组织蛋白酶及其抑制剂研究进展

组织蛋白酶是半胱氨酸蛋白酶家族的主要成员,在生物界已发现20余种,人体中主要存在11种,它们与人类肿瘤、骨质疏松、关节炎等多种重大疾病密切相关,是近年来备受关注的一类靶标蛋白酶。自从20世纪90年代以来,多种组织蛋白酶的晶体结构陆续明确,有关其研究进展较快。本文以人类组织蛋白酶为重点,主要介绍近15年来组织蛋白酶结构、功能和抑制剂研究方面的一些重要进展。     

神经节苷脂GD3与肿瘤的血管生成作用(英文)

 血管生成作用 (angiogenesis)是实体瘤 (solidtumor)生长和扩散的必要条件 .实体瘤的微血管密度与肿瘤的恶性程度成正相关 ,而且也与病人的预后密切相关 .因此 ,对抗血管生成作用是一种很有吸引力的肿瘤疗法 .神经节苷脂GD3在多种类型的肿瘤中超常表达 .一般认为 ,神经节苷脂GD3有增强肿瘤本身及邻近组织中的血管生成作用 ,从而促进肿瘤的演进和转移 .最近的研究工作为这一假设提供了有力的实验证据 .应用GD3合酶的反意DNA转染肿瘤细胞从而抑制细胞中的GD3合酶的表达 ,极大地降低了细胞的内源GD3含量 .进一步的研究证明 ,抑制肿瘤细胞的GD3合成明显地降低了该肿瘤细胞的血管内皮生长因子 (VEGF)的水平 ,并使血管生成作用降至最小限度 .这些实验说明GD3在肿瘤的血管生成中具有重要的作用 .此外 ,GD3作为肿瘤的一种相关抗原 ,它与血管生成因子的协同效应将在未来的联合基因疗法中起到重要的作用     

糖基磷脂酰肌醇锚定蛋白质与肿瘤血管生成的关系

肿瘤血管生成是一个非常复杂的过程,涉及到多种因子的调节。目前,已发现多种糖基磷脂酰肌醇锚定蛋白质与肿瘤血管生成密切相关。尿激酶型纤溶酶原激活剂受体(urokinase plasminogen activator receptor,uPAR/CD87)、CD55、基质金属蛋白酶、T-钙黏着蛋白、RECK、Eph家族受体作用蛋白A(Eph family receptor interacting protein A,ephrin A)等均能调节肿瘤血管生成过程。本文对糖基磷脂酰肌醇锚定的调节因子如何影响肿瘤血管生成,以及它们作为肿瘤治疗的主要靶标研究进行综述,为肿瘤治疗的抗血管生成新靶标的设计提供信息。     

肿瘤血管靶向药物的研究进展

肿瘤血管在实体瘤的发生发展中具有重要的作用,靶向肿瘤血管的新药研发已成为一个热点领域.抗肿瘤血管的治疗策略分为肿瘤新生血管生成抑制剂（tumor angiogenesis inhibitor,TAI）和肿瘤血管靶向药物（vascular targeting agents,VTAs）两方面的研究.肿瘤新生血管生成抑制剂旨在抑制肿瘤新生血管生成的过程,而肿瘤血管靶向药物则是通过快速而有选择性地破坏肿瘤血管功能,使肿瘤血供受阻,导致肿瘤坏死.VTA类药物分为两类：一是小分子抑制剂（small molecule agents）,利用肿瘤血管和正常组织血管存在的差别选择性地破坏肿瘤血管;另一种是生物制剂（biological agents）,借助能够特异结合肿瘤血管的配体将毒素、凝血诱导剂、凋亡诱导分子等运送到肿瘤血管,引起血管阻塞使肿瘤坏死.     

