PPARγ配体对人肺癌细胞95-D增殖的影响及机制探讨

目的观察过氧化物酶体增殖体激活受体γ（PPARγ）的合成配体曲格列酮（TGZ）和天然配体15-脱氧前列腺素J2（15-PGJ2）对肺癌95-D细胞增殖活性及凋亡的影响,并探讨其机制。方法将对数生长期的95-D细胞分为TGZ组、15-PGJ2组、对照组,分别加入500μl的TGZ溶液、15-PGJ2溶液、DMSO混合溶液培养;采用MTT法检测95-D细胞的增殖能力,采用流式细胞仪检测95-D细胞凋亡率和细胞周期变化,采用免疫细胞化学法检测95-D细胞中的PPARγ。结果与对照组比较,TGZ、15-PGJ2组95-D细胞增殖抑制率显著增加（P均〈0.01）,且存在时相性;95-D细胞凋亡率增加,S期细胞比例升高,G1期细胞比例降低;95-D细胞中PPARγ表达水平增加。结论PPARγ配体TGZ、15-PGJ2可抑制95-D细胞增殖,诱导其凋亡;该作用与PPARγ表达增加有关。     

Peroxisome Proliferator-Activated Receptor γ Negatively Regulates Allergic Rhinitis in Mice

BackgroundPeroxisome proliferator-activated receptor γ (PPAR-γ) has been shown to play an important role in the control of inflammatory responses acting on macrophages, mast cells, T cells, and eosinophils. The present study was aimed at investigating the effects of PPAR-γ agonist on nasal symptoms and eosinophil accumulations in nasal mucosa by using a murine allergic rhinitis model. Furthermore, we examined the expression of PPAR-γ in the nasal mucosa in mice.MethodsBALB/c mice were sensitized and challenged intranasally with ovalbumin. Ciglitazone, a PPAR-γ agonist, was administered orally 6 hours before each nasal challenge.ResultsAdministration of PPAR-γ agonist significantly decreased the number of nasal rubs, nasal histamine responsiveness, serum IgE, IL-5 production from the spleen, and eosinophilic infiltration in the nasal mucosa. Furthermore, PPAR-γ was expressed in eosinophils and epithelial cells in the nasal mucosa by immunohistochemistry.ConclusionsPPAR-γ was expressed in eosinophils and epithelial cells in the nasal mucosa. Also, the oral administration of ciglitazone is effective in upper airway allergic inflammation in mice.     

Differential expression of peroxisome proliferator activated receptor γ and cyclin D1 does not affect proliferation of asthma‐ and non‐asthma‐derived airway smooth muscle cells

Background and objective: Airway remodelling involves thickening of the airway smooth muscle (ASM) bulk. Proliferation of asthma‐derived ASM cells is increased in vitro, but underlying mechanisms remain unknown. Peroxisome proliferators activated receptor‐γ (PPARγ) regulates the cell cycle. It is suggested that PPARγ agonists have anti‐inflammatory effects, which may be valuable in the treatment of asthma, but information regarding their antiproliferative properties in ASM is lacking. Although corticosteroids reduce airway inflammation, in vitro they inhibit proliferation in only non‐asthma ASM cells by reducing cyclin D1. We therefore investigated the effects of mitogenic stimulation (foetal bovine serum (FBS)), and a PPARγ ligand (ciglitazone), on PPARγ and cyclin D1 expression and proliferation of ASM cells. In addition, we examined the effects of ciglitazone on ASM cell proliferation. Methods: We assessed PPARγ and cyclin D1 mRNA and protein levels using quantitative PCR and immunoblotting. Cell proliferation was assessed using bromodeoxyuridine uptake. Results: In the presence of 5% FBS, PPARγ and cyclin D1 expression decreased over time in non‐asthmatic cells but increased in asthmatic cells (compared with sub‐confluent cells). FBS‐induced proliferation of asthmatic cells increased at all time points, but occurred only at day 7 with non‐asthmatic cells (compared with unstimulated time‐matched control). Ciglitazone increased PPARγ expression in both groups, but did not alter cell proliferation, while fluticasone increased PPARγ protein only in asthmatic cells. Conclusions: Although in the presence of a mitogenic stimulus, PPARγ was differentially expressed in asthma‐ and non‐asthma‐derived ASM; its expression was not related to the increased proliferation observed in asthmatic ASM.     

