转染肿瘤坏死因子-α及MDR1反义RNA逆转乳腺癌多药耐药的研究

目的:转染肿瘤坏死因子-α(TNF-α)cDNA和多药耐药基因(MDR1)的反义RNA到乳腺癌耐药细胞株MCF-7/ADR中进行表达,并观察它们在乳腺癌耐药逆转中的作用.方法:应用RT-PCR和DNA重组技术构建反义绿色荧光蛋白pEGFP-MDR1融合蛋白表达载体和红色荧光蛋白pDsRed2-TNF-α融合蛋白表达载体,分别和同时导入乳腺癌耐药细胞株MCF-7/ADR中进行表达,检测转染前后细胞的生长曲线、细胞凋亡程度、MDR1-mRNA和P糖蛋白(P-gp)表达情况及对ADR敏感性的变化.结果:转染后的细胞生长明显减慢,凋亡率显著增加,MDR1-mRNA和P糖蛋白(P-gp)表达明显降低,对ADR的耐药性明显下降,敏感性增加.结论:联合运用不同的逆转耐药机制,将TNF-αcDNA及MDR1反义RNA分别或同时导入乳腺癌耐药细胞中,能有效达到逆转耐药的目的.     

血清外泌体miR-575与ER阳性乳腺癌患者他莫昔芬辅助治疗预后的相关性研究

目的研究血清外泌体miR-575水平与雌激素受体(ER)阳性乳腺癌患者他莫昔芬辅助内分泌治疗预后的相关性。方法通过生物信息学分析miR-575表达水平与乳腺癌患者总体生存率的关系。采集接受他莫昔芬辅助内分泌治疗的162例ER阳性乳腺癌患者的血液样本作为观察组,另外收集165例非癌志愿者的血液样本作为对照组,以实时荧光定量PCR法检测血清外泌体miR-575表达水平。观察组患者至少随访5年,根据患者对他莫昔芬的耐药情况将其分为抵抗组和敏感组,分析血清外泌体miR-575表达水平与术后疾病进展的关系。采用单因素和多因素Cox回归分析影响ER阳性乳腺癌患者他莫昔芬治疗预后的临床因素,并绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC)。结果生物信息学结果显示,miR-575在乳腺癌组织中的表达水平明显高于正常乳腺组织(P<0.001);且在ER阳性患者中,miR-575表达水平升高与Nottingham病理学分级较高以及预后不良有关(P<0.05)。观察组患者血清外泌体miR-575相对表达水平高于对照组1.834(1.168,2.519)vs.1.003(0.901,1.217),Z=-8.871,P<0.001;观察组患者血清外泌体与乳腺癌组织miR-575相对表达水平呈正相关(rs=0.726,P<0.001)。随访5年,110例患者对他莫昔芬耐药(抵抗组),52例对他莫昔芬敏感(敏感组)。抵抗组血清外泌体miR-575相对表达水平明显高于敏感组2.097(1.700,3.163)vs.1.168(0.947,1.524),Z=-7.164,P<0.001。Kaplan-Meier曲线显示,血清外泌体miR-575高表达组患者中位疾病进展时间短于低表达组(P<0.001)。Cox回归分析和ROC曲线结果显示,血清外泌体miR-575高表达是ER阳性乳腺癌患者接受他莫昔芬辅助内分泌治疗预后不良的独立危险因素(P<0.05),预测5年疾病进展的AUC为0.850(95%CI0.789~0.910)。结论血清外泌体miR-575表达水平较高预示着ER阳性乳腺癌患者接受他莫昔芬辅助内分泌治疗预后不良,有望成为预测他莫昔芬敏感性的一个重要参考指标。     

