Silencing of Lysyl Oxidase Gene Expression by RNA Interference Suppresses Metastasis of Breast Cancer

Objective: The aim of this study was to investigate possible mechanisms of LOX gene effects on invasion andmetastasis of breast cancer cells by RNA interference. Methods: LOX-RNAi-LV was designed, synthesized, andthen transfected into a breast cancer cell line (MDA-MB-231). Expression of LOX, MMP-2 and MMP-9 wasdetermined by real-time PCR, and protein expression of LOX by Western blotting. Cell migration and invasivenesswere assessed with Transwell chambers. A total of 111 cases of breast cancer tissues, cancer-adjacent normalbreast tissues, and 20 cases of benign lesion tissues were assessed by immunohistochemistry. Results: Expressionof LOX mRNA and protein was suppressed, and the expression of MMP-2 and MMP-9 was significantly lowerin the RNAi group than the control group (P<0.05), after LOX-RNAi-LV was transfection into MDA-MB-231cells. Migration and invasion abilities were obviously inhibited. The expression of LOX protein in breast cancer,cancer-adjacent normal breast tissues and benign breast tumor were 48.6% (54/111), 26.1% (29/111), 20.0% (4/20),respectively, associations being noted with clinical stage, lymph node metastasis, tumor size and ER, PR, HER2,but not age. LOX protein was positively correlated with MMP-2 and MMP-9. Conclusion: LOX displayed animportant role in invasion and metastasis of breast cancer by regulating MMP-2 and MMP-9 expression whichprobably exerted synergistic effects on the extracellular matrix (ECM).     

A molecular role for lysyl oxidase in breast cancer invasion

We identified previously an up-regulation in lysyl oxidase (LOX) expression,an extracellular matrix remodeling enzyme, in a highly invasive/metastatic human breast cancer cell line, MDA-MB-231, compared with MCF-7, a poorly invasive/nonmetastatic breast cancer cell line. In this study, we demonstrate that the mRNA expression of LOX and other LOX family members [lysyl oxidase-like (LOXL), LOXL2, LOXL3, and LOXL4] was observed only in breast cancer cells with a highly invasive/metastatic phenotype but not in poorly invasive/nonmetastatic breast cancer cells. LOX and LOXL2 showed the strongest association with invasive potential in both highly invasive/metastatic breast cancer cell lines tested (MDA-MB-231 and Hs578T). To determine whether LOX is directly involved in breast cancer invasion, LOX antisense oligonucleotides were transfected into MDA-MB-231 and Hs578T cells, and found to inhibit invasion through a collagen IV/laminin/gelatin matrix in vitro compared with LOX sense oligonucleotide-treated and untreated controls. In addition, treatment of MDA-MB-231 and Hs578T cells with beta-aminopropionitrile (an irreversible inhibitor of LOX enzymatic activity) decreased invasive activity. Conversely, MCF-7 cells transfected with the murine LOX gene demonstrated a 2-fold increase in invasiveness that was reversible by the addition of beta-aminopropionitrile in a dose-dependent manner. In addition, endogenous LOX mRNA expression was induced when MCF-7 cells were cultured in the presence of fibroblast conditioned medium or conditioned matrix, suggesting a role for stromal fibroblasts in LOX regulation in breast cancer cells. Moreover, the correlation of LOX up-regulation and invasive/metastatic potential was additionally demonstrated in rat prostatic tumor cell lines, and human cutaneous and uveal melanoma cell lines. These results provide substantial new evidence that LOX is involved in cancer cell invasion.     

