肿瘤微环境中的细胞调控网络及促瘤机制

肿瘤微环境是指肿瘤发生发展的复杂组织环境,在肿瘤的生长、侵袭和转移过程中发挥重要作用。深入探究肿瘤微环境的组成和促瘤机制对发掘新的肿瘤治疗靶点具有重要意义。现以肿瘤微环境中的免疫细胞、间充质细胞和内皮细胞为切入点,概述它们与肿瘤细胞之间的相互作用,探讨肿瘤微环境通过抑制免疫细胞、调控间充质细胞和诱导血管生成来促进肿瘤的发生、发展和转移的调控机制,最后对靶向肿瘤微环境的免疫疗法进行了展望。     

免疫细胞与肿瘤微环境（英文）

肿瘤细胞和免疫细胞间的相互作用一直是肿瘤生物学关注的热点.流行病学与临床研究均表明,炎症反应与肿瘤的发生发展存在密切关联,但是其中的分子作用机理和遗传学机制尚未完全阐明.研究显示,T淋巴细胞、巨噬细胞、树突状细胞、巨大细胞等多种免疫细胞会浸润到肿瘤微环境中,协同调控肿瘤生长、免疫逃逸和侵袭转移.本文就近年对肿瘤微环境中免疫细胞功能研究的进展进行综述.正确认识这些免疫细胞在肿瘤发生发展中的作用,对于发展更优的肿瘤免疫治疗手段具有十分重要意义.     

调节性T细胞与胶质瘤的免疫治疗

调节性T细胞（regulatory T cell,Treg）是一群具有抑制其它免疫细胞功能的起负性调控的细胞群. Treg细胞能抑制多种免疫细胞,如CD4+T和CD8+T淋巴细胞、NK细胞、B淋巴细胞以及树突状细胞的活化和增殖,是体内维持免疫系统稳定,防止出现自身免疫性疾病重要因素.最新研究表明,Treg细胞在肿瘤免疫逃逸中也发挥重要作用. 肿瘤细胞通过扩增或招募Treg细胞,抑制机体对肿瘤的免疫作用,由此可知,Treg细胞在肿瘤的发生和发展过程中发挥重要作用. 因此,抑制Treg细胞的活性和数量是包括胶质瘤在内的肿瘤免疫治疗有效的方式.     

肿瘤微环境中相关细胞的研究进展

肿瘤的微环境对肿瘤的发生,发展具有重要的意义。实体瘤中除肿瘤细胞外存在大量的非肿瘤细胞,如肿瘤闻质细胞、成纤维细胞、血管内皮细胞、免疫细胞、脂肪细胞等等,这一系列的细胞与肿瘤细胞相互作用,通过一系列的因子分泌而促使肿瘤的进一步的恶化,目前传统的抗肿瘤药物研究往往局限于肿瘤细胞本身而忽略了肿瘤周围的细胞作用,使得肿瘤久治不愈。将来的药物开发应该围绕肿瘤细胞为主体的同时,兼顾微环境中的其他细胞,多靶点治疗肿瘤,真正实现肿瘤的治愈。     

γδT细胞在肿瘤免疫治疗中的研究进展

癌症是威胁人类健康最主要的疾病之一,目前临床上主要采用的手术/放化疗联合治疗的疗效有限,因此如何进一步提高肿瘤临床疗效仍是巨大的挑战。免疫细胞过继是肿瘤治疗技术中迅速发展的一种生物治疗技术,通过输入自身或同种"抗肿瘤免疫效应细胞"达到直接杀伤肿瘤或增强机体自身细胞免疫功能的作用。由于γδT细胞对肿瘤细胞具有强有力的直接细胞毒性,并可与其他免疫细胞协同作用发挥其抗肿瘤活性,因而成为了细胞免疫治疗中新的研究热点。本文主要叙述了γδT细胞与肿瘤相关的基础研究及临床试验的最新进展。     

肿瘤微环境中相关细胞的研究进展

肿瘤的微环境对肿瘤的发生,发展具有重要的意义。实体瘤中除肿瘤细胞外存在大量的非肿瘤细胞,如肿瘤间质细胞、成纤维细胞、血管内皮细胞、免疫细胞、脂肪细胞等等,这一系列的细胞与肿瘤细胞相互作用,通过一系列的因子分泌而促使肿瘤的进一步的恶化,目前传统的抗肿瘤药物研究往往局限于肿瘤细胞本身而忽略了肿瘤周围的细胞作用,使得肿瘤久治不愈。将来的药物开发应该围绕肿瘤细胞为主体的同时,兼顾微环境中的其他细胞,多靶点治疗肿瘤,真正实现肿瘤的治愈。     

