MicroRNA-486-5p Suppresses Lung Cancer via Downregulating mTOR Signaling In Vitro and In Vivo

Regulation and therapeutic potentials of microRNAs to non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 80%-85% of total cases and leading to millions of deaths worldwide. Drug resistance is the primary cause of treatment failure in NSCLC, which urges scientists to develop advanced approaches for NSCLC treatment. Among novel approaches, the miRNA-based method has emerged as a potential approach as it allows researchers to modulate target gene expression. Subsequently, cell behaviors are altered, which leads to the death and the depletion of cancer cells. It has been reported that miRNAs possess the capacity to regulate multiple genes that are involved in various signaling pathways, including the phosphoinositide 3-kinase, receptor tyrosine kinase/rat sarcoma virus/mitogen-activated protein kinase, wingless/integrated, retinoblastoma, p53, transforming growth factor β, and nuclear factor-kappa B pathways. Dysregulation of these signaling pathways in NSCLC results in abnormal cell proliferation, tissue invasion, and drug resistance while inhibiting apoptosis. Thus, understanding the roles of miRNAs in regulating these signaling pathways may enable the development of novel NSCLC treatment therapies. However, a comprehensive review of potential miRNAs in NSCLC treatment has been lacking. Therefore, this review aims to fill the gap by summarizing the up-to-date information on miRNAs regarding their targets, impact on cancer-associated pathways, and prospective outcomes in treating NSCLC. We also discuss current technologies for delivering miRNAs to the target cells, including virus-based, non-viral, and emerging extracellular vesicle-based delivery systems. This knowledge will support future studies to develop an innovative miRNA-based therapy and select a suitable carrier to treat NSCLC effectively.

The Molecular Pathogenesis of Tumor-Suppressive miR-486-5p and miR-486-3p Target Genes: GINS4 Facilitates Aggressiveness in Lung Adenocarcinoma

The involvement of passenger strands of miRNAs in the molecular pathogenesis of human cancers is a recent concept in miRNA research, and it will broaden our understanding of the molecular mechanisms of miRNA-mediated cancer. The analysis of our miRNA signature of LUAD revealed that both strands of pre-miR-486 (miR-486-5p and miR-486-3p) were downregulated in LUAD tissues. Ectopic expression of both miRNAs induced cell cycle arrest in LUAD cells, suggesting both strands of miRNAs derived from pre-miR-486 were tumor suppressive. Our in silico analysis showed a total of 99 genes may be under the control of both miRNAs in LUAD cells. Importantly, among these targets, the high expression of seven genes (MKI67, GINS4, RRM2, HELLS, MELK, TIMELESS, and SAPCD2) predicted a poorer prognosis of LUAD patients (p < 0.05). We focused on GINS4, a DNA replication complex GINS protein that plays an essential role in the initiation of DNA replication. Our functional assays showed that GINS4 was directly controlled by both strands of pre-miR-486, and its aberrant expression facilitated the aggressive behavior of LUAD cells. GINS4 is attractive as a therapeutic target for this disease. MiRNA analysis, including passenger strands, will further improve our understanding of the molecular pathogenesis of LUAD.

Diagnostic and prognostic value of microRNA-486 in patients with lung cancer: A systematic review and meta-analysis

PURPOSE

There are conflicting opinions on whether miR-486 could be used for cancer diagnosis and prognosis. Therefore, this present study investigated the potential effect of miR-486 on lung cancer diagnosis and prognosis.

METHODS

We researched PubMed, Embase, Wanfang and Chinese National Knowledge Infrastructure databases to select relevant publications. Specificity and sensitivity were obtained for the pooled and subgroup diagnostic meta-analysis while the hazard ratio was for prognostic meta-analysis. Publication analyses and sensitivity analyses were conducted to investigate possible sources of heterogeneity.

RESULTS

The overall sensitivity and specificity with 95% confidence intervals were 0.8 (0.8-0.9) and 0.9 (0.9-0.9). Results of subgroup analysis showed that high diagnostic efficacy might be obtained by miR-486 combined with other microRNAs (area under the curve (AUC): 0.9 (0.9-1.0)) to distinguish lung cancer patients from healthy controls (AUC: 1.0 (0.9-1.0)), especially for lung adenocarcinoma (AUC: 1.0 (1.0-1.0)) in the Asian population (AUC: 0.9 (0.9-1.0)). For prognosis prediction of miR-486 in overall non-small cell lung cancer, the overall hazard ratio with 95% confidence interval was 1.15 (0.85-1.54) for high versus low expression of miR-486, which indicated that a high miR-486 level was not related to the high risk of poor outcome. However, for the subgroup of progression-free survival and patients with chemotherapy, the hazard ratio was 0.41 (0.21-0.77), indicating that the higher miR-486 level would decrease the risk of poor progression-free survival for lung cancer patients with chemotherapy.

