Apoptosis In Lung Adenocarcinoma Research Articles

Retracted: Human Schlafen 5 Inhibits Proliferation and Promotes Apoptosis in Lung Adenocarcinoma via the PTEN/PI3K/AKT/mTOR Pathway.

[This retracts the article DOI: 10.1155/2021/6628682.].

Activin A induces apoptosis of human lung adenocarcinoma A549 cells through endoplasmic reticulum stress pathway.

Activin A, a member of the transforming growth factor‑β (TGF‑β) superfamily, has been implicated in the tumorigenesis and progression of various cancers. However, it remains unclear whether activin A induces apoptosis in human lung adenocarcinoma cells through the endoplasmic reticulum (ER) stress pathway. In the present study, BrdU, flow cytometry and western blotting were used to examine cell proliferation, apoptosis and protein expression, respectively. The present study revealed that activin A inhibited human lung adenocarcinoma A549 cell proliferation, induced apoptosis, and upregulated the protein levels of C/EBP homologous protein (CHOP), growth arrest and DNA damage‑inducible protein 34 (GADD34), cleaved‑caspase‑3 and caspase‑12. Furthermore, the administration of activin A did not alter the levels of suppressor of mothers against decapentaplegic 3 (Smad3) or phosphorylated (p)‑Smad3 proteins, whereas, it significantly elevated the levels of ActRIIA and p‑extracellular signal regulated kinase proteins 1 and 2 (ERK1/2) proteins in A549 cells. The apoptotic effects of activin A on A549 cells were attenuated by the ERK inhibitor FR180204, which also downregulated CHOP and caspase‑12 protein levels. Additionally, activin A increased intracellular calcium flux in A549 cells, and the calcium ion chelator BAPTA acetoxymethyl ester (BAPTA‑AM) inhibited activin A‑induced A549 cell apoptosis, whereas the calcium agonist ionomycin significantly increased apoptosis of A549 cells induced by activin A. These findings indicated that the activation of the ER stress pathway resulting in apoptosis of A549 cells triggered by activin A is facilitated by the ActRIIA‑ERK1/2 signaling and calcium signaling. The present findings suggest that the agonists of ERK and calcium signaling exhibit promising clinical therapeutic potential for the induction of apoptosis in lung adenocarcinoma.

EP02.03-07 LINC00629 Regulates Cell Proliferation, Migration, Invasion and Apoptosis of Lung Adenocarcinoma

EP02.03-07 LINC00629 Regulates Cell Proliferation, Migration, Invasion and Apoptosis of Lung Adenocarcinoma

Silencing of CD147 inhibits cell proliferation, migration, invasion, lipid metabolism dysregulation and promotes apoptosis in lung adenocarcinoma via blocking the Rap1 signaling pathway

ObjectiveCD147 is an important glycoprotein that participates in the progression of diverse cancers. This study aims to explore the specific function of CD147 in lung adenocarcinoma (LUAD) and to reveal related downstream molecular mechanisms.MethodsFollowed by silencing of CD147, the viability, migration, invasion, and apoptosis of LUAD cells were measured by CCK8, wound healing, transwell assay, and flow cytometer, respectively. The expression of CD147 and two markers of lipid metabolism (FASN and ACOX1) were detected by qRT-PCR. A xenograft tumor model was constructed to investigate the function of CD147 in vivo. Then transcriptome sequencing was performed to explore the potential mechanisms. After measuring the expression of Rap1 and p-p38 MAPK/p38 MAPK by western blot, the changes of CD147 and lipid metabolism markers (FASN, ACOX1) was detected by Immunohistochemistry. Moreover, a Rap1 activator and a Rap1 inhibitor were applied for feedback functional experiments.ResultsCD147 was up-regulated in LUAD cells, and its silencing inhibited cell proliferation, migration, invasion, lipid metabolism dysregulation and promoted apoptosis, while overexpression of CD147 showed the opposite results. Silencing of CD147 also inhibited the growth of tumor xenografts in mice. Transcriptome sequencing revealed 834 up-regulated differentially expressed genes (DEGs) and 602 down-regulated DEGs. After functional enrichment, the Rap1 signaling pathway was selected as a potential target, which was then verified to be blocked by CD147 silencing. In addition, the treatment of Rap1 activator weakened the inhibiting effects of si-CD147 on the proliferation, migration, invasion, and lipid metabolism in LUAD cells, while the intervention of RAP1 inhibitor showed the opposite results.ConclusionsSilencing of CD147 inhibited the proliferation, migration, invasion, lipid metabolism dysregulation and promoted apoptosis of LUAD cells through blocking the Rap1 signaling pathway.

