Corrigendum: Clinical characteristics and prognosis of patients with pulmonary mucoepidermoid carcinoma: a SEER-based analysis.

[This corrects the article DOI: 10.3389/fonc.2021.601185.].

Inhibition of OGG1 ameliorates pulmonary fibrosis via preventing M2 macrophage polarization and activating PINK1-mediated mitophagy.

BACKGROUND: 8-Oxoguanine DNA glycosylase (OGG1), a well-known DNA repair enzyme, has been demonstrated to promote lung fibrosis, while the specific regulatory mechanism of OGG1 during pulmonary fibrosis remains unclarified. METHODS: A bleomycin (BLM)-induced mouse pulmonary fibrosis model was established, and TH5487 (the small molecule OGG1 inhibitor) and Mitochondrial division inhibitor 1 (Mdivi-1) were used for administration. Histopathological injury of the lung tissues was assessed. The profibrotic factors and oxidative stress-related factors were examined using the commercial kits. Western blot was used to examine protein expression and immunofluorescence analysis was conducted to assess macrophages polarization and autophagy. The conditional medium from M2 macrophages was harvested and added to HFL-1 cells for culture to simulate the immune microenvironment around fibroblasts during pulmonary fibrosis. Subsequently, the loss- and gain-of function experiments were conducted to further confirm the molecular mechanism of OGG1/PINK1. RESULTS: In BLM-induced pulmonary fibrosis, OGG1 was upregulated while PINK1/Parkin was downregulated. Macrophages were activated and polarized to M2 phenotype. TH5487 administration effectively mitigated pulmonary fibrosis, M2 macrophage polarization, oxidative stress and mitochondrial dysfunction while promoted PINK1/Parkin-mediated mitophagy in lung tissues of BLM-induced mice, which was partly hindered by Mdivi-1. PINK1 overexpression restricted M2 macrophages-induced oxidative stress, mitochondrial dysfunction and mitophagy inactivation in lung fibroblast cells, and OGG1 knockdown could promote PINK1/Parkin expression and alleviate M2 macrophages-induced mitochondrial dysfunction in HFL-1 cells. CONCLUSION: OGG1 inhibition protects against pulmonary fibrosis, which is partly via activating PINK1/Parkin-mediated mitophagy and retarding M2 macrophage polarization, providing a therapeutic target for pulmonary fibrosis.

Quercetin influences intestinal dysbacteriosis and delays alveolar epithelial cell senescence by regulating PTEN/PI3K/AKT signaling in pulmonary fibrosis.

Pulmonary fibrosis is a chronic and progressive lung disease with high mortality. This study aims to explore the protective mechanism of quercetin against pulmonary fibrosis regarding cell senescence and gut microbiota. Rats were intratracheally injected with bleomycin (BLM) to establish a pulmonary fibrosis rat model. RLE-6TN cells were stimulated with BLM to build the model of alveolar epithelial cell senescence, and RLE-6TN-derived conditional medium (CM) was harvested to further culture fibroblasts. Histopathological changes were assessed by H&E and Masson staining. α-SMA expression was assessed by immunofluorescence assay. Senescence-associated ß-galactosidase (SA-ß-gal) staining and senescence-associated secretory phenotype (SASP) cytokine assay were conducted to assess cellular senescence. Gut microbiota was analyzed by 16S rRNA gene sequencing. The fibrosis-, senescence-, and PTEN/PI3K/AKT signaling-related proteins were examined by western blot. In BLM-induced pulmonary fibrosis rats, quercetin exerted its protective effects by reducing histological injury and collagen deposition, lessening cellular senescence, and regulating gut microbiota. In BLM-induced alveolar epithelial cell senescence, quercetin inhibited senescence, lessened SASP cytokine secretion of alveolar epithelial cells, and further ameliorated collagen deposition in fibroblasts. In addition, quercetin might exert its functional effects by regulating the PTEN/PI3K/AKT signaling pathway. Moreover, quercetin regulated intestinal dysbacteriosis in BLM-induced pulmonary fibrosis rats, especially boosting the abundance of Akkermansia. To conclude, our findings provide an in-depth understanding of the potential mechanism behind the protective role of quercetin against pulmonary fibrosis.

