CAR-T细胞治疗实体瘤的现存挑战及优化策略

近年来,嵌合抗原受体T细胞（chimeric antigen receptor T-cell,CAR-T）疗法在血液肿瘤治疗中取得了突破性进展。然而,由于实体瘤异于血液肿瘤的特性,CAR-T在实体瘤治疗中并未取得很好的疗效。限制CAR-T疗效的关键因素主要包括实体瘤细胞本身及其特殊的肿瘤微环境（tumor microenvironment,TME）两方面,在CAR-T向肿瘤组织部位浸润、CAR-T在TME中维持抗肿瘤活性以及CAR-T对肿瘤细胞的靶向性识别杀伤等多个过程中损害CAR-T功能。为了解决这些问题,越来越多的临床前研究提出了潜在有效的解决办法,相应的临床研究也相继开展。本文将对CAR-T细胞治疗实体瘤的现存挑战及相应的优化策略进行综述,以期为CAR-T疗法的未来探索提供参考。      

用于实体瘤治疗的缺氧敏感型CAR-T细胞的研究进展

嵌合抗原受体T(chimeric antigen receptor T,CAR-T)细胞治疗作为一种肿瘤免疫疗法已经在血液系统肿瘤的临床治疗中取得良好效果。然而,由于实体瘤缺乏肿瘤特异性抗原,大多数CAR-T细胞以同样在机体其他正常组织器官中广泛表达的肿瘤相关抗原作为识别靶点,导致脱靶效应的产生,严重时甚至会危及患者生命。由于脱靶效应的存在,CAR-T细胞治疗在实体瘤治疗领域中的应用受到严重限制。为克服CAR-T细胞治疗中脱靶效应的影响,可以利用肿瘤微环境中氧含量低的特点,设计缺氧敏感型CAR-T细胞,使其仅在乏氧的肿瘤微环境中表达靶向肿瘤相关抗原的CAR,从而避免CAR-T细胞对正常组织器官的“误伤”。本文综述缺氧敏感型CAR-T细胞构建的常用元件和思路,梳理近年来构建缺氧敏感型CAR-T细胞的研究进展,有望加强CAR-T细胞治疗的安全性,提高CAR-T细胞在实体瘤治疗中的效果。     

CAR-T细胞治疗突破实体肿瘤微环境新策略的研究进展

免疫治疗可通过提高患者自身免疫力以达到抗肿瘤目的,其中嵌合型抗原受体修饰T细胞(chimeric antigen receptor modified T cells,CAR-T)在血液系统肿瘤中已显现出良好疗效。实体肿瘤微环境(tumor microenvironment,TME)中免疫抑制细胞及分子等可限制CAR-T细胞在肿瘤部位浸润及其在浸润部位产生细胞毒作用。因此CAR-T细胞治疗在血液系统肿瘤中的显著疗效未在实体肿瘤中呈现。本文就如何突破TME限制,提高CAR-T细胞归巢能力及细胞毒作用,从而提高其在实体瘤中的疗效做一综述。     

CAR-T细胞治疗实体瘤的归巢障碍及解决方法

嵌合抗原受体T(chimeric antigen receptor T,CAR-T)细胞治疗为一种新兴的免疫治疗,已在血液肿瘤治疗方面取得较大突破。但在实体瘤治疗方面却进展甚微,可能与CAR-T细胞在治疗实体瘤过程中难以有效归巢到肿瘤组织有关。实体瘤中复杂的肿瘤微环境以及肿瘤组织的屏障作用使CAR-T细胞无法和肿瘤细胞直接接触,从而无法发挥其抗肿瘤活性。本文就CAR-T细胞在治疗实体瘤中的归巢障碍及克服归巢障碍的方法进行综述。      