细胞微环境对免疫细胞黏附与迁移的调控

免疫细胞的黏附与迁移是机体免疫与宿主防御的关键环节,在机体免疫监视以及稳态维持中发挥重要作用,甚至参与到癌细胞转移的过程中。免疫细胞在血管内皮表面的滚动、活化、稳定黏附和定向迁移依赖整合素功能,并受到细胞微环境,包括生物微环境、化学微环境以及物理微环境的多因子协同作用和调控。细胞微环境的紊乱往往导致免疫细胞黏附与迁移的异常,引发炎症性疾病,甚至肿瘤。将对细胞微环境通过整合素调控免疫细胞黏附与迁移进行概述,重点介绍生物微环境、化学微环境和物理微环境对免疫细胞黏附与迁移的调控机制。     

免疫微环境对肿瘤干细胞影响研究进展

肿瘤干细胞是肿瘤组织中一小群特殊的未分化的细胞,由于其对化疗药耐受及致瘤潜能,被认为是造成肿瘤发生、复发和转移的根源,所以深入了解肿瘤干细胞特性对提高肿瘤治疗效率有着重要临床意义.肿瘤微环境中的免疫细胞及其分泌的分子与肿瘤干细胞之间存在复杂的相互作用,可以维持肿瘤干细胞的干性及自我更新能力.目前,肿瘤免疫微环境对肿瘤干细胞的影响、肿瘤干细胞对免疫微环境的塑造作用以及靶向肿瘤干细胞或免疫微环境等研究,是肿瘤干细胞研究领域的热点问题.本文就免疫微环境对肿瘤干细胞的影响、靶向肿瘤干细胞及微环境治疗的研究进展进行了综述.     

TGF-β对肿瘤微环境中免疫监视及细胞外基质的调控作用

转化生长因子β(transforming growth factorβ,TGF-β)是一种多功能的细胞因子,能够调控细胞增殖、分化、黏附、迁移及凋亡等行为,在胚胎发育过程和成体组织稳态维持中发挥重要的作用。而在许多疾病状态下,特别是在癌症中,TGF-β不仅能够影响肿瘤细胞的增殖与转移,其对于肿瘤微环境的调控与塑造也受到越来越多的关注。肿瘤微环境是指肿瘤在发生和发展过程中所处的内环境,由肿瘤细胞本身、相邻正常组织中的间质细胞,以及这些细胞所释放的众多细胞因子等共同组成。肿瘤微环境是肿瘤发展的重要机制,也是肿瘤临床治疗领域亟待探索的关键问题。TGF-β是调节肿瘤微环境组成和功能的主要参与者之一。在本综述中,将着重讨论TGF-β对于肿瘤微环境中的免疫监视机制及肿瘤细胞外基质的主要影响。即TGF-β对于构成先天性和获得性抗肿瘤免疫应答的各种类群的免疫细胞具有广泛的调控作用,从而削弱宿主的肿瘤免疫监视功能。同时,TGF-β通过促进肿瘤相关成纤维细胞的产生,以及肿瘤细胞外基质的纤维化,有助于肿瘤的恶变和转移。此外,还介绍了通过阻断肿瘤微环境中TGF-β信号通路进行肿瘤治疗的主要策略及独特优势。而未来进一步解析TGF-β信号在肿瘤微环境中的复杂调控作用,并建立有效的靶向干预方法对于开发高效的抗肿瘤药物具有重要的意义。     

树突状细胞在缺氧微环境中的研究进展

胚胎发育,高原生活,体育锻炼以及严重创伤、心血管疾病和肿瘤等都可能引起缺氧微环境,从而导致机体生理和病理特征的改变.缺氧微环境可通过免疫细胞直接影响机体免疫功能.树突状细胞(dendritic cell,DC)是体内最强的抗原递呈细胞(antigen presenting cell,APC),可有效连接天然免疫和适应性...     

