TY - JOUR T1 - Tetrandrine Enhances H<sub>2</sub>O<sub>2</sub>-Induced Apoptotic Cell Death Through Caspase-dependent Pathway in Human Keratinocytes JF - In Vivo JO - In Vivo SP - 2047 LP - 2057 DO - 10.21873/invivo.12474 VL - 35 IS - 4 AU - YI-CHING CHENG AU - CHAO-LIN KUO AU - SHENG-YAO HSU AU - TZONG-DER WAY AU - CHING-LING CHENG AU - JAW-CHYUN CHEN AU - KUO-CHING LIU AU - SHU-FEN PENG AU - WAI-JANE HO AU - FU-SHIN CHUEH AU - WEN-WEN HUANG Y1 - 2021/07/01 UR - http://iv.iiarjournals.org/content/35/4/2047.abstract N2 - Background: Tetrandrine, a bis-benzylisoquinoline alkaloid, induces apoptosis of many types of human cancer cell. Hydrogen peroxide (H2O2) is a reactive oxygen species inducer; however, there are no reports to show whether pre-treatment of tetrandrine with H2O2 induces more cell apoptosis than H2O2 alone. Thus, the present study investigated the effects of tetrandrine on H2O2-induced cell apoptosis of human keratinocytes, HaCaT, in vitro. Materials and Methods: HaCaT cells were pre-treated with and without tetrandrine for 1 h, and then treated with H2O2 for examining cell morphological changes and cell viability using contrast-phase microscopy and propidium iodide (PI) exclusion assay, respectively. Cells were measured apoptotic cell death by using annexin V/PI double staining and further analyzed by flow cytometer. Cells were further assessed for DNA condensation using 2-(4-amidinophenyl)-6-indolecarbamidine staining. Western blotting was used to measure expression of apoptosis-associated proteins and confocal laser microscopy was used to measure the protein expression and nuclear translocation from the cytoplasm to nuclei. Results: Pre-treatment of tetrandrine for 1 h and treatment with H2O2 enhanced H2O2-induced cell morphological changes and reduced cell viability, whilst increasing apoptotic cell death and DNA condensation. Furthermore, tetrandrine significantly increased expression of reactive oxygen species-associated proteins such as superoxide dismutase (Cu/Zn) and superoxide dismutase (Mn) but significantly reduced the level of catalase, which was also confirmed by confocal laser microscopy. It also increased expression of DNA repair-associated proteins ataxia telangiectasia mutated, ataxia-telangectasia and Rad3-related, phospho-P53, P53 and phosphorylated histone H2AX, and of pro-apoptotic proteins BCL2 apoptosis regulator-associated X-protein, caspase-3, caspase-8, caspase-9 and poly ADP ribose polymerase in HaCaT cells. Conclusion: These are the first and novel findings showing tetrandrine enhances H2O2-induced apoptotic cell death of HaCaT cells and may provide a potent approach for the treatment of proliferated malignant keratinocytes. ER -