Influence of granulocyte-macrophage colonystimulating factor and tumor necrosis factor on anti-hepatoma activities of human dendritic cells

INTRODUCTIONDendritic cells (DCs) play a key regulatory role inantitumor immunity,especially in its immuneaccessory role via MHC-Ⅰ molecules.We haverecently reported that DCs were able to enhance thekilling activity of Lymphokine and PHA activatedkiller (LPAK) cells in vitro.In the presentstudy,we evaluated the effects of GM-CSF andTNF upon antitumor activities of freshly

Enhancing Antitumor by Immunization with Fusion of Dendritic Cells and Engineered Tumor Cell

A novel approach for a dentritic cells (DCs) based tumor vaccine was developed for the formation of hybrid engineered J558 after fusion with DCs. To make the hybrid tumor vaccine generate more efficient specific CTL cytotoxicity against wild type tumor cells, we genetically engineered tumor cells with mIL 12 gene prior to the cell fusion. mIL 12 was detected at 870±60 pg/(10 5 cells/ml) in the culture supernatants and the fusion ratio was about 30 % by the co focal microscopic analysis. Vaccination of mice with DCs fused with engineered J558 induced more efficient tumor specific CTL cytotoxicity against wild type tumor cells in vitro and with efficient antitumor immunity in vivo . These results suggest that this approach of using DCs fused with engineered tumor cells could be applied in clinical settings of DCs based cancer vaccines.

Dendritic cell-based vaccine for pancreatic cancer in Japan

"Vaccell" is a dendritic cell(DC)-based cancer vaccine which has been established in Japan. The DCs play central roles in deciding the direction of host immune reactions as well as antigen presentation. We have demonstrated that DCs treated with a streptococcal immune adjuvant OK-432, produce interleukin-12, induce Th1-dominant state, and elicit anti-tumor effects, more powerful than those treated with the known DCmaturating factors. We therefore decided to mature DCs by the OK-432 for making an effective DC vaccine, Vaccell. The 255 patients with inoperable pancreatic cancer who received standard chemotherapy combined with DC vaccines, were analyzed retrospectively. Survival time of the patients with positive delayed type hypersensitivity(DTH) skin reaction was significantly prolonged as compared with that of the patients with negative DTH. The findings strongly suggest that there may be "Responders" for the DC vaccine in advanced pancreatic cancer patients. We next conducted a smallscale prospective clinical study. In this trial, we pulsed HLA class Ⅱ-restricted WT1 peptide(WT1-Ⅱ) in addition to HLA class Ⅰ-restricted peptide(WT1-Ⅰ) into the DCs. Survival of the patients received WT1-Ⅰ and-Ⅱ pulsed DC vaccine was significantly extended as compared to that of the patients received DCs pulsed with WT1-Ⅰ or WT1-Ⅱ alone. Furthermore, WT1-specific DTH positive patients showed significantly improved the overall survival as well as progressionfree survival as compared to the DTH negative patients. The activation of antigen-specific immune responses by DC vaccine in combination with standard chemotherapy may be associated with a good clinical outcome in advanced pancreatic cancer. We are now planning a pivotal study of the Vaccell in appropriate protocols in Japan.

RNA vaccines for anti-tumor therapy

The immune system is able to recognize tumor antigens and this has been the basis for the development of cancer immunotherapies. The immune system can be instructed to recognize and attack tumor cells by means of vaccination strategies. One such strategy involves the delivery of tumor antigen as genetic material. Herewith we describe the use of RNA encoding tumor antigens for vaccination purposes in tumor settings. RNA has features that are interesting for vaccination. Upon transfection, the RNA has no possibility of integration into the genome, and the tumor translated proteins enter the intrinsic antigen processing pathway thus enabling presentation by MHC-I molecules. This can specifically activate cytotoxic CD8 T cells that can attack and kill tumor cells. RNA can be delivered as a naked molecule for vaccination purposes or can be used to transfect dendritic cells. The combination of RNA technology with dendritic cell vaccination provides a powerful tool for cancer immunotherapies.

