Identification and validation of LINC01322 as a potential prognostic biomarker and oncogene promoting tumor progression in lung adenocarcinoma.

Our study identified a novel long noncoding RNA, LINC01322, that acts as an oncogene in lung adenocarcinoma progression. Cytoplasmic and nuclear RNA purification assays indicated that LINC01322 was localized in the cytoplasm and nucleus. Gene set enrichment analysis revealed the involvement of LINC01322 in the regulation of cell proliferation, migration, and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. LINC01322 may promote lung adenocarcinoma proliferation and migration through the Janus kinase/signal transducer and activator of transcription signaling pathway. In vitro experiments demonstrated that the knockdown of LINC01322 significantly suppressed lung adenocarcinoma cell proliferation, migration, and activation of the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway, whereas overexpression had the opposite effects. Inhibition of the Janus kinase 2/signal transducer and activator of transcription 3 pathway activity partially reversed the enhancement of cell proliferation and migration caused by LINC01322 overexpression. In vivo experiments further verified the oncogene role of LINC01322. Altogether, our findings suggest that LINC01322 promotes lung adenocarcinoma progression by activating the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway and that it could be a therapeutic target.

STMN1 Promotes Tumor Metastasis in Non-small Cell Lung Cancer Through Microtubule-dependent And Nonmicrotubule-dependent Pathways.

The relationship between STMN1 and cancer metastasis is controversial. The purpose of this study was to explore the role and mechanism of STMN1 in NSCLC metastasis. In this study, we reported that STMN1 was highly expressed in NSCLC tissues and associated with poor prognosis. Both in vivo and in vitro functional assays confirmed that STMN1 promoted NSCLC metastasis. Further studies confirmed that STMN1 promoted cell migration by regulating microtubule stability. The results of Co-IP and LC‒MS/MS illustrated that STMN1 interacts with HMGA1. HMGA1 decreases microtubule stability by regulating the phosphorylation level of STMN1 at Ser16 and Ser38 after interacting with STMN1. This result suggested that STMN1 could be activated by HMGA1 to further promote NSCLC metastasis. Meanwhile, it has been found that STMN1 could promote cell migration by activating the p38MAPK/STAT1 signaling pathway, which is not dependent on microtubule stability. However, activating p38MAPK can decrease microtubule stability by promoting the dephosphorylation of STMN1 at ser16. A positive feedback loop was formed between STMN1 and p38MAPK to synergistically promote cell migration. In summary, our study demonstrated that STMN1 could promote NSCLC metastasis through microtubule-dependent and nonmicrotubule-dependent mechanisms. STMN1 has the potential to be a therapeutic target to inhibit metastasis.

Essential role for STAT3/FOXM1/ATG7 signaling-dependent autophagy in resistance to Icotinib.

BACKGROUND: The contribution of autophagy to cancer therapy resistance remains complex, mainly owing to the discrepancy of autophagy mechanisms in different therapy. However, the potential mechanisms of autophagy-mediated resistance to icotinib have yet to be elucidated. METHODS: The effect of autophagy in icotinib resistance was examined using a series of in vitro and in vivo assays. The results above were further verified in biopsy specimens of lung cancer patients before and after icotinib or gefitinib treatment. RESULTS: Icotinib increased ATG3, ATG5, and ATG7 expression, but without affecting Beclin-1, VPS34 and ATBG14 levels in icotinib-resistant lung cancer cells. Autophagy blockade by 3-MA or silencing Beclin-1 had no effects on resistance to icotinib. CQ effectively restored lung cancer cell sensitivity to icotinib in vitro and in vivo. Notably, aberrantly activated STAT3 and highly expressed FOXM1 were required for autophagy induced by icotinib, without the involvement of AMPK/mTOR pathway in this process. Alterations of STAT3 activity using genetic and/or pharmacological methods effectively affected FOXM1 and ATG7 levels increased by icotinib, with altering autophagy and icotinib-mediated apoptosis in resistant cells. Furthermore, silencing FOXM1 impaired up-regulated ATG7 induced by STAT3-CA and icotinib. STAT3/FOXM1 signalling blockade also reversed resistance to icotinib in vivo. Finally, we found a negative correlation between STAT3/FOXM1/ATG7 signalling activity and epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) treatment efficacy in patients undergoing EGFR-TKIs treatment. CONCLUSIONS: Our findings support that STAT3/FOXM1/ATG7 signalling-induced autophagy is a novel mechanism of resistance to icotinib, and provide insights into potential clinical values of ATG7-dependent autophagy in icotinib treatment.

