Therapeutic efficacy of an oncolytic adenovirus containing RGD ligand in minor capsid protein IX and Fiber, Δ24DoubleRGD, in an ovarian cancer model

Ovarian cancer is the leading cause of gynecological disease death despite advances in medicine. Therefore, novel strategies are required for ovarian cancer therapy. Conditionally replicative adenoviruses (CRAds), genetically modified as anti-cancer therapeutics, are one of the most attractive candidate agents for cancer therapy. However, a paucity of coxsackie B virus and adenovirus receptor (CAR) expression on the surface of ovarian cancer cells has impeded treatment of ovarian cancer using this approach.This study sought to engineer a CRAd with enhanced oncolytic ability in ovarian cancer cells, “Δ24DoubleRGD.” Δ24DoubleRGD carries an arginine-glycine-aspartate (RGD) motif incorporated into both fiber and capsid protein IX (pIX) and its oncolytic efficacy was evaluated in ovarian cancer. In vitro analysis of cell viability showed that infection of ovarian cancer cells with Δ24DoubleRGD leads to increased cell killing relative to the control CRAds. Data from this study suggested that not only an increase in number of RGD motifs on the CRAd capsid, but also a change in the repertoir of targeted integrins could lead to enhanced oncolytic potency of Δ24DoubleRGD in ovarian cancer cells in vitro. In an intraperitoneal model of ovarian cancer, mice injected with Δ24DoubleRGD showed, however, a similar survival rate as mice treated with control CRAds

U4 snRNA nucleolar localization requires the NHPX/15.5-kD protein binding site but not Sm protein or U6 snRNA association

All small nuclear RNAs (snRNAs) of the [U4/U6.U5] tri-snRNP localize transiently to nucleoli, as visualized by microscopy after injection of fluorescein-labeled transcripts into Xenopus laevis oocyte nuclei. Here, we demonstrate that these RNAs traffic to nucleoli independently of one another, because U4 snRNA deleted in the U6 base-pairing region still localizes to nucleoli. Furthermore, depletion of endogenous U6 snRNA does not affect nucleolar localization of injected U4 or U5. The wild-type U4 transcripts used here are functional: they exhibit normal nucleocytoplasmic traffic, associate with Sm proteins, form the [U4/U6] di-snRNP, and localize to nucleoli and Cajal bodies. The nucleolar localization element (NoLE) of U4 snRNA was mapped by mutagenesis. Neither the 5′-cap nor the 3′-region of U4, which includes the Sm protein binding site, are essential for nucleolar localization. The only region in U4 snRNA required for nucleolar localization is the 5′-proximal stem loop, which contains the binding site for the NHPX/15.5-kD protein. Even mutation of just five nucleotides, essential for binding this protein, impaired U4 nucleolar localization. Intriguingly, the NHPX/15.5-kD protein also binds the nucleolar localization element of box C/D small nucleolar RNAs, suggesting that this protein might mediate nucleolar localization of several small RNAs

Astrocytes promote progression of breast cancer metastases to the brain via a KISS1-mediated autophagy.

Formation of metastases, also known as cancer dissemination, is an important stage of breast cancer (BrCa) development. KISS1 expression is associated with inhibition of metastases development. Recently we have demonstrated that BrCa metastases to the brain exhibit low levels of KISS1 expression at both mRNA and protein levels. By using multicolor immunofluorescence and coculture techniques here we show that normal adult astrocytes in the brain are capable of promoting metastatic transformation of circulating breast cancer cells localized to the brain through secretion of chemokine CXCL12. The latter was found in this study to downregulate KISS1 expression at the post-transcriptional level via induction of microRNA-345 (MIR345). Furthermore, we demonstrated that ectopic expression of KISS1 downregulates ATG5 and ATG7, 2 key modulators of autophagy, and works concurrently with autophagy inhibitors, thereby implicating autophagy in the mechanism of KISS1-mediated BrCa metastatic transformation. We also found that expression of KISS1 in human breast tumor specimens inversely correlates with that of MMP9 and IL8, implicated in the mechanism of metastatic invasion, thereby supporting the role of KISS1 as a potential regulator of BrCa metastatic invasion in the brain. This conclusion is further supported by the ability of KISS1, ectopically overexpressed from an adenoviral vector in MDA-MB-231Br cells with silenced expression of the endogenous gene, to revert invasive phenotype of those cells. Taken together, our results strongly suggest that human adult astrocytes can promote brain invasion of the brain-localized circulating breast cancer cells by upregulating autophagy signaling pathways via the CXCL12-MIR345- KISS1 axis

