间质干细胞荷载溶瘤腺病毒治疗肿瘤进展

溶瘤腺病毒是具有高度的肿瘤靶向性和良好的转染率,但全身应用后机体的免疫防御机制明显限制了溶瘤腺病毒的治疗效果。细胞荷载溶瘤腺病毒可能是克服这一瓶颈的有效策略,间质干细胞对肿瘤细胞有天然的靶向性同时可荷载溶瘤腺病毒提高抗肿瘤效果,本文主要对间质干细胞荷载溶瘤腺病毒治疗肿瘤的研究领域及研究进展进行综述。      

溶瘤腺病毒肿瘤靶向治疗：从实验室到临床

过去几十年从实验室到临床对溶瘤腺病毒进行了广泛的研究.有多种策略增强溶瘤腺病毒的肿瘤靶向性,包括将腺病毒基因组中参与细胞周期节点调控的功能基因(如E1A或E1B)进行突变或(和)利用肿瘤特异性启动子调控E1A基因的靶向转录调控,利用不同血清型腺病毒或RGD基序改变溶瘤腺病毒进入肿瘤细胞方式的靶向转导调控,以及利用细胞载体将溶瘤腺病毒传送至远处的肿瘤部位.溶瘤腺病毒作为一种载体,输送免疫调节基因或治疗性基因,通过增强抗肿瘤免疫,或引起肿瘤细胞凋亡、自杀等产生协同抗肿瘤效应.溶瘤腺病毒临床试验涉及到多种实体瘤,显示其临床应用是安全的,毒性作用轻至中度,患者能很好耐受,但有明确客观抗肿瘤反应的临床病例较少见,联合诸如化、放疗等治疗方法有助于提高临床效果. 未来的方向应强化溶瘤腺病毒免疫学相关机制的研究、突破妨碍溶瘤腺病毒研究的一些技术性瓶颈、优化细胞载体、提高溶瘤腺病毒远处传递的靶向性,以及寻找更具潜能的肿瘤干细胞作为靶点.此外,需要扩大临床试验的研究范围和加强与其他治疗方式特别是免疫治疗联合应用的研究.     

溶瘤腺病毒联合化疗治疗肿瘤的研究

近年来用溶瘤腺病毒联合化疗治疗肿瘤的研究备受人们关注.肿瘤细胞对化疗药物的耐药性是目前临床上有效应用化疗方案的主要限制.溶瘤腺病毒能明显提高传统化疗对肿瘤细胞的杀伤效果,克服了传统肿瘤基因治疗中复制缺陷型腺病毒的转染效率低、靶向性差、抗癌基因表达量低的缺点.在肿瘤治疗中溶瘤腺病毒联合化疗将可能成为潜在有效的临床治疗方案.     

靶向性溶瘤腺病毒治疗胰腺癌

采用溶瘤病毒靶向策略开展胰腺癌基因治疗研究是一个新的发展方向.目前相关研究有分子生物学、基因水平的体外实验和动物模型体内实验、靶向策略等,部分溶瘤腺病毒药物已进入Ⅲ期临床试验.溶瘤腺病毒单独使用或与其他治疗手段联合应用,能够增强抗肿瘤效应.     

靶向肿瘤的溶瘤腺病毒制备策略的研究进展

溶瘤腺病毒是指经过基因工程改造的腺病毒,其能够选择性地在肿瘤细胞中复制和表达,从而溶解肿瘤细胞;其可经过基因和衣壳蛋白层面的改造,特异性地结合和杀伤肿瘤细胞。自1996 年世界上第一例溶瘤腺病毒ONXY-015 开展临床研究以来,腺病毒在国内外广泛地应用于科学研究及转化应用,已有多个国家批准其在临床肿瘤治疗中使用,使用范围涉及到多种实体瘤。溶瘤腺病毒的改造方式多种多样,本文对溶瘤腺病毒治疗肿瘤的改造方法,如腺病毒的包膜蛋白进行修饰、腺病毒的结构基因进行改造、插入肿瘤特异性启动子、携带治疗基因与携带短发夹RNA和包括溶瘤病毒的多措施联合等研究进展作一综述。     

