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。     

PI3K/AKT/mTOR信号通路抑制剂治疗结直肠癌的研究进展

PI3K/AKT/mTOR通路的异常活化在结直肠癌的发生发展中起到重要作用,以此通路为靶点的药物已成为结直肠癌治疗的研究热点,临床前和临床试验研究证明,针对PI3K/AKT/mTOR通路的多种抑制剂具有抗肿瘤活性。越来越多的临床数据显示,PTEN缺乏或PIK3CA基因突变对PI3K/AKT/mTOR通路抑制剂敏感,KRAS突变则预示着耐药;寻找针对这一通路抑制剂敏感的优势人群也成为结直肠癌的研究热点;此外,PI3K/AKT/mTOR通路也会影响常规治疗的疗效,因此PI3K/AKT/mTOR通路抑制剂联合细胞毒治疗方案在结直肠癌中可能起到协同作用。     

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.     

PI3K/AKT/mTOR通路调控乳腺癌细胞FASN过表达的分子机制

目的:研究PI3K/AKT/mTOR通路在乳腺癌细胞FASN过表达中的作用,研究抑制该通路能否协同FASN抑制剂发挥靶向抗肿瘤作用。方法:荧光素酶检测法检测mTOR抑制剂rapamycin对乳腺癌细胞FASN转录活性的影响。Western blotting检测PI3K抑制剂LY294002及rapamycin对乳腺癌细胞AKT、pAKT、mTOR通路成员以及FASN的表达影响。分别给予乳腺癌细胞FASN抑制剂cerulenin、rapamycin及两者联合给药,MTT法检测不同干预法对细胞存活的影响。结果:Rapamycin可明显降低乳腺癌细胞FASN启动子活性,其中在FASN过表达的SKBR3细胞中最明显。LY294002作用后pAKT、pmTOR、FASN的表达均明显降低。Ra-pamycin作用后mTOR、pmTOR、p4EBP-1、pp70S6K及FASN的表达均明显下调。Cerulenin可对乳腺癌细胞产生细胞毒作用,在SKBR3中更显著。Rapamycin对乳腺癌细胞的细胞毒作用与FASN的表达无关。Rapam-ycin能够协同cerulenin对乳腺癌细胞产生细胞毒作用,且在SKBR3细胞中更明显,小剂量rapamycin联合小剂量cerulenin即达到较大细胞毒作用。结论:PI3K/AKT/mTOR通路参与调控乳腺癌细胞FASN的过表达,mTOR通路抑制剂联合FASN抑制剂有望成为高侵袭性乳腺癌新的治疗方法。     

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.     

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。     

内质网激动剂调控PI3K/AKT/mTOR通路诱导人小细胞肺癌NCI-H446细胞凋亡

目的 检测内质网应激能否通过PI3K/AKT/mTOR通路对人小细胞肺癌NCI-H446细胞凋亡产生作用.方法 采用MTT法检测不同浓度衣霉素对人小细胞肺癌NCI-H446的细胞毒性,Annexin V/PI检测药物作用下人小细胞肺癌NCI-H446细胞凋亡情况,Western Blot检测PI3K/AKT/mTOR通路相关蛋白的表达.结果 衣霉素可抑制人小细胞肺癌NCI-H446细胞的活性,且呈时间和浓度依赖性.衣霉素能够激活内质网应激,抑制PI3K/AKT/mTOR信号通路,使PI3K、AKT、mTOR蛋白磷酸化下调,诱导细胞凋亡.结论 内质网激动剂能够调控PI3K/AKT/mTOR通路诱导人小细胞肺癌NCI-H446细胞凋亡.     

PI3K/AKT/mTOR信号通路在三阴性乳腺癌中的作用及靶向治疗研究进展

摘 要：三阴性乳腺癌（triple negative breast cancer，TNBC）是一种特殊类型的乳腺癌亚型，占所有乳腺癌的15%，具有高度异质性。目前临床上以化疗为主要治疗手段，但效果并不理想。全文主要介绍了TNBC的生物学特点、分子分型和重要相关通路，其中PI3K/AKT/mTOR 信号传导通路在TNBC中尤为重要，该通路上的相关靶点为TNBC提供了更好的精准治疗。     

顺铂通过抑制PI3K/AKT/mTOR信号通路诱导子宫内膜癌Ishikawa细胞自噬

目的：探讨顺铂对子宫内膜癌Ishikawa细胞自噬的影响,并初步探讨PI3K/AKT/mTOR信号通路在其中的作用。方法：透射电镜观察自噬泡形成,免疫荧光检测微管相关蛋白1轻链3融合蛋白II（microtubule-associated protein 1 light chain 3II,LC3II） 的荧光聚集情况。采用Westerblot检测mTOR通路中的PI3K、AKT及mTOR蛋白的表达。结果：顺铂（20μg/mL）能诱导Ishikawa细胞发生自噬,其中24h组明显高于12h组（P<0.05）;与对照组（20μg/mL-0h组）相比较,自噬相关蛋白-LC3的表达随着时间延长表达增加（P<0.05）。磷酸化AKT1、磷酸化mTOR及PI3Kp85蛋白表达水平随着时间延长表达下降。胰岛素样生长因子-1（insulin-like growth factors-1,IGF-1）与顺铂共培养组自噬小体及LC3蛋白表达少于顺铂组,但高于对照组。结论：顺铂可能通过抑制PI3K/AKT/mTOR信号通路,从而诱导子宫内膜癌细胞发生自噬。     

