具核梭杆菌通过调节肠道代谢产物丁酸钠上调Cdk1促进结直肠癌发展

该文探讨了肠道微生物具核梭杆菌(Fusobacterium nucleatum,Fn)通过调节代谢产物丁酸钠(NaB)对结直肠癌(CRC)发生发展的影响及其分子机制。提取临床组织RNA和蛋白,RT-qPCR和Western blot检测肿瘤组织与正常/癌旁组织Cdk1的mRNA及蛋白表达,同时检测具核梭杆菌的mRNA的相对水平,并分析其与Cdk1的相关性。具核梭杆菌处理结直肠癌细胞24 h后检测周期相关蛋白Cdk1和P21的表达水平,核磁共振检测培养基上清差异代谢物。不同浓度差异代谢物NaB处理结直肠癌细胞DLD-1、SW480、HCT116,使用MTT和克隆形成实验检测DLD-1、SW480、HCT116增殖能力。流式细胞术检测NaB对结直肠癌细胞SW480周期阻滞位点,Western blot检测周期相关蛋白Cdk1、P21、C-myc的表达水平。流式细胞术检测NaB处理后结直肠癌细胞SW480凋亡率变化情况,Western blot检测凋亡相关蛋白Cleaved-Casepase3、Cleaved-PARP、Bcl-2的表达水平。采用MTT实验检测不同MOI具核梭杆菌作用结直肠癌细胞4、8、24 h后对其增殖能力的影响。将结直肠癌细胞与具核梭杆菌共培养24 h,Western blot检测相关蛋白Cdk1、c-myc、Cleaved-Caspase3的表达情况。结果显示,在肿瘤组织中Cdk1蛋白水平和mRNA水平均明显高于正常/癌旁组织(P0.05),并且Cdk1与具核梭杆菌mRNA表达水平存在一定相关性。具核梭杆菌处理结直肠癌细胞DLD-1和HCT116后,Western blot结果显示Cdk1和P21蛋白水平上升。核磁共振结果表明,菌处理组代谢模式与未处理组存在明显差异,主要代谢物NaB相对含量明显低于未处理组(P0.01)。使用1 mmol/L NaB处理结直肠癌细胞系DLD-1、SW480、HCT116 24 h后,细胞生存率分别为(89.18±1.92)%、(85.07±0.61)%、(83.59±2.18)%,且随着药物浓度升高,药物对细胞活性的抑制率逐步上升。同时,经1 mmol/L NaB处理后,DLD-1、HCT116和SW480细胞的克隆形成率相比于对照分别下降了(20.07±4.85)%、(36.47±5.31)%、(31.13±5.22)%。流式检测细胞周期显示,NaB引起结直肠癌细胞S期阻滞。NaB处理结直肠癌细胞24 h后,周期相关蛋白P21表达水平上升,Cdk1、C-myc蛋白表达水平下降(P0.05)。流式检测细胞凋亡显示,NaB引起结直肠癌细胞SW480凋亡增加。NaB处理结直肠癌细胞24 h后,凋亡相关蛋白Cleaved-Casepase3、Cleaved-PARP表达水平上升,抗凋亡蛋白Bcl-2表达水平下降。MOI=50的具核梭杆菌分别处理结直肠癌细胞SW480、HCT116 4 h后,细胞增殖率分别增加了(4.45±0.25)%、(2.61±0.75)%;并且随着具核梭杆菌MOI的增加和处理时间的延长,结直肠癌细胞的增殖率逐渐上升。将SW480细胞与HCT116细胞与具核梭杆菌共培养24 h,Western blot结果显示,具核梭杆菌感染促进了周期相关蛋白Cdk1、C-myc的表达,而其与NaB共同处理时则大大减弱了这一作用;NaB诱导Caspase3的剪切,导致Cleaved-Caspase3表达增加,而具核梭杆菌感染则减弱了这一作用。综上所述,肠道微生物具核梭杆菌通过调节肠道代谢物NaB上调Cdk1,促进结直肠癌细胞增殖,抑制结直肠癌细胞凋亡,进而影响结直肠癌的发生发展。     

