In vivo gene transfer of murine interleukin-4 inhibits colon-26-mediated cancer cachexia in mice.

Cancer cachexia has been suggested to be mediated by various cytokines derived either from tumor or host tissue. In the murine colon-26 (C-26) adenocarcinoma model IL-1, secreted by tumor-infiltrating mononuclear phagocytes, has an important role in induction of cancer cachexia. In order to suppress production of IL-1 in peritoneal macrophages we have used liposome-mediated gene transfer of the anti-inflammatory cytokine mIL-4, known as a potent inhibitor of IL-1 production. Balb/c mice were transfected by intraperitoneal inoculation of C-26 tumor cells. The mIL-4 transfected animals showed increased survival rate, delayed symptoms of cachexia and reduced anorexia in comparison with tumor-bearing control groups. However, tumor growth inhibition was not seen in mIL-4-transfected animals. Peritoneal macrophages from surviving mIL-4-transfected mice, when stimulated with LPS ex vivo, showed decreased IL-1 alpha production, 1672 +/- 202 pg/2 x 10(6) cells in contrast to tumor-bearing control animals, 3975 +/- 89 pg/2 x 10(6) cells, mock-transfected tumor-bearing animals 4004 +/- 174 pg/2 x 10(6) cells and tumor-free animals, 3142 +/- 60 pg/2 x 10(6) cells (p < 0.004). The present study demonstrates that in vivo gene transfer of an anti-inflammatory cytokine reduces cancer-associated cachexia by inhibition of IL-1 alpha production of tumor surrounding peritoneal macrophages, without a significant effect on tumor growth.