ENTREP/FAM189A2 encodes a new ITCH ubiquitin ligase activator that is downregulated in breast cancer

The HECT‐type ubiquitin E3 ligases including ITCH regulate many aspects of cellular function through ubiquitinating various substrates. These ligases are known to be allosterically autoinhibited and to require an activator protein to fully achieve the ubiquitination of their substrates. Here we demonstrate that FAM189A2, a downregulated gene in breast cancer, encodes a new type of ITCH activator. FAM189A2 is a transmembrane protein harboring PPxY motifs, and the motifs mediate its association with and ubiquitination by ITCH. FAM189A2 also associates with Epsin and accumulates in early and late endosomes along with ITCH. Intriguingly, FAM189A2 facilitates the association of a chemokine receptor CXCR4 with ITCH and enhances ITCH‐mediated ubiquitination of CXCR4. FAM189A2‐knockout prohibits CXCL12‐induced endocytosis of CXCR4, thereby enhancing the effects of CXCL12 on the chemotaxis and mammosphere formation of breast cancer cells. In comparison to other activators or adaptors known in the previous studies, FAM189A2 is a unique activator for ITCH to desensitize CXCR4 activity, and we here propose that FAM189A2 be renamed as ENdosomal TRansmembrane binding with EPsin (ENTREP).     

The N-terminal polypeptide derived from vMIP-II exerts its antitumor activity in human breast cancer through CXCR4/miR-7-5p/Skp2 pathway

Breast cancer is a malignant tumor with the highest incidence in women of the world. CXCR4 and Skp2 are highly expressed in breast cancer cells and CXCR4 was positively correlated with Skp2 by interference or overexpression. The microRNA array was used to detect the differentially expressed spectrum of micro RNAs in breast cancer cells the changes of miR-7-5p after CXCR4 inhibitor (NT21MP) treatment to block the CXCR4/SDF-1 pathway was founded. MiR-7-5p has been found to be correlated with Skp2 in various tumors in the literature, and Skp2 expression can be regulated by transfection with miR-7-5p mimics or inhibitors. The expression level of miR-7-5p was upregulated or downregulated after CXCR4 interference or overexpression. Combined with the correlation between CXCR4 and miR-7-5p in the chip results, CXCR4 may regulate Skp2 through miR-7-5p. Epithelial cells have the morphological characteristics of mesenchymal cells for some reason called epithelial–mesenchymal transformation (EMT). Transfection of miR-7-5p mimics into drug-resistant cells reduced Skp2 levels, decreased the expression of Vimentin, Snail, and slug, and increased the expression of E-cadherin. CXCR4 inhibitor (NT21MP) can reverse the EMT changes caused by miR-7-5p inhibitor. Similarly, in vivo results suggesting that CXCR4 inhibitors can reverse the EMT phenotype of drug-resistant breast cancer cells through the CXCR4/miR-7-5p/Skp2 pathway. In summary, the CXCR4/miR-7-5p/Skp2 signaling pathway plays an important role in the progression of breast cancer. This study provides a theoretical basis for the treatment of breast cancer by targeting the CXCR4 pathway.     

Up-regulation of miR-21 mediates resistance to trastuzumab therapy for breast cancer

