Figure 3. Cyclophosphamide (CTX) suppresses tumor growth in both orthotopic and subcutaneous CDX models. (A) Schematic of the experimental design for tumor cells implantation and CTX treatment. (B) Images and weight of dissected tumors from primary orthotopic (n = 3) and subcutaneous (n = 4) xenograft mice. The tumors were then digested and inoculated into NCG mice to construct the secondary orthotopic or subcutaneous CDX mice as indicated. (C) Survival curves of secondary orthotopic CDX mice which were implanted with tumor cells from primary orthotopic (Orth→Orth) or subcutaneous (Subq→Orth) CDX mice were treated with CTX or saline (control) (n = 5). (D) The average counts of bioluminescence signals of tumors in the secondary Orth→Orth (n = 4) and Subq→Orth (n = 3) CDX mice treated with or without CTX were measured at indicated time points. (E) In vivo tumor growth was monitored at the indicated time points in (C) (n = 5). (F) Survival curves of secondary Orth→Subq and Subq→Subq CDX mice treated with or without CTX (n = 5). Data are presented as the mean ± SEM. *P < 0.05; **P < 0.01; ****P < 0.0001.