Maraba Virus as a Potent Oncolytic Vaccine Vector

The rhabdovirus Maraba has recently been characterized as a potent oncolytic virus. In the present study, we engineered an attenuated Maraba strain, defined as MG1, to express a melanoma-associated tumor antigen. Its ability to mount an antitumor immunity was evaluated in tumor-free and melanoma tumor-bearing mice. Alone, the MG1 vaccine appeared insufficient to prime detectable adaptive immunity against the tumor antigen. However, when used as a boosting vector in a heterologous prime-boost regimen, MG1 vaccine rapidly generated strong antigen-specific T-cell immune responses. Once applied for treating syngeneic murine melanoma tumors, our oncolytic prime-boost vaccination protocol involving Maraba MG1 dramatically extended median survival and allowed complete remission in more than 20% of the animals treated. This work describes Maraba virus MG1 as a potent vaccine vector for cancer immunotherapy displaying both oncolytic activity and a remarkable ability to boost adaptive antitumor immunity.     

血液感染性病毒核酸检测室内质量控制方法的研究

目的 探讨合适血液感染性病毒核酸检测（nucleic acid testing, NAT）的室内质量控制（internal quality control,IQC）方法。方法 使用北京康彻斯坦质控品（常规质控品）和澳大利亚国立血清学参比实验室（National SerologicalReference Laboratory, NRL）QConnect 质控品（评估质控品）进行血液感染性病毒核酸平行检测。收集2 种质控品的检测结果,在常规质控方法判断为在控的检测批次中,再分别采用Westgard 多规则质控方法和NRL 质控限质控方法进行判断,观察2 种质控方法假失控的次数和比例。结果 在常规质控方法判断在控的实验批次中,再次使用Westgard 多规则质控方法分析,HBV DNA,HCV RNA 和HIV RNA 三项仍各有0 ～ 2.46%（罗氏核酸混样检测）和0.73% ～ 2.55%（盖立复核酸单人份检测）比例的假失控。使用NRL QConnect 质控品在常规质控方法判断在控的盖立复检测批次中,使用NRL 质控限进行室内质控,未发现失控情况。使用NRL QConnect 质控品,在常规质控方法判断在控的罗氏检测批次中,使用NRL 质控限的计算方法,计算该实验室的质控限,发现在HBV DNA 和HIV RNA 检测中各有1 次失控（0.30%）。结论 Westgard 多规则质控方法不适合用于目前血站血液感染性病毒核酸检测的室内质控。该文浓度的NRL QConnect质控品和NRL 质控限适合用于国内盖立复核酸单人份检测方法的室内质控,但该浓度不适合用于国内罗氏核酸混样检测。该实验室在用的室内质控方法与NRL 质控限的室内质控方法,均适用于国内罗氏核酸混样检测和盖立复核酸单人份检测的室内质控。     

Complete Eradication of Xenograft Hepatoma by Oncolytic Adenovirus ZD55 Harboring TRAIL-IETD-Smac Gene with Broad Antitumor Effect

Abstract Cancer-targeting dual-gene virotherapy (CTGVT-DG) is an important modification of CTGVT, in which two suitable genes are used to obtain an excellent antitumor effect. A key problem is to join the two genes to form one fused gene, and then to clone it into the oncolytic viral vector so that only one investigational new drug application, instead of two, is required for clinical use. Many linkers (e.g., internal ribosome entry site) are used to join two genes together, but they are not all equally efficacious. Here, we describe finding the best linker, that is, sequence encoding the four amino acids IETD, to join the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and the second mitochondria-derived activator of caspase (Smac) gene to form TRAIL-IETD-Smac and inserting it into oncolytic viral vector ZD55 to construct ZD55-TRAIL-IETD-Smac, which matched ZD55-TRAIL plus ZD55-Smac in completely eliminating xenograft hepatoma. ZD55-TRAIL-IETD-Smac works by quantitative cleavage at IETD↓by inducing caspase-8; activation or inhibition of caspase-8 could up- or downregulate cleavage, respectively. The cleaved product, TRAIL-IETD, does not affect the function of TRAIL. Numerous experiments have shown that the combined use of ZD55-TRAIL plus ZD55-X could completely eradicate many xenograft tumors, and therefore the IETD is potentially a useful linker to construct many antitumor drugs, for example, ZD55-TRAIL-IETD-X, where X has a compensative or synergetic effect on TRAIL. We found that the antitumor effect of ZD55-IL-24-IETD-TRAIL also has an equivalent antitumor effect compared with the combined use of ZD55-IL-24 plus ZD55-TRAIL, because ZD55-IL-24 could also induce caspase-8. This means that IETD, as a two-gene linker, may have broad use.     