Trastuzumab resistance emerges to be a major issue in anti-human epidermal growth factor receptor 2 (HER2) therapy for breast cancers. Here, we demonstrated that miR-21 expression was up-regulated and its function was elevated in HER2(+) BT474, SKBR3, and MDA-MB-453 breast cancer cells that are induced to acquire trastuzumab resistance by long-term exposure to the antibody, whereas protein expression of the PTEN gene, a miR-21 target, was reduced. Blocking the action of miR-21 with antisense oligonucleotides re-sensitized the resistant cells to the therapeutic activities of trastuzumab by inducing growth arrest, proliferation inhibition, and G(1)-S cell cycle checking in the presence of the antibody. Ectopic expression of miR-21 in HER2(+) breast cancer cells confers resistance to trastuzumab. Rescuing PTEN expression with a p3XFLAG-PTEN-mut construct with deleted miR-21 targeting sequence at its 3' UTR restored the growth inhibition of trastuzumab in the resistant cells by inducing PTEN activation and AKT inhibition. In vivo, administering miR-21 antisense oligonucleotides restored trastuzumab sensitivity in the resistant breast cancer xenografts by inducing PTEN expression, whereas injection of miR-21 mimics conferred trastuzumab resistant in the sensitive breast tumors via PTEN silence. Up-regulatin of miR-21 in tumor biopsies obtained from patients receiving pre-operative trastuzumab therapy was associated with poor trastuzumab response. Therefore, miR-21 overexpression contributes to trastuzumab resistance in HER2(+) breast cancers and antagonizing miR-21 demonstrates therapeutic potential by sensitizing the malignancy to anti-HER2 treatment.     

Trastuzumab in the adjuvant treatment of HER2-positive early breast cancer patients: a meta-analysis of published randomized controlled trials

Background

Adjuvant trastuzumab therapy has yielded conflicting results for overall survival, concerns about central nervous system (CNS) metastasis, and questions about optimal schedule. Therefore, we carried out a meta-analysis to assess the benefits of concurrent or sequential trastuzumab with adjuvant chemotherapy for early breast cancer patients with HER2-positive tumors.

Methods

Computerized and manual searches were performed to identify randomized clinical trials comparing adjuvant chemotherapy with or without trastuzumab in HER2-positive early breast cancer patients. Odds ratios were used to estimate the association between the addition of trastuzumab to adjuvant chemotherapy and various survival outcomes. The fixed-effects or random-effects model was used to combine data.

Findings

With six eligible studies identified, this analysis demonstrated that patients with HER2-positive breast cancer derived benefit in disease-free survival, overall survival, locoregional recurrence and distant recurrence (all P<0.001) from the addition of trastuzumab to adjuvant chemotherapy, whereas trastuzumab did worse in CNS recurrence as compared to the control group (P = 0.018). Furthermore, concomitant use of trastuzumab significantly lowered the hazard of death (P<0.001) but bore a higher incidence of CNS recurrence (P = 0.010), while statistical significance failed to be discerned for either overall survival (P = 0.069) or CNS metastasis (P = 0.374) between the sequential and observation arms.

Conclusion

This analysis verifies the efficacy of trastuzumab in the adjuvant setting. Additionally, our findings indirectly corroborate the superiority of concurrent trastuzumab to sequential use and also illuminate that prolonged survival is the possible reason for the higher incidence of CNS with trastuzumab versus observation.     

Modulation of MicroRNA-194 and cell migration by HER2-targeting trastuzumab in breast cancer

Trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of the HER2 oncoprotein, can effectively target HER2-positive breast cancer through several mechanisms. Although the effects of trastuzumab on cancer cell proliferation, angiogenesis and apoptosis have been investigated in depth, the effect of trastuzumab on microRNA (miRNA) has not been extensively studied. We have performed miRNA microarray profiling before and after trastuzumab treatment in SKBr3 and BT474 human breast cancer cells that overexpress HER2. We found that trastuzumab treatment of SKBr3 cells significantly decreased five miRNAs and increased three others, whereas treatment of BT474 cells significantly decreased two miRNAs and increased nine. The only change in miRNA expression observed in both cell lines following trastuzumab treatment was upregulation of miRNA-194 (miR-194) that was further validated in vitro and in vivo. Forced expression of miR-194 in breast cancer cells that overexpress HER2 produced no effect on apoptosis, modest inhibition of proliferation, significant inhibition of cell migration/invasion in vitro and significant inhibition of xenograft growth in vivo. Conversely, knockdown of miR-194 promoted cell migration. Increased miR-194 expression markedly reduced levels of the cytoskeletal protein talin2 and specifically inhibited luciferase reporter activity of a talin2 wild-type 3'-untranslated region, but not that of a mutant reporter, indicating that talin2 is a direct downstream target of miR-194. Trastuzumab treatment inhibited breast cancer cell migration and reduced talin2 expression in vitro and in vivo. Knockdown of talin2 inhibited cell migration/invasion. Knockdown of trastuzumab-induced miR-194 expression with a miR-194 inhibitor compromised trastuzumab-inhibited cell migration in HER2-overexpressing breast cancer cells. Consequently, trastuzumab treatment upregulates miR-194 expression and may exert its cell migration-inhibitory effect through miR-194-mediated downregulation of cytoskeleton protein talin2 in HER2-overexpressing human breast cancer cells.     