肿瘤的分子治疗新进展

肿瘤的发生、发展是一个多步骤、多基因参与的、复杂的系统性过程.分子治疗作为21世纪最有希望根治人类肿瘤的技术,其治疗技术的关键在于靶分子的选择,寻找合适的靶分子一直是分子治疗肿瘤的重要方向.针对近年来肿瘤治疗研究中发现的端粒酶靶标、抗血管生成基因靶标、apoptin、survivin、stathmin、autophagy、PUMA、转铁蛋白受体靶标和相应的治疗策略作一综述.     

内皮细胞抑制素的研究进展

内皮细胞抑制素是一种新发现的特异的血管内皮细胞增殖抑制剂,它可以有效地抑制内皮细胞生长,对肿瘤血管形成具有强烈的抑制作用,在抗实体瘤方面有显著的效果。本文就它的发现、结构、生物学活性、作用机理及研究进展进行综述。     

Cystatin B与肿瘤关系

Cystatin B作为半胱氨酸蛋白酶超家族中的一员,主要抑制组织蛋白酶L.许多研究表明cystatin B可能参与多种肿瘤如头颈部鳞癌、乳腺癌、食管癌、肝细胞癌、肺癌等的生长、侵袭和转移过程.其作用机制仍有待进一步阐明.Cystatin B要作为临床诊断和预后的指标而得到应用仍需更深入的研究.     

CAR-T 对肿瘤的特异性治疗研究进展

嵌合抗原受体T细胞免疫疗法(CAR-T疗法)是一种治疗肿瘤的新免疫疗法,通过向患者自身T细胞中导入已被修饰的CAR基因,使T细胞表达结合肿瘤表面抗原的特异性受体来实现对肿瘤的精准治疗.目前已发展到第四代.该免疫疗法在血液瘤和实体瘤治疗中都有一定疗效,同时也存在一些待解决难题.本文就近年来CAR-T在血液瘤和实体瘤中的研究治疗进展及存在的问题进行综述.     

MicroRNA与肿瘤血管生成

microRNA（miRNA）是近年来发现的一类长度约为22个核苷酸的非编码小分子RNA.它主要通过与靶标基因3′UTR的完全或不完全配对,降解靶标基因mRNA或抑制其翻译,从而参与多种生命活动.血管生成在肿瘤的发生、发展过程中起着重要的作用.实验证据表明,miRNAs可通过调控其靶标基因参与的信号通路,影响肿瘤血管的生成.本文主要介绍近年来miRNAs与血管生成相关性研究的进展.     

肿瘤血管生成抑制因子在实体瘤治疗中的应用

肿瘤的治疗是近年来广大科研及医务工作者共同关注的问题。本文通过对血管生成与肿瘤生长的关系、血管生成因子和血管生成抑制因子功能的阐述,说明了血管生成抑制因子在肿瘤发生过程中的可能作用,从而为实体瘤的抗血管生成疗法提供了理论依据。     

A Legumain-based minigene vaccine targets the tumor stroma and suppresses breast cancer growth and angiogenesis

Tumor associated macrophages (TAMs) are well known to play a very important role in tumor angiogenesis and metastasis. The suppression of TAMs in the tumor-microenvironment (TME) provides a novel strategy to inhibit tumor growth and dissemination by remodeling the tumor’s stroma. Here, we tested our hypothesis that suppression of TAMs can be achieved in syngeneic BALB/c mice with oral minigene vaccines against murine MHC class I antigen epitopes of Legumain, an asparaginyl endopeptidase and a member of the C13 family of cystine proteases which is overexpressed on TAMs in the tumor stroma. Vaccine vectors were constructed and transformed into attenuated Salmonella typhimurium (Dam ⁻ , AroA ⁻ ) for oral delivery. Groups of mice received either the expression vectors encoding the Legumain H-2D or 2K epitopes or the control empty vector by gavage. The efficacy of the minigene vaccines was determined by their ability to protect mice from lethal tumor cell challenges, the induction of a specific CTL response as well as IFN-γ release, and inhibition of tumor angiogenesis. We demonstrated that the Legumain minigene vaccine provided effective protection against tumor cell challenge by inducing a specific CD8⁺ T-cell response against Legumain⁺ TAMs in our breast tumor model. The protection, induced by this T-cell response, mediated by the Legumain Kd minigene, is also responsible for lysing D2F2 breast carcinoma cells in syngeneic BALB/c mice and for suppressing tumor angiogenesis. Importantly, in a prophylactic setting, the minigene vaccine proved to be of similar anti-tumor efficacy as a vaccine encoding the entire Legumain gene. Together, our findings establish proof of concept that a Legumain minigene vaccine provides a more flexible alternative to the whole gene vaccine, which may facilitate the future design and clinical applications of such a vaccine for cancer prevention.     