沉默环状RNA hsa_circ_0001785表达对乳腺癌MDA-MB-231细胞增殖、迁移及侵袭能力的影响

目的:探究环状RNA（circRNA）hsa_circ_0001785在乳腺癌组织和细胞中的表达变化及其对乳腺癌细胞增殖、迁移和侵袭能力的影响。方法:qRT-PCR实验检测hsa_circ_0001785在乳腺癌组织和乳腺癌细胞（MDA-MB-231和SK-BP-3）中的相对表达水平；CCK-8和克隆形成实验检测沉默或上调表达hsa_circ_0001785对MDA-MB-231细胞活性和克隆形成能力的影响；划痕愈合实验和Transwell侵袭实验检测沉默或上调表达hsa_circ_0001785对MDA-MB-231细胞迁移及侵袭能力的影响。结果:hsa_circ_0001785在乳腺癌组织中的相对表达水平明显高于癌旁组织，hsa_circ_0001785在MDA-MB-231和SK-BP-3细胞中的相对表达水平明显高于人乳腺上皮细胞MCF10A。在MDA-MB-231细胞沉默hsa_circ_0001785，MDA-MB-231细胞的活性和克隆形成能力明显降低，迁移距离显著减少，侵袭能力也明显下降。而在MDA-MB-231细胞中上调表达hsa_circ_0001785，MDA-MB-231细胞的活性和克隆形成能力显著升高，迁移距离明显升高，侵袭能力也明显升高。结论:hsa_circ_0001785在乳腺癌组织和乳腺癌细胞（MDA-MB-231和SK-BP-3）中的表达水平明显升高；沉默hsa_circ_0001785显著抑制乳腺癌MDA-MB-231细胞的增殖、迁移和侵袭能力，而上调表达hsa_circ_0001785明显促进乳腺癌MDA-MB-231细胞的增殖、迁移和侵袭能力。     

Tumorigenicity of human breast cancer is associated with loss of the Ca2+-activated chloride channel CLCA2.

The human Ca2+-activated chloride channel-2 (CLCA2) is expressed in normal breast epithelium but not in breast tumors of different stages of progression. Northern analysis of nontransformed and transformed breast epithelial cell lines revealed CLCA2 expression in the nontransformed cell line MCF10A and the nontumorigenic cell line MDA-MB-453, whereas all tumorigenic cell lines were negative (MDA-MB-231, MDA-MB-435, MDA-MB-468, and MCF7). When stably reintroduced into CLCA2-negative MDA-MB-231 and MDA-MB-435 cells, CLCA2 expression reduced Matrigel invasion in vitro and inducibility of s.c. and metastatic tumors of MDA-MB-231 cells in nude mice. Our results suggest that CLCA2 may act as a tumor suppressor in breast cancer.     

环加氧酶-2 通过调控EMT促进乳腺癌MDA-MB-231 细胞的迁移和侵袭

[摘要] 目的：探讨环加氧酶-2（COX-2）在乳腺癌转移中的作用及其可能的机制。方法：收集从2015 年10 月至2018 年4 月在云南省肿瘤医院接受乳腺切除术的患者中获得的原发乳腺癌组织和脑转移乳腺癌组织临床病理样本共45 例,其中原发30 例、脑转移15 例。采用qPCR检测COX-2 在原位乳腺癌和脑转移乳腺癌组织中的表达。将COX-2 过表达重组病毒（LV6-COX2）或敲减COX-2 重组病毒（LV3-COX2 shRNA1、LV3-COX2 shRNA2）感染人乳腺癌MDA-MB-231 细胞并获得稳转细胞株后,CCK-8法检测COX-2 表达对MDA-MB-231 细胞增殖的影响,划痕实验和Transwell 法检测对MDA-MB-231 细胞迁移和侵袭的影响。qPCR和WB实验分析各组细胞中COX-2 mRNA和蛋白的表达水平,qPCR检测COX-2 表达对MDA-MB-231 细胞内EMT相关基因表达的影响。结果：COX-2 表达水平在脑转移乳腺癌患者组织中显著高于原位乳腺癌组织（P<0.01）;并且与乳腺癌患者肿瘤TMN分期有关。成功构建稳定过表达/敲减COX-2 的MDA-MB-231 细胞株。过表达COX-2 促进MDA-MB-231 细胞的迁移和侵袭（均P<0.01）,同时显著提高MMP2、MMP1、N-cadherin 和vimentin 的表达（均P<0.01）,但对细胞增殖无明显影响;而沉默COX-2 则有相反的作用,且可促进细胞增殖（P<0.05）。结论：COX-2 在脑转移乳腺癌组织中高表达,其可能通过调控EMT过程促进乳腺癌MDA-MB-231 细胞的迁移和侵袭。     

