STAT5通路抑制剂对脂多糖诱导RAW264.7细胞的保护作用研究

目的观察信号传导及转录激活因子(STAT)5通路抑制剂对经脂多糖(LPS)诱导的小鼠巨噬细胞RAW264.7细胞株一氧化氮(NO)和诱导型一氧化氮合成酶(iNOS)表达的影响。方法将处于对数期的RAW264.7细胞分为空白对照组、STAT5通路抑制剂对照组、LPS诱导组和STAT5通路抑制剂低、中、高浓度组,实时定量聚合酶链式反应(RT-PCR)法测定iNOS mRNA的表达量,Western blot测定iNOS以及磷酸化STAT5(p-STAT5)的蛋白表达量。结果RAW264.7细胞培养24 h后,空白对照组、STAT5通路抑制剂对照组、LPS诱导组以及STAT5通路抑制剂低、中、高浓度组细胞中NO的含量差异有统计学意义(F=25.69,P<0.05);低、中、高浓度STAT5通路抑制剂对RAW264.7细胞释放NO的抑制率差异有统计学意义(F=132.49,P<0.05)。空白对照组、STAT5通路抑制剂对照组、LPS诱导组和STAT5通路抑制剂低、中、高浓度组细胞iNOS mRNA以及蛋白质的表达量比较差异有统计学意义(F=123.59、23.37,P<0.05)。空白对照组、STAT5通路抑制剂对照组、LPS诱导组和STAT5通路抑制剂低、中、高浓度组细胞p-STAT5/STAT5表达比较差异有统计学意义(F=12.07,P<0.05)。结论STAT5通路抑制剂能够抑制RAW264.7细胞iNOS的表达以及NO的产生,其机制可能与抑制STAT5磷酸化的表达有关。     

Okra polysaccharide-2 plays a vital role on the activation of RAW264.7 cells by TLR2/4-mediated signal transduction pathways

Polysaccharide is the main active component of okra (Abelmoschus esculentus L.) and it can effectively stimulate the activation of macrophages. However, the immune regulatory mechanism is still not clear. Therefore, the present study aimed to reveal the possible mechanism by investigating the effect of okra polysaccharide-2 (RPS-2) on Toll-like receptor (TLR) 2/4-mediated signal transduction pathways in RAW264.7 murine macrophage cells. In order to confirm whether RPS-2 stimulated macrophages activation via TLR2 or TLR4, RAW264.7 murine macrophage cells were pretreated with TLR2/4 inhibitors for 1 h before RPS-2 treatment, and then the NO, IL-10, TNF-α levels were tested. The results indicated that both TLR2 and TLR4 were the keys of immune regulatory effect of RPS-2. Afterwards, the effect of RPS-2 on NF-κB and MAPKs signaling pathways were studied by western blot analysis. It showed RPS-2 induced the phosphorylation of p65, IκBα, p38, ERK1/2 and JNK. At the same time, the specific inhibitors reduced these phosphorylation levels as well as NO, IL-10 and TNF-α amounts. In a word, RPS-2 activated macrophages by NF-κB and MAPKs signal transduction pathways.     

醉茄素A通过JAK/STAT通路对人肝癌耐药细胞HepG2/ADM凋亡的影响

目的研究醉茄素A通过Janus激酶(JAK)/信号转导与转录激活子(STAT)通路对人肝癌耐药细胞HepG2/阿霉素(ADM)凋亡的影响,并探讨JAK/STAT通路在其中可能的作用机制。方法体外培养HepG2/ADM细胞,分为对照组、醉茄素A 2.5、5.0、10.0μmol/L组。CCK-8法检测细胞增殖情况;Hoechst33342染色法观察细胞形态学变化;Annexin V-FITC/PI双染色法检测细胞凋亡情况;Western blotting法检测凋亡相关蛋白B淋巴细胞瘤-2(Bcl-2)、cleaved caspase-3以及JAK/STAT通路中磷酸化JAK2(p-JAK2)、STAT3(p-STAT3)蛋白表达情况。结果醉茄素A 2.5、5.0、10.0μmol/L组HepG2/ADM细胞增殖受到明显抑制,并呈时间和剂量相关性(P<0.05)。与对照组相比,醉茄素A 2.5、5.0、10.0μmol/L组HepG2/ADM细胞部分细胞核发生碎片化、固缩,荧光强度增大,细胞凋亡指数及凋亡率显著升高(P<0.05),cleavedcaspase-3蛋白表达水平显著升高(P<0.05),Bcl-2、p-JAK2、p-STAT3蛋白表达水平显著降低(P<0.05)。结论醉茄素A可促进人肝癌耐药细胞Hep G2/ADM凋亡,其机制可能与抑制JAK/STAT通路活化,下调抑凋亡蛋白表达及上调促凋亡蛋白表达有关。     

