Enhanced antitumour efficacy of gimatecan in combination with Bcl-2 antisense oligonucleotide in human melanoma xenografts

The anti-apoptotic protein Bcl-2 has been implicated in the intrinsic resistance of melanoma to chemotherapy. The aim of this study was to investigate the effects of anti-Bcl-2 oligonucleotide oblimersen on the antitumour activity of gimatecan, a novel lipophilic camptothecin currently undergoing clinical phase II studies. Results showed a reduced sensitivity of melanoma cells to gimatecan following Bcl-2 transfection and inversely, increased cell sensitivity to gimatecan in combination with oblimersen. In in vivo studies performed in two melanoma xenografts expressing different Bcl-2 levels, the antitumour activity of oblimersen itself was modest, but the combination with gimatecan produced a significant therapeutic advantage. The combination therapy inhibited tumour growth and delayed regrowth of the two tumours tested. The enhancement of antitumour activity was observed at doses that were tolerated well. The effects of oblimersen on antitumour activity and toxicity of gimatecan were dose-dependent. The capability of oblimersen to improve the efficacy of gimatecan supports the therapeutic potential of the drug combination in the treatment of human melanoma.     

Update: current management issues in malignant melanoma

The incidence of melanoma has increased continuously during the last decade. Surgery is the mainstay of therapy but, for patients with thick lesions or regional metastatic lymph nodes, there is a high risk of relapse. For this group of patients, there is no standard therapy or general agreement amongst oncologists. In this article, we review the current management of melanoma with regard to past completed adjuvant trials and open trials. Moreover, we discuss the role of chemotherapy in metastatic melanoma, in particular with attention to the use of fotemustine.     

Tenascin C and epidermal growth factor receptor as markers of circulating tumoral cells in bladder and colon cancer

Tenascin C has been recently suggested as a tumor marker, however, its levels in serum has been evaluated only in patients with head and neck cancer and melanoma. In this study, we investigated Tenascin C expression in blood samples from colorectal and bladder cancer patients, compared to that of epidermal growth factor receptor (EGFR), a known circulating tumor marker in these cancer types. RT-PCR specific for Tenascin C and EGFR was performed on RNAs extracted from blood samples of 60 patients affected by colon or bladder cancer. We then investigated the statistical association between Tenascin C, EGFR expression and disease-free survival using the Kaplan-Meier method. Furthermore, in order to select which variable between EGFR and Tenascin C was the most predictive for recurrence, a Cox model for proportional risk was applied. Among all patients analysed, a significantly higher disease-free time was found in the group negative for both EGFR and Tenascin C expression; EGFR expression was significantly correlated to disease progression in stages III and IV, whereas in all patients with stage I and II disease Tenascin C correlated better with prognosis. Negative expression of both EGFR and Tenascin C identifies a group of patients with poor tendency to disease recurrence and longer relapse-free time. While Tenascin C expression seems to influence prognosis in patients with low-stage disease, EGFR appears a marker of worse prognosis in patients with high-staged tumors.     

Update on the Cytogenetics and Molecular Genetics of Chordoma

Chordoma is a rare mesenchymal tumour of complex biology for which only histologic and immunohistochemical criteria have been defined, but no biomarkers predicting the clinical outcome and response to treatment have yet been recognised. We herein review the interdisciplinary information achieved by epidemiologists, neurosurgeons and basic scientists on chordoma, usually a sporadic tumour, which also includes a small fraction of familial cases. Main focus is on the current knowledge of the genetic alterations which might pinpoint candidate genes and molecular mechanisms shared by sporadic and familiar chordomas. Due to the scarcity of the investigated tumour specimens and the multiple chromosome abnormalities found in tumours with aberrant karyotypes, conventional cytogenetics and Fluorescence In Situ Hybridization failed to detect recurrent chordoma-specific chromosomal rearrangements. Genome-wide approaches such as Comparative Genomic Hybridization (CGH) are yet at an initial stage of application and should be implemented using BAC arrays either genome-wide or targeting selected genomic regions, disclosed by Loss of Heterozygosity (LOH) studies. An LOH region was shown by a systematic study on a consistent number of chordomas to encompass 1p36, a genomic interval where a candidate gene was suggested to reside. Despite the rarity of multiplex families with chordoma impaired linkage studies, a chordoma locus could be mapped to chromosome 7q33 by positive lod score in three independent families. The role in chordomagenesis of the Tuberous Sclerosis Complex (TSC) genes has been proved, but the extent of involvement of TSC1 and TSC2 oncosuppressors in chordoma remains to be assessed. In spite of the scarce knowledge on the genetics and molecular biology of chordoma, recent initiation of clinical trials using molecular-targeted therapy, should validate new molecular targets and predict the efficacy of a given therapy. Comparative genetic and biomolecular studies should enhance the molecular taxonomy of chordoma which might have a prognostic significance and better orient the therapeutic options.     

