Hippo信号通路在乳腺癌转移中的作用

Hippo是新发现的一种非常保守的信号传导通路,其主要成分在多种癌症中出现突变和表达失调,促进了恶性肿瘤的发生发展。但有关Hippo信号通路在乳腺癌中的研究较少,分子调控机制尚不完全清楚。现就Hippo信号通路在乳腺癌转移中的作用进行综述,以期明确Hippo信号通路对乳腺癌发生、发展和转移可能起到的作用,为抑制乳腺癌的转移提供新思路。     

Hippo信号通路在肺癌中的研究进展

肺癌是全世界范围内肿瘤相关性死亡的首要原因,每年死亡人数超过100万人,占全球癌症死亡人数的五分之一.虽然目前在手术、放化疗、靶向治疗、免疫治疗肺癌方面取得了一定进展,但患者的预后仍不理想.因此,亟待寻找评价预后的分子标志物和肺癌的治疗新靶点,为肺癌患者提供生存获益的有效方法.近年来,Hippo信号通路逐渐成为国内外肿瘤研究领域中新兴且热门的研究方向.Hippo信号通路激活时,其核心组件MST/MOB、LATS 1/2等能抑制转录的共激活剂YAP/TAZ的转录,二者被磷酸化并滞留在细胞浆中,从而抑制肺癌的发生发展.因此Hippo信号通路在临床应用中的潜在价值也越来越受关注.本篇文章总结了Hippo信号通路核心组成元件及上下游调控因子在肺癌形成进展过程中的重要作用和分子机制,并对Hippo信号通路的研究前景进行展望.     

Hippo通路与乳腺癌发生发展的作用研究进展与应用前景

在发病率逐年增高和死亡率居高不下的全球大背景下,乳腺癌一直是科研领域的研究热点。Hippo通路广泛涉及了从乳腺正常发育至乳腺癌发生发展、侵袭转移及耐药等一系列过程。该综述以乳腺癌总人群发病特征及Hippo通路发展历程为背景,围绕肿瘤干细胞、上皮-间质转化及凋亡三方面介绍了Hippo通路对乳腺癌肿瘤表型的调控,最后从临床应用前景上做出展望,介绍了Hippo通路成分对乳腺癌患者的预后作用及可能提供的药物治疗靶点。     

乳腺癌干细胞的治疗抵抗及其信号通路

乳腺癌干细胞是导致乳腺癌治疗失败的主要原因,其在乳腺癌进展及复发耐药过程中发挥重要作用,与乳腺癌的放化疗、内分泌治疗抵抗等密切相关.其转移潜能及治疗抵抗与上皮间质转化及Hedgehog、Wnt、白细胞介素-6/信号传导与转录激活因子3、转化生长因子-β等多种信号通路相关,而针对这些信号通路的部分靶向药物也正进行临床转化研究,有望为乳腺癌的临床治疗提供新的方法.     

转录因子TEAD4 在肿瘤发生发展及治疗中的作用

[摘要] TEA转录因子4（TEAD4）是Hippo 信号通路中转录共激活子YAP/TAZ下游最重要的转录因子TEAD家族的成员之一。近年来,TEAD4 的促癌作用被逐渐发现,其可与YAP形成转录复合体或不依赖于YAP独立调控下游相关靶基因的表达,在胃肠道肿瘤、肝癌、肺癌、乳腺癌等多种人类实体肿瘤中发挥促癌作用,导致肿瘤的发生和进展,并且是多种肿瘤不良预后的标志。此外,靶向TEAD4 及以阻断YAP-TEAD4 结合为靶点的药物在多种肿瘤的体外实验及动物模型中取得显著的治疗效果,提示TEAD4 可能是肿瘤治疗的一个理想靶点。本文就目前TEAD4 在肿瘤发生、发展及治疗中的研究现状作一总结及展望,以期为TEAD4的后续研究及以其为靶点的肿瘤治疗提供新思路。     