核酸扩增技术（NAT）在献血者血液初筛中的应用现状

随着输血在临床中的应用越来越广泛,对输血传播疾病问题的研究也就越来越受到重视.直到20世纪90年代,针对输血传播疾病的初筛完全依赖于血清学试验,除了乙型肝炎病毒（HBV）可以使用乙型肝炎表面抗原（HBsAg）检测以外,其他病毒的检测基本上都是检测抗体的方法.分子技术（如PCR）的出现,为提高献血者的血液初筛检出率,降低经血传播疾病这种风险提供了可能.本文对国内外核酸扩增技术在献血者血液初筛中的应用现状进行了回顾.     

RT-PCR法观察光化学法损伤VSV核酸的动态变化

目的 :了解光化学灭活病毒时 ,VSV核酸的动态变化。方法 :利用来源于VSV核衣壳蛋白基因的一对引物以RT PCR法检测VSV的核酸。结果 :RT PCR最大检测灵敏度为 1 8LgTCID50 ;在VSV光化学灭活过程中 ,RT PCR产物量在 5个灭活时间段上是不同的 ,随灭活时间的延长而减少。结论 :光化学法对VSV核酸损伤程度随病毒灭活时间的延长而增大。     

醋酸棉酚诱导多发性骨髓瘤细胞凋亡及其机制的实验研究

本研究探讨醋酸棉酚对经典人多发性骨髓瘤细胞系RPMI8226的作用及其机制。采用四唑盐比色试验（MTT）、细胞形态学观察、流式细胞仪检测、DNA电泳、Western—blot等方法分剐观察醋酸棉酚对RPMI8226细胞的抑制增殖、诱导凋亡效应及其机制。结果表明：醋酸棉酚在〉16μmol／L浓度时可显著抑制RPMI8226细胞的增殖、促进其凋亡,随着剂量的增加以及时间的延长,效应越明显。研究还发现,醋酸棉酚是通过抑制线粒体膜电位（△ψm）、诱导Bax、Caspase-3等凋亡相关蛋白的表达来实现上述效应的。结论：醋酸棉酚对多发性骨髓瘤RPMI8226细胞具有选择性抑制增殖、促进凋亡的效应。     

Pre-existing Immunity and Passive Immunity to Adenovirus 5 Prevents Toxicity Caused by an Oncolytic Adenovirus Vector in the Syrian Hamster Model

We have used Syrian hamsters to examine the role of pre-existing immunity to adenovirus (Ad) 5 in the toxicity of the oncolytic Ad vector INGN 007. Groups of hamsters were or were not immunized with Ad5. Half the hamsters were immunosuppressed using cyclophosphamide (CP), then injected intravenously (i.v.) with 3× the maximum tolerated dose (MTD) of INGN 007 (in immunocompetent hamsters), and toxicity and vector replication in the liver were quantitated. In nonimmunized immunocompetent hamsters, toxicity was observed early but the hamsters recovered by day 6 after vector injection. In nonimmunized immunosuppressed hamsters, the vector was lethal by 3 days. Pre-existing neutralizing antibody (NAb) prevented liver infection and hepatotoxicity in both immunocompetent and immunosuppressed hamsters. In another study, passive immunization of immunosuppressed hamsters 1 day before a lethal dose (1× MTD) of INGN 007 prevented liver infection and replication, but immunization 1 day after vector administration was barely effective. When immunosuppressed hamsters were passively immunized 1 day after injection of 1/3rd the MTD of INGN 007, then significant protection was observed against liver infection and toxicity. Therefore, serum NAb are sufficient to prevent oncolytic Ad vector liver infection and toxicity. We saw no evidence that pre-existing immunity was associated with increased vector toxicity.     

