Adenovirus expressing nc886, an anti-interferon and anti-apoptotic non-coding RNA, is an improved gene delivery vector.

Recombinant adenovirus (rAdV) vector is the most promising vehicle to deliver an exogenous gene into target cells and is preferred for gene therapy. Exogenous gene expression from rAdV is often too inefficient to induce phenotypic changes and the amount of administered rAdV must be very high to achieve a therapeutic dose. However, it is often hampered because a high dose of rAdV is likely to induce cytotoxicity by activating immune responses. nc886, a 102-nucleotide non-coding RNA that is transcribed by RNA polymerase III, acts as an immune suppressor and a facilitator of AdV entry into the nucleus. Therefore, in this study, we have constructed an rAdV expressing nc886 (AdV:nc886) to explore whether AdV:nc886 overcomes the aforementioned drawbacks of conventional rAdV vectors. When infected into mouse cell lines and mice, AdV:nc886 expresses a sufficient amount of nc886, which suppresses the induction of interferon-stimulated genes and apoptotic pathways triggered by AdV infection. As a result, AdV:nc886 is less cytotoxic and produces more rAdV-delivered gene products, compared with the parental rAdV vector lacking nc886. In conclusion, this study demonstrates that the nc886-expressing rAdV could become a superior gene delivery vehicle with greater safety and higher efficiency for in vivo gene therapy.

Complexation of drug and hapten-conjugated aptamer with universal hapten antibody for pancreatic cancer treatment.

Owing to a lack of reliable markers and therapeutic targets, pancreatic ductal adenocarcinoma (PDAC) remains the most lethal malignant tumor despite numerous therapeutic advances. In this study, we utilized cell-SELEX to isolate a DNA aptamer recognizing the natural conformation of the target on the cell surface. PAp7T8, an aptamer optimized by size and chemical modification, exhibited specific targeting to pancreatic cancer cells and orthotopic xenograft pancreatic tumors. To confer therapeutic functions to the aptamer, we adopted a drug-conjugated oligobody (DOligobody) strategy. Monomethyl auristatin E was used as a cytotoxic drug, digoxigenin acted as a hapten, and the humanized anti-digoxigenin antibody served as a universal carrier of the aptamer. The resulting PAp7T8-DOligobody showed extended in vivo half-life and markedly inhibited tumor growth in an orthotopic pancreatic cancer xenograft model without causing significant toxicity. Therefore, PAp7T8-DOligobody represents a promising novel therapeutic delivery platform for PDAC.

A host non-coding RNA, nc886, plays a pro-viral role by promoting virus trafficking to the nucleus.

Elucidation of the interplay between viruses and host cells is crucial for taming viruses to benefit human health. Cancer therapy using adenovirus, called oncolytic virotherapy, is a promising treatment option but is not robust in all patients. In addition, inefficient replication of human adenovirus in mouse hampered the development of an in vivo model for preclinical evaluation of therapeutically engineered adenovirus. nc886 is a human non-coding RNA that suppresses Protein Kinase R (PKR), an antiviral protein. In this study, we have found that nc886 greatly promotes adenoviral gene expression and replication. Remarkably, the stimulatory effect of nc886 is not dependent on its function to inhibit PKR. Rather, nc886 facilitates the nuclear entry of adenovirus via modulating the kinesin pathway. nc886 is not conserved in mouse and, when xenogeneically expressed in mouse cells, promotes adenovirus replication. Our investigation has discovered a novel mechanism of how a host ncRNA plays a pro-adenoviral role. Given that nc886 expression is silenced in a subset of cancer cells, our study highlights that oncolytic virotherapy might be inefficient in those cells. Furthermore, our findings open future possibilities of harnessing nc886 to improve the efficacy of oncolytic adenovirus and to construct nc886-expressing transgenic mice as an animal model.

Nc886, a Novel Suppressor of the Type I Interferon Response Upon Pathogen Intrusion.

