A selective cytotoxic adenovirus vector for concentration of pluripotent stem cells in human pluripotent stem cell-derived neural progenitor cells.

Highly sensitive detection of residual undifferentiated pluripotent stem cells is essential for the quality and safety of cell-processed therapeutic products derived from human induced pluripotent stem cells (hiPSCs). We previously reported the generation of an adenovirus (Ad) vector and adeno-associated virus vectors that possess a suicide gene, inducible Caspase 9 (iCasp9), which makes it possible to sensitively detect undifferentiated hiPSCs in cultures of hiPSC-derived cardiomyocytes. In this study, we investigated whether these vectors also allow for detection of undifferentiated hiPSCs in preparations of hiPSC-derived neural progenitor cells (hiPSC-NPCs), which have been expected to treat neurological disorders. To detect undifferentiated hiPSCs, the expression of pluripotent stem cell markers was determined by immunostaining and flow cytometry. Using immortalized NPCs as a model, the Ad vector was identified to be the most efficient among the vectors tested in detecting undifferentiated hiPSCs. Moreover, we found that the Ad vector killed most hiPSC-NPCs in an iCasp9-dependent manner, enabling flow cytometry to detect undifferentiated hiPSCs intermingled at a lower concentration (0.002%) than reported previously (0.1%). These data indicate that the Ad vector selectively eliminates hiPSC-NPCs, thus allowing for sensitive detection of hiPSCs. This cytotoxic viral vector could contribute to ensuring the quality and safety of hiPSCs-NPCs for therapeutic use.

The infectivity of progeny adenovirus in the presence of neutralizing antibody.

Human adenoviruses (Ads), common pathogens that cause upper respiratory and gastrointestinal infections, are blocked by neutralizing antibodies (nAbs). However, Ads are not fully eliminated even in hosts with nAbs. In this study, we assessed the infectivity of progeny Ad serotype 5 (Ad5) in the presence of nAb. The infectivity of Ad5 was evaluated according to the expression of the Ad genome and reporter gene. Infection by wild-type Ad5 and Ad5 vector continued to increase until 3 days after infection even in the presence of nAb. We established an assay for determining the infection levels of progeny Ad5 using a sorting system with magnetic beads and observed little difference in progeny Ad5 counts in the presence and absence of nAb 1 day after infection. Moreover, progeny Ad5 in the presence of nAb more effectively infected coxsackievirus and adenovirus receptor (CAR)-positive cells than CAR-negative cells. We investigated the function of fiber proteins, which are the binding partners of CAR, during secondary infection, observing that fibre proteins spread from infected cells to adjacent cells in a CAR-dependent manner. In conclusion, this study revealed that progeny Ad5 could infect cells even in the presence of nAb, differing from the common features of the Ad5 infection cycle. Our findings may be useful for developing new therapeutic agents against Ad infection.

Expression of p57KIP2 reduces growth and invasion, and induces syncytialization in a human placental choriocarcinoma cell line, BeWo.

INTRODUCTION: Syncytiotrophoblasts are the major components of the human placenta involved in fetal maternal exchange and hormone secretion. The syncytiotrophoblasts arise from the fusion of villous cytotrophoblasts. The cell cycle suppressor p57KIP2 is known to be an essential molecule for proper trophoblast differentiation during placental formation. METHODS: We generated p57KIP2-expressing BeWo transfectant cells. Proliferation assay and matrigel invasion assay were used to characterize p57KIP2-expressing BeWo transfectant cells. To reveal the role of p57KIP2 in syncytialization, we proceeded syncytium formation analysis and qRT-PCR for detection of the expression levels Syncytin-1, Syncytin-2 and their receptors. RESULTS: The human choriocarcinoma cell line, BeWo has undetectable levels of p57KIP2 expression. Expression of p57KIP2 reduced cell proliferation rate and extracellular matrix invasion activity. p57KIP2 expressing cells displayed multinucleated cells associated with syncytiotrophoblast differentiation. In the syncytialization event, p57KIP2 was found to potentiate forskolin-induced upregulation of Syncytin-2 in a cAMP-independent manner. DISCUSSION: These results indicate that the expression of p57KIP2 may act on the proliferation/invasion inhibitory factor and enhance the expression of Syncytin-2, which are associated with syncytialization in cytotrophoblasts.

