DAB389EGF fusion protein therapy of refractory glioblastoma multiforme

Primary brain tumors including anaplastic astrocytomas and glioblastoma multiforme are difficult to treat because of their locally invasive nature and chemoradioresistance. Novel therapies are needed. One class of therapeutics is fusion proteins consisting of peptide toxins fused to brain tumor selective ligands. DAB389EGF is a fusion protein composed of the catalytic and translocation domains of diphtheria toxin fused via a His-Ala linker to human epidermal growth factor (EGF). DAB389EGF is selectively toxic to EGF receptor (EGFR) overexpressing cells. Close to half of all high-grade primary brain tumors have EGFR gene amplification and EGFR overexpression. With the use of convection-enhanced delivery (CED), DAB389EGF may be delivered locally at high concentrations to the brain tumor. CED would avoid many of the pharmacologic and toxicologic barriers which have limited effective use of this agent including rapid clearance from the circulation, high anti-diphtheria toxin antibody titers in the blood and toxicities to the liver and kidney. Both cell lines and animal models are available to assess the potential of this agent for brain tumor therapy. Since significant amounts of clinical grade DAB389EGF are available, some careful additional preclinical efficacy work should lead to testing of this agent in patients within the next few years.     

Dysregulation of protein kinase C activity in chemoresistant metastatic breast cancer cells

This study was performed to evaluate the role of protein kinase C (PKC) activity in the development of chemoresistance in clinical breast cancer cells. To simulate the clinical situation, native tumor cells derived from 10 patients with advanced breast cancer were brought into short-term cultures, and treated with anthracyclines (doxorubicin, mitoxantrone), paclitaxel and combinations, respectively. After 3 days of incubation, we determined total PKC activity relative to each control incubated with blank medium. Furthermore, we determined the chemoresistance against these drugs from each cell population separately. Relative PKC activity ranged from 14 to 249%; 64% (37 of 58) of the breast cancer cell suspensions were considered chemoresistant. There was a non-significant trend to a higher relative PKC activity in resistant cells compared to non-resistant cells (p=0.058), regardless of the antineoplastic agent investigated. The individual variability in both PKC activity and chemoresistance pattern revealed that dysregulated PKC activity mediates resistance to antineoplastics. In order to achieve clinical value, evaluation of more data concerning the PKC signal-transduction pathway is necessary. New protocols of cancer treatment will require this information in order to be successful.     

Antiangiogenic therapy in hematologic malignancies

Angiogenesis is defined as the formation of new capillaries from prexisting blood vessels and plays an important role in the progression of solid tumors and hematologic malignancies. Markers of angiogenesis correlate with clinical characteristics in leukemia and non-Hodgkin's-lymphoma, serving as predictors of poor prognosis. Antiangiogenic effects of chemotherapeutics as well as of novel drugs such as farnesyltransferase inhibitors and tyrosine kinase inhibitors such as Gleevec might contribute to their therapeutic potential. Thalidomide which has antiangiogenic effects and direct cytotoxic effects was found to be effective in multiple myeloma and is considered as an established treatment modality for patients with refractory or relapsed multiple myeloma. Thalidomide has a significant therapeutic effect in myelodysplastic syndrome (MDS) by improving cytopenia and achieving independence of transfusion therapy in a subset of patients. Preliminary data indicate activity of specific VEGF receptor tyrosine kinase (RTK) inhibitors in multiple myeloma (MM) and acute myeloid leukemia (AML). The positive correlation between increased levels of angiogenic cytokines and clinical response to VEGF-RTK inhibitors and thalidomide indicates the relevance of detecting angiogenesis markers to identify best candidate patients for specific approaches. Including antiangiogenic drugs into treatment protocols for hematologic malignancies is an important task for future clinical studies.     

IL-12-Based therapy of malignancies

Interleukin-12 (IL-12) is an important molecule that triggers the activation of natural killer (NK) cells and T-cells, the development of T helper type 1 (Th1) cells and the expression of antiangiogenic genes. Novel methods for IL-12 delivery include cell-based ex vivo gene therapy, viral vector-based gene therapy and DNA plasmid-based nonviral gene therapy. IL-12 electroporation gene therapy may hold some promise for tumors accessible by electrode, such as head and neck cancer, breast cancer, prostate cancer and melanoma. Codelivery of other therapeutic genes with IL-12 may enhance the therapeutic effect and reduce the level of IL-12 required for efficacy. All three approaches to IL-12 gene therapy are under clinical investigation. The preliminary results indicate that IL-12 gene therapy is safe and is not associated with any major clinical toxicity. (c) 2001 Prous Science. All rights reserved.     