Interferons (IFNs) are a crucial component in the innate immune response. Especially the IFN-ß signaling operates in most cell types and plays a key role in the first line of defense upon pathogen intrusion. The induction of IFN-ß should be tightly controlled, because its hyperactivation can lead to tissue damage or autoimmune diseases. Activation of the IFN-ß promoter needs Interferon Regulatory Factor 3 (IRF3), together with Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Activator Protein 1 (AP-1). Here we report that a human noncoding RNA, nc886, is a novel suppressor for the IFN-ß signaling and inflammation. Upon treatment with several pathogen-associated molecular patterns and viruses, nc886 suppresses the activation of IRF3 and also inhibits NF-κB and AP-1 via inhibiting Protein Kinase R (PKR). These events lead to decreased expression of IFN-ß and resultantly IFN-stimulated genes. nc886's role might be to restrict the IFN-ß signaling from hyperactivation. Since nc886 expression is regulated by epigenetic and environmental factors, nc886 might explain why innate immune responses to pathogens are variable depending on biological settings.

Therapeutic Application of Drug-Conjugated HER2 Oligobody (HER2-DOligobody).

Antibody drug conjugates (ADCs), consisting of a cancer-specific antibody and cytotoxic payload, are shown to be a potent class of anticancer therapeutics, with enhanced therapeutic efficacy and reduced "off-target" side effects. However, the therapeutic window of ADCs is narrowed by problems such as difficulty in site-specific conjugation of payload, changes in antibody stability due to payload conjugation, and difficulty in tissue penetration. In this respect, aptamers have advantages in drug-delivery, as they can be easily and stably conjugated with cytotoxic drugs. We previously reported that oligobody, an aptamer-antibody complex, is a novel delivery method for aptamer-based therapeutics. In the current study, we describe DOligobody, a drug-conjugated oligobody comprising an aptamer-drug conjugate and an antibody. A cotinine-conjugated anti-HER2 aptamer (cot-HER2apt) was specifically bound to HER2-positive NCI-N87 cells, and underwent receptor-mediated endocytosis. Further, HER2-DOligobody, a cot-HER2apt-conjugated monomethyl auristatin E (cot-HER2apt-MMAE) oligobody, inhibited the growth of HER2-positive NCI-N87 cells. Finally, systemic administration of HER2-DOligobody significantly reduced tumor growth in a xenograft mouse model. Taken together, these results suggest that our DOligobody strategy may be a powerful platform for rapid, low-cost and effective cancer therapy.

A Regulatory Noncoding RNA, nc886, Suppresses Esophageal Cancer by Inhibiting the AKT Pathway and Cell Cycle Progression.

nc886 is a regulatory non-coding RNA (ncRNA) whose expression is frequently silenced in malignancies. In the case of esophageal squamous cell carcinoma (ESCC), nc886 silencing is associated with shorter survival of patients, suggesting nc886's tumor suppressor role in ESCC. However, this observation has not been complemented by an in-detail study about nc886's impact on gene expression and cellular phenotypes. Here we have shown that nc886 inhibits AKT, a key protein in a renowned pro-survival pathway in cancer. nc886-silenced cells (nc886- cells) have activated AKT and altered expression of cell cycle genes. nc886- cells tend to have lower expression of CDKN2A and CDKN2C, both of which are inhibitors for cyclin-dependent kinase (CDK), and higher expression of CDK4 than nc886-expressing cells. As a result, nc886- cells are hyperactive in the progression of the G1 to S cell cycle phase, proliferate faster, and are more sensitive to palbociclib, which is a cancer therapeutic drug that targets CDK4/6. Experimentally by nc886 expression and knockdown, we have determined the AKT target genes and cell cycle genes that are controlled by nc886 (nc886-associated gene sets). These gene sets, in combination with pathologic staging and nc886 expression levels, are a vastly superior predictor for the survival of 108 ESCC patients. In summary, our study has elucidated in ESCC how nc886 inhibits cell proliferation to explain its tumor suppressor role and identified gene sets that are of future clinical utility, by predicting patient survival and responsiveness to a therapeutic drug.

