title: Enhancement of rat ACT-1 tumor clonogenicity by xenogeneic mouse macrophages.
abstract: In vitro growth of rat atriocaval epithelial tumor cells (ACT-1) was enhanced by the inclusion of xenogeneic mouse adherent peritoneal exudate cells (PECs) in a two-layer soft agar system. A linear relationship was found between the number of cells plated and the number of colonies when ACT-1 tumor cells were plated at plating densities of between 1 and 5 X 10(5) cell/60 mm plate (r = 0.9, P less than 0.001). Inclusion of irradiated PECs in the bioassay for tumor stem cells resulted in a two and a half-fold increase in colony formation in three separate experiments (P less than 0.001).
mesh_terms: D000818:Animals; D002999:Clone Cells; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D009374:Neoplasms, Experimental / Q000473:pathology*; D051381:Rats; D013045:Species Specificity