人参皂苷Rh2通过调控GSK-3β/Wnt双信号通路影响骨肉瘤细胞增殖和凋亡

目的：探讨人参皂苷Rh2（Rh2）对骨肉瘤细胞增殖、凋亡、迁移和侵袭的影响,并进一步研究Rh2在骨肉瘤中抗肿瘤作用的机制。方法：分别以不同浓度的Rh2 处理骨肉瘤细胞,用MTT法检测骨肉瘤细胞活性的变化;用基质凝胶（Matrigel）侵袭和孔膜法（Transwell）迁移实验检测骨肉瘤细胞的侵袭和迁移能力的变化;用Annexin V-FITC/PI调亡检测试剂盒及流式细胞仪检测骨肉瘤细胞的调亡变化;用Western blot法检测细胞侵袭、凋亡相关蛋白的表达情况。结果：骨肉瘤细胞经过不同浓度的Rh2处理后,MTT实验结果表明Rh2在一定浓度范围内可以显著抑制骨肉瘤细胞的生长（P ＜0.05）。Matrigel侵袭和Transwell迁移实验结果表明Rh2可以有效抑制骨肉瘤细胞的侵袭与迁移（P ＜0.05）。Annexinv-FITC/PI凋亡检测试剂盒及流式细胞仪检测结果表明,Rh2可以促进骨肉瘤细胞的凋亡反应（P ＜0.05）。Western blot实验结果则显示Rh2 可以上调Bax、E-cadherin蛋白的表达,并抑制Bcl-2、PARP、MMP2、MMP9 蛋白的表达。Rh2 还可以通过激活GSK-3β并抑制β-catenin、Cyclin D1和C-myc相关蛋白来达到调控骨肉瘤细胞增殖、凋亡、迁移和侵袭反应的作用。结论：Rh2可以抑制骨肉瘤细胞的增殖并诱导其凋亡,这种作用可能是通过激活GSK-3β并抑制Wnt/β-catenin信号通路来实现的。     

基于PAK6和Wnt/β-catenin信号通路的苦参碱对肺癌放疗敏感性的影响研究

目的探究苦参碱对肺癌放疗敏感性的影响和作用机制。方法人非小细胞肺癌A549细胞分为对照组、2 Gy放疗组、4 Gy放疗组、苦参碱组、苦参碱联合2 Gy组、苦参碱联合4 Gy组、甘氨双唑钠联合2 Gy组、甘氨双唑钠联合4 Gy组,通过克隆形成、细胞增殖、细胞凋亡评价苦参碱对A549细胞放疗敏感性的影响;建立裸鼠皮下移植瘤模型,分为对照组、5 Gy放疗组、苦参碱组、苦参碱联合5 Gy组、甘氨双唑钠联合5 Gy组,记录小鼠瘤体积;Western blotting法检测A549细胞和小鼠瘤组织中β-连环蛋白(β-catenin)、p21激活蛋白激酶6(p21-activated protein kinase,PAK6)、c-myc、半胱氨酸蛋白酶3(Caspase-3)的表达。结果与单独放疗组相比,苦参碱联合放疗组A549细胞克隆形成、细胞增殖显著降低(P<0.001),细胞凋亡显著增加(P<0.001),裸鼠肿瘤体积显著降低(P<0.001),细胞和裸鼠肿瘤组织中PAK6、c-myc、磷酸化β-catenin蛋白表达显著下调(P<0.05、0.01、0.001),Caspase-3蛋白表达显著上调(P<0.001)。结论苦参碱通过干扰PAK6表达,抑制Wnt/β-连环蛋白(Wnt/β-catenin)信号通路,从而提高肺癌的放疗敏感性。     

