过表达miR-520d 通过抑制自噬蛋白Beclin1 逆转三阴性乳腺癌细胞化疗耐药性

[摘要] 目的：探讨miR-520d 通过调控自噬逆转三阴性乳腺癌（TNBC）细胞化疗耐药的作用及分子机制。方法：以人TNBC细胞系MDA-MB-231 和MDA-MB-468 为亲本株细胞构建多西他赛（Doc）耐药细胞株MDA-MB-231/Doc 和MDA-MB-468/Doc,实验分为空白组（亲本细胞）、对照组（耐药细胞组）和过表达miR-520d 组。用qPCR检测空白组和耐药细胞组细胞中miR-520d 的表达水平,MTT实验检测过表达miR-520d 的耐药细胞对Doc 的敏感性,MDC染色后荧光显微镜观察细胞中自噬小体的发生情况、共聚焦显微镜观察过表达miR-520d 的耐药细胞中自噬相关蛋白LC3 阳性的细胞数。用荧光素酶报告基因实验验证miR-520d 与Beclin1 的靶向关系。用WB实验检测过表达miR-520 对细胞中自噬相关蛋白Beclin1 和LC3Ⅰ、LC3Ⅱ表达的影响。结果：TNBC耐药细胞中miR-520d 的表达水平明显低于空白组细胞（P<0.01）。过表达miR-520d 的耐药细胞对Doc的敏感性显著提高（P<0.01）、细胞的自噬活性明显降低（P<0.01）。荧光素酶报告基因实验证明Beclin1 是miR-520d 可能的靶分子。Doc 与miR-520d mimics 联合使用可降低TNBC耐药细胞中LC3-Ⅱ/Ⅰ比值和自噬蛋白Beclin1 的表达水平（均P<0.05）。结论：通过调控miR-520d 水平可能改变自噬蛋白Beclin1 表达,从而逆转TNBC细胞Doc化疗耐药性。     

细胞自噬在肿瘤化疗耐药中的作用

自噬是一种进化上保守的溶酶体依赖的自身降解途径,不仅在保持基因组完整性和维持内环境稳定方面发挥重要作用,也与肿瘤的发生发展和肿瘤耐药密切相关。一方面,保护性自噬能够促进耐药细胞生存;另一方面,自噬作为程序性死亡机制能够直接促进耐药肿瘤细胞死亡。本文综述自噬在肿瘤细胞化疗耐药中的研究进展和相关的信号转导通路,为克服肿瘤多药耐药提供新思路。     

三阴性乳腺癌免疫治疗耐药机制的研究进展

目的 三阴性乳腺癌(Triple-negative breast cancer, TNBC)由于具有较高肿瘤突变负荷(TMB)和肿瘤浸润淋巴细胞,可受益于免疫治疗。尽管免疫治疗作为TNBC的重要治疗策略已取得突破,但最近的一些临床数据表明,很大一部分患者对免疫治疗表现出耐药,或对治疗有效果的患者出现进一步复发或进展。这些预后不良的主要原因是其复杂的内在或外在免疫逃逸机制,可能是由抗原呈递异常、免疫抑制性肿瘤微环境、与其他免疫检查点相互作用以及肿瘤细胞信号传导的异常激活引起的。然而目前对于TNBC免疫治疗耐药机制的研究尚不完善。本文将对免疫治疗所面临的挑战及TNBC对免疫治疗产生耐药性的潜在机制进行综述。     

miR-27a在三阴性乳腺癌中的表达及其对细胞耐药的影响

目的:探讨miR-27a在三阴性乳腺癌（triple-negative breast cancer,TNBC）中的表达及其对细胞耐药的影响。方法:首先通过QRT-PCR检测TNBC细胞株及非TNBC细胞株中miR-27a及P-gp的差异表达;上调TNBC细胞中的miR-27a的表达,通过CCK8检测细胞对化疗药物敏感性的变化。同时收集TNBC患者化疗前后血液标本,将其分为化疗敏感组和化疗耐药组,QRT-PCR检测患者血液标本中miR-27a及P-gp的表达,分析miR-27a与乳腺癌患者预后相关性。结果:miR-27a在TNBC细胞株中的表达明显低于非TNBC细胞株,上调TNBC细胞株中miR-27a的表达能够降低P-gp的表达,增加细胞对化疗药物的敏感性,此外TNBC组中miR-27a的表达与患者组织学分级、临床分期及淋巴结转移相关（P<0.05）;在非TNBC组中miR-27a的表达与患者临床病理特征无明显相关性（P均＞0.05）。结论:miR-27a参与调节TNBC细胞耐药,miR-27a可作为评估乳腺癌化疗敏感性及临床预后的潜在靶基因。     

