Carbonyl reductase as a significant predictor of survival and lymph node metastasis in epithelial ovarian cancer

We have recently reported a novel function for carbonyl reductase (CR), namely, its ability to modulate the metastatic potential of malignant mouse cells. Because there are currently no data addressing a similar function for CR in human cancers, the aim of this study was to assess a correlation between survival and metastasis, and CR level in epithelial ovarian cancer. Using anti-CR antibody, immunohistochemical staining was performed on 73 epithelial ovarian cancers, 13 borderline malignant tumours, and 25 benign ovarian tumours for a total of 111 specimens. The combined rate for strongly and weakly positive reactions for CR was 32.0% for benign tumours, 38.5% for borderline malignant tumours, and 61.6% for ovarian cancers. The CR-positive rate was 35.7% (weakly positive alone) for ovarian cancers with retroperitoneal lymph node (RLN) metastasis and 67.8% for those without RLN metastasis (P< 0.05). The 5-year survival rate was 62.7% for the patients with CR-negative cancer and 86.1% for those with CR-positive cancer (P< 0.05). The present results indicate that decreased CR expression in epithelial ovarian cancer is associated with RLN metastasis and poor survival.© 2001 Cancer Research Campaignhttp://www.bjcancer.co

Crowding Alone Cannot Account for Cosolute Effect on Amyloid Aggregation

Amyloid fiber formation is a specific form of protein aggregation, often resulting from the misfolding of native proteins. Aimed at modeling the crowded environment of the cell, recent experiments showed a reduction in fibrillation halftimes for amyloid-forming peptides in the presence of cosolutes that are preferentially excluded from proteins and peptides. The effect of excluded cosolutes has previously been attributed to the large volume excluded by such inert cellular solutes, sometimes termed “macromolecular crowding”. Here, we studied a model peptide that can fold to a stable monomeric β-hairpin conformation, but under certain solution conditions aggregates in the form of amyloid fibrils. Using Circular Dichroism spectroscopy (CD), we found that, in the presence of polyols and polyethylene glycols acting as excluded cosolutes, the monomeric β-hairpin conformation was stabilized with respect to the unfolded state. Stabilization free energy was linear with cosolute concentration, and grew with molecular volume, as would also be predicted by crowding models. After initiating the aggregation process with a pH jump, fibrillation in the presence and absence of cosolutes was followed by ThT fluorescence, transmission electron microscopy, and CD spectroscopy. Polyols (glycerol and sorbitol) increased the lag time for fibril formation and elevated the amount of aggregated peptide at equilibrium, in a cosolute size and concentration dependent manner. However, fibrillation rates remained almost unaffected by a wide range of molecular weights of soluble polyethylene glycols. Our results highlight the importance of other forces beyond the excluded volume interactions responsible for crowding that may contribute to the cosolute effects acting on amyloid formation

Pharmacokinetics, pharmacodynamics and metabolism of the dimeric pyrrolobenzodiazepine SJG-136 in rats

The dimeric pyrrolobenzodiazepine SJG-136 (NSC 694501, SG2000) has potent in vitro antiproliferative activity and in vivo antitumor activity associated with binding in the minor groove of DNA and formation of covalent interstrand DNA cross-links. The pharmacokinetics and in vitro metabolism of SJG-136 and as well as the feasibility of using the Comet assay to measure in vivo interstrand DNA cross-links, was assessed in the rat.SJG-136 pharmacokinetics and pharmacodynamics were characterized in rats following single-dose administration of 15 and 50 mu g/kg or multiple-dose administration of 25 mu g/kg/day for 5 days. DNA damage was measured in peripheral blood mononuclear cells using the Comet assay. SJG-136 oxidative metabolism was characterized in rat liver microsomes.SJG-136 half-life, clearance and volume of distribution values were 9 min, 190 ml/min/m(2), and 1780 ml/m(2), respectively. SJG-136 did not accumulate in plasma during treatment with 25 mu g/kg/day for 5 days. Treatment with SJG-136 produced the anticipated DNA interstrand cross-links, as well as DNA strand breaks, in rat PBMCs. Oxidative metabolism of SJG-136 in rat liver microsomes was catalyzed by CYP3A isoforms and produced a previously unreported monomeric metabolite.Plasma concentrations of SJG-136 associated with pharmacological activity and in vitro antiproliferative activity were achieved with doses that were tolerated by rats. CYP3A isoforms are the predominant P450s catalyzing SJG-136 metabolism. The comet assay detects DNA damage in PBMCs from rats treated with SJG-136 and is being used in clinical trials to monitor in vivo lesions produced by SJG-136