ELK1-induced upregulation of lncRNA HOXA10-AS promotes lung adenocarcinoma progression by increasing Wnt/β-catenin signaling

HOXA10-AS Enhances Gastric Cancer Cell Proliferation, Migration, and Invasion via the p38 MAPK/STAT3 Signaling Pathway

Gastric cancer (GC) represents a major global health concern, with over 1 million new cases diagnosed annually worldwide. Emerging studies have highlighted the significant correlation between long noncoding RNAs (lncRNAs) and the progression of GC. The objective of the current study is to investigate the roles and mechanism of lncRNA homeobox A10 antisense RNA (HOXA10-AS) in modulating malignant properties of GC cells. RT-qPCR was employed to detect HOXA10-AS expression in GC cells or human normal gastric epithelium cells. The cellular localization of HOXA10-AS and mRNA HOXA10 were detected using RNA fractionation assays. Colony forming assays and Transwell assays were performed to assess the proliferative, invasive, and migratory capabilities of GC cells. Western blot analysis was used to determine protein levels of epithelial mesenchymal transition (EMT) markers in GC cells. RNA immunoprecipitation, RNA pulldown assays and luciferase assays were conducted to explore gene interaction. As shown by experimental results, HOXA10-AS showed high expression in GC cells. The silencing of HOXA10-AS led to weakened proliferative, invasive, and migratory abilities of GC cells, as well as inhibition of the EMT process. Moreover, HOXA10-AS positively regulated HOXA10 expression by interacting with miR-29a/b/c-3p. Additionally, overexpression of HOXA10 counteracted the repressive impacts on malignant cellular process caused by the knockdown of HOXA10-AS. Furthermore, HOXA10-AS activated the p38 MAPK/STAT3 signaling pathway via upregulation of HOXA10. In conclusion, HOXA10-AS upregulates HOXA10 expression through interaction with miR-29a/b/c-3p. The resultant increase in HOXA10 expression activates the p38 MAPK/STAT3 signaling, thereby promoting GC cell growth, migration, invasion, and EMT process.

LncRNA HOXA10-AS as a novel biomarker and therapeutic target in human cancers

Long non-coding RNAs (lncRNAs) are crucial regulatory molecules that participate in numerous cellular development processes, and they have gathered much interest recently. HOXA10 antisense RNA (HOXA10-AS, also known as HOXA-AS4) is a novel lncRNA that was identified to be dysregulated in some prevalent malignancies. In this review, the clinical significance of HOXA10-AS for the prognosis of various cancers is analyzed. In addition, the major advances in our understanding of the cellular biological functions and mechanisms of HOXA10-AS in different human cancers are summarized. These cancers include esophageal carcinoma (ESCA), gastric cancer (GC), glioma, laryngeal squamous cell carcinoma (LSCC), acute myeloid leukemia (AML), lung adenocarcinoma (LUAD), nasopharyngeal carcinoma (NPC), oral squamous cell carcinoma (OSCC), and pancreatic cancer. We also note that the aberrant expression of HOXA10-AS promotes malignant progression through various underlying mechanisms. In conclusion, HOXA10-AS is expected to serve as an ideal clinical biomarker and an effective cancer therapy target.

Long non-coding RNAs as the pivotal regulators of epithelial mesenchymal transition through WNT/β-catenin signaling pathway in tumor cells

Tumor cell invasion is considered as one of the main therapeutic challenges in cancer patients, which leads to distant metastasis and reduced prognosis. Therefore, investigation of the factors involved in tumor cell invasion improves the therapeutic methods to reduce tumor metastasis. Epithelial-mesenchymal transition (EMT) process has a pivotal role in tumor cell invasion and metastasis, during which tumor cells gain the invasive ability by losing epithelial characteristics and acquiring mesenchymal characteristics. WNT/β-catenin signaling pathway has a key role in tumor cell invasion by regulation of EMT process. Long non-coding RNAs (lncRNAs) have also an important role in EMT process through the regulation of WNT/β-catenin pathway. Deregulation of lncRNAs is associated with tumor metastasis in different tumor types. Therefore, in the present review, we investigated the role of lncRNAs in EMT process and tumor cell invasion through the regulation of WNT/β-catenin pathway. It has been reported that lncRNAs mainly induced the EMT process and tumor cell invasion through the activation of WNT/β-catenin pathway. LncRNAs that regulate the WNT/β-catenin mediated EMT process can be introduced as the prognostic markers as well as suitable therapeutic targets to reduce the tumor metastasis in cancer patients.

LncRNA SNHG4 Modulates EMT Signal and Antitumor Effects in Endometrial Cancer through Transcription Factor SP-1

Long non-coding RNAs (lncRNAs) are implicated in the initiation and progression of a variety of tumors, including endometrial cancer. However, the mechanisms of lncRNA in endometrial cancer formation and progression remain largely unknown. In this study, we confirmed that the lncRNA SNHG4 is upregulated in endometrial cancer and correlates with lower survival rates in endometrial cancer patients. Knock-down of SNHG4 significantly reduced cell proliferation, colonization, migration, and invasion in vitro, as well as modulating the cell cycle and reduced tumor growth of endometrial cancer in vivo. In addition, the effect of SNHG4 by the transcription factor SP-1 was confirmed in vitro. We found in this study that SNHG4/SP-1 plays an important role in endometrial cancer progression and may be used as a potential therapeutic and prognostic biomarker for endometrial cancer.

LncRNA HOXA10-AS promotes the progression of esophageal carcinoma by regulating the expression of HOXA10

Esophageal cancer (EC) remains a primary cause of cancer-associated fatality worldwide and is characterized by poor prognosis. HOXA10-AS is reported to be relevant with the development of different human cancers. However, its role and regulatory mechanism in EC are still obscure. Our study targeted at investigating the functional and mechanical roles of HOXA10-AS in EC. We confirmed by RT-qPCR that HOXA10-AS presented a remarkably high expression in EC cells. Functional experiments demonstrated that knocking down HOXA10-AS weakened proliferation, invasion and migration in vitro and impeded tumorigenesis in vivo. Further, we found that HOXA10-AS positively regulated its neighbor gene HOXA10 and influenced EC cell biological activities depending on HOXA10. Mechanistically, we showed that HOXA10-AS combined with FMR1 to target and stabilize HOXA10 mRNA. Moreover, HOXA10 served as a transcriptional factor to stimulate the transcription of its target gene CHDH. Finally, rescue assays confirmed that HOXA10 influenced EC cell growth through modulating CHDH. In conclusion, our study first determines the function of HOXA10-AS in EC and demonstrates its mechanism relating to HOXA10/CHDH, suggesting HOXA10-AS as a potential novel target for EC treatment. [Figure: see text].

