Fig. 2

Changes in pulmonary elastin and metalloproteinase expression in 4T1 breast cancer progression in mice. Paraffin-embedded lungs cut into slices to visualize elastin (see Methods). a–f above Representative image of (a) healthy control and 1st (b), 2nd (c), 3rd (d), 4th (e), and 5th (f) week after 4T1 cancer cell inoculation. Scale bar represents 50 μm. a–f below Corresponding segmentation. g Differences in relative elastin expression (dark gray pixels corresponding to elastin vs light gray pictures corresponding to lung tissue), shown as mean ± SD. Black circle indicates outlier; n = 20 for healthy control mice and mice in 1st, 2nd, and 4th week of disease; n = 21 for mice in 3rd week of disease; n = 19 for mice in 5th week of disease. Data subjected to Box–Cox transformation and analyzed by one-way AVOVA followed by Tukey’s multiple comparison test due to normality of distribution and homogeneity of variances. Statistical difference vs healthy control mice at *P < 0.05 and ***P < 0.001. h MMP-2, MMP-9, and MMP-14 expression in pooled samples (n = 6) (see Methods). MMP-2, higher band indicates inactive isoform while lower band indicates active isoform. MMP-14, higher band corresponds to active monomer while lower band corresponds to domains after catalytical cleavage. Results presented as fold change vs control sample corresponding to healthy mice. Total protein after transfer was used as loading control