Cullin3 promotes breast cancer cells metastasis and epithelial-mesenchymal transition by targeting BRMS1 for degradation

Metastasis is the leading cause of death in breast cancer (BC) patients. However, until now, the mechanisms of BC metastasis remain elusive. Cullin3 is a highly conserved Cullin family member present in the genomes of all eukaryotes, which has been proposed as an oncogene in many types of tumors; however, its role and underlying mechanisms in BC remain unclear. Here we show that Cullin3 is elevated in BC and its expression level is positively correlated with metastasis. Overexpression of Cullin3 in BC cells increased proliferation, epithelial-mesenchymal transition, migration and invasion in vitro, and enhanced tumorigenic and metastatic capacities in vivo. In contrast, silencing Cullin3 in aggressive and invasive BC cells inhibited these processes. Mechanistically, we found Cullin3 exerts its function through promoting BRMS1 protein degradation, which was associated with EMT, migration and invasion. BRMS1 overexpression blocked Cullin3-driven EMT, and metastasis. Our results, for the first time, portray a pivotal role of Cullin3 in stimulating metastatic behaviors of BC cells. Targeting Cullin3 may thus be a useful strategy to impede BC cell invasion and metastasis.     

BMP4 通过诱导EMT 促进肝癌迁移侵袭*

目的:检测BMP 4 在肝癌中的表达并探讨BMP 4 在诱导肝癌EMT 中的作用,进而研究其对肝癌细胞迁移侵袭能力的影响。方法:采用免疫组织化学方法检测肝癌组织中BMP 4 的表达,分析其与肝癌临床病理资料之间的关系。将BMP 4 表达质粒转染至肝癌细胞系HepG2 中,诱导BMP 4 外源性过表达。观察BMP 4 转染前、后HepG2 的细胞形态学改变;Westernblot检测转染前、后HepG2 中BMP 4、EMT 相关蛋白（E-cadherin、Vimentin）表达变化情况;划痕和侵袭实验检测BMP 4 对细胞迁移侵袭能力的影响。结果:BMP 4 与患者的年龄、病理分级、临床分期、不良预后密切相关。BMP 4 过表达后HepG2 呈现典型的EMT 形态学改变,E-cadherin 表达下调、Vimentin 表达上调、细胞的迁移侵袭能力显著增强。结论:BMP 4 与肝癌临床病理资料密切相关,并可能通过诱导EMT 促进肝癌细胞的迁移侵袭能力。      

IR-A/IGF-1R-mediated signals promote epithelial-mesenchymal transition of endometrial carcinoma cells by activating PI3K/AKT and ERK pathways

Background: Obesity is a risk factor for endometrial cancer (EC). However, it is not known how insulin receptor isoform A (IR-A) and insulin-like growth factor 1 receptor (IGF-1R), cognate receptors for insulin and IGFs, respectively, regulate malignant behaviors of EC. In this study, we examined the biological effects of IR-A/IGF-1R, explored the downstream signaling cascades, and assessed the therapeutic potential of targeting IR-A/IGF-1R in vivo.

Methods: The expression levels of IR-A and IGF-1R were examined by qRT-PCR and Western blotting. Upon down-regulating IR-A and/or IGF-1R by sh-IR-A and/or sh-IGF-1R, respectively, cell migration, invasion, apoptosis, and epithelial-mesenchymal transition (EMT) were examined by wound healing, transwell invasion, flow cytometry, and Western blotting, respectively. Furthermore, the effect of sh-IR-A and/or sh-IGF-1R on phosphatidylinositide 3-kinases (PI3K)/AKT and ERK pathways was measured by Western blotting. Lastly, we monitored xenograft growth and EMT in vivo.

Results: Both IR-A and IGF-1R were significantly up-regulated in EC cells. Knockdown of IR-A or IGF-1R alone was sufficient to reduce migration and invasion, enhance apoptosis, and inhibit EMT of EC cells, and the most significant alterations were observed in cells co-transfected with sh-IR-A+ sh-IGF-1R. These phenotypes were associated with inactivating PI3K/AKT and ERK signaling by sh-IR-A and/or sh-IGF-1R. Consistent with in vitro findings, sh-IR-A or sh-IGF-1R significantly inhibited xenograft growth and EMT in vivo.

Conclusion: IR-A and IGF-1R-mediated signals, by activating PI3K/AKT and ERK pathways, can induce multiple malignant phenotypes of EC cells. Therefore, targeting IR-A or IGF-1R may provide therapeutic benefits for EC.     