Circ-GSK3B up-regulates GSK3B to suppress the progression of lung adenocarcinoma

GSK3B is the mRNA form of glycogen synthase kinase 3 beta (GSK-3β), which is a critical repressor of Wnt/β-catenin signaling pathway and generally inhibited in cancer cells. Plenty of researches have disclosed that circular RNAs, namely circRNAs exert important functions in the progression of various human malignancies including lung adenocarcinoma (LUAD). Therefore, we attempted to explore whether there existed certain circRNAs that could mediate LUAD development by regulating GSK3B expression and Wnt/β-catenin pathway. In the present research, circ-GSK3B (hsa_circ_0066903) was found to be significantly down-regulated in LUAD tissues and cells and it suppressed the proliferation, migration and stemness of LUAD cells. Furthermore, it was discovered that circ-GSK3B competitively sponged miR-3681-3p and miR-3909 to elevate GSK3B expression. Circ-GSK3B could impair the binding ability of FKBP51 to GSK-3β to inhibit the phosphorylation of GSK-3β^S9, resulting in the inactivation of Wnt/β-catenin signaling. In addition, the regulatory effect of circ-GSK3B on LUAD tumorigenesis and cell progression was testified through in vitro and in vivo rescue experiments. In conclusion, circ-GSK3B suppressed LUAD development through up-regulating and activating GSK3B.

GPX4 suppresses ferroptosis to promote malignant progression of endometrial carcinoma via transcriptional activation by ELK1

Background

Glutathione Peroxidase 4 (GPX4) is a key protein that inhibits ferroptosis. However, its biological regulation and mechanism in endometrial cancer (EC) have not been reported in detail.

Methods

The expression of GPX4 in EC tissues was determined by TCGA databases, qRT-PCR, Western blot, and immunohistochemistry (IHC). The effects of GPX4 on EC cell proliferation, migration, apoptosis, and tumorigenesis were studied in vivo and in vitro. In addition, ETS Transcription Factor ELK1 (ELK1) was identified by bioinformatics methods, dual-luciferase reporter assay, and chromatin immunoprecipitation (ChIP). Pearson correlation analysis was used to evaluate the association between ELK1 and GPX4 expression.

Results

The expression of GPX4 was significantly up-regulated in EC tissues and cell lines. Silencing GPX4 significantly inhibited the proliferation, migration ability, induced apoptosis, and arrested the cell cycle of Ishikawa and KLE cells. Knockdown of GPX4 accumulated intracellular ferrous iron and ROS, disrupted MMP, and increased MDA levels. The xenograft tumor model also showed that GPX4 knockdown markedly reduced tumor growth in mice. Mechanically, ELK1 could bind to the promoter of GPX4 to promote its transcription. In addition, the expression of ELK1 in EC was positively correlated with GPX4. Rescue experiments confirmed that GPX4 knockdown could reverse the strengthens of cell proliferation and migration ability and the lower level of Fe²⁺ and MDA caused by upregulating ELK1.

Conclusion

The results of the present study suggest that ELK1 / GPX4 axis plays an important role in the progress of EC by promoting the malignant biological behavior and inducing ferroptosis of EC cells, which provides evidence for investigating the potential therapeutic strategies of endometrial cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09986-3.

+HOXA10-AS Promotes Malignant Phenotypes of Gastric Cancer via Upregulating HOXA10

Objective

To study the role of long noncoding RNA HOXA10-AS in gastric cancer (GC) and its underlying mechanism which is one of the most common and fetal malignancies. Long noncoding RNA HOXA10-AS is highly expressed and acts in an oncogenic role in cancers. However, its roles in GC are still unknown.

Methods

The expression of HOXA10-AS and HOXA10 in GC tissues from the TCGA database was analyzed. Western blot and qRT-PCR assays were applied to examine the expression of HOXA10-AS and HOXA10. Cell proliferation was evaluated with CCK-8 and EdU incorporation assays. Cell apoptosis was analyzed by flow cytometry. Migratory and invasive capacities were evaluated with wound healing and transwell assays.

Results

HOXA10-AS and HOXA10 were upregulated in GC, and their expressions were positively correlated. Knockdown of HOXA10-AS inhibited HOXA10 expression in GC cells. Furthermore, knockdown of HOXA10-AS restrained GC cell proliferation, migration, and invasion but promoted apoptosis. In addition, overexpression of HOXA10-AS promoted malignant phenotypes of GC cells, but all these effects could be reversed by knockdown of HOXA10.

Conclusion

HOXA10-AS promoted GC cell proliferation, migration and invasion and enhanced apoptosis via upregulating HOXA10. Our study implies a novel regulatory mechanism of malignant phenotypes and provides potential therapeutic targets for GC.

LncRNA HOXA10-AS Activated by E2F1 Facilitates Proliferation and Migration of Nasopharyngeal Carcinoma Cells Through Sponging miR-582-3p to Upregulate RAB31

Nasopharyngeal carcinoma (NPC) is a kind of head and neck cancer with a characteristic regional distribution. Increasing evidence has illustrated that long noncoding RNAs (lncRNAs) exert the regulatory function in tumor development. Nevertheless, the specific functions of lncRNA HOXA10 antisense RNA (HOXA10-AS) in NPC remain to be clarified. In this research, quantitative reverse transcription polymerase chain reaction detected HOXA10-AS expression in NPC cells. Cell counting kit-8, colony formation, and transwell assays were utilized to measure the proliferation and migration of NPC cells. Moreover, mechanism assays detected the interaction of different genes. Briefly, HOXA10-AS was highly expressed in NPC cells. HOXA10-AS down-regulation restrained NPC cell proliferation and migration. Further, HOXA10-AS could bind to miR-582-3p by acting as a competing endogenous RNA. Besides, Ras-related protein Rab-31 (RAB31) was proven as the target gene of miR-582-3p. Additionally, E2F transcription factor 1 (E2F1) acted as a transcription factor to activate HOXA10-AS expression. In the final rescue assays, we observed that the effect of HOXA10-AS depletion on NPC cell growth could be fully reversed by RAB31 overexpression or miR-582-3p inhibition. In short, our research proved that HOXA10-AS activated by E2F1 facilitated proliferation and migration of NPC cells through sponging miR-582-3p to upregulate RAB31.

Functions of lncRNA DUXAP8 in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) poses a serious threat to public health due to its significant morbidity and mortality rates. The processes of NSCLC formation and development are quite complex and involve numerous regulatory biomolecules. Long non-coding RNAs (lncRNAs) have attracted attention since they have been found to play critical roles in the tumorigenesis of various human malignancies. Recently, double homeobox A pseudogene 8 (DUXAP8) was identified as an oncogenic lncRNA that is overexpressed in different tumor types. In NSCLC, high expression of DUXAP8 is associated with poor prognosis in patients. The regulatory mechanism underlying the oncogenic effects of DUXAP8 can be divided into transcriptional level and post-transcriptional level. DUXAP8 promotes proliferation, epithelial-mesenchymal transition, and aerobic glycolysis in NSCLC cells. Moreover, DUXAP8 shows potential for the diagnosis and treatment of NSCLC. Herein, we review the molecular mechanisms underlying the DUXAP8-mediated phenotypes of NSCLC as well as its potential clinical applications.

