MiR-22-3p suppresses NSCLC cell migration and EMT via targeting RAC1 expression.

Previous studies have demonstrated the tumor-suppressive function of microRNA-22-3p (miR-22-3p) in several cancers, whereas the significance of miR-22-3p in non-small cell lung cancer (NSCLC) remains unclear. In this study, we explored the biological function and molecular mechanism of miR-22-3p in NSCLC cells. First, we assessed the expression of miR-22-3p in NSCLC tissues and cells based on RT-qPCR and TCGA database. Compared with normal lung tissues and cells, miR-22-3p expression was dramatically decreased in lung cancer tissues and cells. miR-22-3p expression was also correlated with lymph node metastasis and tumor size, but not TNM stages. We further explored the in vitro function of miR-22-3p on the migration and epithelial-mesenchymal transition (EMT) of NSCLC cells. The results showed that overexpression of miR-22-3p suppressed the migration and EMT of NSCLC cells, whereas silencing miR-22-3p showed the opposite effect. Luciferase assay demonstrated that RAS-related C3 botulinum toxin substrate 1 (RAC1) was the target gene for miR-22-3p. Mechanistically, we demonstrated that miR-22-3p suppressed the cell migration and EMT via downregulation of RAC1 because the inhibitory effect of miR-22-3p on cell migration and EMT of NSCLC cells was reversed by RAC1 overexpression. Based on these novel data, the miR-22-3p/RAC1 axis may be an alternative target in the therapeutic intervention of NSCLC.

Regulation of CD18 stability by SIGIRR-modulated ubiquitination: new insights into the relationship between innate immune response and acute lung injury.

Inappropriate accumulation of alveolar macrophages (AMs) and subsequent excessive production of immune responses play critical roles in the pathogenesis of acute lung injury (ALI), but the core negative regulators governing innate signalling in AMs are ill defined. We have previously shown that single immunoglobin IL-1 receptor-related protein (SIGIRR), a negative regulator of IL-1 receptor and Toll-like receptor signalling, inhibits lipopolysaccharide (LPS)-induced inflammatory responses in AMs. To address the biological relevance of SIGIRR in vivo, we generated a murine ALI model via intratracheal instillation of LPS. Intriguingly, SIGIRR expression was observed to be decreased in resident and recruited macrophages during ALI. This decrease was associated with parallel induction in CD18 protein levels in LPS-challenged lung tissues. Through intranasal injection of SIGIRR lentiviral particles studies, we showed that the overexpression of SIGIRR attenuated recruitment of macrophages and neutrophils, decreased production of inflammatory cytokines and ameliorated pathological changes in lungs. Whilst exploring the basis for this phenotype, SIGIRR was found to be coexpressed with CD18 in AMs, and SIGIRR potentiated the instability of CD18 protein via enhancement of its ubiquitination and proteasome degradation. Conversely, by using CD18-/- mice, we further observed that CD18 deletion completely abolished the therapeutic effects of overexpression of SIGIRR on LPS-induced ALI. Mover, overexpression of CD18 in AMs promoted adhesion to ECM components, enhanced TLR4-mediated inflammasome activation and thereby potentiated IL-1ß production. These data collectively identify SIGIRR/CD18 as a key negative regulatory circuit maintaining innate immune homeostasis in AMs along the pathogenesis of ALI.

Negative Effects of SIGIRR on TRAF6 Ubiquitination in Acute Lung Injury In Vitro.

In this study, the effects of single immunoglobin IL-1 receptor-related protein (SIGIRR) on tumor necrosis factor- (TNF-) receptor-associated factor 6 (TRAF6) ubiquitination in acute lung injury (ALI) were evaluated in both alveolar epithelial cells and alveolar macrophage cells in vitro. Our results found that SIGIRR negatively regulated TRAF6 ubiquitination and such SIGIRR inhibition could enhance the TRAF6 expression in both alveolar epithelial cells (AECs) and alveolar macrophage cells (AMCs). SIGIRR knockdown may increase NF-κB activity via TRAF6 regulation by the classical but not the nonclassical NF-κB signaling pathway. Such modulation between TRAF6 and SIGIRR could affect cytokine secretion and exacerbate the immune response; the IL-8, NFKB1, and NFKBIA mRNA levels were reduced after SIGIRR overexpression. The current study reveals the molecular mechanisms of the negative regulatory roles of SIGIRR on the innate immune response related to the LPS/TLR-4 signaling pathway and provides evidence for strategies to clinically treat inflammatory diseases.

miR-24-3p/KLF8 Signaling Axis Contributes to LUAD Metastasis by Regulating EMT.