乳腺癌组织中耐药基因和抑癌基因表达与化疗耐药的关系

乳腺癌是妇女最常见的恶性肿瘤，目前治疗的重要手段为手术及化疗，但一些患者在化疗前后对某些药物产生耐药性，导致化疗失败，严重影响化疗效果和肿瘤预后。研究发现．肿瘤细胞产生耐药的原因极其复杂。在肿瘤细胞产生耐药的机制中，除了P-gp的“药泵”之外．还存在有其他机制如胎盘型谷胱甘肽-S-转移酶-π(GST-π)的解毒作用增强、拓扑异构酶Ⅱ(topoisomerase Ⅱ)水平的降低以及MDR相关蛋白(multidrug resistance associated protein，MRP)表达等。     

三阴性乳腺癌组织中TOPK的表达及其与新辅助化疗治疗反应和预后的相关性

目的:探讨T-LAK细胞起源的蛋白激酶（TOPK）在三阴性乳腺癌（TNBC）组织中的表达和作用,研究TOPK表达与新辅助化疗（NACT）治疗反应和预后的关系。方法:收集66例采用多西他赛+表柔比星+环磷酰胺（TEC）NACT方案的TNBC患者治疗前后的组织学标本,用免疫组化的方法检测TOPK和Ki-67的表达,采用Miller-Payne（MP）系统评估治疗反应,并对患者的无进展生存期（PFS）进行生存分析。结果:MP分级较低（1-3级）的患者组织中的TOPK阳性率高于MP分级较高（4-5级）的患者,在NACT治疗中TOPK阳性患者的预后不佳。同时发现MP 1-3级患者在NACT后组织中TOPK表达升高,而MP 4-5级患者NACT后组织中TOPK表达降低。NACT治疗后组织中TOPK升高的患者的PFS较TOPK降低者差。接受者操作特性曲线（ROC）结果表明,NACT前后患者组织中TOPK表达变化对预后的评估准确性更高。结论:TNBC组织中TOPK水平高的患者对NACT治疗反应不佳,并且预后较差。TOPK表达水平可能提示TNBC的NACT治疗反应和预后。     

自噬与肿瘤化疗耐药关系的研究进展

自噬是一种自我降解的细胞过程,主要负责降解功能失调或不必要的蛋白质和细胞器,以维持细胞内稳态。近年来,肿瘤与自噬的关系一直颇受关注,越来越多的证据表明自噬在肿瘤发生发展及治疗中具有自相矛盾的作用。化疗是目前治疗癌症最有效的方法之一,与手术、放疗并称为癌症的三大治疗手段。但化疗过程中产生的获得性耐药已成为肿瘤治疗失败的首要原因。有研究表明,自噬是肿瘤化疗耐药的关键过程之一。本文就自噬与肿瘤化疗耐药的相关性及研究进展进行综述。     

三阴乳腺癌术后辅以密集化疗的临床疗效

目的：探讨三阴乳腺癌术后辅以剂量密集化疗的临床疗效。方法：选取2004年6月至2010年1月43例三阴乳腺癌患者随机分为治疗组（密集化疗组）和对照组（常规化疗组）。两组患者均采用盐酸吡柔比星（THP）50mg/ m2,d1,紫杉醇（TAX）175mg/ m2,d2。密集化疗组每14d 重复,而对照组每21d 重复。共6个周期。两组患者化疗结束后均给予患侧胸壁及同侧锁骨上放疗 DT 总=50Gy/（25f·5w）。结果：全部病例均按计划完成治疗,并随访60个月以上,随访率97.7%。密集化疗组与常规治疗组的3年无病生存率分别为60.9%和30.0%（P <0.05）。两组3年总生存率分别为78.0%和65.0%（P >0.05）。密集化疗组和常规化疗组的5年无病生存率及5年总生存率分别为13.0%、10.0%（P >0.05）和39.1%、30.0%（P >0.05）。但密集化疗组的无病生存期（DFS）为11~28个月,中位无病生存期（MDFS）为23.4个月,较常规化疗组无病生存期（10~25个月）及中位无病生存期（20.6个月）明显延长。两组在胃肠道反应、骨髓抑制及心脏毒性等毒副反应方面的发生率分别为47.8%、65.2%、47.8%和45.0%、55.0%、40.0%,均无显著性差异（P >0.05）。两组均无Ⅲ-Ⅳ度胃肠道反应及心脏毒性。结论：三阴乳腺癌术后辅以密集化疗能有效提高患者3年无病生存率,延长患者无病生存期,且相关毒副反应未明显增加。     