膀胱癌溶瘤腺病毒治疗研究进展

膀胱癌是常见的恶性肿瘤,绝大多数为非肌层浸润性膀胱癌。目前,传统的治疗方法仍不能治愈所有膀胱癌患者,膀胱内灌注化疗药物和免疫制剂治疗后失败的膀胱癌缺乏有效的治疗方法。近年来,溶瘤腺病毒治疗肿瘤的研究大量报道,膀胱癌由于给药方便、局部给药不会引起全身毒副作用而成为溶瘤腺病毒治疗的理想癌种。全文综述溶瘤腺病毒膀胱内灌注治疗膀胱癌的研究进展。     

溶瘤病毒联合放疗的基础与临床研究

溶瘤病毒可通过病毒复制导致肿瘤细胞裂解.目前已有大量针对呼肠孤病毒、麻疹病毒、单纯疱疹病毒及腺病毒等溶瘤病毒的作用机制、结构改造、临床安全性的研究,同时有研究证实溶瘤病毒联合放疗具有协同作用,并已进入临床研究阶段,故该治疗方法将成为有应用前景的抗肿瘤策略.     

双启动子调控的条件复制腺病毒制备及其体外抑瘤作用

目的:构建并制备survivin及hTERT双启动子调控的条件复制腺病毒,探讨其特异性溶瘤作用.方法:PCR方法分别扩增肿瘤特异性survivin及hTERT启动子,分别克隆入腺病毒载体pXC1的两个复制必需基因E1A和E1B序列上游启动子区,构建出双肿瘤特异性启动子调控的条件复制腺病毒载体pXC1-SP-TP;脂质体法与pBHGE3骨架质粒共转染293E细胞进行重组腺病毒包装,稀释法测定腺病毒滴度;应用MTT、活细胞计数等方法观察其对肝癌细胞HepG2的特异性溶瘤作用并以正常人的血管内皮细胞ECV304作为对照.结果:测序及双酶切鉴定结果证实,成功构建了双肿瘤特异性启动子调控复制腺病毒载体;在293E细胞中获得了重组腺病毒Ad-SP-TP,滴度测定显示病毒滴度达到3.9×1010TCID50/ml;MTT结果显示,Ad-SP-TP可有效抑制肝癌细胞增殖而对正常细胞无增殖抑制作用;活细胞计数及细胞形态观察结果显示,重组腺病毒在肝癌细胞中选择性复制并发挥溶细胞作用.结论:双启动子调控的腺病毒具有显著的溶瘤作用但对正常人血管内皮细胞不发挥溶细胞作用,实验结果为肝癌靶向治疗提供了更为良好的条件复制型病毒载体及新的治疗策略.     

溶瘤腺病毒治疗前列腺癌研究进展

摘 要：我国前列腺癌发病率呈逐年上升的趋势。早期前列腺癌有治愈可能,但进展期或转移性前列腺癌无法治愈。近年来,具有肿瘤选择性复制并杀伤肿瘤细胞而对正常细胞毒性较低的溶瘤腺病毒治疗前列腺癌的研究有诸多报道,临床前研究已经显示了其强大的溶瘤效果,临床研究也验证了其抗肿瘤效果和安全性,溶瘤腺病毒单独及联合放化疗治疗去势抵抗性前列腺癌的研究显示了一定的疗效。     

表达LAG-3抗体的溶瘤腺病毒对成胶质细胞瘤的抗瘤性

目的:探讨共表达淋巴细胞活化基因3(lymphocyte activation gene 3,LAG-3)抗体(LAG-3 antibody,aLAG)的溶瘤腺病毒对成胶质细胞瘤的抗肿瘤活性.方法:在溶瘤腺病毒Ad3的骨架中插入aLAG序列,获得重组溶瘤腺病毒Ad3-aLAG.应用WB法检测感染成胶质细胞瘤GL261细...     