Selective inhibition of cell growth by activin in SNU-16 cells

AIM: To investigate whether activin regulates the cell proliferation of human gastric cancer cell line SNU-16 through the mRNA changes in activin receptors, Smads and p21CIP1/WAF1. METHODS: The human gastric cancer cell lines were cultured, RNAs were purified, and RT-PCRs were carried out with specifically designed primer for each gene. Among them, the two cell lines SNU-5 and SNU-16 were cultured with activin A for 24, 48 and 72 h. The cell proliferation was measured by MTT assay. For SNU-16, changes in ActRⅠA, ActRⅠB, ActRⅡA, ActRⅡB, Smad2, Smad4, Smad7, and p21CIP1/WAF1 mRNAs were detected with RT-PCR after the cells were cultured with activin A for 24, 48 and 72 h. RESULTS: The proliferation of SNU-16 cells was down regulated by activin A whereas other cells showed no change. Basal level of inhibin/activin subunits, activin receptors, Smads, and p21CIP1/WAF1 except for activinβB mRNAs was observed to have differential expression patterns in the human gastric cancer cell lines, AGS, KATOⅢ, SNU-1, SNU-5, SNU-16, SNU-484, SNU-601, SNU-638, SNU-668, and SNU-719. Interestingly, significantly higher expressions of ActRⅡA andⅡB mRNAs were observed in SNU-16 cells when compared to other cells. After activin treatment, ActRⅠA,ⅠB, andⅡA mRNA levels were decreased whereas ActRⅡB mRNA level increased in SNU-16 cells. Smad4 mRNA increased for up to 48 h whereas Smad7 mRNA increased sharply at 24 h and returned to the initial level at 48 h in SNU-16 cells. In addition, expression of the p21CIP1/WAF1, the mitotic inhibitor, peaked at 72 h after activin treatment in SNU-16 cells. CONCLUSION: Our results suggest that inhibition of cell growth by activin is regulated by the negative feedback effect of Smad7 on the activin signaling pathway, and is mediated through p21CIP1/WAF1 activation in SNU-16 cells.     

Troglitazone, a peroxisome proliferator-activated receptor γ ligand, induces growth inhibition and apoptosis of HepG2 human liver cancer cells

AIM： To examine the effect of troglitazone, a peroxisome proliferator-activated receptor γ （PPARγ） ligand, on the proliferation and apoptosis of human liver cancer cells. METHODS： Liver cancer cell line HepG2 was cultured and treated with troglitazone. Cell proliferation was detected by 3-（4-,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide （MTT） assay; apoptosis was detected by flow cytometry and terminal deoxynucleotidyl transferase- mediated nick end labeling of DNA fragmentation sites （TUNEL） assay; and apoptosis-related protein was detected by immunocytochemistry and Western blotting. RESULTS： Troglitazone inhibited growth and induced apoptosis of HepG2 cells in a dose-dependent manner, and induced activation of caspase-3 expression. Troglitazone not only drove apoptosis-inhibiting factor survivin to translocate incompletely from the nucleus to the cytoplasm, but also inhibited expression of survivin, while it did not affect expression of apoptosis-promoting factor Bax. CONCLUSION： PPARγ ligands inhibit growth and induce apoptosis of liver cancer cells, and may have applications for the prevention and treatment of liver cancer.     

Troglitazone, a peroxisome proliferator-activated receptor γ ligand, induces growth inhibition and apoptosis of HepG2 human liver cancer cells

AIM: To examine the effect of troglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) ligand, on the proliferation and apoptosis of human liver cancer cells.METHODS: Liver cancer cell line HepG2 was cultured and treated with troglitazone. Cell proliferation was detected by 3-(4-,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay; apoptosis was detected by flow cytometry and terminal deoxynucleotidyl transferasemediated nick end labeling of DNA fragmentation sites (TUNEL) assay; and apoptosis-related protein was detected by immunocytochemistry and Western blotting.RESULTS: Troglitazone inhibited growth and induced apoptosis of HepG2 cells in a dose-dependent manner,and induced activation of caspase-3 expression.Troglitazone not only drove apoptosis-inhibiting factor survivin to translocate incompletely from the nucleus to the cytoplasm, but also inhibited expression of survivin,while it did not affect expression of apoptosis-promoting factor Bax.CONCLUSION: PPARγ ligands inhibit growth and induce apoptosis of liver cancer cells, and may have applications for the prevention and treatment of liver cancer.     

