The toxicity mechanism of glabridin in prostate cancer cells is involved in reactive oxygen species‐dependent PI3K/Akt pathway: Integrated utilization of bioinformatic analysis and in vitro test validation

Abstract Glabridin is a prenylated isoflavonoid with considerable anticancer property. Reactive oxygen species (ROS) have evolved as regulators of many cellular signaling pathways in prostate cancer (PC). However, the role of ROS signaling in the anticancer activity of glabridin has not been investigated. Here, we attempted to evaluate the effect of glabridin on PC and the involvement of ROS signaling. Intracellular ROS and mitochondrial ROS (mitoROS) production in PC cell lines, DU‐145 and LNCaP, were measured by H2DCFDA and MitoSOX Red staining, respectively. MTT assay was used to analyze the cellular viability. EdU staining assay was conducted to analyze the cell proliferation. To analyze apoptotic rate, TUNEL assay was performed. Caspase‐3 activity was detected to reflect cell apoptosis. Western blot was carried out to detect the expression levels of Akt and p‐Akt. We found that intracellular ROS and mitoROS levels were dose‐dependently upregulated after glabridin treatment in both DU‐145 and LNCaP cells, which was reversed by the treatment of ROS inhibitor, N ‐acetyl‐L‐cysteine (NAC). Glabridin inhibited the cell viability and reduced the number of EdU‐positive DU‐145 and LNCaP cells, which were respectively proved by MTT assay and EdU staining assay. Glabridin promoted cell death with increased apoptotic rate and caspase‐3 activity in DU‐145 and LNCaP cells. The effects of glabridin on cell proliferation and apoptosis were reversed by NAC. Moreover, glabridin suppressed the ratio of p‐Akt/Akt, while NAC mitigated the decreased p‐Akt/Akt ratio. In addition, the effects of glabridin on cell proliferation and apoptosis were also attenuated by Akt activator, SC79. Collectively, our results demonstrated that glabridin suppressed proliferation and induced apoptosis in PC cells via regulating ROS‐mediated PI3K/Akt pathway. These findings suggested that glabridin might hold a promising prospective as a therapeutic agent against PC.