Suppression of tumor growth by oncolytic adenovirus-mediated delivery of an antiangiogenic gene, soluble Flt-1.

Armed oncolytic adenoviruses represent an appealing tumor treatment approach, as they can attack tumors at multiple levels. In this study, considering that angiogenesis plays a central role in tumor growth, we inserted an antiangiogenic gene, sflt-1(1-3) (the first three extracellular domains of FLT1, the hVEGF receptor-1), into an E1B-55-kDa-deleted oncolytic adenovirus (ZD55) to construct ZD55-sflt-1. Although soluble (s) Flt-1 did not affect tumor cell growth, ZD55-sflt-1 could specifically induce a cytopathic effect in tumor cells, like ONYX-015. The secretion of sFlt-1 from ZD55-sflt-1 was much higher than that from replication-deficient Ad-sflt-1 upon infection of SW620 human colon tumor cells, leading to a stronger inhibitory effect on VEGF-induced proliferation and tube formation ability of HUVECs. Moreover, marked reduction of tumor growth and long-term survival rates were observed in ZD55-sflt-1-treated nude mice with subcutaneous SW620 tumor. Its efficacy correlated with a decrease in microvessel density and an increase in apoptotic tumor cells. In addition, ZD55-sflt-1 showed a synergic effect with the chemotherapeutic agent 5-FU. These results indicate that ZD55-sflt-1, combining the advantages of oncolytic adenovirus and antiangiogenic gene therapy, is a powerful agent for human tumor treatment.     

热疗联合组织因子靶向治疗对人大肠癌细胞增殖及凋亡的影响

目的 探讨热疗联合组织因子(TF)靶向治疗在体内和体外对人大肠癌细胞增殖及凋亡的影响.方法 用RNA干扰的方法 敲低大肠癌LOVO细胞系中TF的表达,MTT法、流式细胞术、Western blot方法 测定热疗联合TF敲低对LOVO细胞体外增殖抑制及细胞凋亡的影响.将人大肠癌细胞注射到裸鼠腹股沟皮下建立裸鼠皮下移植瘤模型,观察不同治疗方法 对肿瘤生长的影响.结果 用RNA干扰的方法 可以有效降低大肠癌LOVO细胞系中TF的表达.与单独热疗和单独TF敲低相比,联合治疗能够明显抑制细胞增殖和促进细胞凋亡的发生(P<0.05).热疗联合TF敲低能够有效抑制裸鼠体内的肿瘤生长.结论 热疗和TF敲低联合应用能够抑制大肠癌细胞增殖并且诱导其凋亡,热疗联合TF靶向治疗是一个潜在的治疗大肠癌的新策略.     

Potent antitumor efficacy of ST13 for colorectal cancer mediated by oncolytic adenovirus via mitochondrial apoptotic cell death

ST13 is a cofactor of heat shock protein 70 (Hsp70). To date, all data since the discovery of ST13 in 1993 until more recent studies in 2007 have proved that ST13 is downregulated in tumors and it was proposed to be a tumor suppressor gene, but no work reported its antitumor effect and apoptotic mechanism. In the work described in this paper, ST13 was inserted into ZD55, an oncolytic adenovirus with the E1B 55-kDa gene deleted, to form ZD55-ST13, which exerts an excellent antitumor effect in vitro and in an animal model of colorectal carcinoma SW620 xenograft. ZD55-ST13 inhibited tumor cells 100-fold more than Ad-ST13 and ZD55-EGFP in vitro. However, ZD55-ST13 showed no damage of normal fibroblast MRC5 cells. In exploring the mechanism of ZD55-ST13 in tumor cell killing, we found that ZD55-ST13-infected SW620 cells formed apoptotic bodies and presented obvious apoptosis phenomena. ZD55-ST13 induced the upregulation of Hsp70, the downregulation of antiapoptotic gene Bcl-2, and the release of cytochrome c. Cytochrome c triggered apoptosis by activating caspase-9 and caspase-3, which cleave the enzyme poly(ADP-ribose) polymerase in ZD55-ST13-infected SW620 cells. In summary, overexpressed ST13 as mediated by oncolytic adenovirus could exert potent antitumor activity via the intrinsic apoptotic pathway and has the potential to become a novel therapeutic for colorectal cancer gene therapy.     