DDX47 promotes cell proliferation and migration in lung adenocarcinoma.

This study aimed to investigate the role of DEAD-box helicase 47 (DDX47) in lung adenocarcinoma (LUAD). Our results demonstrated that DDX47 was highly expressed in LUAD tissues, and its high expression predicted a poor prognosis. Bioinformatics analysis indicated that DDX47 involved RNA processing and cell division. Furthermore, knockdown of DDX47 reduced cell proliferation and migration in vitro. In sum, our data confirmed the cancer-promoting effect of DDX47.

[LINC00668 is Highly Expressed in Lung Squamous Cell Carcinoma and 
Promotes Tumor Cell Migration and Invasion].

BACKGROUND: A lack of effective treatment for lung squamous cell carcinoma (LUSC) makes it an important factor restricting the 5-year survival rate of non-small cell lung cancer (NSCLC). Long non-coding RNA 00668 (LINC00668) was reported to play crucial regulatory roles in the tumorigenesis and progression of various cancers; however, its role in LUSC is unclear. The aim of this study was to investigate the prognosis value and biological function of LINC00668 in NSCLC, especially in LUSC. METHODS: The expression pattern of LINC00668 and its relationship with clinical characteristics and prognosis of patients were investigated in the NSCLC especially LUSC based on The Cancer Genome Altas (TCGA) database. Its function in LUSC cells was explored in vitro. RESULTS: LINC00668 expression was significantly up-regulated in LUSC patients and high expression level of LINC00668 was associated with advanced tumor-node-metastasis (TMN) stage. Moreover, the expression of LINC00668 significantly increased in smoking patients, and was a prognostic indicator for overall survival (OS) of smoking patients with LUSC. In vitro experiments showed that LINC00668 has significantly higher expression level in LUSC cell lines and tissues compared to normal bronchial epithelial cell and para-tumor tissues; meanwhile, functional assay indicated knockdown of LINC00668 effectively inhibited the migration and invasion of LUSC cells. CONCLUSIONS: LINC00668 might closely relate to the development of LUSC, and inhibition of LINC00668 may reduce the metastasis of LUSC.

Overexpression of BCCIP predicts an unfavorable prognosis and promotes the proliferation and migration of lung adenocarcinoma.

BACKGROUND: Lung cancer accounts for the highest rate of cancer-related diagnosis and mortality. Lung adenocarcinoma (LUAD) is the most common histopathological type. BCCIP was originally identified as a BRCA2 and CDKN1A interacting protein. In different cancers, BCCIP plays different roles. The role of BCCIP in LUAD is still unknown. METHODS: The expression and prognostic value of BCCIP was analyzed using public databases, including LCE, GEPIA, TCGA, and clinical specimens. Bioinformatic analysis and vitro experiments were conducted to explore the biological functions of BCCIP in LUAD. By using the GEPIA and TIMER databases, we investigated the correlations between LUAD expression and immune infiltration in LUAD. RESULTS: Compared with normal tissue, LUAD tissue had a higher expression level of BCCIP and high expression level of BCCIP was detrimental to LUAD patient survival. The suppression of BCCIP inhibited LUAD cell proliferation, migration and resulted in G1/S phase arrest in vitro. Bioinformatic analysis demonstrated that BCCIP could be associated with cell cycle, DNA repair and E2F transcription factor family. There were significant correlations between BCCIP expression and immune infiltrates, including B cell, CD4+ T cell, macrophage, neutrophil and dendritic cells. Furthermore, BCCIP expression showed strong correlations with diverse immune marker sets in LUAD, such as B cell, macrophage and DC. CONCLUSIONS: Overexpression of BCCIP predicts an unfavorable prognosis and promotes the proliferation and migration of lung adenocarcinoma cells. BCCIP is correlated with immune infiltration in LUAD. Suppression of BCCIP may be a potential approach in the prevention and treatment of LUAD.