Gab2通过GSK-3β/Snail信号通路促进乳腺癌的上皮-间质转化

背景与目的：越来越多的证据显示,Grb2协同结合蛋白2(Grb2 binding protein-2,Gab2)与肿瘤的侵袭转移相关,但Gab2与乳腺癌上皮-间质转化(epithelial-mesenchymal transition,EMT)的关系尚不清楚。本研究旨在探讨Gab2对乳腺癌EMT标志物的影响,明确Gab2在乳腺癌侵袭和转移中的作用机制。方法：采用免疫组织化学染色法检测80例乳腺癌组织中Gab2及EMT标记物上皮性钙黏着蛋白(E-cadherin)、波形蛋白(vimentin)的表达情况并分析其相关性,用蛋白[质]印迹法(Western blot)检测乳腺组织Gab2的表达情况,采用小干扰RNA(siRNA)技术降低乳腺癌细胞系MDA-MB-231中Gab2的表达,采用划痕实验检测表皮生长因子(epithelial growth factor,EGF)刺激后转染细胞的侵袭能力变化,用Western blot检测敲低Gab2后MDA-MB-231细胞中E-cadherin及vimentin的表达情况,同时检测p-GSK-3β的表达情况、转录因子Snail转核情况。结果：Gab2在乳腺癌组织中的表达与E-cadherin的表达呈负相关,而与vimentin的表达呈正相关(P<0.05);乳腺癌组织中Gab2的表达量明显高于正常乳腺组织;siRNA质粒转染后,SiGab2/MDA-MB-231细胞组中Gab2蛋白的表达量明显降低,结果显示转染成功,划痕实验显示细胞的侵袭能力减弱,表明Gab2影响乳腺癌细胞系的侵袭能力;敲低Gab2后,MDA-MB-231细胞中的E-cadherin的表达明显升高,而vimentin的表达明显降低;GSK-3β的磷酸化受到抑制,而Snail在敲低Gab2的细胞核中的表达明显下调。结论：Gab2可以通过GSK-3β/Snail信号通路促进乳腺癌的EMT,从而促进乳腺癌的侵袭和转移。     

LINC02163靶向miR-338-3p影响乳腺癌细胞增殖、侵袭及迁移

背景与目的:长链非编码RNA(long non-coding RNA,lncRNA)已被发现在乳腺癌中失调,与肿瘤恶性行为密切相关。本研究旨在探究LINC02163靶向miR-338-3p对乳腺癌细胞增殖、侵袭及迁移的影响。方法:收集郑州人民医院2020年1月—2021年9月收治的9例乳腺癌患者的乳腺癌组织及距其2 cm外的癌旁组织样本,通过实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR)检测组织样本、人正常乳腺上皮细胞系(MCF-10A)和乳腺癌细胞系(MCF-7、BT-20、MDA-MB-231、T47D)中LINC02163的表达。将MDA-MB-231分为control组、sh-NC组、sh-LINC02163组、sh-LINC02163+inhibitor-NC组和sh-LINC02163+miR-338-3p inhibitor组。采用MTT法、transwell实验及划痕实验分别检测MDA-MB-231细胞活力、侵袭及迁移能力。采用蛋白质印迹法(West...     

