspnea (36%), renal insufficiency (24%), hepatic dysfunction (66%), and cardiac arrhythmias (18%). These toxicities reversed with cessation of the infusion. There were four deaths during the first 30 days of treatment, three from infection (one related to central line, one related to LAK cells, one related to tumor), and one from tumor-related hemorrhage. Toxicity was unexpectedly high and at least comparable to that seen in previous studies using a high-dose IV bolus schedule of IL2. When comparing the IVCI schedule with high-dose bolus IL2 to LAK cells in nonrandomized but sequential studies in patients with advanced melanoma, it appears that CI IL2 is less efficacious.

Characterization of the mouse tartrate-resistant acid phosphatase (TRAP) gene promoter

Tartrate-resistant acid phosphatase (TRAP) is an iron-binding protein that is highly expressed in osteoclasts. To characterize the regulation of TRAP gene expression, progressive 5' and 3' deletions of a 1.8 kb fragment containing the 5'-flanking sequence were fused to a luciferase reporter gene. Two nonoverlapping regions of this 1.8 kb fragment had promoter activity. The upstream promoter (P1) was located within the region from -881 bp to -463 bp relative to the ATG, while the downstream promoter (P2) was located between -363 bp to -1 bp in a region we have previously shown to be an intron in transcripts originating from the upstream promoter. A putative repressor region for the P2 promoter at -1846 bp to -1240 bp and a putative enhancer region at -962 bp to -881 bp relative to the ATG were identified. PCR analysis of promoter-specific transcription of the TRAP gene in various murine tissues showed that both promoters were active in several tissues. Transferrin-bound iron increased P1 promoter activity 2.5-fold and hemin decreased P1 promoter activity, but neither had any effect on P2 activity. These data show that the transcriptional regulation of the TRAP gene is complex and that iron may play a key role in TRAP gene regulation.

Metastatic malignant melanoma treated with combined bolus and continuous infusion interleukin-2 and lymphokine-activated killer cells

Fifty patients with advanced melanoma received high-dose bolus and continuous infusion interleukin-2 (IL-2) with lymphokine-activated killer (LAK) cells in an attempt to improve the therapeutic index of this active but toxic therapy. Treatment began with up to nine bolus doses of IL-2 administered over 3 days. After 1 day of rest, patients underwent daily leukapheresis for 4 days, and the leukocytes were cultured with IL-2 in vitro to prepare LAK cells. Continuous infusion IL-2 was begun 1 day after the last leukapheresis and continued for up to 148 hours; LAK cells were administered on days 1, 2, and 4 of the infusion. Responding patients were eligible to receive up to two additional cycles of therapy at 3-month intervals. Most patients completed each cycle without dose reduction. One patient had a complete response and six patients had partial responses (14% response rate). The complete responder and three of the partial responders (8%) remain free from disease progression with follow-up of 21 to 24 months. Of these four patients with durable remissions, one had extensive liver and lymph node metastases, one had lymph node, pleural, and parenchymal lung metastases, and two had disease limited to lymph nodes or subcutaneous tissues. Seventeen patients (34%) required pressors for hypotension, three patients (6%) developed hemodynamically significant arrhythmias, and six patients (12%) developed dyspnea at rest, but none required intubation and there were no treatment-related deaths. Unacceptable toxicity developed in two patients during bolus IL-2 administration and therapy was aborted; both returned to baseline status within 4 days of discontinuing IL-2. Fever, oliguria, and elevated creatinine or transaminase levels occurred frequently but were also transient. Despite less frequent severe toxicity with this modified regimen, these results confirm the ability of IL-2 and LAK cell therapy to induce durable remissions in some patients with advanced melanoma.