Development of Dendritic Cell-Based Immunotherapy Targeting Tumor Blood Vessels in a Mouse Model of Lung Metastasis.

Tumor blood vessels supply cancer tissues with oxygen and nutrients, and it was therefore believed that inhibition of angiogenesis would induce tumor regression. In fact, the situation is complicated by the presence of normal blood vessels in cancer tissues such as carcinomas and sarcomas as well as abnormal vessels. Here, we describe the development of a dendritic cell (DC)-based immunotherapy which targets tumor endothelial cells (TECs) rather than normal endothelial cells (ECs) or cancer cells themselves. After density gradient centrifugation, the TEC-rich fraction from lungs invaded by B16 melanoma cells was separated from the endothelial cell (EC)-rich fraction on the basis of positivity for angiotensin-converting enzyme (ACE) activity. Prophylactic vaccination with DCs pulsed with lysates of TECs isolated from lungs with metastases significantly suppressed lung metastasis in this B16/BL6 mouse melanoma model. This suggests that DC-based vaccine therapy targeting TECs in cancers tissue could show promise as an effective therapy for distant metastasis.

Cancer Vaccine Therapy Using Tumor Endothelial Cells as Antigens Suppresses Solid Tumor Growth and Metastasis.

Tumor angiogenesis plays an important role in tumor growth and metastasis, with tumor cells requiring nutrients and oxygen via blood flow for their proliferation. In comparison, angiogenesis also occurs under normal physiological conditions, such as wound healing and in the formation of the corpus luteum. Herein, we report on the development of a novel dendritic cell (DC) vaccine therapy using tumor endothelial cells (TECs) derived from tumor vessels as tumor antigens. After density gradient centrifugation and the detection of angiotensin-converting enzyme activities, a TEC-rich fraction was separated from solid tumor tissues. Prophylactic or therapeutic immunization using DCs pulsed with TECs as vaccine antigens significantly suppressed solid tumor growth in a Colon-26 colorectal adenocarcinoma tumor-bearing mouse model, compared with the use of tumor cells as DC vaccine antigens. Tumor tissues showed reduced angiogenesis. However, vaccination using DCs pulsed with TECs did not inhibit physiological angiogenesis as evidenced by a wound healing assay. Additionally, in a B16/BL6 mouse melanoma lung metastasis model, DC vaccination using TECs derived not only from the same tumor tissue but from a different type of tumor also suppressed metastasis. These results thus show that cancer vaccine therapy targeting TECs is an effective therapy against angiogenesis in several types of cancer, but does not affect normal blood vessel growth.

Identification of Adenovirus-Derived Cell-Penetrating Peptide.

Cell-penetrating peptides (CPPs) have been highly anticipated as an efficient delivery system due to their ability to cross biological membranes and transport various cargoes into cells. In the present study, we have identified adenovirus-derived CPPs using various capsid-mutant adenovirus (Ad) vectors. First, we examined the endocytosis-inducing ability of these vectors. A fiber-shaft substituted Ad vector, Ad type 5 vector with the fiber shaft domain replaced by that derived from Ad type 35, induced the highest fluorescein isothiocyanate (FITC)-dextran uptake into a human liver cell line, HepG2 cells. In contrast, the FITC-dextran uptake in HepG2 cells was not significantly different between coxsackievirus and adenovirus receptor (CAR)-binding-ablated Ad vector, integrin-binding-ablated Ad vector or conventional Ad vector. Next, we produced a recombinant Ad type 35 shaft protein using the Escherichia coli recombinant system. The recombinant Ad type 35 shaft protein retained the ability for FITC-dextran uptake and efficient gene delivery by plasmid transfection reagent. Furthermore, we identified 26 C-terminal amino acids in the Ad type 35 shaft protein as the cell membrane binding domain. The 26 amino-acid peptides also have the potential to be internalized into cultured cells. The internalization ability of the peptide was dependent on degree and was inhibited by an actin polymerization inhibitor (Latrunculin B) and by a lipid raft formation inhibitor (methyl-ß-cyclodextrin). The results of the present study indicate that Ad type 35-derived peptides induce endocytosis in cultured cells and have the ability to cross biological membranes. This report is the first paper to identify Ad-derived CPPs.

