MDM2 and PSMA Play Inhibitory Roles in Metastatic Breast Cancer Cells Through Regulation of Matrix Metalloproteinases.

BACKGROUND/AIM: Mouse double minute 2 (MDM2) and prostate-specific membrane antigen (PSMA) are currently under investigation as individual therapeutic targets due to their overexpression in many cancer types, as well as their pro-tumorigenic effect on cells. Recently, knockdown of PSMA was linked to a decrease in MDM2 and matrix metalloproteinase 2 (MMP2) and an increase in MMP3 and MMP13 expression. We aimed to assess the link between PSMA, MDM2 and the MMPs in metastatic breast cancer cell lines.

MATERIALS AND METHODS

Real-time quantitative polymerase chain reaction (PCR) and western blotting were used to assess siRNA-mediated knockdown of MDM2 and PSMA in MDA-MB-231 and ZR-75.1 breast cancer cells. Assays to assess the growth, adhesion, migration and invasion of the cells following siRNA treatment were undertaken. MMP and tissue inhibitor of matrix metalloproteinases (TIMP) levels were assessed via quantitative PCR.

RESULTS

Knockdown of MDM2 resulted in a decrease in PSMA expression levels and vice versa; although this trend was not replicated at the protein level. Knockdown of each of the molecules resulted in a decrease in growth, adhesion, migration and invasive ability of breast cancer cells. Both knockdowns led to a decrease in MMP2 and an increase in MMP3, -10 and -13 gene expression.

CONCLUSION

MDM2 and PSMA may co-regulate the expression of certain MMPs and, thus, the functionality of cells in metastatic breast cancer.