Clinical and Immunological Effects in Patients with Advanced Non-Small Cell Lung-Cancer after Vaccination with Dendritic Cells Exposed to an Allogeneic Tumor Cell Lysate

Background: We evaluated the clinical and immunological effects of dendritic cell (DC) vaccination of patients with NSCLC. Autologous DCs were pulsed with a MAGE containing allogeneic melanoma cell lysate (MelCancerVac?, Dandrit Biotech,Copenhagen,Denmark). Imiquimod cream, proleukin and celecoxib were used as adjuvants to the vaccines. The objective of the study was to evaluate specific T cell response in vitro by IFNg EliSpot. Secondary objectives were overall survival, response and quality of life (QoL). Results: Twenty-two patients initiated the vaccination program consisting of ten vaccinations. Seven patients remained in stable disease (SD) three months after the first vaccination. After ten vaccinations (six months), four patients still showed SD and continued vaccinations on a monthly basis. These four patients received a total of 12, 16, 26 and 35 vaccinations, respectively. Five patients showed an unexpectedly prolonged survival. The treatment was well tolerated and only minor adverse events were reported. Quality of life did not change during the study period. In four of the seven patients with SD, vaccine-specific T cells were detected by IFNγ EliSpot assays, whereas only one patient with progressive disease (PD) showed vaccine-specific responses. Conclusion: This DC-based vaccine trial has indicated a correlation between vaccine-specific immunity and sustained SD. Furthermore, we observed an unexpectedly prolonged survival in some patients, which may indicate delayed effect of DC vaccination after completion of the treatment. A prospective randomized phase-IIb or -III is needed to further evaluate the use of MelCancerVac? vaccine treatment in patients with progressive NSCLC.

Advances in inducing adaptive immunity using cell-based cancer vaccines: clinical applications in pancreatic cancer

The incidence of pancreatic ductal adenocarcinoma(PDA) is on the rise, and the prognosis is extremely poor because PDA is highly aggressive and notoriously difficult to treat. Although gemcitabine- or 5-fluorouracil-based chemotherapy is typically offered as a standard of care, most patients do not survive longer than 1 year. Therefore, the development of alternative therapeutic approaches for patients with PDA is imperative. As PDA cells express numerous tumor-associated antigens that are suitable vaccine targets, one promising treatment approach is cancer vaccines. During the last few decades, cell-based cancer vaccines have offered encouraging results in preclinical studies. Cell-based cancer vaccines are mainly generated by presenting whole tumor cells or dendritic cells to cells of the immune system. In particular, several clinical trials have explored cell-based cancer vaccines as a promising therapeutic approach for patients with PDA. Moreover, chemotherapy and cancer vaccines can synergize to result in increased efficacies in patients with PDA. In this review, we will discuss both the effect of cell-based cancer vaccines and advances in terms of future strategies of cancer vaccines for the treatment of PDA patients.

GENETICALLY MODIFIED DENDRITIC CELLS INDUCED SPECIFIC CYTOTOXITY AGAINST HUMAN HCC CELLS IN VITRO

Objective: to transduce the tumor associated antigen gene MAGE-1 and/or IL-12 gene into dendritic cells (DC) and to observe the in vitro cytotoxic effect induced by the genetically modified DC against the human hepatocellular carcinoma (HCC) cell line SMMC7721. Methods: the MAGE-1 gene was inserted into the retrovirus vector LXSN to construct the recombinant retrovirus LMSN. The monocyte-derived DCs were transfected at appropriate differentiation stage by LMSN and/or a recombinant adenovirus AdmiL-12, which containing murine IL-12 gene. The control groups included retrovirus LXSN transfected, adenovirus AdBGFP transfected and non-transfected DCs. The MAGE-1 gene expression was identified by western blot and the mIL-12 p70 secretion was detected by ELISA assay. The in vitro cytotoxicities against SMMC7721 induced by genetically modified and control groups of DC were tested by MTT assay. Results: The MAGE-1 expression was detected by a monoclonal antibody in DCs tranfected with LMSN but not in control groups. At 16 h, 24 h and 48 h after transfection with AdmIL-12, the concentration of the mIL-12 p70 in the culture medium was 580pg/106 cells, 960pg/106 cells and 1100pg/106 cells respectively. The mIL-12 p70 secretions were not detected in other groups. The lytic activity (as judged by % lysis) induced by each groups of DC was 94.2±5.2% (LMSN and AdmIL-12 cotransfected group), 78.9±3.6% (LMSN transfected groups), 52.6±9.7% (AdmIL-12 transfected group), 34.7±4.3% (LXSN transfected group), 36.3±3.8% (AdBGFP transfected group) and 3.9±2.0% (non-transfected group) respectively. Except for LXSN transfected and AdBGFP transfected group, the difference of the lytic activities between other groups were statistically significant (P<0.05). Conclusion: The MAGE-1 gene modified DCs can induce relatively specific cytotoxicty against SMMC7721 in vitro and thus suggested that those genetically engineered DCs have the potential to serve as novel vaccine for HCC. Transduction of exogenous IL-12 gene into DCs may further enhance DCs’ activity and the effectiveness of the above DC vaccine.