CONCLUSION

This study suggested circulating miR-486 combined with other microRNAs could be used as ideal biomarkers in early diagnosis and prognosis prediction for lung cancer, especially for lung adenocarcinoma in the Asian population.

Identification of the Key miRNAs and Genes Associated with the Regulation of Non-Small Cell Lung Cancer: A Network-Based Approach

Lung cancer is the major cause of cancer-associated deaths across the world in both men and women. Lung cancer consists of two major clinicopathological categories, i.e., small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Lack of diagnosis of NSCLC at an early stage in addition to poor prognosis results in ineffective treatment, thus, biomarkers for appropriate diagnosis and exact prognosis of NSCLC need urgent attention. The proposed study aimed to reveal essential microRNAs (miRNAs) involved in the carcinogenesis of NSCLC that probably could act as potential biomarkers. The NSCLC-associated expression datasets revealed 12 differentially expressed miRNAs (DEMs). MiRNA-mRNA network identified key miRNAs and their associated genes, for which functional enrichment analysis was applied. Further, survival and validation analysis for key genes was performed and consequently transcription factors (TFs) were predicted. We obtained twelve miRNAs as common DEMs after assessment of all datasets. Further, four key miRNAs and nine key genes were extracted from significant modules based on the centrality approach. The key genes and miRNAs reported in our study might provide some information for potential biomarkers profitable to increased prognosis and diagnosis of lung cancer.

Prognostic Significance of HMGA1 Expression in Lung Cancer Based on Bioinformatics Analysis

High-mobility group protein 1 (HMGA1) participates in the processes of DNA transcription, replication, recombination, and repair. The HMGA1 gene is expressed abundantly during embryogenesis and is reactivated during carcinogenesis. HMGA1 gene expression has been associated with a high degree of malignancy, metastatic tendency, and poor survival in breast, colon, ovary, and pancreatic cancers. However, its prognostic significance in lung cancer remains unclear. Using publicly available data, HMGA1 was shown to be overexpressed in both small and non-small lung tumors, with higher expression compared to both the adjacent non-malignant lung tissues and non-tumor lung tissues of healthy individuals. Elevated HMGA1 expression could result from lowered HMGA1 methylation and was connected with some clinicopathological features like sex, age, and stage of the disease. The high HMGA1 expression level was connected with shorter overall and first progression survival time among lung adenocarcinoma patients, but not lung squamous cell carcinoma patients. HMGA1 could interact with proteins involved in cellular senescence and cell cycle control (TP53, RB1, RPS6KB1, and CDK1), transcription regulation (EP400 and HMGA2), chromatin assembly and remodeling (LMNB1), and cholesterol and isoprene biosynthesis (HMGCR and INSIG1). Taken together, HMGA1 overexpression could be an essential element of lung carcinogenesis and a prognostic feature in lung cancer.

MicroRNA-21 was a promising biomarker for lung carcinoma diagnosis: An update meta-analysis

Objective

To investigate the diagnostic performance of microRNA‐21 detected in serum or sputum as a biomarker for lung carcinoma identification through pooling the open published data.

Methods

Clinical diagnostic studies related to microRNA‐21 as a biomarker for lung carcinoma identification were electronically searched in the databases of Pubmed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, and Google Scholar. The data of the included studies was extracted and made pooling of diagnostic sensitivity, specificity, diagnostic odds ratio (DOR), area under the summary receiver operating characteristic curve (ROC) (AUC) for microRNA‐21 expression in serum or sputum as a biomarker for lung carcinoma identification. The publication bias was evaluated by Deek's funnel plot.

Results

Seventeen diagnostic studies were finally included and made data pooling. For the included 17 studies, 4 investigated the microRNA‐21 expression in sputum and 13 studies in serum. The pooled diagnostic sensitivity and specificity were 0.73 (95% CI, 0.67–0.78) and 0.81 (95% CI, 0.75–0.85), respectively, under random effect model. The combined DOR was 9.65 (95% CI, 6.64–14.03) with the AUC of 0.84 (95% CI, 0.80–0.87). Given a pre‐test probability of 50%, the post‐test positive probability and post‐test negative probability were 79% and 25%, respectively, by using microRNA‐21 as a biomarker for lung carcinoma diagnosis. Deek's funnel was obviously asymmetry and indicated significant publication bias (p < 0.05).

Conclusion

MicroRNA‐21 in serum or sputum was a promising biomarker for lung cancer identification with relative high diagnostic sensitivity and specificity.