Arsenic-induced apoptosis in malignant cells in vitro

Developmental therapeutics in childhood cancer. A perspective from the Children's Oncology Group and the US Food and Drug Administration

Drug development in pediatric oncology has been reviewed, concentrating on overall development issues and COG studies of cytotoxic compounds. A variety of interesting molecules with more specific targeting are becoming available. The challenges that remain include the availability of such compounds for pediatric trial and their study in a timely fashion, and the subsequent incorporation of the new agents into more up-front regimens, with the ultimate shared goal of curing more children with less toxicity.

Chronic Fatigue Syndrome (CFS) in 15 dogs and cats with specific biochemical and microbiological anomalies

A great deal of controversy and speculation surrounds the etiology of Chronic Fatigue Syndrome (CFS) in human patients and the existence of a similar illness in animals. To evaluate the association with a presumptive staphylococcal infection and bacteremia, seven dogs and eight cats diagnosed with CFS (two meeting the CDC working case definition) were submitted to rapid blood cultures and fresh blood smears investigations. Nine out of 15 blood cultures proved Staph-positive and four isolates were specified as S. xilosus (3) and S. intermedius (1). The presence of micrococci-like organisms in the blood was of common observation among these subjects, in association with fatigue/pain-related symptoms and biochemical abnormalities suggestive of a myopathy. Following treatment with a low dosage arsenical drug (thiacetarsamide sodium, Caparsolate, i.v., 0.1 ml/kg/day) all patients experienced complete remission. Micrococci disappeared from the blood at post-treatment controls made 10-30 days later. The outcomes were compared with those of five healthy controls and five 'sick with other illness' patients showing significant difference.

Opposite effect of NF-kappa B and c-Jun N-terminal kinase on p53-independent GADD45 induction by arsenite

Cell cycle checkpoint, a major genomic surveillance mechanism, is an important step in maintaining genomic stability and integrity in response to environmental stresses. Using cells derived from human bronchial epithelial cells, we demonstrate that NF-kappaB and c-Jun N-terminal kinase (JNK) reciprocally regulate arsenic trioxide (arsenite)-induced, p53-independent expression of GADD45 protein, a cell cycle checkpoint protein that arrests cells at the G(2)/M phase transition. Inhibition of NF-kappaB activation by stable expression of a kinase-mutated form of IkappaB kinase caused increased and prolonged induction of GADD45 by arsenite. In contrast, the induction of GADD45 by arsenite was transient and less potent in cells where the NF-kappaB activation pathway was normal. Analysis of the cell cycle profile by flow cytometry indicated that NF-kappaB inhibition potentiates arsenite-induced G(2)/M cell cycle arrest. Abrogation of JNK activation, on the other hand, decreased GADD45 expression induced by arsenite, suggesting a role for JNK activation in GADD45 induction. These results indicate a molecular mechanism by which NF-kappaB and JNK may differentially contribute to cell cycle regulation in response to arsenite.