探究外泌体hsa-miR-377在糖尿病肾病中的表达及其相关临床意义

目的本研究旨在探究糖尿病肾病患者和健康体检者血液样本中外泌体hsa-miR-377的表达量,以表明其参与糖尿病肾病的致病过程中。方法本研究通过收集临床糖尿病肾病患者和健康体检者的血液样本进行外泌体分离鉴定,通过透射电子显微镜对血液样本获得的离心小球进行分析,再进行RT-PCR分析外泌体中小RNA分子的表达。结果 TEM发现糖尿病肾病的血液样本中存在外泌体,且外泌体形态在镜下很明显,RT-PCR对外泌体中小RNA分子的表达结果显示外泌体中hsa-miR-377的表达量(0.65±0.05)普遍高于正常体检者血液样品(0.29±0.05)(P0.01)。结论外泌体hsa-miR-377可能参与糖尿病肾病的致病过程,且可能是糖尿病肾病的一个潜在诊断标志物。     

沉默PARP-1对乳腺癌细胞MCF-7顺铂耐药的影响

目的:探究沉默多聚腺苷二磷酸核糖聚合酶1(PARP-1)对乳腺癌细胞MCF-7顺铂耐药的影响及可能的作用机制。方法:Western blot及real-time PCR实验检测乳腺癌细胞株MCF-7及相应耐药细胞株MCF-7/DDP中PARP-1的表达情况。采用转染PARP-1小干扰RNA(siRNA)的方法沉默乳腺癌耐药细胞株MCF-7/DDP中PARP-1的表达,CCK-8法检测细胞活力,流式细胞术检测细胞凋亡,Western blot检测PARP-1、Bcl-2、Bax、cleaved caspase-3、caspase-3、细胞色素C(Cyto-C)、细胞外调节蛋白激酶(ERK)和磷酸化ERK(p-ERK)的蛋白水平。结果:耐药细胞株MCF-7/DDP中PARP-1的mRNA及蛋白表达水平均明显高于亲本细胞株(P0.05);并且在亲本细胞株MCF-7中加入顺铂刺激后,PARP-1的蛋白表达水平明显升高(P0.05)。沉默PARP-1可诱导乳腺癌耐药细胞株MCF-7/DDP的凋亡,增强细胞对顺铂的敏感性,还可下调Bcl-2/Bax和p-ERK的蛋白水平,同时上调cleaved caspase-3及Cyto-C的蛋白水平。而应用ERK特异性抑制剂U0126后,PARP-1沉默组的细胞活力进一步降低。结论:沉默乳腺癌耐药细胞株MCF-7/DDP中PARP-1的表达可恢复细胞对顺铂的敏感性,促进细胞经线粒体途径的凋亡,其机制可能与其抑制ERK的磷酸化,进而阻断该信号通路有关。     

PD-1、CTLA-4和MMP9在伴或不伴淋巴结转移乳腺癌患者外泌体中的表达

为探讨外泌体PD-1、CTLA-4和基质金属蛋白酶9(matrix metalloproteinase 9,MMP9)在乳腺癌及淋巴结转移患者中的表达,选取2016年6月至2018年6月就诊的乳腺癌女性患者,分为对照组(无淋巴结转移)和转移组(有无淋巴结转移),另选取健康女性为健康组。采用免疫组化检测乳腺癌组织中PD-1、CTLA-4和MMP9的表达;分离外周血中的外泌体,采用流式细胞术检测外泌体PD-1、CTLA-4和MMP9的表达。免疫组化的结果显示:对照组乳腺癌组织中PD-1和CTLA-4的光密度(D)分别为63.5±6.9和56.4±6.2,转移组分别为79.2±12.8和71.1±12.1,两组差异无统计学意义(P 0.05);对照组乳腺癌组织中MMP9的D为98.4±10.7,转移组为153.1±16.8,两组差异具有统计学意义(P=0.013)。流式细胞术结果显示:对照组和转移组PD-1~+外泌体比例分别为(0.782±0.090)%和(0.816±0.011)%,显著高于健康组[(0.269±0.049)%,P0.001];对照组和转移组CTLA-4~+外泌体比例分别为(3.995±0.233)%和(4.122±0.197)%,显著高于健康组[(2.310±0.200)%,P0.001];PD-1~+和CTLA-4~+外泌体在对照组和转移组之间差异无统计学意义(P 0.05);对照组和转移组MMP9~+外泌体比例分别为(0.874±0.083)%和(1.290±0.108)%,与健康组[(0.515±0.083)%]比较,差异具有统计学意义(P0.05);转移组MMP9~+外泌体比例显著高于对照组(P=0.006)。由此可见,外泌体PD-1和CTLA-4可用于乳腺癌的早期诊断,外泌体MMP9可作为一个有效的靶点应用于乳腺癌转移的早期预警和术后监测。     

