Figure 4. SDS3 inhibits experimental lung metastases from circulating, MMP9-producing VO-PyMT metastatic cells.

(A) Left: qPCR of Mmp9 levels in VO-PyMT-GFP-Luc cells and the normal mammary cell lines EpH4 and NMuMG. Right: gel zymography of indicated cell lines demonstrating MMP9 activity. (B) Schematic of experimental setup: 1 × 10⁶ VO-PyMT-GFP-Luc cells along with IgG isotype control or SDS3 was i.v. injected into WT mice. Subsequently, the antibodies were i.p. injected every other day for eight times before the mice were euthanized. Weekly bioluminescence imaging was performed to monitor the growth of the i.v.–injected tumor cells. (C) Left: bioluminescent imaging of 9-wk-old WT mice 3 wk after i.v. injection of VO-PyMT-GFP-Luc probing cells. Middle: representative fluorescent whole lung images of WT mice treated with SDS3 or IgG after a 3-wk chase. Right: quantification of the lung metastatic burden in WT mice treated with SDS3 or IgG (n = 9 IgG, n = 9 SDS3). (D) Quantification of in situ zymography of lungs in WT mice treated with SDS3 or IgG (n = 3 each).