褪黑素对PDGF诱导的肝星状细胞中JAK2/STAT3信号通路的影响

目的探讨褪黑素对血小板衍生生长因子(PDGF)诱导的肝星状细胞-T6(HSC-T6)JAK2/STAT3信号通路的影响。方法将HSC-T6细胞分为6组:对照组、模型组、实验组(褪黑素1 nmol·L^-1、1μmol·L^-1、0.1 mmol·L^-1)、抑制剂组(AG490为JAK2/STAT3通路的抑制剂),MTT实验检测褪黑素对PDGF激活的HSC-T6细胞增殖的影响;免疫组化和Western blot检测褪黑素HSC-T6细胞中p-JAK2、p-STAT3蛋白的表达。结果与对照组比较,PDGF能明显激活HSC-T6细胞增殖,明显上调HSC-T6细胞中p-JAK2、p-STAT3的表达;与模型组比较,褪黑素和抑制剂均可抑制PDGF激活的HSC-T6细胞增殖,显著下调p-JAK2、p-STAT3的表达。结论褪黑素可抑制PDGF诱导的HSC-T6的活化与增殖,其机制可能与抑制JAK2/STAT3信号通路有关。     

Janus激酶-信号转导子与转录激活子信号通路在硫化氢后处理离体缺血再灌注大鼠心肌中的作用

目的 探讨Janus激酶-信号转导子与转录激活子(JAK2/STAT3)信号通路在硫化氢后处理(H2S)减轻离体大鼠心脏缺血/再灌注(I/R)损伤的作用.方法 应用Langendorff离体心脏灌流装置、通过停灌30 min/复灌60 min的方法建立SD大鼠I/R模型.按照处理及再灌注成分分为持续灌注对照组,I/R组...     

Acacetin restrains the malignancy of esophageal squamous carcinoma cells via regulating JAK2/STAT3 pathway

Acacetin is a natural flavonoid compound found in diverse plants, which has strong anti-inflammatory and anti-cancer activities. This work aimed at investigating how acacetin functions on esophageal squamous carcinoma cells. In this work, esophageal squamous carcinoma cell lines were subjected to increasing doses of acacetin, and the proliferative, migrative, invasive and apoptotic phenotypes were evaluated by a series of in vitro experiments. Genes related to acacetin and esophageal cancer were predicted by bioinformatics analysis. The levels of apoptosis-relevant proteins and JAK2/STAT3 pathway-relevant proteins in esophageal squamous carcinoma cells were probed by Western blot. It was revealed that acacetin could block the growth and aggressiveness of TE-1 and TE-10 cells and promote the apoptosis. Acacetin treatment induced bax's expression and repressed bcl-2's expression. Notably, acacetin inhibits JAK2/STAT3 pathway in esophageal squamous carcinoma cells. In summary, acacetin inhibits the malignant progression of esophageal squamous carcinoma via restraining JAK2/STAT3 signaling.     

JAK2/STAT3信号通路在人参皂苷Re预处理预防异丙肾上腺素致急性心肌缺血损伤中的作用

目的观察人参皂苷Re预处理对异丙肾上腺素致急性心肌缺血大鼠心肌JAK2/STAT3通路的影响。方法应用异丙肾上腺素建立SD大鼠急性心肌缺血模型,将75只大鼠随机分为空白对照组(Control)、模型组(Model)、葛根素对照组(PUE)、Re高剂量组(Re-H,20 mg·kg^-1)、Re低剂量组(Re-L,10 mg·kg^-1)。Moor激光血流成像系统观测各组大鼠心脏表面血流值;ELISA法测定各组大鼠心肌中CK、LDH、SOD、MDA、GSH的含量;免疫组化法检测Bax、Bcl-2蛋白表达;Western blot方法检测各组大鼠心肌JAK、p-JAK、STAT3、p-STAT3蛋白的表达变化。结果与对照组比较,模型组大鼠心脏表面平均血流量明显下降,心肌CK、LDH、MDA含量升高,GSH、SOD含量下降,Bcl-2/Bax比值下降(P<0.05),JAK2/STAT3通路蛋白的表达有所增加;与模型组比较,Re-H组心肌表面平均血流有明显提升(P<0.05);CK、LDH、MDA含量降低,GSH-Px含量升高(P<0.05),Bcl-2/Bax比值上升(P<0.05),JAK2/STAT3通路蛋白的表达明显增强(P<0.05)。结论人参皂苷Re预处理对急性心肌缺血大鼠心肌有较好的保护作用,该作用可能与JAK2/STAT3通路的激活有关。     

