Long noncoding RNA SBF2-AS1 contributes to the growth and metastatic phenotypes of NSCLC via regulating miR-338-3p/ADAM17 axis

Long non‑coding RNAs as potential therapeutic targets in non‑small cell lung cancer (Review)

Non‑small cell lung cancer (NSCLC) is one of the most common malignancies with a high morbidity and mortality rate. Long non‑coding RNAs (lncRNAs) have been reported to be closely associated with the occurrence and progression of NSCLC. In addition, lncRNAs have been documented to participate in the development of drug resistance and radiation sensitivity in patients with NSCLC. Due to their extensive functional characterization, high tissue specificity and sex specificity, lncRNAs have been proposed to be novel biomarkers and therapeutic targets for NSCLC. Therefore, in the current review, the functional classification of lncRNAs were presented, whilst the potential roles of lncRNAs in NSCLC were also summarized. Various physiological aspects, including proliferation, invasion and drug resistance, were all discussed. It is anticipated that the present review will provide a perspective on lncRNAs as potential diagnostic molecular biomarkers and therapeutic targets for NSCLC.

YBX1/lncRNA SBF2-AS1 interaction regulates proliferation and tamoxifen sensitivity via PI3K/AKT/MTOR signaling in breast cancer cells

BACKGROUND

Y-box binding protein 1 (YBX1) is a multifunctional oncoprotein that can interact with several long non-coding RNAs (lncRNAs) to regulate metastasis in malignancies including breast cancer (BC). In the present study, we demonstrated the association of YBX1 with oncogenic lncRNA SBF2-AS1 (SET-binding factor 2 antisense RNA 1) via PI3K/AKT/mTOR signaling to regulate BC cell proliferation. We further explored the involvement of the YBX1/SBF2-AS1/PI3K/AKT/mTOR axis in the restoration of tamoxifen (TAM) sensitivity.

METHODS AND RESULTS

YBX1-SBF2-AS1 association was predicted in silico and verified by RNA immunoprecipitation (RIP)-qPCR assay. Transfection experiments, Real-time RT PCR, Western blots, Phospho AKT/mTOR antibody array kit, and cell proliferation/apoptosis assays were employed to detect the YBX1/SBF2-AS1/ PI3K/AKT/mTOR axis and its effects upon TAM treatment in vitro. We identified that the YBX1 protein specifically binds to lncRNA SBF2-AS1. Our transfection experiments in MCF-7 and MDA-MB-468 cells with SBF2-AS1 silenced or overexpressed YBX1 plasmids, and their negative controls revealed that YBX1 regulates the expression of SBF2-AS1 by forming a positive feedback loop for its activation. We further demonstrated YBX1-SBF2-AS1 association exerts its effects on cell proliferation via PI3K/AKT/mTOR signaling pathway. Furthermore, we observed an increase in TAM sensitivity in BC cells after the knockdown of YBX1-SBF2-AS1 marked by decreased cell proliferation through disruption of the PI3K/AKT/mTOR axis.

CONCLUSION

Our study has identified a novel YBX1/SBF2-AS1/PI3K/AKT/mTOR regulatory axis which may serve as a potential target to improve the effectiveness and efficacy of TAM treatment in BC.

Upregulation of XIAP promotes lung adenocarcinoma brain metastasis by modulating ceRNA network

Dysregulation of XIAP has been shown to affect the progression of a variety of cancers, including lung adenocarcinoma (LUAD). However, the function and mechanisms of XIAP in lung adenocarcinoma with brain metastasis (LUAD-BM) remains poorly understood. In this study, we analyzed the differential mRNA of 58 lung adenocarcinomas samples and 28 lung adenocarcinomas with brain metastases in GEO database. 191 differentially expressed mRNAs were significantly associated with immune response, the proliferation of the immune cell, cell-cell adhesion. Subsequent analyzed by lasso and SVM found that XIAP was significantly elevated in LUAD-BM and significantly associated with LUAD grade and metastasis. Then we constructed a molecular regulatory network of ncRNA-miRNA-mRNA ceRNA by Cystoscope based on the correlation obtained from Starbase. It was found that SBF2-AS1 or RUNDC3A-AS1, has-miR-338-3p and XIAP may have a regulatory relationship. Furthermore, we also initially found that XIAP was closely correlation with T cells, B cells, Mast cells, macrophages, and dendritic cells. In conclusion, we found that XIAP was significantly higher expressed in LUAD-BM compared with LUAD without brain metastasis, suggesting that XIAP may play an important role in the future prediction and clinical treatment of LUAD-BM.

