Abrogation of the radiation-induced G2 checkpoint by the staurosporine derivative UCN-01 is associated with radiosensitisation in a subset of colorectal tumour cell lines

Ionising radiation is commonly used in the treatment of colorectal cancer. Tumour cells with mutant p53 undergo cell cycle arrest at G2/M after ionising radiation and evidence suggests that abrogation of this G2 arrest can lead to a premature, aberrant mitosis, thus enhancing ionising radiation-induced cell killing. The G2 checkpoint inhibitor UCN-01 was thus investigated to determine whether it would abrogate the G2 checkpoint induced by 5 Gy ionising radiation in a range of colorectal tumour cell lines. Data presented show that, at doses that are alone non-toxic to the cells, UCN-01 inhibits the ionising radiation-induced G2 checkpoint in five colorectal tumour cell lines with mutant p53. The ability of UCN-01 to sensitise cells to ionising radiation-induced growth inhibition and apoptosis was also investigated and UCN-01 was found to radiosensitise two out of five cell lines. These results were confirmed by long-term colony forming efficiency studies. These results demonstrate that abrogation of the ionising radiation-induced G2 checkpoint is not necessarily associated with sensitisation to ionising radiation, however, some colorectal tumour cell lines can be radiosensitised by UCN-01. Although the mechanism of radiosensitisation is not clear, this may still be an important treatment strategy

Reducing the use of benzodiazepines and cyclopyrrolones in clinical practice

Objective: Recently, the use of benzodiazepines (BZD) and cyclopyrrolones (CP) has drawn a great deal of attention. About 100,000 patients - approximately 2% of the Danish population - are believed to be addicted to BZD. This article describes a simple and effective method of reducing the use of dependency-producing drugs in clinical practice. Methods: Design: Local rules were implemented according to Danish directive CIR nr 12 13/01/2003 regarding addictive drugs. Prescriptions for BZD and CP were only issued on a monthly basis, and only following personal consultation. This monthly requirement forced the physician as well as the patient to evaluate whether the existing prescription pattern was indicated, or whether a drug-reducing regime should be introduced. The prescription pattern was monitored using the Ordiprax System (Institute for Rational Pharmacotherapy, IRF), which records pharmacy's sales of prescription drugs as prescribed by clinical practices. Two individual clinics in Thyborøn - Harboøre Community, covering some 2300 patients, were surveyed. All patients using BZD or CP were included in this study, with the exception of patients suffering from serious psychiatric or physical disorders. Results: After 15 months, the use of BZD and CP was reduced by 50% and 75%, respectively. The process of changing prescription habits was far easier than expected. A whole group of patients, initially invisible to the physician, was exposed. During the first three months, as few as 4-5 additional consultations for every 1000 patients was required. There was essentially no need for assistance from our usual partners, including psychiatrists, hospitals, specialist units for addictive treatment. Conclusion: We strongly recommend that these simple procedures be incorporated into daily routine when prescribing either a BD or a CP

Solid-state NMR sequential assignments of the amyloid core of Sup35pNM

International audienceSup35pNM represents the N-terminal and middle (M) domains of the yeast Saccharomyces cerevisiae prion Sup35p. This fragment is commonly used for structural and functional studies of Sup35p. We here present a solid-state NMR study of fibrils formed by this fragment and show that sequential assignments can be obtained for the rigid and well-ordered parts of the protein using 3D spectroscopy. We describe in detail the sequential assignment of the 22 residues yielding strong, narrow signals with chemical shifts that correspond mostly to β-sheet secondary-structured amino acids that form the fibril core

Modulation of the colon cancer cell phenotype by pro-inflammatory macrophages: A preclinical model of surgery-associated inflammation and tumor recurrence

Peritoneal infection after colorectal cancer surgery is associated with a higher rate of tumor relapse. We have recently proposed that soluble inflammatory factors released in response to a postoperative infection enhance tumor progression features in residual tumor cells. In an effort to set up models to study the mechanisms of residual tumor cell activation during surgery-associated inflammation, we have analyzed the phenotypic response of colon cancer cell lines to the paracrine effects of THP-1 and U937 differentiated human macrophages, which release an inflammatory medium characteristic of an innate immune response. The exposure of the colon cancer cell lines HT-29 and SW620 to conditioned media isolated from differentiated THP-1 and U937 macrophages induced a mesenchymal-like phenotypic shift, involving the activation of in vitro invasiveness. The inflammatory media activated the β-catenin/TCF4 transcriptional pathway and induced the expression of several mesenchymal (e.g., FN1 and VIM) and TCF4 target genes (e.g., MMP7, PTGS2, MET, and CCD1). Similarly, differential expression of some transcription factors involved in epithelial-to-mesenchymal transitions (i.e. ZEB1, SNAI1, and SNAI2) was variably observed in the colon cancer cell lines when exposed to the inflammatory media. THP-1 and U937 macrophages, which displayed characteristics of M1 differentiation, overexpressed some cytokines previously shown to be induced in colorectal cancer patients with increased rates of tumor recurrence associated with postoperative peritoneal infections, thus suggesting their pro-tumoral character. Therefore, the environment created by inflammatory M1 macrophages enhances features of epithelial-to-mesenchymal transition, and may be useful as a model to characterize pro-inflammatory cytokines as putative biomarkers of tumor recurrence risk