MiR-375 promotes cisplatin sensitivity of lung adenocarcinoma

BackgroundCisplatin-based chemotherapy has been widely used in the treatment of lung adenocarcinoma (LUAD). However, the development of cisplatin resistance becomes a major obstacle impeding the curative effect. It remains necessary to uncover the molecular mechanism of cisplatin resistance. MethodsBased on the CCLE database, lung cancer cell lines were divided into cisplatin-resistant and cisplatin-sensitive groups. The differentially expressed miRNAs were filtered and further identified by survival prognosis analysis. After transfection with miR-375 inhibitor or mimic, cell cytotoxicity assay, flow cytometry and western blot were conducted to validate the role of miR-375. The transcription factor (TF)-miRNA network was constructed based on TransmiR. The target genes of miR-375 were predicted by Starbase and further verified by RT-qPCR and immunohistochemistry results in the Human Protein Atlas. Functional enrichment analysis was performed with GO terms and KEGG. ResultsIn this study, miR-375 showed the ability to promote cisplatin sensitivity and apoptosis of LUAD. Genes correlated with miR-375 in LUAD were analyzed and ABCC8 showed the strongest positive correlation. Moreover, transcription factors that regulate miR-375 expression were predicted. MBNL1, PTPN3, PRKD1 and RPN1 were identified as the target genes of miR-375. Enrichment analysis demonstrated that miR-375-related genes associated with promoting cell proliferation and anti-apoptosis were involved in the MAPK signaling pathway. ConclusionOverall, this study provides new insights into the role of miR-375 in the cisplatin sensitivity of LUAD. Our present findings may serve as a theoretical basis for new therapeutic strategies and predictive models of cisplatin resistance in LUAD.

Association of long noncoding RNA MALAT1 with the radiosensitivity of lung adenocarcinoma cells via the miR-140/PD-L1 axis

ObjectiveTo investigate the effect of MALAT1 on the modulating the radiosensitivity of lung adenocarcinoma, through regulation of the expression of the miR-140/PD-L1 axis. MethodsThe online databases UALCAN and dbDEMC were searched for the MALAT1 and miR-140 expressions in patients with lung adenocarcinoma (LUAD), respectively. Then analyze their relationship with overall survival rates separately in the UALCAN and ONCOMIR databases. A functional analysis was performed for A549 cells by transfecting small-interfering RNAs or corresponding plasmids after radiotherapy. Xenograft models of LUAD exposed to radiation were established to further observe the effects of MALAT1 on the radiosensitivity of LUAD. The luciferase assay and reverse transcription–polymerase chain reaction were performed to assess the interaction between miR-140 and MALAT1 or PD-L1. ResultsMALAT1 were overexpressed in human LUAD tumor tissues and cell lines, while miR-140 were inhibited. MALAT1 knockdown or miR-140 increase suppressed cell proliferation and promoted cell apoptosis in LUAD after irradiation. LUAD xenograft tumor growth was also inhibited by MALAT1 knockdown combined with irradiation. miR-140 could directly bind with MALAT1 or PD-L1. Furthermore, MALAT1 knockdown inhibited PD-L1 mRNA and protein expressions by upregulating miR-140 in LUAD cells. ConclusionMALAT1 may function as a sponge for miR-140a-3p to enhance the PD-L1 expression and decrease the radiosensitivity of LUAD. Our results suggest that MALAT1 might be a promising therapeutic target for the radiotherapy sensitization of LUAD.

Upregulation of LPGAT1 Enhances Lung Adenocarcinoma Proliferation.