A Pan-Cancer Landscape of HOX-Related lncRNAs and Their Association With Prognosis and Tumor Microenvironment

The highly conserved homology cassette family (HOX) as well as 18 referenced long non-coding antisense transcripts (HOXATs) play vital roles in the development of some cancers. Nevertheless, their expression patterns as well as their association with cancer prognosis and the tumor microenvironment (TME) in pan-cancers are still unclear. Here, based on public databases, the expression levels of HOXATs, their prognostic potentials, and correlation with tumor mutation burden (TMB), immune cell infiltration, immune subtype, immune response-related genes, and stemness scores corresponding to 33 tumor types were analyzed systematically using R language. The results of the analysis indicated that different cancer tissues show different HOXAT expression profiles. Further, HOXAT expression showed association with cancer prognosis and immune and stemness regulation. Gene set enrichment analysis also demonstrated that HOXATs participate in cancer- and immune-related pathways, and based on their expression levels, HOTAIRM1 and HOXB-AS1 showed potential involvement in oncogenesis as well as possible involvement in immune regulation across a variety of cancer types. Further investigation also confirmed a significantly higher expression of HOXB-AS1 in GBM than in lower grade glioma tissues. Importantly, in vitro cell function experiments indicated that HOXB-AS1 supports cancer stem cell and plays a fundamental role in glioma metastasis. In conclusion, our results provide valuable resources that can guide the investigation of the mechanisms related to the role of HOXATs in cancers as well as therapeutic analysis in this regard.

STAT1-Induced Upregulation lncRNA LINC00958 Accelerates the Epithelial Ovarian Cancer Tumorigenesis by Regulating Wnt/β-Catenin Signaling

Background

Growing studies have demonstrated that long noncoding RNAs (lncRNAs) play important roles in tumor progression. In this study, we aimed to explore the potential roles of lncRNA LINC00958 (LINC00958) and its biological functions in epithelial ovarian cancer (EOC).

Methods

The expression of LINC00958 in 11 cases of EOC and adjacent nontumor specimens and five cell lines was detected by qRT-PCR. CCK-8, colony formation, and flow cytometry assays were conducted to study the cell viabilities of EOC cells. Wound scratch and transwell analyses were carried out for the examination of cell invasion and migration of EOC cells. The targeting associations between LINC00958 and STAT1 were demonstrated by ChIP analyses combined with luciferase reporter assays. The related proteins of Wnt/β-catenin signaling were determined using RT-PCR.

Results

Higher levels of LINC00958 were observed in EOC tissues and cell lines. Our data also revealed that high LINC00958 expression was partly induced by STAT1. Functionally, knockdown of LINC00958 suppressed the proliferation, migration, and invasion of EOC cells. Mechanistic investigation showed that the inhibitory effect of LINC00958 knockdown on EOC cells was mediated by the Wnt/β-catenin signaling.

Conclusion

Our findings suggested that STAT1-induced overexpression of LINC00958 promoted EOC progression by modulating Wnt/β-catenin signaling.

Assisted differential network analysis for gene expression data

In the analysis of gene expression data, when there are two or more disease conditions/groups (e.g., diseased and normal, responder and nonresponder, and multiple stages/subtypes), differential analysis has been extensively conducted to identify key differences and has important implications. Network analysis takes a system perspective and can be more informative than that limited to simple statistics such as mean and variance. In differential network analysis, a common practice is to first estimate a gene expression network for each condition/group, and then spectral clustering can be applied to the network difference(s) to identify key genes and biological mechanisms that lead to the differences. Compared to "simple" analysis such as regression, differential network analysis can be more challenging with the significantly larger number of parameters. In this study, taking advantage of the increasing popularity of multidimensional profiling data, we develop an assisted analysis strategy and propose incorporating regulator information to improve the identification of key genes (that lead to the differences in gene expression networks). An effective computational algorithm is developed. Comprehensive simulation is conducted, showing that the proposed approach can outperform the benchmark alternatives in identification accuracy. With the The Cancer Genome Atlas lung adenocarcinoma data, we analyze the expressions of genes in the KEGG cell cycle pathway, assisted by copy number variation data. The proposed assisted analysis leads to identification results similar to the alternatives but different estimations. Overall, this study can deliver an efficient and cost-effective way of improving differential network analysis.

LncRNA CASC2 inhibits lung adenocarcinoma progression through forming feedback loop with miR-21/p53 axis

Lung adenocarcinoma (LUAD) is the most common type of lung cancer. Currently, the survival rate of LUAD patients remains low due to heterogeneity and high invasiveness. The long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is reported to be related to LUAD development. Hence, we investigate the roles and regulatory mechanism of CASC2 in LUAD. The expression levels of CASC2, microRNA (miR)-21, and p53 were quantified by quantitative real-time polymerase chain reaction, and the protein levels of Bax, Bcl-2, p53, and p21 were examined using western blotting. A dual-luciferase reporter experiment was conducted to prove the molecular interactions between CASC2 and miR-21 or p53. CCK-8 and flow cytometry assays were conducted to assess cell proliferation and apoptosis, respectively. CASC2 was expressed at a low level in LUAD patients and LUAD cell lines. CASC2 overexpression markedly suppressed cell proliferation and enhanced apoptosis. Mechanistically, CASC2 overexpression dramatically inhibited miR-21 expression and increased p53 expression by directly targeting miR-21. Moreover, rescue experiments suggested that either miR-21 overexpression or p53 silencing obviously weakened the biological effects of CASC2 overexpression. In addition, p53 was proven to be an upstream transcription factor of CASC2 and can activate CASC2 transcription. These results provide evidence that the lncRNA CASC2/miR-21/p53 form a positive feedback loop to mediate cell proliferation and apoptosis in LUAD, which may provide a new insight into the pathological mechanisms of LUAD.

ETS like-1 protein ELK1-induced lncRNA LINC01638 accelerates the progression of papillary thyroid cancer by regulating Axin2 through Wnt/β-catenin signaling pathway

Papillary thyroid carcinoma (PTC) characterized by distant metastasis is a major public health issue among women worldwide. LncRNA LINC01638 is reportedly a critical oncogene in the development of certain cancers. However, the biological function of LINC01638 in PTC is currently unclear. The goal of this study was to identify LINC01638 expression level and its role in PTC progression. The expression of LINC01638 was detected applying qRT-PCR. CCK-8 assay, colony formation assay, immunofluorescence staining and flow cytometric analysis were performed to assess cell proliferation and cell cycle. In addition, cell migration and invasion were examined via wound healing assay, transwell assay and western blot analysis. We found that LINC0163 was upregulated in PTC cells compared with normal thyroid gland epithelial cell line Nthy-ori3-1. ELK1 could act as a transcription factor of LINC01638 and induce LINC01638 expression. LINC01638 silencing inhibited cell proliferation, migration and invasion, and obstructed the progress of TPC-1 cell cycle. LINC0163 silencing activated Axin2 while suppressing the expressions of β-catenin, Cyclin-D1 and c-MYC. Rescue experiment utilizing the transfection of Axin2 overexpression plasmid weakened LINC01638 overexpression-enhanced TPC-1 cell proliferation, metastasis, cell cycle progress and Wnt/β-catenin pathway. These results indicate that LINC0163 regulates PTC progression via inhibition of Wnt/β-catenin and activation of Axin2, which may develop into a novel therapeutic strategy for PTC treatment.

There and Back Again: Hox Clusters Use Both DNA Strands

Bilaterian animals operate the clusters of Hox genes through a rich repertoire of diverse mechanisms. In this review, we will summarize and analyze the accumulated data concerning long non-coding RNAs (lncRNAs) that are transcribed from sense (coding) DNA strands of Hox clusters. It was shown that antisense regulatory RNAs control the work of Hox genes in cis and trans, participate in the establishment and maintenance of the epigenetic code of Hox loci, and can even serve as a source of regulatory peptides that switch cellular energetic metabolism. Moreover, these molecules can be considered as a force that consolidates the cluster into a single whole. We will discuss the examples of antisense transcription of Hox genes in well-studied systems (cell cultures, morphogenesis of vertebrates) and bear upon some interesting examples of antisense Hox RNAs in non-model Protostomia.

