Advancement of chimeric antigen receptor-natural killer cells targeting hepatocellular carcinoma

With the advance of genome engineering technology,chimeric antigen receptors(CARs)-based immunotherapy has become an emerging therapeutic strategy for tumors.Although initially designed for T cells in tumor immunotherapy,CARs have been exploited to modify the function of natural killer(NK)cells against a variety of tumors,including hepatocellular carcinoma(HCC).CAR-NK cells have the potential to sufficiently kill tumor antigen-expressing HCC cells,independent of major histocompatibility complex matching or prior priming.In this review,we summarize the recent advances in genetic engineering of CAR-NK cells against HCC and discuss the current challenges and prospects of CAR-NK cells as a revolutionary cellular immunotherapy against HCC.

Human CD4- CD8- Invariant Natural Killer T Cells Promote IgG Secretion from B Cells Stimulated by Cross-Linking of Their Antigen Receptors

Immunoglobulin (Ig) M production can be induced by the interaction of thymus-independent type-2 (TI-2) antigen (Ag) with B cell Ag receptors (BCRs) without the involvement of conventional T cells;for IgG production through the same process, however, a second signal is required. Previous studies have reported that invariant natural killer T (iNKT) cells may be responsible for the second signal involved in IgG production. In the present study, we addressed whether human iNKT cells could participate in the production of Ig against TI-2 Ag in vitro. Two major distinct subsets of human iNKT cells, CD4+ CD8β- (CD4) and CD4- CD8β- [double negative (DN)] cells, were generated from peripheral blood monocytes from a healthy volunteer. BCR engagement, triggered by anti-IgM antibody stimulation, examined here as a model of BCR engagement triggered by TI-2 Ag, induced abundant IgM production by B cells. Both CD4 and DN iNKT cells reduced IgM production and conversely enhanced IgG production in a dose-dependent manner. In addition, IgG production by CD19+CD27- (naïve) and CD19+CD27+ (memory) B cells was predominantly promoted by DNiNKT cells rather than CD4 iNKT cells;nevertheless, IgM production by both B cell subsets was similarly reduced by either subset of iNKT cells. These results suggest that the DN iNKT subsets may preferentially promote Ig class switching by B cells upon stimulation with TI-2 Ag.

HBsAg stimulates NKG2D receptor expression on natural killer cellsand inhibits hepatitis C virus replication

Background: Higher hepatitis B surface antigen(HBs Ag) facilitates hepatitis C virus(HCV) clearance in patients with hepatitis B virus(HBV)/HCV co-infection. We investigated the effect of exogenous HBs Ag on the inhibition of HCV replication mediated by natural killer(NK) cells.Methods: After isolated from peripheral blood of 42 chronic hepatitis B(CHB) patients and 16 healthy individuals, NK cells were co-cultured with HCV-infected Huh7 cells, respectively, with or without HBs Ag.Three days later, the co-cultured supernatants were collected and HCV RNA levels were measured by realtime quantitative PCR. NKG2 D, NKp46 and NKG2 A expression levels were measured by flow cytometry.NKG2 D on NK cells from CHB responsive subgroup was blocked and HCV RNA levels were examined again.Results: HCV RNA levels in the co-cultured system were significantly reduced by NK cells isolated from healthy donors(P < 0.01) but not from CHB patients. However, HCV RNA levels in CHB cultures were significantly decreased following HBs Ag addition(P < 0.05), whereas no such effect was seen in control cultures. No significant difference was observed in basic NKG2 D expression between the CHB patients and healthy donors. On NK cells from CHB patients, the expression of NKG2 D was increased significantly by HBs Ag stimulation(P < 0.01), and higher than that from healthy controls(P < 0.05). HCV RNA levels were increased significantly after the blockage of NKG2 D on NK cells from responsive CHB patients in the co-cultured system(P < 0.05).Conclusion: Exogenous HBs Ag stimulated NKG2 D expression on NK cells from CHB patients which inhibit HCV replication, suggesting that HBs Ag may facilitate the clearance of HCV in patients with HBV/HCV co-infection.

