The development of new viral vectors will focus on more efficient transduction and expression and on cell-type specific expression. Recombinant vectors containing mutant forms of herpes simplex thymidine kinase that are less toxic will be constructed and tested in vitro in combination with ganciclovir and novel antiherpetic nucleoside analogues. Vectors expressing the E. coli DeoD gene will be engineered and tested in combination with 6-methyl-purine-2'-deoxynucleoside. After studying the therapeutic index and bystander effect of these novel suicide gene/prodrug combinations in vitro, application in selected animal models will take place.
Different routes of non-traumatic and more efficient viral vector delivery will be developed including systemic administration, convection enhanced intratumoral delivery and retrovirus producing cells embedded in biopolymers. These methods will be tested partly in vitro but mostly in a variety of animal models.
In vivo imaging of the efficiency of suicide gene transfer is based on selective accumulation of some nucleoside analogues (including 5-iodo-2'-fluoro-2'-deoxy-arabinofuranosyluracil [FIAU]), after phosphorylation by herpes simplex thymidine kinase. Radiolabeled (14C, 125I, 18F) nucleoside analogues (FIAU) will first be tested in vitro using autoradiography and subsequently in vivo using autoradiography and SPECT/PET imaging.
The bystander effect will be studied in vitro (above) and in vivo in brain tumour and multiple myeloma, Iymphoma and seminoma models. Modulation of the bystander effect will be attempted in vitro and in the multiple myeloma model by upregulation of connexins, molecules involved in gapjunction formation. The anti-tumor immune response elicited by suicide gene/prodrug treatment will be analyzed and modulated by cytokine (GM-CSF and IFNy) gene transfer.
Funding SchemeCSC - Cost-sharing contracts
3075 EA Rotterdam
141 57 Huddinge
M13 9PT Manchester