Abnormal methylation mediated upregulation of LINC00857 boosts malignant progression of lung adenocarcinoma by modulating the miR-486-5p/NEK2 axis.

LINC00857 is frequently dysregulated in varying cancers, which in turn exerts carcinogenic effects; however, its DNA methylation status in promoter region and molecular mechanisms underlying the progression of lung adenocarcinoma (LUAD) remain rarely understood. Through bioinformatics analysis, we examined the expression state and methylation site of LINC00857 in LUAD and further investigated the properties of LINC00857 as a competitive endogenous RNA in the cancer progression. The current study revealed that the overexpression of LINC00857 in LUAD tissue and cells was mainly caused by the hypomethylation of the promoter region. LINC00857 knockdown prominently reduced cell proliferation, impeded cell migration and invasion, and restrained lymph node metastasis, with enhancing radiosensitivity. The effects of LINC00857 on tumor growth were also investigated in nude mice models. Subsequently, the downstream factors, miR-486-5p and NEK2, were screened, and the putative regulatory axis was examined. Overall, the regulatory effect of methylation-mediated LINC00857 overexpression on miR-486-5p/NEK2 axis may be a new mechanism for LUAD progression.

Fu H ，Zhang M ，Liu X ，Yang Y ，Xing Y ... -  《-》

Long Non-Coding RNA LINC01116 Promotes the Proliferation of Lung Adenocarcinoma by Targeting miR-9-5p/CCNE1 Axis.

Long non-coding RNA (lncRNA) LINC01116 is crucial in promoting cell proliferation, invasion and migration in solid tumours, including lung adenocarcinoma (LUAD). LINC01116 acts as a competing endogenous RNAs (ceRNA) that binds competitively to microRNAs and plays a critical role in tumour migration and invasion. However, other mechanisms of action besides the ceRNA theory have been rarely reported and remain to be elucidated further. The differences in RNA and protein levels in cells and tissues were assessed through real-time quantitative PCR and Western blot analysis. In vitro functional assays and in vivo xenograft models were used to analyse the function of LINC01116 in LUAD. Thus, the molecular correlation between miR-9-5p and CCNE1 was investigated through direct and indirect mechanism experiments. LINC01116, miR-9-5p and CCNE1 were upregulated in LUAD cell lines and tissues and were associated with a poor prognosis in patients. LINC01116 depletion inhibited proliferation but facilitated cell apoptosis. AGO2-RNA binding protein immunoprecipitation (AGO2-RIP) experiments confirmed that AGO2 binds to LINC01116 and miR-9-5p, indicating that LINC01116 interacts with miR-9-5p. The overexpression of miR-9-5p and CCNE1 effectively counteracts the biological effects of LINC01116 knockdown on reduced proliferation and cell cycle arrest in LUAD cells. The downregulation of miR-9-5p significantly reduces the CCNE1 level in A549 cells, and the upregulation of LINC01116 counteracts the downregulation of miR-9-5p effect, restoring the expression level of CCNE1. Our data demonstrated that LINC01116 regulates the expression of CCNE1 by positively regulating miR-9-5p, thereby affecting cell cycle, proliferation and participating in the development of LUAD.

Zhang H ，Cai W ，Miao Y ，Gu Y ，Zhou X ，Kaneda H ，Wang L ... -  《-》

Long noncoding RNA LINC01106 promotes lung adenocarcinoma progression via upregulation of autophagy.

Long noncoding RNA, LINC01106 exhibits high expression in lung adenocarcinoma (LUAD) tumor tissues, but its functional role and regulatory mechanism in LUAD cells remain unclear. LINC01106 expression was analyzed in LUAD tissues and its functional impact on LUAD cells was assessed. LUAD cells were silenced with sh-LINC01106 and injected into nude mice to investigate tumor growth. The downstream transcription factors and molecular mechanism were determined using the Human transcription factor database (TFDB) database and Gene Expression Profiling Interactive Analysis (GEPIA) database. Additionally, the impact of linc01106 on autophagy was analyzed by determining the expression of autophagy-related genes (ATGs) in LUAD cells. Our results showed that LINC01106 exhibited upregulation in both LUAD tissues and cell lines. The silencing of LINC01106 demonstrated a suppressive effect on tumorigenesis in a xenograft mouse model of LUAD. Additionally, LINC01106 was found to recruit TATA-binding protein-associated factor 15 (TAF15), an RNA-binding protein, thereby enhancing the mRNA stability of TEA domain transcription factor 4 (TEAD4). In turn, TEAD4 served as a transcription factor that bound to the LINC01106 promoter and regulated its expression. Further assays indicated that LINC01106 promoted autophagy in LUAD cells by upregulating the expression of autophagy-related genes (ATGs). The silencing of LINC01106 in LUAD cells inhibited autophagy, and cell proliferation, and promoted apoptosis, which all were effectively reversed by ATG5 overexpression. Overall, LINC01106, transcriptionally activated by TEAD4, interacts with TAF15 to promote the stability of TEAD4 and upregulates the expression of ATGs, promoting malignancy of LUAD cells.

Sun G ，Zheng Y ，Cai J ，Gao J ，Dong L ，Zhang X ，Huang Y ... -  《-》

Sinensetin Inhibits Angiogenesis in Lung Adenocarcinoma via the miR-374c-5p/VEGF-A/VEGFR-2/AKT Axis.