Lung adenocarcinoma (LUAD) is one of the leading causes of cancer-related mortality. Lysophosphatidylglycerol acyltransferase (LPGAT1) regulates the biosynthesis of triacylglycerol, which is essential for maintaining phospholipid homeostasis and modulating the structural integrity of mitochondrial membranes. LPGAT1 has been demonstrated to be differentially expressed in normal lung tissue and LUAD tissues, and can serve as a metabolically relevant gene with potential prognostic value. However, the potential role of LPGAT1 in LUAD is still unknown. This study sought to determine the role of LPGAT1 in LUAD progression. LPGAT1 expression was examined in LUAD cells and tumor tissues from LUAD patients. The effect of LPGAT1 was then assessed in both cell and animal models after LPGAT1 was knocked down by RNA interference. LPGAT1 was upregulated in LUAD tissues. Overexpression of LPGAT1 was associated with an unfavorable prognosis in LUAD patients, as revealed by univariate and multivariate Cox analyses. Knockdown of LPGAT1 abrogated tumor growth and proliferation in both cell and animal models. This study demonstrates that LPGAT1 promotes proliferation and inhibits apoptosis in LUAD. Hence, LPGAT1 may provide new treatment strategies for LUAD.

RASGRP2 is a potential immune-related biomarker and regulates mitochondrial-dependent apoptosis in lung adenocarcinoma.

Ras guanine nucleotide-releasing protein 2 (RASGRP2), one of the guanine nucleotide exchange factors (GEFs), has attracted much attention in recent years. However, the correlation between RASGRP2 and immune infiltration and malignant features in lung adenocarcinoma (LUAD) has rarely been mentioned. The Limma package and the LASSO regression model were performed to screen for differentially expressed genes. Data from the TCGA and 5 GEO databases were used to explore the expression level of RASGRP2 in LUAD patients. A weighted co-expression network and LinkFinder module were established to find the related genes of RASGRP2. The ESTIMATE algorithm was used to analyze the correlation between RASGRP2 and immune infiltration in LUAD. Tumor-infiltrating immune cells were sorted and sequenced at the single-cell level to analyze differences in RASGRP2. Real-time PCR and immunohistochemistry were performed in the real-world cohort to verify the expression of RASGRP2 and its correlation with immune-related genes. Clone formation and EdU assays were used to verify the proliferation ability. The proportion of apoptotic cells was analyzed by flow cytometry. Observation of mitochondrial membrane potential (MMP) changes by fluorescence microscopy. Our results suggested that decreased RASGRP2 was associated with worse clinical parameters and prognosis in LUAD patients. And we constructed a FLI1-HSA-miR-1976-RASGRP2 transcriptional network to support the role of RASGRP2. Enrichment analysis revealed that RASGRP2 was involved in lymphocyte activation and leukocyte adhesion. RASGRP2 was found to be positively correlated with the infiltration of most immune cells, immunoregulators, and chemokines in a subsequent study. Meanwhile, the real-world cohort confirmed that the expression levels of PDCD1, CTLA4, CD40LG, CCL14, CXCR5, and CCR7 were higher in the high-RASGRP2 expression group. Cytological experiments proved that RASGRP2 inhibited cell proliferation in LUAD by regulating mitochondrial-dependent apoptosis. RASGRP2 was a potential immune-related biomarker of LUAD. In addition, RASGRP2 was involved in the malignant progression of LUAD through the regulation of mitochondrial-dependent apoptosis.

LncRNA VIM-AS1 acts as a prognostic biomarker and promotes apoptosis in lung adenocarcinoma.

Background: Long non-coding RNA VIM-antisense 1 (VIM-AS1) has been reported that it is involved in the progression of several cancers. However, the aberrant expression profile, clinical significance, and biological function of VIM-AS1in lung adenocarcinoma (LUAD) have not been fully described. We tend to perform a comprehensive analysis to identify the clinical prognostic value of VIM-AS1 for LUAD patients and explore its potential molecular mechanisms in LUAD development. Methods: The expression features of VIM-AS1 in LUAD were identified based on Cancer Genome Atlas database (TCGA) and genotypic tissue expression (GTEx). The LUAD patients' lung tissues were collected to testify above expression features. Survival analysis and COX regression analysis were performed to evaluate the prognostic value of VIM-AS1 in LUAD patients. Then Correlation analysis was performed to filter VIM-AS1 co-expression genes, and their molecular functions were constructed. Furtherly, we constructed the lung carcinoma A549 cell line with VIM-AS1 overexpression to test its effect on cell function. Results: VIM-AS1 expression levels were significantly downregulated in LUAD tissues. VIM-AS1 with low expression is significantly associated with short overall survival (OS), disease-specific survival (DSS), progress free interval (PFI), late T pathological stage, and lymph node metastasis for LUAD patients. The low expression level of VIM-AS1 was an independent risk factor for poor prognosis for LUAD patients. The biological functions of co-expressed genes indicated that VIM-AS1 regulating the apoptosis process may be the potential mechanism for LUAD. Specifically, we testified VIM-AS1 can promote apoptosis in A549 cells. Conclusion: VIM-AS1 was significantly downregulated in LUAD tissues, and it can be a promising prognostic index for LUAD development. VIM-AS1 regulating apoptotic effects may play important roles in LUAD progression.