Computed tomographic study of children with classic autism

Computed tomographic (CT) scans were obtained for nine autistic boys aged between 9 and 16 years. All were considered to have classic childhood autism of unequivocal diagnosis, with symptoms present from infancy, and were functioning in the borderline or normal level of intelligence. They had performed poorly on tests purported to measure left hemispheric functions. There was no sign of abnormality of any kind on the CT scans or any asymmetry that might be related to lateralized cognitive functions. It is suggested that earlier reported abnormalities are a function of the inclusion of patients with a heterogeneous collection of disorders in the tested sample.

Expression of different NF-kappaB pathway genes in dendritic cells (DCs) or macrophages assessed by gene expression profiling

NF-kappaB/Rel transcription factors have been implicated in the differentiation of monocytes to either dendritic cells (DCs) or macrophages, as well as in the maturation of DCs from antigen-processing to antigen-presenting cells. Recent studies of the expression pattern of Rel proteins and their inhibitors (IkappaBs) suggest that their regulation during this differentiation process is transcriptional. To investigate differential gene expression between macrophages and DCs, we used commercially available gene microarrays (GEArray KIT), which included four of the NF-kappaB/Rel family genes (p50/p105, p52/p100, RelB, and c-rel) and 32 additional genes either in the NF-kappaB signal transduction pathway or under transcriptional control of NF-kappaB/Rel factors. To generate macrophages and DCs, human adherent peripheral blood monocytes were cultured with M-CSF or GM-CSF + IL-4 respectively for up to 8 days. DCs (and in some experiments, macrophages) were treated with lipopolysaccharide (LPS) for the last 48 h of culture to induce maturation. Cells were harvested after 7 days, cDNA was prepared and radiolabeled with alpha-(32)P-dCTP, then hybridized to gene arrays containing specific gene probes. beta-actin and GAPDH or PUC18 oligonucleotides served as positive or negative controls, respectively. The expression of all four NF-kappaB/Rel family genes examined was significantly upregulated in maturing DCs compared to macrophages. The strongest difference was observed for c-rel. RT-PCR determinations of c-rel, RelB, and p105 mRNAs confirmed these observations. Among the 32 NF-kappaB/Rel pathway genes, 14 were upregulated in mature DCs compared to macrophages. These genes were IkappaBalpha, IKK-beta, NIK, ICAM-1, P-selectin, E-selectin, TNF-alpha, TNFR2, TNFAIP3, IL-1alpha, IL-1R1, IL-1R2, IRAK, and TANK. By contrast, only mcp-1 (monocyte chemotactic protein 1) was upregulated in macrophages compared to DCs. NF-kappaB pathway genes upregulated in DCs compared to macrophages were constitutively expressed in monocytes then selectively downregulated during macrophage but not DC differentiation. LPS did not induce expression of most of these genes in macrophages but LPS did induce upregulation of IL-8 in mature macrophages. We conclude that NF-kappaB/Rel family genes, especially c-rel, are selectively expressed during differentiation of monocytes towards DCs. Moreover, this differential expression is associated both with activation of different NF-kappaB signal transduction pathways in DCs and macrophages and with expression of a unique subset of genes in DCs that are transcriptionally targeted by NF-kappaB/Rel factors. The results illustrate the ability of the NF-kappaB pathway to respond to differentiation stimuli by activating in a cell-specific manner unique signalling pathways and subsets of NF-kappaB target genes.

New perspectives on iron: an introduction

Iron is an essential nutritional element for all life forms. Iron plays critical roles in electron transport and cellular respiration, cell proliferation and differentiation, and regulation of gene expression. Two emerging new functions for iron are its necessary role in supporting transcription of certain key genes required for cell growth and function [eg, nitric oxide synthase, protein kinase C-beta, p21 (CIP1/WAF1)] and its complex role in hematopoietic cell differentiation. However, iron is also potentially deleterious. Reactive oxygen species generated by Fenton chemistry may contribute to major pathological processes such as cancer, atherosclerosis, and neurodegenerative diseases. Iron-generated reactive oxygen species may also function in normal intracellular signaling. Therefore, roles of iron are both essential and extraordinarily diverse. This symposium explores this diversity by covering topics of iron absorption and transport, the regulation of gene expression by iron responsive proteins, the cellular biology of heme, hereditary hemochromatosis, and clinical use of serum transferrin receptor measurements.

