Interactions between cadherin-11 and platelet-derived growth factor receptor-alpha signaling link cell adhesion and proliferation

Cadherins are homophilic cell-to-cell adhesion molecules that help cells respond to environmental changes. Newly formed cadherin junctions are associated with increased cell phosphorylation, but the pathways driving this signaling response are largely unknown. Since cadherins have no intrinsic signaling activity, this phosphorylation must occur through interactions with other signaling molecules. We previously reported that cadherin-11 engagement activates joint synovial fibroblasts, promoting inflammatory and degradative pathways important in rheumatoid arthritis (RA) pathogenesis. Our objective in this study was to discover interacting partners that mediate cadherin-11 signaling. Protein array screening showed that cadherin-11 extracellular binding domains linked to an Fc domain (cad11Fc) induced platelet-derived growth factor (PDGFR)-α phosphorylation in synovial fibroblasts and glioblastoma cells. PDGFRs are growth factor receptor tyrosine kinases that promote cell proliferation, survival, and migration in mesodermally derived cells. Increased PDGFR activity is implicated in RA pathology and associates with poor prognosis in several cancers, including sarcoma and glioblastoma. PDGFRα activation by cadherin-11 signaling promoted fibroblast proliferation, a signaling pathway independent from cadherin-11-stimulated IL-6 or matrix metalloproteinase (MMP)-3 release. PDGFRα phosphorylation mediated most of the cad11Fc-induced phosphatidyl-3-kinase (PI3K)/Akt activation, but only part of the mitogen-activated protein kinase (MAPK) response. PDGFRα-dependent signaling did not require cell cadherin-11 expression. Rather, cad11Fc immunoprecipitated PDGFRα, indicating a direct interaction between cadherin-11 and PDGFRα extracellular domains. This study is the first to report an interaction between cadherin-11 and PDGFRα and adds to our growing understanding that cadherin-growth factor receptor interactions help balance the interplay between tissue growth and adhesion.     

CircPUM1 promotes the malignant behavior of lung adenocarcinoma by regulating miR-326

CircRNAs are reported to be implicated in the development of lung cancer. This study focused on assessing the expression, functions and molecular mechanism of circPUM1 in lung adenocarcinoma. Here, it showed that circPUM1 is significantly upregulated in both lung adenocarcinoma cell lines and tissues. Furthermore, silencing of circPUM1 impaired the proliferation, migration and invasion ability, and increased apoptosis in A549?cells. Nevertheless, overexpression of circPUM1 in SPC-A1 cells has the opposite effect. Silencing of circPUM1 inhibits the tumorigenesis in nude mice. Mechanistically, circPUM1 could sponge miR-326 and promote the expression of its downstream proteins Cyclin D1 and Bcl-2. In summary, this present study revealed that circPUM1 functions as an oncogene to promote the tumorigenesis of lung adenocarcinoma through circPUM1/miR-326/Cyclin D1 and Bcl-2 axis. This indicates that circPUM1 may act as a potential therapeutic target for lung adenocarcinoma.     

模拟失重对白假丝酵母菌增殖和毒性的影响

【背景】近年来研究发现,失重条件可对一些致病微生物的增殖和毒性产生影响,白假丝酵母菌(Candida albicans)是典型的条件性致病真菌,在太空环境和人体中普遍存在,研究失重条件下白假丝酵母菌的增殖和毒性意义重大。【目的】利用旋转细胞培养系统(Rotary cell culture system,RCCS)模拟失重环境对白假丝酵母菌进行连续传代培养,检测模拟失重环境对白假丝酵母菌增殖情况、毒性以及基因表达的变化。【方法】将白假丝酵母菌接种在旋转生物反应器(High aspect rotating vessel,HARV)中,利用旋转细胞培养系统连续传代培养14 d,然后对菌株进行增殖速率测定、不同pH条件下增殖能力测定、生物膜相对形成能力测定和细胞毒性和动物毒力测定;利用转录组测序技术找出差异表达基因,结合性状分析模拟失重可能对白假丝酵母菌增殖和毒力的影响。【结果】与对照组相比,模拟失重组白假丝酵母菌对数期提前,增殖速率加快,在适宜pH条件下的增殖能力普遍提高,但其生物膜形成能力相对减弱,对LoVo细胞和小鼠的毒性减弱;转录组测序发现,模拟失重组共有280个基因表达差异达1.5倍以上(P0.05),其中248个上调、32个下调。差异基因经基因功能注释(Gene ontology,GO)和京都基因及基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)富集分析发现,相关胞膜形成及细胞分裂基因表达上调,生物膜形成、细胞黏附及共生粘连宿主基因表达下调。【结论】模拟失重环境可引起白假丝酵母菌增殖和毒性水平发生变化,相关改变可为研究失重环境对微生物的影响提供参考。     