脐带间充质干细胞外泌体抑制BEL7402细胞增殖与迁移

目的 研究脐带间充质干细胞(hUC-MSCs)外泌体对人肝癌细胞株BEL7402细胞增殖与迁移能力的影响.方法 收集hUC-MSCs培养上清,采用超速离心法收集hUC-MSCs外泌体,利用透射电镜检测外泌体形态大小,使用纳米粒度颗粒跟踪分析仪(Nanosight,NTA)检测外泌体粒径大小,使用Western blot技术检测外泌体表面标记物表达情况;利用CCK-8实验观察hUC-MSCs外泌体作用BEL7402细胞后,细胞的增殖情况;运用Transwell迁移实验观察hUC-MSCs外泌体对BEL7402细胞迁移能力的影响.结果 从hUC-MSCs培养上清中成功分离hUC-MSCs外泌体,经检测hUC-MSCs外泌体呈茶托状结构,粒径大小位于50～150nm之间,表面标志物Alix、CD63、CD81及HSP70表达阳性.细胞功能学实验发现:与对照组相比,hUC-MSC-外泌体处理后的BEL7402细胞的增殖和迁移能力均下降.结论 hUC-MSC-外泌体抑制BEL7402细胞的增殖、迁移.     

人脐带间充质干细胞来源外泌体的提取、鉴定和蛋白组学分析

背景:现有的外泌体蛋白组学研究中,只有不同来源外泌体或者不同条件下分泌的外泌体之间的蛋白组学对比,没有外泌体和其母体细胞之间的对比分析。目的:对人脐带间充质干细胞来源外泌体进行提取鉴定和蛋白组学分析。方法:培养人脐带间充质干细胞并采用超滤序贯超离法提取外泌体,通过透射电镜、纳米颗粒跟踪分析、蛋白质定量、蛋白质印迹法及蛋白组学分析等技术鉴定。结果与结论:(1)提取的外泌体分散度较好且均一,多为杯状圆形或类圆形的膜性小囊泡,可见囊泡的双膜性结构,中央为低电子密度成分,分布较集中且边界清晰;(2)外泌体粒径分布峰值为(129.5±8.7) nm,膜表面带负电荷,浓度为8.375×1010粒子/mL,平均zeta电位为(-28.1±3.6) mV;(3)外泌体有特征性膜蛋白CD9、CD63的表达;(4)蛋白组学分析外泌体中高表达的蛋白质大多参与RNA剪接、mRNA加工、蛋白折叠等生物过程,参与RNA/DNA等遗传物质及蛋白质的合成、加工、降解过程,参与组成多种细胞器及亚细胞膜结构,参与多条信号通路、细胞黏附、细胞外基质受体相互作用,与多种疾病和病毒致癌也密切相关;(5)通过分析认为外泌体与其母...     