Contribution of Adiponectin/Carnitine Palmityl Transferase 1A-Mediated Fatty Acid Metabolism during the Development of Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that leads rapidly to death. The present study is aimed at discovering the in-depth pathogenesis of IPF, exploring the role of adiponectin/carnitine palmityl transferase 1A- (APN/CPT1A-) mediated fatty acid metabolism during the development of IPF, and excavating its potential mechanism. Here, THP-1 cells were differentiated into M0 macrophages, followed by polarization to M1 macrophages upon hypoxia. Subsequently, lung fibroblast HFL-1 cells were stimulated by M1 macrophages to simulate hypoxia-related IPF condition in vitro. It was discovered that the stimulation of M1 macrophages promoted fibroblast proliferation and fibrosis formation in vitro, accompanied with a disorder of the APN/CPT1A pathway, an overproduction of lipid peroxides, and a low level of autophagy in HFL-1 cells. Thereafter, APN treatment or CPT1A overexpression greatly suppressed above lipid peroxide accumulation, fibroblast proliferation, and fibrosis but activated autophagy in vitro. Furthermore, an in vivo IPF rat model was established by injection of bleomycin (BLM). Consistently, CPT1A overexpression exerted a protective role against pulmonary fibrosis in vivo; however, the antifibrosis property of CPT1A was partly abolished by 3-methyladenine (an autophagy inhibitor). In summary, APN/CPT1A-mediated fatty acid metabolism exerted its protective role in IPF partly through activating autophagy, shedding a new prospective for the treatment of IPF.

Comprehensive Analysis of Immune-Related Metabolic Genes in Lung Adenocarcinoma.

Purpose: The immunotherapy of lung adenocarcinoma (LUAD) has received much attention in recent years and metabolic reprogramming is linked to immune infiltration in the tumor microenvironment. Therefore, it is indispensable to dissect the role of immune-related metabolic genes in lung adenocarcinoma. Methods: In this study, we screened immune-related genes by Pearson correlation. The function of these genes was explored by gene ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis. The differently expressed immune-related genes were analyzed by Limma. Furthermore, the LUAD patients were clustered based on immune-related genes through consensus clustering. The Unicox was used to identify survival-immune-related metabolic genes. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was used to optimize the gene sets. A prediction model was constructed and tested. The potential therapeutic target was selected based on two criteria, these immune-related metabolic genes that were highly expressed in tumor tissues and negatively correlated with the survival of patients in LUAD. Quantitative real-time PCR (qRT-PCR) was used for in vitro experimental validations. Results: We identified 346 immune-related genes, mainly involved in arachidonic acid metabolism and peroxisome proliferator-activated receptor (PPAR) signaling. Moreover, a total of 141 immune-related genes were dysregulated between tumor and normal tissues. We clustered three subtypes of LUAD based on immune-related metabolic genes and these subtypes exhibited different survival and immune status. We found Ribonucleotide Reductase Regulatory Subunit M2 (RRM2) as a potential therapeutic target, which is positively correlated with the cyclin-dependent kinase family of genes. Conclusion: We comprehensively analyzed the immune-related metabolic genes in LUAD. RRM2 was determined as a promising metabolic checkpoint for lung adenocarcinoma.

HBO1 induces histone acetylation and is important for non-small cell lung cancer cell growth.

We examined the expression and the potential biological function of HBO1 in non-small cell lung cancer (NSCLC). TCGA and Oncomine databases showed that HBO1 transcripts were elevated in NSCLC. Furthermore, in local NSCLC tumor tissues HBO1 expression was higher than that in matched adjacent lung tissues. In primary and immortalized NSCLC cells, HBO1 shRNA robustly inhibited cell viability, proliferation and migration. Moreover, HBO1 knockout by CRISPR/Cas9 induced significant anti-tumor activity in NSCLC cells. Conversely, ectopic HBO1 overexpression in primary NSCLC cells increased proliferation and migration. H3-H4 histone acetylation and expression of several potential oncogenic genes (CCR2, MYLK, VEGFR2 and OCIAD2) were significantly decreased in NSCLC cells with HBO1 silencing or knockout. They were however increased after HBO1 overexpression. Intratumoral injection of HBO1 shRNA-expressing adeno-associated virus hindered the growth of A549 cell xenografts and primary NSCLC cell xenografts in nude mice. H3-H4 histone acetylation as well as expression of HBO1 and HBO1-dependent genes were decreased in HBO1-silenced NSCLC xenograft tissues. An HBO1 inhibitor WM-3835 potently inhibited NSCLC cell growth. Together, HBO1 overexpression promotes NSCLC cell growth.

Bioinformatic analysis of differentially expressed genes and pathways in idiopathic pulmonary fibrosis.