乳腺癌CXCR1的表达特征及其与新辅助化疗疗效的相关性

目的:研究趋化因子受体CXCR1在乳腺癌组织中的表达特征,并探讨新辅助化疗前后其表达变化与化疗疗效的关系。方法:选取20例正常乳腺组织,20例乳腺纤维腺瘤,104例乳腺癌标本,免疫组化染色后统计每例标本CXCR1的阳性表达积分,分析不同乳腺疾病CXCR1的表达差异。统计新辅助化疗前后乳腺癌标本CXCR1的阳性表达积分的变化,分析其与化疗病理反应的关系。结果:CXCR1在正常乳腺组织、乳腺纤维腺瘤中低表达,在乳腺癌组织上高表达;其表达与患者的年龄、原发肿瘤的大小无关(P0.05),与病理分期、癌细胞的分化程度、淋巴结转移个数、激素受体状态及Her2表达情况相关,P0.05,有统计学意义。新辅助化疗后,癌组织中CXCR1的表达下降,下降幅度越大,其化疗疗效越好。结论:CXCR1的检测对于乳腺疾病的良恶性判断有指导意义,可辅助判断乳腺癌的恶性程度、侵袭性以及预后,CXCR1表达的下降与化疗疗效相关,抑制其表达可能可以提高化疗疗效。     

MicroRNA-21 as a predictor and prognostic factor for trastuzumab therapy in human epidermal growth factor receptor 2-positive metastatic breast cancer

Breast cancer is the second most common cancer diagnosed worldwide. Human epidermal growth factor receptor 2 (HER2)-positive breast cancer represents about 20% to 30% of all breast cancers. Trastuzumab is used in the treatment of HER2-positive breast cancer. MicroRNA-21 (miR-21) is an oncomiR that acts by inhibiting many tumor-suppressor genes. We analyzed the relative expression levels of serum miR-21 in 20 HER2-positive metastatic breast cancer patients before and after 3 months of treatment with trastuzumab. miR-21 levels decreased with a high significant difference after trastuzumab therapy (P = 0.001). Although miR-21 expression levels were lower in responders than in nonresponders, the difference was not statistically significant ( P = 0.6). Our results demonstrated a significant negative correlation between its basal expression, expression levels after treatment, and time to progression ( P = 0.03 and 0.01, respectively). These results make miR-21 a potential prognostic factor for HER2-positive metastatic breast cancer patients. Additionally, it can be an interesting potential target in therapy using antisense oligonucleotides for miR-21.     

HuR和PDGFC在乳腺癌组织中的表达及相关性分析

目的:探讨HuR和PDGFC在乳腺癌组织中的表达及相关性。方法:选取2008年至2009年80例手术切除并有完整的临床与病理资料的乳腺癌患者为研究对象,采用免疫组化法对乳腺癌组织中HuR和PDGFC的表达进行检测,并进行统计学分析。分析两者的表达与乳腺癌pTNM分期的关系,以及两者之间的相关性。结果:乳腺癌组织中HuR和PDGFC的表达均与pTNM分期有相关性(均P0.05),且两者的表达呈正相关(r=0.608,P0.05),具有统计学意义。结论:乳腺癌中HuR和PDGFC的高表达可能参与了乳腺癌的发生发展过程,有望影响乳腺癌的术后治疗。两者的表达产物呈正相关,HuR的表达产物可能通过对PDGFC的表达进行调控促进乳腺癌的发生与发展。     