Potent antitumor activity of oncolytic adenovirus expressing mda-7/IL-24 for colorectal cancer

It has been demonstrated that interleukin 24 (IL-24, also called melanoma differentiation associated gene 7) exerts antitumor activity. In this study, we investigated whether oncolytic adenovirus-mediated gene transfer of IL-24 could induce strong antitumor activity. A tumor-selective replicating adenovirus expressing IL-24 (ZD55-IL-24) was constructed by insertion of an IL-24 expression cassette into the ZD55 vector, which is based on deletion of the adenoviral E1B 55-kDa gene. ZD55-IL-24 could express substantially more IL-24 than Ad-IL-24 because of replication of the vector. It has been shown that ZD55-IL-24 exerted a strong cytopathic effect and significant apoptosis in tumor cells with p53 dysfunction. Moreover, no cytotoxic and apoptotic effects could be seen in normal cells infected with ZD55-IL-24. Expression of IL-24 did not interfere with viral replication induced by oncolytic adenovirus. Activation of caspase 3 and caspase 9, and induction of bax gene expression, were involved in tumor cell apoptosis induced by ZD55-IL-24. Treatment of established tumors with ZD55-IL-24 showed much stronger antitumor activity than that induced by ONYX-015 or Ad-IL- 24. These data indicated that oncolytic adenovirus expressing IL-24 could exert potential antitumor activity and offer a novel approach to cancer therapy.     

Effective gene-virotherapy for complete eradication of tumor mediated by the combination of hTRAIL (TNFSF10) and plasminogen k5.

Virotherapy with oncolytic viruses is a highly promising approach for cancer therapy. To improve further the therapeutic effect of oncolytic viruses, therapeutic genes have been incorporated into these types of vectors. In this study, we have inserted hTRAIL (approved gene symbol TNFSF10) into the ZD55 vector, which was based on deletion of the adenoviral E1B 55-kDa gene and could replicate in and lyse p53-deficient tumors. Our data shows that infection of colorectal carcinoma cells with ZD55-hTRAIL resulted in tumor cell death that was much greater than that induced by ZD55 vector or replication-defective adenovirus expressing hTRAIL. In contrast to these, ZD55-hTRAIL did not induce any cytopathic effect in normal cells. Treatment of established tumor with ZD55-hTRAIL resulted in dramatic inhibition of tumor growth in an animal model of colorectal carcinoma. However, when the established tumors were treated by coadministration of ZD55-hTRAIL and Ad-k5, we observed complete eradication of the established tumors in all animals treated with the combined therapy. This strong anti-tumor activity was due to the fact that two genes may act with compensative (or synergic) effect through different mechanisms to kill tumors. Therefore, targeting dual gene-virotherapy may be one of the best strategies for cancer therapy if two suitable genes are chosen.     

Cancer targeting Gene-Viro-Therapy of liver carcinoma by dual-regulated oncolytic adenovirus armed with TRAIL gene

Liver cancer is a common and aggressive malignancy, but available treatment approaches remain suboptimal. Cancer targeting Gene-Viro-Therapy (CTGVT) has shown excellent anti-tumor effects in a preclinical study. CTGVT takes advantage of both gene therapy and virotherapy by incorporating an anti-tumor gene into an oncolytic virus vector. Potent anti-tumor activity is achieved by virus replication and exogenous expression of the anti-tumor gene. A dual-regulated oncolytic adenoviral vector designated Ad·AFP·E1A·E1B (Δ55) (Ad·AFP·D55 for short thereafter) was constructed by replacing the native viral E1A promoter with the simian virus 40 enhancer/α-fetoprotein (AFP) composite promoter (AFPep) based on an E1B-55K-deleted construct, ZD55. Ad·AFP·D55 showed specific replication and cytotoxicity in AFP-positive hepatoma cells. It also showed enhanced safety in normal cells when compared with the mono-regulated vector ZD55. To improve the anti-hepatoma activities of the virus, the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene was introduced into Ad·AFP·D55. Ad·AFP·D55-TRAIL exhibited remarkable anti-tumor activities in vitro and in vivo. Treatment with Ad·AFP·D55-TRAIL can induce both autophagy owing to the Ad·AFP·D55 vector and caspase-dependent apoptosis owing to the TRAIL protein. Therefore, Ad·AFP·D55-TRAIL could be a potential anti-hepatoma agent with anti-tumor activities due to AFP-specific replication and TRAIL-induced apoptosis.     