乳腺癌患者血清外泌体 lncRNA HOTTIP 的表达及临床意义

目的 探究血清外泌体 lncRNA HOTTIP 在乳腺癌 (breast cancer, BC) 患者中的临床预后价值。 方法 采用试剂盒提取 98 例 BC 患者、 50 例良性乳腺疾病 (benign breast disease, BBD) 患者和 50 例健康 人血清中的外泌体; 采用 RT-qPCR 检测血清外泌体中 HOTTIP 的表达水平, 进一步分析 HOTTIP 表达与患 者临床病理学特征及总生存期的关系。 结果 BC 患者血清外泌体中 lncRNA HOTTIP 的表达水平明显高于 BBD 患者 (t = 8. 790, P< 0. 001) 和正常健康人 (t = 11. 540, P< 0. 001), 且手术后 BC 患者血清外泌体中 的 HOTTIP 水平显著降低 ( t = 14. 570, P< 0. 001)。 临床病理分析显示, 高血清外泌体 HOTTIP 水平与 HER2 表达水平、 淋巴结转移和 TNM 分期显著相关 (P均 ߹0. 05)。 生存分析表明, 血清外泌体 HOTTIP 高表 达组 BC 患者的 5 年生存率显著低于低表达组 ( χ 2 = 5. 548, P = 0. 019); 多因素分析显示, 血清外泌体 HOTTIP 高表达是导致 BC 患者预后不佳的独立危险因素 ( HR = 2. 454, 95 % CI: 1. 142 ~ 7. 005, P = 0. 031)。 结论 血清外泌体 lncRNA HOTTIP 在 BC 中表达上调, 其高表达提示肿瘤的恶性进展和患者的不 良预后, 有望成为 BC 患者预后评估的非侵入性生物标志物。     

幽门螺杆菌诱导的胃癌细胞源性外泌体中差异表达miRNA的筛选及初步分析

目的:探讨幽门螺杆菌( H. pylori)诱导的人胃癌SGC-7901细胞源性外泌体中微小RNA(miRNA)的差异表达,为进一步阐明 H． pylori的致癌机制提供新线索。 方法:超高速离心法和试剂盒提取 H. pylori刺激组和...     

寨卡病毒感染人肝癌细胞HepG2后外泌体中差异miRNA分析

目的探索人肝癌细胞HepG2感染寨卡病毒(Zika virus, ZIKV)后的外泌体miRNA的表达差异, 对其靶基因进行预测、分析。方法以感染复数0.5的ZIKV(ZJ03株)感染HepG2, 以超速离心法提取、纯化感染2 d与未感染细胞的外泌体(Exo-ZIKV与Exo-NC)。以透射电镜观察外泌体形态, 纳米粒径分析检测外泌体粒径分布, Western blot检测外泌体标志蛋白质等方法鉴定。提取纯化外泌体小RNA, 进行miRNA测序与分析, 对部分差异表达miRNA采用实时定量PCR验证。生物信息方法分析差异miRNA靶基因。结果在透射电镜下呈杯托状双层膜小囊泡结构;粒径大小分布几乎一致但Exo-ZIKV浓度(5.24×108颗粒/ml )较Exo-NC(3.06×108 paritcle/ml)增多。Western blot检测出Hsp70、CD63和CD9蛋白表达, 测序分析显示共20个差异表达miRNA, 其中12个miRNA表达上调8个miRNA表达下调, 上调miRNA多与抗病毒通路相关, 差异表达miRNA对应的靶基因主要富集在嘧啶与嘌呤代谢等途径中。结论 ZI...     

Deep sequencing identifies deregulation of microRNAs involved with vincristine drug-resistance of colon cancer cells