丁酸梭菌抑制Cdk2表达经Wnt/βcatenin 信号通路调控结直肠癌细胞迁移

目的研究丁酸梭菌(Clostridium butyricum,C. butyricum)与细胞周期蛋白激酶2(Cdk2)对结直肠癌细胞迁移的作用,探讨其作用机制。方法以结直肠癌细胞DLD1作为研究载体,运用蛋白印迹法(Western blot)、MTT、定量聚合酶链反应(qPCR)、Transwell和划痕实验等研究C. butyricum和Cdk2对结直肠癌形成的影响。结果Western blot和qPCR结果显示,癌组织Cdk2阳性表达率明显高于癌旁组织(t=8.271,P<0.01)。qPCR结果表明C. butyricum在结直肠癌患者粪便中的丰度明显低于正常人群(t=6.903,P<0.05)。MTT、Transwell和划痕实验表明,C. butyricum培养上清作用的结直肠癌细胞生长速度明显低于对照组(MTT:96 h t=4.356,P<0.05; 120 h t=6.025,P<0.05。Transwell:C. butyricum t=3.794,P<0.05; Cdk2 knockdown t=5.086,P<0.01;丁酸梭菌+Cdk2 knockdown t=4.815,P<0.01。划痕:24 h t=4.356,P<0.01; 48 h t=6.025,P<0.01),且C. butyricum通过Cdk2抑制了结直肠癌细胞增殖与迁移能力。Western blot结果显示C. butyricum抑制Cdk2的表达,且与Cdk2协同作用调控Wnt/βcatenin信号通路。结论C. butyricum通过抑制Cdk2经Wnt/βcatenin信号通路调控结直肠癌细胞的增殖和迁移。     

酿酒酵母Cdk1抑制蛋白的研究进展

细胞周期蛋白依赖性激酶1(cyclin-dependent kinase 1,Cdk1)是真核生物细胞周期调控的核心,也是维持基因组稳定性的重要激酶,其活性受到严格调控.CDK抑制蛋白(cyclin-dependent kinase inhibitor,CKI)是调节其活性的一类关键负调控因子,CKI功能失活导致细胞不受控制地增殖,促进癌症的发生发展.酿酒酵母作为细胞周期研究的重要模式生物,在揭示CDK活性调控机制中发挥着重要作用.酿酒酵母中已发现的Cdk1抑制蛋白CKI包括Far1、Sic1以及最近鉴定的Cip1蛋白.这三个CKI蛋白在不同细胞时期中,通过抑制Cdk1活性调控细胞周期的进程.此外,CKI还在应对环境胁迫,保持基因组稳定性中发挥重要作用.本文对酿酒酵母Cdk1抑制蛋白CKI的研究进展,尤其是CKI在细胞周期运转及胁迫应答中的作用做出综述,以期为细胞周期及癌症的基础研究提供模式依据.     

Cyclin D1与细胞周期调控

细胞周期是细胞生命活动中一个最重要的过程,其关键是G1 期的启动.细胞周期蛋白(Cyclin)、细胞周期蛋白依赖性激酶(CDKs)和CDK抑制因子(CKIs)是参与钿胞周期调控的主要因子.Cyclin D1是调控细胞周期G1期的关键蛋白,是一个比其他Cyclins更加敏感的指标,对细胞周期调控至关重要.综述Cyclin D1的结构和功能及其在肿瘤组织中的表达特征,初步分析Cyclin D在昆虫细胞周期调控的研究.     

Cdk1在浆液性卵巢癌中的表达及其与化疗耐药及预后的相关性

目的:卵巢癌是女性生殖致死率最高的恶性肿瘤。Cdk1作为细胞周期依赖性激酶中的核心分子,对肿瘤细胞的发生发展具有重要作用。本文旨在探讨Cdk1蛋白在上皮性浆液性卵巢癌中的表达情况,并分析其表达水平与患者临床病理特征、化疗反应及预后之间的关系。方法:采用免疫组化法检测68例浆液性卵巢癌中Cdk1蛋白的表达情况,并结合临床资料分析Cdk1蛋白的表达水平在浆液性卵巢癌患者中的意义。结果:Cdk1在浆液性卵巢癌患者中具有不同程度的阳性表达,其表达水平和患者的年龄、病理分化程度、淋巴结转移情况及临床分期无明显相关性(P0.05),但是其高表达与化疗耐药明显相关(P=0.040)。化疗耐药的卵巢癌患者中Cdk1的蛋白表达明显高于化疗敏感组,并且生存分析发现,高表达Cdk1的患者预后较差。结论:本研究证明Cdk1在浆液性卵巢癌中有较高表达,并且Cdk1的表达与卵巢癌化疗后复发有关,高的Cdk1表达预示着较差的预后。Cdk1可能是晚期浆液性卵巢癌治疗的新靶点。     