An NGR-integrated and enediyne-energized apoprotein shows CD13-targeting antitumor activity

Targeting and inhibiting angiogenesis is a promising strategy for treatment of cancer. NGR peptide motif is a tumor-homing peptide, which could bind with CD13 expressed on tumor blood vessels. Lidamycin is a highly potent antitumor antibiotic, which is composed of an apoprotein (LDP) and an active enediyne chromophore (AE). Here, an NGR-integrated and enediyne-energized apoprotein composed of cyclic NGR peptide and lidamycin was developed by a two-step procedure. Firstly, we prepared the fusion protein composed of NGR peptide and LDP by recombinant DNA technology. Then, AE was reloaded to the fusion protein to get NGR-LDP-AE. Our experiments showed that NGR-LDP could bind to CD13-expressing HT-1080 cells, whereas the recombinant LDP (rLDP) showed weak binding. NGR-LDP-AE exerted highly potent cytotoxicity to cultured tumor cells in vitro. In vivo antitumor activity was evaluated in murine hepatoma 22 (H22) model and human fibrosarcoma HT-1080 model. At the tolerable dose, NGR-LDP-AE and lidamycin inhibited H22 tumor growth by 94.8 and 66.9%, and the median survival time of the mice was 62 and 37 days, respectively. In the HT-1080 model, NGR-LDP-AE inhibited tumor growth by 88.6%, which was statistically different from that of lidamycin (74.5%). Immunohistochemical study showed that NGR-LDP could bind to tumor blood vessels. Conclusively, these results demonstrate that fusion of LDP with CNGRC peptide delivers AE to tumor blood vessels and improves its antitumor activity.     

携带TRAIL的溶瘤腺病毒治疗三阴性乳腺癌的研究

目的：构建携带肿瘤坏死因子相关凋亡诱导配体（tumor necrosis factor-related apoptosis inducing ligand,TRAIL）基因的溶瘤腺病毒p55-hTERT-HRE-TRAIL,评估该病毒在体外和体内对三阴性乳腺癌的杀伤能力.方法：将质粒p55-hTERT-HRE与pPE3-TRAIL通过Lipofectamine 2000共转染至人胚肾293细胞,获得溶瘤腺病毒p55-hTERT-HRE-TRAIL;采用病毒体外增殖实验观察乳腺癌细胞株MDA-MB-231和人正常乳腺细胞株MCF-10A中的增殖情况;采用四甲基偶氮唑蓝（MTT）比色法比较不同感染复数（multiplicity of infection,MOI）的病毒对两种细胞的抑制效应;采用酶联免疫吸附试验（ELISA）法检测病毒感染细胞后上清液中TRAIL的含量,采用蛋白质印迹（Western blotting）法检测细胞内TRAIL蛋白的表达.建立三阴性乳腺癌的原位成瘤模型及左心室注射模拟转移瘤裸鼠模型,应用“活体内光学成像系统”动态观察肿瘤的生长及转移情况.结果：p55-hTERT-HRE-TRAIL感染乳腺癌细胞株后表现出强大的增殖、复制能力,而在人正常乳腺细胞株内增殖并不明显;很低浓度的p55-hTERT-HRE TRAIL就对乳腺癌细胞产生明显的杀伤效应,而对正常乳腺细胞没有明显的杀伤作用;p55-hTERT-HRE-TRAIL感染乳腺癌细胞后,TRAIL蛋白的表达明显增多,而感染正常乳腺细胞后表达的TRAIL维持在较低的水平.乳腺癌原位成瘤模型中,空白对照组的光子数多于其他各组,肿瘤体积大于其他各组（P＜0.05）.左心室注射模拟转移瘤模型中,对照组活体内光学成像与TRAIL治疗组差异有统计学意义,TRAIL治疗组的生存天数延长（P＜0.05）.结论：成功构建高滴度的溶瘤腺病毒p55-hTERT-HRE-TRAIL,该病毒在乳腺癌细胞中具有特异性增殖并杀伤肿瘤细胞的能力.     

