Gene gun transfection of human glioma and melanoma cell lines with genes encoding human IL-12 and GM-CSF

We used particle-mediated gene transfer by a custom-built gene gun to trans fect two well-established human glioma (D54MG and U251) and melanoma (SK me l 28 and Ed 141) cell lines, as well as two glioma lines locally establishe d from primary patient tumors (Ed 147 and Ed 149). Using beta-galactosidase as a reporter gene, D54MG, U251, Ed 141 and SK mel 28 showed an average tr ansfection efficiency of 15-40%, whereas Ed 147 and Ed 149 had mean transfe ction efficiencies of 3% and 5% respectively. Twenty-four hours after trans fection with the gene encoding human interleukin-12 (IL-12), ELISA was perf ormed on cell supernatants (mean of n = 12 for each cell line). IL-12 expre ssion was extremely variable between the different cell lines, ranging from 52 to 1151 pg/10(6) cells/24 h. Results were very similar when cells were exposed to 20,000 rads of gamma irradiation 2 h after transfection. When th e cell lines were transfected with human granulocyte-macrophage colony-stim ulating factor, 24 h levels were: 13.0 (Ed 147), 17.8 (Ed 149), 18.6 (Ed 14 1), 27.4 (D54MG) and 27.7 ng/10(6) cells/24 h (U251). SK mel 28 produced 88 .1 ng/10(6) cells/24 h. We conclude that the gene gun can efficiently trans fect a variety of immortalized, well-established and locally-established gl ioma and melanoma cell lines. High dose gamma irradiation does not adversel y affect the expression of the foreign gene (IL-12) at 24 h. Significantly, transfected cell lines show different levels of expression depending on th e particular gene/plasmid introduced. Therefore, each cell line has to be a ssessed individually for the level of expression of each introduced gene.