A nonpeptidyl mimic of superoxide dismutase, M40403, inhibits dose-limiting hypotension associated with interleukin-2 and increases its antitumor effects

Phase II study of autologous transplantation with interleukin-2-incubated peripheral blood stem cells and posttransplantation interleukin-2 in relapsed or refractory non-Hodgkin lymphoma

Previous work suggested that interleukin (IL)-2 can be used for eradicating residual disease in autologous grafts and for preventing recurrence. We report a phase II study of autologous peripheral blood stem cell transplantation with in vitro IL-2 incubation of peripheral blood stem cells and posttransplantation IL-2 in patients with recurrent or refractory non-Hodgkin lymphoma. Salvage chemotherapy consisted of ifosfamide and etoposide. Responding patients underwent autologous peripheral blood stem cell transplantation. IL-2-incubated stem cells were infused on day 0. IL-2 1 mIU/m2 was given from day 1 until day 28. Four monthly maintenance cycles of IL-2 4 mIU/m2 subcutaneously twice daily days 1 to 5 and days 8 to 11 were administered thereafter. Eighty-four evaluable patients were enrolled, and 60 proceeded to transplantation, of which 56 received IL-2-incubated stem cells. The average received dose of posttransplantation IL-2 was 30% to 50% of planned. Only 42 patients received maintenance IL-2. The average received maintenance dose of IL-2 was also approximately 30% of planned. Most dose reductions were due to toxicity or patient refusal. Three-year survival and progression-free survival for all registered patients were 43% (95% confidence interval [CI], 33%-53%) and 31% (95% CI, 21%-41%), respectively. For the 60 patients undergoing transplantation, they were 59% (95% CI, 46%-72%) and 44% (95% CI, 31%-57%), respectively. There was no relation between the dose of IL-2 received and outcome. Survival and disease-free survival of the study group were similar to those of a previous study cohort that received unmanipulated stem cells and no systemic IL-2. Administration of IL-2-incubated peripheral blood stem cells and intensive posttransplantation IL-2 was associated with considerable but rapidly reversible toxicity. No effect on long-term outcome was observed.

Environmental, pharmacological, and genetic modulation of the HD phenotype in transgenic mice

The HD-N171-82Q (line 81) mouse model of Huntington's disease (HD), expresses an N-terminal fragment of mutant huntingtin (htt), loses motor function, displays HD-related pathological features, and dies prematurely. In the present study, we compare the efficacy with which environmental, pharmacological, and genetic interventions ameliorate these abnormalities. As previously reported for the R6/2 mouse model of HD, housing mice in enriched environments improved the motor skills of N171-82Q mice. However, life expectancy was not prolonged. Significant improvements in motor function, without prolonging survival, were also observed in N171-82Q mice treated with Coenzyme Q10 (CoQ10, an energy metabolism enhancer). Several compounds were not effective in either improving motor skills or prolonging life, including Remacemide (a glutamate antagonist), Celecoxib (a COX-2 inhibitor), and Chlorpromazine (a prion inhibitor); Celecoxib dramatically shortened life expectancy. We also tested whether raising cellular antioxidant capacity by co-expressing high levels of wild-type human Cu/Zn superoxide dismutase 1 (SOD1) was beneficial. However, no improvement in motor performance or life expectancy was observed. Although we would argue that positive outcomes in mice carry far greater weight than negative outcomes, we suggest that caution may be warranted in testing Celecoxib in HD patients. The positive outcomes achieved by CoQ10 therapy and environmental stimuli point toward two potentially therapeutic approaches that should be readily accessible to HD patients and at-risk family members.

Oxygen radical-induced natural killer cell dysfunction: role of myeloperoxidase and regulation by serotonin

Natural killer (NK) cells are functionally suppressed and induced to apoptosis by reactive oxygen species (ROS) produced by mononuclear phagocytes (MPs). These inhibitory events are reversed by the biogenic amine serotonin. MPs generate hydrogen peroxide (H(2)O(2)), which is processed further by myeloperoxidase (MPO) to even more toxic compounds. Earlier studies suggest that serotonin scavenges MP-derived oxygen radicals generated by the MPO-H(2)O(2) system. These findings led us to explore the capability of MPO-deficient MPs to induce NK cell dysfunction. We show that MPs recovered from subjects with MPO deficiency trigger inhibition of NK cells. In addition, MPs recovered from healthy subjects conveyed suppression of NK cells in the presence of the MPO inhibitor ceruloplasmin. We conclude that ROS-dependent inhibition of NK cell function is unrestricted by the availability of MPO-derived oxygen radicals and that the protecting properties of serotonin may operate in the absence of functional MPO. Our data suggest a complex mechanism of MP-induced NK cell inhibition, which comprises the generation of interchangeable oxygen radicals.

Histamine inhibits neutrophil NADPH oxidase activity triggered by the lipoxin A4 receptor-specific peptide agonist Trp-Lys-Tyr-Met-Val-Met

The vasoactive amine histamine is found at high concentrations in the immune and inflammatory tissues. Earlier studies have revealed that histamine regulates the nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase-dependent formation of oxygen radicals by phagocytic cells. However, the effects of histamine on intracellular signal transduction mechanisms of relevance to oxidase regulation remain controversial. For this study, we investigated the effects of histamine on NADPH oxidase activity in human neutrophil granulocytes triggered by a lipoxin A4 receptor agonist [the hexapeptide Trp-Lys-Tyr-Met-Val-Met (WKYMVM), a formyl peptide receptor (FPR) agonist (the chemotactic tripeptide formylmethionyl-leucyl-phenylalanine (fMLF)) and an activator of protein kinase C (phorbol myristate acetate (PMA)]. We report that histamine, acting via H2-type histamine receptors (H2R), suppresses NADPH oxidase-dependent formation of oxygen radicals induced by WKYMVM and fMLF but not that induced by PMA. Peptide-induced mobilization of granule-localized complement receptor 3 (CR3) was unaffected by histamine suggesting that the inhibition specifically affected NADPH oxidase activation. Our data suggest that histamine downregulates FPRL1- and FPR-induced NADPH oxidase activity upstream of protein kinase C (PKC) and downstream of the separation of the peptide-induced signal into granule secretion and oxidase activation.