Background: Vincristine (VCR) is a chemical that is widely used in tumor therapy. While long-term use can make tumor cells resistant to VCR, the underlying mechanisms of this resistance are still unclear. Objective: This study aimed at investigating the role of microRNA (miRNA) in colon cancer drug resistance. Methods: HCT-8 colon carcinoma cells were cultured and treated with different VCR concentrations to establish an HCT-8/VCR resistant cell line. Whole-genome screens, HiSeq 2500 sequencing, and bioinformatics methods were used to detect and analyze differences in miRNA expression between the drug-resistant HCT-8/VCR cells and non-resistant HCT-8 cells. Differential expression profiles of miRNAs were constructed based on sequencing result. Results: The HCT-8/VCR resistant colon carcinoma cell line was established. With regard to the difference in drug resistance between HCT-8/VCR and HCT-8 cells, 24 miRNAs showed statistically significant differences in their expression (fold change > 4), of which 17 were up-regulated. Seven miRNAs were down-regulated. Conclusion: As abnormal expression of miRNAs was associated with VCR resistance of colon carcinoma cells, differences in miRNA expression may play a key role in VCR resistance of colon cancer cells.     

RNA干扰技术抑制耐药细胞MDR1基因表达的研究

目的： 探讨载体表达的小干扰RNA (siRNA)抑制MDR1基因的表达，并逆转卵巢癌耐药细胞多药耐药的可行性。 方法： 浓度梯度诱导法和人MDR1基因载体转染法建立阿霉素耐药细胞株OVCAR/AR和多药耐药亚株OVCAR/MDR细胞。脂质体介导将MDR1特异性siRNA的表达载体(pSN/mdr1a和pSN/mdr1b)转染耐药细胞，实时定量RT-PCR方法检测MDRl mRNA的表达，流式细胞术检测P-gp的表达，MTT法检测耐药细胞对化疗药的抵抗性。 结果： 耐药细胞OVCAR/MDR细胞MDR1 mRNA的表达高于OVCAR/AR细胞，两者均高于其亲代细胞OVCAR-3；转染pSN/mdr1a和pSN/mdr1b可显著抑制两株耐药细胞MDR1 mRNA和P-gp的表达，OVCAR/MDR和OVCAR/AR细胞对阿霉素抗药性的逆转率分别为79.5%和93.9%。 结论： 载体表达的MDR1特异性siRNA可抑制卵巢癌耐药细胞亚株MDR1基因的表达，因而增加耐药细胞对化疗药物的敏感性。     

短发夹状RNA抑制GCS基因在人乳腺癌细胞的表达及逆转其多药耐药

目的构建葡萄糖神经酰胺合成酶(GCS)基因的短发夹状RNA(shRNA),观察其对人耐药乳腺癌细胞GCS表达的抑制及多药耐药的逆转作用。方法设计2对GCS基因编码的反向重复序列,中间间隔6个nt,体外合成并克隆至载体pSUPER。转染乳腺癌细胞,Westernblot和免疫细胞化学方法测定GCS表达。Westernblot、比色法检测细胞内caspase-3的表达,流式细胞仪分析细胞凋亡率。四氮唑盐(MTT)法检测半数细胞抑制浓度。结果酶切和DNA测序证实重组质粒构建成功。转染后GCS蛋白含量分别下降80%和82%,GCS表达阳性率降低为18·1%和16·7%。caspase-3表达和活性均显著增强,细胞凋亡率明显增加,细胞对化疗药物耐药性有明显下降。结论shRNA可有效抑制人耐药乳腺癌细胞中GCS表达,并可提高其对多种化疗药物的敏感性。     

Increased expression of P-glycoprotein and doxorubicin chemoresistance of metastatic breast cancer is regulated by miR-298

