RNA Interference of IQ Motif Containing GTPase-Activating Protein 3 (IQGAP3) Inhibits Cell Proliferation and Invasion in Breast Carcinoma Cells.

Breast cancer is a highly prevalent disease affecting women. The association of IQ motif containing GTPase-activating protein 3 (IQGAP3) and breast cancer is poorly defined. Here we reported that IQGAP3 is a key regulator of cell proliferation and metastasis during breast cancer progression. The expression of IQGAP3 was significantly increased in breast tissues compared to nontumor tissues at both protein and mRNA levels. Furthermore, IQGAP3 had a high expression level in ZR-75-30 and BT474 compared to other breast cancer cell lines. Depletion of IQGAP3 through RNA interference in ZR-75-30 and BT474 significantly inhibited cell proliferation. More importantly, IQGAP3 silencing in breast cancer cells notably repressed cell migration and invasion. Further analysis suggested that inhibition of cell proliferation and metastasis was associated with some proteins, including p53, MMP9, Snail, CDC42, p-ERK1/2, KIF2C, KIF4A, PCNA, and Twist. Since expression of IQGAP3 seems to be associated with the pathogenesis of breast cancer and suppression of it can inhibit cancer cell growth and metastasis, IQGAP3 may be a potential therapeutic target in human breast cancer.