Anti-CTLA-4 and anti-PD-1 immunotherapies repress tumor progression in preclinical breast and colon model with independent regulatory T cells response

The recent development of immunotherapy represents a significant breakthrough in cancer therapy. Several immunotherapies provide robust efficacy gains in a wide variety of cancers. However, in some patients the immune checkpoint blockade remains ineffective due to poor therapeutic response and tumor relapse. An improved understanding of the mechanisms underlying tumor-immune system interactions can improve clinical management of cancer. Here, we report preclinical data evaluating two murine antibodies corresponding to recent FDA-approved antibodies for human therapy, e.g. anti-CTLA-4 and anti-PD-1. We demonstrated in two mouse syngeneic grafting models of triple negative breast or colon cancer that the two antibodies displayed an efficient anticancer activity, which is enhanced by combination treatment in the breast cancer model. We also demonstrated that CTLA-4 targeting reduced metastasis formation in the colon cancer metastasis model. In addition, using cytometry-based multiplex analysis, we showed that anti-CTLA-4 and anti-PD-1 affected the tumor immune microenvironment differently and in particular the tumor immune infiltration. This work demonstrated anti-cancer effect of CTLA-4 or PD-1 blockade on mouse colon and triple negative breast and on tumor-infiltrating immune cell subpopulations that could improve our knowledge and benefit the breast and colon cancer tumor research community.     

Emerging role of metabolic reprogramming in tumor immune evasion and immunotherapy

Mounting evidence has revealed that the therapeutic efficacy of immunotherapies is restricted to a small portion of cancer patients. A deeper understanding of how metabolic reprogramming in the tumor microenvironment(TME) regulates immunity remains a major challenge to tumor eradication. It has been suggested that metabolic reprogramming in the TME may affect metabolism in immune cells and subsequently suppress immune function. Tumor cells compete with infiltrating immune cells for nutrients and metabolites. Notably, the immunosuppressive TME is characterized by catabolic and anabolic processes that are critical for immune cell function, and elevated inhibitory signals may favor cancer immune evasion. The major energy sources that supply different immune cell subtypes also undergo reprogramming. We herein summarize the metabolic remodeling in tumor cells and different immune cell subtypes and the latest advances underlying the use of metabolic checkpoints in antitumor immunotherapies. In this context, targeting both tumor and immune cell metabolic reprogramming may enhance therapeutic efficacy.     

Single-cell analysis of tumors: Creating new value for molecular biomarker discovery of cancer stem cells and tumor-infiltrating immune cells

Biomarker-driven individualized treatment in oncology has made tremendous progress through technological developments, new therapeutic modalities and a deeper understanding of the molecular biology for tumors, cancer stem cells and tumor-infiltrating immune cells. Recent technical developments have led to the establishment of a variety of cancer-related diagnostic, prognostic and predictive biomarkers. In this regard, different modern OMICs approaches were assessed in order to categorize and classify prognostically different forms of neoplasia. Despite those technical advancements, the extent of molecular heterogeneity at the individual cell level in human tumors remains largely uncharacterized. Each tumor consists of a mixture of heterogeneous cell types. Therefore, it is important to quantify the dynamic cellular variations in order to predict clinical parameters, such as a response to treatment and or potential for disease recurrence. Recently, single-cell based methods have been developed to characterize the heterogeneity in seemingly homogenous cancer cell populations prior to and during treatment. In this review, we highlight the recent advances for single-cell analysis and discuss the challenges and prospects for molecular characterization of cancer cells, cancer stem cells and tumor-infiltrating immune cells.     