LncRNA SBF2-AS1: A Budding Star in Various Cancers

Long non-coding RNA (lncRNA) is a new kind of RNA with lengths over 200 nucleotides. Current frontiers revealed that lncRNAs implicate in various tumor progression, including tumorigenesis, proliferation, migration, invasion, metastasis and angiogenesis. Recently discovered long non-coding RNA SET-binding factor 2 antisense RNA 1 (lncRNA SBF2-AS1), an oncogenic antisense RNA to SBF2, locates at 11p15.1 locus and is 2708 nt long. Accumulating evidences have demonstrated that lncRNA SBF2-AS1 participates in various tumor progression including pathogenesis, diagnosis, treatment and prognosis of acute myeloid leukemia (AML), breast cancer (BC), cervical cancer (CC), clear cell renal cell carcinoma (ccRCC), colorectal cancer (CRC), diffuse large B-cell lymphoma (DLBCL), esophageal squamous cell carcinoma (ESCC), gastric cancer (GC), glioma, glioblastoma (GBM), hepatocellular carcinoma (HCC), lung cancer (LC), lung adenocarcinoma (LUAD), non-small cell lung cancer (NSCLC), osteosarcoma (OS), pancreatic cancer (PC), papillary thyroid cancer (PTC), small cell lung cancer (SCLC). Therefore, we summarized the underlying mechanisms about lncRNA SBF2-AS1 in various cancers to utilize its therapeutic function in target-selective treatment modality.

Circular RNA circ_0010235 sponges miR-338-3p to play oncogenic role in proliferation, migration and invasion of non-small-cell lung cancer cells through modulating KIF2A

BACKGROUND

Circular RNA microarray analysis showed hsa_circ_0010235 (circ_0010235) was highly upregulated in non-small-cell lung cancer (NSCLC) patients; however, its role in carcinogenesis and development of NSCLC cells was unrevealed. Here, we intended to investigate role and mechanism of circ_0010235 in NSCLC proliferation, migration and invasion.

METHODS AND RESULTS

Expression of circ_0010235, microRNA (miR)-338-3p and kinesin family member 2A (KIF2A) was detected by quantitative real-time PCR, western blotting and immunohistochemistry (IHC). Cell progression was measured by cell-counting kit-8 assay, 5-ethynyl-2-deoxyuridine (EdU) assay, flow cytometry, transwell assay, western blotting, IHC and xenograft experiment. The relationship among circ_0010235, miR-338-3p and KIF2A was determined by dual-luciferase reporter assay, RNA immunoprecipitation and Pearson's correlation analysis. Expression of circ_0010235 was increased in human NSCLC tissues and cells, accompanied with miR-338-3p downregulation and KIF2A upregulation. Essentially, circ_0010235 could sponge miR-338-3p via target binding, and miR-338-3p downstream targeted KIF2A. Functionally, exhaustion of circ_0010235 induced apoptosis rate of NSCLC cells and curbed cell viability, EdU incorporation, migration rate and invasion rate, accompanied with higher E-cadherin and lower N-cadherin expression. Additionally, re-expression of miR-338-3p prompted above similar effects in NSCLC cells in vitro. Contrarily, miR-338-3p blockage partially counteract the effects of circ_0010235 exhaustion; plus, restoration of KIF2A could attenuate miR-338-3p role, as well. Notably, interfering circ_0010235 delayed tumour growth of NSCLC cells by promoting miR-338-3p and E-cadherin expression, and depressing KIF2A, ki-67 and N-cadherin expression.

CONCLUSIONS

circ_0010235 could be a novel identified oncogenic circRNA in NSCLC, and targeting miR-338-3p/KIF2A axis was one regulatory mechanism underlying circ_0010235.KEY MESSAGECirc_0010235 was an upregulated circRNA in NSCLC patients and cells.Interfering circ_0010235 restrained NSCLC cell proliferation and metastasis in vitro and in vivo.miR-338-3p per se suppressed NSCLC in vitro and its downregulation diminished the tumour-suppressive role of circ_0010235 blockage in NSCLC cells.miR-338-3p could downstream target KIF2A and be sponged by circ_0010235.