GSDMs家族蛋白介导细胞焦亡在抗肿瘤免疫中的作用

细胞焦亡是一种调节性细胞死亡方式。Gasdermine（GSDMs）是一类执行细胞焦亡的胞内蛋白质。虽然GSDMs表达后的完整蛋白质不具有活性,但能被某些蛋白水解酶激活。被激活的GSDMs N端在质膜上穿孔,导致细胞裂解,引起细胞内的促炎分子及损伤相关分子模式（danger-associated molecular patterns,DAMPs）迅速有效地从焦亡细胞中释放,从而引发炎症和免疫反应。焦亡细胞促进抗肿瘤免疫作用可能涉及细胞毒性T淋巴细胞对肿瘤细胞的杀伤。本文介绍GSDMs介导的细胞焦亡及细胞焦亡过程中引发促炎症和免疫反应的关键分子,并且探讨细胞焦亡对肿瘤治疗的有利及不利因素,以期更好地了解细胞焦亡对肿瘤免疫微环境的影响及对肿瘤免疫治疗的作用,有助于促进恶性肿瘤治疗策略的改进。     

Mast Cells Mobilize Myeloid-Derived Suppressor Cells and Treg Cells in Tumor Microenvironment via IL-17 Pathway in Murine Hepatocarcinoma Model

Tumor immunosuppression is commonly braided with chronic inflammation during tumor development. However, the relationship between immunosuppression and inflammation in tumor microenvironment is still unclear. We have demonstrated that mast cells are accumulated and exacerbate the inflammation and immunosuppression in tumor microenvironment via SCF/c-kit signaling pathway. Here, we further elucidate the underlying mechanism, which involves both myeloid-derived suppressor cells (MDSCs) and regulatory T (Treg) cells. Our data showed that mast cells mobilized the infiltration of MDSCs to tumor and induced the production of IL-17 by MDSCs; MDSCs-derived IL-17 indirectly attracted Treg cells, enhanced their suppressor function, and induced the IL-9 production by Treg cells; in turn, IL-9 strengthened the survival and protumor effect of mast cells in tumor microenvironment. Our findings disclose a closed loop among mast cells, MDSCs and Treg cells in tumor microenvironment, which provides a new insight into the paralleled developments of inflammation and immunosuppression in tumor microenvironment. Based on these findings, we propose that targeting tumor inflammation might be a potential strategy to reverse the immunosuppression of tumor microenvironment, thus facilitating cancer immunotherapy.     

CC chemokine ligand 2 (CCL2) promotes prostate cancer tumorigenesis and metastasis

CCL2 is a chemokine known to recruit monocytes and macrophages to sites of inflammation. A growing body of research suggests CCL2 is progressively overexpressed in tumor beds and may play a role in the clinical progression of solid tumors. Cancer cells derived from several solid tumor types demonstrate functional receptors for CCL2, suggesting this chemokine may achieve tumorigenicity through direct effects on malignant cells; however, a variety of normal host cells that co-exist with cancer in the tumor microenvironment also respond to CCL2. These cells include macrophages, osteoclasts, endothelial cells, T-lymphocytes, and myeloid-derived immune suppressor cells (MDSCs). CCL2 mediated interactions between normal and malignant cells in the tumor microenvironment and plays a multi-faceted role in tumor progression.     

Isolation of immune cells from primary tumors

Tumors create a unique immunosuppressive microenvironment (tumor microenvironment, TME) whereby leukocytes are recruited into the tumor by various chemokines and growth factors. However, once in the TME, these cells lose the ability to promote anti-tumor immunity and begin to support tumor growth and down-regulate anti-tumor immune responses. Studies on tumor-associated leukocytes have mainly focused on cells isolated from tumor-draining lymph nodes or spleen due to the inherent difficulties in obtaining sufficient cell numbers and purity from the primary tumor. While identifying the mechanisms of cell activation and trafficking through the lymphatic system of tumor bearing mice is important and may give insight to the kinetics of immune responses to cancer, in our experience, many leukocytes, including dendritic cells (DCs), in tumor-draining lymph nodes have a different phenotype than those that infiltrate tumors. Furthermore, we have previously demonstrated that adoptively-transferred T cells isolated from the tumor-draining lymph nodes are not tolerized and are capable of responding to secondary stimulation in vitro unlike T cells isolated from the TME, which are tolerized and incapable of proliferation or cytokine production. Interestingly, we have shown that changing the tumor microenvironment, such as providing CD4(+) T helper cells via adoptive transfer, promotes CD8(+) T cells to maintain pro-inflammatory effector functions. The results from each of the previously mentioned studies demonstrate the importance of measuring cellular responses from TME-infiltrating immune cells as opposed to cells that remain in the periphery. To study the function of immune cells which infiltrate tumors using the Miltenyi Biotech isolation system, we have modified and optimized this antibody-based isolation procedure to obtain highly enriched populations of antigen presenting cells and tumor antigen-specific cytotoxic T lymphocytes. The protocol includes a detailed dissection of murine prostate tissue from a spontaneous prostate tumor model (TRansgenic Adenocarcinoma of the Mouse Prostate -TRAMP) and a subcutaneous melanoma (B16) tumor model followed by subsequent purification of various leukocyte populations.     