环状RNA ciRS-7在三阴性乳腺癌中的表达及其对细胞侵袭和迁移的影响

 目的 探讨环状RNA ciRS-7在三阴性乳腺癌（TNBC）中的表达及其对细胞侵袭和迁移的影响。方法 通过qRT-PCR法检测乳腺癌组织和细胞中ciRS-7的表达水平,分析其与乳腺癌患者临床病理指标之间的关系。用划痕实验和Transwell实验检测沉默ciRS-7后MDA-MB-231和BT-549细胞的迁移和侵袭能力的变化。利用动物实验在体内进行验证。结果 TNBC组织中ciRS-7的相对表达量为（6.52±0.38）,显著高于Luminal型（1.56±0.17）（P<0.001）和HER2过表达型乳腺癌组织（2.27±0.66）（P<0.001）以及癌旁正常组织（0.83±0.09）（P<0.001）。ciRS-7表达与分子分型、肿瘤浸润和淋巴结转移明显相关（均P<0.05）;而与患者年龄、肿瘤直径和病理分级无关（均P>0.05）。沉默ciRS-7后,MDA-MB-231和BT-549细胞的迁移和侵袭明显减弱（均P<0.05）。ciRS-7敲低组肺转移瘤数明显减少（P<0.05）。结论 ciRS-7在TNBC中高表达,并可能增强TNBC细胞的侵袭和迁移。     

miR-199a-3p在乳腺癌中的表达及其作用

背景与目的：多种微小RNA(microRNA,miRNA)在乳腺癌中异常表达,在乳腺癌的发生、发展中起重要作用。miRNA可能是治疗乳腺癌的新靶点。该研究旨在探讨miR-199a-3p在乳腺癌中的表达水平,及其对乳腺癌癌细胞增殖和凋亡的影响。方法：运用实时定量聚合酶链式反应(quantitative real-time polymerase chain reaction,QRT-PCR)检测乳腺癌患者癌组织、癌旁正常组织、人乳腺癌细胞和人乳腺细胞中miRNA-199a-3p的表达水平,miR-199a-3p mimic(或inhibitor)转染乳腺癌细胞MDA-MB-231过表达(或沉默)miR-199a-3p的表达后,通过MTT法检测细胞增殖能力,Hoechst染色法和caspase-3活力测试检测细胞凋亡情况。结果：相对癌旁正常组织和人正常乳腺细胞,miR-199a-3p在乳腺癌患者癌组织和人乳腺癌细胞中表达下调。在MDA-MB-231中转染miR-199a-3p mimic过表达miR-199a-3p可抑制细胞增殖,促进其凋亡;在MDA-MB-231中转染miR-199a-3p inhibitor沉默miR-199a-3p可促进细胞增殖,抑制其凋亡。结论：miR-199a-3p在乳腺癌中表达下调,并通过调节乳腺癌细胞增殖和凋亡发挥抑癌作用。     

ALDH1A1增强乳腺癌细胞血管生成因子表达并促进共培养HUVEC细胞小管形成和侵袭能力

目的:探讨干细胞标志物醛脱氢酶1A1（ALDH1A1）对乳腺癌细胞血管生成因子表达的影响,以及对与乳腺癌细胞共培养的HUVEC细胞小管形成和侵袭能力的影响。方法:采用免疫组化检测了乳腺癌组织和乳腺增生组织中ALDH1A1的表达。使用ALDH1A1 shRNA或过表达ALDH1A1的pcDNA3.1质粒转染乳腺癌细胞（MCF-7和MDA-MB-231）,通过qRT-PCR和Western blot检测敲低或过表达ALDH1A1对乳腺癌细胞中血管内皮生长因子（VEGF）、缺氧诱导因子-1α（HIF-1α）和白细胞介素-12（IL-12）表达的影响。通过用1 μmol/L 的外源性RA和RAR阻断剂（AGN 193109）处理乳腺癌细胞48 h来考察视黄酸信号通路是否参与ALDH1A1对VEGF和HIF-1α的调控过程。将乳腺癌细胞（MCF-7和MDA-MB-231）和HUVEC细胞共培养来模拟肿瘤形成的微环境,并检测HUVEC的小管形成能力和细胞侵袭能力。结果:乳腺癌组织的ALDH1A1染色平均光密度显著高于乳腺增生组织,并且淋巴结转移的乳腺癌组织显著高于未淋巴结转移的乳腺癌组织（P＜0.05）。敲低ALDH1A1可显著降低MCF-7和MDA-MB-231细胞中VEGF和HIF-1α蛋白表达,并上调IL-12蛋白表达。然而,上调ALDH1A1表达则可逆转上述变化。外源性RA处理可显著上调MCF-7和MDA-MB-231细胞中VEGF和HIF-1α的表达,然而,RAR阻断剂处理可抑制MCF-7和MDA-MB-231细胞中VEGF和HIF-1α的上调。敲低乳腺癌细胞中ALDH1A1的表达可导致共培养的HUVEC细胞的小管形成能力和侵袭能力显著降低。而上调乳腺癌细胞中ALDH1A1的表达则可显著促进共培养的HUVEC细胞的小管形成能力和侵袭能力。结论:在乳腺癌细胞中,ALDH1A1通过激活HIF-1α和视黄酸信号通路来上调血管生成因子的表达并提高共培养的内皮细胞的血管生成能力,从而增加肿瘤的侵袭性。     

