LINC00355 Promotes Tumor Progression in HNSCC by Hindering MicroRNA-195-Mediated Suppression of HOXA10 Expression

MAGI2-AS3 hypermethylated in promoter region promotes migration and invasion of head and neck squamous cell carcinoma via miRNA-31-5p/AR axis

Molecular regulatory mechanism of MAGI2-AS3 in HNSCC is not yet mature.In this study, we analyzed the methylation level of MAGI2-AS3 promoter and its downstream miR-31-5p/AR axis by bioinformatics methods. qRT-PCR was used to detect the mRNA expression level of each gene, and western blot was used to detect the expression level of AR proteins in tissues and cells. CCK-8, colony formation, wound healing, and cellular invasion assays were used to detect the HNSCC cell proliferation, migration, and invasion. Dual luciferase and RIP assays were performed to validate the binding relationship between genes. The effect of MAGI2-AS3 on HNSCC progression was verified in nude mice in vivo. The low expression of MAGI2-AS3 in HNSCC was caused by hypermethylation of MAGI2-AS3, which could regulate the target of miR-31-5p by sponge adsorption of miR-31-5p, and miR-31-5p could inhibit the expression of AR by directly targeting AR. Thus, MAGI2-AS3 could inhibit the proliferation, migration, and invasion of HNSCC through the miR-31-5p/AR axis. This provided a theoretical basis that MAGI2-AS3 was a potential therapeutic target for HNSCC.

Identification of IGF2BP2 and long non-coding RNA TUG1 for the prognosis and tumour microenvironment in head and neck squamous cell carcinoma

Objective

This study aimed to investigate the role of m6A-related long non-coding RNAs (lncRNAs) in the prognosis and tumour microenvironment of head and neck squamous cell carcinoma (HNSCC).

Methods

497 samples from The Cancer Genome Atlas were analysed to identify m6A-related lncRNAs via correlation models. Tripartite regression models, Kaplan-Meier analysis and nomograms were then utilised to assess the prognostic significance of these lncRNAs. Tumour mutation burden and immune cell infiltration analyses were also performed. Moreover, m6A-related lncRNAs expression and relation with IGF2BP2 were confirmed by RT-qPCR.

Results

The risk model revealed that high-risk scores predicted poorer survival outcomes. The area under ROC curves for predicting 1-, 3-, 5-year survival in the training set were 0.70, 0.68, and 0.64, respectively. Seven key m6A-related lncRNAs showed associations with immune checkpoint molecules, especially CTLA4 and PD-1. Finally, we found that knockdown of TUG1 repressed the expression of IGF2BP2.

Conclusions

Our results suggest that the m6A-related lncRNA risk model has potential clinical utility in predicting prognosis and immunotherapeutic responses in patients with HNSCC. Identification of candidate compounds for immunotherapy further emphasises the model's relevance in guiding treatment decisions for HNSCC.

Cancer-associated fibroblast exosome LINC00355 promotes epithelial-mesenchymal transition and chemoresistance in colorectal cancer through the miR-34b-5p/CRKL axis

This study was designed to investigate the role and mechanism of cancer-associated fibroblasts (CAFs)-derived exosomes (CAFs-exo) in metastatic and chemoresistant colorectal cancer (CRC). First, CAFs and normal fibroblasts (NFs) were isolated from CRC tissues and histologically normal adjacent tissues. Then, CAFs-exo and NFs-exo were separated with the help of ultracentrifugation. Next, the morphology, diameter and marker expression of exos were evaluated by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blot, respectively. Besides, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression levels of LINC00355, miR-34b-5p, and CRKL in clinical tissue samples, CRC cells, fibroblasts and exos; MTT assay and cell colony formation assay to assess the chemoresistance and colony formation ability of CRC cells, respectively. Subsequently, the targeting relationship among LINC00355, miR-34b-5p, and CRKL (a target gene of miR-34b-5p) was verified by Luciferase reporter assay; and the binding relationship between LINC00355 and miR-34b-5p was assessed by a pull-down assay. Finally, the expression of epithelial-mesenchymal transition (EMT)-related proteins, and CRKL in cells or exos were detected using western blot. After a series of treatments, CAFs and NFs, CAFs-exo and NFs-exo were successfully isolated and identified. It could be observed that CAFs-exo promoted EMT, colony formation and multidrug resistance in CRC cells by secreting LINC00355. Further studies demonstrated that CAFs-exo-secreted LINC00355 increased the expression of CRKL via inhibiting the expression of miR-34b-5p, thereby enhancing chemoresistance and promoting EMT progression in CRC cells. Collectively, CAFs-exo-derived LINC00355 promotes EMT and chemoresistance in CRC by regulating the miR-34b-5p/CRKL axis.

Is HOXA5 a Novel Prognostic Biomarker for Uterine Corpus Endometrioid Adenocarcinoma?

