Modeling and Integral X-Ray, Optical, and MRI Visualization of Multiorgan Metastases of Orthotopic 4T1 Breast Carcinoma in BALB/c Mice

, No. 4, pp. 268-275, October, 2014Original article submitted October 7, 2014A model of highly metastasizing orthotopic allogeneic breast carcinoma was reproduced and standardized in experiments on BALB/c mice. 4T1 cells characterized by high metastatic activity were transfected with red fl uorescent protein (RFP) gene or fi refl y luciferase (Luc2) gene. Unmodifi ed 4T1 cells and modifi ed 4T1-RFP and 4T1-Luc2 cells were subcutaneously injected to mature female mice into the second mammary fat pads. Quantitative evaluation of the primary node and visceral metastases was performed using magnetic-resonance imag-ing, X-ray and optical tomography. Modifi cation of 4T1 cells with RFP gene considerably reduced their invasive and metastatic potential and led to spontaneous regression of the primary tumor in 20% cases. Modifi cation of 4T1 cells with Luc2 gene had practically no effect on proliferative, invasive, and metastatic characteristics of the tumor and provided the possibility of quantitative analysis of the primary tumor dynamics by the luminescence intensity. The survival median in mice receiving unmodifi ed 4T1 cells and transfected 4T1-RFP and 4Т1-Luc2 cells was 32, 42, and 38 days, respectively. Neither primary node nor tumor metastases accumulated gadolinium-containing contrast agent and Alasens fl uorescent tracer. After implantation of 4T1 and 4Т1-Luc2 cells, multiple metastases were more often detected in the lungs, liver, spleen, spine, and regional lymph nodes and less frequently in the brain, which corresponded to metastasizing profi le of human breast cancer. The devel-oped model of orthotopic breast carcinoma 4T1 in BALB/c mice with complex detection of multiple organ metastases using X-ray microCT, optical, and MRI can be recommended for preclinical studies of new antitumor preparations.