ProAgio decreases CAFs and collagen in TNBC mouse models by inducing apoptosis in breast cancer CAFs. (A and B) Representative images of IF staining of α-SMA (A) and quantification of α-SMA⁺ area (B) in the tumors of 4T1 mice treated with vehicle or ProAgio; n = 6/group. Scale bars, 100 µm. (C and D) Representative images of IHC staining of α-SMA (C) and quantification of α-SMA⁺ area (D) in the tumors of MDA-MB-231 mice treated with vehicle or ProAgio; n = 6/group. Scale bar, 100 µm. (E and F) Representative images of Sirius red staining (E) and quantification of collagen area (F) in the tumors of 4T1 mice treated with vehicle or ProAgio; n = 7/group. Scale bars, 100 µm. (G and H) Representative images of Sirius red staining (G) and quantification of collagen area (H) in the tumors of MDA-MB-231 mice treated with vehicle or ProAgio; n = 6/group. Scale bars, 100 µm. (I–K) Representative images of IF costaining of α-SMA (red) and CC3 (green; I), quantification of apoptotic cells (CC3⁺ area; J), and apoptotic breast cancer CAFs (α-SMA⁺ CC3⁺ area; K) in tumor sections of 4T1 mice treated with vehicle or ProAgio. Nuclei were counterstained with DAPI (blue); n = 5–6/group. Scale bars, 100 µm. **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 by unpaired Student’s t test.