miRNA在乳腺癌化疗耐药中的作用

总结近期国内外有关miRNA在乳腺癌化疗耐药中作用的研究进展。应用Pubmed和CNKI期刊全文数据库检索系统以“miRNA、乳腺癌和化疗耐药”为关键词,检索2000年1月至2012年10月有关在乳腺癌化疗耐药中作用的文献。从乳腺癌化疗耐药入手,阐述乳腺癌化疗耐药的特点、机制,并着重对miRNA在乳腺癌化疗耐药中的作用进行分析。miRNA通过多种途径参与乳腺癌的化疗耐药。本文具体综述了一些以不同机制参与肿瘤耐药的miRNA,及其具体参与耐药的途径。探讨了血清miRNA作为肿瘤标记物的潜在临床利用性。结论:深入研究血清miRNA在乳腺癌耐药中的作用和机制,必将为乳腺癌的靶向治疗掀起一个新的篇章。      

三阴性乳腺癌化疗进展

三阴性乳腺癌作为乳腺癌的一种特殊亚型,对内分泌治疗和现有靶向治疗无效,并且通常复发较早、进展迅速、预后较差。现就三阴性乳腺癌的分子分型及其临床价值、化疗药物和化疗方案以及化疗和潜在的新靶点药物联合方面的最新进展作一综述。     

吉西他滨联合顺铂治疗耐药三阴性晚期乳腺癌的临床观察

目的　观察吉西他滨联合顺铂方案治疗ＥＲ、ＰＲ、ＨＥＲ-２均阴性对蒽环类耐药的晚期转移性乳腺癌的疗效和安全性。方法　３４例对蒽环或紫杉类耐药晚期转移性乳腺癌患者,经免疫组化证实ＥＲ、ＰＲ、ＨＥＲ-２均阴性,给予吉西他滨联合顺铂方案治疗,具体用药为：吉西他滨１０００ｍｇ／ｍ^２静脉滴注,第１,８天;顺铂２５ｍｇ／ｍ^２静脉滴注,第１～３天。２１天为１周期,至少２个周期,２周期后评价疗效和毒副反应。结果　３４例患者均可评价疗效,获完全缓解（ＣＲ）２例（５.９％）,部分缓解（ＰＲ）１２例（３５.３％）,稳定（ＳＤ）１４例（４１.２％）,进展（ＰＤ）６例（１７.６％）,总有效率（ＣＲ＋ＰＲ）为４１.２％;中位疾病进展时间为５.２个月。主要不良反应包括骨髓抑制和胃肠道反应,无化疗相关死亡。结论　吉西他滨联合顺铂方案对蒽环类或紫杉类耐药的转移性三阴性乳腺癌有较好的近期疗效,不良反应可耐受,是有效的解救方案之一。     

TRAIL induces apoptosis in triple-negative breast cancer cells with a mesenchymal phenotype

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in some but not all breast cancer cell lines. Breast cancers can be divided into those which express the estrogen (ER) and progesterone (PR) receptors, those with HER-2 amplification, and those without expression of ER, PR, or HER-2 amplification (referred to as basal or triple-negative breast cancer). We tested a panel of 20 breast cancer cell lines representing the different types of breast cancer to evaluate if the molecular phenotype of the breast cancer cells determined their response to TRAIL. The most striking finding was that eight of eleven triple-negative cell lines are sensitive to TRAIL-mediated apoptosis. The eight TRAIL-sensitive triple-negative cell lines have a mesenchymal phenotype while the three TRAIL-resistant triple-negative cell lines have an epithelial phenotype. Two of five cell lines with HER-2 amplification were sensitive to TRAIL and none of the five ER positive cell lines were sensitive. RNAi-mediated knockdown of TRAIL receptor expression demonstrated that TRAIL Receptor 2 (TRAIL-R2) mediates the effects of TRAIL, even when both TRAIL-R1 and TRAIL-R2 are expressed. Finally, inhibition of EGFR, expressed in both TRAIL-sensitive and TRAIL-resistant triple-negative breast cancer cell lines, using a small molecule tyrosine kinase inhibitor (AG1478), enhanced TRAIL-induced apoptosis in TRAIL-sensitive cell lines but did not convert resistant cells into TRAIL-sensitive cells. Together, these findings suggest that a subset of triple-negative breast cancer, those with mesenchymal features, may be the most likely to benefit from TRAIL targeted therapy. These findings could form the basis to select breast cancer patients for clinical trials of TRAIL-R2 ligands. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. S. R. Davis and J. G. Pumphrey contributed equally to this work.     

