No abstract

Cerebral ischemia/reperfusion injury (CIRI) leads to injury in distant organs, most commonly the lungs, although limited studies have examined self‐protective mechanisms during CIRI‐induced lung injury. Here, we investigated self‐protective mechanisms that attenuate stress‐related injury and promote the angiogenetic repair of epithelial function during CIRI‐induced lung injury by measuring nuclear factor erythroid‐related factor 2 (Nrf2) and hypoxia‐inducible factor‐1α (HIF‐1α) levels. A CIRI model was established in male Sprague–Dawley rats by blocking the middle cerebral artery. Rats were divided into five subgroups based on the reperfusion time (6, 12, 24, 48, and 72 hr). Lung injury was assessed using a semiquantitative score and a thiobarbituric acid‐based method of determining malonaldehyde production. Lung tissue angiogenesis was detected by CD34 and CD31 immunolabeling. Changes in Nrf2, heme oxygenase‐1 (HO‐1), HIF‐1α, vascular‐endothelial growth factor (VEGF), phosphatidylinositol 3‐kinase (PI3K), extracellular‐regulated kinase1/2 (ERK1/2), and phospho‐ERK1/2 ( p‐ERK1/2) protein‐ and mRNA‐expression levels were measured by immunohistochemistry and reverse transcription polymerase chain reactions, respectively. Oxidative stress induced by cerebral ischemia/reperfusion (CI/R) caused lung injury. Expression of the Nrf2/HO‐1 antioxidative stress pathway in lung tissues increased following CI/R, peaking after 24 hr. PI3K, ERK, and p‐ERK1/2, which act upstream of Nrf2/HO‐1, were expressed at higher levels in the CI/R‐model group, consistent with the general trends observed for Nrf2/HO‐1. Within 72 hr post‐CI/R, HIF‐1α, and VEGF expression significantly increased versus the sham group. Thus, during CIRI‐induced lung injury, the body may upregulate antioxidative stress activities and promote angiogenesis to repair the endothelial barrier through the Nrf2/HO‐1 and HIF‐1α/VEGF signaling pathways, enabling self‐protection.

Puerarin has recently been demonstrated to play anti-cancer roles in a series of human cancers, including non-small cell lung cancer (NSCLC), possibly through regulation of cancer-related microRNAs (miRNAs). The purpose of the present study was to further investigate the detailed role and underlying mechanism of puerarin on NSCLC progression. Cell viability and apoptosis were assessed using the Cell Counting kit-8 (CCK-8) assay and flow cytometry, respectively. Transwell assays were performed to determine cell migration and invasion abilities. The qRT-PCR assay was employed to detect the expression of miR-342 and cyclin D1 (CCND1) mRNA, and CCND1 protein expression was evaluated by western blotting. The targeted interaction between miR-342 and CCND1 was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. We found that our data demonstrated that puerarin repressed cell viability, migration, invasion and cell cycle progression, and enhanced the apoptosis of NSCLC cells. miR-342 overexpression hindered the migration, invasion and cell cycle progression, and accelerated the apoptosis of NSCLC cells. miR-342 inhibited CCND1 expression by directly binding to the 3'-UTR of CCND1. Moreover, miR-342 overexpression-mediated anti-migration, anti-invasion, anti-cell cycle progression, and pro-apoptotic effects were abated by co-transfection of pcDNA-CCND1. More importantly, puerarin inhibited CCND1 expression by upregulating miR-342. Additionally, puerarinhampered NSCLC cell progression in vitro and tumor growth in vivo by upregulating miR-342. In conclusion, our study suggested that puerarin hampered NSCLC progression in vitro and in vivo at least partly through regulating miR-342/CCND1 axis, highlighting a novel mechanism of puerarin exerting anti-cancer property in NSCLC.