Endometrial cancer (EC) is one of the most pervasive malignancies in females worldwide. HOXA5 is a member of the homeobox (HOX) family and encodes the HOXA5 protein. HOXA5 is associated with various cancers; however, its association with EC remains unclear. This study aimed to determine the association between HOXA5 gene expression and the prognosis of endometrioid adenocarcinoma, a subtype of EC (EAEC). Microarray data of HOXA5 were collected from the Gene Expression Omnibus datasets, consisting of 79 samples from GSE17025 and 20 samples from GSE29981. RNA-sequencing, clinical, and survival data on EC were obtained from The Cancer Genome Atlas cohort. Survival analysis revealed that HOXA5 overexpression was associated with poor overall survival in patients with EAEC (p = 0.044, HR = 1.832, 95% CI = 1.006-3.334). Cox regression analysis revealed that HOXA5 was an independent risk factor for poor prognosis in EAEC. The overexpression of HOXA5 was associated with a higher histological grade of EAEC, and it was also associated with TP53 mutation or the high copy number of EC. Our findings suggest the potential of HOXA5 as a novel biomarker for predicting poor survival outcomes in patients with EAEC.

Comprehensive analyses of N6 -methyladenosine-related long noncoding RNA profiles with prognosis, chemotherapy response, and immune landscape in small cell lung cancer

Small cell lung cancer (SCLC) is the most devastating subtype of lung cancer with no clinically available prognostic biomarkers. N⁶ -methyladenosine (m⁶ A) and noncoding RNAs play critical roles in cancer development and treatment response. However, little is known about m⁶ A-related long noncoding RNAs (lncRNAs) in SCLC. We used 206 limited-stage SCLC (LS-SCLC) samples from two cohorts to undertake the first and most comprehensive exploration of the m⁶ A-related lncRNA profile in SCLC and constructed a relevant prognostic signature. In total, 289 m⁶ A-related lncRNAs were screened out. We then built a seven-lncRNA-based signature in the training cohort with 48 RNA sequencing data using univariate and multivariate Cox regression models. The signature was well validated in an independent cohort containing 158 cases with quantitative PCR data. In both cohorts, the signature divided patients into high- and low-risk groups with significantly different survival rates (both p < 0.001). Our signature predicted chemotherapy survival benefit in patients with LS-SCLC. Receiver operating characteristic and C-index analyses indicated that the signature was better at predicting prognosis and chemotherapy benefit than other clinicopathologic features. Moreover, the signature was identified as an independent predictor of prognosis and chemotherapy response in different cohorts. Furthermore, functional analysis showed that multiple activated immune-related pathways were enriched in the low-risk group. Additionally, the signature was also closely related to various immune checkpoints and inflammatory responses. We generated the first clinically available m⁶ A-related lncRNA signature to predict prognosis and chemotherapy benefit in patients with LS-SCLC. Our findings could help optimize the clinical management of patients with LS-SCLC and inform future therapeutic targets for SCLC.

DNMBP-AS1 Regulates NHLRC3 Expression by Sponging miR-93-5p/17-5p to Inhibit Colon Cancer Progression

Long non-coding RNAs (LncRNAs) act as competing endogenous RNAs (ceRNAs) in colon cancer (CC) progression, via binding microRNAs (miRNAs) to regulate the expression of corresponding messenger RNAs (mRNAs). This article aims to explore the detailed molecular mechanism of ceRNA in CC. Top mad 5000 lncRNAs and top mad 5000 mRNAs were used to perform weighted gene co-expression network analysis (WGCNA), and key modules were selected. We used 405 lncRNAs in the red module and 145 mRNAs in the purple module to build the original ceRNA network by online databases. The original ceRNA network included 50 target lncRNAs, 41 target miRNAs, and 34 target mRNAs. Fifty target lncRNAs were used to establish a prognostic risk model by univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses. LncRNAs in the risk model were used to build the secondary ceRNA network, which contained 9 lncRNAs in the risk model, 35 miRNAs, and 29 mRNAs. Survival analyses of 29 mRNAs in the secondary ceRNA network have shown HOXA10 and NHLRC3 were identified as crucial prognostic factors. Finally, we constructed the last ceRNA network including 5 lncRNAs in the risk model, 8 miRNAs, and 2 mRNAs related to prognosis. Quantitative real-time polymerase chain reaction (qRT-PCR) results revealed that DNMBP-AS1 and FAM87A were down-regulated in CC cells and tissues. Function assays showed that over-expression of DNMBP-AS1 and FAM87A inhibited CC cells proliferation and migration. Mechanism study showed that DNMBP-AS1 served as miR-93-5p/17-5p sponges and relieved the suppression effect of miR-93-5p/17-5p on their target NHLRC3. Our study suggested that DNMBP-AS1 inhibited the progression of colon cancer through the miR-93-5p/17-5p/NHLRC3 axis, which could be potential therapeutic targets for CC.

LINC00355 regulates p27KIP expression by binding to MENIN to induce proliferation in late-stage relapse breast cancer

Late-stage relapse (LSR) in patients with breast cancer (BC) occurs more than five years and up to 10 years after initial treatment and has less than 30% 5-year relative survival rate. Long non-coding RNAs (lncRNAs) play important roles in BC yet have not been studied in LSR BC. Here, we identify 1127 lncRNAs differentially expressed in LSR BC via transcriptome sequencing and analysis of 72 early-stage and 24 LSR BC patient tumors. Decreasing expression of the most up-regulated lncRNA, LINC00355, in BC and MCF7 long-term estrogen deprived cell lines decreases cellular invasion and proliferation. Subsequent mechanistic studies show that LINC00355 binds to MENIN and changes occupancy at the CDKN1B promoter to decrease p27Kip. In summary, this is a key study discovering lncRNAs in LSR BC and LINC00355 association with epigenetic regulation and proliferation in BC.

