The role of ubiquitination and deubiquitination in tumor invasion and metastasis

Ubiquitination is vital for multiple cellular processes via dynamic modulation of proteins related to cell growth, proliferation, and survival. Of the ubiquitination system components, E3 ubiquitin ligases and deubiquitinases have the most prominent roles in modulating tumor metastasis. This review will briefly summarize the observations and underlying mechanisms of multiple E3 ubiquitin ligases and deubiquitinases to regulate tumor metastasis. Further, we will discuss the relationship and importance between ubiquitination components and tumor progression.     

FOXG1在结直肠癌侵袭及转移中的作用及机制

构建叉头框G1(Forkhead box G1,FOXG1)的慢病毒干扰(shRNA)质粒及表达质粒,通过敲低和过表达FOXG1探讨其对结直肠癌细胞上皮-间质转化EMT的作用及其机制。应用Western blotting检测FOXG1在RKO、SW480、SW620、LOVO、DLD-1五种结直肠癌细胞中蛋白的表达水平,设计并合成FOXG1的shRNA片段(shFOXG1),运用DNA重组技术获得重组质粒,经双酶切技术及测序方法鉴定后进行慢病毒的包装、纯化及稳定转染,经筛选后获得稳定的结直肠癌细胞株,通过Western blotting和qRT-PCR技术检测FOXG1敲低和过表达效率及EMT关键因子E-cadherin、Vimentin、Fibronectin、Snail、Twist mRNA和蛋白的变化,光学显微镜观察敲低后细胞形态学变化,通过划痕实验检测迁移能力变化,Transwell检测侵袭迁移能力的变化。5种结直肠癌细胞中,FOXG1在RKO细胞中蛋白表达量最高,而在DLD-1细胞中表达量最低,与对照组相比较,在RKO细胞中敲低FOXG1,细胞形态由长梭型变成了类圆形或者多边形,细胞极性和紧密连接增加,细胞迁移距离明显降低,侵袭转移穿过小室的细胞数也明显减少,EMT关键因子E-cadherin表达增高,Vimentin、Fibronectin、Snail、Twist表达降低,过表达FOXG1组则相反。FOXG1在结直肠癌中高表达,这种基因的高表达能够促进结直肠癌细胞的侵袭和转移,对结直肠癌细胞的EMT起着重要的调控作用。     

The importance of regulatory ubiquitination in cancer and metastasis

Ubiquitination serves as a degradation mechanism of proteins, but is involved in additional cellular processes such as activation of NFκB inflammatory response and DNA damage repair. We highlight the E2 ubiquitin conjugating enzymes, E3 ubiquitin ligases and Deubiquitinases that support the metastasis of a plethora of cancers. E3 ubiquitin ligases also modulate pluripotent cancer stem cells attributed to chemotherapy resistance. We further describe mutations in E3 ubiquitin ligases that support tumor proliferation and adaptation to hypoxia. Thus, this review describes how tumors exploit members of the vast ubiquitin signaling pathways to support aberrant oncogenic signaling for survival and metastasis.     

Claudin-7 downregulation induces metastasis and invasion in colorectal cancer via the promotion of epithelial-mesenchymal transition