Computational challenges of tumor spheroid modeling

The speed and the versatility of today's computers open up new opportunities to simulate complex biological systems. Here we review a computational approach recently proposed by us to model large tumor cell populations and spheroids, and we put forward general considerations that apply to any fine-grained numerical model of tumors. We discuss ways to bypass computational limitations and discuss our incremental approach, where each step is validated by experimental observations on a quantitative basis. We present a few results on the growth of tumor cells in closed and open environments and of tumor spheroids. This study suggests new ways to explore the initial growth phase of solid tumors and to optimize antitumor treatments.     

Analysis of surface membrane antigens, cytoskeletal proteins and N-myc oncogene in pediatric solid malignant tumors, their diagnostic usefulness and relevant problems]

Neuroblastoma (NB), primitive neuroectodermal tumor (PNET), Ewing's sarcoma and rhabdomyosarcoma (RMS) are solid malignant tumors in childhood. Microscopically these tumors are grouped as small-round-cell tumors, and a different diagnosis is sometimes difficult. Cell surface membrane antigen, cytoskeletal protein and N-myc amplification and over-expression were analyzed in these cell lines and tumor tissues for the accurate diagnosis. NB and PNET could be distinguished from Ewing's sarcoma and RMS by the panel of monoclonal antibodies against cell surface membrane antigens. The cytoskeletal protein analysis is useful for the diagnosis of RMS and leiomyosarcoma. Alpha-smooth muscle actin and/or desmin were demonstrated in the S-type (epithelial-like) cells in 3 NB cell lines, suggesting the differentiation pathway of NB into smooth muscle cells. N-myc amplification and over-expression were observed in NB cell lines as well as one RMS cell line. The occurrence of N-myc amplification and over-expression in the RMS cell line cautions us against using N-myc as a distinguishable marker for NB.     

pHLIP and acidity as a universal biomarker for cancer

Of great importance to clinical cancer diagnosis is the use of organic biomarkers. The detection of RNA, DNA, and protein antigen are all established methods for identifying specific cancer types and instrumental in promoting greater survivorship of the patient. Despite many decades of intense cancer research, we have yet to identify a "universal" protein or nucleic acid that allows us to diagnose more than a small subset of cancers at a time. In this review, we examine the use of localized cellular acidity as a universal marker for solid tumors, outlining some successes with a small peptide we call pHLIP, a pH-sensitive biosensor that allows us to label tumor tissue in live mice.     

Nitric oxide complexes in the interaction between primary and secondary tumor of L5178Y lymphoma.

Heme and non-heme Fe-NO complexes were observed in regard to the growth of primary and secondary solid tumors and ascites of murine L5178Y lymphoma. The complexes were detected by electron paramagnetic resonance spectroscopy at liquid nitrogen temperature. Primary solid tumors and secondary solid tumors or ascites were inoculated on the same day, or with a delay. The primary tumor inhibited growth of the secondary solid tumor only if the latter was inoculated with a delay, which did not correlate with the change of the types, nor with the increase in the level of Fe-NO complexes detected in the tissue, suggesting a "non-immunological" character of this inhibition. In some animals with solid tumors, spontaneous ascites developed. This process resulted in a marked decrease in the level of Fe-NO complexes in the solid tumor tissue. The primary solid tumor, however, did not influence the growth of secondary ascites, but intensified NO generation in the ascites of animals with partial removal of ascitic fluid. This experimental group survived 2.2 days longer than the control group without primary solid tumor. Our research revealed that the presence of Fe-NO complexes in the interaction between primary and secondary tumor strongly depends on the form of the tumor: solid or ascitic, and that murine L5178Y lymphoma may serve as a convenient model for the research on "concomitant immunity" against in vivo growing tumors. This is the first EPR study on "concomitant immunity" in regard to tumor-tumor and tumor-ascites interactions in vivo.     