Protein-RNA Interactome Analysis Reveals Wide Association of Kaposi's Sarcoma-Associated Herpesvirus ORF57 with Host Noncoding RNAs and Polysomes

Kaposi's sarcoma-associated herpesvirus (KSHV) ORF57 is an RNA-binding posttranscriptional regulator. We recently applied an affinity-purified anti-ORF57 antibody to conduct ORF57 cross-linking immunoprecipitation (CLIP) in combination with RNA-sequencing (CLIP-seq) and analyzed the genome-wide host RNA transcripts in association with ORF57 in BCBL-1 cells with lytic KSHV infection. Mapping of the CLIP RNA reads to the human genome (GRCh37) revealed that most of the ORF57-associated RNA reads were from rRNAs. The remaining RNA reads mapped to several classes of host noncoding and protein-coding mRNAs. We found that ORF57 binds and regulates expression of a subset of host long noncoding RNAs (lncRNAs), including LINC00324, LINC00355, and LINC00839, which are involved in cell growth. ORF57 binds small nucleolar RNAs (snoRNAs) responsible for 18S and 28S rRNA modifications but does not interact with fibrillarin or NOP58. We validated ORF57 interactions with 67 snoRNAs by ORF57 RNA immunoprecipitation (RIP)-snoRNA array assays. Most of the identified ORF57 rRNA binding sites (BS) overlap the sites binding snoRNAs. We confirmed ORF57-snoRA71B RNA interaction in BCBL-1 cells by ORF57 RIP and Northern blot analyses using a 32P-labeled oligonucleotide probe from the 18S rRNA region complementary to snoRA71B. Using RNA oligonucleotides from the rRNA regions that ORF57 binds for oligonucleotide pulldown-Western blot assays, we selectively verified ORF57 interactions with 5.8S and 18S rRNAs. Polysome profiling revealed that ORF57 associates with both monosomes and polysomes and that its association with polysomes increases PABPC1 binding to polysomes but prevents Ago2 association with polysomes. Our data indicate a functional correlation with ORF57 binding and suppression of Ago2 activities for ORF57 promotion of gene expression. IMPORTANCE As an RNA-binding protein, KSHV ORF57 regulates RNA splicing, stability, and translation and inhibits host innate immunity by blocking the formation of RNA granules in virus-infected cells. In this study, ORF57 was found to interact with many host noncoding RNAs, including lncRNAs, snoRNAs, and rRNAs, to carry out additional unknown functions. ORF57 binds a group of lncRNAs via the RNA motifs identified by ORF57 CLIP-seq to regulate their expression. ORF57 associates with snoRNAs independently of fibrillarin and NOP58 proteins and with rRNA in the regions that commonly bind snoRNAs. Knockdown of fibrillarin expression decreases the expression of snoRNAs and CDK4 but does not affect viral gene expression. More importantly, we found that ORF57 binds translationally active polysomes and enhances PABPC1 but prevents Ago2 association with polysomes. Data provide compelling evidence on how ORF57 in KSHV-infected cells might regulate protein synthesis by blocking Ago2's hostile activities on translation.

In silico interaction of HOX cluster-embedded microRNAs and long non-coding RNAs in oral cancer

The essential role HOX-associated non-coding RNAs play in chromatin dynamics and gene regulation has been well documented. The potential roles of these microRNAs and long non-coding RNAs in oral cancer development, with their attendant involvement in various cellular processes including proliferation, invasion, migration, epithelial-mesenchymal transition and metastasis is gaining credence. An interaction network of HOX-embedded non-coding RNAs was constructed to identify the RNA interaction landscape using the arena-Idb platform and visualized using Cytoscape. The miR-10a was shown to interact with HOXA1, miR-10b with HOXD10, miR-196a1 with HOXA5, HOXA7, HOXB8, HOXC8, HOXD8, and miR-196a2 with HOXA5. The lncRNAs, HOTAIR interacted with HOXC11, HOTAIRM1 with HOXA1 and HOXA4, HOTTIP with HOXA13, HOXA-AS2 with HOXA3, HOXA11-AS with HOXA11 and HOXD-AS1 with HOXB8. Changes in the HOX cluster-embedded non-coding RNAs have implications for prognosis and overall disease survival. Our review aims to analyze the functional significance and clinical relevance of non-coding RNAs within the HOX cluster in the context of oral carcinogenesis. Elucidating these interactions between the non-coding RNAs and HOX genes in oral cancer development and progression could pave the way for the identification of reliable biomarkers and potential therapeutic targets.

