结直肠癌细胞外泌体激活肝星状细胞为癌相关成纤维细胞

目的:探讨结直肠癌(CRC)细胞上清外泌体对肝星状细胞(HSC)细胞的影响。方法:通过超高速离心结合过滤法提取和纯化CRC细胞上清外泌体,然后以透射电电子显微镜(TEM)、纳米颗粒跟踪分析仪(NTA)和蛋白免疫印迹(WB)实验鉴定所提取的外泌体的形态、大小、粒径分布,以及外泌体表面标志蛋白HSP90和TSG101。再通过激光共聚焦显微镜(LSCM)观察荧光标记的外泌体被HSC细胞摄取的情况。以WB实验验证CRC细胞上清外泌体处理后的HSC中成纤维细胞活化蛋白(FAP)和α-平滑肌肌动蛋白(α-SMA)的表达水平。结果:TEM显示结直肠癌细胞外泌体呈\"茶托样\"杯型或类圆形囊泡样结构;NTA分析发现结直肠癌细胞外泌体直径峰值和大小分布范围分别为57 nm和30-150 nm;WB显示外泌体表面标志蛋白HSP90和TSG101均为阳性。LSCM观察发现Di O标记的外泌体(绿色),能够被Dil标记的HSC(红色)摄取。CRC细胞上清外泌体处理后的HSC中FAP和α-SMA表达水平较对照组显著升高。结论:HSC与CRC细胞上清外泌体共孵育后能够被激活成癌相关成纤维细胞。     

The key role of extracellular vesicles in the metastatic process

Extracellular vesicles (EVs), including exosomes, have a key role in the paracrine communication between organs and compartments. EVs shuttle virtually all types of biomolecules such as proteins, lipids, nucleic acids, metabolites and even pharmacological compounds. Their ability to transfer their biomolecular cargo into target cells enables EVs to play a key role in intercellular communication that can regulate cellular functions such as proliferation, apoptosis and migration. This has led to the emergence of EVs as a key player in tumor growth and metastasis through the formation of “tumor niches” in target organs. Recent data have also been shown that EVs may transform the microenvironment of primary tumors thus favoring the selection of cancer cells with a metastatic behavior. The release of EVs from resident non-malignant cells may contribute to the metastatic processes as well. However, cancer EVs may induce malignant transformation in resident mesenchymal stem cells, suggesting that the metastatic process is not exclusively due to circulating tumor cells. In this review, we outline and discuss evidence-based roles of EVs in actively regulating multiple steps of the metastatic process and how we can leverage EVs to impair metastasis.     

A short-term dietary supplementation with high doses of vitamin E increases NK cell cytolytic activity in advanced colorectal cancer patients

Cancer patients with advanced disease display signs of immune suppression, which constitute a major obstacle for effective immunotherapy. Both T cells and NK cells are affected by a multitude of mechanisms of which the generation of reactive oxygen species is of major importance. Therefore, we hypothesized that two weeks of high-dose treatment with the anti-oxidant vitamin E may enhance NK cell function in cancer patients by protecting from oxidative stress. Seven patients with colorectal cancer (Dukes stage C and D) received a daily dose of 750 mg of vitamin E during a period of two weeks and the function, phenotype and receptor expression of NK cells were analyzed. The short-term vitamin E treatment significantly improved NK cell cytolytic activity in six out of the seven patients analyzed. The increased NK cell activity in patients’ PBMC was not due to increased numbers of NK cells or an increase in the proportion of the CD56^dim NK cell subpopulation. Furthermore, neither an increased perforin expression nor an enhanced ability of NK cells to produce IFN-γ was observed as a result of vitamin E treatment. Finally, vitamin E treatment was associated with a minor, but consistent, induction of NKG2D expression in all patients analyzed. In conclusion, this pilot study demonstrates that vitamin E may boost NK cell function in patients with colorectal cancer. Further studies are warranted to explore the potential of vitamin E as an adjuvant for immunotherapy against cancer and to determine the underlying mechanism(s) behind vitamin E induced NK cell activation.     