Silencing lncRNA HOXA10-AS decreases cell proliferation of oral cancer and HOXA10-antisense RNA can serve as a novel prognostic predictor

Objective

Long noncoding (lnc)RNAs regulate multiple biological processes including cancer. Oral squamous cell carcinoma (OSCC) is a common malignancy with poor prognosis. We aimed to identify the function of lncRNA HOXA10 antisense RNA (HOXA10-AS) and its clinical significance.

Methods

We used differential expression analysis to identify aberrantly expressed lncRNAs associated with OSCC. We identified key genes related to HOXA10-AS and their biological functions using bioinformatics tools and functional enrichment analyses. We predicted the function of HOXA10-AS using gene set enrichment and variation analyses and analyzed proliferation markers at the mRNA and protein levels. Finally, we silenced HOXA10-AS using antisense oligonucleotide and assessed proliferation ability using a cell counting kit (CCK8) and clone formation assays.

Results

In total, 506 aberrantly expressed lncRNAs were identified. HOXA10-AS was identified as a risk factor for OSCC and its expression was positively associated with tumor grade. We identified hub genes involved in regulating proliferation and predicted that HOXA10-AS is associated with an active cell cycle and increased proliferation. Silencing HOXA10-AS decreased proliferation in OSCC cell lines.

Conclusions

HOXA10-AS is involved in cell proliferation and silencing it decreases proliferation. Thus, HOXA10-AS could serve as prognostic biomarker and therapeutic target for OSCC.

Prognostic Value and Related Regulatory Networks of MRPL15 in Non-Small-Cell Lung Cancer

Background

Mitochondrial ribosomal protein L15 (MRPL15), a member of mitochondrial ribosomal proteins whose abnormal expression is related to tumorigenesis. However, the prognostic value and regulatory mechanisms of MRPL15 in non-small-cell lung cancer (NSCLC) remain unclear.

Methods

GEPIA, ONCOMINE, Gene Expression Omnibus (GEO), UALCAN, Kaplan–Meier plotter, PrognoScan, LinkedOmics and GeneMANIA database were utilized to explore the expression and prognostic value of MRPL15 in NSCLC. Additionally, immune infiltration patterns were evaluated via ESTIMATE algorithm and TISIDB database. Furthermore, the expression and prognostic value of MRPL15 in lung cancer were validated via immunohistochemistry (IHC) assays.

Results

In NSCLC, multiple cohorts including GEPIA, ONCOMINE and 8 GEO series (GSE8569, GSE101929, GSE33532, GSE27262, GSE21933, GSE19804, GSE19188, GSE18842) described that MRPL15 was up-regulated. Moreover, MRPL15 was notably linked to gender, clinical stage, lymph node status and the TP53 mutation status. And patients with high MRPL15 expression showed poor overall survival (OS), progression-free survival (PFS), disease-free survival (DFS) and relapse-free survival (RFS) in NSCLC. Then, functional network analysis suggested that MRPL15 participated in metabolism-related pathways, DNA replication and cell cycle signaling via pathways involving several kinases, miRNAs and transcription factors. Additionally, it was found that MRPL15 expression was negatively related to immune infiltration, including immune scores, stromal scores and several tumor-infiltrating lymphocytes (TILs). Furthermore, IHC results further confirmed the high MRPL15 expression and its prognostic potential in lung cancer.

Conclusions

These findings demonstrate that high MRPL15 expression indicates poor prognosis in NSCLC and reveal potential regulatory networks as well as the negative relationship with immune infiltration. Thus, MRPL15 may be an attractive predictor and therapeutic strategy for NSCLC.

STAT3 activates the transcription of lncRNA NR2F1-AS1 to promote the progression of melanoma via regulating the miR-493-5p/GOLM1 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) are vital regulators during the biological processes of melanoma. The present study aimed to uncover biological functions of lncRNA termed NR2F1 antisense RNA 1 (NR2F1-AS1) in melanoma and the potential mechanisms.

METHODS

Relative levels of NR2F1-AS1 and miR-493-5p in a total of 137 paired primary melanoma tissues and corresponding non-tumor tissues, as well as three melanoma cell lines, were examined by a real-time polymerase chain reaction. The clinical significance of NR2F1-AS1 expression was analyzed statistically. The STAT3 binding motif in the promoter region of NR2F1-AS1 was identified by JASPAR (http://jaspar.genereg.net). The association between STAT3 and NR2F1-AS1 was determined by dual-luciferase reporter and chromatin immunoprecipitation assays. The effects of NR2F1-AS1 on cell proliferation, migration and were measured by cell counting kit-8 (CCK-8), Edu, transwell and wound healing assays. Dual-luciferase reporter and RNA pull-down assays were applied to validate the interaction among NR2F1-AS1, miR-493-5p and GOLM1. Furthermore, in vivo experiments were conducted to demonstrate the oncogenic role of NR2F1-AS1 in melanoma.

RESULTS

Up-regulated NR2F1-AS1 and down-regulated miR-493-5p were detected in melanoma tumors and cells. The overexpression of NR2F1-AS1 was induced by STAT3. High NR2F1-AS1 expression was correlated to advanced tumor stage and poor prognosis of melanoma. Functional studies using CCK-8, Edu, transwell and wound healing assays revealed that the proliferative, migratory and invasive capacities of melanoma cells were attenuated by the by inhibition of NR2F1-AS1. Moreover, NR2F1-AS1 was able to up-regulate GOLM1 through recognizing and binding miR-493-5p. Furthermore, knockdown of miR-493-5p distinctly reversed these inhibitory effects of NR2F1-AS1 down-regulation on the tumorigenesis and progression of melanoma.

CONCLUSIONS

Our findings demonstrate a key role for NR2F1-AS1 in melanoma progression via targeting miR-493-5p/GOLM1 axis.

Promotive effects of HOXA10 antisense RNA on the stemness of oral squamous cell carcinoma stem cells through a microRNA-29a/MCL-1/phosphatidyl inositol 3-kinase/protein kinase B axis

OBJECTIVE

The aim of this study was to investigate the effects of long non-coding RNA (lncRNA) HOXA10 antisense RNA (HOXA10-AS) on the properties of oral squamous cell carcinoma (OSCC) stem cells and the molecular mechanism.

DESIGN

Tumor and the paracancerous tissues were collected from 83 patients with OSCC. OSCC stem cells were extracted from a human OSCC cell line Tca8113. Silencing of HOXA10-AS was introduced in stem cells and then the malignant behaviors of cells were determined. The target transcripts of HOXA10-AS were predicted using integrated bioinformatics analyses. The interactions among HOXA10-AS, microRNA (miR)-29a and MCL-1 were validated, and their functions in stem cell behaviors in vivo and in vitro were explored.

