Cytosine deaminase/5-fluorocytosine gene therapy and Apo2L/TRAIL cooperate to kill TRAIL-resistant tumor cells.

The death ligand Apo2L/TRAIL (Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand) eradicates many tumor types while sparing most normal tissues. However, some tumors are resistant to TRAIL. We therefore determined if TRAIL cooperates with cytosine deaminase/5-fluorocytosine (CD/5-FC) gene therapy and investigated the mechanisms involved.

Induction of humoral and cellular immune responses in mice by HIV-derived infectious pseudovirions.

Infectious pseudovirions based on HIV show the morphology of the parent virus and a genome that is partially expressed in infected cells. The constructs are capable of a single round of infection. In this study, we generated vesicular stomatitis virus (VSV) glycoprotein (G) pseudotyped HIV-1-derived pseudovirions that contain a codonoptimized p17/p24 HIV-1 gag or the green fluorescent protein (GFP) gene as transgene.

Human blood late outgrowth endothelial cells for gene therapy of cancer: determinants of efficacy.

Human adult blood late outgrowth endothelial cells (BOECs) are potential yet untested cellular vehicles to target tumor-cytotoxic effectors to tumors. We show that, following intravenous injection into irradiated mice, BOECs home to Lewis lung carcinoma (LLC) lung metastases, but less so to liver or kidney metastases. BOECs targeted most but not all of the lung metastases, to a different degree.

Caspase-8L expression protects CD34+ hematopoietic progenitor cells and leukemic cells from CD95-mediated apoptosis.

Regulation of sensitivity or resistance for apoptosis by death receptor ligand systems is a key control mechanism in the hematopoietic system. Dysfunctional or deregulated apoptosis can potentially contribute to the development of immune deficiencies, autoimmune diseases, and leukemia. Control of homeostasis starts at the level of hematopoietic stem cells (HSC).

Endothelial progenitor cell culture and differentiation in vitro: a methodological comparison using human umbilical cord blood.

Objective: Endothelial progenitor cells (EPC) can contribute to vascular repair and targeted tumour therapy. Little is known about generating EPC from human umbilical cord blood. We therefore compared methods for purification of EPC from human umbilical cord blood.

Foamy virus envelope glycoprotein-mediated entry involves a pH-dependent fusion process.

In general, enveloped viruses use two different entry strategies and are classified accordingly into pH-dependent and pH-independent viruses. Different members of the retrovirus family use one or the other strategy. Little is known about the uptake of foamy viruses (FV), a special group of retroviruses, into the target cells.

Improved primate foamy virus vectors and packaging constructs.

Foamy virus (FV) vectors that have minimal cis-acting sequences and are devoid of residual viral gene expression were constructed and analyzed by using a packaging system based on transient cotransfection of vector and different packaging plasmids. Previous studies indicated (i) that FV gag gene expression requires the presence of the R region of the long terminal repeat and (ii) that RNA from packaging constructs is efficiently incorporated into vector particles. Mutants with changes in major 5' splice donor (SD) site located in the R region identified this sequence element as responsible for regulating gag gene expression by an unidentified mechanism.

Phenotypic analysis of the sensitivity of HIV-1 to inhibitors of the reverse transcriptase, protease, and integrase using a self-inactivating virus vector system.

Conventional phenotypic analysis of resistance of the human immunodeficiency virus (HIV) to antiviral therapy is time-consuming and requires culture of infectious virus. Although phenotypic analyses may be desirable, rapid generation of test results and decentralized availability of the test system will be important to achieve utility in the clinical practice. This study describes the design of an alternative phenotypic resistance test using replication incompetent viral vectors.

Efficient intracellular retrotransposition of an exogenous primate retrovirus genome.

The foamy virus (FV) subgroup of Retroviridae reverse transcribe their RNA (pre-)genome late in the replication cycle before leaving an infected cell. We studied whether a marker gene-transducing FV vector is able to shuttle to the nucleus and integrate into host cell genomic DNA. While a potential intracellular retrotransposition of vectors derived from other retroviruses was below the detection limit of our assay, we found that up to 5% of cells transfected with the FV vector were stably transduced, harboring 1 to approximately 10 vector integrants.