过氧化物酶增殖体激活受体-γ激动剂对急性肺损伤大鼠的保护作用及机制

目的 观察过氧化物酶增殖体激活受体-γ(PPAR-γ)激动剂对急性肺损伤大鼠的保护作用及其机制.方法 将72只Wistar大鼠按随机数字表法分为脂多糖组(32只)、曲格列酮干预组(32只)和对照组(8只).脂多糖组和曲格列酮干预组根据检测时间的不同再分为脂多糖及曲格列酮干预1、2、4、8 h组,每组各8只.脂多糖组静脉给予脂多糖(5 mg/kg),曲格列酮干预组在静脉注射脂多糖15 min后静脉给予曲格列酮(3 mg/kg).观察各组大鼠PaO2、肺组织髓过氧化物酶(MPO)活性、肺组织病理;采用RT-PCR法检测肺组织PPAR-γ、肿瘤坏死因子-γ(TNF-γ)mRNA表达;采用酶联免疫吸附法(ELISA)检测TNF-γ蛋白变化及用免疫组织化学观察肺组织PPAR-γ的改变;采用Western blot法测定肺组织核因子-γB(NF-γB)P65活性.采用SPSS 10.0软件进行统计学分析,各组间均数比较采用方差分析,均数两两比较采用q检验.结果 曲格列酮1、2、4、8 h组PaO2分别为(85±10)、(80±10)、(81±10)、(82±13)mm Hg(1 mm Hg=0.133 kPa),脂多糖组1、2.4、8 h组分别为(75±11)、(69±12)、(63±11)、(71±13)mm Hg,两组比较差异有统计学意义(F=4.32,P＜0.05);脂多糖2.4、8 h组MPO活性分别为(10.6±1.2)、(14.1±2.1)、(11.1±1.8)U/g,曲格列酮2、4、8 h组分别为(8.2±0.8)、(9.2±0.9)、(8.8±0.7)U/g,两组比较差异有统计学意义(F=14.99,P＜0.05);脂多糖1、2 h组肺组织TNF-γmRNA吸光度(A)值分别为0.68±0.07、0.92 ±0.05,曲格列酮1、2 h组分别为0.39±0.07、0.50±0.09,两组比较差异有统计学意义(q值分别为3.09、3.99,P＜0.05);脂多糖1、2 h组肺组织匀浆及血浆中TNF-?水平分别为(340±33)、(757±47)、(12.3±1.8)及(54.7±6.6)ng/L,曲格列酮1、2 h组为(306±30)、(685±47)、(10.0±1.7)及(46.8±5.9)ng/L,两组比较差异有统计学意义(q值分别为3.92、4.71、4.81、5.17,均P＜0.05);脂多糖1、2、4 h组肺组织PPAR-? mRNA表达(A值)分别为0.36±0.05、0.25±0.04、0.30±0.05,曲格列酮1、2.4 h干预组分别为0.39±0.02、0.44±0.05、0.46±0.04,两组比较差异有统计学意义(q值分别为6.13、5.69、3.72,均P＜0.05);脂多糖1、8 h组NF-?B P65由胞质向胞核移位(A值分别为0.81±0.14、1.91±0.16、0.33±0.06及2.01±0.18),曲格列酮1、8 h组分别为1.14±0.15、1.06±0.21、0.81±0.14、1.03±0.18,两组比较差异有统计学意义(q值分别为3.29、6.25、5.59、6.81,均P＜0.05).结论 在脂多糖诱发的大鼠急性肺损伤模型中,曲格列酮通过上调PPAR-γ表达来抑制NF-γB活性,使NF-γB调控的炎症介质表达下调,炎性细胞浸润和活化减少,从而保护肺组织.     

过氧化物酶体增殖物激活受体-γ和血管紧张素Ⅱ受体在慢性胰腺炎组织中的表达及意义

目的 观察过氧化物酶体增殖物激活受体-γ(PPAR-γ)和血管紧张素Ⅱ受体(AT1R和AT2R)在慢性胰腺炎(CP)组织中的表达,探讨其意义.方法 收集2006年4月至2009年2月经病理确诊的CP 24例,以12例正常胰腺组织作为对照.采用免疫组化方法检测胰腺组织PPAR-γ和AT1R、AT2R的表达.结果 正常胰腺组织PPAR-γ和AT1R蛋白多旱阴性表达,阳性分值分别为0.33±0.49和0.42±0.51;AT2R蛋白在腺泡、胰岛细胞可呈阳性或弱阳性表达,在导管细胞质呈弱阳性表达,分值为2.33±1.37.CP组织PPAR-γ、AT1R和AT2R在腺泡、导管、间质及胰岛细胞中均可有不同程度表达,阳性分值分别为3.28±2.46、4.36±2.80和4.61±2.89,均显著高于正常对照组(P值分别为<0.01、<0.01、<0.05).结论 PPAR-γ和AT1R、AT12R在CP组织中均呈高表达,这可能是CP药物治疗的潜在靶点.     