RESULTS

HOXA10-AS and MCL-1 were highly expressed while miR-29a was poorly expressed in the collected tumor tissues and the extracted OSCC stem cells. High expression of HOXA10-AS and MCL-1, while poor expression of miR-29a was relevant to poor prognosis in patients. Silencing of HOXA10-AS suppressed proliferation and tumor sphere formation ability of stem cells, and it reduced growth and metastasis of tumors in animals. HOXA10-AS served as a sponge for miR-29a and upregulated MCL-1 mRNA expression. Inhibition of miR-29a promoted, while silencing of MCL-1 suppressed the malignant behaviors of OSCC stem cells. In addition, HOXA-10-AS and MCL-1 were found to activate the phosphatidyl inositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway.

CONCLUSION

This study evidenced that HOXA10-AS enhances the stem cell property of OSCC stem cells through the miR-29a/MCL-1/PI3K/AKT axis.

ELK1-induced upregulation lncRNA LINC02381 accelerates the osteosarcoma tumorigenesis through targeting CDCA4 via sponging miR-503-5p

Long noncoding RNAs (lncRNAs) have been identified as functional modulators in human tumors. The purpose of our study was to determine the expressing trend, clinical significance and functions of lncRNA LINC02381(LINC02381) in osteosarcoma. We observed that the expression of LINC02381 and cell division cycle-associated protein 4 (CDCA4) were distinctly increased in osteosarcoma specimens and cells, while miR-503-5p expression was decreased. Additionally, ETS transcription factor ELK1 (ELK1) could bind directly to the LINC02381 promoter region and activate its transcription. Clinical assays revealed that high LINC02381 was associated with advanced clinical progress and poor clinical outcome. Functionally, knockdown of LINC02381 suppressed the proliferation, migration and invasion of osteosarcoma cells. What's more, LINC02381 could down-regulate CDCA4 via sponging miR-503-5p, and there existed a negative correlation between LINC02381 expression and miR-503-5p expression in 92 osteosarcoma samples. Rescue experiments proved the carcinogenic role of LINC02381/miR-503-5p/CDCA4 axis in osteosarcoma progression. Overall, our data illustrated how LINC02381 played an oncogenic role in osteosarcoma and might offer a novel diagnostic and prognostic biomarker and potential therapeutic target for osteosarcoma.

HOXA10 promotion of HDAC1 underpins the development of lung adenocarcinoma through the DNMT1-KLF4 axis

Background

Previous research has highlighted the ability of Homeobox A10 (HOXA10) to the promote proliferation, migration, and epithelial-mesenchymal transformation of various cancers, including lung adenocarcinoma (LAD), which is characterized by an aggressive disease course that exhibits rapid proliferation and migration, with studies suggesting histone deacetylase 1 (HDAC1) to be a downstream mediator of HOXA10. The current study aimed to investigate the mechanism by which HOXA10-mediated HDAC1 influences the development of LAD.

Methods

The expression patterns of HOXA10, HDAC1, DNA methyltransferase 1 (DNMT1), and Kruppel-like factor 4 (KLF4) were determined. Additionally, the effect of HOXA10, HDAC1, or DNMT1 on invasive phenotypes of LAD was analyzed using depletion experiments. The interactions among HOXA10, HDAC1, DNMT1, and KLF4 were evaluated via chromatin immunoprecipitation, dual luciferase assay or co-immunoprecipitation. Furthermore, the tumorigenic ability of the LAD cells following HOXA10 silencing and/or HDAC1 overexpression in vivo was also investigated.

Results

In the LAD tissues and cells, HOXA10, HDAC1, and DNMT1 all exhibited high levels of expression, while KLF4 was poorly expressed. HOXA10 silencing inhibited the expression of HDAC1, reduced LAD cell proliferation, migration, and invasion, and promoted the apoptosis. HDAC1 promoted DNMT1 expression through deacetylation, and DNMT1 inhibited the KLF4 expression through DNA methyltransferase. The in vitro findings were further attested through the use of in vivo assays.

Conclusion

Taken together, the key observations of the current study highlight the role of HOXA10 and HDAC1 in promoting the proliferation and migration of LAD cells. HOXA10-induced upregulation of HDAC1 interacts with DNMT1-KLF4 axis, while the inhibition of HOXA10 or HDAC1 represents a promising anti-tumor therapy target for LAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01867-0.

Transcriptional network modulated by the prognostic signature transcription factors and their long noncoding RNA partners in primary prostate cancer

Background

Transcriptional regulators are seminal players in the onset and progression of prostate cancer. However, clarification of their underlying regulatory circuits and mechanisms demands considerable effort.

Methods

Integrated analyses were performed on genomic, transcriptomic, and clinicopathological profiles of primary prostate cancer and transcription factor-binding profiles, which included estimating transcription factor activity, identifying transcription factors of prognostic values, and discovering cis- and trans-regulations by long noncoding RNAs. Interactions between transcription factors and long noncoding RNAs were validated by RNA immunoprecipitation quantitative PCR. RNA interference assays were performed to explore roles of the selected transcription regulators.

Findings

Sixteen transcription factors, namely, ETS1, ARID4B, KLF12, GMEB1, HBP1, MXI1, MYC, MAX, PGR, BCL11A, AR, KLF4, SRF, HIF1A, EHF, and ATOH1, were jointly identified as a prognostic signature. Candidate long noncoding RNAs interplaying with the prognostic signature constituent transcription factors were further discovered. Their interactions were randomly checked, and many of them were experimentally proved. Transcription regulation by MYC and its long noncoding RNA partner AL590617.2 was further validated on their candidate targets. Moreover, the regulatory network governed by the transcription factors and their interacting long noncoding RNA partners is illustrated and stored in our LNCTRN database (https://navy.shinyapps.io/lnctrn).

Interpretation

The prognostic signature constituent transcription factors and their interacting long noncoding RNAs may represent promising biomarkers and/or therapeutic targets for prostate cancer. Furthermore, the computational framework proposed in the present study can be utilized to explore critical transcriptional regulators in other types of cancer.

Funding

This work was supported by National Natural Science Foundation of China and Fudan University.

YY1-mediated up-regulation of lncRNA LINC00466 facilitates glioma progression via miR-508/CHEK1

BACKGROUND

The abnormal expression of lncRNA LINC00466 (LINC00466) has been demonstrated in several tumor types. However, the expression pattern and functions of LINC00466 in glioma remain uninvestigated.

METHODS

A reverse transcriptase-polymerase chain reaction (RT-PCR) was utilized to analyze LINC00466 in human glioma tissues and cell lines. Luciferase reporter assays were performed to explore whether YY1 could bind to the promoter region of LINC00466. Cell counting kit-8, flow cytometry, colony-formation, transwell migration and invasion assays were carried out to determine the involvement of INC00466 in glioma. Luciferase assays and pulldown assays were conducted to verify the binding sites.

RESULTS

We report that LINC00466 expression is increased in glioma cells and tissues. YY1 transcription factor (YY1) can bind directly to the LINC00466 promoter region. Clinical studies revealed that the elevated expression of LINC00466 is closely correlated with an advanced World Health Organization grade (p = 0.008), Karnofsky Performance Status score (p = 0.004) and a short overall survival (p = 0.0035) of glioma patients. Functional assays revealed that LINC00466 knockdown distinctly suppresses glioma cell proliferation, migration, invasion and epithelial-mesenchymal progress, and also promotes apoptosis. Moreover, dual-luciferase reporter assays indicated that LINC00466 acts as an endogenous sponge via binding to miR-508 and decreasing its expression. Luciferase assays and RT-PCR assays demonstrated that checkpoint kinase 1 (CHEK1) is a target of miR-508, and LINC00466 modulates CHEK1 levels by competing for miR-508. LINC00466 may exhibit its anti-oncogenic roles through targeting the miR-508/CHEK1 axis.