具核梭杆菌协同Cdk5促进结直肠癌细胞迁移

目的以结直肠癌细胞SW480作为研究载体,分析具核梭杆菌(F.nucleatum)对Cdk5和STAT3途径相关基因及其炎症因子表达的影响,阐明F.nucleatum协同Cdk5促进结直肠癌形成和发展的分子机制。方法以结直肠癌细胞SW480作为研究载体,运用Western Blotting、qPCR、免疫组化和细胞划痕等实验研究F.nucleatum和Cdk5对结直肠癌形成的影响。结果免疫组化结果显示,癌组织Cdk5阳性表达率明显高于癌旁组织(t=8.218,P0.01)。细胞划痕实验结果表明,F.nucleatum菌液作用的结直肠癌细胞迁移率明显高于对照组(24 h:t=5.868,P0.01; 48 h:t=6.941,P0.01)。Western Blotting结果显示,F.nucleatum协同Cdk5可能通过STAT3通路调控结直肠癌细胞凋亡。qPCR结果显示,F.nucleatum菌液作用的结直肠癌细胞的炎症因子表达明显高于对照组(IL-6:t=5.542,P0.05; COX2:t=16.893,P0.01; TNF-α:t=16.963,P0.01; IL-8:t=3.733,P0.01)。结论 F.nucleatum协同Cdk5促进了结直肠癌细胞的迁移。     

细胞周期依赖性激酶4(Cdk4)在肿瘤发生发展中的作用

细胞周期依赖性激酶4(cdk4)是丝氨酸/苏氨酸激酶家族的成员,调控细胞周期G1期的进程.Cdk4与周期蛋白D(cyclin D)结合形成复合物,在G1期的演进中起重要作用,一旦出现失调就可能导致癌症的发生,并且也有一系列的内在和外在的信号调控着这个复合物.Cdk4以及它的调控因子在肿瘤的发生和转移中都显示了重要的作用.     

调控胞质分裂的中心体相关蛋白Cep55

中心体是哺乳动物细胞内的微管组织中心,参与纺锤体的装配,因此在胞质分裂中起重要调控作用。最新发现的中心体相关蛋白Cep55(centrosomal protein,55kD)属于卷曲螺旋(coiled-coil)蛋白质家族成员,其基因定位于人染色体10q23.33。该蛋白质在多种正常组织及肿瘤细胞中均有表达,与细胞周期中的中心体和中间体偶联,被Erk2、Cdk1及Plk1共同磷酸化后发挥细胞周期调控作用。其研究对细胞周期的调控及对肿瘤发生的认识将产生极其重要的意义。     

CCNB2在结直肠癌中的表达及临床意义

目的:探讨细胞周期蛋白B2(Cyclin B2,CCNB2)在结直肠癌组织中的表达及其临床意义。方法:选择45对结直肠癌组织及癌旁正常结直肠组织样本,分别采用实时定量PCR(qRT-PCR)方法和免疫组织化学技术检测CCNB2的mRNA和蛋白表达,并进一步分析CCNB2的表达与结直肠癌临床病理特征之间的关系。结果:结直肠癌组织中CCNB2 mRNA的表达显著高于癌旁正常结直肠组织,差异有统计学意义(P0.001),且CCNB2的mRNA表达与结直肠癌的肿瘤大小、浸润深度及TNM分期显著相关(P0.05),与年龄、性别、肿瘤位置、分化程度、脉管神经浸润、淋巴结转移和远处转移均无关(P0.05)。45例结直肠癌标本中39例表达(+~+++),6例表达(-)。CCNB2蛋白主要表达于结直肠癌细胞质中,少量见于细胞核。结直肠癌组织中CCNB2蛋白的阳性表达率为86.7%,显著高于癌旁正常结直肠组织,并与患者的性别、年龄、分化程度和肿瘤转移均无显著相关性(P0.05),但与肿瘤分期、浸润程度均显著相关(P0.05)。结论:CCNB2在结直肠癌中呈异常高表达,且与结直肠癌的发生发展相关,有望作为结直肠癌的诊断和预后预测参考指标。     

抑制eIF3I蛋白的泛素化降解促进人宫颈癌细胞增殖

目的:研究eIF3I蛋白在细胞中的泛素化修饰,阐明其对人宫颈癌细胞系Hela增殖的影响.方法:通过点突变技术获得突变体K282R,与野生型eIF3I比较泛素化的水平,研究细胞内的泛素化修饰调控.经流式细胞仪分析细胞周期,研究野生型蛋白eIF3I和突变体K282R对Hela细胞的细胞周期影响.再从周期蛋白水平研究eIF3I对细胞增殖的调控作用.结果:突变体K282R比野生型eIF3I蛋白的外源表达量大.在Hela细胞中K282R突变体的泛素化水平低,抑制了该蛋白的泛素-蛋白酶体途径降解.过表达eIF3I能上调周期蛋白Cyclin D1的表达量,促进细胞进入由G1期进入S期.同时,泛素化程度低的突变体K282R具有较强的促进细胞增殖的作用.结论:抑制eIF3I的泛素-蛋白酶体途径降解能上调周期蛋白CyclinD1的表达,促进肿瘤细胞增殖,提示eIF3I在细胞增殖和肿瘤发生发展中发挥作用.     