Induction of differentiation in human myeloid leukemic cells by T-2 toxin and other trichothecenes

Trichothecenes are sesquiterpen mycotoxins characterized by the tetracyclic 12,13-epoxytrichothec-9-ene skeleton. We determined the effect of these mycotoxins on the growth and differentiation of the human acute promyelocytic leukemia (HL-60) cell line. Sixteen natural and semisynthetic trichothecenes were tested at concentrations of 0.2-60,000 ng/ml. The cytotoxicity exerted by these compounds varied: e.g., roridin A was found to be toxic at 1 ng/ml, whereas T-2 palmitate was not toxic even at 1 microgram/ml. These compounds varied also in their potential to induce differentiation: 9,10-epoxy T-2 toxin and T-2 toxin induced differentiation at concentrations of 2-5 ng/ml, while 9,10-dihydro T-2 toxin was effective only at 100 ng/ml. Other trichothecenes (e.g., verrucarin A and verrucarol) did not induce differentiation at either subtoxic or toxic concentrations. Cell differentiation was always associated with cytotoxicity; optimal concentrations for induction of differentiation were usually 30-60% of the toxic concentrations. The HL-60 cell population was found to be heterogenous with respect to the ability to differentiate in response to trichothecenes, while in some clones up to 70% of the cells underwent differentiation, and other clones were completely resistant. The latter clones could, however, be induced to differentiate by other agents such as retinoic acid, dimethyl sulfoxide and 12-O-tetradecanoylphorbol-13-acetate. Some of the inducible clones differentiated into neutrophilic granulocytes while others into mature macrophages. Thus, a single trichothecene could induce differentiation into either cell types, depending on the clone used. This study presents a new group of differentiation inducers. Further investigation is required to evaluate their possible therapeutic application.     

T-2 toxin induces apoptosis, and selenium partly blocks, T-2 toxin induced apoptosis in chondrocytes through modulation of the Bax/Bcl-2 ratio.

T-2 toxin is one of the mycotoxins, a group of type A trichothecenes produced by several fungal genera including Fusarium species. In the present study, we have investigated the apoptotic effects of T-2 toxin on chondrocytes and the relationship between T-2 toxin induced chondrocyte apoptosis and its influence on Bcl-2/Bax protein and mRNA expression. We have also examined the inhibitory effects of selenium on chondrocyte apoptosis induced by T-2 toxin. We have combined morphological and biological techniques to establish the relevance of apoptosis in human chondrocyte death induced by T-2 toxin. Treatment with T-2 toxin caused accelerated apoptosis in a concentration dependent manner. The apoptosis induced by T-2 toxin involved an increased Bax/Bcl-2 ratio. Bcl-2 mRNA expression remained unchanged in chondrocyte apoptosis induced by T-2 toxin treatment, while Bax mRNA expression increased following treatment with T-2 toxin. Selenium could partly block the apoptosis of chondrocytes induced by T-2 toxin through decreasing the Bax/Bcl-2 ratio. These results suggest that, under our experimental conditions, apoptosis of chondrocytes can be induced by T-2 toxin (1-20ng/mL) via the Bcl-2 and Bax proteins, and the Bax/Bcl-2 ratio may play a critical role in governing the susceptibility to apoptosis induced by T-2 toxin in human chondrocytes.     