胃癌的肿瘤微环境研究进展

肿瘤微环境是决定肿瘤细胞行为的主要影响因素,有别于正常细胞与其周围组织所形成的微环境,组织缺氧和酸中毒、间质高压形成、大量生长因子和蛋白水解酶的产生及免疫炎性反应等构成了肿瘤组织代谢环境的生物学特征,这种特性在肿瘤的发生、进展、转移中扮演重要的角色。胃癌早期症状不典型、转移迅速、死亡率高,是消化系统最常见的恶性肿瘤,目前,关于肿瘤微环境的研究尚处于起步阶段,对胃癌肿瘤微环境的研究有助于我们进一步认识胃癌发生发展的机制,并为临床诊断、治疗胃癌提供依据。因此,本文就近年来在胃癌肿瘤微环境方面的研究进展作一综述。     

具核梭杆菌促进结直肠癌发生发展机制研究进展

具核梭杆菌(Fusobacterium nucleatum)是一种人体共生菌,尤其富集于口腔,在特定情况下可导致机会感染.近年来,随着微生物群与健康或疾病相关性研究的深入,具核梭杆菌与结直肠癌(colorectal cancer,CRC)之间的关联性研究备受关注.大量临床研究表明,具核梭杆菌在CRC中更为富集,且进一步...     

抗血管生成治疗联合免疫检查点抑制剂在NSCLC中的研究进展

血管生成是非小细胞肺癌（NSCLC）生长、复发和转移的关键环节。抗血管生成治疗可以通过使肿瘤血管及微环境正常化,改善肿瘤血供和含氧量,增强放、化疗效果。也可以抑制肿瘤内毛细血管生长,使肿瘤细胞进入休眠状态,并诱导其凋亡。因此,靶向抗血管生成已成为NSCLC治疗研究的主要方向。贝伐珠单抗和雷莫芦单抗已被批准用于联合一线标准化疗治疗局部晚期或转移性NSCLC。然而,在这一治疗过程中,肿瘤会逐渐对抗血管生成药物产生耐药,这可能与肿瘤微环境（tumor microenvironment,TME）的改变有关。最近,免疫检查点抑制剂（immune checkpoint inhibitors,ICI）已经取得了相当大的成功,但是反应率仍然被认为不是最佳的。因此,为了提高疗效,各种组合疗法正在测试中。临床前数据表明促血管生成因子具有免疫抑制作用,为ICI和抗血管生成药物联合使用提供了合理的解释。并且有研究认为,抗血管生成治疗与肿瘤免疫治疗相联合可能是一种相互增益的治疗策略。     

EMT——联系免疫炎症反应与肿瘤发生发展的桥梁

恶性肿瘤严重威胁着人们的健康,肿瘤细胞侵袭和转移是恶性肿瘤患者死亡的重要原因。研究表明,肿瘤恶性转化的过程需要适宜的微环境,即肿瘤微环境,肿瘤细胞在肿瘤微环境中受到细胞因子、蛋白酶等多种因素的影响,发生免疫炎性反应、上皮间质转化（EMT）、刺激肿瘤血管形成等一系列病理生理改变,从而促进肿瘤的侵袭和转移。本文概述了机体免疫炎性反应、EMT和肿瘤微环境在肿瘤中的相互联系及其作用,以期为深入研究肿瘤发生发展的分子机制提供新的思路,并为肿瘤的分子靶向治疗提供理论依据。     

Vaccination of colorectal cancer patients with TroVax given alongside chemotherapy (5-fluorouracil, leukovorin and irinotecan) is safe and induces potent immune responses

Modified vaccinia Ankara (MVA) encoding the tumor antigen 5T4 (TroVax) has been evaluated in an open label phase II study in metastatic colorectal cancer patients. The primary objective was to assess the safety and immunogenicity of TroVax injected before, during and after treatment with 5-fluorouracil, leukovorin and irinotecan. TroVax was administered to 19 patients with metastatic colorectal cancer. Twelve patients had blood samples taken following each of the six injections and were considered to be evaluable for assessment of immunological responses. Both antibody and cellular responses specific for the tumor antigen 5T4 and the viral vector MVA were monitored throughout the study. Administration of TroVax alongside chemotherapy was safe and well tolerated with no SAEs attributed to the vaccine and no enhancement of chemo-related toxicity. Of the 12 patients who were evaluable for assessment of immune responses, ten mounted 5T4-specific antibody responses with titers ranging from 10 to > 5,000. IFNgamma ELISPOT responses specific for 5T4 were detected in 11 patients with frequencies exceeding one in 1,000 PBMCs in five patients. Eight patients presented with elevated circulating CEA concentrations, six of whom showed decreases in excess of 50% during chemotherapy and four had CEA levels which remained stable for > 1 month following completion of chemotherapy. Of the 19 intention to treat (ITT) patients, one had a CR, six had PRs and five had SD. Potent 5T4-specific cellular and/or humoral immune responses were induced in all 12 evaluable patients and were detectable in most patients during the period in which chemotherapy was administered. These data demonstrate that TroVax can be layered on top of chemotherapy regimens without any evidence of enhanced toxicity or reduced immunological or therapeutic efficacy.     