Melanoma Immunotherapy: Overcoming Obstacles to Augment Anti-Tumor Immune Responses

Melanoma is the most aggressive form of skin cancer and accounts for the vast majority of skin cancer-related deaths. Its ability to metastasize quickly, often before diagnosis, makes this cancer difficult to treat with traditional therapies. The identification of anti-melanoma immune responses in patients and the discovery of tumor antigens targeted by these immune responses have paved the way for immunotherapy as a novel approach to treating this cancer. In this review, the major immunotherapies targeting these melanoma tumor antigens are discussed. The advantages and limitations of peptide-, protein-, and gene-based vaccination maneuvers and adoptive cell transfer therapies are emphasized. Recent insights into melanoma immune evasion strategies are also highlighted, with particular focus on how our increasing knowledge of tumor/immune cell interactions is driving the development of novel immunotherapeutic strategies for the treatment of melanoma.

Therapeutic tumor vaccines-a rising star to benefit cancer patients

Malignant tumors are still a worldwide threat to human health.Tumor treatment strategies are constantly evolving,and the advent of tumor immunotherapy has brought up hope to many types of tumors,especially for those that are refractory to conventional therapies including surgery,radiotherapy,and chemotherapy.Tumor vaccines can initiate or amplify an anti-tumor immune response in tumor patients through active immunization,and therefore occupy an important position in tumor immunotherapy.The main types of tumor vaccines include tumor cell vaccines,dendritic cell vaccines,polypeptide vaccines and nucleic acid vaccines.Due to factors such as poor antigen selection and suppressive tumor microenvironment,earliest tumor vaccines on clinical trials failed to achieve satisfactory clinical effects.However,with the development of second-generation genome sequencing technologies and bioinformatics tools,it is possible to predict neoantigens generated by tumor-specific mutations and therefore prepare personalized vaccines.This article summarizes the global efforts in developing tumor vaccines and highlights several representative tumor vaccines in each category.

新抗原脉冲树突状细胞疫苗在肿瘤免疫治疗中的作用

新抗原脉冲树突状细胞疫苗(Neo-DCVac)是一种新型肿瘤免疫治疗手段。新抗原是指肿瘤细胞突变产生的具有较强免疫原性和肿瘤特异性的肽段。Neo-DCVac是基于新抗原被树突状细胞摄取、加工后递呈并激活T细胞引发机体免疫反应,从而发挥抗肿瘤作用。在高通量测序基础上发展而来的个体化Neo-DCVac有望成为肿瘤精准免疫治疗的新方向。本文从个体化Neo-DCVac构建、在实体瘤中联合治疗的临床应用、适宜接种人群和目前存在的局限性等方面进行综述,旨在为肿瘤免疫治疗的相关研究提供参考。

MHSP65-TCL疫苗对不同病理类型三阴性乳腺癌治疗效果的差异

目的评估及比较改良后的结核分枝杆菌热休克蛋白65-肿瘤细胞裂解物(MHSP65-TCL)疫苗对不同类型三阴性乳腺癌的疗效和差异。方法首先,生物信息学分析不同病理类型三阴性乳腺癌肿瘤微环境中免疫细胞浸润活化情况;其次,分析三阴性乳腺癌细胞中RACK1、Bcl-2、CTNNBL1等细胞活化因子,及细胞凋亡诱导因子PDL1、HMGB1、Fas-L在三阴性乳腺细胞中的丰度及其影响免疫细胞活化的信号通路。进而,在制备MHSP65-TCL去除TCL中的PDL1或增加TCL中Bcl-2,再通过体内外抗肿瘤实验,检测、比较两种方法治疗不同类型三阴性乳腺癌效果的差异。结果蛋白表达丰度的检测,MDA-MB-453细胞中HMGB1的表达量是最高的,但Bcl-2表达最低,结合各类型三阴性乳腺癌淋巴浸润,体外杀伤实验以及体内动物实验,3种不同类型的三阴性乳腺癌细胞尤其是LAR型细胞系MDA-MB-453,主要依赖HMGB1抑制免疫细胞。从TCL中去除HMGB1可以更为有效地提高MHSP65-TCL的抗肿瘤效果。结论阐明MHSP65-TCL疫苗对各类型三阴性乳腺癌疗效差异及机制,并建立起一种三阴性乳腺癌治疗的新方法。

