IN-VIVO DISTRIBUTION AND GENE-EXPRESSION OF GENETICALLY-MODIFIED HEPATOCYTES AFTER INTRASPLENIC TRANSPLANTATION

To investigate the feasibility and efficacy of liver gene therapy medi ated hy intrasplenic transplantation oi genetically modified hepatocyt es, the normal mouse liver cell line BNL CL.2 cells were introduced wi th Neo-resistant (NeoR) gene or interleukin-2 (IL-2) gene in vitro, an d transplanted intrasplenically into normal sygeneic mice (2 x 10(6) c ell/mouse): subsequently, the expressions of the introduced genes in v ivo were detected. The RT-PCR results showed that NeoR mRNA expression s were detectable in livers 24 h after transplantation and lasted over 11 weeks. Moreover, The NeoR mRNA was detected to be expressed tempor arily in spleens (24 h-1 week) and lungs (24-96 h) after transplantati on. After intrasplenic transplantation of IL-2 gene-modified BNL CL.2 cells, the stable expression of IL-2 mRNA in the livers of transplante d mice were detectable by RT-PCR (24 h-11 weeks), and certain levels o f IL-2 (5-40 pg/mL) remained in the peripheral blood. When IL-2 gene-m odified BNL CL.2 cells were transplanted intrasplenically ta treat the metastatic liver colon carcinoma-bearing mice, the survival time of t he treated mice was significantly prolonged. The data indicate that in trasplenic transplantation of genetically modified hepatocytes could a llow for oriental distribution in host livers and long-term survival o f the transplanted liver cells, and effective expression of exogenous genes in vivo, suggesting that this can be a candidate approach to liv er-directed gene therapy.