Reprogramming of the tumor immune microenvironment is a salient feature during metastasis in LUAD. miR-24-3p and KLF8, which are key regulators of the tumor immune microenvironment, had been proved to show metastasis-promoting property in LUAD. However, whether miR-24-3p could regulate LUAD metastasis by targeting KLF8 remains unclear. This study explored the functions and mechanisms of miR-24-3p/KLF8 signaling in advanced LUAD. The expression level of miR-24-3p and KLF8 were tested in LUAD patients, and the corelation of miR-24-3p and KLF8 was evaluated. The interaction of miR-24-3p and KLF8 was demonstrated by luciferase reporter activity assay, in vitro migration and invasion studies, and in vivo metastatic studies. miR-24-3p level was downregulated in LUAD and negatively associated with KLF8 mRNA expression. miR-24-3p controls LUAD metastasis by directly targeting KLF8 and inducing Snail and E-cadherin expressions. Targeting the miR-24-3p/KLF8/EMT axis might be of great therapeutic value to advanced LUAD patients.

Long noncoding RNA STXBP5-AS1 inhibits cell proliferation, migration, and invasion via preventing the PI3K/AKT against STXBP5 expression in non-small-cell lung carcinoma.

Long noncoding RNAs participate in carcinogenesis and tumor progression in non-small-cell lung carcinoma (NSCLC), but the mechanisms underlying NSCLC tumorigenesis remain to be fully elucidated. Here, we reported the functional role and potential mechanism of long noncoding RNA syntaxin-binding protein 5-antisense RNA 1 (STXBP5-AS1) in NSCLC. First, our data revealed that the expression levels of STXBP5-AS1 in 31 NSCLC tissues were lower than in adjacent tissues using quantitative polymerase chain reaction (qPCR) and its expression was significantly associated with tumor metastasis of NSCLC patients. Moreover, CCK-8, scratch wound healing and transwell assay suggested that upregulation of STXBP5-AS1 repressed the proliferation, migration, and invasion in A549, NCI-H292, and NCI-H460 cells. To explore the potential mechanism of STXBP5-AS1 in NSCLC, we first investigated the relationship among STXBP5-AS1, STXBP5, and AKT1 in A549 cells. Results indicated that STXBP5-AS1 was negatively related with STXBP5 and AKT1 at messenger RNA expression level using qPCR. In addition, we observed that STXBP5-AS1 had reverse effects on the protein levels of STXBP5 and phosphorylated AKT1 (p-AKT1) in A549 cells via Western blot assay, despite no significant effects on AKT1. Subsequently, LY294002, as the phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) pathway inhibitor, was used to further confirm the regulatory mechanism of STXBP5-AS1, which showed that knockdown of STXBP5-AS1 could rescue the expression of STXBP5 and p-AKT1 protein expression levels in A549 cells. Taken together, our results suggested that STXBP5-AS1, as a tumor suppressor, inhibits cell proliferation, migration, and invasion by preventing the PI3K/AKT against STXBP5 expression in NSCLC.

SIK1-LNC represses the proliferative, migrative, and invasive abilities of lung cancer cells.