CircPVT1 promotes proliferation of lung squamous cell carcinoma by binding to miR-30d/e.

BACKGROUND: Circular RNAs (circRNAs) are a new type of extensive non-coding RNAs that regulate the activation and progression of different human diseases, including cancer. However, information on the underlying mechanisms and clinical significance of circRNAs in lung squamous cell carcinoma (LUSC) remains scant. METHODS: The expression profile of RNAs in 8 LUSC tissues, and 9 healthy lung tissues were assayed using RNA sequencing (RNA-seq) techniques. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to profile the expression of circPVT1 and its relationship with the prognosis of LUSC, i.e., survival analysis. Moreover, in vitro and in vivo experiments were performed to evaluate the impacts of circPVT1 on the growth of tumors. RNA pull-down tests, mass spectrometry, dual-luciferase reporter assessment, and RNA immune-precipitation tests were further conducted to interrogate the cross-talk between circPVT1, HuR, or miR-30d/e in LUSC. RESULTS: Our data showed that circPVT1 was upregulated in LUSC tissues, serum, and cell lines. LUSC patients with higher circPVT1 expression exhibited shorter survival rates. The in vivo and in vitro data revealed that circPVT1 promotes the proliferation of LUSC cells. Additionally, mechanistic analysis showed that HuR regulated circPVT1. On the other hand, circPVT1 acted as a competing endogenous RNA (ceRNA) of miR-30d and miR-30e in alleviating the suppressive influences of miR-30d and miR-30e on its target cyclin F (CCNF). CONCLUSION: CircPVT1 promotes LUSC progression via HuR/circPVT1/miR-30d and miR-30e/CCNF cascade. Also, it acts as a novel diagnostic biomarker or treatment target of individuals diagnosed with LUSC.

Long noncoding RNA LMO7DN inhibits cell proliferation by regulating the cell cycle in lung adenocarcinoma.

In our previous study, we reported that the long noncoding RNA, LMO7 downstream neighbor (LMO7DN), has a strong prognostic value in lung adenocarcinoma (LUAD). In this study, we further investigated the role of LMO7DN in LUAD progression. LMO7DN was found to be expressed at low levels in LUAD tissues, and its high expression predicted good prognosis. Bioinformatics analysis indicated that LMO7DN was closely associated with the cell cycle. Furthermore, we found that cell proliferation was significantly enhanced following knockdown of LMO7DN, and the number of cells in the G2/M phase was markedly decreased, whereas there was no change in apoptosis. Thus, LMO7DN inhibits cell proliferation by affecting the cell cycle and is of significant prognostic value in LUAD.

Erratum: Long non-coding RNA LINC01116 is overexpressed in lung adenocarcinoma and promotes tumor proliferation and metastasis.

[This corrects the article on p. 4302 in vol. 12, PMID: 32913506.].

Long non-coding RNA LINC01116 is overexpressed in lung adenocarcinoma and promotes tumor proliferation and metastasis.

Long non-coding RNA LINC01116 is involved in the occurrence and progression of a variety of cancers. However, the specific role of LINC01116 in lung adenocarcinoma (LUAD) remains unclear. In this work, we found that LINC01116 was overexpressed in LUAD tissues and cell lines and that increased expression was significantly associated with worse prognoses in patients with LUAD. Univariate and multivariate Cox regression analyses indicated that LINC01116 was an independent risk factor for the prognosis of patients with LUAD. Downregulation of LINC01116 significantly inhibited cell proliferation and migration, promoted cell apoptosis, and prevented cell progression from G1 to S phase. In addition, downregulation of LINC01116 significantly inhibited the epithelial-mesenchymal transition, leading to an increased expression of the epithelial marker E-cadherin and decreased expression of the mesenchymal markers N-cadherin and vimentin. In summary, our results suggest that LINC01116 may act as an oncogene in LUAD and may be a valuable prognostic biomarker for patients with LUAD.