Transcriptional regulation of the tartrate-resistant acid phosphatase (TRAP) gene by iron

Tartrate-resistant acid phosphatase (TRAP) was first identified in cells from patients with hairy cell leukaemia. Subsequently, it has been found in other leukaemias, B-lymphoblastoid cell lines, osteoclasts and subsets of normal lymphocytes, macrophages, and granulocytes. Recent data indicate that TRAP and porcine uteroferrin, a placental iron-transport protein, represent a single gene product. However, the intracellular role of TRAP is unknown. We used a full-length human placental TRAP cDNA probe to examine TRAP expression in human peripheral mononuclear cells (PMCs). TRAP mRNA increased 50-75-fold after 24 h in unstimulated PMC cultures. Cell-fractionation experiments indicated that monocytes were the main cell population accounting for increased TRAP mRNA transcripts, and this was confirmed by histochemical staining for TRAP enzyme activity. Because expression of other iron-binding and -transport proteins is controlled by iron availability, we examined the role of iron in regulating TRAP expression. Increase of TRAP mRNA transcripts in PMCs was inhibited by 50 microM desferrioxamine, a potent iron chelator. The 5' flanking region of the TRAP gene was cloned from a mouse genomic library. In preliminary transient transfection experiments, it was determined that the 5'-flanking region of the TRAP gene contained iron-responsive elements. Therefore, a series of stably transfected HRE H9 cell lines was developed bearing genetic constructs containing various segments of the murine TRAP 5' promoter region driving a luciferase reporter gene. Treatment of transfectants with 100 micrograms/ml iron-saturated human transferrin (FeTF) was performed to assess iron responsiveness of the constructs. Constructs containing a full-length TRAP promoter (comprising base pairs -1846 to +2) responded to FeTF with a 4-5-fold increase of luciferase activity whereas constructs containing only base pairs -363 to +2 of the TRAP promoter did not respond. Constructs containing 1240 or 881 bp of the TRAP promoter gave only a 1.5- to 2-fold increase of luciferase activity with FeTF. In all cases, increase of luciferase activity was blocked by desferrioxamine. Cells transfected with another luciferase construct driven by a simian virus 40 promoter did not show any increase of luciferase activity with FeTF. These data indicate that expression of TRAP is regulated by iron and that this regulation is exerted at the level of gene transcription. The transfection experiments also suggest that the region of the TRAP 5'-flanking sequence between base pairs -1846 and -1240 contains an iron regulatory element.

Comparison of the L10M consolidation regimen to an alternative regimen including escalating methotrexate/L-asparaginase for adult acute lymphoblastic leukemia: a Southwest Oncology Group Study

The effectiveness of intensive post-remission chemotherapy regimens for adult patients with acute lymphoblastic leukemia (ALL) is limited by both a high rate of disease recurrence and a substantial incidence of treatment toxicity. To evaluate a potentially more effective and less toxic approach, we conducted a multicenter phase III trial of consolidation therapies comparing the standard L10M regimen with one combining the brief, intensive L17M regimen and escalating methotrexate (MTX) and L-asparaginase (L-asp). Patients over age 15 with previously untreated ALL were eligible. Induction therapy included vincristine, prednisone, doxorubicin, cyclophosphamide and intrathecal methotrexate administered over 36 days. Patients who achieved complete remission (CR) were randomized to receive consolidation with either the L10M regimen or with DAT (daunomycin, cytosine arabinoside, 6-thioguanine) and escalating MTX and L-asp. The randomization was stratified by age, WBC and Ph chromosome status. Maintenance therapy was the same in both arms. Of 353 eligible patients, 218 (62%) achieved CR and 195 were randomized. The treatment arms did not differ significantly with respect to disease-free survival (DFS; P= 0.46) or overall survival (P= 0.39). Estimated DFS at 5 years was 32% (95% confidence interval (CI) 23-42%) in the L10M arm and 25% (95% CI 16-33%) in the DAT/MTX/L-asp arm. In each arm, 4% of patients died of toxicities (infection in all but one case). Infections and nausea/vomiting were somewhat more common in the L10M arm (occurring in 68% and 53% of patients respectively) than the DAT/MTX/L-asp arm (56% and 33%). The DAT/MTX/L-asp consolidation regimen was associated with some reduction in nonfatal toxicities, but no significant improvement in DFS, overall survival or non-relapse mortality when compared to the standard L10M regimen.