CpG oligodeoxynucleotide-based therapy of lymphoid malignancies

Preclinical and early clinical trials indicate synthetic oligodeoxynucleotides containing unmethylated CG dinucleotides (CpG ODN) have potent immunostimulatory effects. CpG ODN are being explored as immune adjuvants in vaccination strategies and as potential treatments for a wide variety of disorders including cancer and asthma. Therapeutic approaches designed to take advantage of this potent class of agents are based largely on the ability of CpG ODN to activate professional antigen presenting cells (APCs) that express the target receptor — Toll-Like Receptor 9 (TLR9). B-cell malignancies are unique in that the malignant cells themselves express TLR9. CpG ODN can have a direct effect on the malignant B cells and lead to activation induced cell death. CpG ODN also alter the phenotype of target malignant B cells as indicated by upregulation of MHC, immunostimulatory molecules, and antigens that serve as targets for other approaches to lymphoma immunotherapy such as CD20. B cell malignancies are also relatively sensitive to the cytokines that are produced by dendritic cells in response to CpG ODN. Thus, B cell malignancies appear to be uniquely sensitive to CpG ODN because of both the direct and indirect effects the CpG ODN on target cells and the sensitivity of B cell malignancies to an immune response. Preclinical studies support further exploration of the potential of CpG ODN as a component of therapy for lymphoid malignancies. Ongoing clinical trials are exploring the potential of CpG ODN, both alone and in combination with other agents.     

苯丁酸钠联合其他诱导分化剂治疗难治性白血病2例疗效观察

目的探讨苯丁酸钠在血液肿瘤诱导分化治疗中的应用方法。方法以苯丁酸钠为基础,同时加用ATRA、G-CSF、地塞米松。结果2例患者在治疗15 d后均取得了血液学改善,并取得了骨髓缓解。结论苯丁酸钠和其它诱导分化剂联合应用可能是部分血液肿瘤有效的诱导分化治疗方法。     

运动疗法联合重组人Ⅱ型肿瘤坏死因子受体——抗体融合蛋白治疗强直性脊柱炎的临床疗效观察

目的:探讨运动疗法联合重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白(rh TNFR-Fc)治疗强直性脊柱炎(AS)的疗效。方法:将120例AS患者按临床症状分为早、中和晚期三个组,每个组分别接受运动疗法联合rh TNFRFc治疗和rh TNFR-Fc单药治疗,治疗12周,对比不同疗法的组间疗效。结果:联合治疗组与单药治疗组的AS疗效评价标准20%(ASAS20)改善率分别为78.7%和55.9%,差异有统计学意义(P<0.05)。早期和中期AS患者中联合治疗组ASAS20改善率以及C-反应蛋白(CRP)和红细胞沉降率(ESR)的改善均显著优于单药治疗组(P<0.05)。结论:运动疗法联合rh TNFR-Fc治疗AS疗效优于单药治疗,且早中期AS患者采取运动疗法联合rh TNFR-Fc疗效更显著。     

Heterogeneous surface-modified nanoplatforms for the targeted therapy of haematological malignancies

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Recent developments in the systemic therapy of advanced gastroesophageal malignancies

Cancers of the upper gastrointestinal tract are a common cause of worldwide morbidity and mortality. The prognosis for patients with these cancers remains poor and only a minority of patients are cured. Systemic therapy has been used to treat patients with advanced disease but outcomes have not improved dramatically in the past few decades. Newer, more effective agents are desperately needed, and agents such as the taxanes (docetaxel and paclitaxel), irinotecan, oxaliplatin and capecitabine have recently shown some promise. In addition, molecularly targeted, non-cytotoxic therapies are being evaluated with the hope of improving the available therapeutic options. This article reviews the current clinical data regarding systemic therapy for patients with advanced upper gastrointestinal malignancies.     

