Cationic lipid gene transfer of an IL-2 transgene leads to activation of natural killer cells in a SCID mouse human tumor xenograft.
Natural killer (NK) cells play an important role in combating infectious and malignant diseases and interleukin-2 (IL-2) has been shown to promote proliferation and activation of NK cells in vitro and in vivo. Here we investigate the effects of local cationic lipid-mediated IL-2 gene transfer on intratumoral accumulation and activation of NK cells in a SCID mouse tumor model. UM449 human melanoma tumors in SCID mice received intratumoral injections of DMRIE/DOPE admixed with VR1103, a DNA plasmid encoding the gene for human IL-2. Dissagregated tumor cells were tested for IL-2 secretion and were characterized using antibodies to asGM1, MAC-1, and F4/80 antigens. Granzyme A, a proteolytic serine esterase, was also measured in tumor cell lysates. IL-2 secretion from tumors injected with VR1103:DMRIE/DOPE peaked at 48 h after injection and fell to baseline levels on day 8. Intratumoral granzyme A activity was significantly increased in tumors injected with IL-2 plasmid:DMRIE/DOPE complexes, but not by an irrelevant plasmid DNA:DMRIE/DOPE control. Importantly, the growth of UM449 tumors was slowed in VR1103:DMRIE/DOPE-injected tumors. These results indicate that local cationic lipid-mediated gene transfer of IL-2 induces activation of intratumoral NK cells and slows tumor growth.
Clark
P R
PR
Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724, USA.
Stopeck
A T
AT
Parker
S E
SE
Hersh
E M
EM
D000818:Animals; D002412:Cations; D002634:Chemotaxis, Leukocyte; D003602:Cytotoxicity, Immunologic; D018014:Gene Transfer Techniques; D053804:Granzymes; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics; D007694:Killer Cells, Natural / Q000276:immunology*; D008055:Lipids; D016131:Lymphocyte Subsets / Q000276:immunology*; D008545:Melanoma / Q000276:immunology*; D051379:Mice; D016513:Mice, SCID; D012697:Serine Endopeptidases / Q000096:biosynthesis; D019076:Transgenes; D014183:Transplantation, Heterologous
D002412:Cations; D007376:Interleukin-2; D008055:Lipids; D053804:Granzymes; D012697:Serine Endopeptidases; C509212:GZMA protein, human