木犀草素抑制JAK2/STAT3信号通路减轻大鼠脑缺血 再灌注损伤作用的研究

目的 观察木犀草素减轻大鼠脑缺血再灌注损伤的作用并探讨其潜在机制。方法 SD大鼠按随机数字 表法分为假手术组、大脑中动脉栓塞（MCAO）组、木犀草素低剂量组（50 mg/kg）、木犀草素高剂量组（100 mg/kg）及尼 莫地平组（15 mg/kg）,灌胃给药,共7 d。采用线栓法建立MCAO大鼠模型,比较神经功能损伤评分、脑组织含水量、 脑梗死体积,测定各组肿瘤坏死因子α（TNF-α）、白细胞介素（IL）-6、IL-1β、B细胞淋巴瘤因子2（Bcl-2）、Bcl-2相关 X蛋白（Bax）、半胱氨酸蛋白酶3（Caspase-3）含量及磷酸化Janus蛋白酪氨酸激酶2（p-JAK2）、磷酸化信号转导及转 录激活蛋白3（p-STAT3）蛋白表达等变化情况。结果 与假手术组比较,MCAO组大鼠神经功能损伤评分、脑组织含 水量、脑梗死体积、脑组织TNF-α、IL-6、IL-1β、Bax、Caspase-3含量及JAK2、STAT3蛋白磷酸化水平均明显增加（P＜ 0.05）,而脑组织Bcl-2含量明显降低（P＜0.05）;与MCAO组比较,木犀草素低、高剂量组及尼莫地平组大鼠神经功能 损伤评分、脑组织含水量、脑梗死体积、脑组织TNF-α、IL-6、IL-1β、Bax、Caspase-3含量及JAK2、STAT3蛋白磷酸化 水平均明显降低（P＜0.05）,而脑组织Bcl-2含量明显增加（P＜0.05）。结论 木犀草素具有减轻大鼠脑缺血再灌注 损伤的作用,该作用与抑制JAK2/STAT3信号通路活化,进而减弱炎症反应及减少细胞凋亡有关。     

Photodynamic activity of BAM-SiPc, an unsymmetrical bisamino silicon(IV) phthalocyanine, in tumour-bearing nude mice

BACKGROUND AND PURPOSE: Ever since the discovery of photodynamic therapy, there has been a continuous search for more potent photosensitizers. Towards that end, we have synthesized a number of novel phthalocyanine derivatives. The unsymmetrical bisamino silicon(IV) phthalocyanine BAM-SiPc is one of the most potent compounds. In in vitro cell culture, it exhibits high phototoxicity against a number of cancer cell lines. EXPERIMENTAL APPROACH: In the present investigation, the in vivo effect of BAM-SiPc was studied in the tumour-bearing nude mice model. The biodistribution of BAM-SiPc was followed to evaluate its tumour selectivity and rate of clearance. The tumour volume in the hepatocarcinoma HepG2- and the colorectal adenocarcinoma HT29-bearing nude mice was measured after photodynamic therapy. The level of intrinsic toxicity induced was also investigated. Finally, the metabolism of BAM-SiPc in the 'normal' WRL68 liver cells and the hepatocarcinoma HepG2 cells was compared. KEY RESULTS: The results not only showed significant tumour regression of HepG2 and growth inhibition of HT29 in the tumour-bearing nude mice, but also no apparent hepatic or cardiac injury with the protocol used. Histological analyses showed that apoptosis was induced in the solid tumour. BAM-SiPc could be metabolized by WRL68 liver cells but not by the hepatocarcinoma HepG2 cells. Unfortunately, BAM-SiPc did not show any specific targeting towards the tumour tissue. CONCLUSIONS AND IMPLICATIONS: The efficiency of BAM-SiPc in inhibiting tumour growth makes it a good candidate for further evaluation. Enhancement of its uptake in tumour tissue by conjugation with biomolecules is currently under investigation.     

Inhibition of STAT3 expression by siRNA suppresses growth and induces apoptosis in laryngeal cancer cells