Use of interphase cytogenetics in demonstrating specific chromosomal aberrations in solid tumors--new insights in the pathogenesis of malignant melanoma and head and neck squamous cell carcinoma

The detection of structural and numerical chromosomal aberrations is an important part of the characterization of tumors and genetic diseases. The direct demonstration of DNA sequences in interphase nuclei and metaphases by fluorescence in situ hybridization (FISH) has been termed interphase cytogenetics. It has been proven as a powerful technique to detect specific aberrations in a wide variety of cell types, including paraffin-embedded tissue. Nowadays a standard method in leukemia and lymphoma, interphase cytogenetics contributes mainly to the diagnosis in these tumors and helps to classify soft tissue tumors. Therefore FISH is mandatory for the choice of therapy in these tumors. In contrast to the aforementioned, up to now, the value of FISH in solid tumors is mostly limited to pure research and contributes in this way to our understanding of tumor biology. But with the use of paraffin-embedded tissue and the first results obtained, it seems very likely that a direct correlation between histological classification and cytogenetic characteristics of solid tumors can be achieved in the near future. This information might not only provide insights into tumor biology, but could also contribute to a different tumor classification, a sort of risk estimation, where we might predict the possible biological behavior of solid tumors. This could greatly influence further therapeutic decisions thus establishing the FISH technique as an indisputable part in the diagnosis of solid tumors.     

Legumain: a biomarker for diagnosis and prognosis of human ovarian cancer

Legumain is a member of the asparaginyl endopeptidase family that is over‐expressed in response to hypoxic stress on mammary adenocarcinoma, colorectal cancer, proliferating endothelial cells, and tumor‐associated macrophages (TAMs). Here, we demonstrate that elevated expression of legumain in ovarian cancer by a proteomic approach using isobaric tags for relative and absolute quantification (iTRAQ) followed by liquid chromatography–mass spectrometry (LC–MS/MS). To investigate the relationship between legumain expression and ovarian cancer development, we tested legumain expression in malignant human ovarian tumors (n = 60), borderline ovarian tumors (n = 20), benign ovarian tumors (n = 20), and normal ovary samples (n = 20) using immunohistochemical assay (IHC). A correlation between legumain expression, and clinocopathologic and biological variables was also established. Importantly, increased legumain expression was validated by real‐time PCR and Western blots, correlated positively with an increased malignancy of ovarian tumors (P < 0.01). In fact, patients with strong legumain expression had a worse prognosis (P = 0.03). In addition, results of in vitro experiments revealed that over‐expression of legumain correlates with increased cell migration and invasion of ovarian cancer cells. Although legumain's functional role and clinical utility remain to be established, our results indicated that a sensitive assay for early expression of legumain may serve as both a potential biomarker and a molecular target for treatment of ovarian cancer. J. Cell. Biochem. 113: 2679–2686, 2012. © 2012 Wiley Periodicals, Inc.     

P3 SAR exploration of biphenyl carbamate based Legumain inhibitors

This Letter describes the further development and SAR exploration of a novel series of Legumain inhibitors. Based upon a previously identified Legumain inhibitor from our group, we explored the SAR of the carbamate phenyl ring system to probe the P3 pocket of the enzyme. This led to the identification of a sub-nanomolar inhibitor of Legumain.     

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.