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.

Personalized cancer vaccines from bacteria-derived outer membrane vesicles with antibody-mediated persistent uptake by dendritic cells

Nanocarriers with intrinsic immune adjuvant properties can activate the innate immune system while delivering tumor antigen,thus efficiently facilitating antitumor adaptive immunity.Bacteria-derived outer membrane vesicles(OMVs)are an excellent candidate due to their abundance of pathogen associated molecular patterns.However,during the uptake of OMVs by dendritic cells(DCs),the interaction between lipopolysaccharide and toll-like receptor 4 induces rapid DC maturation and uptake blockage,a phenomenon we refer to as“maturation-induced uptake obstruction"(MUO).Herein we decorated OMV with the DC-targeting aDEC205 antibody(OMV-DEC),which endowed the nanovaccine with an uptake mechanism termed as 4<not restricted to maturation via antibody modifying”(Normandy),thereby overcoming the MUO phenomenon.We also proved the applicability of this nanovaccine in identifying the human tumor neoantigens through rapid antigen display.In summary,this engineered OMV represents a powerful nanocarrier for personalized cancer vaccines,and this antibody modification strategy provides a reference to remodel the DC uptake pattern in nanocarrier design.

铝纳米粉末活化树突状细胞的作用

采用电爆炸法制备金属铝纳米粉末(ALEX),验证了其免疫增强效应及肿瘤预防效果.首先,利用铝金属丝电爆炸法,并应用羧基端基聚合物配体反应的方法合成了分散性良好的ALEX.利用静电物理吸附将抗原卵清蛋白(OVA)、抗原多肽(Peptide)接枝于ALEX表面,傅里叶变换红外光谱检测证明抗原与ALEX成功覆合.其次,验证了ALEX增强特异性免疫反应的效果.通过体外实验证明,ALEX可提高树突状细胞(DCs)的抗原提呈效果;同时,对免疫后小鼠血清抗体进行了定量检测,结果表明ALEX可显著提高小鼠体内抗原特异性抗体的水平.最后,利用小鼠黑色素瘤模型,验证了含有ALEX的肿瘤疫苗能够有效预防肿瘤的发生.

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。

治疗黑色素瘤的DC疫苗研究新进展

黑色素瘤是最具侵袭性的皮肤恶性肿瘤,易发生早期转移和治疗后复发。治疗性肿瘤疫苗是新兴的免疫疗法,具有毒性低以及可抑制肿瘤转移的特点。目前已有多个针对黑色素瘤治疗性疫苗的研究,其中黑色素瘤治疗性树突状细胞(DC)疫苗引起了广泛关注。虽然肿瘤治疗性DC疫苗在黑色素瘤中的疗效已被多项研究证实,但该类疫苗存在免疫效应不足、单独使用疗效不佳等问题,仍具有较大的改进空间。本文对黑色素瘤的治疗性DC疫苗的研究现状进行了综述,并对肿瘤治疗性DC肿瘤的研究重点及优化策略进行展望。

Total tumor RNA pulsed dendritic cells plus adoptive transfer of ex-vivo enriched autologous T-lymphocytes in the treatment of children with primary brain tumors

The therapeutic approach of adoptive lymphocyte transfer (ALT) using lymphocytes primed and expanded ex-vivo by exposure to total tumor RNA (ttRNA) containing dendritic cells (DCs) and administered after lymphodepletive host conditioning in patients with refractory melanoma with brain metastases has shown excellent objective responses indicating that the central nervous system (CNS) is not an immune privileged site and further paved the way for utilization of a similar approach in other cancers. We have shown that the use of ALT + ttRNA DCs following either myeloablative or non-myeloablative host conditioning is feasible and safe and appears to prolong survival in a proportion of children with recurrent medulloblastoma who had failed standard cytotoxic therapy. Further refinements in this promising approach are needed to improve outcomes and extend this treatment to a broad range of CNS malignancies.

