Fvb n female mice

Experiments on mice were conducted following Canadian Council of Animal Care (CCAC) guidelines for the care and manipulation of animals used in medical research, with approval from the Institutional Animal Protection Committee [Comité Institutionnel de Protection des Animaux (CIPA) reference number #650]. Animals used in this study were FVB/N female mice of 3–4 months of age provided by Charles River (Quebec, Canada). These mice were housed at UQAM’s animal facility under a 12 h/12 h (light/dark) cycle and they were not starved before euthanasia (ad libitum access to water and standard chow pellets). Euthanasia was performed via CO₂ inhalation, following anesthesia with isoflurane. Bowel tissues were then dissected for different experiments as described below.

Balb/c and FVB/N female mice were purchased from Charles River Laboratory. The generation and characterization of Ddr2^−/− mice has been previously described (Corsa et al., 2016 (link)). The Ddr2^−/− allele has been backcrossed onto both FVB/N and Balb/c genetic backgrounds (>10 generations). MMTV-PyMT mice were purchased from Jackson Laboratories and maintained on FVB/N background. For syngeneic orthotopic transplants, 1×10⁶ 4T1 cells (Balb/c) were injected into the fourth mammary fat pad of 8-week-old Balb/c females and allowed to reach end stage (2 cm primary tumor). Primary tumors and lungs were collected at end stage and processed for immunohistochemistry as previously described (Brenot et al., 2018 (link)). Lungs were processed in three step-sections of 50 µm steps with two serial sections of each step. Metastatic tumor nodules were counted and averaged per lobe of lung (five lobes) per mouse. Syngeneic lung colonization experiments were conducted by injecting 7.5×10⁵ PyMT-derived FVB/N tumor cells with or without 1×10⁵ CAFs (from FVB/N mice) of indicated genotypes into the tail vein of 8-week-old FVB/N female mice. After 25 days the lungs were harvested and processed as above. All animal experiments were performed according to Washington University Institutional Animal Care and Use Committee under protocol #2019-1042.

The neu exon deletion line (NDL), a syngeneic model of mammary adenocarcinoma, was obtained from the Alexander Borowsky Laboratory (UC Davis, Davis, CA). Four-week-old FVB/n female mice purchased from Charles River (Wilmington, MA) were transplanted with NDL tumor biopsies (~ 1 mm³) bilaterally into the fourth and ninth inguinal mammary fat pads. Approximately 21 days later, when tumors reached ~ 4 mm in longest dimension, mice were randomized into treatment groups.