血管紧张素Ⅱ受体阻滞剂对PPAR-γ的激活作用

目的通过观察血管紧张素Ⅱ受体阻滞剂（ARB）对过氧化物酶体增殖物激活受体（PPAR）的作用,探讨其改善糖脂代谢的机制。方法用双荧光素酶基因报告系统构建PPARs配体筛选系统检测荧光素酶活性,以反映厄贝沙坦及替米沙坦对PPAR启动子激活程度。应用RT-PCR测定厄贝沙坦及替米沙坦PPAR-γmRNA表达活性。结果厄贝沙坦及替米沙坦均可呈剂量及时间依赖性增强COS-7细胞PPAR-γ启动子表达活性,呈剂量依赖性增强3T3-L1细胞PPAR-γmRNA表达。结论可能为PPAR-γ激动剂通过激活PPARs系统来发挥其改善代谢的作用。     

Stimulation of resorption in cultured mouse calvarial bones by thiazolidinediones

Dosage-dependent release of 45Ca was observed from prelabeled mouse calvarial bones after treatment with two thiazolidinediones, troglitazone and ciglitazone. Release of 45Ca by ciglitazone was decreased by the osteoclast inhibitors acetazolamide, calcitonin, 3-amino-1-hydroxypropylidene-1,1-bisphosphonate, and IL-4, but not affected by the peroxisome proliferator-activated receptor gamma antagonist, GW 9662, the mitotic inhibitor, hydroxyurea, or indomethacin. Enhanced expression of receptor activator of nuclear factor-kappaB ligand (RANKL) mRNA and protein and decreased osteoprotegerin (OPG) mRNA and protein were noted after ciglitazone treatment of calvariae. Ciglitazone and RANKL each caused increased mRNA expression of osteoclast markers: calcitonin receptor, tartrate-resistant acid phosphatase, cathepsin K, matrix metalloproteinase-9, integrin beta3, and nuclear factor of activated T cells 2. OPG inhibited mRNA expression of RANKL stimulated by ciglitazone, mRNA expression of osteoclast markers stimulated by ciglitazone and RANKL, and 45Ca release stimulated by troglitazone and ciglitazone. Increased expression of IL-1alpha mRNA by ciglitazone was not linked to resorption stimulated by the thiazolidinedione. Ciglitazone did not increase adipogenic gene expression but enhanced osteocalcin mRNA in calvariae. In addition to exhibiting sensitivity to OPG, data indicate that stimulation of osteoclast differentiation and activity by thiazolidinediones may occur by a nonperoxisome proliferator-activated receptor gamma-dependent pathway that does not require cell proliferation, prostaglandins, or IL-1alpha but is characterized by an increased RANKL to OPG ratio.     

Troglitazone inhibits tumor growth in hepatocellular carcinoma in vitro and in vivo

Peroxisome proliferator-activated receptor gamma (PPARgamma) has been implicated in the differentiation and growth inhibition of cancer cells. We examined the effects of PPARgamma activation by troglitazone on hepatocellular carcinoma (HCC) cell growth, proliferation, and apoptosis in vitro and in vivo. We also studied relationships between PPARgamma activation and cyclooxygenase-2 (COX-2) expression. Human HCC cell lines Huh7 and Hep3B were cultured in the presence or absence of troglitazone. Cell growth was determined via WST-1 assay, proliferation by cell cycle analysis and proliferating cell nuclear antigen (PCNA) Western blotting, and apoptosis by flow cytometry and TUNEL. Tumor growth after subcutaneous implantation of Huh7 cells in nude mice was monitored, and the effects of treatment with troglitazone were determined. In resected HCCs, PPARgamma expression was less compared with the histologically normal surrounding liver. In cultures of Hep3B and Huh7 cells, basal expression of PPARgamma was relatively low, but troglitazone caused dose-dependent induction of PPARgamma expression. Cell cycle analysis revealed a decreased proportion of cells in S phase, with arrest at G0/G1. Concomitant downregulation of PCNA and an increase in TUNEL staining, cells were consistent with decreased proliferation and induction of apoptosis by troglitazaone. Troglitazone-mediated PPARgamma activation also suppressed COX-2 expression and induced p27 in HCC cells. Administration of troglitazone to Huh7 tumor-bearing mice significantly reduced tumor growth and caused tumor regression. In conclusion, collectively, these results indicate that PPARgamma could be a regulator of cell survival and growth in HCC. PPARgamma therefore represents a putative molecular target for chemopreventive therapy or inhibition of liver cancer growth.     