The dysregulation of the tight junctions (TJs) protein claudin-7 is closely related to the development and metastasis of colorectal cancer (CRC). The aim of this study was to investigate the expression of claudin-7 and characterize the relationship between claudin-7 expression and epithelial-mesenchymal transition (EMT) in CRC. In this study, the expression of claudin-7, E-cadherin, vimentin and snail-1 was detected by immunohistochemistry (IHC) in a set of 80 CRC specimens comprising 20 specimens each of well-differentiated, moderately differentiated, poorly differentiated and liver metastases tissues. The correlation between claudin-7 and EMT-related proteins in the stably transfected claudin-7 knockdown HCT116?cell line was analyzed by IHC, immunofluorescence (IF), Western blotting (WB) and nude mouse xenograft models. The results revealed that the expression of claudin-7 was downregulated as CRC tissue differentiation grade decreased, and that low claudin-7 expression corresponded to the downregulation of E-cadherin (r?=?0.725, p?<?0.001) and upregulation of vimentin (r?=??0.376, p?=?0.001) and snail-1 (r?=??0.599, p?<?0.001). Additionally, in the claudin-7 knockdown HCT116?cell line, the staining intensity and expression of E-cadherin was decreased, while the immunoreactivity and expression of vimentin and snail-1 was increased. Futhermore, the result of tumor formation experiment was consistent with CRC tissues. In conclusion, the expression of claudin-7 in CRC is downregulated as differentiation grade decreases. Claudin-7 downregulation may promote the invasion and metastasis of CRC by regulating EMT. Our results provide new perspectives for a potential therapeutic target for CRC.     

Apigenin up-regulates transgelin and inhibits invasion and migration of colorectal cancer through decreased phosphorylation of AKT

Colorectal cancer (CRC) is a major cause of morbidity and mortality throughout the world. Apigenin is a flavonoid that possesses various clinically relevant properties such as anti-tumour, anti-platelet and anti-inflammatory activities. Our results showed that apigenin has anti-proliferation, anti-invasion and anti-migration effects in three kinds of colorectal adenocarcinoma cell lines, namely SW480, DLD-1 and LS174T. Proteomic analysis with SW480 indicated that apigenin up-regulated the expression of transgelin (TAGLN) in mitochondria to exert its anti-tumour growth and anti-metastasis effects. Real-time quantitative polymerase chain reaction (RQ-PCR) and western blot confirm the up-regulation in all the three colorectal adenocarcinoma cells. An inverse correlation was observed between TAGLN expression and CRC metastasis in tissue microarray staining. TAGLN siRNA increased the viability of SW480. Apigenin decreased the expression of MMP-9 in a dose-dependent manner. Transfection of three truncated forms of TAGLN and wild type has identified TAGLN as a repressor of MMP-9 expression. A synergetic effect was observed in overexpression of TAGLN wild type and apigenin treatment which manifested as lowered phosphorylation of AKT Ser473 and ATK Thr308. In an orthotopic CRC model, apigenin inhibited tumour growth and metastasis to liver and lung. In conclusion, our research provided direct evidence that apigenin inhibited tumour growth and metastasis both in vitro and in vivo. Apigenin up-regulated TAGLN and hence down-regulated MMP-9 expression through decreasing phosphorylation of Akt at Ser473 and in particular Thr308 to prevent cell proliferation and migration.     

HERC3 regulates epithelial-mesenchymal transition by directly ubiquitination degradation EIF5A2 and inhibits metastasis of colorectal cancer

E3 ligase is widely reported to exert fundamental functions in cancers. Through rigorous bioinformatic analysis concentrating E3 ligases based on data from Genotype-Tissue Expression (GTEx) and data from The Cancer Genome Atlas (TCGA), HERC3 was indicated to be downregulated in colorectal cancer (CRC) and HERC3 downregulation showed poor overall survival (OS) and disease-free survival (DFS). Through qRT-PCR, western blotting and Immunohistochemistry (IHC), analytical results were validated based on tissues in Zhongshan hospital. Functionally, HERC3 was indicated to inhibit the migration, invasion and metastasis in vitro and in vivo through transwell assays, wound healing assays and vivo experiments. And HERC3 could regulate epithelial-mesenchymal transition (EMT) in CRC. Furthermore, immunoprecipitation (IP), coimmunoprecipitation (co-IP) and GST-pulldown assays indicated that HERC3 could directly interact with EIF5A2 in vitro and in vivo through the RCC1 domain in HERC3. And HERC3 could function as an E3 to promote the K27 and K48-linked ubiquitination degradation of EIF5A2 via the HECT domain in HERC3, besides, K47, K67, K85, and K121 in EIF5A2 were identified as ubiquitination sites. In addition, HERC3 was indicated to affect the migration, invasion and metastasis and further regulatE EMT via EIF5A2/TGF-/Smad2/3 signal. The present study may provide insight into the mechanism of EMT in CRC.Subject terms: Ubiquitins, Gastrointestinal cancer     