三阴乳腺癌化疗的研究进展

三阴乳腺癌(TNBC)因浸润性较强是乳腺癌中预后不佳的一种亚型,其治疗已受到广泛关注,但尚无明确的标准.TNBC在新辅助化疗中可获得12％～48％的病理完全反应率(pCR),高于其他类型乳腺癌,但其pCR在文献报道中波动幅度较大.辅助化疗在早期TNBC中的应用仍存在争议,有学者主张使用不含蒽环类药物的化疗方案.紫杉类、蒽环类等细胞毒性药物仍是目前TNBC解救化疗的主力药物,临床试验显示,联合应用吉西他滨或卡培他滨可延长患者生存期.ADP-核糖聚合酶(PARP)成为TNBC靶向治疗新的研究靶点,对其抑制剂如BSI-201和Olaparib的深入研究有望为临床治疗提供更多有效的选择.     

Nab-paclitaxel for the treatment of triple-negative breast cancer: Rationale,clinical data and future perspectives

Triple-negative breast cancer (TNBC) accounts for ∼10–20% of breast cancers and is associated with relatively poor prognosis, earlier disease recurrence and higher number of visceral metastases. Despite an increasing understanding of the molecular heterogeneity of TNBC, clinical trials of targeted agents have thus far been disappointing; chemotherapy, in particular with anthracycline and taxanes, remains the backbone medical management for both early and metastatic TNBC. Nab-paclitaxel is a solvent-free, albumin-bound, nanoparticle formulation of paclitaxel and represents a novel formulation of an established, effective chemotherapeutic agent. Nab-paclitaxel has been specifically designed to overcome the limitations of conventional taxane formulations, including the barriers to effective drug delivery of highly lipophilic agents. It has shown significant efficacy and better tolerability than conventional taxanes in metastatic breast cancer and is approved for use in this setting. Increasing evidence suggests that nab-paclitaxel is effective in patients with more aggressive tumours, as seen in TNBC. Indeed, results of Phase II/III studies indicate that nab-paclitaxel may be effective as neoadjuvant treatment of TNBC. This article reviews the rationale and evidence supporting a role for nab-paclitaxel in the treatment of TNBC, including ongoing studies such as ADAPT-TN and tnAcity. In addition, the article reviews ongoing research into targeted therapies and immuno-oncology for the treatment of TNBC, and explores the potential role, current evidence and ongoing studies of nab-paclitaxel as the chemotherapy partner in combination with immunotherapy, where the unique properties of this taxane, including the lack of requirement for steroid pre-medication, may present an advantage.     

三阴性乳腺癌靶向治疗最新进展

三阴性乳腺癌(triple-negative breast cancer,TNBC)是一种特殊类型的乳腺癌,占乳腺癌总确诊的15%~20%。其雌激素受体(estrogen receptor,ER)、孕激素受体(progesterone receptor,PR)和人表皮生长因子受体(human epidermal growth factor receptor-2,HER-2)表达均阴性,具有独特的生物学特性和临床病理特征,肿瘤异质性很高,临床上具有复发高、转移早和预后差等特点。目前,临床上缺少有效的治疗手段。该综述介绍了TNBC的临床病理特征、分子亚型、几条重要的通路和靶点,以及目前各靶向药物临床试验研究进度,希望为今后TNBC的治疗提供新的临床思路。     

单细胞测序在三阴性乳腺癌新辅助化疗中的应用研究进展

三阴性乳腺癌是最具侵袭性、恶性程度最高的乳腺癌类型,目前多采用以化疗为主的综合治疗方案,新辅助化疗在其中发挥重要作用,但近半数患者会出现耐药,而具体机制尚不明确.单细胞测序技术能够在单个细胞基础上精准评估肿瘤发生、发展过程中基因组、转录组和表观遗传学信息的改变,为明确诊断肿瘤亚型、了解肿瘤耐药机制、发现治疗新靶点、评估...     