卵巢癌细胞和脐血树突状细胞融合瘤苗抗肿瘤免疫效应的初步研究

目的:将脐血来源的树突状细胞(DC)与人卵巢癌细胞株SKOV3细胞相融合,获得SKOV3/DC融合细胞,分析其生物学特性及体外诱导抗卵巢癌肿瘤免疫的能力。方法:1)将用pKH26红色荧光染料标记脐血来源的DC后,聚乙二醇法(PEG)融合DC与人卵巢癌细胞株SKOV3细胞,流式细胞仪分选融合细胞。2)应用细胞培养技术、流式细胞术及光学显微镜检测SKOV3/DC的生长特性和形态学特征;四甲基偶氮唑蓝(MTT)法观察融合细胞体外刺激混合淋巴细胞反应的能力及诱导特异性肿瘤免疫的能力。结果:1)DC和SKOV3按10:1比例融合,融合率约为8.5%。融合细胞可在体外缓慢增殖,CA125抗原及CD1a、CD80、CD86、HLA-DR、MHC-I分子表达阳性。2) SKOV3/DC在体外能有效的激发混合淋巴细胞增殖反应,可明显激活细胞毒性T淋巴细胞(CTL),对卵巢癌细胞株SKOV3有特异性杀伤效应。结论:利用PEG法制备的SKOV3/DC融合细胞兼具两种亲本细胞的部分特性,在体外能够诱导特异性抗肿瘤免疫。本研究将SKOV3/DC作为肿瘤疫苗,为其在卵巢癌主动免疫治疗研究中的进一步应用打下了基础。

枸杞多糖增强人树突状细胞抗肿瘤的机制

目的观察枸杞多糖对树突状细胞抗肿瘤的增强作用。方法分离人外周血单核细胞,体外培养其成为未成熟树突状细胞和成熟树突状细胞。用冻融法制备肝癌细胞的全抗原并致敏未成熟树突状细胞;通过混合淋巴细胞实验,获取成熟树突状细胞激活的特异性效应T细胞。用MTT法测定效应T细胞对肝癌细胞的杀伤率。观察枸杞多糖在树突状细胞的成熟及T细胞的激活、增殖和杀瘤过程中的作用。结果枸杞多糖能促进树突状细胞的成熟,转染了人肝癌细胞的全抗原的mDC可特异地激活T细胞为效应T细胞。效应T细胞可特异性地杀伤人肝癌细胞,而对不相关的MG-63细胞无特异性的杀伤作用。结论枸杞多糖能促进树突状细胞成熟和增强效应T细胞的增殖和杀伤肿瘤的活性。

树突状细胞体外诱导抗肿瘤免疫通过诱导肿瘤细胞凋亡抑制裸鼠移植瘤生长

研究树突状细胞（ＤＣ）体外诱导的细胞免疫抑制裸鼠移植瘤生长作用及其机理。方法：联合应用粒／巨噬细胞集落刺激因子ＫＭ－ＣＳＦ）及白介素－４（ＩＬ－４）直接从肝癌患者外周血中培养出ＤＣ，以人肝癌细胞系ＨｅｐＧ２肿瘤细胞的肿瘤抗原粗提物刺激ＤＣ，ＤＣ激活同源的Ｔ淋巴细胞，建立裸鼠人肝癌细胞系ＨｅｐＧ２移植瘤模型，以被激活的Ｔ淋巴细胞治疗裸鼠ＨｅｐＧ２移植瘤并观察治疗效果，检测移植瘤标本肿瘤细胞凋亡情况。结果：ＤＣ诱导的Ｔ细胞免疫能够诱导裸鼠人肝癌细胞系ＨｅｐＧ２移植瘤肿瘤细胞大量凋亡从而抑制裸鼠ＨｅｐＧ２移植瘤生长。结论：经肿瘤抗原激活的ＤＣ作为一新概念上的抗肿瘤疫苗有可能在肿瘤的治疗中发挥重要作用。