Aim: To determine the inhibitory effect of the synthetic STAT3 siRNA on the expression of STAT3 gene in human laryngeal cancer cell lines Hep2 and to investigate the effect of STAT3 siRNA on growth and apoptosis in Hep2 cells. Methods: A pair of DNA templates coding siRNA against STAT3-mRNA was synthesized to reconstruct plasmid of pSilencer1.0-U6 siRNA-STAT3. Hep2 cells were transfected with RPMI-1640 media (untreated), plasmid (empty), and STAT3 siRNA, respectively. Northern blot and Western blot analysis of STAT3 and pTyr-STAT3 expression in Hep2 cells and Western blot analysis of Bcl-2 expression in the Hep2 cell was performed 72 h after transfection. MTT, flow cytometry, and AO/EB assay were used for determination of cells proliferation and apoptosis in Hep2 cells. Results: pTyr-STAT3 was markedly expressed in untreated Hep2 cells and the vector-treated Hep2 cells, whereas pTyr-STAT3 expression was significantly reduced in STAT3 siRNA-transfected Hep2 cells, indicating that STAT3 siRNA inhibited the activity of STAT3. Transfection of Hep2 cells with STAT3 siRNA significantly inhibited STAT3 expression at both mRNA and protein level in Hep2 cells and the inhibition was characterized by time-dependent transfection. Treatment of Hep2 cells with STAT3 siRNA resulted in dose-dependent growth inhibition of Hep2, this significantly increased apoptotic cell rate, and decreased Bcl-2 expression level in Hep2 cells. STAT3 siRNA had an effect on induction of either early or late stage apoptosis. Conclusion: This study demonstrates that STAT3 siRNA effectively inhibits STAT3 gene expression in Hep2 cells leading to growth suppression and induction of apoptosis in Hep2 cells. The use of siRNA technique may provide a novel therapeutic approach to treat laryngeal cancer and other malignant tumors expressing constitutively activated STAT3.     

A new bisphosphonate derivative,CP, induces gastric cancer cell apoptosis via activation of the ERK1/2 signaling pathway

Aim： To investigate the effects of a new derivative of bisphosphonates, [2-（6-aminopurine-9-yl）-l-hydroxy-phosphine acyl ethyl] phosphonic acid （CP）, on human gastric cancer. Methods： Human gastric cancer cell lines （SGC-7901, BGC-823, MKN-45, and MKN-28） and human colon carcinoma cell lines （LoVo and HT-29） were tested. Cell growth was determined using the MTT assay. Flow cytometry, Western blot, caspase activity assay and siRNA transfection were used to examine the mechanisms of anticancer action. Female BALB/c nude mice were implanted with SGC- 7901 cells. From d6 after inoculation, the animals were injected with CP （200 pg/kg, ip） or vehicle daily for 24 d. Results： CP suppressed the growth of the 6 human cancer cell lines with similar IC5o values （3239 pmol/L）. In SGC-7901 cells, CP arrested cell cycle progression at the G2/M phase. The compound activated caspase-9, increased the expression of pro-apoptotic proteins Bax and Bad, decreased the expression of anti-apoptotic protein Bcl-2. Furthermore, the compound selectively activated ERK1/2 without affecting JNK and p38 in SGC-7901 cells. Treatment of SGC-7901 cells with the specific ERK1/2 inhibitor PD98059 or ERK1/2 siRNA hampered CP-mediated apoptosis. In the human gastric cancer xenograft nude mouse model, chronic administration of CP significantly retarded the tumor growth. Conclusion： CP is a broad-spectrum inhibitor of human carcinoma cells in vitro, and it also exerts significant inhibition on gastric cancer cell growth in vivo. CP induces human gastric cancer apoptosis via activation of the ERK1/2 signaling pathway.     

A new bisphosphonate derivative,CP, induces gastric cancer cell apoptosis via activation of the ERK1/2 signaling pathway

Aim:

To investigate the effects of a new derivative of bisphosphonates, [2-(6-aminopurine-9-yl)-1-hydroxy-phosphine acyl ethyl] phosphonic acid (CP), on human gastric cancer.

Methods:

Human gastric cancer cell lines (SGC-7901, BGC-823, MKN-45, and MKN-28) and human colon carcinoma cell lines (LoVo and HT-29) were tested. Cell growth was determined using the MTT assay. Flow cytometry, Western blot, caspase activity assay and siRNA transfection were used to examine the mechanisms of anticancer action. Female BALB/c nude mice were implanted with SGC-7901 cells. From d6 after inoculation, the animals were injected with CP (200 μg/kg, ip) or vehicle daily for 24 d.

Results:

CP suppressed the growth of the 6 human cancer cell lines with similar IC₅₀ values (3239 μmol/L). In SGC-7901 cells, CP arrested cell cycle progression at the G₂/M phase. The compound activated caspase-9, increased the expression of pro-apoptotic proteins Bax and Bad, decreased the expression of anti-apoptotic protein Bcl-2. Furthermore, the compound selectively activated ERK1/2 without affecting JNK and p38 in SGC-7901 cells. Treatment of SGC-7901 cells with the specific ERK1/2 inhibitor PD98059 or ERK1/2 siRNA hampered CP-mediated apoptosis. In the human gastric cancer xenograft nude mouse model, chronic administration of CP significantly retarded the tumor growth.