Mechanism mediated by a noncoding RNA, nc886, in the cytotoxicity of a DNA-reactive compound.

DNA-reactive compounds are harnessed for cancer chemotherapy. Their genotoxic effects are considered to be the main mechanism for the cytotoxicity to date. Because this mechanism preferentially affects actively proliferating cells, it is postulated that the cytotoxicity is specific to cancer cells. Nonetheless, they do harm normal quiescent cells, suggesting that there are other cytotoxic mechanisms to be uncovered. By employing doxorubicin as a representative DNA-reactive compound, we have discovered a cytotoxic mechanism that involves a cellular noncoding RNA (ncRNA) nc886 and protein kinase R (PKR) that is a proapoptotic protein. nc886 is transcribed by RNA polymerase III (Pol III), binds to PKR, and prevents it from aberrant activation in most normal cells. We have shown here that doxorubicin evicts Pol III from DNA and, thereby, shuts down nc886 transcription. Consequently, the instantaneous depletion of nc886 provokes PKR and leads to apoptosis. In a short-pulse treatment of doxorubicin, these events are the main cause of cytotoxicity preceding the DNA damage response in a 3D culture system as well as the monolayer cultures. By identifying nc886 as a molecular signal for PKR to sense doxorubicin, we have provided an explanation for the conundrum why DNA-damaging drugs can be cytotoxic to quiescent cells that have the competent nc886/PKR pathway.

Phase I trial of intravenous Ad5CRT in patients with liver metastasis of gastrointestinal cancers.

We conducted a phase 1 trial for single-dose intravenous Ad5CRT, a replication-defective adenovirus vector expressing HSVtk (herpes simplex virus thymidine kinase) modulated by a specific trans-splicing ribozyme that targets human telomerase reverse transcriptase (hTERT)-encoding RNAs. Dose-limiting toxicities (DLTs) were evaluated in 15 patients at dose levels of 0.1-2 × 1012 virus particles. Patients well tolerated study treatment. During the DLT evaluation period, none of the 15 patients developed any grade 4 toxicities or treatment discontinuation that was related to agents investigated by this trial. The most frequent treatment-related adverse event was fever/chill (26.7%). Of the 18 patients, no patients achieved a partial or complete response, and the median progression-free survival for 18 patients was 1.1 months (95% CI, 1.0-1.3) and the results suggest no clinical benefit from this treatment. Ad5CRT's circulating virus half-life was approximately 10 min. Maximum tolerated dose was 2 × 1012 virus particles. Single-dose intravenous Ad5CRT was feasible and well tolerated in patients with gastrointestinal cancer liver metastasis. Ad5CRT did not provide meaningful clinical benefit, and the reason for the lack of efficacy was not entirely clear because no pharmocodynamic assessment was made.

Increased prevalence of metabolic syndrome in adult cancer survivors: Asian first report in community setting.

BACKGROUND: To compare the prevalence of metabolic syndrome (MeS) in cancer survivors returning to the community to that of non-cancer controls. METHODS: We used baseline data from a nationwide cohort study. 5274 cancer survivors and 20,703 and 21,096 gender- and age-matched controls without and with chronic disease was included. RESULTS: The prevalence of MeS was higher in cancer survivors compared to controls without chronic disease, but was lower than that in controls with chronic disease (25.7%, 18.8%, and 32.0%, respectively). The prevalence was 1.56-fold higher in cancer survivors (95% confidence interval = 1.45-1.69) than in controls without chronic disease. The prevalence of each MeS component was significantly higher in cancer survivors compared to controls without chronic disease. Compared to controls, the prevalence was higher in colorectal, breast, cervical, lung, thyroid, prostate, and bladder cancer survivors (OR range = 1.63-2.24, P-value < 0.05), but not in gastric and liver cancer survivors. CONCLUSIONS: MeS was generally more prevalent among cancer survivors than in controls without chronic disease, but with heterogeneities in cancer type. Because long-term care and comorbidity prevention are emerging issues in cancer survivors, MeS among those returning to normal life is concerning, and tailored management programs should be developed for specific cancer types.