肿瘤精准免疫诊断综合评估

近年来,肿瘤免疫治疗(cancer immunotherapies)已成为晚期恶性肿瘤治疗的重要手段之一。肿瘤免疫治疗并不直接攻击癌细胞,而是通过调节人体自身免疫系统来抗击肿瘤,有望像抗生素改变抗感染治疗一样改变肿瘤治疗范式。抗PD-1/L1和抗CTLA-4抗体药物作为肿瘤免疫治疗的代表药物,使晚期癌症患者五年生存率达成了数倍的提升,被认为是真正有希望治愈癌症的治疗方式。然而,肿瘤免疫治疗只对部分患者有效,并且存在耐药、超进展、不良反应等问题。如何准确筛选出最有可能从治疗中获益的人群成为肿瘤免疫治疗研究中的一个重大挑战。目前有多个与免疫治疗相关的生物标志物正在研究中,并且有望被用于临床筛选治疗获益人群;但这些生物标记物也存在很多缺陷。未来,围绕免疫治疗敏感性和副反应的多项指标综合评估可能成为一个趋势。     

Dendritic Cell-Based Immunotherapy for Solid Tumors

As a treatment for solid tumors, dendritic cell (DC)-based immunotherapy has not been as effective as expected. Here, we review the reasons underlying the limitations of DC-based immunotherapy for solid tumors and ask what can be done to improve immune cell-based cancer therapies. Several reports show that, rather than a lack of immune induction, the limited efficacy of DC-based immunotherapy in cases of renal cell carcinoma (RCC) likely results from inhibition of immune responses by tumor-secreted TGF-β and an increase in the number of regulatory T (Treg) cells in and around the solid tumor. Indeed, unlike DC therapy for solid tumors, cytotoxic T lymphocyte (CTL) responses induced by DC therapy inhibit tumor recurrence after surgery; CTL responses also limit tumor metastasis induced by additional tumor-challenge in RCC tumor-bearing mice. Here, we discuss the mechanisms underlying the poor efficacy of DC-based therapy for solid tumors and stress the need for new and improved DC immunotherapies and/or combination therapies with killer cells to treat resistant solid tumors.     

Application of single-cell technology in cancer research

In this review, we have outlined the application of single-cell technology in cancer research. Single-cell technology has made encouraging progress in recent years and now provides the means to detect rare cancer cells such as circulating tumor cells and cancer stem cells. We reveal how this technology has advanced the analysis of intratumor heterogeneity and tumor epigenetics, and guided individualized treatment strategies. The future prospects now are to bring single-cell technology into the clinical arena. We believe that the clinical application of single-cell technology will be beneficial in cancer diagnostics and treatment, and ultimately improve survival in cancer patients.     

综述:髓系衍生的抑制性细胞与肿瘤免疫耐受关系的研究进展

髓系衍生的抑制性细胞(myeloid-derived suppressor cells,MDSCs),是在肿瘤等病理因素的作用下髓系细胞发生分化障碍所产生的不同阶段髓系祖细胞的集合,具有广谱而强大的免疫抑制功能,是免疫系统的重要负性调节组件之一.研究表明:肿瘤微环境中的多种细胞因子或生长因子可通过激活相应的信号通路促进MDSCs扩增及活化,MDSCs进而通过多种机制抑制包括T细胞在内的多种免疫细胞的功能而促进肿瘤个体免疫耐受的发生.临床研究表明:肿瘤患者体内MDSCs的水平与肿瘤临床病程进展密切相关,基于MDSCs的免疫治疗也有望成为肿瘤免疫治疗的新策略.本文主要介绍了肿瘤中MDSCs的表型鉴定、扩增及活化机制、发挥免疫抑制作用的途径及机制、肿瘤中MDSCs的临床意义以及本领域需要解决的问题,以期对MDSCs在肿瘤免疫耐受中的作用进展提供参考.     

Dissecting tumor responsiveness to immunotherapy: the experience of peptide-based melanoma vaccines