Troglitazone inhibits oxidized low-density lipoprotein-induced macrophage proliferation: impact of the suppression of nuclear translocation of ERK1/2

Thiazolidinediones (TZDs), which were known as novel insulin-sensitizing antidiabetic agents, have been reported to inhibit the acceleration of atherosclerotic lesions. Macrophages play important roles in the development of atherosclerosis. We previously reported that oxidized low-density lipoprotein (Ox-LDL) induces macrophage proliferation through ERK1/2-dependent GM-CSF production. In the present study, we investigated the effects of two TZDs, troglitazone and ciglitazone on Ox-LDL-induced macrophage proliferation. Troglitazone significantly inhibited Ox-LDL-induced increases in [(3)H]thymidine incorporation into and proliferation of mouse peritoneal macrophages, whereas ciglitazone had no effects. Troglitazone and ciglitazone both significantly induced PPARgamma activity, suggesting that the inhibitory effect of troglitazone was not mediated by PPARgamma. Ox-LDL-induced production of GM-CSF was significantly inhibited by troglitazone, but not by ciglitazone. Troglitazone inhibited Ox-LDL-induced production of intracellular reactive oxygen species, whereas ciglitazone had no effect. The antioxidant reagents NAC and NMPG each inhibited phosphorylation of ERK1/2, whereas troglitazone and ciglitazone had no effects. However, troglitazone, NAC and NMPG all inhibited nuclear translocation of ERK1/2. In conclusion, troglitazone inhibited Ox-LDL-induced GM-CSF production by suppressing nuclear translocation of ERK1/2, thereby inhibiting macrophage proliferation. This suppression of macrophage proliferation by troglitazone may, at least in part, explain its antiatherogenic effects.     

Absence or decreased levels of the hMLH1 protein in human gastric carcinoma cell lines: implication of hMLH1 in alkylation tolerance

Defective hMLH1 function has been increasingly associated with acquired cellular resistance to DNA alkylation damage in human colorectal and endometrial cancer cells. To investigate the relationship between the DNA alkylation tolerance and the hMLH1 status in human gastric carcinoma cells, we determined the cellular response to N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), the mutational changes, and the expression of hMLH1 in 11 human gastric carcinoma cell lines. Of 11 cell lines, 4 (SNU-5, -16, -620, and -719) were sensitive, whereas 7 (SNU-1, -216, -484, -520, -601, -638, and -668) were resistant to the cytotoxic effect of MNNG. As determined by Western analysis, it was evident that all the MNNG-resistant cell lines except one (SNU-601) produced very low or undetectable levels of hMLH1 protein compared to the MNNG-sensitive cell lines. A homozygous non-sense mutation that resulted in truncated protein was found in one MNNG-resistant cell line (SNU-1). Therefore, to determine whether the sensitivity of cells to MNNG can be restored by exogenous expression of hMLH1 protein, wild-type hMLH1 cDNA was introduced into the MNNG-resistant cells (SNU-1). The cytotoxicity test showed that expression of exogenous wild-type hMLH1 protein caused an increase in sensitivity to the cytotoxic effect of MNNG. This restoration was confirmed by an increase in the cell population containing less than the G1 amount of DNA (cell death) in the wild-type hMLH1-transfected cells, as determined by flow cytometry analysis. Together our results suggest that (1) the absence or decreased level of wild-type hMLH1 protein may be a frequent event in the human gastric carcinoma cell lines, (2) such alterations in the hMLH1 protein are closely associated with the MNNG tolerance in the human gastric carcinoma cell lines, and (3) the hMLH1 protein participates not only in the repair of DNA mismatches but also in the mechanism of escape from the cytotoxic effects of DNA alkylation damage. Received: 26 January 1998 / Accepted: 18 March 1998     

血管紧张素Ⅱ对巨噬细胞和泡沫细胞ACAT-1及PPAR-γ表达的影响

目的:观察血管紧张素Ⅱ(Ang Ⅱ)对巨噬细胞和泡沫细胞过氧化体增殖物激活型受体γ(PPAR-γ)和酰基辅酶A:胆同醇酰基转移酶-1(ACAT-1)表达的影响.方法:将单核细胞株THP-I与160 nmol/L佛波酯(PMA)孵育48 h,使之分化为巨噬细胞,继以100 mg/L氧化型低密度脂蛋白(ox-LDL)诱导巨...