Hippo-YAP/TAZ信号通路调控铁死亡对肿瘤影响的研究进展

铁死亡是一种新型的铁依赖的程序性细胞死亡，常伴随脂质过氧化物的异常累积。Hippo 通路是一种高度进化保守的蛋白激酶信号通路，通过调节下游效应蛋白YAP/TAZ的亚细胞定位和蛋白稳定性，参与调节细胞的多种生命活动，包括组织生长、干细胞分化、肿瘤的发生发展等。近年来的研究发现，Hippo-YAP/TAZ信号通路通过细胞密度、细胞接触、细胞代谢、机械信号等多种细胞外途径影响肿瘤细胞对铁死亡的敏感性，在不同类型的肿瘤组织中通过特定的刺激条件、铁死亡靶向蛋白及其分子机制，影响泌尿、生殖、消化、呼吸和内分泌系统等肿瘤的发生和发展。Hippo-YAP/TAZ信号通路作为铁死亡新的调节机制，其激活为转移性及耐药性肿瘤的治疗提供了新的思路和方向。     

Wnt信号通路与乳腺癌

Wnt信号通路在某些肿瘤的发生中具有重要的作用，全文主要论述Wnt信号通路与乳腺癌之间的关系及目前针对Wnt信号通路所开展的乳腺癌相关研究。     

YAP/TAZ在肾细胞癌发生发展中作用及其机制的研究进展

肾癌是泌尿系统最常见的肿瘤之一，早期临床表现不典型，经手术治疗后仍有部分发生复发和转移，病死率高。因此，肾癌的早期诊断和晚期治疗成为亟待解决的两大问题。以YAP/TAZ为核心的Hippo 通路在肾癌的发生发展中发挥着重要作用，YAP/TAZ通过直接调控肾癌细胞的转录活性、内源性竞争RNA（ceRNA）机制、促进血管形成、增强肾细胞铁死亡敏感性以及作为肾癌细胞中其他信号通路的转导枢纽等多种机制，促进肾癌细胞的侵袭、转移和耐药；除此之外，YAP/TAZ在多种罕见的肾癌组织学亚型中起到指导分型和预测预后的作用。对于YAP/TAZ在肾癌中的作用及其机制的认识可为临床肾癌的早期诊断和晚期治疗提供理论参考依据。     

乳腺癌TGF-β信号通路相关转录因子研究进展

目的 总结与转化生长因子β(transforming growth factor-β,TGF-β)信号通路相关的转录因子在乳腺癌发生发展过程中的作用,分析它们与TGF-β信号通路之间的网络调控机制.方法 应用PubMed及CNKI期刊全文数据库检索系统,以“乳腺癌、转录因子和TGF-β”等为关键词,检索2011-01-01-2015-12 31的相关文献.纳入标准:(1)乳腺癌侵袭转移;(2)转录因子与TGF-β信号通路存在联系.剔除标准:(1)未阐明转录因子与TGF-β信号通路作用的具体机制;(2)实验设计不严谨.符合纳入标准的英文文献146篇,中文文献35篇,根据剔除标准剔除英文文献50篇,中文文献34篇,最后纳入分析文献88篇.结果 TGF-β信号通路是一条极为重要的细胞内信号转导途径,能调控细胞增殖、分化、迁移、粘附及凋亡等生理活动.在乳腺癌中,TGF-β信号通路起着双重作用,即在肿瘤发生的早期阶段,TGF-β信号通路起着一种预防性或肿瘤抑制的作用,但随着肿瘤的发展,TGF-β能够通过影响肿瘤微环境、增强侵袭性及抑制免疫细胞功能来促进肿瘤细胞的转移.多个转录因子c-Myc、p53、C/EBPβ、14-3-3ξ、Blimp-1、Oct-4和Nanog、Foxq1、TBX3、FOXM1、GATA3、HOXB9、Six1、Pokemon、Snail、Slug和SOX4已证实与TGF-β信号通路发生相互作用,共同参与调控乳腺癌发生发展过程.结论 乳腺癌发生过程中转录因子与TGF-β信号通路形成复杂的调控网络,对乳腺癌的进程起着双向调节作用.     