Influence of Characteristics of Oily Vehicle on Skin Penetration of Ufenamate.

Skin penetration amounts of a highly lipophilic drug, ufenamate, prepared in four oily vehicles, including white petrolatum (WP), liquid paraffin (LP), isopropyl myristate (IPM), and isocetyl stearate (ICS), were compared. Ufenamate was mixed in each vehicle at 5% and applied at a rate of 2 mg/cm2 to intact, stripped, and delipidized Yucatan micropig skin. The amounts of ufenamate and IPM in the stratum corneum (SC), epidermis, and dermis were determined. The skin penetration amounts of ufenamate from liquid oils were significantly higher than those from WP; the amounts of ufenamate were in the order WP

Suppression of murine collagen-induced arthritis by vaccination of synovial vascular endothelial cells.

AIMS: Endothelial cells (ECs) lining the lumina of blood vessels are involved in leukocyte extravasation underlying inflammatory states, such as rheumatoid arthritis (RA). The rheumatoid pannus, the site of inflammation and joint destruction in the rheumatoid synovium, relies on the development of neovascular vessels to sustain its growth. We studied a method to selectively target and destroy new synovial blood vessels by vaccination with synovial EC. MAIN METHODS: Collagen-induced arthritis (CIA) mice were vaccinated with tumor necrosis factor (TNF)-alpha-stimulated EC (TNF-EC) antigen with an incomplete adjuvant. TNF-EC was used as a model of EC in synovial tissue on RA. KEY FINDINGS: Arthritis was significantly decreased in TNF-EC vaccinated mice compared with non-vaccinated mice based on the arthritis score. Moreover, the TNF-EC vaccine suppressed bone erosion, hyperplasia of the synovium and expression of neovascular vessel as shown by hematoxylin-eosin staining, X-ray analysis and immunohistochemical. SIGNIFICANCE: Vaccine therapy against vascular EC in synovial tissue may provide a novel approach to the treatment of RA.

Prophylactic immunization with Bubble liposomes and ultrasound-treated dendritic cells provided a four-fold decrease in the frequency of melanoma lung metastasis.

Melanoma has an early tendency to metastasize, and the majority of the resulting deaths are caused by metastatic melanoma. It is therefore important to develop effective therapies for metastasis. Dendritic cell (DC)-based cancer immunotherapy has been proposed as an effective therapeutic strategy for metastasis and recurrence due to prime tumor-specific cytotoxic T lymphocytes. In this therapy, it is important that DCs present peptides derived from tumor-associated antigens on MHC class I molecules. Previously, we developed an innovative approach capable of directly delivering exogenous antigens into the cytosol of DCs using perfluoropropane gas-entrapping liposomes (Bubble liposomes, BLs) and ultrasound. In the present study, we investigated the prevention of melanoma lung metastasis via DC-based immunotherapy. Specifically, antigens were extracted from melanoma cells and used to treat DCs by BL and ultrasound. Delivery into the DCs by this route did not require the endocytic pathway. The delivery efficiency was approximately 74.1%. DCs treated with melanoma-derived antigens were assessed for in vivo efficacy in a mouse model of lung metastasis. Prophylactic immunization with BL/ultrasound-treated DCs provided a four-fold decrease in the frequency of melanoma lung metastases. These in vitro and in vivo results demonstrate that the combination of BLs and ultrasound is a promising method for antigen delivery system into DCs.

