AIM OF THE STUDY: The purpose of this study was to determine the in situ cytotoxicity effect P. macrocarpa fruit ethyl acetate fraction (PMEAF) and the underlying molecular mechanism of cell death.
MATERIALS AND METHODS: MDA-MB-231 cells were incubated with PMEAF for 24h. Cell cycle and viability were examined using flow cytometry analysis. Apoptosis was determined using the Annexin V assay and also by fluorescence microscopy. Apoptosis protein profiling was detected by RayBio® Human Apoptosis Array.
RESULTS: The AO/PI staining and flow cytometric analysis of MDA-MB-231 cells treated with PMEAF were showed apoptotic cell death. The cell cycle analysis by flow cytometry analysis revealed that the accumulation of PMEAF treated MDA-MB-231 cells in G0/G1 and G2/M-phase of the cell cycle. Moreover, the PMEAF exert cytotoxicity by increased the ROS production in MDA-MB-231 cells consistently stimulated the loss of mitochondrial membrane potential (∆Ψm) and induced apoptosis cell death by activation of numerous signalling proteins. The results from apoptosis protein profiling array evidenced that PMEAF stimulated the expression of 9 pro-apoptotic proteins (Bax, Bid, caspase 3, caspase 8, cytochrome c, p21, p27, p53 and SMAC) and suppressed the 4 anti-apoptotic proteins (Bcl-2, Bcl-w, XIAP and survivin) in MDA-MB-231 cells.
CONCLUSION: The results indicated that PMEAF treatment induced apoptosis in MDA-MB-231 cells through intrinsic mitochondrial related pathway with the participation of pro and anti-apoptotic proteins, caspases, G0/G1 and G2/M-phases cell cycle arrest by p53-mediated mechanism.
METHODS: A sample of 837 Chinese students in elementary and middle school was collected for this study. The Perceived Stress Scale, the Social Support Scale, the Emotional Intelligence Scale, and the Post-Stress Growth Scale were employed to examine them. The data were analyzed using SPSS 25.0 software.
RESULTS: The results indicate a significant negative association between perceived stress and post-stress growth. Among perceived stress and social support, the former acted as a mediator, while the latter as a moderator. This study sheds light on the post-stress growth of Chinese left-behind children. The findings validated a model of moderated mediation that shows the relationship between perceived stress, emotional intelligence, social support, and post-stress growth.
CONCLUSION: This study confirmed that social support is one of the most important factors among left-behind children, from perceived stress to post-stress growth. Furthermore, the study reveals that emotional intelligence can adjust the relationship between perceived stress and social support to post-stress growth. Therefore, for both family education and school education, the result provides a new direction.