FGF13 promotes metastasis of triple-negative breast cancer

Triple-negative breast cancer (TNBC) represents 10–20% of all human ductal adenocarcinomas and has a poor prognosis relative to other subtypes, due to the high propensity to develop distant metastases. Hence, new molecular targets for therapeutic intervention are needed for TNBC. We recently conducted a rigorous phenotypic and genomic characterization of four isogenic populations of MDA-MB-231 human triple-negative breast cancer cells that possess a range of intrinsic spontaneous metastatic capacities in vivo, ranging from nonmetastatic (MDA-MB-231_ATCC) to highly metastatic to lung, liver, spleen and spine (MDA-MB-231_HM). Gene expression profiling of primary tumours by RNA-Seq identified the fibroblast growth factor homologous factor, FGF13, as highly upregulated in aggressively metastatic MDA-MB-231_HM tumours. Clinically, higher FGF13 mRNA expression was associated with significantly worse relapse free survival in both luminal A and basal-like human breast cancers but was not associated with other clinical variables and was not upregulated in primary tumours relative to normal mammary gland. Stable FGF13 depletion restricted in vitro colony forming ability in MDA-MB-231_HM TNBC cells but not in oestrogen receptor (ER)-positive MCF-7 or MDA-MB-361 cells. However, despite augmenting MDA-MB-231_HM cell migration and invasion in vitro, FGF13 suppression almost completely blocked the spontaneous metastasis of MDA-MB-231_HM orthotopic xenografts to both lung and liver while having negligible impact on primary tumour growth. Together, these data indicate that FGF13 may represent a therapeutic target for blocking metastatic outgrowth of certain TNBCs. Further evaluation of the roles of individual FGF13 protein isoforms in progression of the different subtypes of breast cancer is warranted.     

三阴性乳腺癌放射治疗相关机制的研究进展

放射治疗是乳腺癌局部治疗的主要手段之一。三阴性乳腺癌(triple-negative breast cancer,TNBC)作为乳腺癌分子亚型的一个分型,其分子及生物学行为具有多方面特殊性,并存在多个分子靶点的异常,这些异常分子靶点可通过不同机制影响肿瘤对电离辐射的反应,从而调节三阴性乳腺癌的放疗敏感性。现就TNBC的放射治疗及其放疗敏感性相关分子靶点的研究新进展予以综述。     

Role of tumor microenvironment in triple-negative breast cancer and its prognostic significance

Breast cancer has been shown to live in the tumor microenvironment,which consists of not only breast cancer cells themselves but also a significant amount of pathophysiologically altered surrounding stroma and cells.Diverse components of the breast cancer microenvironment,such as suppressive immune cells,re-programmed fibroblast cells,altered extracellular matrix (ECM) and certain soluble factors,synergistically impede an effective anti-tumor response and promote breast cancer progression and metastasis.Among these components,stromal cells in the breast cancer microenvironment are characterized by molecular alterations and aberrant signaling pathways,whereas the ECM features biochemical and biomechanical changes.However,triple-negative breast cancer (TNBC),the most aggressive subtype of this disease that lacks effective therapies available for other subtypes,is considered to feature a unique microenvironment distinct from that of other subtypes,especially compared to Luminal A subtype.Because these changes are now considered to significantly impact breast cancer development and progression,these unique alterations may serve as promising prognostic factors of clinical outcome or potential therapeutic targets for the treatment of TNBC.In this review,we focus on the composition of the TNBC microenvironment,concomitant distinct biological alteration,specific interplay between various cell types and TNBC cells,and the prognostic implications of these findings.     

Targeting triple-negative breast cancer: A clinical perspective

Triple-negative breast cancer (TNBC) is a disease with often an aggressive course and a poor prognosis compared to other subtypes of breast cancer. TNBC accounts for approximately 10%–15% of all diagnosed breast cancer cases and represents a high unmet need in the field. Up to just a few years ago, chemotherapy was the only systemic treatment option for this subtype (1). To date, TNBC is considered a heterogeneous disease. One of the existing classifications is based on the analysis of mRNA expression in 587 TNBC cases, in which Lehman et al. proposed six subtypes of TNBC as follows: two basal-like (BL1 and BL2) subtypes, a mesenchymal (M) subtype, a mesenchymal stem-like (MSL) subtype, an immunomodulatory (IM) subtype, and a luminal androgen receptor (LAR) subtype (2). Later studies have demonstrated that the IM and MSL subtypes do not correlate with independent subtypes but reflect background expression by dense infiltration of tumor-infiltrating lymphocytes (TILs) or stromal cells. According to this finding, the classification of TNBC has been revised into the following four subtypes: basal 1, basal 2, LAR, and mesenchymal subtypes (3). Over the last years, several new strategies have been investigated for the treatment of patients with TNBC. Among them, immunotherapy, antibody drug conjugates, new chemotherapy agents, and targeted therapy have been and are currently being developed. The present article aims to provide an updated overview on the different treatment options that are now available or are still under investigation for patients with TNBC.