CONCLUSIONS

Our findings identified a novel glioma-related long non-coding RNA, LINC00466, which may provide a potential novel prognostic and therapeutic target for glioma.

A LHFPL3-AS1/miR-580-3p/STAT3 Feedback Loop Promotes the Malignancy in Melanoma via Activation of JAK2/STAT3 Signaling

Melanoma is one of the severe skin cancers, accounting for three fourths of all deaths caused by skin cancers and gathering attention from researchers. Previous studies have elucidated that long noncoding RNAs (lncRNA) engage actively in tissue physiology and disease development, especially in tumorigenesis. LncRNA LHFPL3 antisense RNA 1 (LHFPL3-AS1) has rarely been mentioned in researches regarding cancers; therefore, the underlying role and function of LHFPL3-AS1 in melanoma arouse our interest. Data from our work suggested that LHFPL3-AS1 expression was markedly elevated in melanoma tissues and cells. Of note, patients with melanoma with high level of LHFPL3-AS1 were burdened with unfavorable prognosis. Functionally, it has been revealed that LHFPL3-AS1 exerted pro-growth, pro-invasion, and pro-EMT functions in melanoma. Mechanistically, it was figured out that LHFPL3-AS1 could be transcriptionally activated by STAT3. In turn, LHFPL3-AS1 served as a sponge of miR-580-3p to augment STAT3 expression, resulting in activated JAK2/STAT3 signaling pathway in melanoma. IMPLICATIONS: Our study revealed a novel positive feedback loop LHFPL3-AS1/miR-580-3p/STAT3 in melanoma, which might contribute to finding potential therapeutic targets for melanoma.

Identification of methylation-driven genes related to the prognosis of papillary renal cell carcinoma: a study based on The Cancer Genome Atlas

BACKGROUND

Aberrant DNA methylation patterns are involved in the pathogenesis of papillary renal cell carcinoma (pRCC). This study aimed to investigate the potential of methylation-driven genes as biomarkers in determining the prognosis of pRCC by bioinformatics analysis.

METHODS

DNA methylation and transcriptome profiling data were downloaded from The Cancer Genome Atlas database. Methylation-driven genes (MDGs) were obtained using MethylMix R package. A Cox regression model was used to screen for pRCC prognosis-related MDGs, and a linear risk model based on MDG methylation profiles was constructed. A combined methylation and gene expression survival analysis was performed to further explore the prognostic value of MDGs independently.

RESULTS

A total of 31 MDGs were obtained. Univariate and multivariate Cox regression analysis identified eight genes (CASP1, CD68, HOXD3, HHLA2, HOXD9, HOXA10-AS, TMEM71, and PLA2G16), which were used to construct a predictive model associated with overall survival in pRCC patients. Combined DNA methylation and gene expression survival analysis revealed that C19orf33, GGT6, GIPC2, HHLA2, HOXD3, HSD17B14, PLA2G16, and TMEM71 were significantly associated with patients' survival.

CONCLUSION

Through the analysis of MDGs in pRCC, this study identified potential biomarkers for precision treatment and prognosis prediction, and provided the basis for future research into the molecular mechanism of pRCC.

Roles of Wnt/β-Catenin Signaling Pathway Regulatory Long Non-Coding RNAs in the Pathogenesis of Non-Small Cell Lung Cancer

Lung cancer is one of the leading causes of cancer-related mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common pathological type of lung cancer. Long non-coding RNAs (lncRNAs) are promising novel diagnostic and prognostic biomarkers, as well as potential therapeutic targets for lung cancer. Long non-coding RNAs (lncRNAs) have been demonstrated to modulate tumor cells proliferation, cell cycle progression, invasion, and metastasis by regulating gene expression at transcriptional, post-transcriptional, and epigenetic levels. The oncogenic aberrant Wnt/β-catenin signaling is prominent in lung cancer, playing a vital role in tumorigenesis, prognosis, and resistance to therapy. Interestingly, compelling studies have demonstrated that lncRNAs exert either oncogenic or tumor suppressor roles by regulating Wnt/β-catenin signaling. In this review, we aim to present the current accumulated knowledge regarding the roles of Wnt/β-catenin signaling-regulated lncRNAs in the pathogenesis of non-small cell lung cancer (NSCLC). Better understanding of the effects of lncRNAs on Wnt/β-catenin signaling might contribute to the improved understanding of the molecular tumor pathogenesis and to the uncovering of novel therapeutic targets in NSCLC.

SP1-mediated upregulation of lncRNA SNHG4 functions as a ceRNA for miR-377 to facilitate prostate cancer progression through regulation of ZIC5

BACKGROUND/AIMS

Long noncoding RNAs (lncRNAs) have been demonstrated to serve distinct roles in human tumorigenesis. Previous studies have found that lncRNA small nucleolar RNA host gene 4 (SNHG4) was dysregulated in several tumors. However, the expression, clinical significances, and action mechanisms of SNHG4 in prostate cancer (PCa) are still unclear.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to detect SNHG4 expression in tissue samples and PCa cells. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine, clonogenic formation, wound-healing, and transwell invasion assays were, respectively, used to evaluate cell proliferation, colony formation ability, migration, and invasion. Flow cytometric analysis was applied to assess cell apoptosis. Chromatin immunoprecipitation assays were conducted to determine the binding between SP1 and SNHG4 promoter. Luciferase reporter assay, qRT-PCR, and western blot analysis were carried out to explore and confirm the interaction among SNHG4, miR-377, and ZIC5.

RESULTS

SNHG4 was highly expressed in PCa and its upregulation was induced by transcription factor SP1. The high levels of SNHG4 were distinctly associated with tumor stage, lymph node metastasis, and reduced overall survival of patients with PCa. SNHG4 knockdown inhibited the growth, migration, and invasion of PCa cells. In addition, miR-377 was a target of SNHG4 and ZIC5 was a target gene of miR-377 in PCa. SNHG4 promoted ZIC5-mediated growth and metastasis through modulating miR-377.

CONCLUSION

Our findings illuminate how SNHG4 formed a regulatory network to display a tumor-promotive effect in PCa and revealed that SNHG4 may be a novel therapeutic target and prognostic marker for patients with PCa.

Targeted overexpression of the long noncoding RNA ODSM can regulate osteoblast function in vitro and in vivo

Ameliorating bone loss caused by mechanical unloading is a substantial clinical challenge, and the role of noncoding RNAs in this process has attracted increasing attention. In this study, we found that the long noncoding RNA osteoblast differentiation-related lncRNA under simulated microgravity (lncRNA ODSM) could inhibit osteoblast apoptosis and promote osteoblast mineralization in vitro. The increased expression level of the lncRNA ODSM partially reduced apoptosis and promoted differentiation in MC3T3-E1 cells under microgravity unloading conditions, and the effect was partially dependent on miR-139-3p. LncRNA ODSM supplementation in hindlimb-unloaded mice caused a decrease in the number of apoptotic cells in bone tissue and an increase in osteoblast activity. Furthermore, targeted overexpression of the lncRNA ODSM in osteoblasts partially reversed bone loss induced by mechanical unloading at the microstructural and biomechanical levels. These findings are the first to suggest the potential value of the lncRNA ODSM in osteoporosis therapy and the treatment of pathological osteopenia.