Integrative Analysis of Epigenome and Transcriptome Data Reveals Aberrantly Methylated Promoters and Enhancers in Hepatocellular Carcinoma

DNA methylation is a key transcription regulator, whose aberration was ubiquitous and important in most cancers including hepatocellular carcinoma (HCC). Whole-genome bisulfite sequencing (WGBS) was conducted for comparison of DNA methylation in tumor and adjacent tissues from 33 HCC patients, accompanying RNA-seq to determine differentially methylated region-associated, differentially expressed genes (DMR-DEGs), which were independently replicated in the TCGA-LIHC cohort and experimentally validated via 5-aza-2-deoxycytidine (5-azadC) demethylation. A total of 9,867,700 CpG sites showed significantly differential methylation in HCC. Integrations of mRNA-seq, histone ChIP-seq, and WGBS data identified 611 high-confidence DMR-DEGs. Enrichment analysis demonstrated activation of multiple molecular pathways related to cell cycle and DNA repair, accompanying repression of several critical metabolism pathways such as tyrosine and monocarboxylic acid metabolism. In TCGA-LIHC, we replicated about 53% of identified DMR-DEGs and highlighted the prognostic significance of combinations of methylation and expression of nine DMR-DEGs, which were more efficient prognostic biomarkers than considering either type of data alone. Finally, we validated 22/23 (95.7%) DMR-DEGs in 5-azadC-treated LO2 and/or HepG2 cells. In conclusion, integration of epigenome and transcriptome data depicted activation of multiple pivotal cell cycle-related pathways and repression of several metabolic pathways triggered by aberrant DNA methylation of promoters and enhancers in HCC.

Homeobox Genes in Cancers: From Carcinogenesis to Recent Therapeutic Intervention

The homeobox (HOX) genes encoding an evolutionarily highly conserved family of homeodomain-containing transcriptional factors are essential for embryogenesis and tumorigenesis. HOX genes are involved in cell identity determination during early embryonic development and postnatal processes. The deregulation of HOX genes is closely associated with numerous human malignancies, highlighting the indispensable involvement in mortal cancer development. Since most HOX genes behave as oncogenes or tumor suppressors in human cancer, a better comprehension of their upstream regulators and downstream targets contributes to elucidating the function of HOX genes in cancer development. In addition, targeting HOX genes may imply therapeutic potential. Recently, novel therapies such as monoclonal antibodies targeting tyrosine receptor kinases, small molecular chemical inhibitors, and small interfering RNA strategies, are difficult to implement for targeting transcriptional factors on account of the dual function and pleiotropic nature of HOX genes-related molecular networks. This paper summarizes the current state of knowledge on the roles of HOX genes in human cancer and emphasizes the emerging importance of HOX genes as potential therapeutic targets to overcome the limitations of present cancer therapy.

lncRNA LINC00355 Acts as a Novel Biomarker and Promotes Glioma Biological Activities via the Regulation of miR-1225/FNDC3B

Background

Accumulating evidence has implicated long noncoding RNAs (lncRNAs) in glioma progression. Here, we aimed to explore the potential roles of a novel lncRNA, LINC00355, in glioma and to clarify the underlying mechanisms.

Methods

RT-PCR was used to examine the relative expressions of LINC00355 in glioma cell lines and specimen samples. The clinicopathological and prognostic significances of LINC00355 in glioma patients were statistically analyzed. To determine cell activities, CCK-8, clonogenic assays, flow cytometry, migration, and invasion assays were performed. Moreover, the potential mechanisms of LINC00355 were investigated by bioinformatics assays and luciferase reporter assays.

Results

LINC00355 expression was increased in glioma cell lines and specimens, and higher LINC00355 expression predicted advanced clinical progress and reduced overall survival and disease-free survival in glioma patients. Functionally, LINC00355 depletion promoted cell proliferation, invasion, and migration in glioma cells and induced apoptosis of glioma cells, whereas LINC00355 upregulation resulted in the opposite effects in vitro. Mechanistic assays revealed that LINC00355 as a sponge for miR-1225 repressed fibronectin type III domain-containing 3B (FNDC3B) expressions.

Conclusion

Our findings revealed the tumor-promotive roles of LINC00355 in the progression of glioma, indicating that LINC00355 exhibited ceRNA functions via modulating miR-1225/FNDC3B axis.

The ceRNA PVT1 inhibits proliferation of ccRCC cells by sponging miR-328-3p to elevate FAM193B expression

Clear cell renal cell carcinoma (ccRCC) is a common and fatal malignancy. Long noncoding RNAs (lncRNAs) have emerged as crucial biomarkers and regulators in many cancers, warranting the detailed investigation of their biological functions and molecular mechanisms. In this study, we explored the role and mechanism of plasmacytoma variant translocation 1 (PVT1), a competitive endogenous RNA (ceRNA) in ccRCC tissues in vitro and in vivo. We found that PVT1 is upregulated in ccRCC cells and promoted cell proliferation. Bioinformatic analysis, dual-luciferase reporter assays, argonaute 2-RNA immunoprecipitation (AGO2-RIP), quantitative PCR arrays, western blot assay, and rescue experiments were conducted to explore the underlying mechanisms of PVT1. Our analyses revealed that miR-328-3p was a direct target of PVT1 and that FAM193B was a direct target of miR-328-3p. FAM193B is upregulated in ccRCC tissues and promotes cell proliferation by activating the MAPK/ERK and PI3K/AKT pathways. Our results indicated that PVT1 promotes ccRCC cells proliferation by sponging miR-328-3p to upregulate FAM193B and activate the MAPK/ERK and PI3K/AKT pathways. Collectively, these results suggest that PVT1- miR-328-3p-FAM193B loop could serve as a potential biomarker and therapeutic target for ccRCC.

