Citations

PurposeThis multicenter, dose-escalation study evaluates the safety, pharmacokinetics, and efficacy of galiximab (anti-CD80 monoclonal antibody) in patients with relapsed or refractory follicular lymphoma.Patients and MethodsPatients had follicular lymphoma that had relapsed or failed to respond to primary therapy; the majority (90%) presented with stage III or IV disease. Four weekly intravenous infusions of galiximab were administered at doses of 125, 250, 375, or 500 mg/m2.ResultsThirty-seven patients received galiximab treatment and were evaluated for safety; 35 were assessable for response. Antibody infusions were safe and well tolerated with no dose-limiting toxicities. A total of 22 (60%) of 37 patients experienced adverse events related to galiximab. All but one of the events were grade 1 or 2; the most common were fatigue, nausea, and headache. Cytopenias were rare; only one patient experienced anemia and febrile neutropenia, which were unrelated to galiximab and resolved after treatment. No patient developed antigaliximab antibody formation. The mean serum half-life ranged from 13 to 24 days. The overall response rate was 11% (two complete responses and two partial responses). Time to best response was delayed (months 3, 6, 9, and 12). Twelve patients (34%) maintained stable disease. Nearly half of all patients (49%) had a decrease in indicator lesions. Two responders remain on study without progression (22 and 24.4 months).ConclusionThe favorable safety profile of galiximab and evidence of single-agent biologic activity and dose-dependent pharmacokinetics support further evaluation of galiximab as a treatment for follicular lymphoma, possibly in combination with other lymphoma therapies.

ABSTRACT Globoid cell leukodystrophy (GLD) or Krabbe disease is a devastating, degenerative neurological disorder caused by mutations in the galactosylceramidase (GALC) gene that severely affect enzyme activity. Currently, treatment options for this disorder are very limited. Enzyme replacement therapy (ERT) has been shown to be effective in lysosomal storage disorders with predominantly peripheral manifestations such as type I Gaucher's and Fabry's disease. Little however is known about the possible benefit of ERT in GLD, which has a substantial central nervous system component. In this study, we examined the effect of peripheral GALC injections in the twitcher mouse model of the disease. Although we were unable to block the precipitous decline that normally occurs just before death, we did observe significant early improvements in motor performance, a substantial attenuation in the initial failure to thrive, and an increase in life span. Immunohistochemical and activity analyses demonstrated GALC uptake in multiple tissues, including the brain. This was associated with a decrease in the abnormal accumulation of the GALC substrate psychosine, which is thought to play a pivotal role in disease pathology. These results indicate that peripheral ERT is likely to be beneficial in GLD.

Circulating cytokines, hormones, and growth factors control all aspects of cell proliferation, differentiation, angiogenesis, apoptosis, and senescence. These chemical signals are propagated from the cell surface to intracellular processes via sequential kinase signaling, arranged in modules that exhibit redundancy and cross talk. This signal transduction system comprising growth factors, transmembrane receptor proteins, and cytoplasmic secondary messengers is often exploited to optimize tumor growth and metastasis in malignancies. Thus, it represents an attractive target for cancer therapy. This review will summarize current knowledge of selected intracellular signaling networks and their role in cancer therapy. The focus will be on pathways for which inhibitory agents are currently undergoing clinical testing. Original data for inclusion in this review were identified through a MEDLINE search of the literature. All papers from 1966 through March 2005 were identified by the following search terms: “signal transduction,” “intracellular signaling,” “kinases,” “proliferation,” “growth factors,” and “cancer therapy.” All original research and review papers related to the role of intracellular signaling in oncogenesis and therapeutic interventions relating to abnormal cell signaling were identified. This search was supplemented by a manual search of the Proceedings of the Annual Meetings of the American Association for Cancer Research, American Society of Clinical Oncology, and the American Association for Cancer Research (AARC) –European Organisation for Research and Treatment of Cancer (EORTC) –National Cancer Institute (NCI) Symposium on New Anticancer Drugs.

PurposeMantle cell lymphoma (MCL) is characterized by a t(11;14) resulting in overexpression of cyclin D1 messenger RNA. This study tested whether temsirolimus (previously known as CCI-779), an inhibitor of the mammalian target of rapamycin kinase that regulates cyclin D1 translation, could produce tumor responses in patients with MCL.Patients and MethodsPatients with relapsed or refractory MCL were eligible to receive temsirolimus 250 mg intravenously every week as a single agent. Patients with a tumor response after six cycles were eligible to continue drug for a total of 12 cycles or two cycles after complete remission, and were then observed without maintenance.ResultsThirty-five patients were enrolled and were assessable for toxicity; one patient had MCL by histology but was cyclin D1 negative and was ineligible for efficacy. The median age was 70 years (range, 38 to 89 years), 91% were stage 4, and 69% had two or more extranodal sites. Patients had received a median of three prior therapies (range, one to 11), and 54% were refractory to the last treatment. The overall response rate was 38% (13 of 34 patients; 90% CI, 24% to 54%) with one complete response (3%) and 12 partial responses (35%). The median time-to-progression in all patients was 6.5 months (95% CI, 2.9 to 8.3 months), and the duration of response for the 13 responders was 6.9 months (95% CI, 5.2 to 12.4 months). Hematologic toxicities were the most common, with 71% (25 of 35 patients) having grade 3 and 11% (four of 35 patients) having grade 4 toxicities observed. Thrombocytopenia was the most frequent cause of dose reductions but was of short duration, typically resolving within 1 week.ConclusionsSingle-agent temsirolimus has substantial antitumor activity in relapsed MCL. This study demonstrates that agents that selectively target cellular pathways dysregulated in MCL cells can produce therapeutic benefit. Further studies of this agent in MCL and other lymphoid malignancies are warranted.