外源性Wnt5a诱导K562细胞分化表型的实验研究

本研究探讨外源性Wnt5a诱导K562细胞定向分化的作用。用重组腺病毒AdWnt5a、AdGFP感染CHO细胞,分别制备Wnt5a和GFP对照条件培养液,并处理K562细胞1-7天,用光学显微镜和电子显微镜观察细胞形态变化;采用过氧化物酶(POX)、糖原(PAS)和非特异性酯酶(α-NAE)染色、细胞表面分化抗原CD13、CD14、CD68鉴定K562细胞的分化表型;用流式细胞术检测细胞分化周期的变化。结果表明:与对照GFP条件培养液相比,Wnt5a条件培养液处理的K562细胞形态和超微结构均出现了分化成熟的特征;POX、PAS、α-NAE细胞化学染色均为阳性,并且α-NAE阳性70%可被氟化钠抑制;单核细胞系表面标志抗原CD14、CD68和粒细胞系表面标志抗原CD13经免疫细胞化学染色均呈阳性,但CD13与对照比较无显著性差异;Wnt5a处理K562细胞5天,细胞周期阻滞在G2期。结论:外源性的Wnt5a可诱导K562细胞向成熟方向分化,并且有向单核细胞系分化的现象。     

金鸡毛草提取物经Wnt/β-catenin信号通路促进大鼠Ⅲ期压疮溃疡愈合的作用研究

目的观察金鸡毛草提取物经Wnt/β-连环蛋白(β-catenin)信号通路促进大鼠Ⅲ期压疮溃疡愈合的作用。方法建立Ⅲ期压疮溃疡大鼠模型,将造模成功的SD大鼠随机分为模型组与金鸡毛草提取物低、中、高(4、8、16 g/kg)剂量组,每组12只。另取12只正常大鼠作为对照组。金鸡毛草提取物低、中、高剂量组大鼠灌胃4、8、16 g/kg的金鸡毛草提取物,灌胃体积10 mL/kg,对照组和模型组大鼠灌胃等体积生理盐水,每天1次,给药周期为2周。给药周期结束后,检测大鼠创面愈合率,酶联免疫吸附试验(ELISA)法测定大鼠血清白细胞介素-2(IL-2)、白细胞介素-4(IL-4)、肿瘤坏死因子-α(TNF-α)水平,苏木素-伊红(HE)染色观察大鼠压疮溃疡组织和正常组织病理变化,实时荧光定量PCR及蛋白免疫印迹法测定大鼠压疮溃疡组织和正常组织中Wnt、β-catenin mRNA和蛋白水平。结果对照组大鼠皮肤组织结构正常,可见大量成纤维细胞及毛细血管;模型组大鼠压疮溃疡组织大量炎症细胞浸润,成纤维细胞及毛细血管数目明显减少,表皮明显变薄;金鸡毛草提取物低、中、高剂量组大鼠压疮溃疡创面组织已经出现结痂,且表皮明显增厚,炎性细胞浸润较轻。与对照组比较,模型组大鼠血清IL-2、IL-4、TNF-α、压疮溃疡组织Wnt、β-catenin mRNA和蛋白水平升高(P <0.05);与模型组比较,金鸡毛草提取物低、中、高剂量组大鼠创面愈合率依次升高,血清IL-2、IL-4、TNF-α、压疮溃疡组织Wnt、β-catenin mRNA和蛋白水平依次降低(P <0.05),呈剂量依赖性(P <0.05)。结论金鸡毛草提取物能加速大鼠Ⅲ期压疮溃疡愈合,减轻大鼠Ⅲ期压疮炎症反应;其机制可能与金鸡毛草提取物可促进大鼠Ⅲ期压疮溃疡组织Wnt、β-catenin mRNA和蛋白的表达进而激活Wnt/β-catenin信号通路有关。     