ZD6474, a vascular endothelial growth factor receptor tyrosine kinase inhibitor with additional activity against epidermal growth factor receptor tyrosine kinase, inhibits orthotopic growth and angiogenesis of gastric cancer

Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) have been strongly implicated in the growth and metastasis of gastric cancer. The purpose of this study was to examine the effects of ZD6474, an inhibitor of inhibitor of VEGF receptor (VEGFR) tyrosine kinase with additional activity against EGF receptor (EGFR), on tumor growth and angiogenesis in an orthotopic model of gastric cancer. In vitro, ZD6474 inhibited human umbilical vascular endothelial cell and TMK-1 human gastric tumor cell proliferation in a dose-dependent fashion. EGF-mediated activation of EGFR and Erk-1/2 was decreased in tumor cells after ZD6474 treatment. In addition, VEGF-mediated activation of VEGFR2 and Erk-1/2 was decreased in human umbilical vascular endothelial cells. TMK-1 human gastric adenocarcinoma cells were injected into the gastric wall of nude mice. ZD6474 therapy was initiated on day 10. Mice (n = 14 per group) were treated p.o. with (a) 1% Tween 80 (control), (b) 50 mg/kg/d ZD6474, or (c) 100 mg/kg/d ZD6474. Mice were sacrificed on day 33. Tumors from each group were stained for markers of blood vessels, pericytes, proliferation, and apoptosis. ZD6474 at both 50 and 100 mg/kg/d led to marked inhibition of tumor growth (P < 0.05). ZD6474 reduced tumor cell proliferation by 48% in the 50 mg/kg/d group and 65% in the 100 mg/kg/d group (P < 0.03) and increased tumor cell apoptosis (P < 0.001) in vivo. ZD6474 led to a 69% decrease in microvessel density in the 50 mg/kg/d group (P < 0.001) and a 62% decrease in the 100 mg/kg/d group (P < 0.001). Although microvessel density was decreased by ZD6474, the remaining vessels showed a relatively higher percentage of pericyte coverage (3-fold increase; P < 0.001), perhaps reflecting selective loss of uncovered vessels in the ZD6474 group. In conclusion, therapies such as ZD6474 that target two distinct aspects of tumor growth, angiogenesis and tumor cell proliferation, warrant further investigation.     

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.     

The pro-apoptotic protein,Bik, exhibits potent antitumor activity that is dependent on its BH3 domain

The Bcl-2 homology 3 (BH3) domain is present in most members of the Bcl-2 protein family and is required to confer the death-inducing properties of pro-apoptotic members, including Bax, Bak, Bad, and Bik, in cell-based assay systems. To determine whether the BH3 domain possesses a similar role in tumor tissues in vivo, we overexpressed the wild-type Bik protein and its BH3-deleted counterpart, using adenoviral technology, in chemoresistant human tumor prostate (PC-3) and colon (HT-29) cell lines growing in vitro and in vivo. Bik caused apoptosis in both PC-3 and HT-29 cells in vitro by inducing the release of cytochrome c from mitochondria to cytoplasm, resulting in the catalytic activation of caspases 9, 7, and 3 and cleavage of poly(ADP-ribose) polymerase and DNA fragmentation. When the BH3 domain was deleted from the Bik protein, no effect on mitochondrial activity or cell morphology could be observed. Furthermore, intratumoral injection of an adenovirus vector expressing the Bik gene, but not the deleted BH3 Bik gene, suppressed the growth of PC-3 and HT-29 xenografts established in nude mice. Histological examination of tumors from mice treated with the wild-type Bik adenoviral construct demonstrated cellular debris, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling positive staining, and morphological changes associated with apoptosis. In contrast, tissue sections obtained from tumors treated with the BH3-deleted Bik adenoviral construct showed no evidence of apoptosis. Thus, our results suggest that the BH3 domain is required for the antitumor activity of the Bik protein and provides a novel therapeutic approach for cancer therapy.     