CAR-T细胞治疗实体肿瘤的新策略

[摘要] 嵌合型抗原受体修饰T(chimeric antigen receptor modified T,CAR-T)细胞治疗作为一种新的过继性免疫疗法在血液肿瘤中已取得了较好的疗效。在实体肿瘤中,肿瘤微环境中存在大量免疫抑制细胞、免疫抑制分子以及胞外基质,对迁移的CAR-T细胞的细胞毒性效应产生抑制作用,在实体肿瘤内严重抑制CAR-T细胞的抗肿瘤效力。同时,大多数实体肿瘤存在肿瘤异质性且缺乏相对特异性肿瘤抗原,CAR-T细胞在实体肿瘤部位的归巢能力差并伴随着脱靶效应,使其在实体瘤中的疗效欠佳。与血液肿瘤相比,实体瘤具有复杂的生物学特性,需要针对性的策略才能保证CAR-T细胞抗肿瘤长期有效。本文就CAR-T 细胞的发展、在实体瘤治疗中的困惑及治疗策略的研究进展作一阐述。     

Challenges and prospects of chimeric antigen receptor T cell therapy in solid tumors

Chimeric antigen receptor (CAR) T cell therapy is a novel and innovative immunotherapy. CAR-T cells are genetically engineered T cells, carrying MHC independent specific antigen receptor and co-stimulatory molecule which can activate an immune response to a cancer specific antigen. This therapy showed great results in hematological malignancies but were unable to prove their worth in solid tumors. Likely reasons for their failure are lack of antigens, poor trafficking, and hostile tumor microenvironment. Excessive amount of research is going on to improve the efficacy of CAR T cell therapy in solid tumors. In this article, we will discuss the challenges faced in improving the outcome of CAR T cell therapy in solid tumors and various strategies adopted to curb them.     

CAR-T在胃癌免疫治疗中的研究进展

胃癌是最常见的恶性肿瘤之一,部分病例由于诊断较晚和治疗不佳,患者的整体生存期较差。近几年,嵌合抗原受体修饰T细胞（chimeric antigen receptor T cells,CAR-T）疗法在肿瘤治疗研究领域受到相当大的关注,且已在血液系统肿瘤中发挥了重要作用,但在实体肿瘤因受到靶点特异性,肿瘤微环境等因素影响而作用受限。尽管如此,各种临床前和临床实验已证实CAR-T细胞免疫治疗是胃癌一种有前景的治疗方法,并具有有别于其他实体瘤的优势,但是仍面临诸多挑战。本文将系统介绍CAR-T疗法在胃癌中的最新研究进展。      

血液肿瘤CAR-T细胞治疗的现状与挑战

过继性细胞免疫疗法（adoptive cellular immunotherapy,ACI）是药物开发中一种全新模式,目前已具备在肿瘤疾病中带来临床益处的明确证据。其中嵌合抗原受体修饰的T细胞（chimeric antigen receptor-modified T cells,CAR-T）疗法利用基因工程技术重编程T细胞,使其具备非主要组织相容性抗原复合物（major histocompability complex,MHC）限制性的靶向结合并杀伤肿瘤细胞的能力,并在急性B淋巴细胞性白血病（B-cell acute lymphoblastic leukemia,B-ALL）、非霍奇金淋巴瘤（non-Hodgkin's lymphoma,NHL）、多发性骨髓瘤（multiple myeloma,MM）患者中展现出显著的缓解率,为难治复发性血液肿瘤疾病提供了治愈希望,因此多项商品化CAR-T产品也获批应用于临床,开拓了肿瘤免疫治疗的新时代。然而,细胞因子释放综合征（cytokine release syndrome,CRS）、免疫效应细胞相关神经毒性综合征（immune effector cell-associated neurotoxicity syndrome,ICANS）和其他并发症的发生是其应用的安全性挑战,并且部分患者发生CAR-T治疗无效或复发,需要提出优化CAR-T细胞疗法的新策略,在不同水平强化肿瘤清除作用,以确保安全性和有效性。本文对血液肿瘤领域的CAR-T细胞疗法临床研究进展进行综述,并归纳了下一代CAR-T细胞疗法面临的主要挑战,为拓展CAR-T细胞基础研究及临床转化研究方向提供思路。      