JAK2/STAT3信号转导通路在子宫内膜异位症发病过程中的作用

目的 研究JAK2/STAT3信号转导通路在子宫内膜异位症 （EMS） 发展过程中的作用。方法 将60只大鼠随机分为假手术组、 模型组、 JAK2/STAT3通路抑制剂组 （AG组）, 每组20只。模型组、 AG组大鼠通过自身子宫内膜移植建立EMS模型。AG组造模前给予AG490 1 mg/kg, 手术后给予AG490 4 mg/kg, 每周2次, 连续4周; 模型组给予生理盐水。处理结束后记录各组大鼠异位内膜体积, 计算异位内膜生长抑制率, HE染色观察病理改变; 蛋白质印迹法 （Western blot） 检测内膜组织中p-JAK2、 JAK2、 p-STAT3、 STAT3蛋白表达水平。结果 治疗后AG组异位内膜组织生长发育不良, 异位内膜体积明显小于模型组, 异位内膜生长的抑制率为65.66%。Western blot结果显示, EMS模型大鼠异位内膜病灶中JAK2、 STAT3总蛋白及其磷酸化水平 （p-JAK2/JAK2、 p-STAT3/STAT3） 明显高于假手术组; 而 AG组大鼠异位内膜病灶中JAK2、 STAT3总蛋白及其磷酸化水平明显低于模型组。结论 JAK2/STAT3通路在EMS 发病过程中可能发挥了重要作用, 而抑制JAK2/STAT3信号通路则能够对EMS的治疗产生积极作用。     

Autophagy plays a protective role against apoptosis induced by toxicarioside N via the Akt/mTOR pathway in human gastric cancer SGC-7901 cells

Toxicarioside N (Tox N), a natural product extract from Antiaris toxicaria, has been reported to induce apoptosis in human gastric cancer cells. However, the mechanism and actual role of autophagy in Tox N-induced apoptosis of human gastric cancer cells remains poorly understood. In the current study, we demonstrated that Tox N could induce autophagy by inhibiting the Akt/mTOR signaling pathway in SGC-7901 cells. Moreover, we found that the inhibition of autophagy by 3-methyladenine, an autophagy inhibitor, enhanced Tox N-induced apoptotic cell death. However, the stimulation of autophagy by rapamycin, an autophagy activator, remarkably suppressed Tox N-induced apoptosis, suggesting that autophagy plays a protective role in Tox N-induced apoptosis. Thus, the results from this study suggested that Tox N combination with an autophagy inhibitor might be a promising strategy to enhance the anticancer activity of Tox N for the treatment of human gastric cancer.     

积雪草酸调控JAK2/STAT3信号通路对前列腺癌细胞凋亡的影响

目的 分析艾地苯醌联合倍他司汀治疗脑梗死后认知功能障碍的临床疗效。方法 选取2020年1月-2021年10月长治医学院附属和平医院98例脑梗死后认知功能障碍患者,采用区组随机分组法分为对照组(49例)和治疗组(49例)。对照组口服盐酸倍他司汀片,8 mg/次,3次/d。治疗组在对照组基础上口服艾地苯醌片,30 mg/次,3次/d。两组患者均治疗2个月。观察两组患者临床疗效,比较治疗前后两组患者血液流变学指标血细胞比容(HCT)、纤维蛋白原(FIB)和血小板黏附率(PAR)水平,氧化应激指标超氧化物歧化酶(SOD)和丙二醛(MDA)水平,神经功能指标视锥蛋白样蛋白-1(VILIP-1)、胰岛素样生长因子-1(IGF-1)和脑源性神经营养因子(BDNF)水平。结果 治疗后,治疗组总有效率(95.92%)较对照组(79.59%)明显升高(P<0.05)。治疗1、2个月,两组HCT、FIB、PAR、MDA、VILIP-1水平明显低于治疗前(P<0.05),且治疗2个月时低于治疗1个月(P<0.05);治疗1、2个月,治疗组这些指标低于同期对照组(P<0.05);治疗1、2个月,两组简易智能精神状态量表(MMSE)评分、SOD、IGF-1及BDNF水平高于治疗前(P<0.05),且治疗2个月高于治疗1个月(P<0.05);治疗1、2个月,治疗组这些指标高于同期对照组(P<0.05)。结论 艾地苯醌联合倍他司汀用于脑梗死后认知功能障碍可提高疗效,加快恢复认知功能,促进神经功能、血液流变学改善,抑制氧化应激损伤,安全可靠。     

