Boric acid (BA), an essential plant micronutrient, has recently been discovered as a chemo-preventive agent in prostate cancer; however, its mechanism of action remains unknown. Our interest is to determine if BA has a preventative role in breast cancer and elucidate its possible mechanism. Integrins are transmembrane proteins responsible for cell growth, survival and adhesion. We hypothesize that BA interacts with integrins to mediate its response. To test this hypothesis we used BA and phenylboronic acid (PBA), a bulkier analog of BA, on breast ductal carcinoma, ZR-75-1, and breast andenocarcinoma, MCF-7; BA and PBA treatments were tested through proliferation, cytotoxicity and cell cycle analysis experiments. These preliminary results show that BA and PBA effectively inhibit growth in both breast cancer cell lines through dose-dependent cell cycle block and apoptosis. Adhesion and integrin activity assays did not definitively identify which integrins are affected by BA and PBA treatments