Expression of multiple genes regulating cell cycle and apoptosis in differentiating hematopoietic cells is dependent on iron

OBJECTIVE

Iron plays critical roles in many biological processes including hematopoietic cell growth and differentiation. Iron is essential for the differentiation of HL-60 promonocytes. HL-60 cells stimulated with phorbol myristate acetate (PMA) undergo G1/S phase cell-cycle arrest and differentiate to monocyte/macrophages. With iron deprivation, PMA-induced HL-60 cells bypass differentiation and undergo apoptosis. To investigate the molecular basis underlying this observation, we used commercially available gene microarrays to evaluate expression of multiple genes involved in the regulation of cell cycling and apoptosis.

METHODS

We treated HL-60 cells with PMA +/- desferrioxamine (DF), a potent iron chelator, to produce iron deprivation. Cells were cultured for 48 hours, and cDNA was prepared and radiolabeled with alpha-(32)P dCTP, then hybridized to gene arrays containing specific cDNA fragments.

RESULTS

Expression of 11 of 43 genes was inhibited greater than 50% by iron deprivation. These genes were Rb; p21 (WAF1/CIP1); bad; cdk2; cyclins A, D3, E1; c-myc; egr-1; iNOS; and FasL. For each gene the microarray results were confirmed by RT-PCR and/or Northern or Western blotting. Nuclear transcription assays indicated that the role of iron in Rb expression was to support gene transcription. Addition of ferrioxamine (iron saturated DF) instead of DF to PMA-induced cells did not affect gene expression, indicating that diminished expression was due to iron deprivation, not nonspecific toxicity.

CONCLUSION

Iron supports expression of multiple cell cycle-regulatory and apoptosis-related genes during HL-60 cell differentiation, and, in this way, is involved in regulation of a critical cell decision point-the decision to pursue a differentiation-related or apoptotic pathway.

Rosette formation between human lymphocytes and sheep erythrocytes. Inhibition of rosette formation by specific glycopeptides

Rosette formation with unsensitized sheep erythrocytes is a characteristic of human thymus dependent lymphocytes. Release of glycopeptides from the sheep erythrocyte by trypsin reduces rosette formation. These tryptic glycopeptides inhibit rosette formation by untrypsinized sheep erythrocytes; this suggests that rosetting is mediated by erythrocyte surface glycopeptides. To investigate the molecular nature of this interaction, we examined the abilities of various model compounds to act as haptenic inhibitors of rosette formation. Inhibition is given by glycopeptides bearing oligosaccharide units rich in sialic acid, galactose, N-acetylglucosamine, and mannose linked to asparagine residues through glycosylamine bonds. Among compounds tested, fetuin glycopeptide is most effective, but human transferrin glycopeptide and human erythrocyte glycopeptide I also inhibit rosette formation. Other compounds including human erythrocyte glycopeptide II, human IgG glycopeptide, lacto-N-neotetraose, 3'- and 6'-sialyllactose show no significant inhibition. Neither sialic acid, galactose, manose, nor N-acetyl-glucosamine alone inhibits rosette formation. Stepwise degradation of fetuin glycopeptide established the galactose residues as important determinants of inhibitory activity. Fetuin glycopeptide blocks rosette formation when added to a suspension of human lymphocytes and sheep erythrocytes or when preincubated with human lymphocytes, but not when preincubated with sheep erythrocytes. Studies of the binding of [3H] fetuin glycopeptide to normal lymphocytes demonstrate 7.5 x 10(6) saturable binding sites per cell. No saturable binding of this compound to sheep erythrocyte membranes is observed. Compared to normals, lymphocytes from patients with chronic lymphatic leukemia demonstrate decreased fetuin glycopeptide binding with a mean of 0.9 x 10(6) sites per cell. This decreased binding correlates with the impaired ability of these cells to form rosettes. The data suggest that fetuin glycopeptide inhibits rosette formation by binding to the thymus-dependent cell where competition occurs with sheep erythrocytes for specific lymphocyte surface receptors.

