Granzyme M targets topoisomerase II alpha to trigger cell cycle arrest and caspase-dependent apoptosis

Cytotoxic lymphocyte protease granzyme M (GrM) is a potent inducer of tumor cell death. The apoptotic phenotype and mechanism by which it induces cell death, however, remain poorly understood and controversial. Here, we show that GrM-induced cell death was largely caspase-dependent with various hallmarks of classical apoptosis, coinciding with caspase-independent G2/M cell cycle arrest. Using positional proteomics in human tumor cells, we identified the nuclear enzyme topoisomerase II alpha (topoIIα) as a physiological substrate of GrM. Cleavage of topoIIα by GrM at Leu(1280) separated topoIIα functional domains from the nuclear localization signals, leading to nuclear exit of topoIIα catalytic activity, thereby rendering it nonfunctional. Similar to the apoptotic phenotype of GrM, topoIIα depletion in tumor cells led to cell cycle arrest in G2/M, mitochondrial perturbations, caspase activation, and apoptosis. We conclude that cytotoxic lymphocyte protease GrM targets topoIIα to trigger cell cycle arrest and caspase-dependent apoptosis.

[The development of a treatment program for violent forensic psychiatric patients with a cluster B personality disorder]

BACKGROUND

Very few articles have been published in professional journals concerning the design, content, and results of treatment programs for violent forensic psychiatric patients in the Netherlands.

AIM

To describe the development of a treatment program for forensic psychiatric patients with a cluster B personality disorder. In this program a treatment for aggression was combined with a treatment for substance abuse.

METHOD

Clinical findings obtained with both treatments are discussed, followed by a description of new modules that were added because of recent research results. results The combined treatment program targets the principal dynamic factors that cause individuals to display criminal behaviour.

CONCLUSION

Empirical research is needed in order to find out whether the treatment as a whole produces better results than the two treatments administered separately.

Solid phase microextraction as a tool to predict internal concentrations of soil contaminants in terrestrial organisms after exposure to a laboratory standard soil

Uptake and accumulation of three chlorobenzenes was studied in both biota (Enchytraeus crypticus) and 30 mum polydimethylsiloxane (PDMS) solid phase microextraction (SPME) fibers after exposure to spiked OECD soil. The OECD soil was spiked with three different concentrations of all contaminants. Uptake of all three chlorobenzenes in E. crypticus was fast and steady state levels were reached within 2-4 days. Also in the PDMS-SPME fibers uptake was very fast for all three compounds, with steady state levels reached after 1 day. Comparison of steady state levels in biota and in the PDMS-SPME fibers showed a relationship which was consistent over the range of concentrations of chlorobenzenes in soil and the difference in logKow. This shows that measuring the concentrations of hydrophobic chemicals in a hydrophobic phase such as PDMS can be used as a simple tool to estimate internal concentrations of these chemicals in biota exposed to complex matrices such as soil.

Determination of polycyclic aromatic hydrocarbons (PAH) and their metabolites in blood, feces, and urine of rats orally exposed to PAH contaminated soils

Polycyclic aromatic hydrocarbons (PAH) have become an ubiquitous upper soil component as a consequence of industrialization involving a multitude of combustion processes. Ingestion of PAH contaminated soil is considered to be a major exposure route, specifically for small children living on these soils. Health risk assessment is based on extrapolations from data obtained via studies performed with pure chemicals. Additionally it is assumed that after oral intake all PAH present in the soil will be absorbed by the human body. Interactions with the soil matrix, however, may modulate the bioavailability of PAH. In this study, we examined the absorption and excretion of PAH in rats orally exposed either to industrially contaminated soils or pure model compounds as anthracene, pyrene and benzo(a)pyrene (B[a]P). The model compounds and the metabolites, 1-hydroxypyrene (1-OH-pyrene) and 3-hydroxybenzo(a)pyrene (3-OH-B[a]P), were measured in blood, feces or urine by means of HPLC with fluorescence detection. Because of rapid biotransformation only minimal levels of unmetabolized anthracene, pyrene and B[a]P in blood could be detected. The pharmacokinetic parameters were nonlinear and suggestive of enterohepatic cycling. Only low levels of the compounds were excreted unchanged in feces whereas the levels of the metabolites were considerably higher in feces and urine. These results indicate that the dosed PAH are largely absorbed by the gastrointestinal tract, subsequently metabolized and excreted as metabolites via urine and feces. Significant differences between the soil-treated group and the pure mixture-treated group could be observed; the soil-treated group showed higher fecal excretion of unchanged pyrene (0.5 versus 0.2% of the original dose) and B[a]P (1 versus 0.3%), lower excretion of 1-OH-pyrene in feces (5.1 versus 17. 0%), and lower excretion of 1-OH-pyrene in urine (0.2 versus 3.4%). The fecal excretion of 3-OH-B[a]P between the two groups was similar (8.8 versus 8.8%). These results suggest that the soil matrix is capable of reducing the absorption of at least pyrene. Therefore, exposure risk assessment models assuming complete bioavailability of soilmatrix-bound PAH probably overestimate the endogenous dose.