Clinical Trials of Adenoviruses in Brain Tumors: A Review of Ad-p53 and Oncolytic Adenoviruses

Adenoviruses have been critical in the development of the molecular approaches to brain tumors. They have been engineered to function as vectors for delivering therapeutic genes in gene therapy strategies, and as direct cytotoxic agents in oncolytic viral therapies. This review outlines the uses of adenoviruses in brain tumor therapy by examining clinical trials of adenovirus-mediated p53 gene therapy and by reviewing the application of two conditionally replicative adenoviruses (CRAds) ONYX-015 and Delta 24 in brain tumors. The potential clinical use of CRAds that deliver trangenes, particularly p53, is also discussed.     

The potential of oncolytic virus therapy for pancreatic cancer

The objective of this paper was to review a new category of gene therapy using oncolytic viruses for the treatment of pancreatic cancer. The eligibility and feasibility of oncolytic virus therapy as a novel therapeutic agent against pancreatic cancer are discussed as well as basic research for clinical trials, including a historical perspective and the current status of these novel agents. Even combination therapy, such as surgery with radiation and chemotherapy, has not significantly improved the survival rate of pancreatic cancer. Recently, a clinical trial (phase I and II) using an oncolytic adenovirus, ONYX-015, was completed in patients with pancreatic cancer. The phase II trial yielded beneficial results (tumor reduction or stabilization) in about 50% of the patients. A phase I study of the efficacy of oncolytic herpes viruses, G207, OncoVEX GM-CSF, and 1716 against a variety of tumors has been completed, and G207 is in phase II trials for use against brain tumors. In addition, a phase I trial using the herpesvirus showed good tolerance at all dosages. We discuss the basic scientific principles and current results of the above clinical trials with respect to these oncolytic viruses, and then compare the relative advantages and disadvantages of adenoviruses and herpesviruses as oncolytic agents. We also review the published literature on newly developed oncolytic viruses. The concept of oncolytic therapy has been studied for a century. Recent technological developments have made these oncolytic viruses more tumor-specific by exploiting the tumor cell environments. In addition, these viruses have been reported to increase the immunosusceptibility of the tumor cells, and have been designed to express other genes to increase the susceptibility of tumor cells to other therapeutic agents. Oncolytic virus therapy certainly appears to be a feasible treatment for pancreatic cancer.     

Relaxin-expressing, fiber chimeric oncolytic adenovirus prolongs survival of tumor-bearing mice

Selective replication of oncolytic viruses in tumor cells provides a promising approach for the treatment of human cancers. One of the limitations observed with oncolytic viruses currently used in the treatment of solid tumors is the inefficient spread of virus throughout the tumor mass following intratumoral injection. Data are presented showing that oncolytic adenoviruses expressing the relaxin gene and containing an Ad5/Ad35 chimeric fiber showed significantly enhanced transduction and increased virus spread throughout the tumor when compared with non-relaxin-expressing, Ad5-based viruses. The increased spread of such viruses throughout tumors correlated well with improved antitumor efficacy and overall survival in two highly metastatic tumor models. Furthermore, nonreplicating viruses expressing relaxin did not increase metastases, suggesting that high level expression of relaxin will not enhance metastatic spread of tumors. In summary, the data show that relaxin may play a role in rearranging matrix components within tumors, which helps recombinant oncolytic adenoviruses to spread effectively throughout the tumor mass and thereby increase the extent of viral replication within the tumor. Expressing relaxin from Ad5/Ad35 fiber chimeric adenoviruses may prove a potent and novel approach to treating patients with cancer.     