Depletion of MOB1A/B causes intestinal epithelial degeneration by suppressing Wnt activity and activating BMP/TGF-ß signaling.

The Hippo pathway is involved in intestinal epithelial homeostasis with Wnt, BMP, Notch, and EGF signaling. We investigated the relationship between Hippo and other signaling pathways and the role of MOB kinase activator 1A/1B (MOB1A/B) in intestinal homeostasis. Mice with intestinal epithelial cell (IEC)-specific depletion of MOB1A/B showed hyperproliferation in IECs, defects in secretory lineage differentiation and loss of intestinal stem cells and eventually died at 10-12 days after tamoxifen treatment. In MOB1A/B-depleted IECs, expression of Wnt target genes were downregulated but Bmp2 and Tgfbr2 were transcriptionally activated with enhanced YAP activity. In in vivo and in vitro experiments with several signaling inhibitors, it has been shown that the BMP inhibitor LDN193189 or TGF-ß inhibitor SB431542 had effects on partial restoration of the intestinal degenerative phenotype. Treatment with these inhibitors restored differentiation of secretory lineage cells in MOB1A/B-deficient mice, but not ISC pools in the crypt region. These studies reveal that IEC-specific depletion of MOB1A/B induced overexpression of Bmp2 and Tgfbr2 and inhibited Wnt activity, finally leading to loss of ISCs and functional epithelia in the mouse intestine. These results suggest that MOB1A/B has an essential function for intestinal epithelial homeostasis by regulating YAP, Wnt activity, and BMP/TGF-ß signaling.

Dynamic relocalization of NHERF1 mediates chemotactic migration of ovarian cancer cells toward lysophosphatidic acid stimulation.

NHERF1/EBP50 (Na+/H+ exchanger regulating factor 1; Ezrin-binding phosphoprotein of 50 kDa) organizes stable protein complexes beneath the apical membrane of polar epithelial cells. By contrast, in cancer cells without any fixed polarity, NHERF1 often localizes in the cytoplasm. The regulation of cytoplasmic NHERF1 and its role in cancer progression remain unclear. In this study, we found that, upon lysophosphatidic acid (LPA) stimulation, cytoplasmic NHERF1 rapidly translocated to the plasma membrane, and subsequently to cortical protrusion structures, of ovarian cancer cells. This movement depended on direct binding of NHERF1 to C-terminally phosphorylated ERM proteins (cpERMs). Moreover, NHERF1 depletion downregulated cpERMs and further impaired cpERM-dependent remodeling of the cell cortex, suggesting reciprocal regulation between these proteins. The LPA-induced protein complex was highly enriched in migratory pseudopodia, whose formation was impaired by overexpression of NHERF1 truncation mutants. Consistent with this, NHERF1 depletion in various types of cancer cells abolished chemotactic cell migration toward a LPA gradient. Taken together, our findings suggest that the high dynamics of cytosolic NHERF1 provide cancer cells with a means of controlling chemotactic migration. This capacity is likely to be essential for ovarian cancer progression in tumor microenvironments containing LPA.

Preclinical development of a humanized neutralizing antibody targeting HGF.