宫颈癌上皮-间质转化的研究进展

宫颈癌是常见的妇科恶性肿瘤之一,严重威胁着妇女的健康,且发病率近几年来趋于年轻化。尽管使用了先进的筛查方法和预防性疫苗,但在治疗方案极为有限和副作用严重的情况下,超过一半的宫颈癌病例被诊断为晚期。如何解决上述问题,需从分子生物学层面来更好的认识宫颈癌。其中上皮-间质转化（epithelial-mesenchymal transition,EMT）是近年来研究的热点,EMT是由上皮细胞表型向间质细胞表型转变的可逆的生物学过程,EMT可促进宫颈癌细胞的迁移、侵袭,进而促进肿瘤的转移,影响患者的预后。本文综合目前的研究进展,将对近年来宫颈癌的EMT相关研究进展作一综述。     

PP4R1 interacts with HMGA2 to promote non-small-cell lung cancer migration and metastasis via activating MAPK/ERK-induced epithelial-mesenchymal transition

Protein phosphatase 4 regulatory subunit 1 (PP4R1) has been shown to play a role in the regulation of centrosome maturation, apoptosis, DNA repair, and tumor necrosis factor signaling. However, the function of PP4R1 in non-small-cell lung cancer remains unclear. In this study, we identify PP4R1 as an oncogene through Oncomine database mining and immunohistochemical staining, and we showed that PP4R1 is upregulated in lung cancer tissues as compared with that in normal lung tissues and correlated with a poor prognosis in lung cancer patients. Furthermore, in vitro study by wound-healing and Transwell assay showed that PP4R1 could promote migration and invasion of lung cancer cells. Mechanistic investigations revealed that PP4R1 could cooperate with high mobility group AT-hook 2 and thereby promotes epithelial-mesenchymal transition via MAPK/extracellular receptor kinase activation. Taken together, our study provides a rich resource for understanding PP4R1 in lung cancer and indicates that PP4R1 may serve as a potential biomarker in lung cancer therapies.     

Long non-coding RNA AOC4P suppresses hepatocellular carcinoma metastasis by enhancing vimentin degradation and inhibiting epithelial-mesenchymal transition

Increasing evidence indicates that long non-coding RNAs (lncRNAs) regulate diverse cellular processes, including cell growth, differentiation, apoptosis, and cancer progression. However, the function of lncRNAs in the progression of hepatocellular carcinoma (HCC) remains largely unknown. We performed a comprehensive microarray analysis of lncRNA expression in human HCC samples. After validation in 108 HCC specimens, we identified a differentially expressed novel tumor suppressive lncRNA termed amine oxidase, copper containing 4, pseudogene (AOC4P). The level of AOC4P expression was significantly downregulated in 68% of HCC samples and negatively correlated with advanced clinical stage, capsule invasion and vessel invasion. Low AOC4P expression correlated with poor prognostic outcomes, serving as an independent prognostic factor for HCC. In vitro functional assays indicated that AOC4P overexpression significantly reduced cell proliferation, migration and invasion by inhibiting the epithelial-mesenchymal transition (EMT). RNA immunoprecipitation assays demonstrated that AOC4P binds to vimentin and promotes its degradation. Animal model experiments confirmed the ability of AOC4P to suppress tumor growth and metastasis. Taken together, our findings suggest that AOC4P lncRNA acts as an HCC tumor suppressor by enhancing vimentin degradation and suppressing the EMT. By clarifying the mechanisms underlying HCC progression, these findings promote the development of novel therapeutic strategies for HCC.     

MicroRNA-29a靶向抑制PTEN基因诱导非小细胞肺癌细胞上皮间质转化的机制研究

目的:探讨microRNA-29a（miR-29a）及其靶蛋白PTEN在TGF-β1诱导非小细胞肺癌（non-small cell lung cancer,NSCLC）细胞上皮间质转化（epithelial-mesenchymal transition,EMT）中的作用机制。方法:选择A549细胞经终浓度为10 ng/ml TGF-β1诱导48 h后,分为Blank组（不转染任何序列）、阴性对照（negative control,NC）组（转染阴性对照序列）、IN组（转染miR-29a inhibitors）、siRNA组（转染PTEN-siRNA）和IN+siRNA组（共转染miR-29a inhibitors和PTEN-siRNA）。普通显微镜观察各组细胞形态学变化;免疫荧光检测各组细胞中E-cadherin表达水平;qRT-PCR法检测EMT相关因子及PTEN mRNA表达水平;Western blotting法检测转染后EMT相关因子、PTEN、Akt和p-Akt蛋白的表达;划痕实验检测各组细胞迁移能力。构建裸鼠移植瘤模型,观察肿瘤生长,免疫组化检测裸鼠肿瘤组织中PTEN及EMT相关因子蛋白表达水平。结果:A549细胞转染miR-29a inhibitors后TGF-β1诱导细胞的上皮间质转化显著受到抑制,N-cadherin、Vimentin及Slug的mRNA和蛋白表达水平在IN组中显著低于Blank组和NC组,但在siRNA组和IN+siRNA组中显著上调（均P<0.05）。与Blank组和NC组相比,IN组PTEN mRNA和蛋白表达水平明显升高,且p-Akt的表达显著降低,细胞迁移率显著下降,而siRNA组和IN+siRNA组PTEN mRNA和蛋白表达明显降低,p-Akt的表达显著上升,细胞迁移率显著升高（均P<0.05）。裸鼠移植瘤实验结果显示与Blank组和NC组相比,IN组肿瘤生长较慢,重量降低,E-cadherin和PTEN蛋白表达显著升高,N-cadherin、β-catenin、Vimentin、Slug蛋白表达显著降低（均P<0.05）。结论:TGF-β1能诱导NSCLC细胞发生EMT,且能上调miR-29a并抑制PTEN的表达水平;抑制miR-29a的表达水平可能通过上调靶基因PTEN,促进Akt磷酸化,抑制EMT的发生。     