RNAi targeting CXCR4 inhibits tumor growth through inducing cell cycle arrest and apoptosis

CXC chemokine receptor 4 (CXCR4) is involved in many human malignant tumors and plays an important role in tumor growth and metastasis. To explore the effects of CXCR4 expression on the malignant cells of oral squamous cell carcinoma (OSCC), Tca8113 and SCC-9 cell lines, as well as their xenograft models, of nude mice were used to detect cancer cell proliferation alteration. This study also examined the corresponding molecular mechanism after CXCR4 knockdown using a recombinant lentiviral vector expressing small interference RNA (siRNA) for CXCR4. RNA interference-mediated knockdown of CXCR4 in highly aggressive (Tca8113 and SCC-9) tumor cells significantly inhibited the proliferation of the two cell lines in vitro and in vivo. The expression levels of >1,500 genes involved in cell cycle, apoptosis, and multiple signaling pathways were also altered. These results provide new evidence of CXCR4 as a promising tumor gene therapeutic target.     

Pancratistatin selectively targets cancer cell mitochondria and reduces growth of human colon tumor xenografts

The naturally occurring Amaryllidaceae alkaloid pancratistatin exhibits potent apoptotic activity against a large panel of cancer cells lines and has an insignificant effect on noncancerous cell lines, although with an elusive cellular target. Many current chemotherapeutics induce apoptosis via genotoxic mechanisms and thus have low selectivity. The observed selectivity of pancratistatin for cancer cells promoted us to consider the hypothesis that this alkaloid targets cancer cell mitochondria rather than DNA or its replicative machinery. In this study, we report that pancratistatin decreased mitochondrial membrane potential and induced apoptotic nuclear morphology in p53-mutant (HT-29) and wild-type p53 (HCT116) colorectal carcinoma cell lines, but not in noncancerous colon fibroblast (CCD-18Co) cells. Interestingly, pancratistatin was found to be ineffective against mtDNA-depleted (ρ(0)) cancer cells. Moreover, pancratistatin induced cell death in a manner independent of Bax and caspase activation, and did not alter β-tubulin polymerization rate nor cause double-stranded DNA breaks. For the first time we report the efficacy of pancratistatin in vivo against human colorectal adenocarcinoma xenografts. Intratumor administration of pancratistatin (3 mg/kg) caused significant reduction in the growth of subcutaneous HT-29 tumors in Nu/Nu mice (n = 6), with no apparent toxicity to the liver or kidneys as indicated by histopathologic analysis and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Altogether, this work suggests that pancratistatin may be a novel mitochondria-targeting compound that selectively induces apoptosis in cancer cells and significantly reduces tumor growth.     

Potent antitumor effects of ZD6474 on neuroblastoma via dual targeting of tumor cells and tumor endothelium

Among children with relapsed or refractory neuroblastoma, the prognosis is poor and novel therapeutic strategies are needed to improve long-term survival. As with other solid tumors, high vascular density within neuroblastoma is associated with advanced disease, and therapeutic regimens directed against the tumor vasculature may provide clinical benefit. The receptor tyrosine kinase RET is widely expressed in neuroblastoma and is known to activate key signal transduction pathways involved in tumor cell survival and progression including Ras/mitogen-activated protein kinase and phosphatidylinositol 3-kinase/Akt. We investigated the effect of dual targeting of tumor cells and tumor endothelium with ZD6474, a small-molecule tyrosine kinase inhibitor of vascular endothelial growth factor (VEGF) receptor 2, epidermal growth factor receptor, and RET. ZD6474 inhibited the phosphorylation of RET in neuroblastoma cells and had a direct effect on tumor cell viability in seven neuroblastoma cell lines. In a human neuroblastoma xenograft model, ZD6474 inhibited tumor growth by 85% compared with treatment with vehicle alone. In contrast, no significant inhibition of tumor growth was observed after treatment with bevacizumab, an antihuman VEGF monoclonal antibody, or the epidermal growth factor receptor inhibitor erlotinib, either alone or in combination. Immunohistochemical analysis showed that ZD6474 treatment led to an increase in endothelial cell apoptosis along with inhibition of VEGF receptor-2 activation on tumor endothelium. In conclusion, dual targeting of tumor cells, potentially through RET inhibition, and tumor vasculature with ZD6474 leads to potent antitumor effects. This approach merits further investigation for patients with neuroblastoma.     