Hepatocyte growth factor (HGF) and its receptor, cMET, play critical roles in cell proliferation, angiogenesis and invasion in a wide variety of cancers. We therefore examined the anti-tumor activity of the humanized monoclonal anti-HGF antibody, YYB-101, in nude mice bearing human glioblastoma xenografts as a single agent or in combination with temozolomide. HGF neutralization, The extracellular signal-related kinases 1 and 2 (ERK1/2) phosphorylation, and HGF-induced scattering were assessed in HGF-expressing cell lines treated with YYB-101. To support clinical development, we also evaluated the preclinical pharmacokinetics and toxicokinetics in cynomolgus monkeys, and human and cynomolgus monkey tissue was stained with YYB-101 to test tissue cross-reactivity. We found that YYB-101 inhibited cMET activation in vitro and suppressed tumor growth in the orthotopic mouse model of human glioblastoma. Combination treatment with YYB-101 and temozolomide decreased tumor growth and increased overall survival compared with the effects of either agent alone. Five cancer-related genes (TMEM119, FST, RSPO3, ROS1 and NBL1) were overexpressed in YYB-101-treated mice that showed tumor regrowth. In the tissue cross-reactivity assay, critical cross-reactivity was not observed. The terminal elimination half-life was 21.7 days. Taken together, the in vitro and in vivo data demonstrated the anti-tumor efficacy of YYB-101, which appeared to be mediated by blocking the HGF/cMET interaction. The preclinical pharmacokinetics, toxicokinetics and tissue cross-reactivity data support the clinical development of YYB-101 for advanced cancer.

Epigenetic regulation of noncoding RNA transcription by mammalian RNA polymerase III.

RNA polymerase III (Pol III) synthesizes a range of medium-sized noncoding RNAs (collectively 'Pol III genes') whose early established biological roles were so essential that they were considered 'housekeeping genes'. Besides these fundamental functions, diverse unconventional roles of mammalian Pol III genes have recently been recognized and their expression must be exquisitely controlled. In this review, we summarize the epigenetic regulation of Pol III genes by chromatin structure, histone modification and CpG DNA methylation. We also recapitulate the association between dysregulation of Pol III genes and diseases such as cancer and neurological disorders. Additionally, we will discuss why in-depth molecular studies of Pol III genes have not been attempted and how nc886, a Pol III gene, may resolve this issue.

Histone variant H3F3A promotes lung cancer cell migration through intronic regulation.

Although several somatic single nucleotide variations in histone H3.3 have been investigated as cancer drivers, other types of aberration have not been well studied. Here, we demonstrate that overexpression of H3F3A, encoding H3.3, is associated with lung cancer progression and promotes lung cancer cell migration by activating metastasis-related genes. H3.3 globally activates gene expression through the occupation of intronic regions in lung cancer cells. Moreover, H3.3 binding regions show characteristics of regulatory DNA elements. We show that H3.3 is deposited at a specific intronic region of GPR87, where it modifies the chromatin status and directly activates GPR87 transcription. The expression levels of H3F3A and GPR87, either alone or in combination, are robust prognostic markers for early-stage lung cancer, and may indicate potential for the development of treatments involving GPR87 antagonists. In summary, our results demonstrate that intronic regulation by H3F3A may be a target for the development of novel therapeutic strategies.

Oncogenic function and clinical implications of SLC3A2-NRG1 fusion in invasive mucinous adenocarcinoma of the lung.

The neuregulin 1 (NRG1) fusion is a recently identified novel driver oncogene in invasive mucinous adenocarcinoma of the lung (IMA). After identification of a case of SLC3A2-NRG1 in a patient with IMA, we verified this fusion gene in a cohort of 59 patients with IMA. Targeted cancer panel sequencing and RT-PCR identified the possible coexistence of other driver oncogenes. Among 59 IMAs, we found 16 NRG1 fusions (13 SLC3A2-NRG1 and 3 CD74-NRG1). Of 16 patients with NRG1 fusions, concurrent KRAS codon 12 mutations were found in 10 cases. We also found concurrent NRAS Q61L mutation and EML4-ALK fusion in additional two cases with NRG1 fusions. When comparing overall survival (OS) according to the presence of NRG1 fusions showed that patients harboring NRG1 fusions had significantly inferior OS than those without NRG1 fusions (hazard ratio = 0.286; 95% confidence interval, .094 to .865). Ectopic expression of the SLC3A2-NRG1 fusion in lung cancer cells increased cell migration, proliferation and tumor growth in vitro and in xenograft models, suggesting oncogenic function for the fusion protein. We found that the SLC3A2-NRG1 fusion promoted ERBB2-ERBB3 phosphorylation and heteroduplex formation and activated the downstream PI3K/AKT/mTOR pathway through paracrine signaling. These findings suggested that the SLC3A2-NRG1 fusion was a driver in IMA with an important prognostic impact. SLC3A2-NRG1 should be considered a therapeutic target for patients with IMA.

