Antitumor effect of soybean lectin mediated through reactive oxygen species-dependent pathway

Aims: The present study evaluated the potential role of soybean lectin's (SBL) anticancer effect in vitro in different cancer cell lines and the therapeutic effectiveness in vivo in Dalton's lymphoma (DL) bearing mice model. Main methods: The effect of SBL on cell growth and viability was measured using MTT assay in different cancer cells in vitro. Apoptosis, autophagic cell death, DNA-damaging potential and reactive oxygen species (ROS) were analyzed in HeLa cells. The in vivo efficacy of SBL was demonstrated in Dalton's lymphoma (DL) bearing mice. Key findings: SBL demonstrated clear, strong antiproliferative activity without affecting normal cells; however, heat denaturation of SBL diminished the antiproliferative efficacy of molecule as demonstrated by MTT assay. A sharp 74.51 +/- 3.5% and 82.95 +/- 5.8% inhibition of tumor cell proliferation in DL mice occurred when SBL was administered at a dosage of 1 and 2 mg/kg body weight (i.p.), respectively, for ten days with the induction of autophagic and apoptotic cell death. An in vitro investigation revealed that SBL-mediated autophagy, apoptosis and DNA damage in HeLa cells were inflicted through the generation of ROS in a dose-dependent manner. Interestingly, pre-treating HeLa cells with N-acetylcysteine (NAC), a typical ROS scavenger, led to a noticeable reduction in SBL-induced autophagy, apoptosis and DNA-damaging activities, suggesting that SBL's antitumor potential was governed by ROS activation. Significance: In this study, we evaluated the apoptotic, autophagic death, and DNA-damaging effects of SBL in cancer cells, which may have the potential to be used as a phyto-derived protein for cancer therapy. (C) 2014 Elsevier Inc. All rights reserved.