Rhodanine-based PRL-3 inhibitors blocked the migration and invasion of metastatic cancer cells

PRL-3, phosphatase of regenerating liver-3, plays a role in cancer progression through its involvement in invasion, migration, metastasis, and angiogenesis. We synthesized rhodanine derivatives, CG-707 and BR-1, which inhibited PRL-3 enzymatic activity with IC₅₀ values of 0.8 μM and 1.1 μM, respectively. CG-707 and BR-1 strongly inhibited the migration and invasion of PRL-3 overexpressing colon cancer cells without exhibiting cytotoxicity. The specificity of the inhibitors on PRL-3 phosphatase activity was confirmed by the phosphorylation recovery of known PRL-3 substrates such as ezrin and cytokeratin 8. The compounds selectively inhibited PRL-3 in comparison with other phosphatases, and CG-707 regulated epithelial-to-mesenchymal transition (EMT) marker proteins. The results of the present study reveal that rhodanine is a specific PRL-3 inhibitor and a good lead molecule for obtaining a selective PRL-3 inhibitor.     

Rock2 promotes the invasion and metastasis of hepatocellular carcinoma by modifying MMP2 ubiquitination and degradation

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is a downstream effector of Rho that plays an important role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). Matrix metalloproteinase 2 (MMP2) is a master regulator of tumor metastasis. In this study, we investigated the collections of Rock2 and MMP2 in HCCs and determined the potential role and molecular mechanism of Rock2 in MMP2-mediated invasiveness and metastasis. We found that Rock2 and MMP2 were markedly overexpressed in HCCs compared with the corresponding adjacent tissues, where a positive correlation in their expression was found. The knockdown of Rock2 significantly decreased MMP2 expression and inhibited the invasion and metastasis of HCC in vitro and in vivo. Additionally, the upregulation of MMP2 rescued the decreased migration and invasion induced by the knockdown of Rock2, whereas the knockdown of MMP2 decreased Rock2-enhanced HCC migration and invasion. Mechanistically, Rock2 stabilized MMP2 by preventing its ubiquitination and degradation. Together, our results link two drivers of invasion and metastasis in HCC and identify a novel pathway for MMP2 control.     

Effect of DPC4 gene on invasion and metastasis of colorectal carcinoma cells

To investigate the effect of DPC4 gene on invasion and metastasis of colorectal carcinomacells,the expression of DPC4 was detected in sixty-three samples of colorectal tumors and seven cases ofcolorectal mucosa.The biological behavior of tumors expressing DPC4 was evaluated (including tumorstaging,differentiation degree and metastasis).pcDNA3.1-DPC4 plasmid was constructed and transferredinto HCT116 cells not expressing DPC4.The cell models (DPC4~ -HCT116) steadily expressing DPC4 wereobtained.Compared with HCT116 and pcDNA3.1-HCT116 cells,the doubling time of DPC4~ -HCT116 cellswas lengthened obviously (P<0.01),the apoptosis rate of DPC4~ -HCT 116 cells was significantly increased(P<0.01),the cloning efficiency,cell adherency,migration and invasion ability of DPC4~ -HCT116 cells weredropped obviously (P<0.01).The number of cancer nodules was decreased significantly in abdominal cavityand liver of the nude mice inoculated with DPC4~ -HCT116 cells.The activity of MMP-9 and MMP-2 wasdetected by gelatin zymography.In comparison with HCT116 and pcDNA3.1-HCT116 cells,the activity ofMMP-9 was decreased in DPC4~ -HCT116 cells.Therefore,the down-regulation of DPC4 expression may beassociated with the carcinogenesis of colorectal carcinoma.DPC4 may inhibit the proliferation of coloncancer cell by restraining growth and inducing apoptosis,and the invasion and metastasis of colorectalcarcinoma cells.MMP-9 may be one of the downstream target genes regulated by DPC4.     