Expression and functional analysis of flotillins in Dugesia japonica

FLOTILLIN-1 and FLOTILLIN-2 are membrane rafts associated proteins that have been implicated in insulin and growth factor signaling, endocytosis, cell migration, proliferation, differentiation, cytoskeleton remodeling and membrane trafficking. Furthermore, FLOTILLINs also play important roles in the progression of cancer and neurodegenerative diseases. In this study, the roles of flotillins are investigated in planarian Dugesia japonica. The results show that Djflotillin-1 and Djflotillin-2 play a key role in homeostasis maintenance and regeneration process by regulating the proliferation of the neoblast cells, they are not involved in the maintenance and regeneration of the central nervous system in planarians.     

Autophagy protects against redox-active trace metal-induced cell death in rabbit synovial fibroblasts through Toll-like receptor 4 activation

Reactive oxygen species (ROS) are implicated to play a role in initiating rheumatoid arthritis (RA) pathogenesis. We have investigated the mechanism(s) by which essential redox-active trace metals (RATM) may induce cell proliferation and cell death in rabbit synovial fibroblasts. These fibroblast-like synovial (FLS) cells, which express Toll-like receptor 4 (TLR4), were used as a model system that plays a role in potentially initiating RA through oxidative stress. Potassium peroxychromate (PPC, [Cr⁵⁺]), ferrous chloride (FeCl₂, [Fe²⁺]), and cuprous chloride (CuCl, [Cu⁺]) in the indicated valency states were used as exogenous pro-oxidants that can induce oxidative stress through TLR4 coupled activation that also causes HMGB1 release. We measured the proliferation index (PI) of FLS, and examined the effect of RATM oxidants on apoptosis and autophagy by fluorescence cell-sorting flow cytometry (FC). Cell cycle was analysed by FC and autophagy-related protein expression levels were measured by western blot. Our data showed that as RATM as prooxidants increased intracellular ROS (iROS) that can induce oxidative stress. Whereas iROS increased PI in FLS, these reactive species also protected cells against apoptosis by inducing autophagy. Our results indicate that ROS/TLR4-coupled activation may contribute to the pathogenesis of RA in FLS by induction of autophagy. The signalling pathway by which inflammation and its tissue destructive sequel may occur in RA underlies the need for developing therapeutic agents that can inhibit release of tissue-damaging high mobility group box 1 (HMGB1), cytokines, and possess both trace metal chelating capacity and oxidant scavenging properties in a directed combinatorial therapy for RA.     

脂肪来源细胞体外增殖规律及定向诱导分化研究

脂肪组织由整形外科吸脂术获得(19例,31．5±5．8岁)。酶消化法分离抽吸物中细胞,体外扩增至第10代．测定细胞生长曲线、累计倍增数目,明确其体外生长规律和增殖能力;通过对表面抗原CD29、CD105、CD106、CD166、CD49d、CD34、CD31、3G5等的检测分析脂肪来源细胞的群体组成：分别向软骨、骨、脂肪定向诱导,进一步明确该细胞群体定向分化能力。实验表明,每300ml脂肪抽吸物平均可获得5×10~7个有核细胞,体外扩增10代,平均每代倍增数目为1．59±0．224．累计倍增数目为15．53。流式细胞学及免疫细胞化学检测显示,干细胞相关抗原CD29、CD105、CD106、CD166等表达率均＞60%,但与造血系相关的CD34、CD31表达率也分别达到7．3%、29．2%。ADC向软骨诱导可检测到Ⅱ型胶原表达;向成骨诱导可见矿化结节形成,并可检测到AKP、Osteonectin基因表达;向脂肪诱导可检测到PPARr2、GLU-4、Leptin基因表达,细胞内有脂滴形成。脂肪来源的细胞获得量大,体外增殖能力强,并含有具有多向分化潜能细胞,有可能作为组织构建的种子细胞。     

