Immunophenotype predicts radiation resistance in T-lineage acute lymphoblastic leukemia and T-lineage non-Hodgkin's lymphoma.

In the preclinical arm of our study, the radiobiologic features of primary malignant cells from newly diagnosed and relapsed T-lineage acute lymphoblastic leukemia/non-Hodgkin's lymphoma patients were analyzed using clonogenic assays. A marked heterogeneity existed relative to the intrinsic radiation sensitivity of clonogenic T-lineage ALL/NHL cells from 42 patients. The mean SF2 (surviving fraction at 200 cGy) and alpha values (initial slope of the survival curve) were 0.36 +/- 0.04, and 0.558 +/- 0.079 Gy-1. Fourteen cases had SF2 values of > or = 0.50 and alpha values of < or = 0.2 Gy-1, consistent with a marked intrinsic radiation resistance at the level of clonogenic leukemia/lymphoma cells. Of these 14 radiation resistant cases, 12 were CD3+. Furthermore, the SF2 and D0 values of the 28 CD3+ cases were significantly higher than the SF2 and D0 values of the 14 CD3- cases (SF2: 0.441 +/- 0.048 versus 0.189 +/- 0.045, p = 0.002; D0: 189.6 +/- 26.3 cGy versus 108.7 +/- 18.2 cGy, p = 0.047) and CD3+ cases had smaller alpha values than CD3- cases (0.454 +/- 0.087 versus 0.765 +/- 0.152, p = 0.06). Thus, clonogenic cells from CD3+ T-lineage ALL/NHL patients were more resistant to radiation than clonogenic cells from CD3- T-lineage ALL/NHL patients. In the clinical arm of our study, 33 T-lineage ALL/NHL patients received autologous bone marrow transplants during remission. Pretransplant conditioning consisted of total body irradiation combined with high dose chemotherapy. The expression of CD3 antigen predicted the outcome of relapsed T-lineage ALL/NHL patients undergoing autologous bone marrow transplantation following total body irradiation plus high dose chemotherapy. Overall, the Kaplan-Meier estimate and standard error of the probability of remaining in remission at 3.5 years was 11 +/- 9% with a median relapse-free interval of 102 days. The disease-free survival at 3.5 years was 8 +/- 7% with a median disease-free survival time of 96 days. Notably, the expression of CD3 antigen on T-lineage ALL/NHL cells correlated with the probability of relapse after bone marrow transplantation. While 16 of 19 CD3+ patients relapsed after bone marrow transplantation, only 3 of 8 CD3- patients relapsed. The Kaplan-Meier estimates and standard errors of the probability of remaining in remission at 1 year after bone marrow transplantation were 7 +/- 6% (median relapse-free interval = 74 days) for CD3+ patients (n = 19) and 63 +/- 17% for CD3- patients (n = 8) (p = 0.006).(ABSTRACT TRUNCATED AT 400 WORDS)     

Spermicidal activity of chelated complexes of bis(cyclopentadienyl)vanadium(IV)

Transition metal complexes containing vanadium IV have been shown to modulate the cellular redox potential and catalyse the generation of reactive oxygen intermediates (ROI). Since sperm function is exquisitely susceptible to ROI, we examined the effects of stable chelate complexes of vanadocenes on human sperm motility. We synthesized seven structurally distinct chelate complexes of bis(cyclopentadienyl)vanadium(IV) with bidentate ligands [i.e. vanadocene acetylacetonato monotriflate (VDacac), vanadocene hexafluoro acetylacetonato monotriflate (VDHfacac), vanadocene N-phenyl benzohydroxamato monotriflate (VDPH), vanadocene acethydroxamato monotriflate (VDH), vanadocene catecholate (VDCAT), vanadocene bipyridino ditriflate (VDBPY), and vanadocene dithiocarbamate monotriflate (VDDTC)], and evaluated their spermicidal activity using computer-assisted sperm analysis (CASA; Hamilton-Thorne). All seven chelate complexes of vanadocene elicited potent spermicidal activity at micromolar concentrations (EC50 values: 3.9-106 microM) without affecting the sperm acrosome integrity. The catecholate and acetylacetonate complexes of vanadocene were the most active and the bipyridyl complex the least active with an order of efficacy VDCAT > VDacac > VDDTC > VDPH > VDH > VDHfacac > VDBPY. The spermicidal activity of chelate complexes of vanadocenes was rapid and irreversible since the treated spermatozoa underwent apoptosis, as determined by the flow cytometric analysis of mitochondrial membrane potential, surface annexin V binding assay, in-situ nick-end labelling of sperm nuclei, and confocal laser scanning microscopy. These results provide unprecedented evidence that chelate complexes of vanadocene with bidentate ligands have spermicidal and apoptosis inducing properties. These vanadocene complexes, especially VDacac, may be useful as contraceptive agents.      