MicroRNAs (miRNAs) are short, noncoding RNA molecules that regulate the expression of a number of genes involved in cancer; therefore, they offer great diagnostic and therapeutic targets. We have developed doxorubicin-resistant and -sensitive metastatic human breast cancer cell lines (MDA-MB-231) to study the chemoresistant mechanisms regulated by miRNAs. We found that doxorubicin localized exclusively to the cytoplasm and was unable to reach the nuclei of resistant tumor cells because of the increased nuclear expression of MDR1/P-glycoprotein (P-gp). An miRNA array between doxorubicin-sensitive and -resistant breast cancer cells showed that reduced expression of miR-298 in doxorubicin-resistant human breast cancer cells was associated with increased expression of P-gp. In a transient transfection experiment, miR-298 directly bound to the MDR1 3' untranslated region and regulated the expression of firefly luciferase reporter in a dose-dependent manner. Overexpression of miR-298 down-regulated P-gp expression, increasing nuclear accumulation of doxorubicin and cytotoxicity in doxorubicin-resistant breast cancer cells. Furthermore, down-regulation of miR-298 increased P-gp expression and induced doxorubicin resistance in sensitive breast cancer cells. In summary, these results suggest that miR-298 directly modulates P-gp expression and is associated with the chemoresistant mechanisms of metastatic human breast cancer. Therefore, miR-298 has diagnostic and therapeutic potential for predicting doxorubicin chemoresistance in human breast cancer.     

Suppression of SPIN1‐mediated PI3K–Akt pathway by miR‐489 increases chemosensitivity in breast cancer

Drug resistance is one of the major obstacles for improving the prognosis of breast cancer patients. Increasing evidence has linked the association of aberrantly expressed microRNAs (miRNAs) with tumour development and progression as well as chemoresistance. Despite recent advances, there is still little known about the potential role and mechanism of miRNAs in breast cancer chemoresistance. Here we describe that 16 miRNAs were found to be significantly down‐regulated and 11 up‐regulated in drug‐resistant breast cancer tissues compared with drug‐sensitive tissues, using a miRNA microarray. The results also showed miR‐489 to be one of the most down‐regulated miRNAs in drug‐resistant tissues and cell lines, as confirmed by miRNA microarray screening and real‐time quantitative PCR. A decrease in miR‐489 expression was associated with chemoresistance as well as lymph node metastasis, increased tumour size, advanced pTNM stage and poor prognosis in breast cancer. Functional analysis revealed that miR‐489 increased breast cancer chemosensitivity and inhibited cell proliferation, migration and invasion, both in vitro and in vivo. Furthermore, SPIN1, VAV3, BCL2 and AKT3 were found to be direct targets of miR‐489. SPIN1 was significantly elevated in drug‐resistant and metastatic breast cancer tissues and inversely correlated with miR‐489 expression. High expression of SPIN1 was associated with higher histological grade, lymph node metastasis, advanced pTNM stage and positive progesterone receptor (PR) status. Increased SPIN1 expression enhanced cell migration and invasion, inhibited apoptosis and partially antagonized the effects of miR‐489 in breast cancer. PIK3CA, AKT, CREB1 and BCL2 in the PI3K–Akt signalling pathway, demonstrated to be elevated in drug‐resistant breast cancer tissues, were identified as downstream effectors of SPIN1. It was further found that either inhibition of SPIN1 or overexpression of miR‐489 suppressed the PI3K–Akt signalling pathway. These data indicate that miR‐489 could reverse the chemoresistance of breast cancer via the PI3K–Akt pathway by targeting SPIN1. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Emerging role of microRNAs in drug-resistant breast cancer

Intrinsic or acquired resistance to commonly used therapeutic agents is a major challenge in treating cancer patients. Decades of research have unraveled several unique and common mechanisms that could contribute to drug resistance in breast cancer. Recent studies unraveled the regulatory role of small noncoding RNA, designated as microRNA (miRNA), that were thought to be "junk" RNA in the past. Practically all aspects of cell physiology under normal and disease conditions were found to be regulated by miRNAs. In this review, we will discuss how miRNA profile is altered upon resistance development and the critical regulatory role miRNAs play in conferring resistance to commonly used therapeutic agents. It is hoped that further studies will lead to use of these differentially expressed miRNAs as prognostic and predictive markers, as well as novel therapeutic targets to overcome resistance.     