BDH2 promotes apoptosis and autophagy of lung adenocarcinoma cells via Akt/mTOR pathway.

Cytoprotective autophagy induces tumor cell apoptosis or autophagic programmed cell death. Autophagy and apoptosis are implicated in the pathogenesis of lung cancer, especially lung adenocarcinoma. 3-Hydroxybutyrate dehydrogenase type 2 (BDH2), a rate-limiting catalyzer in the regulation of intracellular iron metabolism and siderophore biogenesis, has been shown to be a tumor suppressor through promotion of cell apoptosis and autophagy. However, the biological role of BDH2 on lung adenocarcinoma cell apoptosis and autophagy remains unclear. Data from Western blot and qRT-PCR showed that BDH2 was down-regulated in lung adenocarcinoma cells (A549, NCI-H1975, PC9) compared to normal human lung cells (BEAS-2B). Functional assays demonstrated that pcDNA-mediated over-expression of BDH2 reduced cell viability of lung adenocarcinoma cells, and repressed the proliferation. Cell apoptosis of lung adenocarcinoma was promoted by BDH2 over-expression with up-regulation of Bax and cleaved caspase-3. Over-expression of BDH2 reduced protein expression of p62 in lung adenocarcinoma cells, enhanced LC3 and Beclin-1. Phosphorylation of AKT and mTOR in lung adenocarcinoma cells were reduced by BDH2 over-expression. In conclusion, BDH2 functioned as a tumor suppressor in lung adenocarcinoma through promotion of Akt/mTOR-mediated cell apoptosis and autophagy.

High level of LncRNA MAPKAPK5-AS1 predicts poor prognosis and contributes to the malignant proliferation and EMT of non-small cell lung cancer via sponging miR-490-3p from HMGB2.

Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD). To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC. The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model. The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo. Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.

Identifying Immune Cell Infiltration and Effective Diagnostic Biomarkers in Lung Adenocarcinoma by Comprehensive Bioinformatics Analysis and In Vitro Study.

Family with sequence similarity 72B (FAM72B) has been characterized in the regulation of neuronal development. Nevertheless, the prognostic value of FAM72B expression and its function in the immune microenvironment of lung adenocarcinoma (LUAD) currently remains elusive. In this study, by adopting bioinformatics methodology and experimental verification, we found that FAM72B was upregulated in lung cancer tissues and cell lines, and a higher FAM72B level predicted an unfavorable clinical outcome in LUAD patients. The knockdown of FAM72B significantly inhibited cell proliferation, cell migration, and induced cell apoptosis in LUAD. The receiver operating characteristic curve suggested that FAM72B had a high predictive accuracy for the outcomes of LUAD. Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analyses confirmed that FAM72B-related genes were involved in cell proliferation and immune-response signaling pathway. Moreover, upregulated FAM72B expression was significantly associated with immune cell infiltration in the LUAD tumor microenvironment. Meanwhile, a potential ceRNA network was constructed to identify the lncRNA-AL360270.2/TMPO-AS1/AC125807.2/has-let-7a/7b/7c/7e/7f/FAM72B regulatory axis that regulates FAM72B overexpression in LUAD and is associated with a poor prognosis. We also confirmed that AL360270.2, TMPO-AS1, and AC125807.2 were significantly upregulated in LUAD cell lines than in human bronchial epithelial cells. In conclusion, FAM72B may serve as a novel biomarker in predicting the clinical prognosis and immune status for lung adenocarcinoma.