Progress in the development of ultrasound-mediated gene delivery systems utilizing nano- and microbubbles.

Recently, ultrasound-mediated gene delivery with nano- and microbubbles was developed as a novel non-viral vector system. In this gene delivery system, microstreams and microjets, which are induced by disruption of nano/microbubbles exposed to ultrasound, are used as the driving force to transfer genes into cells by opening transient pores in the cell membrane. This system can directly deliver plasmid DNA and siRNA into cytosol without endocytosis pathway. Therefore, these genes are able to escape from degradation in lysosome and result in enhancing the efficiency of gene expression. In addition, it is expected that ultrasound-mediated gene delivery using nano/microbubbles would be a system to establish non-invasive and tissue specific gene expression because ultrasound can transdermally expose to target tissues and organs. This review focuses on the current ultrasound-mediated gene delivery system using nano/microbubbles. We discuss about the feasibility of this gene delivery system as novel non-viral vector system.

In vitro approaches to evaluate placental drug transport by using differentiating JEG-3 human choriocarcinoma cells.

Human choriocarcinoma cells have been used as models for studying transcellular drug transport through placental trophoblasts. However, these models allow the transport of low-molecular-weight drugs through intercellular gap junctions. This study aimed at investigating the differentiation patterns of JEG-3 choriocarcinoma cells under different culture conditions and establishing the appropriate model of in vitro syncytiotrophoblast drug transport. Paracellular permeability was estimated by measuring the transepithelial electrical resistance (TEER) across JEG-3 cell layers. The mRNA expression levels of non-expressed in choriocarcinoma clone 1 (NECC1) and breast cancer resistance protein (BCRP), and those of E-cadherin (ECAD) and cadherin-11 (CDH11), which are adherens junction-associated proteins related to fusogenic ability of syncytiotrophoblasts differentiated from cytotrophoblasts, protein expression levels were considered as the differentiation signals. The highest TEER values were obtained in the JEG-3 cells cultured in the Dulbecco's modified Eagle's medium (DMEM)/Ham's F-12 (1:1) mixed medium (CS-C(®) ; Dainippon Sumitomo Pharma Co. Ltd., Osaka, Japan). By comparing the TEER values and the differentiation signals, the authors identified at least five JEG-3 cell-differentiation patterns. The differentiation pattern of JEG-3 cultured in CS-C resembled the syncytiotrophoblast-like differentiation signal characterizations in vivo. In conclusion, the syncytiotrophoblast-like models of differentiating JEG-3 cells cultured in CS-C might be appropriate for evaluating drug transport across the placental trophoblast.

[Development of ultrasonic cancer therapy using ultrasound sensitive liposome].

Ultrasound (US) has been utilized as a useful tool for diagnosis and therapy. US mediated drug and gene delivery is paid to attention as a non-invasive system. The combination of US and microbubbles generated microjet stream by inducing disruption of bubbles and resulted in enhancing permeability of cell membrane. This phenomenon has been utilized as driving force for drug and gene delivery. Recently, we developed ultrasound sensitive liposome [Bubble liposome (BL)] containing perfluoropropane gas. US combined with BL could effectively transfer gene in vivo compared to conventional cationic liposomes. Using this method, we succeeded to obtain a therapeutic effect in cancer gene therapy with Interleukin-12 corded plasmid DNA. Therefore, it is expected that US combined with BL might be a useful non-viral vector system. From this result, the fusion of liposomal and ultrasound technologies would be important for establishment of advanced cancer therapy.

Circadian rhythm of transferrin receptor 1 gene expression controlled by c-Myc in colon cancer-bearing mice.