BACKGROUND: Discussions regarding the correlations between long non-coding RNAs (lncRNAs) and cancers have dominated research in recent years. SIK1-LNC, a type of lncRNA and adjacent to salt-inducible kinases 1 (SIK1), has been found aberrantly expressed in lung cancer. However, its functional role in lung cancer remains largely unknown. PURPOSE: In this study, we aimed to explore the association between SIK1-LNC expression and SIK1 in lung cancer cells and further identify the impact of SIK1-LNC on the proliferation, migration invasion of lung cancer cells. PATIENTS AND METHODS: Of the 30 patients with non-small-cell lung carcinoma from Zhongnan Hospital of Wuhan University, RT-qPCR was performed to detect SIK1 and SIK1-LNC expressions in patients' samples. Overexpression and knockdown experiments were conducted to analyze the SIK1 and SIK1-LNC expressions in lung cancer cell lines. CCK-8, Brdu, scratch wound-healing, and Transwell assays were respectively employed to evaluate the proliferative, migrative, and invasive abilities of lung cancer cells. RESULTS: Both SIK1-LNC and SIK1 expression levels were evidently downregulated in 30 lung cancer tissues. SIK1-LNC expression was bound up with clinicopathologic features, including lymph node metastasis and distant metastasis. SIK1 expression showed a positive tendency with SIK1-LNC expression in lung cancer cells. SIK1-LNC exerted a significant repression on cell proliferatiive, miogrative and invasive abilities of lung cancer cells. CONCLUSION: Our findings suggested that SIK1-LNC may act as a novel biomarker and therapeutic target for lung cancer.

lincROR influences the stemness and crizotinib resistance in EML-ALK+ non-small-cell lung cancer cells.

INTRODUCTION: Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) is identified as an important pathogenic factor in patients with non-small-cell lung cancer (NSCLC) and could induce a stem-like phenotype in NSCLC cells. Crizotinib is commonly used for EML4-ALK+ NSCLC treatment, but its acquired resistance results in tumor recurrence. Long intergenic noncoding RNA, regulator of reprogramming (lincROR) is related to the acquisition and maintenance of self-renewal and stemness features of cancer stem cells. It has been documented that lincROR is implicated in chemoresistance. However, the correlations of lincROR and EML4-ALK in stem cell-like properties and of lincROR and crizotinib resistance in NSCLC cells are yet to be elucidated. PATIENTS AND METHODS: In the present study, we investigated the expression profile of lincROR in EML-ALK NSCLC tissues, and the potential role of lincROR in prognosis was then analyzed. Subsequently, its association with stem cell-like properties of EML-ALK+ NSCLC cells was determined. Furthermore, the correlation of lincROR with crizotinib and the effects of lincROR and crizotinib on cell viability of EML4-ALK+ NSCLC cells were all explored. RESULTS: The results showed that lincROR expression was upregulated in EML4-ALK+ NSCLC tissues relative to EML4-ALK- NSCLC tissues. Low-expressed lincROR was related to a favorable prognosis of patients with EML-ALK NSCLC. lincROR overexpression could enhance the stemness features of EML-ALK+ NSCLC cells which were repressed by ALK knockdown. CONCLUSION: We found that lincROR expression was significantly inhibited because of the increased concentration of crizotinib in EML4-ALK+ NSCLC cells. Furthermore, lincROR overexpression increased cell viability of EML4-ALK+ NSCLC cells, which was impaired by crizotinib. Conjointly, these results suggested the important role of lincROR in EML-ALK+ NSCLC. lincROR may serve as a potential therapeutic target to overcome chemotherapy resistance in EML-ALK+ NSCLC.

Melittin Constrains the Expression of Identified Key Genes Associated with Bladder Cancer.

This work is aimed at investigating the effect of melittin on identified key genes in bladder cancer (BC) and further providing a theoretical basis for BC treatment. GSE35014 downloaded from the Gene Expression Omnibus (GEO) database was used to screen differentially expressed genes (DEGs) in BC cells and control. Results showed that a total of 389 upregulated and 169 downregulated genes were identified. Subsequently, GO analysis, KEGG pathway enrichment analysis, and PPI network analysis were employed to disclose the crucial genes and signaling pathways involved in BC. Fifteen module-related DEGs and their associated signaling pathways were obtained according to the PPI network and modular analyses. Based on the analysis of articles retrieved in the PubMed database, we found that melittin could induce apoptosis and constrain the progression of tumor cells as a result of regulating critical cancer-related signaling pathways, such as PI3K-Akt and TNF signaling pathways. Furthermore, PI3K-Akt and TNF signaling pathways were also found to be associated with module-related DEGs according to biological analyses. At last, qRT-PCR analysis demonstrated that melittin could constrain the expression of module-related DEGs (LPAR1, COL5A1, COL6A2, CXCL1, CXCL2, and CXCL3) associated with PI3K-Akt and TNF signaling pathways in BC cells. Functional assays revealed that melittin could constrain the proliferative and migrated abilities of BC cells. Conjointly, these findings provide a theoretical basis for these six genes as drug-sensitive markers of melittin in BC treatment.

miR-24-3p/FGFR3 Signaling as a Novel Axis Is Involved in Epithelial-Mesenchymal Transition and Regulates Lung Adenocarcinoma Progression.