Chromobox Homologue 7 Acts as a Tumor Suppressor in Both Lung Adenocarcinoma and Lung Squamous Cell Carcinoma via Inhibiting ERK/MAPK Signaling Pathway.

Chromobox homologue 7 (CBX7) is a member of the polycomb group family that plays a pivotal role in regulating cellular processes in human cancers. This study aims to explore the function and underlying molecular mechanisms of CBX7 in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). The expression of CBX7 in LUAD and LUSC tissues was analyzed by UALCAN and GEPIA based on the TCGA database. Cell viability and apoptosis were measured by CCK-8 and flow cytometry assays, respectively. Cell migration and invasion were detected by transwell assay. The functions of downregulated genes in LUAD were enriched via GO and KEGG pathway analyses. The mRNA expression of CBX7, ERK1/2, and p38 was determined by qRT-PCR, and the protein levels of CBX7, ERK1/2, p-ERK1/2, p38, and p-p38 were measured by Western blotting. Tumor xenograft model was established to validate the antitumor effect of CBX7. The expression of CBX7 and Ki-67 in tumor tissues was detected by immunohistochemistry. CBX7 was downregulated in the tissues and cells of both LUAD and LUSC. Low CBX7 expression was associated with a poor overall survival rate in LUAD patients. CBX7 overexpression inhibited the viability, migration, and invasion and promoted the apoptosis of LUAD and LUSC cells. In addition, the downregulated genes in LUAD were enriched in MAPK cascade (GO) and MAPK signaling pathway (KEGG). ERK/MAPK pathway was then determined as a downstream target of CBX7, which was inhibited by CBX7 overexpression in LUAD and LUSC cells. The overexpression of CBX7 inhibited the malignant progression of LUAD and LUSC cells probably via suppressing the ERK/MAPK signaling pathway in vitro and in vivo.

Circ_0001998 Regulates the Proliferation, Invasion, and Apoptosis of Lung Adenocarcinoma via Sponging miR-145.

Circular RNA (circRNA) is considered an important regulator of cancer. Circ_0001998 is a newly discovered circRNA and its role in lung adenocarcinoma (LUAD) remains obscure and requires further study. The expression levels of circ_0001998 and miR-145 in LUAD were predicted by bioinformatics analysis and then verified by qRT-PCR in the LUAD cell lines. CCK-8, clone formation, EdU assay, and flow cytometry were applied to determine the effects of silencing circ_0001998 on the viability, proliferation, and apoptosis of LUAD cells. The target relationship between circ_0001998 and miR-145 was predicted by bioinformatics analysis and verified by a luciferase activity experiment. The effect of circ_0001998/miR-145 axis on the viability, proliferation, and apoptosis of LUAD cells was verified by the rescue experiment. Circ_0001998 was upregulated in LUAD, and silencing circ_0001998 suppressed viability, proliferation, and invasion of LUAD cells. The target gene of circ_0001998, miR-145, was downregulated in LUAD, and the low expression of miR-145 indicated a poor prognosis. The effect of silencing circ_0001998 on the biological function of LUAD cells was reversed by the miR-145 inhibitor. Circ_0001998 regulates the proliferation, invasion, and apoptosis of LUAD via sponging miR-145.

Deciphering the Role of Shugoshin-Like Protein 1 in Lung Adenocarcinoma: A Comprehensive Analysis and In Vitro Study.

Shugoshin-like protein 1 (SGO1) has been characterized in its function in correct cell division and its role in centrosome cohesion in the nucleus. However, the underlying biological function and potential mechanisms of SGO1 driving the progression of lung adenocarcinoma remain unclear. In this study, we found that SGO1 was increased in LUAD tissues and cell lines. Upregulation of SGO1 expression was correlated with poor overall survival (OS), disease-free survival (DSS), and progression-free survival (PFS) in patients with LUAD. ROC curve analysis suggested that the AUC value of SGO1 was 0.983. Correlation analysis showed that SGO1 expression was related to immune infiltration in LUAD. Meanwhile, a potential ceRNA network was constructed to identify the lncRNA-MIR4435-2HG/miR-125a-5p/SGO1 regulatory axis in LUAD. Finally, we determine that SGO1 regulated the cell proliferation and cell apoptosis of lung adenocarcinoma in vitro. In conclusion, our data suggested that SGO1 could be a novel prognostic biomarker for lung adenocarcinoma.