Natural Killer Cell-Based Immunotherapy for Cancer: Advances and Prospects

Natural killer (NK) cells are key innate immune cells that provide the first line of defense against viral infection and cancer. Although NK cells can discriminate between "self" and "non-self," recognize abnormal cells, and eliminate transformed cells and malignancies in real time, tumors develop several strategies to escape from NK cell attack. These strategies include upregulating ligands for the inhibitory receptors of NK cells and producing soluble molecules or immunosuppressive factors. Various types of NK cells are currently being applied in clinical trials, including autologous or allogeneic NK cells, umbilical cord blood (UCB) or induced pluripotent stem cell (iPSC)-derived NK cells, memory-like NK cells, and NK cell line NK-92 cells, for the treatment of different types of tumors. Chimeric antigen receptors (CARs)-NK cells have recently shown great potential due to their redirect specificity and effective antitumor activity. In this review, we summarize the mechanisms of tumor escape from NK cell recognition, the current status and advanced progress of NK cell-based immunotherapy, ways of enhancing the antitumor capacity of NK cells in vivo, and major challenges for clinical practice in this field.

Chimeric antigen receptor- and natural killer cell receptor-engineered innate killer cells in cancer immunotherapy

Chimeric antigen receptor(CAR)-engineered T-cell(CAR-T)therapy has demonstrated impressive therapeutic efficacy against hematological malignancies,but multiple challenges have hindered its application,particularly for the eradication of solid tumors.Innate killer cells(IKCs),particularly NK cells,NKT cells,andγδT cells,employ specific antigen-independent innate tumor recognition and cytotoxic mechanisms that simultaneously display high antitumor efficacy and prevent tumor escape caused by antigen loss or modulation.IKCs are associated with a low risk of developing GVHD,thus offering new opportunities for allogeneic“off-the-shelf”cellular therapeutic products.The unique innate features,wide tumor recognition range,and potent antitumor functions of IKCs make them potentially excellent candidates for cancer immunotherapy,particularly serving as platforms for CAR development.In this review,we first provide a brief summary of the challenges hampering CAR-T-cell therapy applications and then discuss the latest CAR-NK-cell research,covering the advantages,applications,and clinical translation of CAR-and NK-cell receptor(NKR)-engineered IKCs.Advances in synthetic biology and the development of novel genetic engineering techniques,such as gene-editing and cellular reprogramming,will enable the further optimization of IKC-based anticancer therapies.

Engineered human pluripotent stem cell-derived natural killer cells with PD-L1 responsive immunological memory for enhanced immunotherapeutic efficacy

Adoptive chimeric antigen receptor(CAR)-engineered natural killer(NK)cells have shown promise in treating various cancers.However,limited immunological memory and access to sufficient numbers of allogenic donor cells have hindered their broader preclinical and clinical applications.Here,we first assess eight different CAR constructs that use an anti-PD-L1 nanobody and/or universal anti-fluorescein(FITC)single-chain variable fragment(scFv)to enhance antigen-specific proliferation and anti-tumor cytotoxicity of NK-92 cells against heterogenous solid tumors.We next genetically engineer human pluripotent stem cells(hPSCs)with optimized CARs and differentiate them into functional dual CAR-NK cells.The tumor microenvironment responsive anti-PD-L1 CAR effectively promoted hPSC-NK cell proliferation and cytotoxicity through antigen-dependent activation of phosphorylated STAT3(pSTAT3)and pSTAT5 signaling pathways via an intracellular truncated IL-2 receptorβ-chain(ΔIL-2Rβ)and STAT3-binding tyrosine-X-X-glutamine(YXXQ)motif.Anti-tumor activities of PD-L1-induced memory-like hPSC-NK cells were further boosted by administering a FITC-folate bi-specific adapter that bridges between a programmable anti-FITC CAR and folate receptor alpha-expressing breast tumor cells.Collectively,our hPSC CAR-NK engineering platform is modular and could constitute a realistic strategy to manufacture off-the-shelf CAR-NK cells with immunological memory-like phenotype for targeted immunotherapy.