Phase I study of high-dose continuous-infusion recombinant interleukin-2 and autologous lymphokine-activated killer cells in patients with metastatic or unresectable malignant melanoma and renal cell carcinoma

The current study was undertaken to determine the maximum tolerated dose of recombinant interleukin-2 (rIL-2) that could be administered as a continuous infusion in conjunction with autologous lymphokine-activated killer (LAK) cells. All 55 patients in this study received a priming dose of rIL-2 of 1.0 mg/m2 per day given as a continuous infusion over 4.5 days. Patients later received (days 11-16) one of three doses of rIL-2 per day (1.0, 1.25, or 1.50 mg/m2) in conjunction with LAK cells given on days 11, 12, and 14. Because of unacceptable toxicity occurring early in the LAK cell phase of therapy at the rIL-2 dose level of 1.50 mg/m2, we concluded that the maximum tolerated dose of rIL-2 given as a continuous infusion with LAK cells is 1.25 mg/m2 per day.

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.

Phase IB clinical trial of anti-CD3 followed by high-dose bolus interleukin-2 in patients with metastatic melanoma and advanced renal cell carcinoma: clinical and immunologic effects

PURPOSE

To determine the maximum-tolerated dose (MTD) of an anti-CD3 antibody, OKT3, in combination with high-dose interleukin-2 (IL-2), and to determine whether OKT3 can enhance the expansion of CD3+, CD25+ (IL-2 receptor alpha [IL-2R alpha])-expressing T cells in the peripheral blood of patients with advanced melanoma and renal cell carcinoma receiving high-dose IL-2.

PATIENTS AND METHODS

We performed a phase IB trial of a murine monoclonal anti-CD3 antibody (OKT3) with high-dose IL-2 in patients with advanced melanoma and renal cell carcinoma. Fifty-four patients were enrolled, with cohorts of 10 or more patients receiving escalating doses of OKT3 at 75, 200, 400, and 600 micrograms/m2 on day 1 followed by IL-2 at an initial dose 0.45 and then 1.33 mg/m2 every 8 hours on days 2 through 6 and 16 through 20 (maximum, 28 doses). An additional cohort of 14 patients received high-dose IL-2 (1.33 mg/m2 per dose) alone. Circulating CD3+, CD25+ cells were monitored before therapy and following the initial week of IL-2.

RESULTS

A total of 68 patients were enrolled. The MTD for OKT3 was defined as 400 micrograms/m2 based on a reduction in the number of IL-2 doses that could be administered. Increases in CD3+, CD25+ cells were observed within all cohorts; however, the increase was not OKT3 dose-dependent. On the other hand, we found that 60% (nine of 15) of patients tested at OKT3 dose levels of 200, 400, and 600 micrograms/m2 had increases in serum sCD25 (soluble IL-2R alpha) to more than 100,000 U/mL, while none of 10 patients who received IL-2 alone or with OKT3 at the 75-micrograms dose had increases greater than 60,000 U/mL. Of 29 patients with renal cell carcinoma who received OKT3 with IL-2 (1.33 mg/m2), there were three objective tumor responses (all partial responses). In the 16 patients with melanoma who received OKT3 plus IL-2, there was a single objective response (complete response).

