Plasminogen Activator Inhibitor 1 Promotes Immunosuppression in Human Non-Small Cell Lung Cancers by Enhancing TGF-Β1 Expression in Macrophage

Abstract

Background: Plasminogen activator inhibitor-1 (PAI-1) has been regarded as a risk factor for thrombosis and atherosclerosis. Since it has been shown that PAI-1 can activate macrophages through Toll-like receptor-4, we sought to investigate the role of PAI-1 in the tumor microenvironment. Methods: The expression and distribution patterns of PAI-1 and transforming growth factor beta (TGF-β) were measured in 60 non-small cell lung cancer (NSCLC) tumors. A statistical correlation analysis was performed between PAI-1 and TGF-β expression and distribution in each tumor. The distribution of tumor-associated macrophages (TAMs) was also measured and its correlation to PAI-1 levels was analyzed. Levels of secreted CCL-17, CCL-22, IL-6 and TGF-β were measured in cell cultures of human macrophage cell lines THP-1 and U937 treated with PAI-1. Levels of secreted PAI-1 were monitored in cell cultures of human NSCLCs cell lines 95D and A549 treated with TGF-β. Secreted proteins were measured in cell culture supernatants using ELISA. Changes in downstream signaling pathways were investigated using western blot. Results: PAI-1 and TGF-β were found to be overexpressed in human NSCLCs. PAI-1 expression was tightly correlated to TGF-β expression as well as the percentage of TAMs. PAI-1 treatment increased the expression of TAM-associated cytokines and chemokines, including CCL-17, CCL-22, and IL-6. PAI-1 treatment was also observed to enhance TGF-β expression in macrophage cell lines through an IL-6 autocrine/paracrine manner. The effects on TGF-β expression were blocked by NF-κB and STAT3 inhibition. Interestingly, TGF-β also increased levels of secreted PAI-1 in NSCLC cells through SMAD3-dependent signaling, therefore resulting in a feed-forward loop. However, this loop could be blocked by NF-κB, STAT3 and SMAD3 signaling inhibition, as well as treatment with a high concentration of TGF-β. Conclusion: PAI-1 and TGF-β promote NSCLC tumor cells and TAMs and might be valuable targets for cancer immunosuppression.

NR4A1 Promotes Diabetic Nephropathy by Activating Mff-Mediated Mitochondrial Fission and Suppressing Parkin-Mediated Mitophagy

“…Consistently with our findings, previous studies have reported that NR4A1 activation was noted in fatty liver disease and atherosclerosis [24,25] and that the genetic deletion of NR4A1 or pharmacological inhibition of NR4A1 retards or prevents the progression of nonalcoholic fatty liver and atherosclerosis [66,67]. Collectively, these observations have demonstrated the sufficiency of NR4A1 to exacerbate chronic metabolic diseases, which may highlight a new method for treating chronic metabolic disorders by targeting NR4A1.…”

“…The NR4A1 activation induced by a high-fat diet promotes Drp1 phosphorylation and Bnip3 transcriptional arrest, selectively stimulating Drp1-mediated mitochondrial fission and inhibiting Bnip3-related mitophagy [24]. In addition, upregulated NR4A1 also induces high-fat associated endothelial dysfunction and atherosclerosis formation by regulating Parkin-mediated mitophagy activity [25]. On this basis, we aimed to investigate whether NR4A1 is upregulated by hyperglycemia and activates Mff-required mitochondrial fission and represses Parkin-related mitophagy, finally leading to mitochondrial dysfunction, glomerular mitochondrial apoptosis, and the development of DN.…”

Heterogeneity and targeted therapy-induced adaptations in lung cancer revealed by longitudinal single-cell RNA sequencing

“…Plasminogen is then degraded to plasmin through the activity of PLAT and/or PLAU leading to activation of metalloproteinases and degradation of fibrin. SERPINE1 shows increased expression in a number of cancer subtypes and plays important roles in cell adhesion, invasion, tumor vascularization, radio-resistance, and immunosuppression (Kubala et al, 2018;Zhu et al, 2017). High expression of the plasminogen activation signature correlated with worse OS (p=0.0029) within the TCGA lung adenocarcinoma RNAseq dataset ( Figure 3J).…”

“…Several genes in the plasminogen activation pathway were significantly overexpressed (ANXA2, PLAT, PLAUR, PLAU) ( Figure 3H) along with the plasminogen inhibitor SERPINE1 (PAI1) (p<0.0001, Figure 3I, Supplemental Figure 3G). ANXA2 and PLAUR are the receptor proteins in the plasminogen activation cascade and involved in inflammation, angiogenesis, invasion and metastasis, via degradation of the extracellular matrix (Kubala et al, 2018;Zhu et al, 2017). Signaling is initiated when ANXA2 or PLAU binds to PLAT (uTa) or PLAU (uPa), respectively.…”

Enterovirus A71 capsid protein VP1 increases blood–brain barrier permeability and virus receptor vimentin on the brain endothelial cells

“…EV-A71 VP1 neutralizing antibody (Cat.No.40013-H136) was purchased from Sino Biological (Beijing, China). The NF-κB inhibitor (BAY 11-7082, S2913) (Mosteiro et al 2016) and Smad3 inhibitor (SIS3 HCl, S7959) (Zhu et al 2017) were purchased f r o m S e l l e c k ( S h a n g h a i , C h i n a ) . F l u o r e s c e i n isothiocyanate-dextran (FD4) and dimethyl sulfoxide (DMSO) (V900090) were purchased from Sigma-Aldrich (MO, USA).…”