Temozolomide and Pazopanib Combined with FOLFOX Regressed a Primary Colorectal Cancer in a Patient-derived Orthotopic Xenograft Mouse Model

Purpose: The goal of the present study was to determine the efficacy of temozolomide (TEM) and pazopanib (PAZ) combined with FOLFOX (oxaliplatin, leucovorin and 5-fluorouracil) on a colorectal cancer patient-derived orthotopic xenograft (PDOX) mouse model. Materials and Methods: A colorectal cancer tumor from a patient previously established in non-transgenic nude mice was implanted subcutaneously in transgenic green fluorescence protein (GFP)-expressing nude mice in order to label the tumor stromal cells with GFP. Then labeled tumors were orthotopically implanted into the cecum of nude mice. Mice were randomized into four groups: Group 1, untreated control; group 2, TEM + PAZ; group 3, FOLFOX; group 4, TEM + PAZ plus FOLFOX. Tumor width, length, and mouse body weight were measured weekly. The Fluor Vivo imaging System was used to image the GFP-lableled tumor stromal cells in vivo. H&E staining and immunohistochemical staining were used for histological analysis. Results: All three treatments inhibited tumor growth as compared to the untreated control group. The combination of TEM + PAZ + FOLFOX regressed tumor growth significantly more effectively than TEM + PAZ or FOLFOX. Only the combination of TEM + PAZ + FOLFOX group caused a decrease in body weight. PAZ suppressed lymph vessels density in the colorectal cancer PDOX mouse model suggesting inhibition of lymphangiogenesis. Conclusion: Our results suggest that the combination of TEM + PAZ + FOLFOX has clinical potential for colorectal cancer patient.