IL-4/Stat6 activities correlate with apoptosis and metastasis in colon cancer cells

IL-4-induced Stat6 signaling is active in a variety of cell types and plays a role in cell proliferation/growth and resistance to apoptosis. Using EMSA, we identified differential IL-4/Stat6 activities in colorectal cancer cell lines, HT-29 being active Stat6^high phenotype and Caco-2 being defective Stat6^null phenotype, respectively. Active Stat6^high HT-29 cells exhibited resistance to apoptosis by flowcytometry and aggressive metastasis by Transwell assay compared with defective Stat6^null Caco-2 cells. Comparing one another using RT-PCR, Stat6^high HT-29 cells expressed more mRNA of anti-apoptotic and pro-metastatic genes Survivin, MDM2, and TMPRSS4, while Stat6^null Caco-2 cells expressed more mRNA of pro-apoptotic and anti-metastatic genes BAX, CAV1, and P53, respectively. This is the first study describing correlations of IL-4/Stat6 activities with apoptosis and metastasis in colon cancer. These findings, together with the observation of constitutive Stat6 activation in many human malignancies, suggest that Stat6 activities could be a biomarker for cancer cell’s invasive/metastatic capability.     

Glucose induces apoptosis of cardiomyocytes via microRNA-1 and IGF-1

Glucose toxicity is an important initiator of cardiovascular disease, contributing to the development of cardiomyocyte death and diabetic complications. The present study investigated whether high glucose state could induce apoptosis of rat cardiomyocyte cell line H9C2 through microRNA regulated insulin-like growth factor (IGF-1) signaling pathway. Our data showed that H9C2 cells exposed to high glucose have increased miR-1 expression level, decreased mitochondrial membrane potential, increased cytochrome-c release, and increased apoptosis. Glucose induced mitochondrial dysfunction, cytochrome-c release and apoptosis was blocked by IGF-1. Using prediction algorithms, we identified 3′-untranslated regions of IGF-1 gene are the target of miR-1. miR-1 mimics, but not mutant miR-1, blocked the capacity of IGF-1 to prevent glucose-induced mitochondrial dysfunction, cytochrome-c release and apoptosis. In conclusion, our data demonstrate that IGF-1 inhibits glucose-induced mitochondrial dysfunction, cytochrome-c release and apoptosis and IGF-1’s effect is regulated by miR-1.     

Telmisartan inhibits methylglyoxal-mediated cell death in human vascular endothelium

Methylglyoxal (MGO) is a metabolite of glucose. Since serum MGO level is increased in diabetic patients, MGO is implicated in diabetic complications related to vascular injury. We have recently demonstrated that glucose metabolite is a more powerful stimulant for endothelial cells (ECs) injury rather than glucose or advanced glycation-end products. Recent clinical trials suggest that angiotensin receptor blockers are effective to prevent diabetes-associated cardiovascular disorders beyond blood pressure lowering effect. To explore the mechanisms, we examined effects of telmisartan on MGO-induced ECs injury. Treatment of human umbilical vein ECs with MGO (560 μM) induced time-dependent (0-24 h) cell death. MGO-induced cell death was apoptosis since MGO increased cleaved caspase-3 expression. Telmisartan (0.1-10 μM) inhibited MGO-induced cell death and caspase-3 activation. These results indicate that telmisartan prevents MGO-induced apoptosis by inhibiting caspase-3 activation, which might explain at least in part the beneficial effects of telimisartan against diabetes-related cardiovascular diseases.     

Differential effects of secreted frizzled-related proteins (sFRPs) on osteoblastic differentiation of mouse mesenchymal cells and apoptosis of osteoblasts

Secreted frizzled-related proteins (sFRPs) are modulators of Wnt signaling. This study was undertaken for definitive assessment of contribution of different sFRPs in osteoblastic differentiation of mesenchymal progenitor cells and apoptosis of osteoblasts. Treatment of C3H10T1/2 cells with sFRP-2 at concentrations of 10, 50, and 100 nM and sFRP-4 at low concentrations (5 nM) significantly increased Wnt-3A-induced alkaline phosphatase (ALP) activities, whereas sFRP-1 or 3 did not. Retroviral transduction of the sFRP-2 but not other sFRPs also significantly enhanced ALP activity induced by β-glycerophosphate and ascorbic acid. Furthermore, transfection of all the sFRP expression vectors significantly increased β-catenin/TCF reporter activity and the effects were most prominent with sFRP-2 and -4. In osteoblast apoptosis assay, only sFRP-3 increased etoposide-induced apoptosis in MC3T3-E1 mouse osteoblasts. In conclusion, we found that different repertoires of sFRPs exert differential effects on osteoblastic differentiation of mouse mesenchymal cells and cellular apoptosis of mouse osteoblasts in vitro.     

Interleukin-20 targets renal cells and is associated with chronic kidney disease

Interleukin (IL)-10 is an anti-inflammatory factor that suppresses renal fibrosis and improves renal function in CKD rats. IL-20 belongs to the IL-10 family; therefore, we sought to determine whether IL-20 is involved in CKD. CKD patients at stage five expressed significantly higher IL-20 in serum than controls. Immunohistochemical staining demonstrated that more IL-20 protein was expressed in the kidney tubular-epithelial cells, mesangial cells, and immune cells of CKD rats with a 5/6 nephrectomy. The lung, liver, and heart tissue of CKD rats also overexpressed IL-20. Thus, we treated two tubular epithelial cells, TKPTS and M-1 cells, with IL-20 to study its effects on CKD. IL-20 treatment induced apoptosis in these cells via caspase-3 activation. Incubating IL-20 with rat interstitial fibroblasts, NRK-49F cells, upregulated TGF-β1production, one key inducer for renal fibrogenesis. Therefore, IL-20 injured renal epithelial cells and induced fibroblasts to produce TGF-β1 that hastened the progression of CKD.     