Macrophage metalloelastase (MME) as adjuvant for intra-tumoral injection of oncolytic adenovirus and its influence on metastases development

Oncolytic adenoviruses are a promising treatment alternative for many advanced cancers, including colorectal cancer. However, clinical trials have demonstrated that single-agent therapy in advanced tumor masses is rarely curative. Poor spreading of the virus through tumor tissue is one of the major issues limiting efficacy. As oncolytic viruses kill preferentially cancer cells, high extracellular matrix (ECM) content constitutes potential barriers for viral penetration within tumors. In this study, the ECM-degrading proteases relaxin, hyaluronidase, elastase and macrophage metalloelastase (MME) were tested for their antitumor efficacy alone and in combination with oncolytic adenovirus. MME improved the overall antitumor efficacy of oncolytic adenovirus in subcutaneous HCT116 xenografts. In a liver metastatic colorectal cancer model, intra-tumoral treatment of primary tumors from HT29 cells with MME monotherapy or with oncolytic adenovirus inhibited tumor growth. Combination therapy showed no increased mortality in comparison with either monotherapy alone. Contradictory results of effects of MME on tumorigenesis and metastasis formation have been reported in the literature. This study demonstrates for the first time in a metastatic animal model that MME, as a monotherapy or in combination with oncolytic virus, does not increase tumor invasiveness. Co-administration of MME and oncolytic adenovirus may be a suitable approach for further optimization aiming at clinical applications for metastatic colorectal cancer.     

Therapeutic potential of replication-selective oncolytic adenoviruses on cells from familial and sporadic desmoid tumors

PURPOSE: Constitutive activation of the Wnt signaling pathway is a hallmark of many cancers and has been associated with familial and sporadic desmoid tumors. The aim of the present study is to assess the therapeutic potential of oncolytic adenoviruses selectively replicating in cells in which the Wnt signaling pathway is active on primary cells from desmoid tumors. EXPERIMENTAL DESIGN: Primary cells extracted from familial (n = 3) or sporadic (n = 3) desmoid tumors were cultured short term. Cancer cell survival and viral replication were measured in vitro upon infection with two different oncolytic adenoviruses targeting a constitutive activation of the Wnt signaling pathway. Adenoviral infectivity was also assessed. RESULTS: Although cells extracted from one sporadic desmoid tumor responded very well to the oncolytic action of the adenoviruses (<20% of viable cells upon infection at a multiplicity of infection of 10), cells from two tumor samples were totally resistant to the viral action. Cells from the remaining samples showed intermediate sensitivity to the oncolytic viruses. These effects were correlated to the level of infectivity of the cells. Finally, in responder cells, evidences of viral replication was observed. CONCLUSIONS: Our experimental data suggest that the response of desmoid tumor cells to oncolytic adenovirus is neither correlated to the type of mutation activating the Wnt signaling pathway nor to the familial or sporadic nature of the tumor. In addition, they highlight the variability of infectivity of individual tumors and predict a great variability in the response to oncolytic adenoviruses.     

Virus-associated RNA I-deleted adenovirus, a potential oncolytic agent targeting EBV-associated tumors

Given the growing number of tumor types recognizably associated with EBV infection, it is critically important that therapeutic strategies are developed to treat such tumors. Replication-selective oncolytic adenoviruses represent a promising new platform for anticancer therapy. Virus-associated I (VAI) RNAs of adenoviruses are required for efficient translation of viral mRNAs. When the VAI gene is deleted, adenovirus replication is impeded in most cells (including HEK 293 cells). EBV-encoded small RNA1 is uniformly expressed in most EBV-associated human tumors and can functionally substitute for the VAI RNAs of adenovirus. It enables replication to proceed through complementation of VAI-deletion mutants. We hypothesized that VAI-deleted adenovirus would selectively replicate in EBV-positive tumor cells due to the presence of EBV-encoded small RNA1 with no (or poor) replication in normal or EBV-negative tumor cells. In this report, we show that high levels of replication occurred in the VAI-deleted mutant in the EBV-positive tumor cells compared with low (or negligible) levels in EBV-negative and normal human primary cells. Correspondingly, high toxicity levels were observed in EBV-positive tumor cells but not in EBV-negative tumor or normal human primary cells. In vivo, VAI-deleted adenovirus showed superior antitumoral efficacy to wild-type adenovirus in EBV-positive tumor xenografts, with lower hepatotoxicity than wild-type adenovirus. Our data suggest that VAI-deleted adenovirus is a promising replication-selective oncolytic virus with targeting specificity for EBV-associated tumors.     