消化道微生物与胰腺癌相关性研究

胰腺癌是世界上最致命的恶性肿瘤之一,目前胰腺癌的病因尚未完全明确,是肿瘤研究领域的一个热点。近年来大量研究表明,胰腺癌的发生发展可能与消化道微生物群密切相关。近期研究发现,某些口腔、胃肠道和胰腺内的细菌、真菌和肝细胞病毒可能在胰腺癌发病机制中发挥潜在的病因作用。具体机制主要包括维持炎症、调节免疫系统、影响新陈代谢和改变肿瘤的微环境。在这篇综述中,探讨了消化道微生物与胰腺癌之间的联系,探讨微生物群在胰腺癌诊断和治疗中的潜在应用,并深入了解消化道微生物群在胰腺癌中的作用。     

Reduced expression of microenvironmental Th1 cytokines accompanies adenomas–carcinomas sequence of colorectum

Cytokines have been suggested to be key factors in modulating immune response against tumorigenesis in the microenvironment. Therefore, characterization of cytokine expression along the colorectal adenoma–carcinoma sequence may add important information for understanding the immune-related mechanisms of the development of colorectal carcinoma (CRC). In this study, biopsies from 32 patients with colorectal adenoma (CRA), 20 patients with CRC and 18 healthy controls were examined. Cytokine gene expressions of interleukin-4 (IL-4), IL-10, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma and its upstream inducers (IL-12A and IL-18) were measured at messenger RNA (mRNA) level with quantitative real-time PCR (Q-PCR). Cytokine expressing cells were characterized using immunohistochemistry (IHC). A distinct different cytokine profile between adenoma and CRC was observed: the Th1 cytokines (IFN-gamma, TNF-alpha, IL-12A and IL-18) were increased in local tissues of CRA and decreased in CRC. Consistent with the quantitative cytokine data, IHC examinations revealed slightly increased densities of Th1 cytokine-expressing cells in CRA and a remarkably decreased density of the Th1 cells in CRC. In CRA, the cytokine-expressing cells were highly polarized to the subepithelial stroma while the cells were evenly distributed through the stroma in CRC. In conclusion, distinct changes in the Th1 cytokine profile appear along the colorectal adenoma–carcinoma sequence. This may reflect a change in the host immune regulatory function in the adenoma–carcinoma sequence.     

Molecular lipidomics of exosomes released by PC-3 prostate cancer cells

The molecular lipid composition of exosomes is largely unknown. In this study, sophisticated shotgun and targeted molecular lipidomic assays were performed for in-depth analysis of the lipidomes of the metastatic prostate cancer cell line, PC-3, and their released exosomes. This study, based in the quantification of approximately 280 molecular lipid species, provides the most extensive lipid analysis of cells and exosomes to date. Interestingly, major differences were found in the lipid composition of exosomes compared to parent cells. Exosomes show a remarkable enrichment of distinct lipids, demonstrating an extraordinary discrimination of lipids sorted into these microvesicles. In particular, exosomes are highly enriched in glycosphingolipids, sphingomyelin, cholesterol, and phosphatidylserine (mol% of total lipids). Furthermore, lipid species, even of classes not enriched in exosomes, were selectively included in exosomes. Finally, it was found that there is an 8.4-fold enrichment of lipids per mg of protein in exosomes. The detailed lipid composition provided in this study may be useful to understand the mechanism of exosome formation, release and function. Several of the lipids enriched in exosomes could potentially be used as cancer biomarkers.