Deletion of VAI and VAII RNA genes in the design of oncolytic adenoviruses

Deletion of viral functions that can be complemented by the specific phenotype of tumor cells is a common strategy to design oncolytic viruses. For example, enhanced mRNA cytoplasmic export in tumor cells phenocopies the adenovirus E1B-55K function and renders mutants of this protein tumor selective. Also, an activated RB pathway complements specific E1A functions that can be deleted to produce oncolytic viruses. In this paper we demonstrate that an adenoviral mutant deleted in virus-associated I (VAI) and VAII RNAs (Ad-VAdel) has oncotropism characterized by 100-fold replication deficiency compared with wild-type adenovirus in normal cells and an unaffected ability to replicate and kill different types of tumor cells. This mutant also displays active antitumoral activity in vivo. In contrast, this oncotropism is less evident in a mutant expressing an inactive form of VAI (Adsub719) because VAII RNA expression is upregulated. The mRNA translation promoted by VA RNA genes can be phenocopied in tumor cells with the activation of signal transduction pathways, such as the Ras pathway.     

Hsp27 knockdown using nucleotide-based therapies inhibit tumor growth and enhance chemotherapy in human bladder cancer cells

Heat shock protein 27 (Hsp27) is a cytoprotective chaperone that is phosphoactivated during cell stress that prevents aggregation and/or regulate activity and degradation of certain client proteins. Recent evidence suggests that Hsp27 may be involved in tumor progression and the development of treatment resistance in various tumors, including bladder cancer. The purpose of this study was to examine, both in vitro and in vivo, the effects of overexpression of Hsp27 and, correspondingly, the down-regulation of Hsp27 using small interfering (si) RNA and OGX-427, a second-generation antisense oligonucleotide targeting Hsp27. Hsp27 overexpression increased UMUC-3 cell growth and resistance to paclitaxel. Both OGX-427 and Hsp27 siRNA decreased Hsp27 protein and mRNA levels by >90% in a dose- and sequence-specific manner in human bladder cancer UMUC-3 cells. OGX-427 or Hsp27 siRNA treatment induced apoptosis and enhanced sensitivity to paclitaxel in UMUC-3 cells. In vivo, OGX-427 significantly inhibited tumor growth in mice, enhanced sensitivity to paclitaxel, and induced significantly higher levels of apoptosis compared with xenografts treated with control oligonucleotides. Collectively, these findings suggest that Hsp27 knockdown with OGX-427 and combined therapy with paclitaxel could be a novel strategy to inhibit the progression of bladder cancer.     

Therapeutic potential of oncolytic measles virus: promises and challenges

Measles virus (MV) is a negative-strand RNA virus (paramyxovirus) with oncolytic properties. The significant preclinical activity of MV vaccine strains against a variety of tumor models, their potent bystander effect, their selectivity against tumor cells, and their ability to retain their oncolytic properties when engineered and retargeted makes them a promising oncolytic platform. In this article, we review potential applications and challenges associated with use of MV strains as cancer therapeutics.     