PI3K/AKT/mTOR信号通路抑制剂在淋巴瘤中的研究进展*

磷脂酰肌醇-3 激酶（phosphatidylinositol 3-kinase,PI 3K）- 蛋白激酶B（protein kinaseB ,PKB ,又称AKT ）- 雷帕霉素靶蛋白（mammalian target of? rapamycin,mTOR）信号通路与细胞的生长、增殖、分化、凋亡、代谢等密切相关,在多种实体肿瘤中已发现该信号通路的异常。近年来,以抑制该通路特定位点的靶向治疗已成为抗肿瘤的研究热点。许多该位点新型抑制剂也已进入淋巴瘤的临床试验中,本文就该通路在淋巴瘤中的活化状态及各个分子靶点抑制剂的研究进展做一综述。      

Targeting the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway: An emerging treatment strategy for squamous cell lung carcinoma

Squamous cell lung carcinoma accounts for approximately 30% of all non-small cell lung cancers (NSCLCs). Despite progress in the understanding of the biology of cancer, cytotoxic chemotherapy remains the standard of care for patients with squamous cell lung carcinoma, but the prognosis is generally poor. The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway is one of the most commonly activated signaling pathways in cancer, leading to cell proliferation, survival, and differentiation. It has therefore become a major focus of clinical research. Various alterations in the PI3K/AKT/mTOR pathway have been identified in squamous cell lung carcinoma and a number of agents targeting these alterations are in clinical development for use as single agents and in combination with other targeted and conventional treatments. These include pan-PI3K inhibitors, isoform-specific PI3K inhibitors, AKT inhibitors, mTOR inhibitors, and dual PI3K/mTOR inhibitors. These agents have demonstrated antitumor activity in preclinical models of NSCLC and preliminary clinical evidence is also available for some agents. This review will discuss the role of the PI3K/AKT/mTOR pathway in cancer and how the discovery of genetic alterations in this pathway in patients with squamous cell lung carcinoma can inform the development of targeted therapies for this disease. An overview of ongoing clinical trials investigating PI3K/AKT/mTOR pathway inhibitors in squamous cell lung carcinoma will also be included.     

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。     

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.     

The phosphatidylinositol 3-kinase/Akt/mTOR signaling network as a therapeutic target in acute myelogenous leukemia patients

The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling axis plays a central role in cell proliferation, growth, and survival under physiological conditions. However, aberrant PI3K/Akt/mTOR signaling has been implicated in many human cancers, including acute myelogenous leukemia (AML). Therefore, the PI3K/Akt/mTOR network is considered as a validated target for innovative cancer therapy. The limit of acceptable toxicity for standard polychemotherapy has been reached in AML. Novel therapeutic strategies are therefore needed. This review highlights how the PI3K/Akt/mTOR signaling axis is constitutively active in AML patients, where it affects survival, proliferation, and drug-resistance of leukemic cells including leukemic stem cells. Effective targeting of this pathway with small molecule kinase inhibitors, employed alone or in combination with other drugs, could result in the suppression of leukemic cell growth. Furthermore, targeting the PI3K/Akt/mTOR signaling network with small pharmacological inhibitors, employed either alone or in combinations with other drugs, may result in less toxic and more efficacious treatment of AML patients. Efforts to exploit pharmacological inhibitors of the PI3K/Akt/mTOR cascade which show efficacy and safety in the clinical setting are now underway.     

Targeting the PI3K/AKT/mTOR pathway in biliary tract cancers: A review of current evidences and future perspectives

Biliary tract cancers (BTCs) are a group of invasive neoplasms, with increasing incidence and dismal prognosis. In advanced disease, the standard of care is represented by first-line chemotherapy with cisplatin and gemcitabine. In subsequent lines, no clear recommendations are currently available, highlighting the need for novel therapeutic approaches.The PI3K/AKT/mTOR pathway is a core regulator of cell metabolism, growth and survival, and is involved in BTCs carcinogenesis and progression. Mutations, gene copy number alterations and aberrant protein phosphorylation of PI3K, AKT, mTOR and PTEN have been thoroughly described in BTCs and correlate with poor survival outcomes.Several pre-clinical evidences state the efficacy of PI3K/AKT/mTOR pathway inhibitors in BTCs, both in vitro and in vivo. In the clinical setting, initial studies with rapamycin analogs have shown interesting activity with an acceptable toxicity profile. Novel strategies evaluating AKT and PI3K inhibitors have risen serious safety concerns, pointing out the need for improved patient selection and increased target specificity for the clinical development of these agents, both alone and in combination with chemotherapy.This review extensively describes the role of the PI3K/AKT/mTOR pathway in BTCs and examines the rationale of its targeting in these tumors, with particular focus on clinical activity, toxicities and perspectives on further development of PI3K/AKT/mTOR pathway inhibitors.     

Will PI3K pathway inhibitors be effective as single agents in patients with cancer?

The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) axis regulates essential cellular functions including cell survival, proliferation, metabolism, migration, and angiogenesis. The PI3K pathway is activated in human cancers by mutation, amplification, and deletion of genes encoding components of this pathway. The critical role of PI3K in cancer has led to the development of drugs targeting the effector mechanisms of this signaling network. Recent studies have shown that inhibition at multiple levels of the PI3K pathway results in FOXO-dependent feedback reactivation of several receptor tyrosine kinases (RTKs) which, in turn, limit the sustained inhibition of this pathway and attenuates the action of therapeutic antagonists. This suggests that if used as single agents, PI3K pathway inhibitors may have limited clinical activity. We propose herein that to successfully target the output of the PI3K pathway in cancer cells, combination therapies that hinder these compensatory mechanisms should be used. Thus, combination therapies that target RTKs, PI3K, and mTOR activities may be required to maximize the clinical benefit derived from treatment with these inhibitors.     

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.