Recent developments in the systemic therapy of advanced gastroesophageal malignancies

Cancers of the upper gastrointestinal tract are a common cause of worldwide morbidity and mortality. The prognosis for patients with these cancers remains poor and only a minority of patients are cured. Systemic therapy has been used to treat patients with advanced disease but outcomes have not improved dramatically in the past few decades. Newer, more effective agents are desperately needed, and agents such as the taxanes (docetaxel and paclitaxel), irinotecan, oxaliplatin and capecitabine have recently shown some promise. In addition, molecularly targeted, non-cytotoxic therapies are being evaluated with the hope of improving the available therapeutic options. This article reviews the current clinical data regarding systemic therapy for patients with advanced upper gastrointestinal malignancies.     

Vaccine therapy for non-Hodgkin's lymphoma and other B-cell malignancies

Immunity against tumor antigens, including the passive transfer of humoral (antibody-based) immunity or cellular immunity in the form of cytotoxic T-lymphocyte clones, has been exploited for the treatment of non-Hodgkin's lymphoma and other B-cell malignancies in recent years. In many strategies, the idiotype expressed on B-cell malignancies is the antigen used to induce active immunity. Early studies using purified idiotype, immune adjuvant and cytokines to induce anti-idiotype immunity have demonstrated that these methods are safe and potentially effective, and they are now being tested in prospective, randomized clinical trials. Methods for improvement include recombinant sources of idiotype, DNA vectors, enhancement of antigen delivery and presentation by using dendritic cells, boosting immune help through the use of cytokine delivery or foreign antigens, and blocking negative regulators. The goal of this approach is to induce lasting and individualized immunity against B-cell malignancies that is readily available and cost-effective.     

高迁移率族蛋白B1与恶性血液病

高迁移率族蛋白B1(high mobility group protein B1,HMGB1)是一种非组蛋白,可参与DNA转录,维持基因稳定,另外还可介导炎症反应,对于肿瘤的生长、转移等均有影响.近年来,已有研究证明HMGB1在各种淋巴瘤、白血病、骨髓增生异常综合(MDS)征等恶性血液疾病中呈高表达状态,并且依赖不同的机制实现其生物学效应.在治疗上使用HMGB1中和抗体还可增加恶性血液病对化疗药物的敏感性,HMGB1作为恶性血液病的治疗靶点越来越受到重视,该文就HMGB1的基本特征,HMGB1在恶性血液疾病中当前的研究进展以及其发展前景作一综述.     

Design of a bifunctional fusion protein for ovarian cancer drug delivery: single-chain anti-CA125 core-streptavidin fusion protein.

We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread.     

融合蛋白技术在生物医药领域中的应用

在治疗性药物的研发中,效应分子与人免疫球蛋白IgG1 Fc片段或人血清白蛋白形成的融合蛋白疗效不变,但体内半衰期明显延长、药物耐受性增加、副作用减少.在疫苗研发中,抗原分子与毒素分子或Fc形成的融合蛋白是很好的新型疫苗,并能激发细胞免疫.     

内皮抑素融合蛋白的发酵与纯化

目的对内皮抑素融合蛋白的发酵和纯化工艺进行研究。方法利用 5L发酵罐 ,设定了溶氧、搅拌速度、补液量、补液时机和补液速度等发酵条件 ;用硫酸铵分级沉淀、凝胶过滤、离子交换色谱等方法纯化目的蛋白质。结果工程菌目的蛋白质表达量占菌体总蛋白质的 2 0 % ;纯化后纯度达 95 %以上。结论研讨了大肠杆菌高效表达内皮抑素融合蛋白发酵及纯化工艺 ,为实际应用奠定了基础。     

融合蛋白技术在生物医药领域中的应用

在治疗性药物的研发中,效应分子与人免疫球蛋白IgG1 Fc片段或人血清白蛋白形成的融合蛋白疗效不变,但体内半衰期明显延长、药物耐受性增加、副作用减少.在疫苗研发中,抗原分子与毒素分子或Fc形成的融合蛋白是很好的新型疫苗,并能激发细胞免疫.     

Diphtheria toxin mutant CRM197 is an inhibitor of protein synthesis that induces cellular toxicity.

Diphtheria toxin (DT) ADP-rybosylates elongation factor-2 on a modified histidine residue called diphthamide, leading to a block in protein synthesis. CRM197 is a nontoxic DT mutant commonly used as a carrier for conjugate vaccines, and may have a potential as an anti-tumor agent. We now report that CRM197 expression is indeed toxic to cells, and inhibits protein synthesis. These results should be considered for future vaccine studies, and to investigate the mechanism of CRM197-mediated anti-tumor effect.