Abstract

The Bowman‐Birk inhibitor (BBI) is a soybean‐derived anticarcinogenic protease inhibitor with anti‐inflammatory activity. To assess the possibility of utilizing BBI for alleviating the side effects associated with lung cancer radiation and chemotherapy, we have determined the effects of BBI and a soybean concentrate enriched in BBI (known as BBIC) on radiation‐ and cis‐platinum‐induced cytotoxicity in A549 human lung cancer cells. The results demonstrated that neither BBI nor BBIC protected A549 cells from radiation‐ and cis‐platinum‐induced cytotoxicity. In fact, BBI and BBIC potentiated the cell‐killing effects induced by cis‐platinum alone, and BBIC treatment led to significantly enhanced cell killing by cis‐platinum in combination with radiation treatment in the lung carcinoma cells. BBI conferred a significant protective effect onto mouse fibroblasts (10T1/2 cells) treated with cis‐platinum in combination with 6 Gy of X‐ray irradiation. These results suggest that BBI and BBIC, when given to lung cancer patients, are unlikely to interfere with cancer treatment utilizing radiation and cis‐platinum.