The role of laminin in cancer invasion and metastasis

Laminin, a basement membrane glycoprotein, has been implicated in a number of stages in tumour invasion and metastasis. In addition to its roles in cell adhesion and migration, laminin may be important in mediating interactions of tumour cells with the immune system and have more subtle roles in controlling metastatic behaviour. Recent work on the prognostic significance of laminin and the possible role of the molecule in antimetastasis therapy will also be discussed.     

卵巢癌侵袭转移机制的生物信息学研究进展

卵巢癌因其侵袭转移特性,致死率极高,居所有妇科恶性肿瘤之首。近年来随着高通量测序技术及生物信息学方法的快速发展,越来越多调控卵巢癌侵袭转移机制的相关生物大分子被发现。本文对卵巢癌侵袭转移机制的研究背景及现状进行了综述,归纳总结了侵袭转移机制相关调控因素,并对蛋白质组学和单细胞组学的生物信息学分析工具及数据库进行了汇总和介绍,以期为卵巢肿瘤细胞侵袭转移机制的深入研究提供理论依据和科研线索。     

具核梭杆菌促进结直肠癌发生发展机制研究进展

具核梭杆菌(Fusobacterium nucleatum)是一种人体共生菌,尤其富集于口腔,在特定情况下可导致机会感染.近年来,随着微生物群与健康或疾病相关性研究的深入,具核梭杆菌与结直肠癌(colorectal cancer,CRC)之间的关联性研究备受关注.大量临床研究表明,具核梭杆菌在CRC中更为富集,且进一步...     

circ_0000218通过靶向吸附miR-1182对宫颈癌HeLa细胞增殖、迁移和侵袭的影响

目的探讨环状RNA 0000218(circ_0000218)是否通过靶向吸附miR-1182从而影响宫颈癌HeLa细胞增殖、迁移和侵袭。方法采用实时荧光定量PCR(RT-qPCR)技术分析43例宫颈癌患者癌组织、癌旁组织中circ_0000218和miR-1182的表达水平。根据转染序列不同分为si-NC组、si-circ_0000218组、miR-NC组、miR-1182组、pcDNA组、pcDNAcirc_0000218组、si-circ_0000218+anti-miR-NC组、si-circ_0000218+anti-miR-1182组。运用细胞计数试剂盒(CCK-8)法、Transwell实验分析circ_0000218和miR-1182表达对HeLa细胞增殖、迁移和侵袭的影响。蛋白质印迹法检测Ki-67、基质金属蛋白酶2(MMP-2)和MMP9蛋白表达。双荧光素酶报告实验和RT-qPCR分析circ_0000218和miR-1182的靶向关系。癌旁组织与宫颈癌组织比较采用配对t检验,两组间比较采用独立样本t检验进行统计学分析。结果宫颈癌组织中circ_0000218表达量高于癌旁组织(4.17±0.32比1.00±0.05),而miR-1182表达量低于癌旁组织(0.33±0.03比1.00±0.05),差异具有统计学意义(P均<0.001)。与si-NC组比较,si-circ_0000218组HeLa细胞增殖活力(0.86±0.04比0.37±0.03)、迁移数量[(86.73±7.13)个比(38.52±3.19)个]和侵袭数量[(66.80±4.95)个比(26.58±2.55)个]以及Ki-67(0.57±0.05比0.18±0.02)、MMP-2(0.74±0.07比0.28±0.03)和MMP-9蛋白表达量(0.64±0.04比0.22±0.02)降低,差异有统计学意义(P均<0.001).与miR-NC组比较,miR-1182组HeLa细胞增殖活力(0.88±0.04比0.46±0.04)、迁移数量[(89.74±5.53)个比(46.63±3.79)个]和侵袭数量[(68.03±4.34)个比(34.63±3.37)个]以及Ki-67(0.59±0.04比0.24±0.02)、MMP-2(0.76±0.05比0.33±0.03)和MMP-9蛋白表达量(0.66±0.04比0.29±0.03)降低,差异有统计学意义(P均<0.001)。circ_0000218靶向负调控miR-1182表达。与si-circ_0000218+anti-miR-NC组比较,si-circ_0000218+anti-miR-1182组HeLa细胞增殖活力(0.35±0.03比0.76±0.04)、迁移数量[(35.58±3.11)个比(77.04±4.08)个]和侵袭数量[(25.44±2.29)个比(57.61±3.47)个]以及Ki-67(0.16±0.02比0.46±0.04)、MMP-2(0.26±0.02比0.65±0.04)和MMP-9蛋白表达量(0.20±0.02比0.57±0.04)升高,差异有统计学意义(P均<0.001)。结论circ_0000218通过靶向吸附miR-1182可促进宫颈癌HeLa细胞增殖、迁移和侵袭。     