JAK2/STAT3信号转导通路在岩大戟内酯B诱导的前列腺癌细胞PC-3凋亡中的作用

目的探讨岩大戟内酯B诱导的人前列腺癌细胞系PC-3细胞凋亡以及JAK2/STAT3信号转导通路在此过程中的作用。方法不同浓度的岩大戟内酯B处理人前列腺癌细胞系PC-3细胞0、24、48、72 h后,采用台盼蓝染色法检测PC-3细胞存活率;采用Annexin V-FITC/PI双染流式细胞仪检测PC-3细胞凋亡率;Western blot分析检测岩大戟内酯B作用不同时间后JAK2/STAT3信号转导通路的表达;预先用不同浓度的JSI-124(选择性STAT3途径抑制剂)处理PC-3细胞60 min,观察岩大戟内酯B作用不同时间后PC-3细胞的凋亡情况。结果岩大戟内酯B能够诱导前列腺癌细胞PC-3凋亡,降低磷酸化-JAK2/STAT3的表达,JSI-124可以提高岩大戟内酯B诱导的PC-3细胞凋亡率。结论 JAK2/STAT3信号转导通路参与了岩大戟内酯B诱导的PC-3细胞凋亡过程。JSI-124通过特异性地抑制STAT3活性提高了岩大戟内酯B诱导的PC-3细胞凋亡率。     

PI3K信号通路在LPS诱导RAW264.7细胞表达sTREM-1中的作用

目的：探讨磷脂酰肌醇3-激酶(PI3K)信号通路在脂多糖(LPS)诱导RAW264.7细胞表达可溶性髓样细胞触发受体-1(sTREM-1)中的作用。方法培养小鼠巨噬细胞株RAW264.7,采用相同浓度的LPS在不同时间诱导RAW264.7细胞,应用Western blot法分别检测PI3K蛋白表达水平,RT-PCR法检测PI3K mRNA表达水平,酶联免疫吸附(ELISA)法检测细胞培养血清中sTREM-1表达水平。用不同浓度PI3K特异性抑制剂LY294002处理细胞,观察上述指标变化。结果 LPS可时间依赖性地诱导RAW264.7细胞PI3K蛋白、PI3K mRNA的表达;LY294002可浓度依赖性地抑制PI3K蛋白、PI3K mRNA的表达;LY294002阻断PI3K信号转导通路后,LPS对sTREM-1表达的诱导作用受到显著抑制,并且具有剂量依赖性。结论 LPS通过PI3K信号通路诱导RAW264.7细胞表达sTREM-1。     

Toxicity and oxidative stress induced by T-2 toxin in cultured mouse Leydig cells

To explore the toxic mechanism of T-2 toxin on Leydig cells of mice, we would investigate the toxicity and oxidative stress induced by T-2 toxin in the cells. Leydig cells were isolated and cultured with control or T-2 toxin (10^?7 M, 10^?8 M, or 10^?9 M) for 24?h, then cells and supernatants were harvested to examine cell viability, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, expression of messenger RNA (mRNA) related to oxidative stress, malondialdehyde (MDA) content and DNA damage. The cell viability was evaluated in mouse Leydig cells by MTT assay, MDA content and SOD, GSH-Px and CAT activities were measured by routine kits, expression of mRNA related to oxidative stress were examined by quantitative real-time polymerase chain reaction (PCR), and DNA damage was investigated by comet assay. Leydig cells treated with T-2 toxin showed significant reductions in cell viability, SOD, GSH-Px and CAT activities, and expression of mRNA related to oxidative stress, and remarkable increases in MDA content and levels of DNA damage. This study proves that T-2 toxin is toxic to Leydig cells of mice. Furthermore, oxidative stress plays an important role in the above-mentioned negative effects of T-2 toxin.     

Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells

T-2 toxin is the most toxic trichothecene and both humans and animals suffer from several pathological conditions after consumption of foodstuffs contaminated with trichothecenes. We investigated the molecular mechanism of T-2 toxin induced cytotoxicity and cell death in HeLa cells. T-2 toxin at LC50 of 10 ng/ml caused time dependent increase in cytotoxicity as assessed by dye uptake, lactatedehydrogenase leakage and MTT assay. The toxin caused generation of reactive oxygen species as early as 30 min followed by significant depletion of glutathione levels and increased lipid peroxidation. The results indicate oxidative stress as underlying mechanism of cytotoxicity. Single stranded DNA damage after T-2 treatment was observed as early as 2 and 4 h by DNA diffusion assay. The cells exhibited apoptotic morphology like condensed chromatin and nuclear fragmentation after 4 h of treatment. Downstream of T-2 induced oxidative stress and DNA damage a time dependent increase in expression level of p53 protein was observed. The increase in Bax/Bcl2 ratio indicated shift in response, in favour of apoptotic process in T-2 toxin treated cells. Western blot analysis showed increase in levels of mitochondrial apoptogenic factors Bax, Bcl-2, cytochrome-c followed by activation of caspases-9, -3 and -7 leading to DNA fragmentation and apoptosis. In addition to caspase-dependent pathway, our results showed involvement of caspase-independent AIF pathway in T-2 induced apoptosis. Broad spectrum caspase inhibitor z-VAD-fmk could partially protect the cells from DNA damage but could not inhibit AIF induced oligonucleosomal DNA fragmentation beyond 4 h. Results of the study clearly show that oxidative stress is the underlying mechanism by which T-2 toxin causes DNA damage and apoptosis.     

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.     

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.     

苹果多酚对脂多糖刺激的RAW264.7细胞COX-2/PGE2和iNOS/NO表达的研究

目的 研究苹果多酚(APE)对脂多糖(LPS)诱发的RAW264.7细胞炎症COX-2/PGE2和iNOS/NO表达的抑制作用.方法 采用APE干预LPS刺激的小鼠单核/巨噬细胞RAW264.7,然后用Griess Reagent法和ELISA法检测细胞分泌的一氧化氮(NO)和前列腺素E2(PGE2)的水平,并且采用RT-qPCR和Western blotting技术检测APE对诱导型一氧化氮合酶(iNOS)和环氧化酶-2(COX-2)水平的影响以及核转录因子(NF-κB)的蛋白表达.结果 APE能显著抑制LPS刺激的RAW264.7细胞中NO、PGE2的含量,下调iNOS及COX-2的表达及NF-κB的磷酸化.结论 APE通过下调NF-κB的活性及iNOS与COX-2表达而发挥抗炎作用.     

Cigarette smoke extracts induce apoptosis in Raw264.7 cells via endoplasmic reticulum stress and the intracellular Ca2+/P38/STAT1 pathway

Cigarette smoke (CS) exposure is a risk factor for chronic obstructive pulmonary disease (COPD). CS exposure impairs the ability of killing pathogens in macrophages, which might be due to the abnormal apoptosis induced by CS. This study explored the effects and mechanisms of cigarette smoke extract (CSE) on the apoptosis of macrophages in vitro. Raw264.7 cells were treated with CSE at different concentrations, and viability and apoptosis of cells was accessed. The protein expression was detected by western blot. The intracellular Ca²⁺ level was evaluated by Fluo-4 AM probe assay.CSE induced the apoptosis and increased the expression of cleaved caspase 3, which were attenuated by a caspase inhibitor. CSE increased the expression of CHOP, BiP and P-eif2α, and the inhibitor of endoplasmic reticulum stress (ERS) decreased the apoptosis induced by CSE. Phosphorylation levels of P38, JNK and ERK1/2 were increased following incubation with CSE. Only P38 inhibitor significantly reduced apoptosis induced by CSE, while ERK1/2 inhibitor promoted apoptosis. Phosphorylation of STAT1 at Ser727 was activated by CSE and attenuated by the P38 inhibitor. Finally, CSE increased the level of intracellular Ca²⁺, and calcium chelator partly attenuated the apoptosis and phosphorylation of P38 and STAT1 induced by CSE.CSE induced a caspase 3-dependent apoptosis in Raw264.7 cells via ERS and intracellular Ca²⁺/P38/STAT1 pathway.