Function and regulation annotation of up-regulated long non-coding RNA LINC01234 in gastric cancer

Background

Accumulated evidences indicate that long non‐coding RNAs (lncRNAs) participate in many biological mechanisms. Moreover, it acts as an essential regulator in various human diseases such as gastric cancer (GC). Nevertheless, the comprehensive regulatory roles and clinical significance of most lncRNAs in GC are not fully understood.

Methods

In this research, our aim was to investigate the underlying mechanism of lncRNA LINC01234 in GC. Firstly, the usage of qRT‐PCR helped to establish expression pattern of LINC01234 in GC tissues. Following this, appropriate statistical tests were applied to analyze the relation between expression level and clinicopathological factors. Ultimately, potential functions and regulatory network of LINC01234 were concluded via GSEA and a series of bioinformatics tools or databases, respectively.

Results

Consequently, at the end of research we found LINC01234 is up‐regulated in GC tissues in comparison with adjacent normal tissues. Furthermore, its expression level is correlated with differentiation of patients with GC. It is also important to highlight bioinformatics analysis revealed that LINC01234 is involved in cancer‐associated pathways such as cell cycle and mismatch repair. Also, regulatory network of LINC01234 presented a probability in the involvement of tumorigenesis through regulating cancer‐associated genes.

Conclusion

Overall, our results suggested that LINC01234 may play a crucial role in GC.

SOX2-induced upregulation of lncRNA LINC01561 promotes non-small-cell lung carcinoma progression by sponging miR-760 to modulate SHCBP1 expression

Long noncoding RNAs (lncRNAs) have been shown to have critical regulatory roles in tumorigenesis. lncRNA LINC01561 (LINC01561) is a newly identified tumor-related lncRNA and its dysregulation has been demonstrated in several tumors. However, whether LINC01561 is involved in the progression of non-small-cell lung carcinoma (NSCLC) and its underlying mechanisms remain unknown. In this study, we first provided evidence that LINC01561 expressions were distinctly upregulated in NSCLC tissues and cell lines. Combining with bioinformatics assays and mechanism experiments, our group demonstrated that LINC01561 was activated by SOX2 in NSCLC. Clinical research revealed that upregulation of LINC01561 was related to poorer clinicopathologic features and shorter survival time. Functionally, suppression of LINC01561 exhibited tumor-suppressive functions through impairing cell proliferation, migration, and invasion as well as inducing apoptosis. Moreover, we verified that LINC01561 could directly bind to miR-760, isolating miR-760 from its target gene SHC SH2 domain-binding protein 1 (SHCBP1). We also found that SHCBP1 was lowly expressed in NSCLC and served as a tumor promoter. A functional study indicated that LINC01561 regulated SHCBP1 expression by competitively binding to miR-760. In summary, our findings indicated that SOX2-induced overexpression of LINC01561 promoted the proliferation and metastasis by acting as a competing endogenous RNA to modulate SHCBP1 by sponging miR-760.

Long non-coding RNAE330013P06 promotes progression of breast cancer with type 2 diabetes

Background

In previous research, we found diabetes rather than obesity was an independent risk factor of breast cancer. However, why diabetes could lead to increased risk of breast cancer patients remains elusive. Long non‐coding RNAE330013P06 has been shown to be upregulated in diabetes, and long non‐coding RNAs generally promote progression of cancer.

Methods

About 200 specimens of breast patients were obtained in previous clinical trial; 34 samples diagnosed as type 2 diabetes in breast cancer patient were enrolled in this research. Blood samples from 36 patients diagnosed as breast cancer without diabetes; 35 diabetic patients and 35 healthy peoples were obtained as control. All blood samples were measured by quantitative real‐time PCR (qRT‐PCR). Invasion and migration were tested by Transwell assay. Cell proliferation assay was tested by CCK‐8. Protein analysis was determined by Western blot.

Results

Compared with breast cancer patients without diabetes, diabetic patients without breast cancer and healthy peoples, LncRNAE330013P06 was upregulated in breast cancer patient with diabetes. Furthermore, of 34 breast patients, high LncRNAE330013P06 expression was significantly associated with family history, tumor‐node‐metastasis stage and lymph node metastasis. E33 promoted cancer cell growth in vitro via downregulation of P53.

Conclusion

Upregulation of LncRNAE330013P06 driven by type 2 diabetes is one of the factors which promoted progression of breast cancer.

Tumor-Promoting Activity of Long Noncoding RNA LINC00466 in Lung Adenocarcinoma via miR-144-Regulated HOXA10 Axis

Previous investigations have implicated long noncoding RNAs in lung adenocarcinoma, which is an aggressive disease with poor prognosis and high mortality. Through the alteration of lung adenocarcinoma-related long noncoding RNA and miRNA based on microarray analysis, our aim was to understand the role of LINC00466 and miR-144 in lung adenocarcinoma progression. The relationship among LINC00466, miR-144, and HOXA10 was also verified. Moreover, to examine whether the LINC00466/miR-144/HOXA10 axis contributed to the cellular processes in lung adenocarcinoma, A549 and XWLC-05 cells were transduced with siRNA LINC00466, siRNA HOXA10, or miR-144 mimic plasmids. Highly expressed LINC00466 and HOXA10 and lowly expressed miR-144 were eventually revealed in lung adenocarcinoma tissues. HOXA10 was down-regulated in response to the overexpression of miR-144, whereas inhibition of LINC00466 decreased its binding to miR-144, thereby up-regulating miR-144, which, in turn, halted the lung adenocarcinoma progression. LINC00466 silencing or miR-144 up-regulation exerted an inhibitory role in the tumorigenicity, invasion, migration, and proliferation, and it also promoted apoptosis of lung adenocarcinoma cells. Furthermore, tumor formation was inhibited by knockdown of LINC00466 or overexpression of miR-144. Taken together, LINC00466 could restrain the miR-144 expression to up-regulate HOXA10 and, therefore, promote lung adenocarcinoma.

HOX cluster-embedded antisense long non-coding RNAs in lung cancer

Homeobox (HOX) genes play vital roles in embryonic development and oncogenesis. In humans, there are 39 HOX genes found in four clusters that are located on different chromosomes. The HOX clusters also contain numerous non-protein-coding RNAs, including some lncRNAs. The HOX cluster-embedded lncRNAs (HOX-lncRNAs), most notably, HOTTIP and HOTAIR play a major role in the regulation of their adjacent coding genes. Recently, most HOX-lncRNAs have been shown to impact tumorigenesis and cancer progression. Several HOX-lncRNAs, including HOTTIP, HOXA11-AS, HOTAIRM1, HOXA-AS3, HOXA10-AS, HOTAIR, and HAGLR, are dysregulated in lung cancer. Moreover, their expression levels are correlated with the clinical features of this disease. These HOX-lncRNAs regulate the proliferation, invasion, migration, and chemo-resistance of lung cancer cells through various molecular mechanisms. Although lncRNAs have received much attention lately, the functions of some HOX-lncRNAs in the development of cancer are unclear. Thus, HOX-embedded lncRNAs should be widely investigated in cancer. Here, we review the functions of HOX-lncRNAs in lung cancer.