Lysyl oxidase regulates breast cancer cell migration and adhesion through a hydrogen peroxide-mediated mechanism

We have previously shown that lysyl oxidase (LOX) mRNA is up-regulated in invasive breast cancer cells and that catalytically active LOX facilitates in vitro cell invasion. Here we validate our in vitro studies by showing that LOX expression is up-regulated in distant metastatic breast cancer tissues compared with primary cancer tissues. To elucidate the mechanism by which LOX facilitates cell invasion, we show that catalytically active LOX regulates in vitro motility/migration and cell-matrix adhesion formation. Treatment of the invasive breast cancer cell lines, Hs578T and MDA-MB-231, with beta-aminopropionitrile (betaAPN), an irreversible inhibitor of LOX catalytic activity, leads to a significant decrease in cell motility/migration and adhesion formation. Conversely, poorly invasive MCF-7 cells expressing LOX (MCF-7/LOX32-His) showed an increase in migration and adhesion that was reversible with the addition of betaAPN. Moreover, a decrease in activated focal adhesion kinase (FAK) and Src kinase, key proteins involved in adhesion complex turnover, was observed when invasive breast cancer cells were treated with betaAPN. Additionally, FAK and Src activation was increased in MCF-7/LOX32-His cells, which was reversible on betaAPN treatment. Hydrogen peroxide was produced as a by-product of LOX activity and the removal of hydrogen peroxide by catalase treatment in invasive breast cancer cells led to a dose-dependent loss in Src activation. These results suggest that LOX facilitates migration and cell-matrix adhesion formation in invasive breast cancer cells through a hydrogen peroxide-mediated mechanism involving the FAK/Src signaling pathway. These data show the need to target LOX for treatment of aggressive breast cancer.     

FSIP1促进乳腺癌细胞迁移和侵袭并导致患者不良预后

目的 探讨乳腺癌组织中纤维鞘相互作用蛋白1(FSIP1)表达对乳腺癌细胞侵袭和迁移能力的影响及其与乳腺癌患者预后的关系,从而为乳腺癌的诊断和治疗提供一定的理论参考。方法 收集2004年1月—2018年12月于哈尔滨医科大学附属肿瘤医院确诊的404例乳腺癌患者的乳腺组织样本和病例资料,对收集的乳腺癌患者资料进行回顾性分析并采用Kaplan-Meier方法绘制生存曲线,采用免疫组织化学方法分析FSIP1在乳腺癌和癌旁组织中的表达情况,取乳腺癌细胞系MCF-7、MDA-MB-231、MDA-MB-435、SK-BR-3、T-47D及正常乳腺上皮细胞(HMECs)MCF-10A进行细胞培养,采用CRISPR/CAS9技术敲除乳腺癌细胞系MDA-MB-231和SK-BR-3中的FSIP1基因,通过Western blot实验检测各乳腺癌细胞系中FSIP1蛋白的表达情况并对FSIP1基因敲除结果进行检测,通过细胞迁移和侵袭实验评估FSIP1蛋白敲除对乳腺癌细胞迁移和侵袭能力的影响。结果 与正常乳腺上皮细胞(MCF-10A)相比,乳腺癌细胞系MCF-7、MDA-MB-231、MDA-MB-435、S...     