Our previous studies showed that Fibroblast growth factor receptor 3 (FGFR3) contributed to cell growth in lung cancer. However, the correlation between FGFR3 and tumor progression, coupled with the underlying mechanisms, are not fully understood. The clinical significance of FGFR3 was determined in two cohorts of clinical samples (n = 22, n = 78). A panel of biochemical assays and functional experiments was utilized to elucidate the underlying mechanisms and effects of FGFR3 and miR-24-3p on lung adenocarcinoma progression. Upregulated FGFR3 expression indicated an adverse prognosis for lung adenocarcinoma individuals and promoted metastatic potential of lung adenocarcinoma cells. Owing to the direct regulation towards FGFR3, miR-24-3p could interfere with the potential of proliferation, migration, and invasion in lung adenocarcinoma, following variations of EMT-related protein expression. As a significant marker of EMT, E-cadherin was negatively correlated with FGFR3, of which ectopic overexpression could neutralize the antitumour effects of miR-24-3p and reverse its regulatory effects on EMT markers. Taken together, these findings define a novel insight into the miR-24-3p/FGFR3 signaling axis in regulating lung adenocarcinoma progression and suggest that targeting the miR-24-3p/FGFR3 axis could be an effective and efficient way to prevent tumor progression.

The methylation induced by protein arginine methyltransferase 5 promotes tumorigenesis and progression of lung cancer.

Arginine methylation as a common pattern of post-translational modification is involved in many cellular biological processes. Protein arginine methyltransferase 5 (PRMT5) is a primary enzyme in charge of symmetric dimethylation (me2s) of arginine residues. Increasing literatures lead to the belief that PRMT5, as a potential oncogene, plays crucial roles in the tumorigenesis and progression of cancers. First of all, PRMT5 is overexpressed in several cancer cells, with various sub-cellular localization in different type of cells and different phases. Besides, PRMT5 participates in controlling cellular proliferation, differentiation, invasion, migration as well apoptosis through histone and other protein methylation. Moreover, PRMT5 is essential for growth and metastasis of lung cancer cells, and its overexpression indicates a poor clinical outcome of lung cancer. Therefore, in this review, we reviewed the substantial new literatures on PRMT5 and its functions, in order to highlight the significance of understanding this essential enzyme in lung cancer tumorigenesis and progression.

Low Molecular Weight Heparin Nebulization Attenuates Acute Lung Injury.

BACKGROUND: As acute lung injury (ALI) caused high mortality rate, it is important to explore the protection and treatment of ALI. The aim of the current study is to evaluate the effect of low molecular weight heparin (LMWH) nebulization on attenuating acute lung injury and the associated mechanism. METHODS: The arterial blood gas, total protein content in bronchoalveolar lavage fluid, lung wet/dry weight ratio, malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, and Akt phosphorylation were evaluated after the ALI rabbits were treated with or without LMWH nebulization. RESULTS: PaO2 was increased and lung wet/dry weight ratio as well as total protein content in BALF was decreased after LMWH nebulization. After the application of LMWH nebulization therapy, the SOD and GSH-Px activity was rebounded and the increase of MDA content was significantly inhibited. The Akt protein phosphorylation level was decreased after LMWH nebulization therapy. CONCLUSIONS: LMWH nebulization treatment can relieve the traumatic ALI in rabbits and inhibit oxidative stress possibly by suppressing the Akt phosphorylation.

Attenuation of deregulated miR-369-3p expression sensitizes non-small cell lung cancer cells to cisplatin via modulation of the nucleotide sugar transporter SLC35F5.