The abundance of cell surface levels of transferrin receptor 1 (TfR1), which regulates the uptake of iron-bound transferring, correlates with the rate of cell proliferation. Because TfR1 expression is higher in cancer cells than in normal cells, it offers a target for cancer therapy. In this study, we found that the expression of TfR1 in mouse colon cancer cells was affected by the circadian organization of the molecular clock. The core circadian oscillator is composed of an autoregulatory transcription-translation feedback loop, in which CLOCK and BMAL1 are positive regulators and the Period (Per), Cryptochrome (Cry), and Dec genes act as negative regulators. TfR1 in colon cancer-bearing mice exhibited a 24-hour rhythm in mRNA and protein levels. Luciferase reporter analysis and chromatin immunoprecipitation experiments suggested that the clock-controlled gene c-MYC rhythmically activated the transcription of the TfR1 gene. Platinum incorporation into tumor DNA and the antitumor efficacy of transferrin-conjugated liposome-delivered oxaliplatin could be enhanced by drug administration at times when TfR1 expression increased. Our findings suggest that the 24-hour rhythm of TfR1 expression may form an important aspect of strategies for TfR1-targeted cancer therapy.

[Development of anti-tumor blood vessel antibodies by phage display method].

Tumor blood vessels are essential for tumor growth. Therefore, these blood vessels are potential targets for anti-cancer therapy. The purpose of this study is to develop anti-tumor endothelial cell (TEC) antibodies for delivering anti-cancer agents or drugs. To achieve this goal, we utilized the phage antibody display library method to create monoclonal antibodies in vitro. Accordingly, we developed anti-TEC antibodies from an single chain Fv fragment (scFv) phage display library prepared using the Fv genes amplified from the mRNAs isolated from the TEC-immunized mice. The size of the phage antibody library prepared from the mRNA of the TEC-immunized mice was approximately 1.3x10(7) CFU. To select and enrich for the phages displaying the anti-TEC antibodies, cell panning was performed first using the TEC followed by subtractive panning using the normal endothelial cell. After five cycles of panning, the affinity of bound phage clones increased approximately 10 000 folds. Subsequently, clones isolated from the post-panning output library were tested for their antigen-specificity by ELISA and western blotting. One of the scFv phage clones showing antigen-specificity recognized only TEC in vitro, and when injected into the Colon26 bearing mice, this clone accumulated more on the tumor tissue than the wild type phage. These results suggest that the isolated an antibody and this clone's target molecule could be potentially useful for novel anti-tumor therapies.

Cancer gene therapy by IL-12 gene delivery using liposomal bubbles and tumoral ultrasound exposure.

Interleukin-12 (IL-12) gene therapy is expected to be effective against cancers because it primes the immune system for cancer cells. In this therapy, it is important to induce IL-12 gene expression in the tumor tissue. Sonoporation is an attractive technique for developing non-invasive and non-viral gene delivery systems, but simple sonoporation using only ultrasound is not an effective cancer gene therapy because of the low efficiency of gene delivery. We addressed this problem by combining ultrasound and novel ultrasound-sensitive liposomes (Bubble liposomes) which contain the ultrasound imaging gas perfluoropropane. Our previous work showed that this is an effective gene delivery system, and that Bubble liposome collapse (cavitation) is induced by ultrasound exposure. In this study, we assessed the utility of this system in cancer gene therapy using IL-12 corded plasmid DNA. The combination of Bubble liposomes and ultrasound dramatically suppressed tumor growth. This therapeutic effect was T-cell dependent, requiring mainly CD8(+) T lymphocytes in the effector phase, as confirmed by a mouse in vivo depletion assay. In addition, migration of CD8(+) T cells was observed in the mice, indicating that the combination of Bubble liposomes and ultrasound is a good non-viral vector system in IL-12 cancer gene therapy.

A novel strategy utilizing ultrasound for antigen delivery in dendritic cell-based cancer immunotherapy.