LINC_00355 promotes gastric cancer progression by upregulating PHF19 expression through sponging miR-15a-5p

Background

Long non-coding RNAs exert vital roles in several types of cancer. The objective of this study was to explore the role of LINC_00355 in gastric cancer (GC) progression and its potential mechanism.

Methods

The expression levels of LINC_00355 in GC tissues and cells were detected by quantitative real-time PCR, followed by assessing the effects of LINC_00355 knockdown or overexpression on cell properties. Dual-luciferase reporter assay was utilized to identify the relationship between LINC_00355 and microRNA (miR)-15a-5p and miR-15a-5p and PHD finger protein 19 (PHF19), followed by the rescue experiments.

Results

The results showed that LINC_00355 was highly expressed in GC tissues and cells compared with the corresponding control. LINC_00355 knockdown decreased the viability, migration, and invasion and increased the accumulation of GC cells in G1 phase and apoptosis. Meanwhile, LINC_00355 downregulation markedly increased cleaved caspase 3 and cleaved poly (ADP-ribose) polymerase protein levels, whereas decreased cyclin D1, cyclin E, matrix metalloproteinase (MMP) 9, MMP2, and N-cadherin protein levels in GC cells. However, LINC_00355 overexpression had the opposite effects. It was verified that LINC_00355 upregulated the expression of PHF19 through sponging miR-15a-5p. Furthermore, PHF19 overexpression reversed the effect of LINC_00355 knockdown on GC cell properties, including cell viability, migration, invasion, and apoptosis.

Conclusions

Collectively, these results suggest that LINC_00355 promotes GC progression by up-regulating PHF19 through sponging miR-15a-5p. Our findings may provide an important clinical basis for reversing the malignant phenotype of GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08227-3.

Development of a Machine Learning-Based Autophagy-Related lncRNA Signature to Improve Prognosis Prediction in Osteosarcoma Patients

Background

Osteosarcoma is a frequent bone malignancy in children and young adults. Despite the availability of some prognostic biomarkers, most of them fail to accurately predict prognosis in osteosarcoma patients. In this study, we used bioinformatics tools and machine learning algorithms to establish an autophagy-related long non-coding RNA (lncRNA) signature to predict the prognosis of osteosarcoma patients.

Methods

We obtained expression and clinical data from osteosarcoma patients in the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases. We acquired an autophagy gene list from the Human Autophagy Database (HADb) and identified autophagy-related lncRNAs by co-expression analyses. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the autophagy-related lncRNAs were conducted. Univariate and multivariate Cox regression analyses were performed to assess the prognostic value of the autophagy-related lncRNA signature and validate the relationship between the signature and osteosarcoma patient survival in an independent cohort. We also investigated the relationship between the signature and immune cell infiltration.

Results

We initially identified 69 autophagy-related lncRNAs, 13 of which were significant predictors of overall survival in osteosarcoma patients. Kaplan-Meier analyses revealed that the 13 autophagy-related lncRNAs could stratify patients based on their outcomes. Receiver operating characteristic curve analyses confirmed the superior prognostic value of the lncRNA signature compared to clinically used prognostic biomarkers. Importantly, the autophagy-related lncRNA signature predicted patient prognosis independently of clinicopathological characteristics. Furthermore, we found that the expression levels of the autophagy-related lncRNA signature were significantly associated with the infiltration levels of different immune cell subsets, including T cells, NK cells, and dendritic cells.

Conclusion

The autophagy-related lncRNA signature established here is an independent and robust predictor of osteosarcoma patient survival. Our findings also suggest that the expression of these 13 autophagy-related lncRNAs may promote osteosarcoma progression by regulating immune cell infiltration in the tumor microenvironment.

Exosomal LINC00355 derived from cancer-associated fibroblasts promotes bladder cancer cell proliferation and invasion by regulating miR-15a-5p/HMGA2 axis

We have previously demonstrated that exosomes derived from cancer-associated fibroblasts (CAFs) promote bladder cancer (BC) cell proliferation and invasion by transferring LINC00355. In this study, the molecular mechanisms underlying the pro-bladder cancer action of exosomal LINC00355 were explored. CAFs were obtained from BC tumor tissues, and normal fibroblasts (NFs) were obtained from adjacent normal tissues. Human BC cell lines (T24 and 5367) were incubated with NF-Exo (exosomes from NFs), CAF-Exo (exosomes from CAFs), CAFsi-Ctrl-Exo (exosomes from si-Ctrl-transfected CAFs), and CAFsi-LINC00355-Exo (exosomes from si-LINC00355-transfected CAFs). BC cell proliferation and invasion were evaluated by MTT and Transwell assays, respectively. The interaction between miR-15a-5p and LINC00355 or HMGA2 was examined by online bioinformatics analysis and luciferase activity assay. Results showed that HMGA2 is a direct target of miR-15a-5p, and LINC00355 functions as a sponge of miR-15a-5p to upregulate HMGA2 expression. The promoting effects of CAF-Exo on HMGA2 expression, cell proliferation, and cell invasion were hindered when LINC00355 expression was inhibited in BC cells. These promoting effects were also hindered when miR-15a-5p was overexpressed or HMGA2 was silenced in BC cells. In conclusion, exosomal LINC00355 derived from CAFs promotes BC cell proliferation and invasion by regulating miR-15a-5p/HMGA2 axis.

