PI3K/AKT/mTOR信号通路介导乳腺癌内分泌治疗耐药的研究进展

内分泌治疗在激素受体阳性乳腺癌患者中的地位越来越受到重视,可以明显改善患者预后.内分泌治疗耐药严重制约着其临床应用,但耐药机制仍不明确,目前认为多信号通路激活参与耐药形成,其中PI3K/AKT/mTOR信号通路在耐药机制中发挥重要作用.临床试验提示,在内分泌治疗的基础上阻断信号通路可以逆转耐药,研究结果令人鼓舞.本文对PI3K/AKT/mTOR信号通路在内分泌耐药机制中的作用进行综述.     

三阴性乳腺癌中PI3K/AKT/mTOR信号通路的突变及相关靶向治疗的研究进展

三阴性乳腺癌（TNBC）是最具侵袭性的乳腺癌亚型,PI3K/AKT/mTOR信号通路失调是TNBC最常见的致癌突变之一,靶向PI3K/AKT/mTOR信号通路是治疗TNBC的重要方向。本文着重介绍了PI3K/AKT/mTOR信号通路的机制,TNBC中出现的PIK3CA、AKT1或mTOR的突变,以及失活张力PTEN、PIK3R1或INPP4B的突变或丢失,也展现了布帕尼西、帕他色替、依维莫司等PI3K/AKT/mTOR信号通路靶向药物在治疗TNBC中单独、联合应用和与化疗或免疫疗法联用的疗效,同时论述了目前正在进行的各类临床试验及其未来的前景。     

乳腺癌分子靶向治疗现状

近年来,乳腺癌的分子靶向治疗取得了长足的发展.曲妥珠单抗联合化疗已成为Her-2阳性乳腺癌患者的标准一线治疗.全文从抗Her-2治疗药物-PI3K/AKT/mTOR通路中的抑制剂,抗血管生成治疗药物,针对BR-CA1/2突变的PARP抑制剂,细胞周期蛋白依赖性激酶4和6(CDK4/6)抑制剂几个方面就当前乳腺癌分子靶向治疗现状作一综述.     

PI3K/AKT/mTOR信号通路介导索拉非尼治疗原发性肝癌耐药机制的研究进展

索拉非尼（sorafenib）作为原发性肝癌（hepatocellular carcinoma,HCC）靶向治疗的一线药物已广泛应用于临床,然而部分HCC患者对索拉非尼治疗耐药导致临床疗效欠佳,联合其他靶向药物的临床实验仍未取得突破,故深入研究索拉非尼耐药机制,逆转索拉非尼耐药对于改善肝癌治疗的预后具有重要意义。最新研究发现,PI3K/AKT/mTOR信号通路在索拉非尼耐药机制中起重要作用,本文将从PI3K/AKT/mTOR信号通路促进肿瘤血管生成、参与细胞自噬、抑制肿瘤细胞凋亡并促进其增殖、与RAS/RAF/ERK/MEK信号通路交联及其促进上皮-间质转化等几个方面,概述其在索拉非尼治疗原发性肝癌时产生耐药的机制,为进一步开发治疗原发性肝癌的新型药物提供研究方向。     