Deletion of 7p or monosomy 7 in pediatric acute lymphoblastic leukemia is an adverse prognostic factor: a report from the Children's Cancer Group.

Monosomy 7 or deletions of 7q are associated with many myeloid disorders; however, the significance of such abnormalities in childhood acute lymphoblastic leukemia (ALL) is unknown. Among 1880 children with ALL, 75 (4%) had losses involving chromosome 7, 16 (21%) with monosomy 7, 41 (55%) with losses of 7p (del(7p)), 16 (21%) with losses of 7q (del(7q)), and two (3%) with losses involving both arms. Patients with losses involving chromosome 7 were more likely to be > or =10 years old, National Cancer Institute (NCI) poor risk, and hypodiploid than patients lacking this abnormality. Patients with or without these abnormalities had similar early response to induction therapy. Event-free survival (EFS) and survival for patients with monosomy 7 (P<0.0001 and P=0.0007, respectively) or del(7p) (P<0.0001 and P=0.0001, respectively), but not of patients with del(7q), were significantly worse than those of patients lacking these abnormalities. The poorer EFS was maintained after adjustment for a Philadelphia (Ph) chromosome, NCI risk status, ploidy, or an abnormal 9p. However, the impact on survival was not maintained for monosomy 7 after adjustment for a Ph. These results indicate that the critical region of loss of chromosome 7 in pediatric ALL may be on the p-arm.     

Large Scale Manufacturing of B43(Anti-CD19)-Genistein for Clinical Trials in Leukemia and Lymphoma

We have conjugated the murine monoclonal anti-CD 19 antibody B43 to the tyrosine kinase inhibitor genistein to construct an effective immunoconjugate against CD 19 antigen positive hematologic malignancies. The scaled-up production and purification of B43 antibody, genistein, and B43-Genistein immunoconjugate permitted the manufacturing of a highly purified clinical-grade B43-Genistein preparation. In clonogenic assays, B43-Genistein elicited selective and potent cytotoxicity against CD 19 antigen positive human leukemia cells. To our knowledge, this work represents the first effort of producing a clinical-grade genistein immunoconjugate for treatment of B-lineage leukemia and lymphoma.     

Biotherapy for xenografted human central nervous system leukemia in mice with severe combined immunodeficiency using B43 (anti-CD19)- pokeweed antiviral protein immunotoxin

The study of central nervous system (CNS) leukemia has been hampered by the lack of a suitable animal model. We report that severe combined immunodeficiency (SCID) mice invariably develop rapidly progressive fatal CNS leukemia within 3 weeks after intravenous injection of NALM-6 pre-B acute lymphoblastic leukemia (ALL) cells. Colonization of the dura mater and subarachnoid space, usually of the distal spinal cord with occasional extension into the Virchow-Robin spaces of blood vessels subjacent to the meninges, followed involvement of bone marrow in the skull, vertebrae, and, occasionally, the appendicular skeleton. Occult CNS leukemia was detectable by polymerase chain reaction amplification of human DNA as early as 8 days postinoculation of leukemia cells. We used this in vivo model of human CNS leukemia to examine the therapeutic efficacy and toxicity of intrathecally administered B43 (anti-CD19)-pokeweed antiviral protein (PAP), an anti- B-lineage ALL immunotoxin directed against the pan-B-cell antigen CD19/Bp95. Intrathecal therapy with B43 (anti-CD19)-PAP immunotoxin at nontoxic dose levels significantly improved survival of SCID mice and was superior to intrathecal methotrexate therapy.     