Sedation in PACU: the role of propofol

In critically ill patients, adequate sedation increases comfort, minimizes stress response and facilitates diagnostic and therapeutic procedures. Propofol (2-, 6-diisopropylphenol) is an intravenous sedative-hypnotic agent popular for sedation in the Intensive Care Unit. The favorable propofol pharmacokinetic, characterized by a three compartment linear model, allows rapid onset and short duration of action. The emergence time from sedation with propofol varies with the depth and the duration of sedation and the patient's bodyweight. Propofol causes hypotension, particularly in volume depleted patients, decreases cerebral oxygen consumption, reduces intracranial pressure and has potent anti-convulsant properties. It is a potent antioxidant, has anti-inflammatory properties and is a bronchodilator. As a consequence of these properties, propofol is being increasingly used in the management of traumatic head injury, status epilepticus, delirium tremens, status asthmaticus and in septic patients. Prolonged use (>48 h) of high doses of propofol (>66 mcg/Kg/min) has been associated with lactic acidosis, bradycardia, and lipidemia in pediatric patients. A rare complication firstly reported in pediatrics patients and also observed in adults is known as "propofol syndrome" characterized by myocardial failure, metabolic acidosis and rhabdomiolysis. Hyperkalemia and renal failure have also been associated with this syndrome. Hypertriglyceridemia and pancreatitis are uncommon complications. A large number of trials have compared the use of propofol with midazolam. Sedation with propofol is associated with adequate sedation in ICU patients, shorter weaning time and earlier tracheal extubation compared to midazolam, but not before ICU discharge.     

New sesquiterpene lactones from Laurus nobilis leaves as inhibitors of nitric oxide production

Two new metabolites 5alphaH,7alphaH-eudesman-4alpha,6alpha,11,12-tetraol (1) and 1beta,15-dihydroxy-5alphaH,7alphaH-eudesma-3,11(13)-dien-12,6alpha-olide ( 2) have been isolated from the methanolic extract of Laurus nobilis L. leaves. Their structures were determined through analysis of their one- and two-dimensional NMR spectral data ((1)H- and (13)C-NMR, DEPT, COSY, HMQC, HMBC and ROESY). The relative stereochemistry is proposed on the basis of combined J-based configuration analysis and ROESY data. In addition, three known sesquiterpene lactones santamarine (3), reynosin (4) and costunolide (5) along with blumenol C (6) were isolated and identified by spectral means. The isolated compounds 1 - 6 were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophages. The most active compound 2 potently inhibited NO (2)(-) release with an IC (50) value of 0.8 microM.     

Mechanism of the anti-inflammatory effect of thiazolidinediones: relationship with the glucocorticoid pathway

The glucocorticoid receptor (GR) and peroxisome proliferator-activated receptors (PPARs) play important roles in both physiological and pathological conditions such as cell differentiation, lipolysis, control of glucose metabolism, immunity, and inflammation. In fact, recent studies suggest that the thiazolidinedione (TZD) class of PPAR-gamma ligands, like glucocorticoids, may also be clinically beneficial in several inflammatory diseases, even if the molecular mechanisms responsible for these activities have not yet been clarified. In this study, by using a murine model of inflammation, the carrageenin-induced paw edema in mouse, we show that the anti-inflammatory activity exhibited by the PPAR-gamma agonists rosiglitazone and ciglitazone is reversed by the GR antagonist RU486 (17 beta-hydroxy-11 beta-[4-dimethylamino phenyl]-17 alpha-[1-propynyl]estra-4,9-dien-3-one). Moreover, by using a conditional GR null cell line, we demonstrate, for the first time to our knowledge, that one of the possible mechanisms explaining the anti-inflammatory activity of TZDs is their ability to activate GR nuclear translocation. In addition, by using J774 cell line lacking PPAR-gamma, we demonstrate that PPAR-gamma expression could not be essential for TZD-mediated GR nuclear translocation, thus explaining, at least in part, the molecular mechanism underlying their anti-inflammatory activity.