CA4P improves survival of mice that underwent xenotransplantation with human leukemia cells. NOD-SCID mice were intravenously inoculated with GFP⁺ HL60 cells and 3 days after injection, mice were treated every other day with intraperitoneal injection of CA4P (25 mg/kg) or PBS (control). (A) CA4P prolongs survival of xenotransplanted mice. Survival of mice treated with CA4P was enhanced compared with the control mice (P < .05; n = 5). (B) CA4P decreases leukemic cell circulation in the peripheral blood and engraftment in the bone marrow, spleen, liver, and lung. At 30 days after xenotransplantation of GFP⁺ HL60 cell injection, the presence of GFP⁺ HL60 cells in the peripheral blood and the different tissues of the mice was assessed by quantification of double positive GFP and human CD45 cells by flow cytometry. (C) CA4P decreases organ-specific leukemic cell infiltration. On day 30 after inoculation of GFP⁺ HL60 cells, CA4P-treated mice showed evidence of minor foci of leukemic infiltrates in the liver, but had no evidence of invading leukemic cells in the lung and the spleen. In contrast, control mice had considerable tumor infiltrates in the spleen, liver, and lung. Original magnification, 40×. Scale bar equals 50 μm; percentages in graphs are percent positive cells.