Background Ca2+ influx is a key component of neuronal intracellular Ca2+ ([Ca2+]i) regulation. The authors hypothesized that volatile anesthetic inhibition of neuronal activity is mediated by inhibition of Ca2+ influx via two major mechanisms: plasma membrane Na+-Ca2+ exchange (NCX) and the novel mechanism of Ca2+ influx triggered by endoplasmic reticulum Ca2+ depletion (store-operated Ca2+ channels [SOCCs]). Methods Differentiated rat pheochromocytoma cells loaded with the Ca2+ indicator fura-2 were Na+-loaded with 0 Ca2+, 145 mm Na+ Tyrode's and 5 microm cyclopiazonic acid plus 10 microm ryanodine (functionally isolating plasma membrane). Influx-mode NCX was rapidly reactivated by 0 Na+ and 2.5 mm Ca2+. The protocol was repeated in the presence of volatile anesthetics (0.5-1.5 minimum alveolar concentration [MAC] halothane, isoflurane, or sevoflurane) or other drugs to characterize NCX. To examine SOCCs, endoplasmic reticulum Ca2+ was depleted by cyclopiazonic acid in 0 extracellular Ca2+, and Ca2+ influx was triggered by rapid reintroduction of extracellular Ca2+. The protocol was repeated in the presence of anesthetics or other drugs to characterize SOCCs. Results Influx via NCX was not inhibited by voltage-gated Ca2+ channel blockers but was sensitive to NCX inhibitors. Halothane and isoflurane (0.5-1.5 MAC) significantly inhibited NCX (P < 0.05; paired comparisons), whereas sevoflurane at less than 1.5 MAC did not inhibit NCX. SOCC-mediated Ca2+ influx was insensitive to a variety of Ca2+ channel blockers but was inhibited by Ni2+. Such influx was sensitive only to halothane at greater than 1 MAC but not isoflurane or sevoflurane. Conclusions These data indicate that volatile anesthetics, especially halothane and isoflurane, interfere with neuronal [Ca2+]i regulation by inhibiting NCX but not SOCC-mediated Ca2+ influx (except high concentrations of halothane).

ABSTRACT Paenibacillus popilliae contains vanF encoding a putative d -Ala: d -lactate ( d -Lac) ligase, VanF, as part of the vanY F Z F H F FX F cluster that is similar in structure to the enterococcal vanA and vanB clusters. Using growth curves, we demonstrated that vancomycin resistance in P. popilliae is inducible. Using degenerate oligonucleotides targeted at bacterial cell wall ligases, we identified a second ligase gene with features of a d -Ala: d -Ala ligase in both P. popilliae and the related, vancomycin-susceptible, Paenibacillus lentimorbus . The 3,380-bp region upstream of vanY F Z F H F FX F in P. popilliae ATCC 14706 was sequenced and found to contain genes encoding a putative two-component regulator, VanR F S F , similar to VanRS but more closely related to a family of two-component regulators linked to VanY-like carboxypeptidases in several glycopeptide-susceptible Bacillus species. This upstream region also included a transposase similar to a transposase found in Bacillus halodurans and, in some strains, a 99-bp insertion of unknown function with 95% nucleotide identity to a portion of the Tn 1546 transposase gene. Analysis of glycopeptide resistance-associated clusters from soil and/or insect-dwelling organisms may provide important clues to the molecular evolution of acquired glycopeptide resistance elements in human pathogens.

Recent experimental studies suggest C-reactive protein (CRP) may be a potential mediator of atherosclerosis and its complications. However, there is growing criticism of in vitro CRP studies that use commercial CRP preparations containing biologically active contaminants. The effects of commercial CRP, dialyzed commercial CRP (dCRP) to remove azide, and sodium azide (NaN 3 ) alone at equivalent concentrations to the undialyzed preparation were tested at varying concentrations on human umbilical vein endothelial cells (HUVEC), circulating endothelial outgrowth cells (EOC), and endothelial progenitor cells (EPC) in vitro. CRP and NaN 3 alone exhibited equivalent concentration-dependent, proapoptotic effects on HUVEC, EOC, and EPC ( P <0.01 versus control), whereas dCRP had no such effect. Similarly, CRP and NaN 3 alone caused equivalent concentration-dependent decreases in migration, proliferation, and matrigel tube formation ( P <0.01 versus control) in EOC and HUVEC, whereas dCRP had absolutely no effect on these biological functions at any of the concentrations used. We conclude that proapoptotic, antiproliferative, antimigratory, and antiangiogenic effects of this commercial CRP preparation on a number of endothelial cell phenotypes in culture may be explained by the presence of sodium azide in this preparation. This study has implications for interpretation of in vitro studies using CRP preparations containing azide at equivalent or higher concentrations.