白皮杉醇对三阴性乳腺癌细胞系MDA-MB-468抗肿瘤作用及机制

目的:考察白皮杉醇(PIC)对三阴性乳腺癌细胞MDA-MB-468增殖、凋亡及细胞周期的作用,并对其作用机制进行探讨。方法:采用噻唑蓝(MTT)比色法考察PIC(0,2.5,5.0,10.0,20.0,40.0,80.0,160.0μmol·L-1)对三阴性乳腺癌MDA-MB-468细胞成活率的影响,并计算半抑制率(IC50);采用碘化丙啶(PI)染色观察PIC(5.0,10.0,20.0μmol·L^-1)对MDA-MB-468细胞周期的影响;采用细胞凋亡检测(Annexin V-FITC/PI)双染法观察PIC(5.0,10.0,20.0μmol·L^-1)对三阴性乳腺癌MDA-MB-468细胞的诱导凋亡作用;采用蛋白免疫印迹法(Western blot)观察不同浓度PIC(5.0,10.0,20.0μmol·L^-1)对MDA-MB-468细胞增殖、凋亡蛋白的影响,并用Western blot对分泌型糖蛋白Wnt/β-连环蛋白(Wnt/β-catenin)信号通路相关蛋白进行检测。结果:MTT比色法结果显示,与空白组比较,PIC(5.0,10.0,20.0,40.0,80.0,160.0μmol·L^-1)可呈浓度依赖性地抑制MDA-MB-468细胞的增殖(P<0.05,P<0.01),IC50为(39.4±4.6)μmol·L^-1;作用48 h,PIC(5.0,10.0,20.0μmol·L^-1)呈浓度依赖性地升高MDA-MB-468细胞处于细胞周期G0/G1期细胞(P<0.01);呈浓度依赖性地诱导MDA-MB-468细胞凋亡(P<0.01),其中,PIC(20.0μmol·L^-1)诱导细胞凋亡率为49.87%;PIC(10.0,20.0μmol·L^-1)可明显降低MDA-MB-468细胞中β-catenin及原癌基因(C-myc),黏附因子(CD44)蛋白的表达水平(P<0.05,P<0.01);PIC(5.0,10.0,20.0μmol·L^-1)可显著抑制蛋白激酶B(Akt)磷酸化,p38丝裂原活化蛋白激酶(p38 MAPK)蛋白的磷酸化,B淋巴细胞瘤-2(Bcl-2)的蛋白表达水平(P<0.01);增强半胱氨酸天冬氨酸蛋白酶-3(Caspase-3),Bcl-2相关X蛋白(Bax)和磷酸化β-catenin的蛋白表达(P<0.01)。结论:PIC可能通过抑制Wnt/β-catenin信号通路抑制MDA-MB-468细胞增殖,并将细胞周期阻滞在G0/G1期,从而诱导其凋亡。     

β-Catenin Preserves the Stem State of Murine Bone Marrow Stromal Cells Through Activation of EZH2

During bone marrow stromal cell (BMSC) differentiation, both Wnt signaling and the development of a rigid cytoskeleton promote commitment to the osteoblastic over adipogenic lineage. β-catenin plays a critical role in the Wnt signaling pathway to facilitate downstream effects on gene expression. We show that β-catenin was additive with cytoskeletal signals to prevent adipogenesis, and β-catenin knockdown promoted adipogenesis even when the actin cytoskeleton was depolymerized. β-catenin also prevented osteoblast commitment in a cytoskeletal-independent manner, with β-catenin knockdown enhancing lineage commitment. Chromatin immunoprecipitation (ChIP)-sequencing demonstrated binding of β-catenin to the promoter of enhancer of zeste homolog 2 (EZH2), a key component of the polycomb repressive complex 2 (PRC2) complex that catalyzes histone methylation. Knockdown of β-catenin reduced EZH2 protein levels and decreased methylated histone 3 (H3K27me3) at osteogenic loci. Further, when EZH2 was inhibited, β-catenin's anti-differentiation effects were lost. These results indicate that regulating EZH2 activity is key to β-catenin's effects on BMSCs to preserve multipotentiality. © 2020 American Society for Bone and Mineral Research.     