Ecosystems of invasion and metastasis in mammary morphogenesis and cancer

The present review describes molecular and cellular mechanisms of cancer invasion and metastasis as compared to mammary gland development considering communication inside and between ecosystems. At the level of the individual cell, invasion programs are written by an ecosystem of signalling pathways each of which steers several invasion-related cellular activities. At the supracellular level, communication within the epithelial compartment involves cells of the same origin, but with different phenotypes including stem cells. A similar interaction occurs between the various cells of the stromal compartment. Crucial for our understanding of tumor or mammary gland ecosystems are the mutual interactions between cells of the epithelial and cells of the stromal compartment. An update is provided for endothelial cells, cancer-associated fibroblasts and macrophages that are implicated in angiogenesis, desmoplasia and inflammation respectively. At the level of the organism, distant ecosystems, comprising primary tumor site, sites of metastasis, bone marrow and endocrine glands among others, are in continuous contact through circulating cells and soluble ligands. Our review suggests consideration of these ecosystems when designing therapeutic strategies.     

CREB5在大肠癌转移中的调控机制

大肠癌转移过程中所涉及的细胞信号调控网络非常复杂, 寻找调控网络中的关键调控点对阐明大肠癌转移机制以及寻找药物治疗靶点均具有重要意义。研究表明, CREB5 (cAMP responsive element binding protein 5)可能为大肠癌转移相关信号调控网络中的关键基因。文章基于大肠癌表达谱数据, 根据CREB5基因表达值的大小对大肠癌的相关分子事件进行了富集分析, 发现这些分子事件与肿瘤转移密切相关。根据CREB5能够和c-Jun结合成为异二聚体的特点, 联合分析转录因子AP-1结合位点的富集情况, 筛选出在CREB5基因高表达组中表达上调、具有AP-1结合位点、且属于癌症通路的基因16个, 这些基因所构成的分子网络与细胞迁移功能类相关度最高。细胞迁移功能类主要由5个基因——CSF1R、MMP9、PDGFRB、FIGF和IL6所构成, 因此CREB5可能是通过调控这5个关键基因进而促进大肠癌的转移。     

Loss of E-cadherin promotes the growth,invasion and drug resistance of colorectal cancer cells and is associated with liver metastasis

The recent studies indicated that the epithelial cell adhesion molecule E-cadherin is a well-recognized molecule that is important in cell adhesion. To further investigate the molecular basis of this notion, we used small-interfering RNA to inhibit E-cadherin function and found that loss of E-cadherin promoted Colorectal cancer cell growth, invasion and drug resistance through induction of β-catenin nuclear translocation and epithelial-to-mesenchymal transition. Further analysis of E-cadherin expression with clinicopathologic parameters showed that E-cadherin expression decreased in Colorectal cancer patients who developed liver metastasis (P = 0.043). These findings indicate that E-cadherin loss in tumors contributes to progression and metastatic dissemination. Thus, E-cadherin can act as a central modulator of the cell biological phenotypes and a potential prognostic marker in Colorectal cancer.