Protein from Hylocereus polyrhizus protects MRC-5 cells against hydrogen peroxide (H2O2)-induced damage

The cytoprotective and potential molecular mechanisms of Hylocereus polyrhizus protein (RFPP) were investigated on the hydrogen peroxide (H 2 O 2 )-triggered damage in normal human embryonic lung (MRC-5) cells. An MTT assay was conducted to assess the MRC-5 cell viability after exposure to H 2 O 2 or RFPP. Cell cycle distribution and apoptosis were explored via flow cytometry. The contents of related proteins were assessed via western blot. MRC-5 cells exhibited markedly decreased cellular viability after treatment with H 2 O 2 ; however, treatment with RFPP suppressed this decrease. Additionally, RFPP interference dampened H 2 O 2 -triggered intracellular apoptosis levels and increased H 2 O 2 -triggered intracellular S phase. In these processes, the contents of phosphorylated ( p )-AKT along with p -mTOR proteins were downregulated in 120 µM H 2 O 2 -treated cells compared with vehicle-treated cells. Nevertheless, in MRC-5 cells inoculated with RFPP, the levels expression of these proteins were reversed. To conclude, RFPP protected MRC-5 cells from H 2 O 2 -triggered damage via activation of the PI3K/AKT/mTOR cascade.