Sinensetin is a product isolated from Orthosiphon aristatus, and its antitumor activities have been well established. This study focused on the role and mechanism of sinensetin in lung adenocarcinoma (LUAD). LUAD cells were treated with various concentrations of sinensetin. The proliferation, migration, invasion, and angiogenesis of LUAD cells were detected using colony formation, transwell, and tube formation assays, respectively. The protein levels of VEGF-A, VEGFR-2, and phosphorylated AKT (ser473) were measured by western blotting. The targeted relationship between VEGF-A and miR-374c-5p was verified by luciferase reporter assay. BALB/c nude mice inoculated with A549 cells were treated with sinensetin (40 mg/kg/day) by gavage for 21 days to investigate the effect of sinensetin on tumor growth and angiogenesis in vivo. We found that sinensetin reduced proliferation, migration, invasion, angiogenesis, and cancer stem characteristics of LUAD cells. Sinensetin also suppressed LUAD tumor growth and angiogenesis in vivo. Sinensetin downregulated VEGF-A expression in LUAD cells by enhancing miR-374c-5p expression. MiR-374c-5p inhibited the VEGF-A/VEGFR-2/AKT pathway in LUAD cells. The antitumor effect of sinensetin was reversed by overexpression of VEGF-A or inhibition of miR-374c-5p. Overall, sinensetin upregulates miR-374c-5p to inhibit the VEGF-A/VEGFR-2/AKT pathway, thereby exerting antitumor effect on LUAD.

Ji T ，Ye L ，Xi E ，Liu Y ，Wang X ，Wang S ... -  《-》

RBIS regulates ribosome biogenesis to affect progression in lung adenocarcinoma.

Increased ribosome biogenesis is required for tumor growth. In this study, we investigated the function and underlying molecular mechanism of ribosome biogenesis factor (RBIS) in the progression of non-small cell lung cancer (NSCLC). In our study, we conducted a comprehensive analysis to identify key genes implicated in ribosome biogenesis by leveraging a Gene Set Enrichment Analysis (GSEA) dataset. Subsequently, we performed a comparative analysis of gene expression profiles by utilizing data from the Gene Expression Omnibus (GEO) datasets to ascertain differentially expressed genes (DEGs) between cancerous and adjacent non-cancerous tissues. Through the intersection of gene sets derived from GSEA and GEO, we identified a cohort of ribosome-associated genes that might exert a substantial influence on the progression of lung adenocarcinoma. Following an extensive literature review, we have identified the RBIS gene as an interesting candidate for further investigation. To elucidate the in vitro functional role of RBIS, several assays was employed, including the Transwell migration and invasion assay, wound healing assay, Cell Counting Kit-8 (CCK-8) proliferation assay, and colony formation assay. Subcutaneous and tail vein injection-based lung metastasis xenograft tumor models were used in evaluating the tumorigenic potential, growth, and metastatic spread of lung cancer cells. Flow cytometry analysis was employed to investigate cell cycle distribution and apoptotic rates. Additionally, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was utilized to quantify the mRNA expression levels of genes. To comprehensively assess the translational efficiency of nascent proteins, we employed polysome profiling analysis to provide insights into the cellular translational landscape. Furthermore, we quantified global protein synthesis using a fluorescence-based assay to measure protein synthesis rates. The immunofluorescence technology was utilized to study the subcellular reorganization of the nucleolus. We conducted co-immunoprecipitation (Co-IP) assays followed by Western blot analysis to identify potential proteins interacted with RBIS. The half maximal inhibitory concentration (IC50) was used for evaluating the chemosensitivity of lung cancer cells to gemcitabine. Additionally, the colony formation assay was employed to assess the survival and proliferative capacity post-treatment of gemcitabine. The database analysis showed that RBIS was upregulated in lung adenocarcinoma, and its high expression was associated with poor prognosis; Knockdown of RBIS significantly inhibited NSCLC cell migration, invasion and proliferation in vitro and xenograft tumor growth and metastasis in vivo. Additionally, knockdown of RBIS led to G0/G1 phase arrest and significantly increased apoptosis in lung adenocarcinoma cells. Mechanistically, downregulation of RBIS significantly decreased the expression of 47S ribosomal RNA (rRNA), a component associated with ribosome assembly. Polysome profiling analysis indicated that RBIS knockdown affected protein translation efficiency, and global protein synthesis assay further verified that RBIS knockdown inhibited synthesis of newborn proteins. Additionally, the ribosomal biogenesis-targeting drugs CX-5461 and the loss of RBIS exhibited synergistic effects in inhibiting cell cycle progression and inducing apoptosis. Furthermore, the ribosomal maturation factor GNL2 was identified as the key downstream regulator of RBIS in ribosome biogenesis. Notably, knockdown of RBIS substantially increased the sensitivity of lung adenocarcinoma cells to the chemotherapeutic drug gemcitabine, highlighting its l role in chemotherapy. Collectively, these studies suggested the close involvement of RBIS in the progression of lung adenocarcinoma, providing new insights for targeted therapeutic interventions involving ribosomes.

Pan H ，Liao L ，Xu S ，Xu Y ，Chai W ，Liu X ，Li J ，Cao Y ，Sun L ，Liu Q ，Yan M ... -  《Journal of Translational Medicine》