CONCLUSION

The doses of OKT3 administered on this schedule failed to enhance significantly the number of circulating CD3+, CD25+ T cells and did not appear to increase the antitumor activity of IL-2 alone, which underscores the need for other approaches to enhance the efficacy of IL-2 therapy.

Phytohemagglutinin-induced diarrheal disease

A purified plant lectin, phytohemagglutinin (PHA), or crude red kidney bean (RKB) from which it was derived, when incorporated as 1% of dietary protein into a purified casein protein diet caused weanling rats to fail to grow or lose weight in comparison to control animals pair fed an isonitrogenous, isocaloric diet. Feeding PHA was observed to cause diarrhea: fecal wet and dry weights were increased within 2 days after starting the diet. Increased fecal weight was caused by increased dry weight as well as by an increased fecal water content. On reversion to a normal casein diet, rapid amelioration of the antinutritional effects of PHA occurred with resumption of normal growth rate. Specific binding of PHA to the microvillus region of the small intestinal epithelium was demonstrated using rabbit anti-PHA and fluorescein-labeled goat anti-rabbit immunoglobin. PHA binding was observed after chronic intake in the diet or when applied to normal tissue in vitro. Loss of PHA binding to the intestine was observed to occur within 48 hr on reversion to a control casein diet. No significant morphological damage to the microvilli or the mucosal villus architecture was observed to accompany PHA adherence under these experimental conditions. Antinutritional and antiabsorptive effects of dietary PHA were associated with diarrhea. PHA adhered to the microvillus membrane of the small intestinal villus surface during the diarrheal state.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding of isolectins from red kidney bean (Phaseolus vulgaris) to purified rat brush-border membranes

Ingestion of red kidney bean phytohemagglutinin causes impaired growth and intestinal malabsorption, and facilitates bacterial colonization in the small intestine of weanling rats. We have studied interactions of the highly purified phytohemagglutinin erythroagglutinating (E4) and mitogenic (L4) isolectins with microvillous membrane vesicles prepared from rat small intestines. E4 and L4 were radioiodinated with 125I by the chloramine-T technique. E4 and L4 isolectins both bound to microvillous membrane vesicles. Binding was saturable and reversible. Each mg of membrane protein bound 744 +/- 86 micrograms E4 and 213 +/- 21 micrograms L4. The apparent Ka for E4 and L4 binding was 2.5 x 10(-6) and 13.0 x 10(-6) M-1, respectively. Binding of each 125I-labelled isolectin was abolished by 100-fold excess of unlabelled isolectin. In each case binding also was inhibited by appropriate oligosaccharide inhibitors, indicating that isolectin-microvillous membrane interactions were mediated by carbohydrate recognition. Patterns of saccharide inhibition of isolectin binding were different for E4 and L4. Competitive binding experiments demonstrated mutual noncompetitive inhibition of E4 and L4 binding consistent with steric hindrance. Therefore, E4 and L4 each bound to its own set of receptors. Based on the known saccharide specificities of E4 and L4, these data indicate that there are differences in expression of complex asparagine-linked biantennary and tri- or tetraantennary oligosaccharides at the microvillous surface. The data also provide the possibility that direct interactions of one or more phytohemagglutinin isolectins with intestinal mucosa in vivo may contribute to the antinutritional effects associated with ingestion of crude red kidney beans.