Conclusion:

CP is a broad-spectrum inhibitor of human carcinoma cells in vitro, and it also exerts significant inhibition on gastric cancer cell growth in vivo. CP induces human gastric cancer apoptosis via activation of the ERK1/2 signaling pathway.     

紫草素通过抑制STAT3-MMP2信号通路抑制胃癌MGC803细胞的迁移能力

目的:研究紫草素对人胃癌MGC803细胞迁移能力的影响,并探究其作用机制.方法:不同浓度的紫草素(0,1,2μg·mL-1)作用于人胃癌MGC803细胞,利用Transwell小室实验检测紫草素对人胃癌MGC803细胞侵袭和迁移能力的影响.进一步利用实时定量PCR和Western blot技术,检测不同浓度紫草素作用的...     

钙激活的氯离子通道 A4通过抑制 JAK激酶 2/信号转导及转录激活蛋白 3信号通路对食管癌细胞增殖、迁移及侵袭的影响

目的 探讨钙激活的氯离子通道A4(CLCA4)对食管癌细胞增殖、迁移、侵袭及JAK激酶2/信号转导及转录激活蛋白3(JAK2/STAT3)信号通路的影响.方法 实时荧光定量逆转录聚合酶链反应(qRT-PCR)与蛋白质印迹法(Western blotting)分别检测正常人食管鳞状上皮细胞与人食管癌细胞中CLCA4的表达;将合成的CLCA4过表达载体及其对照分别转染至食管癌细胞Eca109,分别记作CLCA4过表达(pcDNA-CLCA4)组、CLCA4阴性对照(pcDNA-NC)组,并将未转染的细胞作为阴性对照(NC)组.四甲基偶氮唑盐微量酶反应比色法(MTT法)检测细胞增殖能力;细胞迁移实验(Transwell)检测细胞迁移及侵袭能力.JAK2/STAT3信号通路激活剂p-JAK2多肽对细胞增殖、迁移及侵袭的影响.Western blotting检测细胞周期蛋白D1(Cy-clinD1)、依赖性激酶抑制因子(P21)、基质金属蛋白酶2(MMP-2)、基质金属蛋白酶9(MMP-9)、JAK2、STAT3、磷酸化JAK激酶2(p-JAK2)、磷酸化信号转导及转录激活蛋白3(p-STAT3)的表达水平.结果 与Het-1A相比,人食管癌细胞KYSE170、Eca109、TE10中CLCA4 mRNA及蛋白表达水平降低(P<0.05);与pcDNA-NC组比较,pcDNA-CLCA4组细胞存活率显著降低[(52.16±11.41)％比(99.57±13.49)％,P<0.05],迁移细胞数[(56.47±10.03)％比(112.49±13.52)％]与侵袭细胞数[(63.43±9.87)％比(123.47±16.58)％]减少(P<0.05),CyclinD1、MMP-2、MMP-9、p-JAK2、p-STAT3的表达水平降低(P<0.05),P21的表达水平升高(P<0.05);激活JAK2/STAT3信号通路可逆转CLCA4过表达对Eca109细胞增殖、迁移及侵袭的抑制作用.结论 CL-CA4过表达可抑制食管癌细胞增殖、迁移及侵袭,其作用机制可能与抑制JAK2/STAT3信号通路活化有关.     

以调控Ras信号传导为靶标的抗肿瘤药物研究进展

Ras信号转导途径与肿瘤发生和生长密切相关, 针对此信号通路重要靶点的药物设计是当前抗肿瘤药物研究的热点。本文综述了Ras蛋白及与其上下游信号转导途径相关的靶点及其抑制剂的研究现状, 为新型抗肿瘤药物的研究设计提供参考依据。     

Crotoxin induces apoptosis and autophagy in human lung carcinoma cells in vitro via activation of the p38MAPK signaling pathway

Aim:

Crotoxin (CrTX) is the primary toxin in South American rattlesnake (Crotalus durissus terrificus) venom, and exhibits antitumor and other pharmacological actions in vivo and in vitro. Here, we investigated the molecular mechanisms of the antitumor action of CrTX in human lung carcinoma cells in vitro.

Methods:

Human lung squamous carcinoma SK-MES-1 cells were tested. The cytotoxicity of CrTX was evaluated in both MTT and colony formation assays. Cell cycle was investigated with flow cytometry. Cell apoptosis was studied with Hoechst 33258 and Annexin V-FITC staining. The levels of relevant proteins were analyzed using Western blot assays.