ELK1-induced upregulation of lncRNA TRPM2-AS promotes tumor progression in gastric cancer by regulating miR-195/ HMGA1 axis

Long noncoding RNAs (lncRNAs) have been confirmed to be aberrantly expressed in various diseases including tumors. Recently, a new tumor-related lncRNA, lncRNA TRPM2 antisense RNA (TRPM2-AS), was shown to be involved in many tumors, such as lung cancer and breast cancer. However, the expression and role of TRPM2-AS in the development of gastric cancer (GC) have not been elucidated. In the current study, we provided evidence that the expression levels of TRPM2-AS were increased in both GC tissues and cell lines. We also showed that overexpression of TRPM2-AS was modulated by ELK1, a transcription factor. The results of clinical assays showed that higher expressions of TRPM2-AS were significantly related with invasion depth, TNM stage, lymphatic metastasis, and shorter overall survival. Further clinical assays using multivariate analysis suggested that TRPM2-AS expression was an independent prognostic factor in patients with GC. Functional experiments illustrated that depression of TRPM2-AS suppressed proliferation, migration, and invasion in GC cells. In terms of mechanism, we found that TRPM2-AS directly inhibited miR-195, which targeted the 3'-untranslated region of high-mobility group AT-hook 1 (HMGA1) messenger RNA. Overall, these findings revealed that ELK1-induced overexpression of TRPM2-AS promoted the development and progression of GC in part through miR-195/HMGA1 signaling axis, and established its candidacy as a new cancer biomarker for GC patients.

SP1-induced upregulation of long non-coding RNA HCP5 promotes the development of osteosarcoma

Long non-coding RNAs (LncRNAs) are acknowledged as crucial regulators in tumorigenesis and tumor progression. In this study, we explored the mechanism and function of lncRNA HCP5 in osteosarcoma (OS). At first, five lncRNAs were chosen from GeneCard and subjected to qRT-PCR examination. The results indicated that HCP5 was significantly overexpressed in four OS cell lines. Northern blot assay further proved the higher expression of HCP5 in OS cell lines. To identify the biological role of HCP5 in OS, we silenced the expression of HCP5 in U2OS and MG-63 cells which possessed the highest level of HCP5. CCK-8 and colony formation assay revealed the inhibitory effect of HCP5 knockdown on cell proliferation. Cell apoptosis was found to be increased in cells transfected with sh-HCP5#1. Moreover, cell invasion and epithelial-mesenchymal transition (EMT) were reversed by the silencing of HCP5. The results of functional assays showed that HCP5 acted as an oncogene in osteosarcoma. Mechanically, HCP5 was found to be activated by the transcription factor SP1. Finally, rescue assays were conducted to demonstrate the function of SP1/HCP5 axis in osteosarcoma. In conclusion, we confirmed that SP1-induced upregulation of long non-coding RNA HCP5 promotes the development of osteosarcoma.

Identification of a 26-lncRNAs Risk Model for Predicting Overall Survival of Cervical Squamous Cell Carcinoma Based on Integrated Bioinformatics Analysis

As a common malignancy in women, cervical squamous cell carcinoma is a major cause of cancer-related mortality globally. Recent studies have demonstrated that long non-coding RNA (lncRNA) can function as potential biomarkers in cancer prognosis; however, little is known about its role in cervical cancer. In this study, we downloaded the gene expression profiles along with the clinical data of patients with cervical squamous cell carcinoma from The Cancer Genome Atlas. By applying bioinformatics analysis including random forest selection and Least Absolute Shrinkage and Selection Operator (LASSO) cox regression model along with 10-fold cross-validation, we constructed a 26-lncRNAs risk model that can be used to predict the overall survival of cervical squamous cell carcinoma. After that, Kaplan-Meier analysis combined with log-rank p test was applied to assess the predictive accuracy of the 26-lncRNAs risk model. Further analysis showed that the prognostic value of 26-lncRNAs risk model was independent of other clinicopathological factors. At last, lncRNAs in the model were put into gene ontology biological process enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways analysis, which suggested that these lncRNAs might contribute to cancer-associated processes such as cell cycle and apoptosis. This study indicated that lncRNAs signature could be a useful marker to predict the prognosis of cervical squamous cell carcinoma.

LncRNA TP73-AS1 promoted the progression of lung adenocarcinoma via PI3K/AKT pathway

Lung adenocarcinoma (LAD) is one of the most common malignancies that threats human health worldwide. Long non-coding RNAs (lncRNAs) have been reported to play significant roles in tumorigenesis and might be novel biomarkers and targets for diagnosis and treatment of cancers. TP73-AS1 is a newly discovered lncRNA involved in the tumorigenesis and development of several cancers. However, its role in LAD has not been investigated yet. In the present study, we first found that TP73-AS1 expression was markedly increased in LAD tissues and cell lines and its overexpression was strongly associated with poor clinical outcomes. Then the loss/gain-of-function assays elucidated that TP73-AS1 contributed to cell proliferation, migration, and invasion in vitro, and the in vivo experiments illustrated that its knockdown inhibited tumor growth and metastasis. What was more, we discovered that phosphoinositide 3-kinase and AKT (PI3K/AKT) pathway was activated both in LAD tissues and cell lines but inactivated under TP73-AS1 silence. Moreover, the activation of this pathway could rescue the inhibitory effects of TP73-AS1 suppression on LAD cellular processes partially. These data suggested that TP73-AS1 served as an oncogene in LAD partially through activating PI3K/AKT pathway and it could be a potential target for diagnosis and treatment of LAD.

ELK1-induced upregulation of long non-coding RNA MIR100HG predicts poor prognosis and promotes the progression of osteosarcoma by epigenetically silencing LATS1 and LATS2

Osteosarcoma (OS) is the commonest malignant bone tumor in the world. High incidence of OS has gradually become a social problem. Recent years, numerous studies have revealed that long non-coding RNAs (lncRNAs) are crucial regulators in the tumor progression. As a member of lncRNA family, MIR100HG has been reported to be an oncogene in breast cancer and acute megakaryoblastic leukemia. Nevertheless, the specific role of MIR100HG in osteosarcoma is still unclear. In this study, we investigated the biological function and molecular mechanism of MIR100HG in the progression of osteosarcoma. At first, we measured the high expression of MIR100HG in OS tissues and cell lines by qRT-PCR. Kaplan-Meier method revealed that high expression of MIR100HG is a factor for the poor prognosis of OS patients (P = 0.004). To explore the effect of MIR100HG on the biological processes of OS, loss-of-function assays were conducted in OS cells. Functionally, MIR100HG knockdown suppressed cell proliferation, cell cycle progression while promoted cell apoptosis. Mechanistically, MIR100HG was upregulated by the transcription factor ELK1. The upregulation of MIR100HG led to the inactivation of Hippo pathway. Furthermore, we found that MIR100HG inactivated Hippo pathway in OS cells by epigenetically silencing LATS1 and LATS2. Rescue assays demonstrated that LATS1/2 involved in MIR100HG-mediated OS progression. In summary, our study indicated that ELK1-induced upregulation of MIR100HG promoted OS progression by epigenetically silencing LATS1 and LATS2 and inactivating Hippo pathway.