Fas通路通过激活ERK1/2通路在结肠癌细胞中诱导上皮-间质转化

  目的   探索Fas通路在结肠癌细胞中诱导上皮间质转化(epithelial-mesenchymal transition, EMT)的分子机制。   方法   分别对结肠癌细胞SW480及DLD1予以低剂量FasL(12.5 ng/mL)处理。作用3d后分别提取实验组和对照组细胞的总蛋白、总RNA, 并进行Western blot、RT-PCR检测, 分析FasL作用下结肠癌细胞的上皮标记物、间质标记物以及EMT相关的转录因子的表达状况。在低剂量FasL作用3d后行免疫荧光检测, 观察EMT相关转录因子在细胞内的分布情况。建立稳定敲除Snail及Twist的结肠癌细胞系, 再予以低剂量FasL刺激, 采用Western blot、RT-PCR检测是否发生EMT过程。对结肠癌细胞SW480予以低剂量FasL(12.5 ng/mL)处理后, 通过Western blot检测实验组和对照组细胞ERK1/2通路及p38通路的激活状况。对SW480细胞进行信号通路抑制剂的预处理, 再予以低剂量FasL刺激, 采用Western blot、RT-PCR检测是否发生EMT过程, 从而探索Fas通路诱导EMT的可能机制。   结果   低剂量FasL可使结肠癌SW480和DLD1细胞的上皮标记物表达下调, 间质标记物表达上调, EMT相关转录因子在细胞核周聚集, 细胞发生梭形改变, 提示发生EMT。而将结肠癌细胞的Snail或Twist基因敲除后, FasL的上述诱导作用明显减弱。低剂量FasL可激活结肠癌细胞的ERK1/2通路激活, 而ERK抑制剂可减弱FasL诱导的EMT过程   结论   Fas通路可能通过激活ERK1/2通路诱导结肠癌细胞发生EMT。      

上皮间质转化与肿瘤侵袭转移关系的研究进展

上皮间质转化（epithelial-mesenchymal transition,EMT）是指上皮细胞失去极性,失去与基底膜的连接等上皮表型,通过特定程序转化为具有间质表型的生物学过程,从而获得了较高的迁移与侵袭、抗凋亡和降解细胞外基质的能力,与肿瘤的侵袭转移密切相关。参与这一过程的细胞内信号转导途径主要有：TGF-β信号途径、PI3K/AKT途径、Notch信号通路、Wnt信号通路等。本文就EMT在肿瘤侵袭转移中的作用及其分子机制的研究作一综述。     

PAK5通过上皮-间质转化促进人乳腺癌细胞侵袭

目的:探讨p21活化激酶-5（p21-activated kinase 5,PAK5）蛋白对乳腺肿瘤细胞侵袭转移的作用机制。方法:观察PAK5过表达对乳腺癌细胞形态的影响,人乳腺肿瘤细胞MCF-7通过慢病毒感染稳定表达Flag-PAK5。然后提取感染细胞的总蛋白进行蛋白免疫印迹检测上皮-间质转化（EMT）标志物上皮-钙黏蛋白（E-cadherin）,纤维连接蛋白（Fibronectin）和波形蛋白（vimentin）的表达。最后通过Transwell实验检测过表达PAK5对乳腺癌细胞迁移和侵袭的影响。结果:过表达PAK5蛋白能够使细胞形态由鹅卵石样像梭形变化,下调E-cadherin蛋白,促进乳腺癌细胞迁移和侵袭。结论:PAK5可能参与调节乳腺肿瘤细胞发生上皮－间质转化,促进乳腺肿瘤侵袭转移的发生。