Results:

CrTX (25, 50, 100 μmol/L) inhibited the growth and colony formation of SK-MES-1 cells in dose- and time-dependent manners. CrTX increased the proportion of S phase cells and dose-dependently induced cell apoptosis, accompanied by down-regulating the expression of proliferating cell nuclear antigen (PCNA), and increasing the level of cleaved caspase-3. Furthermore, CrTX dose-dependently increased the expression of autophagy-related proteins LC3-II and beclin 1, and decreased the level of p62 in the cells. Moreover, CrTX (50 μmol/L) significantly increased p38MAPK phosphorylation in the cells. Pretreatment of the cells with SB203580, a specific inhibitor of p38MAPK, blocked the inhibition of CrTX on cell proliferation, as well as CrTX-induced apoptosis and cleaved caspase-3 expression.

Conclusion:

The p38MAPK signaling pathway mediates CrTX-induced apoptosis and autophagy of human lung carcinoma SK-MES-1 cells in vitro.     

Involvement of the p38 MAPK signaling pathway in S‐phase cell‐cycle arrest induced by Furazolidone in human hepatoma G2 cells

Given the previously described essential role for the p38 mitogen‐activation protein kinase (p38 MAPK) signaling pathway in human hepatoma G2 cells (HepG2), we undertook the present study to investigate the role of the p38 MAPK signaling pathway in cell‐cycle arrest induced by Furazolidone (FZD). The aim of this study was to determine the effects of FZD on HepG2 cells by activating and inhibiting the p38 MAPK signaling pathway. The cell cycle and proliferation of HepG2 cells treated with FZD were detected by flow cytometry and MTT assay in the presence or absence of p38 MAPK inhibitors (SB203580), respectively. Cyclin D1, cyclin D3 and CDK6 were detected by quantitative real‐time PCR and western blot analysis. Our data showed that p38 MAPK became phosphorylated after stimulation with FZD. Activation of p38 MAPK could arise S‐phase cell‐cycle arrest and suppress cell proliferation. Simultaneously, inhibition of the p38 MAPK signaling pathway significantly prevented S‐phase cell‐cycle arrest, increased the percentage of cell viability and decreased the expression of cyclin D1, cyclin D3 and CDK6. These results demonstrated that FZD arose S‐phase cell‐cycle arrest via activating the p38 MAPK signaling pathway in HepG2 cells. Cyclin D1, cyclin D3 and CDK6 are target genes functioning at the downstream of p38 MAPK in HepG2 cells induced by FZD. Copyright © 2012 John Wiley & Sons, Ltd.     

Bigelovin inhibits STAT3 signaling by inactivating JAK2 and induces apoptosis in human cancer cells

Aim:

To study the function and mechanism of bigelovin, a sesquiterpene lactone from the flower of Chinese herb Inula hupehensis, in regulating JAK2/STAT3 signaling and cancer cell growth.

Methods:

HepG2 cells stably transfected with the STAT3-responsive firefly luciferase reporter plasmid (HepG2/STAT3 cells), and a panel of human cancer cell lines were used to identify active compounds. Cell viability was measured using MTT assay. Western blotting was used to detect protein expression and phosphorylation. Kinase assays were performed and the reaction between bigelovin and thiol-containing compounds was analyzed with LC-MS.

Results:

Bigelovin (1–50 μmol/L) dose-dependently inhibited the IL-6-induced STAT3 activation in HepG2/STAT3 cells (IC₅₀=3.37 μmol/L) and the constitutive STAT3 activation in A549 and MDA-MB-468 cells. Furthermore, bigelovin dose-dependently inhibited JAK2 phosphorylation in HeLa and MDA-MB-468 cells, as well as the enzymatic activity of JAK2 in vitro (IC₅₀=44.24 μmol/L). Pretreatment of the cells with DTT (500 μmol/L) or GSH (500 μmol/L) eliminated the inhibitory effects of bigelovin on the IL-6-induced and the constitutive STAT3 activation. The results in LC-MS analysis suggested that bigelovin might react with cysteine residues of JAK2 leading to inactivation of JAK2. Bigelovin (5 and 20 μmol/L) had no effects on the signaling pathways of growth factors EGF, PDGF or insulin. Finally, bigelovin suppressed the cell viability and induced apoptosis in 10 different human cancer cell lines, particularly those with constitutively activated STAT3.

Conclusion:

Bigelovin potently inhibits STAT3 signaling by inactivating JAK2, and induces apoptosis of a variety of human cancer cells in vitro.