PI3K/Akt/mTOR信号通路抑制剂在乳腺癌中的研究进展

目的:总结PI3K/Akt/mTOR信号通路靶向治疗在乳腺癌中的研究进展.方法:以“PI3K/Akt/mTOR、信号通路和乳腺癌”等为关键词,检索2000-01-2011-06 PubMed、Ovid和Springer等数据库的相关文献.纳入标准:1)关于PI3K/Akt/mTOR信号通路的组成、功能特点;2)PI3K/Akt/mTOR信号通路与乳腺癌的关系研究;3)以PI3K/Akt/mTOR信号通路中关键分子为靶点的乳腺癌治疗.根据纳入标准,符合分析的文献40篇.结果:信号转导通路的异常是肿瘤发生、发展的重要步骤,PI3K/Akt/mTOR信号通路与人类多种肿瘤密切相关,其在肿瘤细胞的增殖、存活、抵抗凋亡、血管发生和转移以及对放化疗抵抗中发挥了重要作用.乳腺癌中常见PI3K/Akt/mTOR信号通路的异常激活,以此通路为靶点的药物已成为乳腺癌治疗的研究热点.结论:靶向PI3K/Akt/mTOR通路中关键分子的众多药物在乳腺癌开展了一系列相关的临床试验研究,一部分显示出较好的安全性和有效性.随着对PI3K/Akt/mTOR通路的分子生物学机制的深入研究,期待靶向此通路的抑制剂将会在乳腺癌治疗中发挥巨大的作用,进一步提高乳腺癌患者的疗效和改善预后.     

曲妥珠单抗的耐药机制及其逆转策略

曲妥珠单抗(trastuzumab;商品名为Herceptin,赫赛汀)是靶向人表皮生长因子受体2(human epidermal growth factor receptor2,HER2)的人源化单克隆抗体,与化疗药物联用可显著提高患者的无进展生存期.然而,曲妥珠单抗的原发性和获得性耐药严重制约了其临床疗效及应用.PI3 K/AKT/mTOR信号通路的异常活化、HER家族成员间的相互作用、药物压力下代偿性生存信号的激活、肿瘤干细胞表型形成等均可能成为曲妥珠单抗耐药的重要机制.随着曲妥珠单抗耐药机制研究的不断深入,克服耐药的治疗手段也越来越丰富.有研究表明,曲妥珠单抗与其他靶向HER2胞外域的单克隆抗体或靶向其他HER家族成员的抗体类药物联用可增强曲妥珠单抗的疗效.应用PI3 K/AKT/mTOR信号通路的小分子抑制剂或耐药相关促生存信号通路的特异性抑制剂可有效逆转耐药发生,延长患者的疾病无进展生存期.深入研究曲妥珠单抗耐药的机制,不断探索逆转耐药的治疗策略,可为乳腺癌个性化治疗方案的建立提供依据.本文将对曲妥珠单抗耐药机制及克服耐药的研究进展做一介绍.     

曲妥珠单抗获得性耐药机制及应对策略

摘 要：曲妥珠单抗是靶向人表皮生长因子2(HER2)的单克隆抗体药物,对HER2表达阳性乳腺癌及胃癌治疗效果确切。然而多数患者在用药1年内出现了获得性耐药,导致其疗效降低甚至无效。研究表明,信号通路异常激活;表皮生长因子受体(EGFR)及其配体异常表达及肿瘤诱发上皮—间质转化(EMT)均可成为曲妥珠单抗耐药的重要机制,联合使用PI3K/AKT/mTOR通路抑制剂及其相关生存信号通路抑制剂可逆转曲妥珠单抗耐药。本文就曲妥珠单抗耐药机制及逆转耐药策略进行综述。     

靶向PI3K/AKT/mTOR信号通路治疗急性T淋巴细胞白血病的研究进展

急性T淋巴细胞白血病(T-ALL)是来源于胸腺T细胞祖细胞的具有强侵袭性和异质性的血液系统恶性肿瘤。T-ALL约占儿童急性淋巴细胞白血病(ALL)的15%,在成人ALL中的比例约为25%。强化化疗方案的应用使儿童T-ALL患者预后显著提高,但成人及复发耐药T-ALL患者的预后仍较差。研制新型靶向药物特异性阻断T-ALL细胞内生存及耐药相关的异常激活信号通路近年来被认为是治疗成人及复发难治T-ALL患者的新策略。PI3K/AKT/mTOR通路是T-ALL细胞内异常激活信号通路中具有代表性的一条。目前靶向该通路的多种小分子抑制剂已被成功研制,并在治疗T-ALL的研究中取得良好效果。PI3K/AKT/mTOR通路相关抑制剂较传统化疗药物具有更高的特异性和更低的毒副作用,且诸多研究表明其与低剂量化疗药物或其他靶向药物联合治疗T-ALL能发挥协同效应。本综述将总结近年来在PI3K/AKT/mTOR通路与T-ALL相关领域的研究成果,并对基于靶向该通路治疗T-ALL的研究进展一并阐述。     