nc886, a non-coding RNA and suppressor of PKR, exerts an oncogenic function in thyroid cancer.

nc886 is a recently identified cellular non-coding RNA and its depletion leads to acute cell death via PKR (Protein Kinase RNA-activated) activation. nc886 expression is increased in some malignancies, but silenced in others. However, the precise role of nc886/PKR is controversial: is it a tumor suppressor or an oncogene? In this study, we have clarified the role of nc886 in thyroid cancer by sequentially generating PKR knockout (KO) and PKR/nc886 double KO cell lines from Nthy-ori 3-1, a partially transformed thyroid cell line. Compared to the wildtype, PKR KO alone does not exhibit any significant phenotypic changes. However, nc886 KO cells are less proliferative, migratory, and invasive than their parental PKR KO cells. Importantly, the requirement of nc886 in tumor phenotypes is totally independent of PKR. In our microarray data, nc886 KO suppresses some genes whose elevated expression is associated with poor survival confirmed by data from total of 505 thyroid cancer patients in the Caner Genome Atlas project. Also, the nc886 expression level tends to be elevated and in more aggressively metastatic tumor specimens from thyroid cancer patients. In summary, we have discovered nc886's tumor-promoting role in thyroid cancer which has been concealed by the PKR-mediated acute cell death.

An aptamer-antibody complex (oligobody) as a novel delivery platform for targeted cancer therapies.

Aptamers have recently emerged as reliable and promising targeting agents in the field of biology. However, their therapeutic potential has yet to be completely assessed due to their poor pharmacokinetics for systemic administration. Here, we describe a novel aptamer-antibody complex, designated an "oligobody" (oligomer+antibody) that may overcome the therapeutic limitations of aptamers. To provide proof-of-principle study, we investigated the druggability of oligobody in vivo using cotinine conjugated t44-OMe aptamer, which is specific for the sequence of pegaptanib, and an anti-cotinine antibody. The antibody part of oligobody resulted in extended in vivo pharmacokinetics of the aptamer without influencing its binding affinity. Moreover, the aptamer of oligobody penetrated deeply into the tumor tissues whereas the anti-VEGF antibody did not. Finally, the systemic administration of this oligobody reduced the tumor burden in a xenograft mouse model. Together, these results suggested that our oligobody strategy may represent a novel platform for rapid, low-cost and high-throughput cancer therapy.

Image-aided Suicide Gene Therapy Utilizing Multifunctional hTERT-targeting Adenovirus for Clinical Translation in Hepatocellular Carcinoma.