Cyclin B1 Suppresses Colorectal Cancer Invasion and Metastasis by Regulating E-Cadherin

Cyclin B1, a mitotic cyclin, has been implicated in malignances. However, its contribution to colorectal cancer invasion and metastasis are still not well understood. Here, we demonstrated that the invasion and metastasis of colorectal cancer is regulated by Cyclin B1. Overexpression of Cyclin B1 was observed in colorectal cancer tissues, but this elevated expression was negatively associated with lymph node metastasis, distant metastasis stage, and TNM stage. The Kaplan-Meier survival analysis proved that low Cyclin B1 expression was associated with poor overall survival of patients with colorectal cancer. Inhibition of Cyclin B1 in colorectal cancer cells enhanced the cell migration and invasion of three different colorectal cancer cell lines. In studying the possible mechanism by which Cyclin B1 suppresses colorectal cancer invasion and metastasis, we observed that suppression of Cyclin B1 decreased the expression of E-cadherin protein level. Our findings suggest that Cyclin B1 could suppress the invasion and metastasis of colorectal cancer cells through regulating E-cadherin expression, which enables the development of potential intervention strategies for colorectal cancer.     

Cyclin gene expression and growth control in normal and neoplastic human breast epithelium

Recent advances in defining the molecular mechanisms of cell cycle control in eukaryotes provide a basis for beter understanding the hormonal control of cell proliferation in normal and neoplastic breast epithelium. It is now clear that a number of critical steps in cell cycle progression are controlled by families of serine/threonine kinases, the cdks. These kinases are activated by interactions with various cyclin gene products which form the regulatory subunits of the kinase complexes. Several families of cyclins control cell cycle progression in G₁ phase, cyclins C, D and E, or in S, G₂ and mitosis, cyclins A and B. Recent studies have defined the expression and regulation of cyclin genes in normal breast epithelial cells and in breast cancer cell lines. Following growth arrest of T-47D breast cancer cells by serum deprivation restimulation with insulin results in sequential induction of cyclin genes. Cyclin D1 mRNA increases within 1 h of mitogenic stimulation and is followed by increased expression of cyclins D3 and E in G₁ phase, cyclin A in late G₁/early S phase and cyclin B1 in G₂. Similar results were observed following epidermal growth factor stimulation of normal breast epithelial cells. Other hormones—oestrogens and progestins—and growth factors—insulin-like investigated for their effects on G₁ cyclin gene expression. In all cases there was an excellent correlation between the induction of cyclin D1 mRNA and subsequent entry into S phase. Furthermore, growth inhibition by antioestrogens and concurrent G₁ arrest were preceded by an acute decrease in cyclin D1 gene expression. These observations suggest a likely role for cyclin D1 in mediating many of the known hormonal effects on cell proliferation in breast epithelial cells.     

LIN-9 Phosphorylation on Threonine-96 Is Required for Transcriptional Activation of LIN-9 Target Genes and Promotes Cell Cycle Progression

Cell cycle transitions are governed by the timely expression of cyclins, the activating subunits of Cyclin-dependent kinases (Cdks), which are responsible for the inactivation of the pocket proteins. Overexpression of cyclins promotes cell proliferation and cancer. Therefore, it is important to understand the mechanisms by which cyclins regulate the expression of cell cycle promoting genes including subsequent cyclins. LIN-9 and the pocket proteins p107 and p130 are members of the DREAM complex that in G0 represses cell cycle genes. Interestingly, little is know about the regulation and function of LIN-9 after phosphorylation of p107,p130 by Cyclin D/Cdk4 disassembles the DREAM complex in early G1. In this report, we demonstrate that cyclin E1/Cdk3 phosphorylates LIN-9 on Thr-96. Mutating Thr-96 to alanine inhibits activation of cyclins A2 and B1 promoters, whereas a phosphomimetic Asp mutant strongly activates their promoters and triggers accelerated entry into G2/M phase in 293T cells. Taken together, our data suggest a novel role for cyclin E1 beyond G1/S and into S/G2 phase, most likely by inducing the expression of subsequent cyclins A2 and B1 through LIN-9.     