Targeting immune checkpoints:how to use natural killer cells for fighting against solid tumors

Natural killer(NK)cells are unique innate immune cells that mediate antiviral and anti-tumor responses.Thus,they might hold great potential for cancer immunotherapy.NK cell adoptive immunotherapy in humans has shown modest efficacy.In particular,it has failed to demonstrate therapeutic efficiency in the treatment of solid tumors,possibly due in part to the immunosuppressive tumor microenvironment(TME),which reduces NK cell immunotherapy’s efficiencies.It is known that immune checkpoints play a prominent role in creating an immunosuppressive TME,leading to NK cell exhaustion and tumor immune escape.Therefore,NK cells must be reversed from their dysfunctional status and increased in their effector roles in order to improve the efficiency of cancer immunotherapy.Blockade of immune checkpoints can not only rescue NK cells from exhaustion but also augment their robust anti-tumor activity.In this review,we discussed immune checkpoint blockade strategies with a focus on chimeric antigen receptor(CAR)-NK cells to redirect NK cells to cancer cells in the treatment of solid tumors.

肝细胞癌过继细胞疗法研究进展

肝细胞癌是严重威胁人类生存的一类疾病,中国肝细胞癌死亡率居世界第三。由于肝细胞癌发病早期无特异性症状,晚期的治疗方案又存在复发率高等的种种弊端,因此寻找行之有效的治疗新方法迫在眉睫。过继细胞疗法是一种细胞免疫疗法,在肝脏多样化和复杂的免疫微环境中,通过结合肿瘤特异性抗原或是非特异性的调节免疫平衡,过继细胞疗法在肝细胞癌的治疗中逐渐发挥出优势。在这篇综述中我们阐述了肝细胞癌靶向治疗常用生物标志物的形态结构及信号通路,探讨总结了近年来过继细胞疗法治疗肝细胞癌的研究手段及取得的临床效果,并对接下来的研究方向进行了展望。

非小细胞肺癌患者血清CA211水平和NK细胞数与预后相关

目的 探究非小细胞肺癌(NSCLC)患者血清糖类抗原211(CA211)表达水平和自然杀伤(NK)细胞数与预后的相关性。方法 选取杭州师范大学附属医院2019年6月至2022年7月收治的132例NSCLC患者作为实验组,另选取同期收治的132例肺部良性病变患者作为对照组。从检验科收集数据分析NSCLC患者血清CA211表达水平和NK细胞数与患者预后关系以及影响NSCLC患者预后的相关因素。结果 实验组中性粒细胞/淋巴细胞值(NLR值)和血清CA211表达水平高于对照组(P<0.05),NK细胞数低于对照组(P<0.05);实验组血清CA211表达水平和NK细胞数呈负相关(r=-0.405,P<0.001);不同血清CA211表达水平和NK细胞数的患者淋巴结转移情况以及TNM分期存在显著性差异(P<0.05);CA211低表达者1年生存率高于CA211高表达者(P<0.05),NK细胞高水平者1年生存率高于NK细胞低水平者(P<0.05);淋巴结转移、TNM分期、CA211是影响NSCLC患者预后的危险因素(P<0.05),NK细胞是NSCLC患者预后的保护因素(P<0.05)。结论 NSCLC患者血清CA211表达水平及NK细胞数与临床病理特征及预后有密切联系。

Harnessing natural killer cells to develop next-generation cellular immunotherapy

Cellular immunotherapy harnesses the body’’s own immune system to fight cancer by using engineered T cells,macrophages,or natural killer(NK)cells.Compared to chimeric antigen receptor T(CAR-T)cells that are commonly used to treat hematological malignancies,CAR-NK cells have shown remarkable therapeutic effectiveness while exhibiting enhanced safety,reduced risk of graft-versus-host disease,fewer side effects,and amplified antitumor efficacy.Preclinical trials have unveiled the high potential of adoptive CAR-NK cell therapy to curtail or even eliminate both hematological malignancies and solid tumors in animal models.We brought forth herein the design principle of CAR-NK cells,highlighted the latest progress in the preclinical testing and clinical trials of CAR-NK cells,briefly delved into discussed major roadblocks in CAR-NK therapy,and discussed potential solutions to surmount these challenges.Given the accelerated progress in both basic and translational studies on immune cell engineering,CAR-NK cell therapy promises to become a serious contender and important addition to the next-generation cell-based immunotherapy.