Exosomal LINC00355 derived from cancer-associated fibroblasts promotes bladder cancer cell resistance to cisplatin by regulating miR-34b-5p/ABCB1 axis

Cisplatin resistance is a major challenge for bladder cancer (BC). Evidence indicates that exosome derived from cancer-associated fibroblasts (CAF-Exo) can promote chemotherapy resistance in various human tumors by delivering bioactive molecules. We have previously demonstrated that CAF-derived exosomal LINC00355 promotes BC cell proliferation and invasion. However, the underlying mechanisms are still unclear. In this study, we aimed to investigate the role and mechanisms of CAF-derived exosomal LINC00355 in BC cell resistance to cisplatin. Exosomes were isolated from normal fibroblasts (NFs) and BC tumor-derived CAFs, namely, NF-Exo and CAF-Exo. CAFs were transfected with si-Ctrl or si-LINC00355 and then different exosomes were isolated, namely, CAFsi-Ctrl-Exo and CAFsi-LINC00355-Exo. The human BC cell lines (T24 and 5367) were incubated with NF-Exo, CAF-Exo, CAFsi-Ctrl-Exo, and CAFsi-LINC00355-Exo in the presence of cisplatin. MTT proliferation assay and flow cytometric analysis showed that CAF-Exo promoted BC cell resistance to cisplatin and upregulated ABCB1 expression in BC cells by transferring LINC00355 to BC cells. Luciferase activity assay confirmed the interaction between miR-34b-5p and LINC00355 or ABCB1. qRT-PCR and western blot analysis further showed that LINC00355 sponged miR-34b-5p to upregulate ABCB1 expression. However, the promoting effects of CAF-Exo on BC cell resistance to cisplatin were abolished by miR-34b-5p overexpression and ABCB1 silencing. In conclusion, exosomal LINC00355 derived from CAFs promotes BC cell resistance to cisplatin by regulating the miR-34b-5p/ABCB1 axis.

Metapristone (RU486-derivative) inhibits endometrial cancer cell progress through regulating miR-492/Klf5/Nrf1 axis

Background

Endometrial cancer is an invasive gynecological cancer prevalent in the world. The pathogenesis of endometrial cancer is related to multiple levels of regulation, referring to oestrogen, tumor-suppressor gene (e.g. PTEN) or microRNAs (e.g. miR-23a and miR-29b). Metapristone is a hormone-related drug, which is widely used in clinical treatment of endometrial cancer. However, the underlying regulatory mechanism of metapristone on endometrial cancer is still unclear, especially the regulatory effect on microRNAs. The aim of this study is to investigate the specific molecular mechanism of metapristone regulating microRNAs in the treatment of endometrial cancer.

Methods

RL95-2 cells and Ishikawa cells were used as the endometrial cancer models. MiR-492 or si-miR-492 was transfected into RL95-2 cells and Ishikawa cells to explore the role of miR-492 in endometrial cancer. The cell cancer model and mice cancer model were used to confirm the function and mechanism of metapristone affected on endometrial cancer in vitro and in vivo. Mechanically, cell proliferation was monitored using MTT assay, cell colony formation assay and EdU assay. Luciferase reporter assay was used to identify the downstream target gene of miR-492. The protein expression and RNA expression were respectively measured by western blot and qRT-PCR for cell signaling pathway research, subsequently, were verified in the mice tumor model via immunohistochemistry.

Results

Metapristone as a kind of hormone-related drug significantly inhibited the endometrial cancer cell growth through regulating cell apoptosis-related gene expression. Mechanically, miR-492 and its target genes Klf5 and Nrf1 were highly expressed in the endometrial cancer cell lines, which promoted cell proliferation and inhibited cell apoptosis. Metapristone decreased the expression of miR-492 and its target genes Klf5 and Nrf1, leading to endometrial cancer cell growth inhibition in vitro and in vivo.

Conclusion

Metapristone inhibited the endometrial cancer cell growth through regulating the cell apoptosis-related signaling pathway and decreasing the expression of miR-492 and its downstream target genes (Klf5 and Nrf1), which provided the theoretical basis in clinical treatment of endometrial cancer.

Long Non-Coding RNA LINC00355 Promotes the Development and Progression of Colorectal Cancer by Elevating Guanine Nucleotide Exchange Factor T Expression via RNA Binding Protein lin-28 Homolog A

Background

Our previous study showed that guanine nucleotide exchange factor T (GEFT) was highly expressed in colorectal cancer (CRC) tissues and CRC patients with high GEFT expression had a poor prognosis, and suggested the close link of GEFT expression and CRC tumorigenesis/metastasis. In this text, the roles and upstream regulatory mechanisms of GEFT in the development and progression of CRC were further investigated.

