Development of new alternative in vivo models to study early metastasic dissemination in breast cancer.

SIDABRA, JOHANNA ELENA; CAPOBIANCO, CARLA SABRINA; GOTTARDO, MARÍA FLORENCIA; ALONSO, DANIEL; FARINA, HERNAN GABRIEL

Chicago

Congreso; AACR Annual Meeting 2018; 2018

AACR

Breast cancer is the first cause of death from female cancer. After treatments against the primary tumor, a few cells can prevail in a state of quiescence for a long period of time, becoming minimal residual disease. There is a clear need for alternative techniques to enable an early detection of the disease for a better understanding of it and the generation of therapies capable of acting with a smaller tumor burden. Although many models have been developed for the detection of macrometastasis, in vivo models do not allow the identification of disseminated cells, micrometastasis, or the analysis of other steps of the metastasic cascade, such as embolization or cell arrest. The aim of this work is the generation of in vivo models to enable the detection of disseminated tumor cells (DTCs)We began our study by evaluating the presence of disseminated tumor cells in three in vivo models and quantification by FACS. To this end, we generated the F3II murine triple negative mammary carcinoma line expressing the fluorescent protein GFP (F3II GFP); the F3II line was used as control. In s.c heterotopic model, we observed the presence of positive cells in tumors and livers of mice inoculated with F3II GFP (Student´s t test) 30 days post inoculation. In the s.c orthotopic model, we detected positive cells in tumors of mice inoculated with F3II GFP (Student´s t test). In both models, we did not observe significant differences in the presence of lung DTCs. In experimental metastasis models, we detected DTCs 15 days post inoculation in lungs of mice injected i.v with F3II GFP (Mann Whitney test). We carried out the search for cells disseminated at 24 h in order to obtain an in vivo model that evaluates the establishment capacity of these cells, and we observed that the percentage of GFP positive cells was higher in those mice inoculated I.v with F3II GFP (Student´s t test). In addition, the presence of DTCs was detected by fluorescence microscopy in blood smears of these mice, suggesting that at 24 h there are fluorescent tumor cells in both lung and blood. In conclusion, although the established models allowed us to detect DTCs, the experimental metastasis model was more efficient in the detection and quantification of disseminated tumor cells. These models allows the detection and quantification of DTCs in the lung and blood circulation within 24 hours and 15 days after inoculation and could be used to study the mechanisms of metastasic disemination involved in these cells and to test the capacity of various anti-tumor drugs when the load of tumor cells is low.