Engineered human pluripotent stem cell-derived natural killer cells: the next frontier for cancer immunotherapy

Adoptive immunotherapy using immune effector cells has revolutionized cancer treatments with approval of two autologous chimeric antigen receptor(CAR)T cell therapies by the US FDA.Clinical trials using natural killer(NK)cell-based adoptive immunotherapy have been shown to be safe and effective for treatment of multiple malignancies,especially acute myelogenous leukemia.However,most of these trails use primary NK cells isolated from peripheral or cord blood which can have donor-dependent variability and can be challenging to genetic engineer to improve antitumor functions,limiting the widespread use of this promising new therapy.NK cells can now be routinely produced from human pluripotent stem cells,both human embryonic stem cells(hESCs)and induced pluripotent stem cells(iPSCs).These pluripotent stem cells are homogenous,easy to genetically modify on a clonal level and can be used as unlimited source of NK cells,making them ideal population to develop standardized,off-the-shelf adoptive NK cell therapy products.In this review,we discuss recent advances of obtaining and expanding hESC and iPSC-derived NK cells and novel genetic engineering strategies that are being applied to improve their antitumor functions.

Revolutionizing gastric cancer treatment:The potential of immunotherapy

Gastric cancer,a prevalent malignancy worldwide,ranks sixth in terms of frequency and third in fatality,causing over a million new cases and 769000 annual deaths.Predominant in Eastern Europe and Eastern Asia,risk factors include family medical history,dietary habits,tobacco use,Helicobacter pylori,and Epstein-Barr virus infections.Unfortunately,gastric cancer is often diagnosed at an advanced stage,leading to a grim prognosis,with a 5-year overall survival rate below 5%.Surgical intervention,particularly with D2 Lymphadenectomy,is the mainstay for early-stage cases but offers limited success.For advanced cases,the National Comprehensive Cancer Network recommends chemotherapy,radiation,and targeted therapy.Emerging immunotherapy presents promise,especially for unresectable or metastatic cases,with strategies like immune checkpoint inhibitors,tumor vaccines,adoptive immunotherapy,and nonspecific immunomodulators.In this Editorial,with regards to the article“Advances and key focus areas in gastric cancer immunotherapy:A comprehensive scientometric and clinical trial review”,we address the advances in the field of immunotherapy in gastric cancer and its future prospects.

Emergence of immunotherapy as a novel way to treat hepatocellular carcinoma

Tumor immunity proceeds through multiple processes, which consist of antigen presentation by antigen presenting cells(APCs) to educate effector cells and destruction by the effector cytotoxic cells. However, tumor immunity is frequently repressed at tumor sites. Malignantly transformed cells rarely survive the attack by the immune system, but cells that do survive change their phenotypes to reduce their immunogenicity. The resultant cells evade the attack by the immune system and form clinically discernible tumors. Tumor microenvironments simultaneously contain a wide variety of immune suppressive molecules and cells to dampen tumor immunity. Moreover, the liver microenvironment exhibits immune tolerance to reduce aberrant immune responses to massively-exposed antigens via the portal vein, and immune dysfunction is frequently associated with liver cirrhosis, which is widespread in hepatocellular carcinoma(HCC) patients. Immune therapy aims to reduce tumor burden, but it is also expected to prevent non-cancerous liver lesions from progressing to HCC, because HCC develops or recurs from noncancerous liver lesions with chronic inflammatory states and/or cirrhosis and these lesions cannot be cured and/or eradicated by local and/or systemic therapies. Nevertheless, cancer immune therapy should augment specific tumor immunity by using two distinct measures: enhancing the effector cell functions such as antigen presentation capacity of APCs and tumor cell killing capacity of cytotoxic cells, and reactivating the immune system in immune-suppressive tumor microenvironments. Here, we will summarize the current status and discuss the future perspective on immune therapy for HCC.

嵌合抗原受体自然杀伤细胞免疫治疗多发性骨髓瘤研究进展

尽管新药的进展使多发性骨髓瘤(MM)患者的生存得到明显改善,但复发难治MM仍缺乏有效治疗方案,且预后差。嵌合抗原受体T细胞(CAR-T)免疫治疗技术虽然在复发难治MM中有不错的疗效,但仍存在局限性,如细胞因子释放综合征、神经毒性等不良反应和脱靶效应等。自然杀伤(NK)细胞作为机体固有免疫的重要成分,在肿瘤免疫监视中发挥重要功能,因此基于NK细胞的嵌合抗原受体自然杀伤细胞(CAR-NK)免疫治疗技术也越来越受到关注。目前CAR-NK免疫治疗MM的研究显示,多个靶点可作为CAR-NK免疫治疗技术特异性治疗靶点,并且在MM细胞及动物实验中也证实其抗肿瘤效应。本文总结了MM肿瘤微环境中NK细胞抗肿瘤机制、生物学特点和功能缺陷情况,以及CAR-NK免疫治疗MM的基础和临床研究进展。