Exosomal miR-338-3p suppresses non-small-cell lung cancer cells metastasis by inhibiting CHL1 through the MAPK signaling pathway

Globally, lung cancer remains one of the most prevalent malignant cancers. However, molecular mechanisms and functions involved in its pathogenesis have not been clearly elucidated. This study aimed to evaluate the specific regulatory mechanisms of exosomal miR-338-3p/CHL1/MAPK signaling pathway axis in non-small-cell lung cancer. Western blotting and qRT-PCR (reverse transcription-polymerase chain reaction) were used to determine the expression levels of CHL1 and exosomal miR-338-3p in NSCLC (non-small-cell lung cancer). The CHL1 gene was upregulated and downregulated to evaluate its functions in NSCLC progression. In vitro MTS and apoptotic assays were used to investigate the functions of CHL1 and exosomal miR-338-3p in NSCLC progression. The high-throughput sequencing was used to explore differently expressed exosomal miRNAs. The biological relationships between MAPK signaling pathway and CHL1 and exosomal miR-338-3p in NSCLC were predicted through bioinformatics analyses and verified by western blotting. Elevated CHL1 levels were observed in NSCLC tissues and cells. Upregulated CHL1 expression enhanced NSCLC cells’ progression by promoting tumor cells proliferation while suppressing their apoptosis. Conversely, the downregulation of the CHL1 gene inhibited NSCLC cells’ growth and promoted tumor cells’ apoptotic rate. Additionally, CHL1 activated the MAPK signaling pathway. Besides, we confirmed that miR-338-3p directly sponged with CHL1 to mediate tumor cells progression. Moreover, exosomal miR-338-3p serum levels in NSCLC patients were found to be low. BEAS-2B cells can transfer exosomal miR-338-3p to A549 cells and SK-MES-1 cells. In addition, elevated exosomal miR-338-3p levels significantly inhibited tumor cells proliferation and promoted their apoptosis by suppressing activation of the MAPK signaling pathway. Exosomal miR-338-3p suppresses tumor cells' metastasis by downregulating the expression of CHL1 through MAPK signaling pathway inactivation.

Emerging roles of a pivotal lncRNA SBF2-AS1 in cancers

Long non-coding RNAs refer to transcripts over 200 nt in length that lack the ability to encode proteins, which occupy the majority of the genome and play a crucial role in the occurrence and development of human diseases, especially cancers. SBF2-AS1, a newly identified long non-coding RNA, has been verified to be highly expressed in diversiform cancers, and is involved in processes promoting tumorigenesis, tumor progression and tumor metastasis. Moreover, upregulation of SBF2-AS1 expression was significantly related to disadvantageous clinicopathologic characteristics and indicated poor prognosis. In this review, we comprehensively summarize the up-to-date knowledge of the detailed mechanisms and underlying functions of SBF2-AS1 in diverse cancer types, highlighting the potential of SBF2-AS1 as a diagnostic and prognostic biomarker and even a therapeutic target.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

The Clinical Prognostic Value of lncRNA SBF2-AS1 in Cancer Patients: A Meta-Analysis

Background:

The mortality and recurrence of patients with cancer is of high prevalence. SET-binding factor 2 (SBF2) antisense RNA1 (lncRNA-SBF2-AS1) is a promising long non-coding RNA. There is increasing evidence that SBF2-AS1 is abnormally expressed in various tumors and is associated with cancer prognosis. However, the identification of the effect of lncRNA SBF2-AS1 in tumors remains necessary.

Materials and Methods:

Up to November 2, 2020, electronic databases, including PubMed, Cochrane Library, EMBASE, Medline, and Web of Science, were searched. The results were evaluated by pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs).

Results:

A total of 11 literatures on cancer patients were included for the present meta-analysis. The combined results revealed that high expression of SBF2-AS1 was significantly associated with unfavorable overall survival (OS) (HR = 1.48, 95% CI: 1.34-1.62, P < 0.00001) in a variety of cancers. In additional, the increase in SBF2-AS1 expression was also correlated with tumor size ((larger vs. smaller) OR = 2.34, 95% CI: 1.47-3.70, P = 0.0003), advanced TNM stage ((III/IV vs. I/II) OR = 2.78, 95% CI: 1.75-4.41, P < 0.0001), lymph node metastasis ((Positive vs. Negative) OR = 3.06, 95% CI: 1.93-4.86, P < 0.00001), and histological grade ((poorly vs. well/moderately) OR = 2.58, 95% CI: 1.47-4.52, P = 0.001) in patients with cancer. Furthermore, The Cancer Genome Atlas (TCGA) dataset valuated that SBF2-AS1 was upregulated in a variety of tumors, and predicted the worse prognosis.