树突状细胞临床治疗实体瘤：峰回路转

肿瘤免疫细胞疗法展现了良好的临床抗肿瘤前景。树突状细胞（DC）识别肿瘤抗原作为机体免疫响应的关键起始步骤,捕获肿瘤抗原后分化成熟,在淋巴结将抗原信号提呈给CD4+ T细胞、CD8+ T细胞等免疫细胞,激发抗肿瘤效应,应用于肿瘤治疗,尤其是实体瘤,被寄予厚望。但由于实体瘤TME复杂的结构特点、DC和T/B 细胞免疫响应的机制不清晰等问题犹如崇山峻岭摆在眼前,故未能形成关键理论和技术突破。以CAR-T 细胞为代表的精准细胞免疫疗法已表现出优势,但仍面临抗原选择瓶颈。DC治疗性疫苗在临床试验中表现出良好的疗效和安全性,随着DC在TME中关键作用机制的进一步揭示,研究者的目光重新聚焦在DC抗肿瘤效应,推动着DC与其他手段的联合疗法、工程化DC疫苗等实体瘤治疗方案从基础向临床转化,目前正迈入DC临床治疗实体瘤的新阶段。本文系统地对DC治疗实体瘤的临床研究进展、实体瘤TME中DC的种类及其抗肿瘤机制、工程化DC疫苗,以及面临的挑战和应对策略等问题进行了评述。     

Anti-tumor efficacy of human anti-c-met CAR-T cells against papillary renal cell carcinoma in an orthotopic model

Chimeric antigen receptor (CAR)-T cell therapy has shown salient efficacy in cancer immunotherapy, particularly in the treatment of B cell malignancies. However, the efficacy of CAR-T for solid tumors remains inadequate. In this study, we displayed that c-met is an appropriate therapeutic target for papillary renal cell carcinoma (PRCC) using clinical samples, developed an anti-human c-met CAR-T cells, and investigated the anti-tumor efficacy of the CAR-T cells using an orthotopic mouse model as pre-clinical research. Administration of the anti-c-met CAR-T cells induced marked infiltration of the CAR-T cells into the tumor tissue and unambiguous suppression of tumor growth. Furthermore, in combination with axitinib, the anti-tumor efficacy of the CAR-T cells was synergistically augmented. Taken together, our current study demonstrated the potential for clinical application of anti-c-met CAR-T cells in the treatment of patients with PRCC.     

Cellular based treatment modalities for unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and is unfortunately associated with an overall poor prognosis and high mortality. Early and intermediate stages of HCC allow for treatment with surgical resection, ablation and even liver transplantation, however disease progression warrants conventional systemic therapy. For years treatment options were limited to molecular-targeting medications, of which sorafenib remains the standard of care. The recent development and success of immune checkpoint inhibitors has proven to be a breakthrough in the treatment of HCC, but there is an urgent need for the development of further novel therapeutic treatments that prolong overall survival and minimize recurrence. Current investigation is focused on adoptive cell therapy including chimeric antigen receptor-T cells (CAR-T cells), T cell receptor (TCR) engineered T cells, dendritic cells, natural killer cells, and tumor infiltrating lymphocyte cells, which have shown remarkable success in the treatment of hematological and solid tumor malignancies. In this review we briefly introduce readers to the currently approved systemic treatment options and present clinical and experimental evidence of HCC immunotherapeutic treatments that will hopefully one day allow for revolutionary change in the treatment modalities used for unresectable HCC. We also provide an up-to-date compilation of ongoing clinical trials investigating CAR-T cells, TCR engineered T cells, cancer vaccines and oncolytic viruses, while discussing strategies that can help overcome commonly faced challenges when utilizing cellular based treatments.     

CAR-T疗法在卵巢癌中的应用前景

卵巢癌是最致命的妇科肿瘤,由于其发病潜伏期长,缺乏早期诊断手段,导致大多数患者初治时已是晚期。除了常规的手术化疗外,近年来,嵌合抗原受体修饰的T细胞(CAR-T)在肿瘤系统治疗的研究领域中受到相当大的关注。各种临床前实验和临床试验已证实了CAR-T细胞免疫疗法是卵巢癌的一种有前景的治疗方法,并显示出有别于其他实体瘤的优势,但是仍需要面对诸多挑战。在这篇综述中,我们将系统的讲述CAR-T细胞免疫疗法的最新研究进展,包括CAR-T细胞疗法的生物学理解、临床应用、所面对的挑战及可能改善治疗效果的策略。     

