Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity （MIA）, secreted by malignant melanoma cells, int...Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity （MIA）, secreted by malignant melanoma cells, interacts with the cell adhesion receptors, integrins a4131 and 05131, facilitating cell detachment and promoting formation of me- tastases. In the present study, we demonstrate that MIA secretion is confined to the rear end of migrating cells, while in non-migrating cells MIA accumulates in the actin cortex. MIA protein takes a conventional secretory pathway including coat protein complex I （COPI）- and coat protein complex II （COPII）-dependent protein transport to the cell periphery, where its final release depends on intracellular Ca2＋ ions. Interestingly, the Ca2＋-activated K＋-channel, subfamily N, member 4 （KCa3.1）, known to be active at the rear end of migrating cells, was found to support MIA secretion. Secretion was diminished by the specific KCa3.1 channel inhibitor TRAM-34 and by expression of dominant- negative mutants of the channel. In summary, we have elucidated the migration-associated transport of MIA protein to the cell rear and also disclosed a new mechanism by which KCa3.1 potassium channels promote cell migration.展开更多
To evaluate a calcium activated potassium channel (KCa3.1) inhibitor attenuates liver disease in models of non-alcoholic fatty liver disease (NAFLD).METHODSWe have performed a series of in vitro and in vivo studies us...To evaluate a calcium activated potassium channel (KCa3.1) inhibitor attenuates liver disease in models of non-alcoholic fatty liver disease (NAFLD).METHODSWe have performed a series of in vitro and in vivo studies using the KCa3.1 channel inhibitor, Senicapoc. Efficacy studies of Senicapoc were conducted in toxin-, thioacetamide (TAA) and high fat diet (HFD)-induced models of liver fibrosis in rats. Efficacy and pharmacodynamic effects of Senicapoc was determined through biomarkers of apoptosis, inflammation, steatosis and fibrosis.RESULTSUpregulation of KCa3.1 expression was recorded in TAA-induced and high fat diet-induced liver disease. Treatment with Senicapoc decreased palmitic acid-driven HepG2 cell death. (P < 0.05 vs control) supporting the finding that Senicapoc reduces lipid-driven apoptosis in HepG2 cell cultures. In animals fed a HFD for 6 wk, co-treatment with Senicapoc, (1) reduced non-alcoholic fatty liver disease (NAFLD) activity score (NAS) (0-8 scale), (2) decreased steatosis and (3) decreased hepatic lipid content (Oil Red O, P < 0.05 vs vehicle). Randomization of TAA animals and HFD fed animals to Senicapoc was associated with a decrease in liver fibrosis as evidenced by hydroxyproline and Masson’s trichrome staining (P < 0.05 vs vehicle). These results demonstrated that Senicapoc mitigates both steatosis and fibrosis in liver fibrosis models.CONCLUSIONThese data suggest that Senicapoc interrupts more than one node in progressive fatty liver disease by its anti-steatotic and anti-fibrotic activities, serving as a double-edged therapeutic sword.展开更多
文摘Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity （MIA）, secreted by malignant melanoma cells, interacts with the cell adhesion receptors, integrins a4131 and 05131, facilitating cell detachment and promoting formation of me- tastases. In the present study, we demonstrate that MIA secretion is confined to the rear end of migrating cells, while in non-migrating cells MIA accumulates in the actin cortex. MIA protein takes a conventional secretory pathway including coat protein complex I （COPI）- and coat protein complex II （COPII）-dependent protein transport to the cell periphery, where its final release depends on intracellular Ca2＋ ions. Interestingly, the Ca2＋-activated K＋-channel, subfamily N, member 4 （KCa3.1）, known to be active at the rear end of migrating cells, was found to support MIA secretion. Secretion was diminished by the specific KCa3.1 channel inhibitor TRAM-34 and by expression of dominant- negative mutants of the channel. In summary, we have elucidated the migration-associated transport of MIA protein to the cell rear and also disclosed a new mechanism by which KCa3.1 potassium channels promote cell migration.
文摘To evaluate a calcium activated potassium channel (KCa3.1) inhibitor attenuates liver disease in models of non-alcoholic fatty liver disease (NAFLD).METHODSWe have performed a series of in vitro and in vivo studies using the KCa3.1 channel inhibitor, Senicapoc. Efficacy studies of Senicapoc were conducted in toxin-, thioacetamide (TAA) and high fat diet (HFD)-induced models of liver fibrosis in rats. Efficacy and pharmacodynamic effects of Senicapoc was determined through biomarkers of apoptosis, inflammation, steatosis and fibrosis.RESULTSUpregulation of KCa3.1 expression was recorded in TAA-induced and high fat diet-induced liver disease. Treatment with Senicapoc decreased palmitic acid-driven HepG2 cell death. (P < 0.05 vs control) supporting the finding that Senicapoc reduces lipid-driven apoptosis in HepG2 cell cultures. In animals fed a HFD for 6 wk, co-treatment with Senicapoc, (1) reduced non-alcoholic fatty liver disease (NAFLD) activity score (NAS) (0-8 scale), (2) decreased steatosis and (3) decreased hepatic lipid content (Oil Red O, P < 0.05 vs vehicle). Randomization of TAA animals and HFD fed animals to Senicapoc was associated with a decrease in liver fibrosis as evidenced by hydroxyproline and Masson’s trichrome staining (P < 0.05 vs vehicle). These results demonstrated that Senicapoc mitigates both steatosis and fibrosis in liver fibrosis models.CONCLUSIONThese data suggest that Senicapoc interrupts more than one node in progressive fatty liver disease by its anti-steatotic and anti-fibrotic activities, serving as a double-edged therapeutic sword.
文摘目的探讨溃疡性结肠炎(UC)血小板中钾通道和NLRP3的表达,以及与UC临床特征的关联分析。方法收集11例正常对照组和17例UC患者临床资料。提取血小板,采用RT-PCR、Western blot法检测Kca3.1、Kv1.3及NLRP3的表达水平。结果与正常对照组相比,UC患者血小板中Kca3.1、Kv1.3及NLRP3 m RNA表达量均明显增加(t=-6.067、-4.991、-18.981,P<0.05),与UC严重程度无明显相关。UC患者血小板中Kca3.1、Kv1.3及NLRP3蛋白表达量均明显高于对照组,差异有统计学意义(t=-9.627、-7.39、-7.821,P<0.05),与UC严重程度无明显相关。UC患者血小板中Kca3.1与NLRP3蛋白表达水平明显相关(r=0.877,P<0.05),Kv1.3与NLRP3蛋白表达水平有一定的相关性,但差异无统计学意义。UC患者血小板中Kca3.1、Kv1.3及NLRP3蛋白表达与患者临床指标红细胞沉降率、C反应蛋白及Mayo评分均不相关。结论 UC患者血小板中NLRP3与钾通道表达增高,两者具有一定相关。
