Fig. 3From: The anti-neoplastic effect of doxycycline in osteosarcoma as a metalloproteinase (MMP) inhibitor: a systematic reviewMechanism of MMPs inactivation by Doxycycline. Osteosarcoma cells secrete MMPs which support survival and invasiveness of malignant cells. Doxycycline (DOX) inactivates MMPs by forming chelation bonds with their Zn2+ and Ca2+ ions [7]Back to article page