Inhibition of Aggregation of Mutant Huntingtin by Nucleic Acid Aptamers In Vitro and in a Yeast Model of Huntington's Disease

Elongated polyglutamine stretch in mutant huntingtin (mhtt) correlates well with the pathology of Huntington''s disease (HD). Inhibition of aggregation of mhtt is a promising strategy to arrest disease progression. In this work, specific, high-affinity RNA aptamers were selected against monomeric mhtt (51Q-htt). Some of them inhibited its aggregation in vitro by stabilizing the monomer. They also recognized 103Q-htt but not 20Q-htt (nonpathogenic length). Inhibition of aggregation corresponded with reduced leakage of a fluorescent probe from liposomes and diminished oxidative stress in RBCs. The presence of aptamers was able to rescue the sequestration of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by aggregated mhtt. Some of the aptamers were able to enhance the partitioning of mhtt in the soluble fraction in a yeast model of HD. They were also able to rescue endocytotic defect due to aggregation of mhtt. The beneficial effect of a combination of aptamers was enhanced with improvement in cell survival. Since HD is a monogenic autosomal dominant disorder, aptamers may be developed as a viable strategy to slow down the progress of the disease. Since they are nonimmunogenic and nontoxic, aptamers may emerge as strong candidates to reduce protein–protein interaction and hence protein aggregation in protein misfolding disorders in general.     

Antisense Growth Inhibition of Methicillin-Resistant Staphylococcus aureus by Locked Nucleic Acid Conjugated with Cell-Penetrating Peptide as a Novel FtsZ Inhibitor

Methicillin-resistant Staphylococcus aureus (MRSA) infections are becoming increasingly difficult to treat, owing to acquired antibiotic resistance. The emergence and spread of MRSA limit therapeutic options and require new therapeutic strategies, including novel MRSA-active antibiotics. Filamentous temperature-sensitive protein Z (FtsZ) is a highly conserved bacterial tubulin homologue that is essential for controlling the bacterial cell division process in different species of S. aureus. We conjugated a locked nucleic acid (LNA) that targeted ftsZ mRNA with the peptide (KFF)₃K, to generate peptide-LNA (PLNA). The present study aimed to investigate whether PLNA could be used as a novel antibacterial agent. PLNA787, the most active agent synthesized, exhibited promising inhibitory effects on four pathogenic S. aureus strains in vitro. PLNA787 inhibited bacterial growth and resolved lethal Mu50 infections in epithelial cell cultures. PLNA787 also improved the survival rates of Mu50-infected mice and was associated with reductions of bacterial titers in several tissue types. The inhibitory effects on ftsZ mRNA and FtsZ protein expression and inhibition of the bacterial cell division process are considered to be the major mechanisms of PLNA. PLNA787 demonstrated activity against MRSA infections in vitro and in vivo. Our findings suggest that ftsZ mRNA is a promising new target for developing novel antisense antibiotics.     

Suppression of Cancer Growth by Nonviral Gene Therapy Based on a Novel Reactive Oxygen Species-responsive Promoter

Increased reactive oxygen species (ROS) production has been reported as a distinctive feature of different pathologies including cancer. Therefore, we assessed whether increased ROS production in the cancer microenvironment could be selectively exploited to develop a selective anticancer therapy. For this purpose, we constructed a novel chimeric promoter, based on a ROS-response motif located in the VEGF gene promoter placed, in turn, downstream of a second ROS-response motif obtained from the early growth response 1 (Egr-1) gene promoter. The activity of the chimeric promoter was largely dependent on variations in intracellular ROS levels and showed a high inducible response to exogenous H₂O₂. Transient expression of the thymidine kinase (TK) gene driven by the chimeric promoter, followed by gancyclovir (GCV) administration, inhibited human colorectal cancer and melanoma cell growth in vitro and in vivo. Moreover, electrotransfer of the TK gene followed by GCV administration exerted a potent therapeutic effect on established tumors. This response was improved when combined with chemotherapeutic drugs. Thus, we show for the first time that a distinctive pro-oxidant state can be used to develop new selective gene therapeutics for cancer.     

Inhibition of Multidrug-resistant Acinetobacter baumannii by Nonviral Expression of hCAP-18 in a Bioengineered Human Skin Tissue

When skin is compromised, a cascade of signals initiates the rapid repair of the epidermis to prevent fluid loss and provide defense against invading microbes. During this response, keratinocytes produce host defense peptides (HDPs) that have antimicrobial activity against a diverse set of pathogens. Using nonviral vectors we have genetically modified the novel, nontumorigenic, pathogen-free human keratinocyte progenitor cell line (NIKS) to express the human cathelicidin HDP in a tissue-specific manner. NIKS skin tissue that expresses elevated levels of cathelicidin possesses key histological features of normal epidermis and displays enhanced antimicrobial activity against bacteria in vitro. Moreover, in an in vivo infected burn wound model, this tissue results in a two log reduction in a clinical isolate of multidrug-resistant Acinetobacter baumannii. Taken together, these results suggest that this genetically engineered human tissue could be applied to burns and ulcers to counteract bacterial contamination and prevent infection.