CircRNA6783 Inhibits Cell Proliferation and Promotes Apoptosis in Lung Adenocarcinoma.

PurposeCircular RNA (circRNA) serves an important role in tumour genesis and development. But, little is known about its role in lung adenocarcinoma (LA). This study aimed to investigate circRNA6783 expression in peripheral whole blood (PWB) of LA and controls and explore its effect on proliferation and apoptosis in human lung adenocarcinoma cells (LAC).Patients and MethodsThe levels of circRNA6783 in LA cell lines and peripheral whole blood (PWB) of 40 patients and 30 controls were detected by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). In order to explore the effect of circRNA6783 on LA behavior, we overexpressed circRNA6783 in NCI-H1975 cells. The impact on the proliferation of tumor cells was then examined by Cell Counting Kit 8 (CCK8) assay, and the effects on apoptosis in the cell line were detected using flow cytometry.ResultsThe expression levels of circRNA6783 were significantly higher in LA cell lines and PWB (P < 0.05). The diagnostic value of the area under the receiver operating characteristic curve (AUC) was 0.830, with a sensitivity of 60% and specificity of 96.7%. In addition, functional experiments showed that overexpression of circRNA6783 restrained cell proliferation, significantly increased spontaneous apoptosis.ConclusionCircRNA6783 was upregulated in LA PWB. In vitro assessment demonstrated that circRNA6783 could act as a potential biomarker for LA diagnosis.

Knockdown of mitochondrial threonyl-tRNA synthetase 2 inhibits lung adenocarcinoma cell proliferation and induces apoptosis

ABSTRACT Lung cancer is a significant global burden. Aminoacyl-tRNA synthetases (aaRSs) can be reliably identified by the occurrence and improvement of tumors. Threonyl-tRNA synthetase (TARS) and mitochondrial threonyl-tRNA synthetase 2 (TARS2) are both aaRSs. Many studies have shown that TARS are involved in tumor angiogenesis and metastasis. However, TARS2 has not yet been reported in tumors. This study explored the role of TARS2 in the proliferation and apoptosis of lung adenocarcinoma (LUAD). TARS2 expression in lung adenocarcinoma and non-cancerous lung tissues was detected via immunohistochemistry. Cell proliferation was detected using MTS, clone formation, and EdU staining assays. Flow cytometry was used to detect cell cycle, mitochondria reactive oxygen species (mROS) production, and apoptosis. Mitochondrial membrane potential (MMP ΔΨm) was detected using JC-1 fluorescent probes. Cell cycle, apoptosis-related pathway, and mitochondrial DNA (mtDNA) -encoded protein expression was detected via Western blotting. Finally, the effect of TARS2 on tumor growth was examined using a xenotransplanted tumor model in nude mice. We found that TARS2 was highly expressed in lung adenocarcinoma tissues and associated with poor overall survival (OS). Mechanistic analysis showed that knockdown of TARS2 inhibited proliferation through the retinoblastoma protein (RB) pathway and promoted mROS-induced apoptosis. Knockdown of TARS2 inhibits tumor growth in a xenotransplanted tumor model. TARS2 plays an important role in LUAD cell proliferation and apoptosis and may be a new therapeutic target.

Transmembrane p24 trafficking protein 2 regulates inflammation through the TLR4/NF-\u03baB signaling pathway in lung adenocarcinoma

BackgroundTo investigate the role of transmembrane p24 trafficking protein 2 (TMED2) in lung adenocarcinoma (LUAD) and determine whether TMED2 knockdown could inhibit LUAD in vitro and in vivo.MethodsTIMER2.0, Kaplan-Meier plotter, gene set enrichment analysis (GSEA), Target Gene, and pan-cancer systems were used to predict the potential function of TMED2. Western blotting and immunohistochemistry were performed to analyze TMED2 expression in different tissues or cell lines. The proliferation, development, and apoptosis of LUAD were observed using a lentivirus-mediated TMED2 knockdown. Bioinformatics and western blot analysis of TMED2 against inflammation via the TLR4/NF-κB signaling pathway were conducted.ResultsTMED2 expression in LUAD tumor tissues was higher than that in normal tissues and positively correlated with poor survival in lung cancer and negatively correlated with apoptosis in LUAD. The expression of TMED2 was higher in tumors or HCC827 cells. TMED2 knockdown inhibited LUAD development in vitro and in vivo and increased the levels of inflammatory factors via the TLR4/NF-κB signaling pathway. TMED2 was correlated with TME, immune score, TME-associated immune cells, their target markers, and some mechanisms and pathways, as determined using the TIMER2.0, GO, and KEGG assays.ConclusionsTMED2 may regulate inflammation in LUAD through the TLR4/NF-κB signaling pathway and enhance the proliferation, development, and prognosis of LUAD by regulating inflammation, which provide a new strategy for treating LUAD by regulating inflammation.