Identification and validation of tumor microenvironment-related genes of prognostic value in lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is a major subtype of non-small cell lung cancer. Despite significant progress in its diagnosis and treatment, the mortality and morbidity rate of LUAD remains high worldwide. The aim of the present study was to perform a systematic investigation of the tumor microenvironment (TME) and identify TME-related genes of prognostic value in patients with LUAD. Firstly, the immune scores and stromal scores of patients with LUAD from The Cancer Genome Atlas were calculated using the Estimation of STromal and Immune cells in MAlignant Tumors using Expression data algorithm, and a total of 281 prognostic TME-related genes were identified. Subsequently, functional analysis and protein-protein interaction network analysis revealed that these genes were mainly related to immune response, inflammatory response and chemotaxis. Finally, two independent LUAD cohorts from the Gene Expression Omnibus database were used to validate these genes, and 4 genes (GTPase IMAP family member 1, T-cell surface glycoprotein CD1b, integrin alpha-L and leukocyte surface antigen CD53) were identified, and downregulation of these genes was indicated to be associated with poor overall survival rate in patients with LUAD. In conclusion, a comprehensive analysis of TME was performed and 4 prognostic TME-related genes in patients with LUAD were identified.

Hydroxychloroquine suppresses lung tumorigenesis via inducing FoxO3a nuclear translocation through STAT3 inactivation.

BACKGROUND: Hydroxychloroquine exhibits synergistic anticancer properties as an adjuvant. However, the role and molecular mechanisms underlying of HCQ as monotherapy for lung adenocarcinoma (LUAD) have yet to be elucidated. METHODS: We assessed the antitumor effects of HCQ in LUAD cells through a series of in vitro and in vivo assays. GEO database and R packages were used to predict molecular mechanisms of HCQ in the treatment of lung adenocarcinoma, followed by verification of gene expression and subcellular localization via immunoblotting, immunofluorescent and immunohistochemistry assays. RESULTS: We showed the phenotypic effects that HCQ inhibited cell growth, induced apoptosis and cell cycle arrest at G1/S transition in A549 and PC-9 cells, which was associated with inhibition of CDK2, CDK4, CyclinD1 and CyclinE, but up-regulation of p21 and p27Kip1. Bioinformatic analysis predicted that 63 targets related to HCQ and LUAD were mainly enriched in JAK-STAT and FoxO pathways. Then, we observed that HCQ decreased the phosphorylation of STAT3, but increased the expression of FoxO3a and its accumulation in the nucleus. The specific STAT3 inhibitor cryptotanshinon augmented the HCQ-induced upregulation and nuclear translocation of FoxO3a. In addition, HCQ increased the expression of p27Kip1, which was impaired by FoxO3a blockade with siRNA. Finally, ablation of p27Kip1 expression abrogated the cytotoxicity of HCQ. More importantly, similar results were further confirmed in vivo. CONCLUSIONS: Taken together, this study suggests that STAT3/FoxO3a/p27Kip1 signaling pathway is involved in the anticancer effects of HCQ, and provides preliminary evidence for therapeutic prospects of HCQ alone in LUAD.

A five-long non-coding RNA signature with the ability to predict overall survival of patients with lung adenocarcinoma.

