Doxycycline hydrochloride, an antibiotic, is an orally active and broad-spectrum metalloproteinase (MMP) inhibitor[1].
Doxycycline hydrochloride affects growth of glioma cells only under high concentrations[2]. Doxycycline hydrochloride decreases MT-CO1 protein content with concentrations of 1 µg/mL and higher in SVG cells[2].
Doxycycline hydrochloride (oral; 200 or 800 mg/kg/day; for 3 months) reduces active MMP-9 in untreated HT mice in a dose-dependent manner[1]
References:
[1]. Wilfried Briest, et al. Doxycycline ameliorates the susceptibility to aortic lesions in a mouse model for the vascular type of Ehlers-Danlos syndrome. J Pharmacol Exp Ther. 2011 Jun;337(3):621-7.
[2]. Luger AL, et al. Doxycycline Impairs Mitochondrial Function and Protects Human Glioma Cells from Hypoxia-Induced Cell Death: Implications of Using Tet-Inducible Systems. Int J Mol Sci. 2018 May 17;19(5).