Use of replicating oncolytic adenoviruses in combination therapy for cancer.

Oncolytic virotherapy is the use of genetically engineered viruses that specifically target and destroy tumor cells via their cytolytic replication cycle. Viral-mediated tumor destruction is propagated through infection of nearby tumor cells by the newly released progeny. Each cycle should amplify the number of oncolytic viruses available for infection. Our understanding of the life cycles of cytolytic viruses has allowed manipulation of their genome to selectively kill tumor cells over normal tissue. Because the mechanism of tumor destruction is different, oncolytic virotherapy should work synergistically with current modes of treatment such as chemotherapy and radiation therapy. This article focuses on oncolytic adenoviruses that have been created and tested in preclinical and clinical trials in combination with chemotherapy, radiation therapy, and gene therapy.     

Intratumoral coadministration of hyaluronidase enzyme and oncolytic adenoviruses enhances virus potency in metastatic tumor models

PURPOSE: Evaluate the codelivery of hyaluronidase enzyme with oncolytic adenoviruses to determine whether it improves the spread of the virus throughout tumors, thereby leading to a greater overall antitumor efficacy in tumor models. EXPERIMENTAL DESIGN: The optimal dose of hyaluronidase that provided best transduction efficiency and spread of a green fluorescent protein (GFP)-expressing adenovirus within tumors was combined with oncolytic viruses in tumor models to determine whether the combination treatment results in an improvement of antitumor efficacy. RESULTS: In mice injected with the adenovirus Ad5/35GFP and an optimal dose of hyaluronidase (50 U), a significant increase in the number of GFP-expressing cells was observed when compared with animals injected with virus only (P < 0.0001). When the oncolytic adenoviruses Ad5OV or Ad5/35 OV (OV-5 or OV5T35H) were codelivered with 50 U of hyaluronidase, a significant delay in tumor progression was observed, which translated into a significant increase in the mean survival time of tumor-bearing mice compared with either of the monotherapy-treated groups (P < 0.0001). Furthermore, the mice that received the combination of Ad5/35 OV and hyaluronidase showed the best antitumor efficacy. Importantly, the combination treatment did not increase the metastatic potential of the tumors. Lastly, the increase in virus potency observed in animals injected with both enzyme and virus correlated with enhanced virus spread throughout tumors. CONCLUSION: Antitumor activity and overall survival of mice bearing highly aggressive tumors are significantly improved by codelivery of oncolytic adenoviruses and hyaluronidase when compared with either of the monotherapy-treated groups, and it may prove to be a potent and novel approach to treating patients with cancer.     

Oncolytic adenoviruses as antiglioma agents

The treatment for malignant gliomas is suboptimal. Oncolytic adenoviruses hold the promise of being effective agents for the treatment of solid tumors. Importantly, the first oncolytic viral therapy has just been approved for use in combination with chemotherapy for late-stage refractory nasopharyngeal cancer by the Chinese State FDA, following a successful Phase III randomized clinical trial. The concept underlying treatment with oncolytic adenoviruses is based on cancer selectivity by confining viral replication and infectivity to cancer cells. For this purpose, the main strategies used currently to modify the viruses include: functional deletions in essential viral genes; tumor- or tissue-specific promoters used to control the expression of these viral genes; and tropism modification to redirect adenovirus to the cancer cell surface. In the near future, oncolytic adenoviruses need to be optimized to fully realize their potential as critical anticancer tools and, thus, improve the prognosis for patients with malignant gliomas.