Spermidine/spermine N1-acetyltranferase modulation by novel folate cycle inhibitors in cisplatin-sensitive and -resistant human ovarian cancer cell lines.

OBJECTIVE: Polyamines have been shown to play a role in the growth and survival of several solid tumors, including ovarian cancer. Intracellular polyamine depletion by the inhibition of biosynthesis enzymes or by the induction of the catabolic pathway leads to antiproliferative effects in many different tumor cell lines. Recent studies showed that the thymidylate synthase inhibitor 5-fluorouracil (5-FU) affects polyamine metabolism in colon carcinoma cells through the induction of the key catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT). METHODS: We therefore examined whether combinations of novel folate cycle inhibitors with quinoxaline structure and drugs that specifically target polyamine metabolism, such as diethylderivatives of norspermine (DENSPM) or spermine (BESpm), have synergistic effect in killing cisplatin-sensitive and drug-resistant daughter human ovarian cell lines. RESULTS: Our results showed that simultaneous drug combination or quinoxaline pre-treatment synergistically increased SSAT expression, depleted polyamines, increased reactive oxygen species production, and produced synergistic tumor cell killing in both cell lines. Of note, this combined therapy increased the chemosensitivity of cisplatin-resistant cells and cross-resistant to the polyamine analogues. On the contrary, some pre-treatment regimens of Spm analogues were antagonistic. CONCLUSIONS: These results show that SSAT plays an important role in novel folate cycle inhibitors effects and suggest that their combination with analogues has potential for development as therapy for ovarian carcinoma based on SSAT modulation.

The effects of Crenotherapy and exercise in peripheral arterial occlusive disease. A comparison with simple exercise training.

BACKGROUND: Conservative therapies for patients affected by Peripheral Arterial Occlusive Disease (PAOD) aim first to correct the risk factors and to slow down the disease progression. Among these, exercise has positive effects on blood flow, muscle metabolism and well demonstrated systemic effects. These include reduction of chronic inflammation markers, improvement of walking mechanics and heart function. Controlled physical training increases the ability to perform the daily activities improving life expectancy of these patients. The aim of this study is to evaluate the effects and the effectiveness of physical training performed in thermal water compared to traditional treadmill walking exercise. METHODS: 98 patients affected by IIb stage PAOD, according to Leriche-Fontaine classification, were enrolled. Patients were randomized into two groups: the first arm carried out an intensive training program under medical supervision (group A); the second one carried out a rehabilitative exercise associated with crenotherapy (group B). The following parameters were detected: Ankle-Brachial pressure index (ABI), actual claudication distance (ACD), maximum walking distance (MWD), flow mediated dilatation (FMD) and the intima-media thickness (IMT). All patients underwent Doppler echocardiography and complete biochemical assay. RESULTS: In both groups, there was a statistically significant improvement of lipidaemia compared to baseline. When compared with each other, the two groups did not show statistically significant differences. There were no significant differences between the two groups regarding echocardiographic findings. Vascular reactivity study showed a statistically significant improvement of FMD after 3 months of exercise in both groups. In crenotherapy group (B) FMD values were significantly higher than the treadmill ones (A). In both groups a statistically significant improvement in ACD was observed CONCLUSIONS: Our experience shows that crenotherapy has similar effects compared to traditional physical training in the treatment of PAOD, being equally well tolerated and safe; it gives an advantage over conventional physical training in terms of ACD and MWD improvement, although not statistically significant, and it is extremely welcome to patients compared to traditional physical training. KEY WORDS: Arterioscleroses, Intermittent Claudicatio, Peripheral Arterial Diseasen, Physical Exercise, Rehabilitation.

Growth hormone- and pressure overload-induced cardiac hypertrophy evoke different responses to ischemia-reperfusion and mechanical stretch.

OBJECTIVE: To compare the molecular, histological, and functional characteristics of growth hormone (GH)- and pressure overload-induced cardiac hypertrophy, and their responses to ischemia-reperfusion and mechanical stretch. DESIGN: Four groups of male Wistar rats were studied: aortic banding (n=24, AB) or sham (n=24, controls) for 10 weeks, and GH treatment (n=24; 3.5mg/kg/day, GH) or placebo (n=24, controls) for 4 weeks. At 13 weeks, the rats were randomly subjected to: (i) assessment of basal left ventricular mRNA expression of sarcoplasmic reticulum calcium-ATPase (SERCA-2), phospholamban (PLB), and Na(+)-Ca(2+) exchanger (NCX) and collagen volume fraction (CVF) (Protocol A, 8 rats in each group); (ii) left ventricular no-flow ischemia with simultaneous evaluation of intracellular Ca(2+) handling and ATP, phosphocreatine (PCr) and inorganic phosphate (Pi) content (Protocol B, 12 rats in each group); or (iii) left ventricular mechanical stretch for 40 min with assessment of tumor necrosis-alpha (TNF-alpha) mRNA (Protocol C, 4 rats in each group). Protocol B and C were carried out in a Langendorff apparatus. RESULTS: In Protocol A, no difference was found as to myocardial mRNA content of Ca(2+) regulating proteins and CVF in GH animals vs controls. In contrast, in the AB group, myocardial mRNA expression of SERCA-2 and PLB was downregulated while that of NCX and CVF were increased vs. controls (p<0.05). In Protocol B, recovery of left ventricular function was significantly decreased in AB vs GH groups and controls and this was associated with 1.6-fold increase in intracellular Ca(2+) overload during reperfusion (p<0.05). Baseline ATP content was similar in the four study groups, whereas PCr and Pi was lower in AB vs GH rats and controls. However, the time courses of high-energy phosphate metabolic changes did not differ during ischemia and reperfusion in the four study groups. In Protocol C, no detectable TNF-alpha mRNA level was found in the left ventricular myocardium of GH treated rats and controls at baseline, while a modest expression was noted in AB animals. Mechanical stretch resulted in de novo myocardial TNF-alpha mRNA expression in GH group and controls, which was dramatically increased in AB animals ( approximately 5-fold above baseline, p<0.001). CONCLUSIONS: The data show that cardiac hypertrophy activated by short-term GH treatment confers cardioprotection compared with pressure overload with regard to molecular and histological characteristics, and responses to ischemia-reperfusion and mechanical stretch.

Differential expression of TNF-alpha, IL-6, and IGF-1 by graded mechanical stress in normal rat myocardium.

An isovolumic normal rat heart Langendorff model was used to examine the effects of moderate (15 mmHg) and severe (35 mmHg) mechanical stretch on the time course (from 0 to 60 min) of myocardial expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and insulin-like growth factor (IGF)-1 and their cognate receptors. After 10 min of moderate stretch, TNF-alpha was de novo expressed, whereas constitutive IL-6 and IGF-1 levels were slightly upregulated; no further changes occurred up to 60 min. In comparison, severe stretch resulted in a higher and progressive increase in TNF-alpha, IL-6, and IGF-1 expression up to 20 min. After 20 min, whereas TNF-alpha expression further increased, IL-6 and IGF-1 levels progressively reduced to values lower than those observed under moderate stretch and in unstretched (5 mmHg) control myocardium (IL-6). Mechanical stretch did not significantly alter the expression of the cognate receptors. Indeed, the TNF-alpha receptor (p55) tended to be progressively upregulated under severe stretch over time. The current data provide the first demonstration that TNF-alpha, IL-6, and IGF-1 ligand-receptor systems are differentially expressed within the normal rat myocardium in response to graded mechanical stretch. Such findings may have potential implications with regard to compensatory hypertrophy and failure.