特异性蛋白1(SP1)上调FOXP4-AS1促进结直肠癌细胞增殖

大量的证据表明,长链非编码RNAs (long non-coding RNAs)在结直肠癌发生发展中发挥重要作用。有迹象表明,lncRNA FOXP4-AS1推动结直肠癌的进程。本文通过数据库信息分析发现,FOXP4-AS1在结直肠癌中高表达且与患者较差的预后正相关。实时荧光定量PCR方法也证实,FOXP4-AS1在结直肠癌细胞和组织中的表达量均高于正常细胞和组织。其中,FOXP4-AS1在结肠癌细胞LOVO中表达量最高,是正常结直肠细胞的13倍。生物信息学预测结合双荧光素酶报告基因实验和染色质沉淀研究结果表明,特异性蛋白1（specificity protein 1,SP1）可直接结合在FOXP4-AS1启动子上,上调其活性。过表达FOXP4-AS1,可下调p16和p18表达,同时上调CDK4、CDK6和细胞周期蛋白 D1表达,最终促进结直肠癌细胞增殖。相反,敲低FOXP4-AS1将上调p16和p18表达,抑制CDK4、CDK6和细胞周期蛋白 D1,获得相反的结果。总之,特异性蛋白1(SP1)上调FOXP4-AS1,促进结直肠癌细胞增殖。     

Cyclin D3 expression in melanoma cells is regulated by adhesion-dependent phosphatidylinositol 3-kinase signaling and contributes to G1-S progression

D-type cyclins regulate G1 cell cycle progression by enhancing the activities of cyclin-dependent kinases (CDKs), and their expression is frequently altered in malignant cells. We and others have previously shown that cyclin D1 is up-regulated in melanoma cells through adhesion-independent MEK-ERK1/2 signaling initiated by mutant B-RAF. Here, we describe the regulation and role of cyclin D3 in human melanoma cells. Cyclin D3 expression was enhanced in a cell panel of human melanoma cell lines compared with melanocytes and was regulated by fibronectin-mediated phosphatidylinositol 3-kinase/Akt signaling but not MEK activity. RNA interference experiments demonstrated that cyclin D3 contributed to G1-S cell cycle progression and proliferation in melanoma cells. Overexpression of cyclin D1 did not recover the effects of cyclin D3 knockdown. Finally, immunoprecipitation studies showed that CDK6 is a major binding partner for cyclin D3, whereas CDK4 preferentially associated with cyclin D1. Together, these findings demonstrate that cyclin D3 is an important regulator of melanoma G1-S cell cycle progression and that D-type cyclins are differentially regulated in melanoma cells.     

Involvement of the D-type cyclins in germ cell proliferation and differentiation in the mouse

Using immunohistochemistry, the expression of the D-type cyclin proteins was studied in the developing and adult mouse testis. Both during testicular development and in adult testis, cyclin D(1) is expressed only in proliferating gonocytes and spermatogonia, indicating a role for cyclin D(1) in spermatogonial proliferation, in particular during the G(1)/S phase transition. Cyclin D(2) is first expressed at the start of spermatogenesis when gonocytes produce A(1) spermatogonia. In the adult testis, cyclin D(2) is expressed in spermatogonia around stage VIII of the seminiferous epithelium when A(al) spermatogonia differentiate into A(1) spermatogonia and also in spermatocytes and spermatids. To further elucidate the role of cyclin D(2) during spermatogenesis, cyclin D(2) expression was studied in vitamin A-deficient testis. Cyclin D(2) was not expressed in the undifferentiated A spermatogonia in vitamin A-deficient testis but was strongly induced in these cells after the induction of differentiation of most of these cells into A(1) spermatogonia by administration of retinoic acid. Overall, cyclin D(2) seems to play a role at the crucial differentiation step of undifferentiated spermatogonia into A(1) spermatogonia. Cyclin D(3) is expressed in both proliferating and quiescent gonocytes during testis development. Cyclin D(3) expression was found in terminally differentiated Sertoli cells, in Leydig cells, and in spermatogonia in adult testis. Hence, although cyclin D(3) may control G(1)/S transition in spermatogonia, it probably has a different role in Sertoli and Leydig cells. In conclusion, the three D-type cyclins are differentially expressed during spermatogenesis. In spermatogonia, cyclins D(1) and D(3) seem to be involved in cell cycle regulation, whereas cyclin D(2) likely has a role in spermatogonial differentiation.