MMP9 and breast cancer: In a breast cancer xenograft model (MDA-MB-231), mitochondria-targeted nanomedicines co-assembled from berberine and doxorubicin effectively repairs mitochondrial protein defects (Mfn1/Drp1) and inhibits the activity of MMP-2 and MMP-9, resulting in significant suppression of tumor cell proliferation and lung metastasis [242].