MiR-199a-5p–HIF-1α-STAT3 Positive Feedback Loop Contributes to the Progression of Non-Small Cell Lung Cancer

Abstract

Background: Non-small cell lung cancer (NSCLC) is the most common malignancy worldwide. MiR-199a-5p has been reported to play important roles in multiple tumors, inclusive of NSCLC. However, little is definitively known pertaining to its explicit mechanism of action in NSCLC.Methods: The expressions of miR-199a-5p and hypoxia-inducible factor-1α (HIF-1α) mRNA were quantified employing qRT-PCR. H1299 and A549 cells were transiently transfected with miR-199a-5p mimics or inhibitors. Then, CCK-8 assays, flow cytometry analysis, and Transwell assay were performed for detecting cell proliferation, cell cycle, apoptosis, migration, and invasion of NSCLC cells, respectively. HIF-1α, signal transducer and activator of transcription 3 (STAT3), and p-STAT3 expressions were detected via Western blotting. Bioinformatic analysis and dual-luciferase assay were performed to investigate the interactions among miR-199a-5p, HIF-1α, and STAT3. Xenograft models were established with nude mice for further analyzing the bevacizumab resistance of NSCLC cells.Results: MiR-199a-5p expression was markedly attenuated in NSCLC tissues and cell lines. Overexpression of miR-199a-5p repressed the proliferation, migration, and invasion but induced the apoptosis of NSCLC cells. HIF-1α was identified as a direct target of miR-199a-5p. There was a positive feedback loop among miR-199a-5p, HIF-1α, and STAT3. Co-transfection of HIF-1α or STAT3 overexpression plasmids counteracted the effects of miR-199a-5p. In vivo experiments indicated that the feedback loop was in association with the bevacizumab resistance of NSCLC cells.Conclusion: MiR-199a-5p blocked the progression of NSCLC and sensitized NSCLC cells to bevacizumab by suppressing HIF-1α and STAT3, while the HIF-1α/STAT3 axis suppressed the expression of miR-199a-5p, which forms a positive feedback loop to promote the sustaining progression of NSCLC.

miR-199a Downregulation as a Driver of the NOX4/HIF-1α/VEGF-A Pathway in Thyroid and Orbital Adipose Tissues from Graves′ Patients

“…The second counterargument arises from the upregulation of transcription factor STAT3 signaling, which was observed in the thyroid, as well as in orbital adipose tissue. Alteration in the phosphorylation status of STAT3 on its activation site (Tyr 705) correlates in these tissues with miR-199a repression, in line with the ability of STAT3 to negatively regulate miR-199a previously described in cardiomyocytes under hypoxic conditions [ 35 , 36 , 37 , 54 ]. This observation is particularly interesting in view of the recent data from Ko et al who proposed STAT3 as a potential therapeutic target in GO [ 55 ].…”

“…Our results hence suggested that miR-199a-5p directly targets NOX4, HIF-1α and VEGF-A in human thyrocytes. By regulating NOX4, HIF-1α and VEGF-A, miR-199a could thus be considered a regulator of ROS production, OS and angiogenesis, as it has been proposed in other cell types [ 31 , 33 , 34 , 35 , 36 ] ( Figure 4 B).…”

“…Their in vitro results on GO orbital fibroblasts also suggests that STAT3 participates in the control of proinflammatory cytokine production, oxidative stress responses and adipogenesis. Another interesting link, although only described in lung cancer, is the positive feedback loop composed of miR-199a-5p/HIF1-α and STAT3 [ 36 ]. Of note, a post-transcriptional regulation could co-exist.…”

Multicellular Effects of STAT3 in Non-small Cell Lung Cancer: Mechanistic Insights and Therapeutic Opportunities

“…Dysregulated activation of the STAT3/miR-135b/NFκB signaling axis also contributes to progression of NSCLC by enhancing cell migration, invasion, and angiogenesis [ 51 ]. Additionally, a miR-199a-5p/HIF1α/STAT3 positive feedback loop promotes resistance of NSCLC cells to the anti-angiogenic drug bevacizumab [ 52 ], while miR-206 decreases angiogenesis in A549 xenografts by inhibiting the STAT3/HIF1α/VEGF pathway [ 45 ]. Collectively, these findings demonstrate the pivotal role of STAT3 in regulating angiogenesis in NSCLC.…”

Regulation of Hypoxic Signaling and Oxidative Stress via the MicroRNA–SIRT2 Axis and Its Relationship with Aging-Related Diseases

“…Recently, miR-199a-5p was found to induce cytotoxicity in oxygen-glucose deprivation and reperfusion (OGD/R)-injured H9c2 cells, a model of acute myocardial infarction, via the reduced expression of HIF-1α [ 49 ]. In addition, miR-199a-5p is reported to repress the proliferation, migration, and invasion of non-small cell lung cancer by suppressing HIF-1α and signal transducer and activator of transcription 3 [ 50 ]. Overall, miR-199a-5p inhibits cancer progression and promotes cytotoxicity by OGD.…”