Deregulation of the microRNAs (miRNAs), a cluster of important posttranscriptional regulators, has been frequently associated with lung cancer (LCa). However, the emerging mechanism for how miRNAs is linked causally in the development of LCa chemoresistance is poorly understood. Herein, we established for the time the up-regulation of miR-369-3p in cisplatin (DDP)-resistant nonsmall cell lung cancer (NSCLC) tissues and cells. Its deregulation was found to be correlated to the magnitude of malignancy in well-characterized LCa cells. Functionally, inhibition of miR-369-3p sensitized LCa cells to DDP and suppressed the invasive capability in the presence of DDP treatment, whereas miR-369-3p overexpression promoted DDP resistance and thereby enhanced LCa cells invasiveness. Mechanistically, bioinformatics coupled with luciferase and gain-of-function, loss-of-function assays revealed that miR-369-3p may regulate DDP chemoresistance by directly targeting the 3' untranslated region (UTR) of human solute carrier 35F5 (SLC35F5), as application of miR-369-3p inhibitors or reintroduction of epigenetically silenced SLC35F5 both individually sensitized LCa cells to DDP, but combined treatment with miR-369-3p inhibitors and SLC35F5 overexpression failed to sensitized LCa cells further to DDP-elicited cell death. Our results provide evidence that the oncomiR effect of miR-369-3p may be mediated through disrupting the nucleotide sugar transportation and that SLC35F5 is a key effector of this chemoresistance-promoting activity.

Pulmonary resident neutrophils regulate the production of GM-CSF and alveolar macrophages.

Alveolar macrophages exist in the lung airspaces, and their differentiation and function are considerably regulated by the microenvironment. In this study, we examine the important role of resident neutrophil/IL-23/granulocyte/macrophage colony-stimulating factor (GM-CSF) axis in the development and preferential phenotype of alveolar macrophages under physiological conditions. Using CD18-deficient (CD18(-/-) ) mice, we show a correlation between increased granulopoiesis and enhanced alveolar macrophage development in an IL-23- and GM-CSF-dependent manner. The apoptotic neutrophils could inhibit the secretion of IL-23 from alveolar macrophages, which is important for the production of GM-CSF, and depletion of neutrophils disrupted the regulation of IL-23 and GM-CSF. This study reveals a mechanism for the regulation of the local alveolar macrophage population and function by neutrophil apoptosis in the circulatory system.

The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis.

Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli-germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli-germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation.

α-Linolenic acid intake attenuates myocardial ischemia/reperfusion injury through anti-inflammatory and anti-oxidative stress effects in diabetic but not normal rats.

BACKGROUND AND AIMS: Patients with diabetes show enhanced susceptibility to myocardial ischemia/reperfusion (MI/R) injury. Epidemiological studies indicated that consumption of α-linolenic acid (ALA) significantly reduces the risk of cardiac events in post-acute myocardial infarction patients. The present study attempted to investigate the effects of ALA intake on MI/R injury in normal and diabetic rats and its mechanisms. METHODS: The high-fat diet-fed streptozotocin (HFD-STZ) rat model was developed. Age-matched normal and HFD-STZ rats were randomly assigned to receive normal diet or ALA (oral gavage, 500 µg/kg per day). After 4 weeks of feeding, animals were subjected to 30 min of myocardial ischemia and 4 or 6 h of reperfusion. RESULTS: Compared with the normal control, HFD-STZ rats showed more severe myocardial functional impairment and injury. Although ALA intake for 4 weeks did not change myocardial function and injury in normal rats, it significantly improved the instantaneous first derivation of left ventricle pressure, reduced infarct size, plasma creatine kinase and lactate dehydrogenase activities, and apotosis at the end of reperfusion in HFD-STZ diabetic rats. Moreover, ALA intake not only significantly reduced tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) concentrations but reduced the increase in superoxide production and malonaldialdehyde formation and simultaneously enhanced the antioxidant capacity in the diabetic hearts. Myocardial PI3K expression and Akt phosphorylation were increased by ALA intake in diabetic but not normal rats. CONCLUSIONS: Chronic ALA intake confers cardioprotection in MI/R by exerting anti-inflammatory and anti-oxidative stress effects in diabetic but not normal rats, which is possibly through PI3K-Akt-dependent mechanism.