Circulating MiR-125b as a marker predicting chemoresistance in breast cancer

Background

Chemotherapy is an important component in the treatment paradigm for breast cancers. However, the resistance of cancer cells to chemotherapeutic agents frequently results in the subsequent recurrence and metastasis. Identification of molecular markers to predict treatment outcome is therefore warranted. The aim of the present study was to evaluate whether expression of circulating microRNAs (miRNAs) can predict clinical outcome in breast cancer patients treated with adjuvant chemotherapy.

Methodology/Principal Findings

Circulating miRNAs in blood serum prior to treatment were determined by quantitative Real-Time PCR in 56 breast cancer patients with invasive ductal carcinoma and pre-operative neoadjuvant chemotherapy. Proliferating cell nuclear antigen (PCNA) immunostaining and TUNEL were performed in surgical samples to determine the effects of chemotherapy on cancer cell proliferation and apoptosis, respectively. Among the miRNAs tested, only miR-125b was significantly associated with therapeutic response, exhibiting higher expression level in non-responsive patients (n = 26, 46%; p = 0.008). In addition, breast cancers with high miR-125b expression had higher percentage of proliferating cells and lower percentage of apoptotic cells in the corresponding surgical specimens obtained after neoadjuvant chemotherapy. Increased resistance to anticancer drug was observed in vitro in breast cancer cells with ectopic miR-125b expression; conversely, reducing miR-125b level sensitized breast cancer cells to chemotherapy. Moreover, we demonstrated that the E2F3 was a direct target of miR-125b in breast cancer cells.

Conclusions/Significance

These data suggest that circulating miR-125b expression is associated with chemotherapeutic resistance of breast cancer. This finding has important implications in the development of targeted therapeutics for overcoming chemotherapeutic resistance in novel anti-cancer strategies.     

非小细胞肺癌组织MAGE-A3、HIF-1α、MTA1表达与临床病理参数及复发转移的关系研究

目的:探讨非小细胞肺癌组织黑色素瘤相关抗原-A3(MAGE-A3)、缺氧诱导因子-1α(HIF-1α)、转移相关蛋白1(MTA1)表达与临床病理参数及复发转移的关系。方法:选择2015年2月至2018年1月我院诊治的130例非小细胞肺癌患者进行临床研究,采用免疫组织化学染色法检测其非小细胞癌组织及癌旁组织中MAGE-A3、HIF-1α、MTA1的表达,分析MAGE-A3、HIF-1α、MTA1的表达与各项临床病理参数的关系。对比不同MAGE-A3、HIF-1α、MTA1表达情况患者的转移率及复发率。结果:130例非小细胞肺癌组织中MAGE-A3、HIF-1α、MTA1阳性率分别为70.77%、74.62%、79.23%,明显高于癌旁组织的25.38%、22.31%、17.69%(P<0.05)。非小细胞肺癌组织中MAGE-A3、HIF-1α、MTA1表达与淋巴结转移和TNM分期相关(P<0.05)。MAGE-A3、HIF-1α、MTA1阳性患者转移/复发率明显高于MAGE-A3、HIF-1α、MTA1阴性患者(P<0.05)。结论:MAGE-A3、HIF-1α、MTA1在非小细胞肺癌中阳性表达率升高,并且均与非小细胞肺癌淋巴结转移、TNM分期和转移复发相关,在非小细胞肺癌的诊断和预后评估中具有一定临床意义。     