CAR-NK在实体瘤治疗中的研究进展

瘤免疫细胞治疗近年来备受瞩目。嵌合抗原受体T(chimeric antigen receptor engineered T-cell,CAR-T)细胞用于治疗血液系统恶性肿瘤已经颇见成效,但在实体瘤治疗方面却存在不足。由于具有不同于T细胞的非特异性杀伤肿瘤细胞的能力,CAR修饰的自然杀伤(nature killer,NK)细胞逐渐成为研究热点。目前,广泛的临床前研究证明了CAR-NK细胞疗法的安全性和有效性,尤其在实体瘤治疗方面,展现出了优于CAR-T细胞的应用前景。然而,CAR-NK细胞疗法仍存在一些局限性,需要进一步研究以期实现其临床转化。     

多靶点CAR-T细胞治疗肿瘤的研究进展

嵌合抗原受体T细胞（CAR-T）是一种过继细胞免疫疗法,其通过基因手段改造T细胞,从而发挥肿瘤靶向杀伤作用。CAR-T细胞疗法在治疗肿瘤,特别是血液系统恶性肿瘤方面具有显著的作用,但在实体肿瘤中作用不佳。单靶点的CAR-T在应用的过程中容易出现脱靶效应,存在复发或更加难治的风险。双靶点或多靶点CAR-T的开发有望扩大靶细胞抗原覆盖率,有效避免抗原逃逸和防止肿瘤复发,延长患者的生存时间。本文综述了目前多靶点嵌合抗原受体T细胞的研究进展,并探讨了其发展的前景。     

过继性T细胞治疗在非小细胞肺癌中的研究进展

T细胞是获得性抗肿瘤免疫的重要细胞亚群,但肿瘤组织中的T细胞数量少,且处于免疫抑制甚至耗竭状态,这是导致肿瘤免疫逃逸和免疫检查点抑制剂等抗肿瘤免疫治疗效果不佳的重要原因。过继性T细胞治疗主要包括肿瘤浸润淋巴细胞（tumor-infiltrating lymphocytes,TILs）、嵌合抗原受体T细胞（chimeric antigen receptor T-cell,CAR-T）、T细胞受体工程化T细胞（T-cell receptor engineering T cell,TCR-T）治疗,其通过体外筛选扩增富集肿瘤特异性T细胞或通过基因改造赋予T细胞新的抗原特异性（CAR-T、TCR-T）,有效克服了肿瘤浸润T细胞不足的缺陷。虽然过继性T细胞治疗在非小细胞肺癌（non-small cell lung cancer,NSCLC）中的研究起步较晚,但已显示治疗的安全可行性和初步抗肿瘤效果,值得进一步深入研究。本文将对TILs、CAR-T、TCR-T的原理、培养方法、生物学特征以及在NSCLC治疗中的研究进展进行综述,以期为优化临床研究设计和开展新型NSCLC免疫治疗提供新思路。      

CAR-T细胞治疗的神经毒性副反应处理新策略

[摘要] 嵌合型抗原受体修饰T (chimeric antigen receptor modified T,CAR-T)细胞疗法是肿瘤免疫治疗的重要手段之一,CAR-T细胞的靶向性、杀伤活性、增殖性和持久性较常规T细胞明显提高,并且经过不断的改进演变,其在血液系统肿瘤治疗中取得了巨大的成效,受到广泛的关注。然而,其治疗过程中出现的神经毒性,也称CAR-T细胞相关脑病综合征(CAR-T cell relevant encephalopathy syndrome,CRES),影响了CAR-T疗法的临床应用。探索CRES的发病机制及其高风险因素、寻找相应的处理策略,对预防和治疗CRES具有重要意义。本文以CD19-CAR-T 细胞治疗为例,就CRES的发病症状、发病机制、高风险因素及应对策略作一综述,为临床治疗提供参考。     

Chimeric antigen receptor-T cell therapy for solid tumors require new clinical regimens

Introduction: Chimeric antigen receptor modified T cell (CAR-T) therapy has achieved encouraging breakthroughs in the treatment of hematological malignancies. Nevertheless, this success has not yet been extrapolated to solid tumors. This review focuses on new clinical regimens that could improve the therapeutic efficacy of CAR-T in solid tumors.