PI3K/AKT/mTOR信号通路抑制剂治疗乳腺癌临床应用专家共识

磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(AKT)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路(PAM信号通路)在乳腺癌发生发展中发挥重要作用, 与晚期乳腺癌内分泌治疗耐药密切相关, 以PAM信号通路中的关键分子为靶点的抗癌治疗成为了近几年的研究热点。靶向PAM信号通路抑制剂为晚期乳腺癌患者尤其是激素受体阳性人表皮生长因子受体2阴性患者带来明显临床获益。目前, 美国食品和药物管理局批准上市的PAM信号通路抑制剂包括PI3K抑制剂Alpelisib和mTOR抑制剂依维莫司, 同时, 依维莫司也在国内获得批准用于乳腺癌新适应证, Alpelisib有望不久在中国上市。鉴于此, 专家制定了PAM信号通路抑制剂治疗晚期乳腺癌的临床应用专家共识, 系统地介绍了PAM信号通路的机制、PAM信号通路抑制剂的疗效、临床应用、不良事件管理及PIK3CA基因检测建议, 旨在提高中国临床肿瘤医师对PAM信号通路抑制剂的认知, 推进临床决策的精准性, 达到延长患者生存时间的目标。     

PI3K/AKT/mTOR通路及其抑制剂在乳腺癌中的应用现状

磷脂酰肌醇3-激酶（phosphoinositide 3-kinase,PI3K）/蛋白激酶B（protein kinase B,AKT）/哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）信号转导通路在多种肿瘤中异常激活,参与肿瘤细胞增殖、分化和凋亡等生命过程的调控,是抗肿瘤药物研发的重要靶点。对目前已应用于乳腺癌临床或处于临床试验阶段的PI3K/AKT/mTOR信号通路抑制剂进行归纳,并综述该通路抑制剂的联合用药策略,以期为不同亚型乳腺癌提供个体化靶向治疗方案。     

The PI3K/AKT/MTOR Signaling Pathway: The Role of PI3K and AKT Inhibitors in Breast Cancer

Breast cancer is the second leading cause of cancer death in women. Targeted therapies are available for HER2-positive and endocrine-sensitive disease while chemotherapy remains the mainstay of treatment for triple-negative breast cancer. The efficacy of all targeted interventions is, however, limited by primary or secondary resistance. Preclinical data show that active PI3K/AKT/mTOR signaling contributes to therapy resistance in HER2-positive and hormone-receptor-positive breast cancer. In line with these preclinical observations, clinical trials such as BOLERO-2 demonstrated a benefit of additional inhibition of mTOR signaling in advanced estrogen-receptor-positive breast cancer patients refractory to prior aromatase-inhibitor therapy. Besides the mTOR, several other proteins involved in the PI3K-pathway serve as potential therapeutic targets, such as PI3K and AKT. In this review, we summarize the current available knowledge and experimental and clinical research results about targeting the PI3K-pathway in breast cancer and, thus, provide the rationale for PI3K- and AKT-inhibitor use in the clinic.     

PI3K/AKT/mTOR通路抑制剂在膀胱癌中的研究进展

磷脂酰肌醇3-激酶(PI3K)/AKT/哺乳动物雷帕霉素靶标(mTOR)通路在人类肿瘤的恶性转化及其随后的生长、增殖和转移中起重要作用。临床前研究表明,PI3K/AKT/mTOR通路在膀胱癌中经常被激活。因此,这一通路被认为是膀胱癌治疗干预的候选通路,针对该通路不同成分的抑制剂正处于临床开发的不同阶段。在这里,重点介绍我们对PI3K/AKT/mTOR通路的最新研究进展,并讨论以该通路为靶点的治疗药物作为膀胱癌治疗药物的发展障碍及发展潜力。     

