PAI-1/PIAS3/Stat3/miR-34a forms a positive feedback loop to promote EMT-mediated metastasis through Stat3 signaling in Non-small cell lung cancer.

AIM: This study intented to clarify the intracellular effect of PAI-1 on Non-small cell lung cancer (NSCLC) metastasis and the precise mechanism involved. METHODS: The metastatic properties of NSCLC cells were determined by transwell assays and wound-healing assay in vitro. The mRNA and protein expressions of genes were analyzed by Real-time qPCR and western blot, respectively. Pulmonary metastasis model of NSCLC cells was established to evaluate the pro-metastasis effect of PAI-1 and anti-metastatic effect of miR-34a in vivo. The gene targets of miR-34a were confirmed by luciferase reporter assays. Chromatin immunoprecipitation assay was employed to detect the transcriptional regulation of miR-34a. Co-immunoprecipitation assay was performed to observe the interaction of proteins. RESULTS: PAI-1, which was elevated in NSCLC patients with recurrence and metastasis, augmented NSCLC metastasis and was negatively related to the prognosis of NSCLC. miR-34a, which was decreased in NSCLC patients with metastasis, attenuated NSCLC metastasis and was positively correlated with the prognosis of NSCLC. Moreover, PAI-1 was identified as the target gene of miR-34a and activated the Stat3 signaling pathway to promote epithelial-mesenchymal transition (EMT) in NSCLC cells. PAI-1 interacted with PIAS3 to regulate Stat3-dependent gene expression and miR-34a was transcriptionally suppressed by Stat3 to form a positive regulatory loop through Stat3 signaling. CONCLUSION: Our findings suggest that PAI-1 and miR-34a, which can be clinically utilized as biomarkers for the clinical prognosis or diagnosis of NSCLC, are potential targets for the treatment of NSCLC.

[Effects of reduced glutathione on plasma level of cytokines and pulmonary ultrastructure in rats with sepsis].

OBJECTIVE: To investigate the protection mechanism of reduced glutathione (GSH) in acute lung injury in rats with sepsis. METHODS: Sepsis in Sprague-Dawley (SD) rats were reproduced by cecal ligation and puncture (CLP). They were randomly divided into four groups, sham-operated group, model group, GSH treatment group and levofloxacin (LEV) treatment group. Heart blood of 7 rats in all groups was collected at 3, 6, 12, 24 hours after operation. The plasma levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were measured. The lung ultrastructure changes were observed with electron microscope at 24 hours in all groups. RESULTS: Compared with the sham-operated group, the plasma level of TNF-alpha increased more obviously at 6 hours of the model group [(227+/-28) microg/L vs. (132+/-9) microg/L, P<0.01]. Compared with the model group, the plasma level of TNF-alpha in the GSH treatment group decreased obviously [(144+/-28) microg/L], and it was obviously lower than that of LEV treatment group [(214+/-48) microg/L , both P<0.01] . No obvious difference of plasma level of TNF-alpha was found at 3, 12, 24 hours among all the groups. Compared with the sham-operated group, the plasma level of IL-6 of the model group raised obviously at 3 hours [(267.65+/-72.87) microg/L vs. (135.43+/-40.08) microg/L, P<0.01]. In the GSH treatment group, the plasma level of IL-6 [(191.97+/-62.98) microg/L] was lower than that of the model group and the LEV treatment group [(268.75+/-74.67) microg/L, both P<0.05]. The plasma level of IL-6 was not obviously different among all groups at 6, 12, 24 hours. In the model group, the injury of pulmonary ultrastructure was obvious, especially in the mitochondria of the pulmonary cells. In the GSH treatment group, the change in ultrastructure of the lung was slight. CONCLUSION: TNF-alpha and IL-6 play significant role in the development of pulmonary ultrastructure injury in acute lung injury of septic rats. Treatment with GSH was effective in preventing such injury.