Analysis of <Emphasis Type="Italic">CUL-5</Emphasis> expression in breast epithelial cells,breast cancer cell lines,normal tissues and tumor tissues

Background  

The chromosomal location of CUL-5 (11q 22-23) is associated with LOH in breast cancer, suggesting that CUL-5 may be a tumor suppressor. The purpose of this research was to determine if there is differential expression of CUL-5 in breast epithelial cells versus breast cancer cell lines, and normal human tissues versus human tumors. The expression of CUL-5 in breast epithelial cells (HMEC, MCF-10A), and breast cancer cells (MCF-7, MDA-MB-231) was examined using RT-PCR, Northern blot analysis, and Western blot analysis. The expression of mRNA for other CUL family members (CUL-1, -2, -3, -4A, and -4B) in these cells was evaluated by RT-PCR. A normal human tissue expression array and a cancer profiling array were used to examine CUL-5 expression in normal human tissues and matched normal tissues versus tumor tissues, respectively.     

Beta-parvin inhibits integrin-linked kinase signaling and is downregulated in breast cancer

We analysed breast tumors and breast cancer cell lines for the expression of beta-parvin (ParvB), an adaptor protein that binds to the integrin-linked kinase (ILK). Quantitative RT-PCR indicated that ParvB mRNA was downregulated, by at least 60%, in four of nine breast tumors, relative to patient-matched normal mammary gland tissue. We also found that ParvB protein levels were reduced by > or =90% in five of seven advanced tumors, relative to matched normal breast tissue. Conversely, ILK protein and kinase activity levels were elevated in these tumors, suggesting that downregulation of ParvB stimulates ILK signaling. Western blot analyses indicated very low levels of ParvB protein in MDA-MB-231 and MCF7 breast cancer cells, facilitating functional studies of the effects of ParvB on ILK signaling. Expression of ParvB in MDA-MB-231 and MCF7 cells increased cell adhesion to collagen. ParvB inhibited ILK kinase activity, anchorage-independent cell growth and in vitro matrigel invasion by MDA-MB-231 cells. EGF-induced phosphorylation of two ILK targets, PKB (Ser473) and glycogen synthase kinase 3beta (Ser9), was also inhibited by ParvB. These results indicated that ParvB inhibits ILK signaling downstream of receptor tyrosine kinases. Our results suggest that loss of ParvB expression is a novel mechanism for upregulating ILK activity in tumors.     

miRNA-613在乳腺癌中的表达及作用机制

  目的  探讨乳腺癌中微小RNA (microRNA,miRNA)-613表达及作用机制。  方法  收集2017年5月至2018年5月91例于南充市中心医院手术切除的乳腺癌患者的组织标本,实时荧光定量PCR检测乳腺癌组织及癌旁组织标本、乳腺癌细胞系(MDAMB-231、MDA-MB-468、MCF-7)和正常乳腺上皮细胞系HBL-100中miRNA-613的表达水平,分析其与乳腺癌患者临床病理特征的关系。TCGA数据库分析miRNA-613与乳腺癌患者预后的关系。双荧光素酶报告实验检测miRNA-613与SOX9的3'UTR区的结合情况。将miRNA-613模拟物转染至MDA-MB-231细胞,CCK-8法和Transwell侵袭及迁移实验分别检测细胞增殖活性、侵袭和迁移能力的变化,Western blot检测细胞中SOX9、β-catenin、E-Cadherin和Vimentin蛋白的表达变化。  结果  miRNA-613在乳腺癌组织中表达明显低于癌旁组织(P < 0.05),并且miRNA-613表达与TNM分期和淋巴结转移密切相关(P < 0.05),TCGA生存数据显示miRNA-613表达与乳腺癌患者的总生存率无关(P>0.05)。乳腺癌细胞系中miRNA-613的表达明显低于正常乳腺上皮细胞系(P < 0.05),并且高侵袭转移性乳腺癌细胞系MDA-MB-231、MDA-MB-468中miRNA-613的表达明显低于低侵袭转移性乳腺癌细胞系MCF-7(P < 0.05)。双荧光素酶报告实验显示miRNA-613可与SOX9的3'UTR特异性结合。上调miRNA-613的表达能抑制MDA-MB-231细胞的增殖和侵袭迁移能力(P < 0.05),同时下调SOX9、β-catenin和Vimentin蛋白的表达(P < 0.05),并上调ECadherin蛋白的表达(P < 0.05)。  结论  在乳腺癌组织和细胞中miRNA-613异常低表达,miRNA-613可能通过调控SOX9、Wnt/β-catenin信号通路抑制乳腺癌细胞的增殖、侵袭转移及上皮间质转化。      