Recent years have witnessed important breakthroughs in our understanding of tumor immunology. A variety of immunotherapeutic strategies has shown that immune manipulation can induce the regression of established cancer in humans. The identification of the genes encoding tumor-associated antigens (TAA) and the development of means for immunizing against these antigens have opened new avenues for the development of an effective anticancer immunotherapy. However, an efficient immune response against tumor requires an intricate cross-talk between cancer and immune system cells, which is still poorly understood. Only when the molecular basis underlying tumor susceptibility to an immune response is deciphered could new therapeutic strategies be designed to fit biologically defined mechanisms of cancer immune rejection. In this article, we address some of the critical issues that have been identified in cancer immunotherapy, in part from our own studies on immune therapies in melanoma patients treated with peptide-based vaccination regimens. This is not meant to be a comprehensive overview of the immunological phenomena accompanying cancer patient vaccination but rather emphasizes some emergent findings, puzzling controversies and unanswered questions that characterize this complex field of oncology. In addition to reviewing the main immunological concepts underlying peptide-based vaccination, we also review the available data regarding naturally occurring and therapeutically induced anticancer immune response, both at the peripheral and intratumoral level. The hypothesized role of innate immunity in predetermining tumor responsiveness to immunotherapeutic manipulation is also discussed.     

The thin red line between the immune system and cancer evolution

The cancer immunoediting theory describes the dual ability of endogenous antitumor immunity to inhibit or promote progressing cancers. Tumor-specific neoantigens arising from somatic mutations serve as targets for the endogenous T-cell-mediated antitumor immunity and therefore possess a crucial role for tumor development. Additionally, targeting these molecules is conceptually appealing because neoantigens are not expressed in healthy tissue and therefore confer less toxicity and greater specificity when used in therapeutic interventions. Moreover, intratumor neo-antigenic heterogeneity is believed to play a pivotal role in the activation of adaptive immunity and in the efficacy of immunotherapies that are based on immune checkpoint inhibition. In this respect, mutual interactions between tumor cells and immune lymphocytes regulate the levels of antitumor immunity, but also shape tumor heterogeneity through the selective outgrowth of tumor subclones. Therefore, the exploration of the mechanistic pathways and the identification of the genomic aberrations underlying the clonal evolution of tumors is considered mandatory for improving the clinical outcomes of therapies, as it will assist in the selection of the appropriate therapeutic decisions so as to delay, avoid, or overcome resistance through the identification of the most effective therapeutic strategies.     

GM-CSF-secreting cancer immunotherapies: preclinical analysis of the mechanism of action

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting tumor cell immunotherapies have demonstrated long-lasting, and specific anti-tumor immune responses in animal models. The studies reported here specifically evaluate two aspects of the immune response generated by such immunotherapies: the persistence of irradiated tumor cells at the immunization site, and the breadth of the immune response elicited to tumor associated antigens (TAA) derived from the immunotherapy. To further define the mechanism of GM-CSF-secreting cancer immunotherapies, immunohistochemistry studies were performed using the B16F10 melanoma tumor model. In contrast to previous reports, our data revealed that the irradiated tumor cells persisted and secreted high levels of GM-CSF at the injection site for more than 21 days. Furthermore, dense infiltrates of dendritic cells were observed only in mice treated with GM-CSF-secreting B16F10 cells, and not in mice treated with unmodified B16F10 cells with or without concurrent injection of rGM-CSF. In addition, histological studies also revealed enhanced neutrophil and CD4+ T cell infiltration, as well as the presence of apoptotic cells, at the injection site of mice treated with GM-CSF-secreting tumor cells. To evaluate the scope of the immune response generated by GM-CSF-secreting cancer immunotherapies, several related B16 melanoma tumor cell subclones that exist as a result of genetic drift in the original cell line were used to challenge mice previously immunized with GM-CSF-secreting B16F10 cells. These studies revealed that GM-CSF-secreting cancer immunotherapies elicit T cell responses that effectively control growth of related but antigenically distinct tumors. Taken together, these studies provide important new insights into the mechanism of action of this promising novel cancer immunotherapy. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

单细胞测序技术在肝脏疾病的应用与展望

新兴的单细胞测序技术能够从单细胞水平揭示基因组、转录组和表观遗传学等分子水平发生的基因变异与表观修饰状态,也可用于鉴定新的细胞类型和表面标记物。这将帮助人们探明疾病发生时细胞基因、转录或表观修饰方面的变化,了解细胞之间的联系,以及深入理解肿瘤异质性。目前,单细胞测序技术已用于多种疾病的研究,其在肝脏疾病,包括肝硬化、肝癌中已有相关成果。于此,综述了单细胞测序技术在肝脏发育及肝病中的应用,讨论了肝脏疾病发生的内在机制以及该技术仍存在的问题,提出可能的解决方案,如发展三维单细胞测序技术将更能帮助人们深刻理解肝脏疾病发生机制。     