The PI3K/AKT/mTOR Signaling Pathway: Implications in the Treatment of Breast Cancer

Epidemiologic and experimental studies support a key role of the phosphatidyl inositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway in the biology of human cancers. Alterations resulting in activation of PI3K/Akt/mTOR signaling are perhaps the most frequent events observed in solid tumors, including breast cancer, and contribute to neoplastic transformation. The PI3K/mTOR pathway can be activated by overproduction of growth factors or chemokines, loss of phosphatase and tensin homolog (PTEN) expression, or by mutations in growth factor receptors Ras, PTEN, or PI3K itself. Activation of this pathway contributes to cell cycle proliferation, growth, cell cycle entry, survival, cell motility, protein synthesis, and glucose metabolism, all important aspects of tumorigenesis. The most common genetic aberrations in breast cancer are activating somatic missense mutations in the gene encoding the p110a (PIK3CA) subunit of PI3K. The PTEN gene is often hypermethylated or decreased in expression, through as yet unclear mechanisms, in breast cancer. Studies have shown that PI3K/PTEN/AKT pathway modulation is implicated in HER2/neu-tumorigenesis and in response to the HER2-targeting antibody trastuzumab. Components of the pathway are regulated by feed-back and cross-talk to other signaling cascades and appear to be implicated with drug resistance. Over the past few years, a number of components of this signaling cascade have been the subject of intense drug-discovery activities. Rapamycin analogs have already been shown to have antitumor efficacy in some tumor types. Newer-generation PI3K, AKT, and mTOR inhibitors have shown significant promise preclinically and are now in clinical trials. This article summarizes the progress made in the elucidation of the pathway, clinical implications in pathology of breast cancer, and reviews novel drugs targeting this pathway for cancer treatment, particularly inhibitors of PI3K, AKT, and mTOR, currently undergoing clinical trials. Potential combination strategies, safety concerns, and resistance mechanisms for this new generation of anticancer agents are also discussed.     

Overcoming acquired resistance to anticancer therapy: focus on the PI3K/AKT/mTOR pathway

Background

Most targeted anticancer therapies, as well as cytotoxic and radiation therapies, are encumbered by the development of secondary resistance by cancer cells. Resistance is a complex phenomenon involving multiple mechanisms, including activation of signaling pathways such as phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR). Novel strategies to overcome resistance by targeting these signaling pathways are being evaluated.

Methods

PubMed and key cancer congress abstracts were searched until July 2012 for preclinical and clinical data relating to the PI3K/AKT/mTOR pathway and anticancer treatment resistance, and use of PI3K/AKT/mTOR inhibitors in resistant cancer cell lines and patient populations.

Results

Activation of the PI3K/AKT/mTOR pathway is frequently implicated in resistance to anticancer therapies, including biologics, tyrosine kinase inhibitors, radiation, and cytotoxics. As such, inhibitors of the PI3K/AKT/mTOR pathway are being rapidly evaluated in preclinical models and in clinical studies to determine whether they can restore therapeutic sensitivity when given in combination. In breast cancer, non-small-cell lung cancer, and glioblastoma, we find compelling preclinical evidence to show that inhibitors of PI3K or mTOR can restore sensitivity in resistant cells. Although clinical evidence is less mature, a recent Phase III study with the mTORC1 inhibitor everolimus in patients with advanced breast cancer resistant to aromatase inhibition and several Phase I/II studies with PI3K inhibitors demonstrate proof-of-concept, warranting future clinical evaluation.

Conclusion

Current preclinical and clinical evidence suggest that inhibitors of the PI3K/AKT/mTOR pathway could have utility in combination with other anticancer therapies to circumvent resistance by cancer cells. Multiple clinical studies are ongoing.     