In dendritic cell (DC)-based cancer immunotherapy, it is important that DCs present peptides derived from tumor-associated antigens on MHC class I, and activate tumor-specific cytotoxic T lymphocytes (CTLs). However, MHC class I generally present endogenous antigens expressed in the cytosol. We therefore developed an innovative approach capable of directly delivering exogenous antigens into the cytosol of DCs; i.e., a MHC class I-presenting pathway. In this study, we investigated the effect of antigen delivery using perfluoropropane gas-entrapping liposomes (Bubble liposomes, BLs) and ultrasound (US) exposure on MHC class I presentation levels in DCs, as well as the feasibility of using this antigen delivery system in DC-based cancer immunotherapy. DCs were treated with ovalbumin (OVA) as a model antigen, BLs and US exposure. OVA was directly delivered into the cytosol but not via the endocytosis pathway, and OVA-derived peptides were presented on MHC class I. This result indicates that exogenous antigens can be recognized as endogenous antigens when delivered into the cytosol. Immunization with DCs treated with OVA, BLs and US exposure efficiently induced OVA-specific CTLs and resulted in the complete rejection of E.G7-OVA tumors. These data indicate that the combination of BLs and US exposure is a promising antigen delivery system in DC-based cancer immunotherapy.

[Development of site specific gene delivery system with sonoporation].

In gene therapy, it is important to develop an effective and safe gene delivery system. Especially, from the viewpoint of reducing side effects, gene delivery into a specific site is essential. We previously, developed liposomal bubbles (Bubble liposomes) containing perfluoropropane. Bubble liposomes were useful as ultrasound enhanced gene delivery tools in vitro and in vivo. In this review, we introduced the characteristics of Bubble liposomes as ultrasound imaging agents and ultrasound enhanced gene delivery tools. Bubble liposomes worked as ultrasound imaging agents in cardiosonography. In addition, their combination with ultrasound exposure was able to deliver plasmid DNA in the femoral artery. The gene expression was only observed at the site of ultrasound exposure. Moreover, the gene delivery by Bubble liposomes and ultrasound exposure was more efficient than that by conventional lipofection method using Lipofectamine 2000. Therefore, it was suggested that Bubble liposomes might be a new class of tools for site specific gene delivery.

Effective gene delivery with novel liposomal bubbles and ultrasonic destruction technology.

From the viewpoint of safety, non-viral vector systems represent an attractive gene delivery system for gene therapy. However, the transfection efficiency of non-viral vectors in vivo is generally very low. Previously, it was reported that microbubbles, utilized as imaging agents for diagnostic echocardiography, could promote gene delivery into cells when combined with ultrasound exposure. We therefore developed novel liposomal bubbles (Bubble liposomes) containing the lipid nanobubbles of perfluoropropane which is used as ultrasound imaging agent. These Bubble liposomes were smaller in diameter than conventional microbubbles and induced cavitation upon exposure to ultrasound. These results suggested that cavitation of these Bubble liposomes could be an efficient approach for delivering plasmid DNA into cells. In addition, in in vivo gene delivery, the combination of Bubble liposomes and ultrasound provided more effective gene delivery than conventional lipofection methods, further suggesting that Bubble liposomes could be effective as a non-viral vector system in in vivo gene delivery. In this review, we discuss the characteristics of Bubble liposomes and their potential utility as a gene delivery tool in vitro and in vivo.

Tumor specific ultrasound enhanced gene transfer in vivo with novel liposomal bubbles.

Bubble liposomes (liposomes which entrap an ultrasound imaging gas) may constitute a unique system for delivering various molecules efficiently into mammalian cells in vitro. In this study, Bubble liposomes were compared with cationic lipid (CL)-DNA complexes as potential gene delivery carriers into tumor in vivo. The delivery of genes by Bubble liposomes depended on the intensity of the applied ultrasound. Transfection efficiency plateaued at 0.7 W/cm(2) ultrasound intensity. Bubble liposomes efficiently transferred genes into cultured cells even when the cells were exposed to ultrasound for only 1 s. In addition, Bubble liposomes could introduce the luciferase gene more effectively than CL-DNA complexes into mouse ascites tumor cells and solid tumor tissue. We conclude that the combination of Bubble liposomes and ultrasound is a minimally-invasive and tumor specific gene transfer method in vivo.