Effect of Strontium Ranelate on Hydrogen Peroxide-Induced Apoptosis of CRL-11372 Cells

In vitro and in vivo studies have proven strontium to be an osteoinductive trace element. The effect of strontium ranelate (SR) on H₂O₂-induced apoptosis of CRL-11372 cells and optimization of its anti-apoptotic dose were the aims of this study. After 1 h of pretreatment with SR 1 μM, 50 μM, 100 μM, 500 μM, and 1,000 μM concentrations, CRL-11372 osteoblasts were exposed to 100 μM H₂O₂ for periods of 6–12 h. The same experiments were repeated without H₂O₂. The apoptotic index and viability of cells were assessed quantitatively with a fluorescent dye and qualitatively with agarose gel electrophoresis. Concentrations of 1–100 μM of SR with a 6-h treatment and only 1 μM concentration with a 12-h treatment inhibited the apoptotic effect of H₂O₂ on cultured osteoblasts significantly (P < 0.05). SR was shown to inhibit H₂O₂-induced apoptosis of CRL-11372 cells in a dose-dependent manner.     

胰岛细胞抗体分型与胰岛细胞凋亡的实验研究

研究通过大量临床糖尿病病人胰岛细胞抗体（Islet Cell Antibody,ICA)检测,发现ICA阳性反应有两种完全不同的形态学表现;弥漫型ICA和边缘型ICA,经免疫组织化学双标技术鉴别。弥漫型ICA可同时有着染α细胞和β细胞,边缘型ICA则仅着染α细胞。这种只着染α细胞的ICA国内外尚未见有报道,为探讨其在糖尿病发病中所起的作用。选择1型糖尿病（1-DM）的弥漫型ICA和边缘型ICA各3例。另选正常3例作对照,用患血清分别以2、4、8小时三个时相与分离并贴壁生长的正常人胰岛细胞孵育后,进行原位细胞凋亡检测。结果发现,弥漫型ICA,边缘型ICA均可导致胰岛细胞产生凋亡,其中弥漫型ICA使β细胞及α细胞出现凋亡;边缘型ICA使α细胞产生凋亡,这一结果提示;糖尿病发病机制除与分泌胰岛素的β细胞有密切关系的经典途径之外,可能还与分泌胰高血糖素的α细胞存在某种关系。     

Bcl-2在去甲二氢愈创木酸诱导恶性胶质瘤细胞凋亡中的变化

观察bcl-2在去甲二氢愈创木酸（NDGA）诱导恶性胶质瘤细胞系SHG-44细胞凋亡中的变化。利用光镜和电镜观察及TUNEL法检测培养细胞凋亡的情况。用免疫组织化学,原位杂交和图像分析等方法检测bcl-2基因mRNA和蛋白的表达水平。结果显示：（1）一定浓度的NDGA处理SHG-44细胞12-96h,均可诱导SHG-44细胞发生凋亡,且随着作用时间的延长,凋亡细胞数增加越明显;（2）免疫组织化学方法结果显示,NDGA处理细胞后,出现SHG-44细胞bcl-2蛋白表达水平降低,且随着作用时间的延长,这种趋势更加明显,与细胞凋亡的发生密切相关;（3）原位杂交结果显示,NDGA处理细胞不同时间后,出现SHG-44细胞bcl-2基因mRNA的表达水平降低,结果与免疫组织化学方法检测结果一致,上述结果表明,NDGA诱导SHG-44细胞凋亡过程中,bcl-2基因的表达降低,但其确切机制有待进一步深入研究。     

人胎视网膜SOD免疫阳性细胞的发育与细胞凋亡

选择不同胎龄的人胎18例,用免疫细胞化学ABC法和TUNEL法观察人胎视网膜超氧化物歧化酶（SOD）免疫阳性细胞的发育和细胞凋亡。结果显示;（1）E15w节细胞层开始出现SOD免疫阳性细胞,E20w和E28wSOD免疫阳性细胞排列较整齐,分布于视网膜的外核层,内核层,节细胞层;E40wSOD免疫阳性细胞主要集中于视网膜的外核层,内核层,节细胞层,其数量增多,特别是内核层SOD免疫阳性细胞增多明显。（2）TUNEL法标记的视网膜凋亡细胞胞核具有指环状典型的凋亡特征,E12w人胎视网膜未见凋亡细胞,E15w,E17w凋亡细胞较多,大小不一,分布于视网膜的全层;E20w凋亡细胞主要集中在内核层,数量减少,E28w凋亡细胞仅见于内核层,胞核呈指环样外观,着色较深,但数量较E20w进一步减少;E40w视网膜全层未见凋亡细胞。结果提示,E28w视网膜SOD抗氧化酶系,光感受的基本结构初步发育成熟,其抗氧化保护作用可能主要来源于内核层的SOD免疫阳性细胞。