An increasing number of studies have indicated that the abnormal expression of certain long non-coding RNAs (lncRNAs) is linked to the overall survival (OS) of patients with lung adenocarcinoma (LUAD). The aim of the present study was to establish an lncRNA signature to predict the survival of patients with LUAD. The gene expression profiles and associated clinical information of patients with LUAD were downloaded from The Cancer Genome Atlas database. The cohort was randomly sub-divided into training and verification cohorts. Univariate Cox regression analysis was performed on differentially expressed lncRNAs in the training cohort to select candidate lncRNAs closely associated with survival. Next, a risk score (RS) model consisting of 5 lncRNAs was established by multivariate Cox regression analysis on candidate lncRNAs. Using the median RS obtained from the training cohort as a cut-off point, patients were classified into high- and low-risk groups. Kaplan-Meier survival analysis revealed a significant difference in OS between high- and low-risk groups. The survival prediction ability of the 5-lncRNA signature was further tested in the verification and total cohorts. The results proved that the 5-lncRNA signature had good reliability and stability in survival prediction for patients with LUAD. The univariate Cox regression analysis for the 5-lncRNA signature in each cohort indicated that the 5-lncRNA signature was closely associated with survival. Multivariate Cox regression analysis and stratification analysis proved that the prognostic signature was an independent predictor of survival for patients with LUAD. In addition, functional enrichment analysis indicated that the 5 prognostic lncRNAs may be involved in the tumorigenesis of LUAD through cancer-associated pathways and biological processes. Taken together, the present study provided a 5-lncRNA signature that may serve as an independent survival predictor for patients with LUAD.

Five genes may predict metastasis in non-small cell lung cancer using bioinformatics analysis.

Lung cancer is one of the most common types of malignancy worldwide. The prognosis of lung cancer is poor, due to the onset of metastases. The aim of the present study was to examine lung cancer metastasis-associated genes. To identify novel metastasis-associated targets, our previous study detected the differentially expressed mRNAs and long non-coding RNAs between the large-cell lung cancer high-metastatic 95D cell line and the low-metastatic 95C cell line by microarray assay. In the present study, these differentially expressed genes (DEGs) were analyzed via bioinformatics methods, including Gene Ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. A protein-protein interaction network was subsequently constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins online database and Cytoscape software, and 17 hub genes were screened out on the basis of connectivity degree. These hub genes were further validated in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) using the online Gene Expression Profiling Interactive Analysis database. A total of seven hub genes were identified to be significantly differentially expressed in LUAD and LUSC. The prognostic information was detected using Kaplan-Meier plotter. As a result, five genes were revealed to be closely associated with the overall survival time of patients with lung cancer, including phosphoinositide-3-kinase regulatory subunit 1, FYN, thrombospondin 1, nonerythrocytic α-spectrin 1 and secreted phosphoprotein 1. In addition, lung cancer and adjacent lung tissue samples were used to validate these hub genes by reverse transcription-quantitative polymerase chain reaction. In conclusion, the results of the present study may provide novel metastasis-associated therapeutic strategies or potential biomarkers in non-small cell lung cancer.

Elevated N-telopeptide as a potential diagnostic marker for bone metastasis in lung cancer: A meta-analysis.

BACKGROUND: Growing evidence indicates that the cross-linked N-telopeptide of type I collagen (NTx) is likely to be involved in the development of bone metastasis among lung cancer patients. We perform a meta-analysis to disclose the correlation between bone metastasis and NTx and also to evaluate its value in diagnosis of bone metastasis (BM) in lung cancer. METHOD: Electronic databases were searched and calculated the weighted mean difference (WMD) with 95% confidence interval (CI) to assess the expression difference of NTx between BM+ and BM- lung cancer patients. Moreover, we conducted a sensitivity and specificity test and drew a summary receiver operating characteristic curve (SROC) to assess the diagnostic value of NTx in discerning bone metastasis. RESULTS: A total of eleven studies with 1108 individuals were included in this analysis. The results showed an increased NTx was correlated with the incidence of lung cancer (P < 0.001). The overall sensitivity and specificity of serum NTx (sNTx) for discerning bone metastasis was 0.74 (95% CI = 0.67 to 0.79) and 0.85 (95% CI = 0.80 to 0.89), respectively. As for urine NTx (uNTx) the pooled sensitivity and specificity was 0.77(95% CI = 0.67 to 0.86) and 0.81(95% CI = 0.76 to 0.86). The area under the SROC curve was 0.8889(SE = 0.0255) and 0.8655(SE = 0.0254) for sNTx and uNTx respectively. CONCLUSIONS: The elevation of NTx in lung cancer was positively related with the development and progression of bone metastasis. A higher specificity over sensitivity of NTx suggested that it is a more accurate biomarker to distinguish patients without bone metastasis. Regarding SROC curve, sNTx may be a better choice.