Diallyl disulfide inhibits proliferation,epithelial–mesenchymal transition,and invasion through RORα-mediated downregulation of Wnt1/β-catenin pathway in gastric cancer cells

Overactivation of Wnt/β-catenin pathway due to dysfunction of retinoid-related orphan receptor α (RORα) is related to cancer development and progression. Diallyl disulfide (DADS), an active component of garlic, has been reported in our previous study for upregulation of RORα expression in gastric cancer (GC) cells. It remains to be elucidated the role and mechanism of RORα in DADS against GC. This study revealed that DADS treatment resulted in reduced expression levels of Wnt1, β-catenin, TCF-4, intranuclear β-catenin and p-β-catenin in GC cells, concomitant with the compromised expression of β-catenin target genes (Axin, c-Jun, and c-Myc). RORα overexpression augmented DADS-induced downregulation of Wnt1/β-catenin pathway, G2/M phase arrest, and cell growth inhibition in vitro and in vivo. Contrarily, knockdown of RORα attenuated these effects of DADS. Interestingly, DADS induced an increase in the binding of RORα to β-catenin, which may lead to reduction of β-catenin phosphorylation and nuclear translocation. This interplay modulated by DADS may affect β-catenin target gene expression for that the opposite results were observed in DADS-treated RORα knockdown and overexpression cells. DADS caused a decrease in vimentin, snail and MMP-9, as well as an increase in E-cadherin and TIMP3 expression, which restricted epithelial–mesenchymal transition (EMT), migration, and invasion. The aforementioned effects of DADS were weakened simultaneously when the suppression of DADS on the Wnt1/β-catenin pathway was resisted by knockdown of RORα. In contrast, overexpression of RORα enhanced the effects of DADS. Therefore, RORα-mediated downregulation of Wnt1/β-catenin pathway could undertake an important role in anticancer activity of DADS against GC cell proliferation, EMT, migration, and invasion.     

Efficacy of a sclerostin antibody compared to a low dose of PTH on metaphyseal bone healing

We compared the effect of a sclerostin antibody to that of a clinically relevant dose of parathyroid hormone (PTH) in a rat model for metaphyseal bone healing. Screws of steel or poly methyl methacrylate (PMMA) were inserted bilaterally into the proximal tibia of young male rats. During 4 weeks the animals then received injections of either phosphate buffered saline (control), sclerostin antibody (25 mg/kg, twice weekly) or PTH (5 µg/kg, daily). The healing response around the screws was then assessed by mechanical testing and X‐ray microtomography (µCT). To distinguish between effects on healing and general effects on the skeleton, other untraumatized bone sites and serum biomarkers were also assessed. After 4 weeks of treatment, PTH yielded a 48% increase in screw pull‐out force compared to control (p = 0.03), while the antibody had no significant effect. In contrast, the antibody increased femoral cortical and vertebral strength where PTH had no significant effect. µCT showed only slight changes that were statistically significant for the antibody mainly at cortical sites. The results suggest that a relatively low dose of PTH stimulates metaphyseal repair (screw fixation) specifically, whereas the sclerostin antibody has wide‐spread effects, mainly on cortical bone, with less influence on metaphyseal healing. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:471–476, 2014.     

Secreted Wnt Antagonists During Eradication of Cytomegalovirus Infection in Solid Organ Transplant Recipients

We evaluated secreted wingless (Wnt) modulators during cytomegalovirus (CMV) infection in solid organ transplant recipients (SOTr). The major findings were: (i) Plasma levels of Dickkopf‐1 (DKK‐1) were significantly lower in patients with CMV DNAemia above lower level of quantification at baseline. (ii) Receiver operating characteristic analysis indicated that low DKK‐1 and increased secreted frizzled related protein‐3 levels were predictors of poor virological outcomes during follow‐up. Our findings demonstrate an imbalanced pattern of circulating secreted Wnt modulators in SOTr with poor virological outcomes following treatment for CMV disease, and may suggest a role for dysregulated Wnt signaling on viral pathogenesis during CMV infection.