肥大细胞在肿瘤发生发展中的作用

肥大细胞是人体主要免疫细胞之一,因其作为导致过敏反应发生的最直接效应细胞而著称.肥大细胞最主要的结构特征为其胞内含有大量嗜碱性颗粒,该颗粒内又富含种类众多的生物活性物质,包括组胺、血管内皮生长因子(vascular endothelial growth factor,VEGF)、成纤维细胞生长因子(fibroblast...     

Cutting edge: Th17 and regulatory T cell dynamics and the regulation by IL-2 in the tumor microenvironment

Th17 cells play an active role in inflammation and autoimmune diseases. However, the nature and regulation of Th17 in the context of tumor immunity remain unknown. In this study, we show that parallel to regulatory T (Treg) cells, IL-17(+) CD4(+) and CD8(+) T cells are kinetically induced in multiple tumor microenvironments in mice and humans. Treg cells play a crucial role in tumor immune pathogenesis and temper immune therapeutic efficacy. IL-2 is crucial for the production and function of Treg cells. We now show that IL-2 reduces IL-17(+) T cell differentiation in the tumor microenvironment accompanied with an enhanced Treg cell compartment in vitro and in vivo. Altogether, our work demonstrates a dynamic differentiation of IL-17(+) T cells in the tumor microenvironment, reveals a novel role for IL-2 in controlling the balance between IL-17(+) and Treg cells, and provides new insight of IL-17(+) T cells in tumor immune pathology and therapy.     

Inflammation: A driving force speeds cancer metastasis

It has been increasingly recognized that tumor microenvironment plays an important role in carcinogenesis. Inflammatory component is present and contributes to tumor proliferation, angiogenesis, metastasis, and resistance to hormonal and chemotherapy. This review highlights the role of inflammation in the tumor metastasis. We focus on the function of proinflammatory factors, particularly cytokines during tumor metastasis. Understanding of the mechanisms by which inflammation contributes to metastasis will lead to innovative approach for treating cancer.

How tumor spreads remains an enigma and has received great attention in recent years, as metastasis is the major cause of cancer mortality. The complex and highly selective metastatic cascade not only depends on the intrinsic properties of tumor cells but also the microenvironment that they derive from. An inflammatory milieu consisting of infiltrated immune cells and their secretory cytokines, chemokines, and growth factors contribute significantly to the invasive and metastatic traits of cancer cells. Here, we review new insights into the molecular pathways that link inflammation in the tumor microenvironment to metastasis.     

Systems Analysis of a Mouse Xenograft Model Reveals Annexin A1 as a Regulator of Gene Expression in Tumor Stroma

Annexin A1 is a multi functional molecule which is involved in inflammation, innate and adaptive immune systems, tumor progression and metastasis. We have previously showed the impaired tumor growth, metastasis, angiogenesis and wound healing in annexin A1 knockout mice. While tumor is a piece of heterogeneous mass including not only malignant tumor cells but also the stroma, the importance of the tumor stroma for tumor progression and metastasis is becoming increasingly clear. The tumor stroma is comprised by various components including extracellular matrix and non-malignant cells in the tumor, such as endothelial cells, fibroblasts, immune cells, inflammatory cells. Based on our previous finding of pro-angiogenic functions for annexin A1 in vascular endothelial cell sprouting, wound healing, tumor growth and metastasis, and the previously known properties for annexin A1 in immune cells and inflammation, this study hypothesized that annexin A1 is a key functional player in tumor development, linking the various components in tumor stroma by its actions in endothelial cells and immune cells. Using systems analysis programs commercially available, this paper further compared the gene expression between tumors from annexin A1 wild type mice and annexin A1 knockout mice and found a list of genes that significantly changed in the tumor stroma that lacked annexin A1. This revealed annexin A1 to be an effective regulator in tumor stroma and suggested a mechanism that annexin A1 affects tumor development and metastasis through interaction with the various components in the microenvironment surrounding the tumor cells.