Simvastatin induces degradation of the extracellular matrix in human leiomyomata: novel in vitro, in vivo, and patient level evidence of matrix metalloproteinase involvement

Objectives: To assess the effect of simvastatin on uterine leiomyoma growth and extracellular matrix (ECM) deposition. Design: Laboratory analysis of human leiomyoma cell culture, xenograft in a mouse model, and patient tissue from a clinical trial. Setting: Academic research center. Patient(s): Tissue culture from human leiomyoma tissue and surgical leiomyoma tissue sections from a placebo-controlled randomized clinical trial. Intervention(s): Simvastatin treatment. Main Outcome Measure(s): Serum concentrations, xenograft volumes, and protein expression. Results: Mice xenografted with 3-dimensional human leiomyoma cultures were divided as follows: 7 untreated controls; 12 treated with activated simvastatin at 10 mg/kg body weight; and 15 at 20 mg/kg body weight. Simvastatin was detected in the serum of mice injected at the highest dose. Xenograft volumes were significantly smaller (mean 53% smaller at the highest concentration). There was dissolution of compact ECM, decreased ECM formation, and lower collagen protein expression in xenografts. Membrane type 1 matrix metalloproteinase was increased in vitro and in vivo. Matrix metalloproteinase 2 and low-density lipoprotein receptor-related protein 1 were increased in vitro. Conclusions: Simvastatin exhibited antitumoral activity with ECM degradation and decreased leiomyoma tumor volume in vivo. Activation of the matrix metalloproteinase 2, membrane type 1 matrix metalloproteinase, and low-density lipoprotein receptor-related protein 1 pathway may explain these findings.