BACKGROUND: Using bioinformatic methods to explore the differentially expressed genes (DEGs) of human idiopathic pulmonary fibrosis (IPF) and to elucidate the pathogenesis of IPF from the genetic level. METHODS: The GSE110147 gene expression profile was downloaded from the GEO database. The data of lung adenocarcinoma (LUAD) samples, lung squamous cell carcinoma (LUSC) samples and normal samples were downloaded from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. DEGs between IPF patients and healthy donors were analyzed using the GEO2R tool. Use the "clusterprofiler" package in R software to perform gene ontology (GO) and KEGG pathway enrichment analysis, and then perform function annotation and protein-protein interaction (PPI) network construction in the STRING online tool. The Genome Browser tool of the university of california santa cruz (UCSC) online website was used to predict transcription factors (TFs) of genes. In the final, the results were analyzed synthetically. RESULTS: A total of 9,183 DEGs were identified, of which 4,545 genes were down-regulated, and 4638 were up-regulated. MMP1, SPP1, and BPIFB1 were the top three DEGs with the highest significant up-regulation. These DEGs played an important role in the occurrence of IPF through the MAPK (mitogen-activated protein kinase) signaling pathway. Furthermore, 50 DEGs were enriched in the expression of PD-L1 and the PD-1 checkpoint pathway in cancer, of which 11 genes were re-enriched in the pathway of non-small cell lung cancer. The expression of the 11 genes were extensively regulated by CTCFL, SP2 and ZNF341. Most of them were differentially expressed between lung cancers and normal lung tissues. The overall survival (OS) curve of LUAD were significantly stratified by AKT2, KRAS, PIK3R1, meanwhile the OS curve of LUAC was significantly stratified by MAPK3. CONCLUSIONS: Bioinformatics analysis revealed that DEGs including MPP1 might be potential targets and biomarkers of IPF, and the MAPK signaling pathway is related to the occurrence and development of IPF. The development of IPF lung cancer complications may be related to the activation of genes enriched in PD-L1 expression and PD-1 checkpoint pathway, which provides clues to the pathogenesis of IPF combined with lung cancer.

Clinical Characteristics and Prognosis of Patients With Pulmonary Mucoepidermoid Carcinoma: A SEER-Based Analysis.

BACKGROUND: Primary pulmonary mucoepidermoid carcinoma (PMEC) is an extremely rare malignancy. Its clinical characteristics and prognosis are not fully understood. This study evaluated clinical characteristics and prognostic factors of PMEC and established a nomogram to predict its 1-, 3-, 5- and 10-year cancer-specific survival (CSS) rates. METHODS: In the Surveillance, Epidemiology, and End Results database from January 1, 2016 to December 31, 2016, patients pathologically diagnosed with PMEC were identified. Kaplan-Meier analysis and Cox regression were performed to evaluate the CSS stratified by different covariates. A predictive nomogram model was built and validated by the concordance index (C-index) and calibration curves. RESULTS: A total of 585 PMEC patients were identified. A total of 408 (70%) of patients were placed into the training cohort, and 177 (30%) patients were placed into the validation cohort. The 5- and 10-year CSS rates of stage I-II PMEC patients were 91.4 and 88.9, respectively. The 1-, 3- and 5-year CSS rates of stage III-IV PMEC were 56.5, 39.45, and 32.1%, respectively. Survival curves showed that older age, large tumor size, poor differentiation, and high TNM stage were associated with a significantly worse prognosis. CSS outcomes were significantly better in patients who received surgical treatments (surgical alone, surgery plus radiation and/or chemotherapy). Patients who received radiation and/or chemotherapy had the worst prognosis. Multivariate Cox results revealed that covariates, including age, tumor laterality, tumor sizes, pathological differentiation, lymph node metastasis, distant metastasis, TNM stage and therapy, were independent prognostic factors for PMEC. These factors were used to construct a nomogram. The C-index of the nomogram was 0.921. The calibration curve presented favorable consistency between the predicted CSS and actual observations. This nomogram was validated by the validation cohort. The C-index of the validation cohort was 0.968. CONCLUSION: Age, bilateral tumors, tumor size, pathological differentiation grade, lymph node metastasis, distant metastasis, TNM stage and therapy were independent prognostic factors of PMEC patients. The first nomogram for predicting the CSS of PMEC was built and validated, showing its potential value in practice.

Efficacy and safety of pirfenidone in the treatment of idiopathic pulmonary fibrosis patients: a systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES: Idiopathic pulmonary fibrosis (IPF) has been defined as a distinctive type of chronic fibrotic disease, characterised by a progressive decline in lung function and a common histological pattern of interstitial pneumonia. To analyse the efficacy and safety of pirfenidone in the treatment of IPF, a systematic review and meta-analysis was performed. DESIGN: This is a meta-analysis study. PARTICIPANTS: Patients were diagnosed as IPF. INTERVENTIONS: Use of pirfenidone. PRIMARY AND SECONDARY OUTCOME: Progression-free survival (PFS), acute exacerbation and worsening of IPF and Impact on adverse events. MEASURES: The inverse variance method for the random-effects model was used to summarise the dichotomous outcomes, risk ratios and 95% CIs. RESULTS: A total of 9 randomised controlled trials with 1011 participants receiving pirfenidone and 912 controls receiving placebo were summarised. The pooled result suggested a statistically significant difference inall-cause mortality after pirfenidone use, with a summarised relative ratio of 0.51 (p<0.01). Longer PFS was observed in patients receiving pirfenidone compared with those who were given placebo (p<0.01). The IPF groups presented a high incidence of adverse events with a pooled relative ratio of 3.89 (p<0.01). CONCLUSIONS: Pirfenidone can provide survival benefit for patients with IPF. Pirfenidone treatment was also associated with a longer PFS, a lower incidence of acute exacerbation and worsening of IPF.