Inhibition of constitutively activated phosphoinositide 3‐kinase/AKT pathway enhances antitumor activity of chemotherapeutic agents in breast cancer susceptibility gene 1‐defective breast cancer cells

Loss or decrease of wild type BRCA1 function, by either mutation or reduced expression, has a role in hereditary and sporadic human breast and ovarian cancers. We report here that the PI3K/AKT pathway is constitutively active in BRCA1‐defective human breast cancer cells. Levels of phospho‐AKT are sustained even after serum starvation in breast cancer cells carrying deleterious BRCA1 mutations. Knockdown of BRCA1 in MCF7 cells increases the amount of phospho‐AKT and sensitizes cells to small molecule protein kinase inhibitors (PKIs) targeting the PI3K/AKT pathway. Restoration of wild type BRCA1 inhibits the activated PI3K/AKT pathway and de‐sensitizes cells to PKIs targeting this pathway in BRCA1 mutant breast cancer cells, regardless of PTEN mutations. In addition, clinical PI3K/mTOR inhibitors, PI‐103, and BEZ235, showed anti‐proliferative effects on BRCA1 mutant breast cancer cell lines and synergism in combination with chemotherapeutic drugs, cisplatin, doxorubicin, topotecan, and gemcitabine. BEZ235 synergizes with the anti‐proliferative effects of gemcitabine by enhancing caspase‐3/7 activity. Our results suggest that the PI3K/AKT pathway can be an important signaling pathway for the survival of BRCA1‐defective breast cancer cells and pharmacological inhibition of this pathway is a plausible treatment for a subset of breast cancers. © 2012 Wiley Periodicals, Inc.     

Overcoming acquired resistance to letrozole by targeting the PI3K/AKT/mTOR pathway in breast cancer cell clones

Development of resistance to endocrine therapy is a clinical issue in estrogen receptor (ER)-positive breast cancer. Here we show that persistent activation of AKT/mTOR signaling is crucial to the acquisition of letrozole resistance in cell clones generated from MCF-7/AROM-1 aromatase-expressing breast cancer cells after prolonged letrozole exposure. ERα plays a marginal role in this context. As a proof of concept, the association between PI3K/AKT/mTOR signaling and insensitivity to endocrine therapies was confirmed in breast cancer patients who developed early letrozole resistance in neoadjuvant setting. In addition our results suggest that, regardless of the mechanism mediating the activation of AKT/mTOR pathway, either RAD001 or NVP-BEZ235 treatment may represent a promising strategy to overcome acquired resistance to letrozole in breast cancers dependent on AKT/mTOR signaling.     

PI3K抑制剂在乳腺癌治疗中的应用现状

PI3K/Akt/mTOR信号通路是细胞内的重要信号通路,在调节肿瘤细胞的增殖、分化、转移过程中发挥重要作用.该信号通路的激活与多种肿瘤的发生和发展有密切关系.随着近些年对分子生物学的深入研究发现,磷脂酰肌醇3-激酶(PI3K)通路的异常激活在乳腺癌中最为常见,也使得该通路成为乳腺癌新的治疗靶点,现已研发出多种作用于P...     

mTOR抑制剂在乳腺癌内分泌治疗耐药中的研究进展

PI3K/Akt/mTOR信号转导通路可抑制肿瘤细胞凋亡、促进细胞生存、调节细胞周期,促进肿瘤新生血管的形成以及侵袭与转移,在肿瘤的发生、发展、治疗及转归中发挥着重要作用。该信号通路与乳腺癌关系非常密切,是乳腺癌新的治疗靶点及研究热点。mTOR抑制剂通过不同的靶点作用于PI3K/Akt/mTOR信号转导通路上,从而达到其抗癌作用。内分泌治疗是乳腺癌的重要治疗方式之一,与化疗等其他治疗方式一样,内分泌治疗同样也面临治疗耐受这一难题。随着越来越多的信号通路被揭示,单一阻断某一位点已经不能满足治疗的需要,寻找多条通路的共同抑制位点成为研究人员关注的焦点。本文就mTOR抑制剂在乳腺癌内分泌治疗耐药中的作用及其临床试验结果进行综述,以期进一步了解mTOR抑制剂的临床作用。