Upregulation of MMPs in Metastatic Cascade of Breast Cancer To Brain

Background Brain metastasis is a lethal complication in triple negative breast cancer (TNBC) patients. Many factors including tumor cell molecular characteristics and biological environment are the main determinant in the brain metastasis process. Matrix metalloproteinases (MMPs) play a key role in extracellular matrix degradation, implicated in numerous aspects of metastasis processes of breast cancer. Methods After development of syngenic animal model of TNBC, primary breast cancer cells named 4T1T were isolated from tumor mass. Highly metastatic tumor cells named 4T1B were isolated and expanded from brain metastasis lesions of cancerous mice. Quantitative real-time polymerase chain reaction and gelatinase zymography were performed to analyze the expression of MMPs in transcriptomic and proteomic level in 4T1T and 4T1B. Results Our data revealed that, expression of MMPs was significantly upregulated in brain metastatic tumor cells. In transcriptomic level, MMP-2 and MMP-9 genes expression were up-regulated 4 and 3.4 folds in 4T1B, respectively. Zymographic analysis could be detect MMPs activity only in 4T1B. Conclusion These findings provided important insights regarding the gross alteration of MMPs expression in brain metastatic cascade of TNBC for the first time. Analysis of molecular properties of brain metastatic tumor cells can be used for understanding of molecular and genetic aspects of brain metastasis and also designing a targeted therapeutic strategies in combat with brain metastasis of TNBC.