Trans-splicing ribozyme enables to sense and reprogram target RNA into therapeutic transgene and thereby becomes a good sensing device for detection of cancer cells, judging from transgene expression. Previously we proposed PEPCK-Rz-HSVtk (PRT), hTERT targeting trans-splicing ribozyme (Rz) driven by liver-specific promoter phosphoenolpyruvate carboxykinase (PEPCK) with downstream suicide gene, herpes simplex virus thymidine kinase (HSVtk) for hepatocellular carcinoma (HCC) gene therapy. Here, we describe success of a re-engineered adenoviral vector harboring PRT in obtaining greater antitumor activity with less off-target effect for clinical application as a theranostics. We introduced liver-selective apolipoprotein E (ApoE) enhancer to the distal region of PRT unit to augment activity and liver selectivity of PEPCK promoter, and achieved better transduction into liver cancer cells by replacement of serotype 35 fiber knob on additional E4orf1-4 deletion of E1&E3-deleted serotype 5 back bone. We demonstrated that our refined adenovirus harboring PEPCK/ApoE-Rz-HSVtk (Ad-PRT-E) achieved great anti-tumor efficacy and improved ability to specifically target HCC without damaging normal hepatocytes. We also showed noninvasive imaging modalities were successfully employed to monitor both how well a therapeutic gene (HSVtk) was expressed inside tumor and how effectively a gene therapy took an action in terms of tumor growth. Collectively, this study suggests that the advanced therapeutic adenoviruses Ad-PRT-E and its image-aided evaluation system may lead to the powerful strategy for successful clinical translation and the development of clinical protocols for HCC therapy.

Distinctive responses of brain tumor cells to TLR2 ligands.

Malignant brain tumor mass contains significant numbers of infiltrating glial cells that may intimately interact with tumor cells and influence cancer treatments. Understanding of characteristic discrepancies between normal GLIA and tumor cells would, therefore, be valuable for improving anticancer therapeutics. Here, we report distinct differences in toll-like receptors (TLR)-2-mediated responses between normal glia and primary brain tumor cell lines. We found that tyrosine phosphorylation of STAT1 by TLR2 ligands and its downstream events did not occur in mouse, rat, or human brain tumor cell lines, but were markedly induced in normal primary microglia and astrocytes. Using TLR2-deficient, interferon (IFN)-γ-deficient, and IFNγ-receptor-1-deficient mice, we revealed that the impaired phosphorylation of STAT1 might be linked with defective TLR2 system in tumor cells, and that a TLR2-dependent pathway, not IFNγ-receptor machinery, might be critical for tyrosine STAT1 phosphorylation by TLR2 ligands. We also found that TLR2 and its heterodimeric partners, TLR1 and 6, on brain tumor cells failed to properly respond to TLR2 ligands, and representative TLR2-dependent cellular events, such as inflammatory responses and cell death, were not detected in brain tumor cells. Similar results were obtained in in vitro and in vivo experiments using orthotopic mouse and rat brain tumor models. Collectively, these results suggest that primary brain tumor cells may exhibit a distinctive dysfunction of TLR2-associated responses, resulting in abnormal signaling and cellular events. Careful targeting of this distinctive property could serve as the basis for effective therapeutic approaches against primary brain tumors.

Development of replication-competent adenovirus for bladder cancer by controlling adenovirus E1a and E4 gene expression with the survivin promoter.

Survivin is a member of the inhibitors of apoptosis protein family. Here, we examined survivin expression and confirmed abundant survivin expression in bladder cancer cells. This expression pattern indicated that the transcriptional regulatory elements that control survivin expression could be utilized to discriminate cancer from normal cells. We therefore generated a novel adenovirus termed Ad5/35E1apsurvivinE4 with the following characteristics: 1) E1A and E4 protein expression was dependent on survivin promoter activity; 2) the green fluorescence protein gene was inserted into the genome under the control of the CMV promoter; 3) most of the E3 sequences were deleted, but the construct was still capable of expressing the adenovirus death protein with potent cytotoxic effects; and 4) the fiber knob was from serotype 35 adenovirus. As expected from the abundant survivin expression observed in bladder cancer cells, Ad5/35E1apsurvivinE4 replicated better in cancer cells than in normal cells by a factor of 106 to 102. Likewise, Ad5/35E1apsurvivinE4 exerted greater cytotoxic effects on all bladder cancer cell lines tested. Importantly, Ad5/35E1apsurvivinE4 inhibited the growth of Ku7-Luc orthotopic xenografts in nude mice. Taken together, Ad5/35E1apsurvivinE4 indicates that the survivin promoter may be utilized for the development of a replication-competent adenovirus to target bladder cancers.