Exosomes from M1-polarized macrophages promote apoptosis in lung adenocarcinoma via the miR-181a-5p/ETS1/STK16 axis.

Serine/threonine kinase 16 (STK16) is crucial in on regulating tumor cell proliferation, apoptosis, and prognosis. Activated M1 macrophages regulate lung adenocarcinoma (LUAD) growth by releasing exosomes. This study aims to investigate the role of STK16 and then focus on the possible mechanisms through which exosomes derived from M1 macrophages play their roles in LUAD cells by targeting STK16. Clinical LUAD samples were used to evaluate the expression of STK16 and its association with prognosis. Exosomes were isolated from M0 and M1 macrophages by ultracentrifugation and were then identified by electron microscopy and western blotting. In vitro gain‐ and loss‐of‐function experiments with LUAD cells were performed to elucidate the functions of miR‐181a‐5p, ETS1, and STK16, and mouse xenograft models were used to verify the function of STK16 in vivo. Western blotting, quantitative real‐time PCR, CCK‐8 assay, cell apoptosis, immunohistochemistry staining, luciferase assay, ChIP assay, and bioinformatics analysis were performed to reveal the underlying mechanisms. High expression of STK16 was observed in LUAD tissues and cells, and higher expression of STK16 was associated with worse prognosis. Silencing STK16 expression inhibited cell proliferation and promoted apoptosis via the AKT1 pathway. Exosomes from M1 macrophages inhibited viability and promoted apoptosis by inhibiting STK16. Moreover, miR‐181a‐5p is the functional molecule in M1 macrophage‐derived exosomes and plays a vital role in inhibiting cell proliferation and promoting apoptosis by targeting ETS1 and STK16. Hence, exosomes derived from M1 macrophages were capable of inhibiting viability and promoting apoptosis in LUAD via the miR‐181a‐5p/ETS1/STK16 axis.

ETV4 mediated lncRNA C2CD4D-AS1 overexpression contributes to the malignant phenotype of lung adenocarcinoma cells via miR-3681-3p/NEK2 axis

ABSTRACT Lung adenocarcinoma (LUAD) is originated from the mucus-producing glands of the lungs. The involvement of long noncoding RNAs (lncRNAs) has been discovered in multiple diseases. In the present research, we aimed to unmask the role of C2CD4D and THEM5 antisense RNA 1 (C2CD4D-AS1) in LUAD. RT-qPCR or western blot analysis was respectively applied in the detection of RNA or protein expressions. The function of C2CD4D-AS1 in LUAD was assessed by functional assays. Through ChIP, RNA pull down, DNA pull down, RIP and luciferase reporter assays, the in-depth regulatory mechanism of C2CD4D-AS1 in LUAD was explored. C2CD4D-AS1 was dramatically overexpressed in LUAD tissues and cell lines. As a result, depletion of C2CD4D-AS1 significantly repressed cell proliferation, migration, invasion and stimulated cell apoptosis in LUAD. Mechanistically, ETS variant transcription factor 4 (ETV4) activated the transcription of C2CD4D-AS1 and stimulated its up-regulation in LUAD cells, thus affecting LUAD cell biological functions. Furthermore, C2CD4D-AS1 sponged microRNA-3681-3p (miR-3681-3p) and regulated NIMA-related kinase 2 (NEK2), thus participating in modulating LUAD cell biological behaviors. To conclude, C2CD4D-AS1 up-regulation induced by ETV4 enhanced NEK2 expression by sequestering miR-3681-3p to contribute to the malignant behaviors of LUAD cells.