嵌合抗原受体NK细胞在淋巴瘤治疗中的研究进展

过继细胞治疗是近年来肿瘤研究的热点,嵌合抗原受体T细胞(CAR-T)在血液肿瘤中已取得巨大成功,在一定程度上改变了目前肿瘤治疗格局,然而CAR-T疗法的严重不良反应及高昂的治疗费用限制了其在临床的使用范围。自然杀伤细胞(NK)是机体的重要免疫细胞,具有天然的细胞毒性及良好的安全性,基于CAR工程的NK细胞(CAR-NK)在临床前研究中已展现出强大的抗肿瘤活性及安全性,有潜力成为下一代基于CAR平台的免疫细胞疗法。本综述将系统介绍CAR-NK细胞在淋巴瘤中的研究现状。

CAR-NK在实体瘤治疗中的研究进展

肿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。

NK细胞:肿瘤免疫治疗的新兴主力军

自然杀伤(NK)细胞作为人体免疫系统抵御外来病原体入侵的第一道防线,在宿主抵抗病毒感染和肿瘤的先天免疫和获得性免疫防御中发挥重要作用。近年来NK细胞以其独特优势逐渐成为肿瘤免疫治疗的新兴主力军,并在多种血液系统恶性肿瘤治疗中展现出不俗的实力。目前,针对NK细胞相关的免疫治疗手段主要包括免疫检查点抑制剂治疗、嵌合抗原受体NK治疗及双/三特异性杀伤细胞结合因子治疗等。本综述将对当前NK细胞主要的治疗手段及其在肿瘤治疗中所产生的临床效果展开叙述,以期为肿瘤患者的临床治疗提供可靠的理论依据。

嵌合抗原受体NK细胞治疗肝细胞癌的研究进展

肝细胞癌(hepatocellular carcinoma,HCC)是最常见的原发性肝癌。在过去十年中,HCC治疗领域最令人瞩目的当属新型免疫疗法的蓬勃发展。自然杀伤(natural killer,NK)细胞是免疫系统的一员,在抗肿瘤免疫中发挥着至关重要的作用。嵌合抗原受体(chimeric antigen receptor,CAR)-NK细胞疗法是一种新型的肿瘤免疫疗法,通过基因工程技术使NK细胞能够特异性识别肿瘤相关抗原,从而更精准高效地发挥抗肿瘤作用。本篇综述通过关注CAR-NK的靶点和相关免疫检查点,总结了CAR-NK在HCC治疗中面临的挑战及一些可能的解决方案,并讨论了提高CAR-NK疗效的潜在策略。

用于癌症免疫治疗的CAR-NK细胞递送技术

嵌合抗原受体(chimeric antigen receptor, CAR)工程化T (CAR-T)细胞在治疗血液系统恶性肿瘤方面取得显著成功,成为肿瘤免疫治疗的临床热点。然而,CAR-T细胞在对抗实体恶性肿瘤方面并未表现出太大的优势,因此,需要寻找新的效应细胞作为CAR修饰的候选细胞进行研究。最近,自然杀伤(natural killer, NK)细胞已成为CAR工程化的安全有效平台。CAR-NK细胞可被设计成能够靶向多种抗原的工程化细胞,以增强体内增殖力和持久性,增加对实体瘤的浸润,克服耐药性肿瘤微环境,最终实现有效的抗肿瘤反应。尽管NK细胞具有巨大的潜力,但已被证明难以改造,对细胞凋亡具有高敏感性且基因表达水平低。因此,对基因导入NK细胞的方法进行优化,会促进CAR-NK在研究和临床中的广泛应用。本文综述近年来NK细胞基因工程递送技术的改进,以及为增强NK细胞效应功能而实施的策略,包括NK细胞生物学特性、高效和安全的CAR构建体的设计、递送含CAR转基因载体的种类分析及提高转导效率方法的优化,以更好地靶向恶性肿瘤或抑制肿瘤的微环境,并进一步探讨CAR-NK相关研究中存在的问题和挑战,为恶性肿瘤相关疾病的治疗提供新的思路和方向。