MicroRNA-125a influences breast cancer stem cells by targeting leukemia inhibitory factor receptor which regulates the hippo signaling pathway

Cancer stem cells (CSC) are the main driving force behind cancer initiation and progression. The molecular mechanisms that regulate CSC properties are poorly understood. MicroRNAs (miRNAs) play a significant role in normal and cancer tissues. Here, we show that miRNA-125a indirectly regulates TAZ, an effector molecule in the Hippo pathway, through the leukemia inhibitory factor receptor (LIFR). The miR-125a→LIFR axis affected the homeostasis of nonmalignant and malignant breast epithelial stem cells through the Hippo signaling pathway. Inhibition of miR-125a in breast cancer cells led to a significant reduction in the CSC pool. In contrast, enhanced expression of miR-125a in nonmalignant breast epithelial cells resulted in significant expansion of the stem cell pool. Gain of function and loss of function of LIFR directly correlated with the inhibition and overexpression of miR-125a, respectively. Modulation of miR-125a led to a change in the activity of TAZ and its subcellular localization. We further demonstrated that miR-125a influenced stem cells by regulating Hippo signaling through LIFR in human primary breast cancer cells confirming the data obtained from established cell lines. We suggest that miR-125a could be a potential target against CSCs that maybe used along with the existing conventional therapies.     

YAP-Hippo signalling downstream of leukemia inhibitory factor receptor: implications for breast cancer

The proto-oncogenes YAP and TAZ have previously gained much attention as downstream effectors of Hippo tumour suppressor signalling. While the regulation of YAP/TAZ by MST/LATS kinases is reasonably well understood, the nature of factors functioning upstream of MST/LATS is yet to be elucidated in detail. A recent paper by Ma and co-workers defines a novel role for leukemia inhibitory factor receptor (LIFR) signalling upstream of the Hippo-YAP pathway in breast cancer metastasis. Moreover, a whole genome in vivo RNA interference screen by Lippmann and colleagues identified LIFR as a breast tumour suppressor. Here, we discuss the implications of these studies for breast cancer research and treatment.     

A novel HMGA1-CCNE2-YAP axis regulates breast cancer aggressiveness

High Mobility Group A1 (HMGA1) is an architectural chromatin factor that promotes neoplastic transformation and progression. However, the mechanism by which HMGA1 exerts its oncogenic function is not fully understood. Here, we show that cyclin E2 (CCNE2) acts downstream of HMGA1 to regulate the motility and invasiveness of basal-like breast cancer cells by promoting the nuclear localization and activity of YAP, the downstream mediator of the Hippo pathway. Mechanistically, the activity of MST1/2 and LATS1/2, the core kinases of the Hippo pathway, are required for the HMGA1- and CCNE2-mediated regulation of YAP localization. In breast cancer patients, high levels of HMGA1 and CCNE2 expression are associated with the YAP/TAZ signature, supporting this connection. Moreover, we provide evidence that CDK inhibitors induce the translocation of YAP from the nucleus to the cytoplasm, resulting in a decrease in its activity. These findings reveal an association between HMGA1 and the Hippo pathway that is relevant to stem cell biology, tissue homeostasis, and cancer.     

The Hippo transducer TAZ as a biomarker of pathological complete response in HER2-positive breast cancer patients treated with trastuzumab-based neoadjuvant therapy

Activation of the Hippo transducer TAZ is emerging as a novel oncogenic route in breast cancer and it has been associated with breast cancer stem cells. Additionally, TAZ expression has been linked with HER-2 positivity. We investigated the association between TAZ expression and pathological complete response in HER2-positive breast cancer patients treated with trastuzumab-based neoadjuvant therapy. TAZ was assessed in diagnostic core biopsies by immunohistochemistry. To categorize samples with low TAZ and samples with high TAZ we generated a score by combining staining intensity and cellular localization. The pathological complete response rate was 78.6% in patients with low TAZ tumors and 57.6% in patients with high TAZ tumors (p=0.082). In HER2-enriched tumors there was no significant association between TAZ and pathological complete response, whereas in the luminal B subtype the pathological complete response rate was 82.4% in tumors with low TAZ and 44.4% in tumors with high TAZ (p=0.035). This association remained statistically significant when restricting our analysis to triple-positive tumors with expression of both estrogen receptor and progesterone receptor ≥ 50% (p=0.035). Results from this exploratory study suggest that the TAZ score efficiently predicts pathological complete response in Luminal B, HER2-positive breast cancer patients who received neoadjuvant chemotherapy and trastuzumab.     