Short hairpin RNA-expressing oncolytic adenovirus-mediated inhibition of IL-8: effects on antiangiogenesis and tumor growth inhibition

RNA interference, due to its target specificity, may be highly effective as a novel therapeutic modality, but direct delivery of synthetic small interfering RNA still remains a major obstacle for this approach. To induce long-term expression and specific gene silencing, novel delivery vector system is also required. In this study, we have generated an efficient oncolytic adenovirus (Ad)-based short hairpin (shRNA) expression system (Ad-DeltaB7-U6shIL8) against IL-8, a potent proangiogenic factor. To demonstrate IL-8-specificity of this newly engineered Ad-based shRNA, we also manufactured replication-incompetent Ads (Ad-DeltaE1-CMVshIL8 and Ad-DeltaE1-U6shIL8) under the control of the cytomegalovirus (CMV) and U6 promoters, respectively. Ad-DeltaE1-U6shIL8 was highly effective in reducing IL-8 expression, and was much more effective in driving IL-8-specific shRNA than the CMV promoter-driven vector. The reduced IL-8 expression then translated into decreased angiogenesis in vitro as measured by migration, tube formation and rat aortic ring sprouting assays. In addition to its effect on endothelial cells, Ad-DeltaE1-U6shIL8 also effectively suppressed the migration and invasion of cancer cells. In vivo, intratumoral injection of Ad-DeltaB7-U6shIL8 significantly inhibited the growth of Hep3B and A549 human tumor xenografts. Histopathological analysis of Ad-DeltaB7-U6shIL8-treated tumors revealed an increase in apoptotic cells and a reduction in vessel density. Finally, Ad-DeltaB7-U6shIL8 was also shown to inhibit the growth of disseminated MDA-MB-231 breast cancer metastases. Taken together, these findings demonstrate the utility and antitumor effectiveness of oncolytic Ad expressing shRNA against IL-8.     

Protective role of Egyptian propolis against tumor in mice

BACKGROUND: Propolis has numerous biologic activities including antibiotic, antifungal, antiviral and anti-inflammatory properties. The present work is aimed to study the effect of crude Egyptian propolis on tumor in mice induced by Ehrlich ascitis carcinoma (EAC) cell line. RESULTS: The administration of propolis (160 mg/kg body weight), by gastric intubation 2 h before the intraperitoneal injection of EAC, effectively inhibited tumor growth and the proliferation of EAC. The tumor volume was markedly reduced from 7+/-0.9 ml in EAC-infected mice to 1.6+/-0.95 ml in propolis-treated mice. Also, the lipid peroxide level which was 13.3+/-1.24 nmol malodialdehyde (MDA)/mg protein in EAC infected mice was significantly decreased to 3.3+/-2.1 nmol MDA/mg protein. Reduced glutathione (GSH) and glutathione S-transferase (GST) concentrations were markedly increased in propolis-treated mice. This effect was associated with inhibition of cell cycle progression and induction of apoptosis. Administration of propolis 2 h before injection of EAC arrested cells in G0/G1 phase and resulted in a decrease in the viability, DNA, total RNA and protein level of tumor cells. CONCLUSIONS: Crude Egyptian propolis has a strong inhibitory activity against tumors. The anti-tumor mechanism may be mediated by preventing oxidative damage and induction of apoptosis.     

Generation of a recombinant Sendai virus that is selectively activated and lyses human tumor cells expressing matrix metalloproteinases

Malignant tumor cells often express matrix metalloproteinases (MMPs) at a high level to enable their dissemination and metastasis. Sendai virus (SeV), a nonsegmented negative strand RNA virus, spreads in the target tissues in vivo via cleavage activation of the viral fusion glycoprotein by a tissue-specific, trypsin-like enzyme. By deleting the viral matrix protein, we previously generated a recombinant SeV that does not bud to mature virions, but is highly fusogenic and spreads extensively from cell to cell in a trypsin-dependent manner. Here, we changed the tryptic cleavage site of the fusion glycoprotein of this virus to a site susceptible to MMPs. The resulting recombinant virus was no longer activated by trypsin but spread efficiently in cultured cells supplemented with MMP2 or MMP9 and in human tumor cell lines expressing these MMPs. Furthermore, the virus spread extensively in tumor cells xenotrasplanted to nude mice without disseminating to the surrounding normal cells, leading to the inhibition of the tumor growth in the mice. These results demonstrate the selective targeting and killing of human tumor cells by recombinant SeV technology and greatly advance the reemerging concept of oncolytic virotherapy, which currently appears to rely largely upon a natural preference of certain viruses for cancer cells.