Methods

Expression levels of GEFT mRNA and LINC00355 was measured by RT-qPCR assay. Protein levels of lin-28 homologue A (LIN28A) and GEFT were determined by western blot assay. Cell proliferative, migratory, and invasive capacities were assessed by CCK-8, Transwell migration and invasion assays, respectively. The effect of GEFT knockdown on CRC tumorigenesis was examined by mouse xenograft experiments in vivo. GEFT mRNA stability was examined by actinomycin D assay. The relationships of LINC000355, LIN28A, and GEFT were explored by RNA pull down and RIP assays.

Results

GEFT was highly expressed in CRC tissues and cell lines. GEFT knockdown inhibited CRC cell proliferation, migration, and invasion, and hindered CRC xenograft tumor growth. GEFT overexpression alleviated the detrimental effects of LINC00355 loss on CRC cell proliferation, migration, and invasion. LINC00355 promoted GEFT expression and enhanced GEFT mRNA stability via LIN28A. LIN28A knockdown weakened the promotive effect of LINC00355 on CRC cell proliferation, migration, and invasion.

Conclusion

LINC00355 facilitated CRC tumorigenesis and progression by increasing GEFT expression via LIN28A, deepening our understanding on roles and upstream regulatory mechanisms of GEFT in CRC development and progression.

LINC00355 promoted the progression of lung squamous cell carcinoma through regulating the miR-466/LYAR axis

LINC00355 has been reported aberrantly over-expressed and associated with poor prognosis in various types of cancer. However, reports regarding the effect of LINC00355 on lung squamous cell carcinoma (SCC) are rare. This study aimed to explore the function of LINC00355 in the development and progression of lung SCC and reveal the underlying mechanism. The expression and subcellular location of LINC00355 were determined by qRT-PCR and RNA-FISH, respectively. The lung SCC cell growth was analyzed by CCK-8 assay, transwell invasion, wound healing, colony formation, and flow cytometry assays. Reactive oxygen species level was evaluated by DCFH-DA probes. Bioinformatics online websites, luciferase reporter assay, RNA binding protein immunoprecipitation (RIP), and RNA pull-down assays were utilized to investigate the interaction among LINC00355, miR-466, and Ly-1 antibody reactive clone (LYAR). The results showed that LINC00355 was upregulated in lung SCC and was positively associated with poor overall survival in lung SCC patients. LINC00355 was mainly located in the cytoplasm of SCC cells. Additionally, LINC0035 functioned as a competing endogenous RNA (ceRNA) to target miR-466, and LYAR was identified as a direct target of miR-466. LINC00355 expression negatively correlated with miR-466 level, and positively correlated with LYAR level. Mechanistically, knockdown of LINC00355 inhibited cell proliferation, migration and invasion, promoted cell apoptosis in vitro, and suppressed tumor growth in vivo through targeting miR-466, and thus down-regulated LYAR expression. These findings provide a new sight for understanding the molecular mechanism of lung SCC and indicate that LINC00355 may serve as a potential biomarker for the diagnosis and treatment of lung SCC.

MiRNA-128 and MiRNA-142 Regulate Tumorigenesis and EMT in Oral Squamous Cell Carcinoma Through HOXA10

Background

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of all oral cavity cancers, and the 5-year survival rate for OSCC patients remains unsatisfactory. MiRNA-128/miRNA-142 has been reported to work as a tumor suppressor in diverse tumors. However, the biological function of miR-128/miR-142 in OSCC is still unknown.

Methods

The expression of miR-128/miR-142 and homeobox A10 (HOXA10) in OSCC tissues and cells was measured by quantitative real-time polymerase chain reaction (RT-qPCR). The effects of miR-128/miR-142 or HOXA10 on proliferation, migration, invasion and apoptosis were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), transwell and flow cytometry assays, respectively. The expression levels of epithelial–mesenchymal transition (EMT)-associated proteins (E-cadherin, N-cadherin and Vimentin), proliferation-associated protein ki-67 and HOXA10 were detected by Western blot assay. The interaction between HOXA10 and miR-128/miR-142 was predicted by TargetScan, and then confirmed by dual-luciferase reporter assay.

Results

MiR-128/miR-142 was downregulated in OSCC tissues and cells. Overexpression of miR-128/miR-142 inhibited proliferation, migration, invasion and EMT and induced apoptosis in OSCC cells. HOXA10 as the target of miR-128/miR-142 was verified in OSCC cells. Knockdown of HOXA10 also repressed proliferation, migration, invasion and EMT and boosted apoptosis in OSCC cells. Upregulation of miR-128/miR-142 hindered the expression level of HOXA10, while introduction of HOXA10 weakened the effect.

Conclusion

MiR-128/miR-142 suppressed OSCC tumorigenesis and metastasis by targeting HOXA10, providing a new promising therapeutic approach for OSCC patient diagnosis and treatment.