Hippo‐YAP signaling pathway: A new paradigm for cancer therapy

In the past decades, the Hippo signaling pathway has been delineated and shown to play multiple roles in the control of organ size in both Drosophila and mammals. In mammals, the Hippo pathway is a kinase cascade leading from Mst1/2 to YAP and its paralog TAZ. Several studies have demonstrated that YAP/TAZ is a candidate oncogene and that other members of the Hippo pathway are tumor suppressive genes. The dysregulation of the Hippo pathway has been observed in a variety of cancers. This review chronicles the recent progress in elucidating the function of Hippo signaling in tumorigenesis and provide a rich source of potential targets for cancer therapy.     

ZNF213 negatively controls triple negative breast cancer progression via Hippo/YAP signaling

Breast cancer is one of the most commonly diagnosed malignancies worldwide, while the triple negative breast cancer (TNBC) is the most aggressive and virulent subtype in breast cancers. Compared with luminal type breast cancers, which could be well controlled by endocrine treatment, TNBC is worse in prognosis and lack of effective targeted therapy. Thus, it would be interesting and meaningful to identify novel therapeutic targets for TNBC treatments. Recent genomic data showed the activation of Hippo/YAP signaling in TNBC, indicating its critical roles in TNBC carcinogenesis and cancer progression. Hippo/YAP signaling could subject to several kinds of protein modifications, including ubiquitination and phosphorylation. Quite a few studies have demonstrated these modifications, which controlled YAP protein stability and turnover, played critical role in Hippo signaling activation In our current study, we identified ZNF213 as a negative modifier for Hippo/YAP axis. ZNF213 depletion promoted TNBC cell migration and invasion, which could be rescued by further YAP silencing. ZNF213 knocking down facilitated YAP protein stability and Hippo target gene expression, including CTGF and CYR61. Further mechanism studies demonstrated that ZNF213 associated with YAP and facilitated YAP K48-linked poly-ubiquitination at several YAP lysine sites (K252, K254, K321 and K497). Besides, the clinical data showed that ZNF213 negatively correlated with YAP protein level and Hippo target gene expression in TNBC samples. ZNF213 expression correlated with good prognosis in TNBC patients. Our data provided novel insights in YAP proteolytic regulation and TNBC progression.     

Harmine suppresses breast cancer cell migration and invasion by regulating TAZ-mediated epithelial-mesenchymal transition

Breast cancer is a highly lethal disease due to cancer metastasis. Harmine (HM), a β-carboline alkaloid, is present in various medicinal plants. Our previous study demonstrated that HM suppresses cell proliferation and migration by regulating TAZ in breast cancer cells and accelerates apoptosis. Epithelial-mesenchymal transition (EMT) plays an important role in the development of breast cancer by inducing the characteristics of cancer stem cells, cancer metastasis and recurrence. Overexpression of TAZ was shown to mediate EMT in breast cancer cells. We aimed to investigate whether HM inhibits EMT and metastasis of breast cancer cells by targeting TAZ. In this study, the cells treated with HM or with downregulated expression of TAZ showed an increase in epithelial markers and decrease in mesenchymal markers in breast cancer cells. Consistently, the breast cancer cells treated with HM or with downregulated expression of TAZ showed suppressed migration and proliferation. Moreover, TAZ overexpression reversed EMT and metastasis induced by HM in breast cancer cells. Thus, HM suppresses EMT and metastasis and invasion by targeting TAZ in breast cancer cells. HM can be used as an anticancer drug for breast cancer treatment and chemoprevention.