Silencing of the polyamine catabolic key enzyme SSAT prevents CDK inhibitor-induced apoptosis in Caco-2 colon cancer cells.

Roscovitine and purvalanol are purine derivative cyclin-dependent kinase (CDK) inhibitors that induce apoptosis in various types of cancer cells. However, their impact on the apoptotic cell death mechanism requires further elucidation. Natural polyamines putrescine, spermidine and spermine play essential roles in the regulation of cell growth and proliferation. Increased levels of polyamines in cells are considered to be involved in cancer progression. Intracellular polyamine levels are under the control of several catabolic enzymes, such as spermidine/spermine-N-acetyl transferase (SSAT), acetylpolyamine oxidase (APAO) and spermine oxidase (SMO), which could be altered by several therapeutic drugs. However, the possible role of polyamines in drug-induced apoptosis has yet to be clarified. In the present study, our aim was to determine the modulation of the polyamine catabolic pathway related to CDK inhibitor-induced apoptosis in Caco-2 cells. We found that roscovitine and purvalanol (each 20 µM) induced apoptosis by activating caspase-9 and -3, and inhibiting the mitochondrial membrane potential in Caco-2 cells. CDK inhibitors decreased the intracellular putrescine and spermine levels without affecting spermidine levels. Although both roscovitine and purvalanol induced SSAT expression, they did not exert a significant effect on the APAO expression profile. SSAT transient silencing prevented roscovitine-induced apoptosis compared to parental cells. Thus, we concluded that roscovitine and purvalanol significantly induce apoptosis in Caco-2 cells by modulating the polyamine catabolism, and that SSAT could be an important target in evaluating the potential role of polyamines in apoptotic cell death.

Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine.

Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine, [seliciclib, 2-(1-ethyl-2-hydroxy-ethylamino)-6-benzylamino-9-isopropylpurine], a promising drug candidate in cancer therapy, has been performed for the first time. The aim of this study was to investigate modulations in colon cancer cells induced by roscovitine. Raman spectra of the cultured HCT116 colon cancer cells treated with roscovitine at different concentrations (0, 5, 10, 25 and 50 µM) were recorded in the range 400-1850 cm(-1). It was shown that the second derivative profile of the experimental spectrum gives valuable information about the wavenumbers and band widths of the vibrational modes of cell components, and it eliminates the appearance of false peaks arising from incorrect baseline corrections. In samples containing roscovitine, significant spectral changes were observed in the intensities of characteristic protein and DNA bands, which indicate roscovitine-induced apoptosis. Roscovitine-induced apoptosis was also assessed by flow cytometry analysis, and analysis of propidium iodide staining. We observed some modifications in amide I and III bands, which arise from alterations in the secondary structure of cell proteins caused by the presence of roscovitine.

Manganese superoxide dismutase polymorphism in chronic pelvic pain syndrome patients.

Chronic pelvic pain syndrome (CPPS) is a common and serious health problem affecting the quality of life in men. In this study, we aim to investigate the manganese superoxide dismutase (MnSOD) polymorphism at nucleotide 47 as a result of the change of Ala to Val on the protein sequence in CPPS patients. The frequencies were 0.45 and 0.38 for the Ala and 0.55 and 0.62 for Val in National Institutes of Health category 3a and 3b groups. The differences between control and CPPS patients were statistically significant (P<0.05). However, frequencies recorded in 3a and 3b groups were not statistically different (P>0.05). Same results were obtained for enzyme analysis of MnSOD and glutathione peroxidase. Control group antioxidant enzyme levels were higher than patients' samples. The low antioxidant status of CPPS patients might be the clue for pathophysiological problems, and highly distributed Val allele frequency can be a mediator point of the illness. Our findings lead to the suggestion that oxidative disorder-linked medical health problems can be associated with genetic risk factors such as polymorphisms.