miR-101、EZH2和MYC调控乳腺癌MDA-MB-231细胞增殖能力的机制

目的:研究miR-101、EZH2和MYC对乳腺癌MDA-MB-231细胞增殖的影响,并探究三者之间的调控机制。方法:以实时荧光定量PCR法检测三阴型乳腺癌组织及相应正常乳腺组织中miR-101、EZH2与MYC的表达,以及乳腺癌细胞系和正常乳腺细胞中miR-101的表达水平。以LipofectamineTM 2000将miR-101 mimics、EZH2 siRNA和MYC siRNA以及相应的阴性对照转染至MDA-MB-231细胞,Western blot法检测EZH2、MYC蛋白的表达,MTT法检测MDA-MB-231细胞的增殖能力。结果:相对于正常乳腺组织,三阴型乳腺癌组织中miR-101 mRNA的表达降低,而EZH2、MYC mRNA表达则显著升高;三阴型乳腺癌细胞中miR-101 mRNA的表达低于正常乳腺细胞MCF-10A。miR-101 mimics转染使MDA-MB-231细胞中miR-101 mRNA含量显著升高。miR-101过表达抑制EZH2、MYC的表达;EZH2敲减也抑制了MYC蛋白的表达。EZH2或MYC敲减可使miR-101 mRNA的表达显著升高。MTT实验结果示,miR-101过表达或敲减EZH2、MYC均可抑制MDA-MB-231细胞的增殖能力。结论:miR-101通过EZH2与MYC形成反馈环路调控MDA-MB-231细胞的增殖能力。     

Differential expression of the α2,3-sialic acid residues in breast cancer is associated with metastatic potential

Aberrant sialylation is closely associated with the malignant phenotype of cancer cells and metastatic potential. However, the precise nature of the molecules in breast cancers has not been unveiled. In this study, we investigated the expression levels of α2,3-sialic acid residues of 50 primary tumor cases, 50 pair-matched lymph node metastasis tumor samples and in the MDA-MB-231, T-47D and MCF-7 breast cancer cell lines with different metastatic potential. The expression of α2,3-sialic acid residues was analyzed by histochemistry, cytochemistry and flow cytometry with Maackia amurensis lectin (MAL). The invasion and migration abilities of cells were examined using cell adhesion and transwell in vitro assays. Pair-matched lymph node metastasis tumor samples exhibited higher levels of expression of α2,3-sialic acid residues compared to that of primary tumors (P=0.0432). Furthermore, of 38 tumors cases in T1/T2 stages, 31 (81.58%) had weak staining for MAL, which specifically binds to α2,3-sialic acid residues, whereas of 12 tumor cases in T3/T4 stages, only 1 (8.33%) had weak reactions for MAL. The highly metastatic breast cancer cell line MDA-MB-231 exhibited the strongest binding to MAL and the highest expression levels of α2,3-sialic acid residues among the selected cell lines, depending on mRNA expression levels of α2,3-sialyltransferase gene. The adhesion, invasion and migration activities confirmed that MDA-MB-231 exhibited the greater cell adhesion to, migration toward and invasion to Matrigel. Taken together, the high expression of α2,3-sialic acid residues in breast cancer was associated with metastatic potential. This property may be important for developing new therapeutic approaches for breast cancer.