Multi-Stability and Multi-Instability Phenomena in a Mathematical Model of Tumor-Immune-Virus Interactions

Recent advances in virology, gene therapy, and molecular and cell biology have provided insight into the mechanisms through which viruses can boost the anti-tumor immune response, or can infect and directly kill tumor cells. A recent experimental report (Bridle et al. in Molec. Ther. 18(8):1430–1439, 2010) showed that a sequential treatment approach that involves two viruses that carry the same tumor antigen leads to an improved anti-tumor response compared to the effect of each virus alone. In this article, we derive a mathematical model to investigate the anti-tumor effect of two viruses, and their interactions with the immune cells. We discuss the conditions necessary for permanent tumor elimination and, in this context, we stress the importance of investigating the long-term effect of non-linear interactions. In particular, we discuss multi-stability and multi-instability, two complex phenomena that can cause abrupt transitions between different states in biological and physical systems. In the context of cancer immunotherapies, the transitions between a tumor-free and a tumor-present state have so far been associated with the multi-stability phenomenon. Here, we show that multi-instability can also cause the system to switch from one state to the other. In addition, we show that the multi-stability is driven by the immune response, while the multi-instability is driven by the presence of the virus.     

The therapeutic potential of immune cell-derived exosomes as an alternative to adoptive cell transfer

Adoptive cell transfer (ACT), a form of cell-based immunotherapy that eliminates cancer by restoring and strengthening the body’s immune system, has revolutionized cancer treatment. ACT entails intravenous transfer of either tumor-resident or peripheral blood-modified immune cells into cancer patients to mediate anti-tumor response. Although these immune cells control and eradicate cancer via enhanced cytotoxicity against specific tumor antigens, several side effects have been frequently reported in clinical trials. Recently, exosomes, potential cell-free therapeutics, have emerged as an alternative to cell-based immunotherapies, due to their higher stability under same storage condition, lower risk of GvHD and CRS, and higher resistance to immunosuppressive tumor microenvironment. Exosomes, which are nano-sized lipid vesicles, are secreted by living cells, including immune cells. Exosomes contain proteins, lipids, and nucleic acids, and the functional role of each exosome is determined by the specific cargo derived from parental cells. Exosomes derived from cytotoxic effectors including T cells and NK cells exert anti-tumor effects via proteins such as granzyme B and FasL. In this mini-review, we describe the current understanding of the ACT and immune cell-derived exosomes and discuss the limitations of ACT and the opportunities for immune cell-derived exosomes as immune therapies.     

单细胞测序技术及其在乳腺癌研究中的应用

乳腺癌是起源于乳腺各级导管和乳腺上皮细胞,由增生到不典型增生而逐步发展成原位癌、早期浸润癌至浸润性癌的一种恶性肿瘤。传统高通量测序技术对乳腺癌的研究主要是鉴定与乳腺癌发生发展相关的"驱动基因",但是对于乳腺癌基因组结构变化以及亚克隆的鉴定等存在一定的局限性,并且忽略了乳腺癌肿瘤细胞之间的异质性。近年来兴起的单细胞测序技术是以单个细胞为研究对象,对基因拷贝和基因表达等数据进行分析,探究乳腺癌的细胞组成、细胞状态和细胞命运,绘制乳腺癌生态系统图谱,对临床患者进行精准分层,为实现个体化治疗提供支持。同时,还可以揭示乳腺癌与T细胞、巨噬细胞等免疫细胞间的相关性,为发现乳腺癌新的治疗靶点、免疫检查点等提供参考。本文对单细胞测序技术及其在乳腺癌研究中的应用和研究进展进行了综述,以期为单细胞测序技术的进一步发展提供参考,同时为理解乳腺癌的发病机制和免疫治疗提供基础支持。