Areas covered: Herein, the authors reviewed recent clinical trials using CAR-T therapies for the treatment of solid tumors. Specifically, this review covered the following areas: (1) the current status of CAR-T cells in the treatment of solid tumors; (2) the major factors constraining the efficacy of CAR-T cells in solid tumors; and (3) opinions regarding the future of CAR-T as a treatment for solid tumors.

Expert commentary: While some recent studies have shown promising results, the ultimate success of CAR-T therapies in solid tumor patients will require the following improvements to clinical regimens: (1) local delivery of CAR-T cells; (2) combination of CAR-T cells with chemotherapeutic drugs to treat metastatic tumors; (3) combination of CAR-T with immune checkpoint inhibitors; (4) combination therapy using CAR-T cells targeting two different antigens; and (5) the use of CAR-T as a strategy to prevent tumor recurrence and metastasis after radical resection.     

CAR-T细胞治疗实体肿瘤：且行且思考

[摘要] 由于T细胞免疫具有长效性、可放大性、多靶点性等特点,以T细胞为核心的肿瘤免疫治疗被认为是除手术外最有可能带来肿瘤治愈的治疗手段。尤其近年来不断累积的临床数据证实了以嵌合抗原受体修饰T(chimeric antigen receptor modified T, CAR-T）细胞为代表的细胞治疗的安全性与有效性,其中以CD19 为靶点的CAR-T细胞疗法由于效果显著,已成为多数临床研究机构开展基因修饰T细胞治疗研究的模式疗法。但是,实践和理论均显示,CAR-T细胞在实体肿瘤的治疗中面临着更严峻的挑战,如何更加合理有效的开展CAR-T细胞治疗实体肿瘤仍需要不断地探索。本文回顾了CAR-T细胞治疗临床实践历程、治疗实体瘤的现状,阐述了需要解决的问题及未来的发展方向,旨在为CAR-T细胞治疗实体肿瘤提供借鉴及研究思路。     

Fueling chimeric antigen receptor T cells with cytokines

Chimeric antigen receptor (CAR)-T therapy started a new era of tumor treatment, especially for hematological malignancies. However, many challenges remain, including low-level proliferation and short-term persistence, insufficient CAR T-cell trafficking, suppressive tumor microenvironment (TME), frequent adverse events and the unaffordable manufacturing process. Cytokines are pleiotropic hormones involved in multiple processes of immunity, including activation, expansion, differentiation, and migration of immune cells. Both pre-clinical models and clinical trials showed that armoring CAR-T cells with cytokines strengthened the anti-tumor responses of CAR T cells. This review looked into the key role of cytokines as a promoter of anti-tumor activities of CAR-T cells and consequently a facilitator of clinical translation, mainly, from cytokines of the common γ-chains family, chemokines and chemokine receptors, immunosuppressive molecules and pro-inflammatory cytokines.     

个体化肿瘤特异TCR的筛选策略

基因修饰T细胞疗法在肿瘤治疗领域取得突破性进展，主要包括嵌合抗原受体基因修饰T（chimeric antigen receptor engineered T，CAR-T）细胞和T细胞受体基因修饰T（T-cell receptor modified T，TCR-T）细胞。虽然CAR-T细胞疗法在血液系统 肿瘤治疗领域呈现良好的临床治疗效果，但CAR-T细胞仅能识别肿瘤细胞膜抗原（占细胞全部抗原的比例约10%），而TCR-T细 胞可以识别人白细胞抗原（human leukocyte antigen，HLA）提呈的细胞内抗原，因此TCR-T细胞可以识别更多种类的肿瘤抗原，进 而实现对CAR-T细胞的合理补充。由于TCR-T细胞需要同时识别细胞内抗原和对应的HLA，而不同患者的HLA分型和表达的 肿瘤抗原都可能存在巨大差异，因此有必要为每个/每类肿瘤患者定制个体化的TCR-T细胞，其中的关键为筛选特异识别肿瘤抗 原的TCR。当前主要有筛选靶向“已知”肿瘤抗原TCR和筛选靶向“未知”肿瘤抗原TCR的两种策略，但其各有适用性，应针对每 个患者制定适合的筛选方法，以制备多种肿瘤特异性TCR-T细胞，从而实现个体化TCR-T细胞的肿瘤治疗。