Impaired in vivo tumor growth of human pancreatic carcinoma cells retrovirally transduced with GM-CSF gene.

We have examined the antitumor effect of human pancreatic carcinoma cells (AsPC-1) retrovirally transduced with mouse granulocyte macrophage-colony stimulating factor (GM-CSF) gene in nude mice. Growth retardation of the subcutaneous tumors of GM-CSF-producing AsPC-1 cells was observed, although their in vitro proliferation was not different from that of wild-type cells. Histological examination revealed infiltration of monocytic cells into the tumor of GM-CSF-producing cells, and they were shown to be mainly CD11b positive cells by immunohistochemical staining. The survival of the mice inoculated intraperitoneally with GM-CSF- producing AsPC-1 cells was significantly prolonged compared with that of the mice inoculated with wild-type AsPC-1 cells. Thus, the expression of GM-CSF gene in human pancreatic cells induced an antitumor effect in vivo even in the mature T cell-deficient condition.