血清HE4、VEGF、MCP-1及CCL20与乳腺癌患者保乳术后局部复发的关系研究

摘要 目的：探讨血清人附睾蛋白4（HE4）、血管内皮生长因子（VEGF）、单核细胞趋化因子-1（MCP-1）及CC趋化因子配体20（CCL20）与乳腺癌患者保乳术后局部复发的关系。方法：选择2015年7月~2018年7月期间本院收治的乳腺癌患者312例作为研究对象,均符合保乳术手术指征,成功实施乳腺癌保乳术,所有患者均随访3年。检测两组血清HE4、VEGF、MCP-1、CCL20水平情况,单因素及多因素Logistic回归分析影响术后局部复发的因素。使用受试者工作特征（ROC）曲线分析HE4、VEGF、MCP-1、CCL20水平单独及联合检测对保乳术后局部复发的预测价值。结果：随访过程中失访6例,剩余的306例患者根据随访结果,分为局部复发组27例、无局部复发组279例,局部复发率为8.82%。局部复发组的血清HE4、VEGF、MCP-1、CCL20水平均高于无局部复发组（P<0.05）。单因素分析结果显示,乳腺癌患者保乳术后局部复发与年龄、淋巴结转移、切缘状态、人表皮生长因子受体2（Her-2）、细胞增殖相关抗原（Ki-67）、术后规范化疗、术后足程放疗有关（P<0.05）。多因素Logistic回归分析结果显示术后规范化疗、年龄偏高、术后足程放疗是保乳术后局部复发的保护因素,HE4、VEGF、MCP-1、CCL20水平偏高,切缘状态、Her-2、Ki-67阳性以及淋巴结转移是保乳术后局部复发的危险因素（P<0.05）。HE4、VEGF、MCP-1、CCL20联合应用预测乳腺癌患者保乳术后局部复发的效能高于单一指标应用。结论：乳腺癌保乳术后局部复发患者体内HE4、VEGF、MCP-1、CCL20水平高表达,四指标联合检测可辅助预测保乳术后局部复发。且乳腺癌患者保乳术后复发还受到切缘状态、Her-2、Ki-67等多种因素的影响。     

MicroRNA-224 targets RKIP to control cell invasion and expression of metastasis genes in human breast cancer cells

The Raf kinase inhibitor protein (RKIP) is a tumor suppressor that protects against metastasis and genomic instability. RKIP is downregulated in many types of tumors, although the mechanism for this remains unknown. MicroRNAs silence target genes via translational inhibition or target mRNA degradation, and are thus important regulators of gene expression. In the current study, we found that miR-224 expression is significantly upregulated in breast cancer cell lines, and especially in highly invasive MDA-MB-231 cells, compared to human normal breast epithelial cells. In addition, miR-224 inhibits RKIP gene expression by directly targeting its 3'-untranslated region (3'-UTR). Moreover, metastasis, as assayed by Transwell migration, 3D growth in Matrigel, and wound healing, was enhanced by ectopic expression of miR-224 and inhibited by miR-224 downregulation. Promotion of metastasis in response to miR-224 downregulation was associated with derepression of the stroma-associated RKIP target genes, CXCR4, MMP1, and OPN, which are involved in breast tumor metastasis to the bone. Taken together, our data indicate that miR-224 play an important role in metastasis of human breast cancer cells to the bone by directly suppressing the RKIP tumor suppressor.     

曲妥珠单抗在HER-2阳性乳腺癌治疗中的研究进展

乳腺癌是女性最常见的恶性肿瘤之一,中国女性乳腺癌发病率逐年上升。人表皮生长因子受体2(human epidermal growth factor receptor-2,HER-2)在近三分之一的乳腺癌患者中呈现基因扩增或受体蛋白高表达。HER-2阳性的乳腺癌患者预后差,术后复发风险高、生存期短。曲妥珠单抗是人表皮生长因子受体-2的特异性抑制剂[1],在HER-2阳性乳腺癌患者的治疗中得到了广泛的应用,并且曲妥珠单抗分子靶向治疗相比于传统的化疗,具有特异性较强,毒副反应相对较小等优点。它改变了HER-2阳性乳腺癌患者的自然疾病进程,延长了患者的生存时间。本文将从四个方面对曲妥珠单抗在HER-2阳性乳腺癌患者治疗中的研究、应用及进展进行综述。