Phase I clinical and pharmacokinetic trial of flavone acetic acid

Flavone acetic acid is a synthetic benzopyrone derivative with an unknown mechanism of action. Thirty-eight patients (30 men and 8 women) were treated once a week for 4 weeks every 5 weeks with doses of flavone acetic acid ranging from 0.33 to 12.5 g/m2. At doses less than or equal to 3.9 g/m2, the drug was administered intravenously over 1 hour; at doses greater than or equal to 5.28 g/m2, the infusion period was lengthened to 6 hours. Treatment of all patients included hydration before and after treatment and alkalization to maintain urine pH at greater than or equal to 6.5. A dose-limiting toxic effect was hypotension at 10 g/m2. Pharmacokinetic studies revealed linear behavior in the eight patients studied, beginning at 3.9 g/m2. Peak plasma levels ranged from 125 to 630 micrograms/mL, with a mean terminal half-life of 22.4 hours. Immunologic monitoring was performed in three patients at 10 g/m2. A transient increase in CD16- and/or Leu-19-positive cells was noted in all three patients. In one patient, this increase correlated with a 10-fold increase in K562 cell killing. There were no objective tumor responses seen in this trial. The recommended phase II dose on this schedule is 8 g/m2. Further studies to elucidate the drug's mechanism of action and to define its immunologic properties are recommended.

A phase II study of high dose ARA-C and mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia

PURPOSE

The Southwest Oncology Group performed a Phase II study to investigate the effectiveness of an induction regimen of high dose cytosine arabinoside (ara-C) with high dose mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Patients at least 16-years-old with ALL that was in relapse after, or was refractory to, standard induction therapy including at least vincristine and prednisone were eligible, as long as they had no prior treatment with high dose ara-C. The induction regimen included high dose ara-C (3 g/m2 by 3-h i.v. days 1-5) and mitoxantrone (80 mg/m2 by 15-30 min i.v. 12-20 h after the first dose of ara-C). The study design called for a maximum of 55 patients, with early termination if less than nine of the first 30 achieved complete remission.

RESULTS

Thirty-three patients entered the study, and 31 were included in the analysis. All 31 completed one course of induction therapy. Four patients died of infection and a fifth of cardiomyopathy with possible sepsis. Seven patients achieved complete remission (23%; 95% confidence interval 10-41%). One of the seven received syngeneic bone marrow transplantation while in remission, and the other six all relapsed within 10 months. All 31 patients died within 25 months after entering the study.

CONCLUSIONS

The regimen of high dose ara-C and mitoxantrone was found to be insufficiently effective to warrant further investigation.

Phase II trials of high-dose interleukin-2 and lymphokine-activated killer cells in advanced breast carcinoma and carcinoma of the lung, ovary, and pancreas and other tumors

Treatment with interleukin-2 (IL-2) used alone or in combination with lymphokine-activated killer (LAK) cells is known to be an active therapy for patients with advanced renal cell carcinoma and melanoma. To further explore the activity of IL-2/LAK cell therapy in patients with advanced cancer of various primary sites, the Extramural IL-2/LAK Working Group (ILWG) initiated two phase II trials of high-dose IL-2/LAK therapy: one in patients with advanced breast carcinoma, and one in patients with advanced cancer arising in other sites. Patients with advanced renal cell carcinoma, melanoma, colorectal carcinoma, and lymphoma (Hodgkin's and B-cell non-Hodgkin's) were not eligible for the latter trial, but were treated on other ILWG trials that have been reported previously. Sixty-nine patients received high-dose IL-2 (600,000 IU/kg administered by a 15-min intravenous infusion every 8 h) on days 1-5 and days 11-15. Leukapheresis was performed for collection and ex vivo expansion of LAK cells on days 7-10, and the LAK cells were reinfused on days 11, 12, and 14. The studies were designed to determine whether treatment with IL-2/LAK resulted in at least a 40% response rate, a level of activity that was believed to be sufficient to justify the toxicity and cost of IL-2/LAK therapy. An adequate number of patients with carcinoma of the breast (N = 12), pancreas (N = 8), ovary (N = 7), and lung (non-small cell; N = 6) were accrued to assess response; most of these patients had prior chemotherapy that had failed.(ABSTRACT TRUNCATED AT 250 WORDS)