乳腺癌miRNAs表达谱的检测

目的检测人乳腺癌石蜡组织及人乳腺癌细胞株中miRNAs的表达情况,初步筛选人乳腺癌miRNAs表达谱。方法(1)应用组织微阵列平台,采用原位分子杂交技术对91例人乳腺癌和26例癌旁乳腺组织标本42种miRNA进行检测;(2)培养人乳腺癌细胞株MDA-MB-231和正常乳腺上皮细胞株HBL-100,分别抽提细胞总RNA,分离小分子RNA,荧光标记后与miRNAs微阵列杂交,通过芯片扫描和数据分析,获得人乳腺癌miRNAs表达谱。结果(1)与癌旁乳腺组织相比,14种miR-NAs在乳腺癌组织中的表达发生了显著变化(P0.05),其中9种表达上调,5种表达下调。(2)利用miRNAs微阵列,筛选获得71种与人乳腺癌相关miRNAs,与正常乳腺上皮细胞相比,34种miRNAs表达上调,37种表达下调。结论筛选出与乳腺癌相关的差异表达miRNAs,为进一步研究其在乳腺癌中的作用奠定基础。     

Increased expression of P-glycoprotein is associated with doxorubicin chemoresistance in the metastatic 4T1 breast cancer model

Development of drug resistance is one of the major causes of breast cancer treatment failure. The goal of this study was to understand the chemoresistance mechanism using the highly metastatic 4T1 breast cancer model, which emulates stage IV breast cancer in humans. The metastatic 4T1 breast cancer cell line treated with either doxorubicin or 5-FU showed a concentration-dependent reduced cell proliferation, with induced G2-phase growth arrest (doxorubicin) or G1-phase growth arrest (5-FU). Doxorubicin treatment partially suppressed the multiorgan metastasis of 4T1 breast cancer cells in the lung, heart, liver, and bone, compared with either 5-FU or cyclophosphamide. We isolated and characterized 4T1 breast cancer cells from doxorubicin-resistant metastatic tumors (cell line 4T1-R). Multiorgan metastasis of drug-resistant 4T1 breast tumors was totally resistant to doxorubicin treatment. Our results indicate that doxorubicin is localized exclusively in the cytoplasm of resistant 4T1 breast cancer cells and that it cannot reach the nucleus because of increased nuclear expression of P-glycoprotein. Pretreatment of doxorubicin-resistant 4T1-R breast cancer cells with verapamil, a general inhibitor of P-glycoprotein, increased nuclear translocation of doxorubicin and cellular cytotoxicity. Thus, impaired nuclear translocation of doxorubicin due to increased expression of P-glycoprotein is associated with doxorubicin resistance of highly metastatic 4T1 breast cancer.     

Alterations of microRNAs are associated with impaired growth of MCF-7 breast cancer cells induced by inhibition of casein kinase 2

Background and aim: Protein Kinase (casein kinase 2, CK2) is a pleiotropic serine-threonine kinase that is frequently dysregulated in many human tumors; microRNAs (miRNAs) are a class of small noncoding RNAs which play important roles in human cancers. This study aimed to investigate the role of CK2 and miRNA expression in breast cancer. Methods: Casein kinase 2 in MCF-7 breast cancer cell line was inhibited by the CK2 inhibitor TBB (4,5,6,7-tetrabromobenzotriazole), then cell proliferation was studied using MTT assay, and cell cycle distribution and apoptosis were detected by flow cytometry. The alteration of microRNAs expression profile was determined by microarray technology, followed by RT-PCR confirmation. Results: Here, we for the first time showed that inhibition of CK2 in MCF-7 breast cancer cells causes suppressed cell growth, which was related with dysregulation of the miRNA profile and altered expression. CK2 inhibition induced the up-regulated expression of 17 miRNAs and 10 down-regulated microRNAs which contributed to the impaired growth, inhibited cell cycle progress and increased apoptosis of MCF-7 cells by a CK2 inhibitor. Conclusions: These findings highlight the potential role of dysregulated miRNA expression regulated by CK2 in breast cancer.