Conclusions:

Our results of this meta-analysis demonstrate that high SBF2-AS1 expression may become a potential target for predicting the prognosis of human cancers.

Molecular interactions of miR-338 during tumor progression and metastasis

Background

Cancer, as one of the main causes of human deaths, is currently a significant global health challenge. Since the majority of cancer-related deaths are associated with late diagnosis, it is necessary to develop minimally invasive early detection markers to manage and reduce mortality rates. MicroRNAs (miRNAs), as highly conserved non-coding RNAs, target the specific mRNAs which are involved in regulation of various fundamental cellular processes such as cell proliferation, death, and signaling pathways. MiRNAs can also be regulated by long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). They are highly stable in body fluids and have tumor-specific expression profiles, which suggest their suitability as efficient non-invasive diagnostic and prognostic tumor markers. Aberrant expression of miR-338 has been widely reported in different cancers. It regulates cell proliferation, migration, angiogenesis, and apoptosis in tumor cells.

Main body

In the present review, we have summarized all miR-338 interactions with other non-coding RNAs (ncRNAs) and associated signaling pathways to clarify the role of miR-338 during tumor progression.

Conclusions

It was concluded that miR-338 mainly functions as a tumor suppressor in different cancers. There were also significant associations between miR-338 and other ncRNAs in tumor cells. Moreover, miR-338 has a pivotal role during tumor progression using the regulation of WNT, MAPK, and PI3K/AKT signaling pathways. This review highlights miR-338 as a pivotal ncRNA in biology of tumor cells.

Roles of the microRNA‑338‑3p/NOVA1 axis in retinoblastoma

Retinoblastoma (RB) is an intraocular malignancy that mainly affects young children. Previous reports have demonstrated that mutations or the inactivation of the RB1 gene were the main cause of RB; however, disruption of the intracellular signaling pathways following deficiency of RB1 requires further investigation. Based on the Gene Expression Omnibus data and bioinformatics prediction, the present study aimed to investigate the microRNA (miR)-338-3p/neuro-oncological ventral antigen 1 (NOVA1) axis in RB. Subsequently, overexpression and knockdown of miR-338-3p and NOVA1, respectively, were performed to study the role of miR-338-3p/NOVA1 in the progression of the RB cells. The results demonstrated that overexpression of miR-338-3p significantly inhibited cell proliferation, migration and invasion, and promoted apoptosis of the RB cells. Moreover, knockdown of NOVA1 showed similar results. A dual-luciferase reporter assay and rescue experiments further confirmed the direct binding between miR-338-3p and NOVA1. Taken together, the results indicated that miR-338-3p acted as tumor suppressor by targeting the oncogene of NOVA1 in RB, which may serve as potential therapeutic targets in RB.

The role of microRNA-338-3p in cancer: growth, invasion, chemoresistance, and mediators

Cancer still remains as one of the leading causes of death worldwide. Metastasis and proliferation are abnormally increased in cancer cells that subsequently, mediate resistance of cancer cells to different therapies such as radio-, chemo- and immune-therapy. MicroRNAs (miRNAs) are endogenous short non-coding RNAs that can regulate expression of target genes at post-transcriptional level and capable of interaction with mRNA-coding genes. Vital biological mechanisms including apoptosis, migration and differentiation are modulated by these small molecules. MiRNAs are key players in regulating cancer proliferation and metastasis as well as cancer therapy response. MiRNAs can function as both tumor-suppressing and tumor-promoting factors. In the present review, regulatory impact of miRNA-338-3p on cancer growth and migration is discussed. This new emerging miRNA can regulate response of cancer cells to chemotherapy and radiotherapy. It seems that miRNA-338-3p has dual role in cancer chemotherapy, acting as tumor-promoting or tumor-suppressor factor. Experiments reveal anti-tumor activity of miRNA-338-3p in cancer. Hence, increasing miRNA-338-3p expression is of importance in effective cancer therapy. Long non-coding RNAs, circular RNAs and hypoxia are potential upstream mediators of miRNA-338-3p in cancer. Anti-tumor agents including baicalin and arbutin can promote expression of miRNA-338-3p in suppressing cancer progression. These topics are discussed to shed some light on function of miRNA-338-3p in cancer cells.