Adenovirus Gene Transfer to Amelogenesis Imperfecta Ameloblast-Like Cells

To explore gene therapy strategies for amelogenesis imperfecta (AI), a human ameloblast-like cell population was established from third molars of an AI-affected patient. These cells were characterized by expression of cytokeratin 14, major enamel proteins and alkaline phosphatase staining. Suboptimal transduction of the ameloblast-like cells by an adenovirus type 5 (Ad5) vector was consistent with lower levels of the coxsackie-and-adenovirus receptor (CAR) on those cells relative to CAR-positive A549 cells. To overcome CAR -deficiency, we evaluated capsid-modified Ad5 vectors with various genetic capsid modifications including “pK7” and/or “RGD” motif-containing short peptides incorporated in the capsid protein fiber as well as fiber chimera with the Ad serotype 3 (Ad3) fiber “knob” domain. All fiber modifications provided an augmented transduction of AI-ameloblasts, revealed following vector dose normalization in A549 cells with a superior effect (up to 404-fold) of pK7/RGD double modification. This robust infectivity enhancement occurred through vector binding to both αvβ3/αvβ5 integrins and heparan sulfate proteoglycans (HSPGs) highly expressed by AI-ameloblasts as revealed by gene transfer blocking experiments. This work thus not only pioneers establishment of human AI ameloblast-like cell population as a model for in vitro studies but also reveals an optimal infectivity-enhancement strategy for a potential Ad5 vector-mediated gene therapy for AI

HIV Antigen Incorporation within Adenovirus Hexon Hypervariable 2 for a Novel HIV Vaccine Approach

Adenoviral (Ad) vectors have been used for a variety of vaccine applications including cancer and infectious diseases. Traditionally, Ad-based vaccines are designed to express antigens through transgene expression of a given antigen. However, in some cases these conventional Ad-based vaccines have had sub-optimal clinical results. These sub-optimal results are attributed in part to pre-existing Ad serotype 5 (Ad5) immunity. In order to circumvent the need for antigen expression via transgene incorporation, the “antigen capsid-incorporation” strategy has been developed and used for Ad-based vaccine development in the context of a few diseases. This strategy embodies the incorporation of antigenic peptides within the capsid structure of viral vectors. The major capsid protein hexon has been utilized for these capsid incorporation strategies due to hexon's natural role in the generation of anti-Ad immune response and its numerical representation within the Ad virion. Using this strategy, we have developed the means to incorporate heterologous peptide epitopes specifically within the major surface-exposed domains of the Ad capsid protein hexon. Our study herein focuses on generation of multivalent vaccine vectors presenting HIV antigens within the Ad capsid protein hexon, as well as expressing an HIV antigen as a transgene. These novel vectors utilize HVR2 as an incorporation site for a twenty-four amino acid region of the HIV membrane proximal ectodomain region (MPER), derived from HIV glycoprotein gp41 (gp41). Our study herein illustrates that our multivalent anti-HIV vectors elicit a cellular anti-HIV response. Furthermore, vaccinations with these vectors, which present HIV antigens at HVR2, elicit a HIV epitope-specific humoral immune response

Xenopus U3 snoRNA docks on pre-rRNA through a novel base-pairing interaction

U3 small nucleolar RNA (snoRNA) is essential for rRNA processing to form 18S ribosomal RNA (rRNA). Previously, it has been shown that nucleolin is needed to load U3 snoRNA on pre-rRNA. However, as documented here, this is not sufficient. We present data that base-pairing between the U3 hinges and the external transcribed spacer (ETS) is critical for functional alignment of U3 on its pre-rRNA substrate. Additionally, the interaction between the U3 hinges and the ETS is proposed to serve as an anchor to hold U3 on the pre-rRNA substrate, while box A at the 5′ end of U3 snoRNA swivels from ETS contacts to 18S rRNA contacts. Compensatory base changes revealed base-pairing between the 3′ hinge of U3 snoRNA and region E1 of the ETS in Xenopus pre-rRNA; this novel interaction is required for 18S rRNA production. In contrast, base-pairing between the 5′ hinge of U3 snoRNA and region E2 of the ETS is auxiliary, unlike the case in yeast where it is required. Thus, higher and lower eukaryotes use different interactions for functional association of U3 with pre-rRNA. The U3 hinge sequence varies between species, but covariation in the ETS retains complementarity. This species-specific U3-pre-rRNA interaction offers a potential target for a new class of antibiotics to prevent ribosome biogenesis in eukaryotic pathogens

Molecular Imaging of Gene Therapy

Molecular imaging techniques that emerged in biology as a means to monitor intracellular trafficking and interaction of macromolecules have lately become a powerful tool also for detection of transgene delivery by viral vectors. The necessity of monitoring and quantification of vectordelivered transgene expression prompted development of new generation viral vectors. Those encoded a special class of reporter genes whose expression in vector-targeted cells and tissues allowed quantitative assessment of vectormediated gene transfer and thereby a noninvasive real-time tracking of the viral vectors at the tissue and the whole-body levels. Those imaging reporters are classified in this review according to their biochemical nature, type of the generated imaging signal, substrate requirements, and type of tracer/substrate used for signal generation. This chapter reviews imaging strategies, used for adenoviral vectors, as a major class of gene therapy vectors, as well as other (nonadenoviral) common virus-based vector systems. Special attention is given to imaging strategies, used to monitor replicative vectors for oncolytic therapy applications. One of those is a new approach of genetic capsid labeling that potentially allows for direct monitoring of the viral progeny particles, as opposed to reporter transgene expression, typically used in vector imaging. The major advancements in imaging vector development are reviewed in the context of their applications for research and clinical purposes.Fil: Lopez, Maria Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Matthews, Qiana L.. No especifíca;Fil: Curiel, David T.. No especifíca;Fil: Borovjagin, Anton v.. No especifíca