Synergistic anti-tumor effect of glycosylphosphatidylinositol-anchored IL-2 and IL-12.
BACKGROUND
Preclinical and clinical studies have demonstrated that interleukin 2 (IL-2), interleukin 12 (IL-12), and some other cytokines, play important roles in activating host immune responses against tumor growth. However, severe side effects caused by systemic high-dose administration of these cytokines limit their clinical application. In our previous study, local high doses of IL-2 were achieved by a GPI-anchoring technology; therefore, it will be interesting to know if this technology works for other cytokines.


METHODS
A fusion gene containing murine IL-12 and the glycosylphosphatidylinositol (GPI) anchor signal sequence was generated and transfected into the murine melanoma tumor cell line B16F0 either alone or together with a vector encoding GPI-anchored IL-2. The GPI-anchored cytokine expression of the selected stable clones was assayed in vitro by ELISA and their anti-tumor effects were analyzed in vivo by tumor lymphocyte infiltration and tumor growth studies.


RESULTS
GPI-anchored IL-12 was successfully expressed on the cell surface as indicated by FACS analysis and IL-12 ELISA assay. The GPI-anchored IL-12 enhanced lymphocyte infiltration and significantly inhibited tumor growth. More importantly, when GPI-anchored IL-12 and GPI-anchored IL-2 were co-delivered, a synergistic anti-tumor effect was observed in both subcutaneous and intravenous tumor models.


CONCLUSIONS
GPI anchorage of cytokines represents a new approach to locally deliver high doses of cytokines without the severe adverse effects normally accompanied with systematic high-dose administration of these cytokines.
Ji
Jianfei
J
Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA.
Li
Jinhua
J
Holmes
Lillia M
LM
Burgin
Kelly E
KE
Yu
Xianzhong
X
Wagner
Thomas E
TE
Wei
Yanzhang
Y
D000818:Animals; D002455:Cell Division / Q000276:immunology; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D018664:Interleukin-12 / Q000378:metabolism*; D007376:Interleukin-2 / Q000378:metabolism*; D016246:Lymphocytes, Tumor-Infiltrating / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000276:immunology / Q000473:pathology / Q000628:therapy*
D017261:Glycosylphosphatidylinositols; D007376:Interleukin-2; D018664:Interleukin-12