Targeting Janus kinase 3 to attenuate the severity of acute graft-versus-host disease across the major histocompatibility barrier in mice

To prevent the development of acute graft-versus-host disease (GVHD) in lethally irradiated C57BL/6 (H-2b) recipient mice transplanted with bone marrow-splenocyte grafts from major histocompatibility complex (MHC) disparate BALB/c mice (H-2d), recipient mice were treated with the rationally designed JAK3 inhibitor WHI-P131 [4-(4'-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline] (20 mg/kg, 3 times a day [tid]) daily from the day of bone marrow transplantation (BMT) until the end of the 85-day observation period. Total body irradiation (TBI)-conditioned, vehicle-treated control C57BL/6 mice (n = 38) receiving bone marrow-splenocyte grafts from BALB/c mice survived acute TBI toxicity, but they all developed histologically confirmed severe multi-organ GVHD and died after a median survival time of 37 days. WHI-P131 treatment (20 mg/kg intraperitoneally, tid) prolonged the median survival time of the BMT recipients to 56 days. The probability of survival at 2 months after BMT was 11% +/- 5% for vehicle-treated control mice (n = 38) and 41% +/- 9% for mice treated with WHI-P131 (n = 32) (P <.0001). Notably, the combination regimen WHI-P131 plus the standard anti-GVHD drug methotrexate (MTX) (10 mg/m2 per day) was more effective than WHI-P131 or MTX alone. More than half the C57BL/6 recipients receiving this most effective GVHD prophylaxis remained alive and healthy throughout the 85-day observation period, with a cumulative survival probability of 70% +/- 10%. Taken together, these results indicate that targeting JAK3 in alloreactive donor lymphocytes with a chemical inhibitor such as WHI-P131 may attenuate the severity of GVHD after BMT.     

Autologous bone marrow transplantation in high-risk remission T-lineage acute lymphoblastic leukemia using immunotoxins plus 4-hydroperoxycyclophosphamide for marrow purging

Fourteen patients with high-risk T-lineage acute lymphoblastic leukemia (ALL) in complete remission underwent autologous bone marrow transplantation (BMT) in an attempt to eradicate their residual disease burden. A combined immunochemotherapy protocol using a cocktail of two immunotoxins directed against CD5/Tp67 and CD7/Tp41 T-lineage differentiation antigens in combination with the in vitro active cyclophosphamide congener 4-hydroperoxy-cyclophosphamide (4-HC) was used to purge autografts. Despite high dose pretransplant radiochemotherapy and effective purging of autografts, 9 of 14 patients relapsed at a median of 2.5 months (range, 1.2 to 16.8 months) post BMT. Two patients remain alive and disease free at 26 and 28 months post BMT. We used a novel quantitative minimal residual disease (MRD) detection assay, which combines fluorescence activated multiparameter flow cytometry and cell sorting with leukemic progenitor cell (LPC) assays, to analyze remission bone marrow (BM) samples from T-lineage ALL patients for the presence of residual LPCs. Notably, high numbers of residual LPC detected in remission BM before BMT constituted a poor prognostic indicator, providing the first evidence for the biologic significance and clinical value of in vitro T-lineage ALL LPC assays. The median value for the residual leukemia burden before BMT, was approximately 8.6 x 10(3) LPC/10(8) mononuclear cells (MNC) (approximately 0.0086% LPC). Patients with a residual leukemia burden less than this median value appeared to have a better outlook for remaining free of relapse after autologous BMT than patients with a greater leukemia burden (53 +/- 25% v 14 +/- 13%, P = .006, Mantel-Cox). By comparison, the log kill efficacy of purging, the remaining numbers of LPC in purged autografts, or the estimated numbers of reinfused LPC, did not correlate with the probability of disease-free survival (DFS). These results indicate that the primary reason for the recurrence of leukemia was inefficient pretransplant radiochemotherapy rather than inefficient purging of autografts.