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Aim: To study whether PC-407 [4-[5-naphthyl-3- (trifluoromethyl)-1H-pyrazol-1-yl] benzenesulfonamide] inhibits cell viability and induces apoptosis in human colon cancer SW-1116 cells., Methods: Inhibition of SW-1116 proliferation was measured by MTT assay. Morphological assessment of apoptosis was performed with fluorescence microscope and electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. The amount of apoptotic cells was measured by flow cytometry., Results: PC-407 inhibited SW-1116 cell proliferation in a concentration-dependent manner after 3 d of treatment, and the IC(50) for PC-407 inhibition of cell number was 16.67+/-0.17 micromol/L. After incubation of SW-1116 cells with PC-407 20 micromol/L for 24 h, morphological changes of typical apoptosis were observed by AO/EB staining or transmission electron microscopy. Flow cytometry analysis showed that PC-407 induced apoptosis in SW-1116 cells in a time- and concentration-dependent manner. The agarose gel electrophoresis of DNA revealed a ladder pattern 48 h later., Conclusion: PC-407 inhibited proliferation and induced apoptosis in the human colon cancer SW-1116 cell line.

Aim: To examine if estrogen can affect the immune response at the dendritic cells (DCs) level in rats with experimental autoimmune encephalomyelitis (EAE)., Methods: Lewis rats were immunized with inoculum containing MBP(68-86). DCs were derived from spleen monocytes of EAE rats with IL-4 and GM-CSF in presence of 17 beta-estradiol (E2). Nitric oxide (NO) was detected by Griess reagent. The surface markers and cytokines production of DCs were shown by flow cytometry. DCs were cocultured with MBP-specific T cells, [(3)H]-TdR incoportation was used to reveal the antigen presentability, the supernatant of the coculture were collected to examine the cytokines secretion by ELISA., Results: E2 activated DCs by accelerating the maturation process characterized by upregulation of MHC II and costimulating molecule B7-1, B7-2, drastic high expression of CD40. IFN-kappa-producing DCs were also elevated without any alteration of IL-10. Estradiol-treated DCs (E2-DCs) secreted more NO in the culture supernatant. By contrast, E2-DCs showed decreased antigen presentation ability with reduced secretion of IFN-kappa but no alteration of IL-10 in the coculture with T cells., Conclusion: Estrogen can affect the differentiation, maturation and function of DCs from EAE rats, which may be attributed to its protection against EAE and the remission of multiple sclerosis patients in pregnancy.

Aim: To study the effects of tumor necrosis factor-alpha (TNF-alpha) on calcium movement in rat ventricular myocytes., Methods: Intracellular free Ca2+ concentration was measured with calcium fluorescent probe Fluo-3/AM and laser confocal microscope. L-type calcium current (ICa,L) was recorded with the whole-cell configuration of the patch-clamp techniques., Results: At 2, 20 and 200 microg/L, TNF-alpha was found to increase intracellular free Ca2+ concentration in a dose-dependent manner illustrated by the increment of calcium fluorescence density with laser confocal microscope. Nicardipine 0.5 micromol/L slightly attenuated TNF-alpha-induced response. When the cardiac myocytes were exposed to caffeine (100 mmol/L) for 30 min, TNF-alpha failed to induce any change of intracellular free calcium. However, it was found that TNF-alpha inhibited I(Ca,L) in whole-cell patch-clamp experiments. At 2, 20, and 200 microg/L, TNF-alpha decreased peak I(Ca,L) by 3.9 % (-5.1 pA/pF+/-0.3 pA/pF vs -4.9 pA/pF+/-0.2 pA/pF, n=9, P>0.05), 15.7 % (-5.1 pA/pF+/-0.3 pA/pF vs -4.3 pA/pF+/-0.3 pA/pF, n=9, P<0.05) and 19.6 % (-5.1 pA/pF+/-0.3 pA/pF vs -4.1 pA/pF+/-0.4 pA/pF, n=9, P<0.01), respectively. It shifted the steady-state inactivation curve of I(Ca,L) to the left (V1/2 shifted from -28.7 mV+/-0.3 mV to -37.8 mV+/-1.4 mV, n=7, P<0.05), while it took no effects on steady-state activation and recovery from inactivation., Conclusion: TNF-alpha inhibited I(Ca,L) in rat ventricular myocytes, while increasing the intercellular free Ca2+ level due to the release of Ca2+ from intracellular stores.

Aim: To study the effects of serotonin (5-hydroxy-tryptamine, 5-HT) on transient outward potassium current (I(to)) and elucidate its mechanism in rat ventricular myocytes., Methods: I(to) was recorded using the conventional whole cell patch-clamp techniques., Results: I(to) density in normal myocytes was similar to that in norepinephrine-induced hypertrophic myocytes. 5-HT depressed I(to) in a concentration-dependent manner with the half-maximal inhibitory concentration of (40+/-5) micromol/L and (38+/-7) micromol/L in normal and hypertrophic ventricular myocytes respectively. Mianserin (5-HT2 receptor antagonist), compound 48/80 (phospholipase C antagonist), and chelerythrine chloride (protein kinase C antagonist) reversed the inhibitory effects of 5-HT on I(to), while phorbol 12-myristate 13-acetate (protein kinase C agonist) enhanced the inhibitory effect of 5-HT on I(to) in normal myocytes., Conclusion: 5-HT markedly inhibits I(to) in rat ventricular myocytes. The putative signal pathway is that 5-HT activates phospholipase C, which causes inositol phospholipid hydrolysis. The activation of downstream signal molecule, protein kinase C, phosphorates substrate target proteins, which leads to inhibition of I(to) in ventricular myocytes.

Aim: To study the effects of 5-hydroxytryptamine (5-HT) on L-type calcium current (ICa) in norepinephrine (NE)-induced hypertrophic ventricular myocytes., Methods: Left ventricular hypertrophy was induced by injecting NE intraperitoneally in rats. The single myocytes were isolated enzymatically from left ventricle. ICa was recorded with the whole-cell configuration of the patch-cl amp technique., Results: (1) The ratio of left heart weight to body weight (LHW/BW) was higher (P < 0.01) in the NE-treated rats compared with the control rats on d 15. LHW/BW was increased 31.8 % in NE-treated rats. (2) ICa was larger in hypertrophic cells than that in normal cells (4.5 p A/pF +/- 0.5 pA/pF vs 3.5 pA/pF +/- 0.3 pA/pF, respectively, at testing potential of 0 mV; P < 0.01). (3) 5-HT (1, 10 micromol/L) increased ICa and decreased the peak current potential from 0 mV to -10 mV in both myocytes. The augmentation of ICa induced by 5-HT was larger in hypertrophic ones. (4) 5-HT did not markedly influence the steady-state activation kinetics. However, 5-HT shifted steady-state inactivation curve with half inactivation voltage V 1/2 changing from -39.5 mV +/- 1.8 mV to -27.8 mV +/- 1.7 m V (P < 0.05), while not changing the voltage responsiveness of calcium channel (slope factor k was not changed markedly)., Conclusion: 5 -HT increased ICa in ventricular myocytes by changing the kinetics of steady-st ate inactivation. A larger alteration of ICa induced by 5-HT i n hypertrophic ventricular myocytes suggests that 5-HT be more prone to induce arrhythmia in hypertrophic heart than in normal one.