PARP-1抑制剂3-AB对肝癌细胞增殖及凋亡的影响*

目的:探讨PARP-1抑制剂3-AB对肝癌细胞系MHCC97-H和SMMC7721及正常肝细胞系L02的增殖与凋亡的影响。方法:细胞增殖试验观察不同浓度3-AB对三种不同细胞系细胞的增殖作用。Annexin V荧光探针标记,流式细胞学检查观察不同浓度3-AB对不同细胞系细胞凋亡的影响。结果:当3-AB浓度分别为5 mM、10 mM与20 mM时,与对照组(0 mM)相比,在培养第6天时开始出现增殖明显减慢,出现统计学差异(p0.05),第九天差异明显(p0.05)。随着浓度增加,其对肿瘤细胞系MHCC97-H和SMMC7721细胞增殖的抑制程度增加,细胞数均逐渐减少;而同样浓度梯度3-AB对人类肝细胞系L02生长则无明显的抑制作用。进一步实验发现,当3-AB浓度为5mM、10 mM与20 mM时,均可诱导肝癌细胞株MHCC97-H和SMMC7721凋亡,与对照组(0 mM)比较均有统计学差异(p0.05),且细胞凋亡率与3-AB的药物浓度相关:浓度越高,凋亡越明显。而同等浓度3-AB对肝脏细胞系L02无明显的促进凋亡作用。结论:3-AB可以抑制肝癌肿瘤细胞的增殖,促进肿瘤细胞的凋亡,对正常肝脏细胞无明显毒害作用,具有治疗肝癌的的潜在应用价值。     

Potassium chloride released from contracting skeletal muscle may stimulate development of its hypertrophy

The effects of potassium chloride on the expression of IGF-1 splice forms and myoblast proliferation were investigated. KCl at the concentrations of 7–12 mM stimulated the synthesis of IGF-1 and mechano growth factor (MGF) in murine myoblasts as well as in myotubes both at the mRNA and protein levels. Pan-calcium channel blocker CdCl₂ completely abolished stimulation of growth factor expression, whereas blocker of HCN and Na_v1.4 channels ZD7288 drastically reduced it. In addition, potassium chloride stimulated myoblast proliferation, while IGF-1 autocrine signaling inhibition partially suppressed these mitogenic effects.     

Overexpression of miR-493-3p suppresses ovarian cancer cell proliferation,migration and invasion through downregulating DPY30

Accumulating evidence has verified that the aberrant expression level of miR-493?3p is often associated with the occurrence of numerous cancers. Nevertheless, the expression level and effect of this microRNA in ovarian cancer (OC) remain largely unclear. Therefore, the molecular function of miR-493?3p in OC progression was systematically investigated in this study.The expression of miR-493?3p and DPY30 was assessed by qRT-PCR. The protein expression level of DPY30 in cell lines was further assessed by western blot. Cell viability was respectively examined in vitro functional experiments including CCK-8 assay, EdU assay, wound healing assay, colony formation and apoptosis assays as well as the scratch test and transwell assay. Bioinformatics analysis and luciferase reporter assays were performed to predict and clarity of the correlation between miR-493?3p and DPY30.The expression of miR-493?3p was significantly reduced in OC tissues and cells. Functional experimental results showed that miR-493?3p suppressed cellular proliferation, migration, invasion, but promoted apoptosis in OC cells. Mechanistically, we also confirmed that DPY30 could be directly targeted by miR-493?3p based on bioinformatics and dual-luciferase reporter analysis. Rescue experiments results indicated that the inhibitory effect of miR-493?3p on cellular proliferation, migration and invasion and the promotive effect of miR-493?3p on apoptosis was abolished by DPY30 overexpression.Our findings demonstrated the antitumor effect of miR-493?3p through targeting DPY30 in ovarian cancer, indicating that miR-493?3p might represent a promising target for ovarian cancer diagnosis and treatment.