LINC00355 induces gastric cancer proliferation and invasion through promoting ubiquitination of P53

Long noncoding RNAs (LncRNAs) have been reported to play critical roles in gastric cancer, but true biomarkers remain unknown. In this study, we found a new lncRNA LINC00355 that was involved in malignant progression of gastric cancer (GC) and further revealed its role and mechanism. Differentially expressed lncRNAs were identified through bioinformatics, and qRT-PCR was used to validate the expression of LINC00355 in gastric cancer tissues and cells. The biological role of LINC00355 in GC was detected by gene overexpression and knockdown experiments. Subcellular fractionation, qRT-PCR, and FISH were performed to detect the subcellular localization. Co-IP and western blotting were used to study the ubiquitination-mediated regulation of P53 and the expression of the E3 ligases RAD18 and UBE3C. The results showed that LINC00355 was significantly increased in gastric cancer cell lines and patient tissues and closely correlated with late stages, distant metastasis, and poor prognosis of patients. High expression of LINC00355 promoted the proliferation and invasion of gastric cancer cells in vivo and in vitro. Mechanistic studies found that LINC00355 that mainly located in the nucleus, acting as a transcriptional activator, promoted transcription of RAD18 and UBE3C, which both bind to P53 and mediate the ubiquitination and degradation of P53. Furthermore, LINC00355 overexpression enhanced the ubiquitination process, and LINC00355 knockdown alleviated it. These results indicated that LINC00355 induces gastric cancer cell proliferation and invasion by promoting transcription of RAD18 and UBE3C, which mediates ubiquitination of P53 and thereby plays a critical role in survival and tumorigenicity of gastric cancer cells. LINC00355 may represent a new mechanism for GC progression and provide a potential marker for GC diagnosis and treatment.

Long Noncoding RNA SNHG12 Indicates the Prognosis and Accelerates Tumorigenesis of Diffuse Large B-Cell Lymphoma Through Sponging microR-195

Background

Small nucleolar RNA host gene 12 (SNHG12) expression is associated with multiple cancers, including renal cell carcinoma, prostate cancer, cervical cancer, nasopharyngeal carcinoma, colorectal cancer, and hepatocellular carcinoma. However, SNHG12 biological function is unclear in diffuse large B-cell lymphoma (DLBCL).

Methods

SNHG12 expression and associated clinicopathological characteristics were evaluated in DLBCL tissues. CCK-8 and transwell assay were used to analyze the in vitro role of SNHG12 in DLBCL progression. The xenograft model was used to explore the in vivo role of SNHG12 in DLBCL growth. The physical interaction between SNHG12 and miR-195 was confirmed using bioinformatics analysis and a dual luciferase assay.

Results

SNHG12 expression was upregulated in DLBCL tissues and correlated with patients’ prognosis. SNHG12 downregulation inhibited cell growth, migration, and invasion of DLBCL cells in vitro, while its overexpression promoted these cellular processes. Moreover, SNHG12 knockdown repressed tumorigenesis of DLBCL cells in vivo. Further experiments demonstrated that miR-195 is a target of SNHG12 in DLBCL and that their expression negatively correlates in DLBCL. SNHG12 functioned as a competing endogenous RNA for miR-195 in DLBCL cells and miR-195 upregulation abolished the effects of SNHG12 on of DLBCL progression.

Conclusion

SNHG12 predicts poor clinical outcome and serves as a novel oncogene in DLBCL via miR-195 sponging. We also suggest that SNHG12 can be used as a potential therapeutic candidate for DLBCL patients.

lncRNA LIFR-AS1 suppresses invasion and metastasis of non-small cell lung cancer via the miR-942-5p/ZNF471 axis

Background

MicroRNA 942-5p (miR-942-5p) has been reported to promote migration and invasion in non-small cell lung cancer (NSCLC), but the underlying mechanism is not completely understood. The interplay between long non-coding RNAs (lncRNAs) and miRNAs plays a crucial role in tumor progression.

Methods

In the present study, we performed bioinformatic and biochemical analyses to identify miR-942-5p-interacting lncRNAs. The function and clinical significance of the candidate lncRNA(s) in NSCLC were determined.

Results

We identified LIFR-AS1 as a pivotal miR-942-5p-interacting lncRNA. Overexpression of miR-942-5p caused a reduction of LIFR-AS1 in NSCLC cells. LIFR-AS1 showed the ability to sponge miR-942-5p, leading to derepression of ZNF471. Functionally, LIFR-AS1 overexpression inhibited NSCLC cell migration and invasion, whereas LIFR-AS1 silencing yielded an opposite effect. In vivo studies confirmed that LIFR-AS1 overexpression suppressed lung metastasis of NSCLC cells. Rescue experiments demonstrated that enforced expression of miR-942-5p or depletion of ZNF471 restored the migration and invasion capacity of LIFR-AS1-overexpressing cells. Moreover, overexpression of ZNF471 restrained NSCLC cell invasion. Clinically, LIFR-AS1 downregulation was significantly correlated with TNM stage, lymph node metastasis, and reduced overall survival in NSCLC patients.

Conclusions

we provide first evidence for the involvement of the LIFR-AS1/miR-942-5p/ZNF471 axis in NSCLC invasion and metastasis. LIFR-AS1 may represent a novel target for the treatment of NSCLC.