Emerging roles of noncoding RNAs in human cancers

Hsa_circYARS interacts with miR-29a-3p to up-regulate IREB2 and promote laryngeal squamous cell carcinoma progression

OBJECTIVE

This study was to investigate the carcinogenic capacity of circYARS in laryngeal squamous cell carcinoma (LSCC) and to reveal its potential mechanism as a competitive endogenous RNA.

METHODS

The differentially expressed circRNA and mRNA in LSCC were detected by RT-qPCR. Dual luciferase reporter assay and RIP were conducted to test the interaction between circYARS, miR-29a-3p, and IREB2. The functional effects of these molecules were investigated by CCK-8, flow cytometry, colony formation assay, Transwell, Western blot, and xenotransplantation mouse models.

RESULTS

In LSCC tissues and cell lines, circYARS and IREB2 levels were enhanced, while miR-29a-3p level was lowered. Depleting circYARS led to decreased IREB2 by promoting miR-29a-3p expression. As a result of miR-29a-3p enhancement or circYARS silence, the proliferative, migratory, and invasion of cancer cells were suppressed and apoptosis was stimulated.

CONCLUSION

circYARS is involved in the tumorigenicity and progression of LSCC through the miR-29a-3p/IREB2 axis, providing strategies and targets for therapeutic intervention of LSCC.

Regulatory role of lncH19 in RAC1 alternative splicing: implication for RAC1B expression in colorectal cancer

Aberrant alternative splicing events play a critical role in cancer biology, contributing to tumor invasion, metastasis, epithelial-mesenchymal transition, and drug resistance. Recent studies have shown that alternative splicing is a key feature for transcriptomic variations in colorectal cancer, which ranks third among malignant tumors worldwide in both incidence and mortality. Long non-coding RNAs can modulate this process by acting as trans-regulatory agents, recruiting splicing factors, or driving them to specific targeted genes. LncH19 is a lncRNA dis-regulated in several tumor types and, in colorectal cancer, it plays a critical role in tumor onset, progression, and metastasis. In this paper, we found, that in colorectal cancer cells, the long non-coding RNA H19 can bind immature RNAs and splicing factors as hnRNPM and RBFOX2. Through bioinformatic analysis, we identified 57 transcripts associated with lncH19 and containing binding sites for both splicing factors, hnRNPM, and RBFOX2. Among these transcripts, we identified the mRNA of the GTPase-RAC1, whose alternatively spliced isoform, RAC1B, has been ascribed several roles in the malignant transformation. We confirmed, in vitro, the binding of the splicing factors to both the transcripts RAC1 and lncH19. Loss and gain of expression experiments in two colorectal cancer cell lines (SW620 and HCT116) demonstrated that lncH19 is required for RAC1B expression and, through RAC1B, it induces c-Myc and Cyclin-D increase. In vivo, investigation from biopsies of colorectal cancer patients showed higher levels of all the explored genes (lncH19, RAC1B, c-Myc and Cyclin-D) concerning the healthy counterpart, thus supporting our in vitro model. In addition, we identified a positive correlation between lncH19 and RAC1B in colorectal cancer patients. Finally, we demonstrated that lncH19, as a shuttle, drives the splicing factors RBFOX2 and hnRNPM to RAC1 allowing exon retention and RAC1B expression. The data shown in this paper represent the first evidence of a new mechanism of action by which lncH19 carries out its functions as an oncogene by prompting colorectal cancer through the modulation of alternative splicing.

The roles of lncRNA AP001469.3 in clinical implications, immune landscape and carcinogenesis of colorectal cancer

Background

Previously, long non-coding RNA (lncRNA) gene AP001469.3 was reported to participate in the construction of an immune-related lncRNA signature, which showed promising clinical predictive value in colorectal cancer (CRC) patients. However, the clinical and immunological significance and biological function of AP001469.3 in CRC remain unclear. In this study, we aim to explore the roles of AP001469.3 in CRC progression, thereby opening an avenue for CRC treatment.

Methods

Our study collected data from The Cancer Genome Atlas (TCGA) database and investigated the role of AP001469.3 in CRC through bioinformatics analysis. Cell-type Identification By Estimating Relative Subsets Of known RNA Transcripts (CIBERSORT) and Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) methods evaluated the immune infiltration. The biological functions of AP001469.3 in CRC were validated by in vitro experiments. Gene set enrichment analysis (GSEA) was used to estimate the enrichment of functional pathways and gene signatures.

Results

In this work, high expression of AP001469.3 was found in CRC and was positively associated with tumor-node-metastasis (TNM) stage in CRC. AP001469.3 expression had a strong relationship with microsatellite instability (MSI) in colon adenocarcinoma (COAD). Additionally, AP001469.3 expression was associated with StromalScore, ImmuneScore, ESTIMATEScore, immune cell infiltration (ICI) levels and immune checkpoint (ICP) genes expression in CRC. Subsequent results showed that immunotherapy could be more effective in CRC patients with low-AP001469.3 expression using the immunophenoscore (IPS). We confirmed that the transcript of AP001469.3 gene ENST00000430259 was highly expressed in CRC tissues and cell lines. In vitro experiments indicated that ENST00000430259 knockdown reduced the proliferation, migration and invasion of CRC cells. Finally, our GSEA results showed that the majority of the differentially enriched signaling pathways between the high- and low-AP001469.3 expression groups were immune-related.

Conclusions

Taken together, our study demonstrates that lncRNA gene AP001469.3 is associated with immunological characteristics in CRC and promotes malignant progression of CRC. Moreover, AP001469.3 can be potentially used as an immunotherapeutic indicator and a therapeutic target for CRC patients.

Decoding the Non-coding: Tools and Databases Unveiling the Hidden World of "Junk" RNAs for Innovative Therapeutic Exploration

Non-coding RNAs are pivotal regulators of gene and protein expression, exerting crucial influences on diverse biological processes. Their dysregulation is frequently implicated in the onset and progression of diseases, notably cancer. A profound comprehension of the intricate mechanisms governing ncRNAs is imperative for devising innovative therapeutic interventions against these debilitating conditions. Significantly, nearly 80% of our genome comprises ncRNAs, underscoring their centrality in cellular processes. The elucidation of ncRNA functions is pivotal for grasping the complexities of gene regulation and its implications for human health. Modern genome sequencing techniques yield vast datasets, stored in specialized databases. To harness this wealth of information and to understand the crosstalk of non-coding RNAs, knowledge of available databases is required, and many new sophisticated computational tools have emerged. These tools play a pivotal role in the identification, prediction, and annotation of ncRNAs, thereby facilitating their experimental validation. This Review succinctly outlines the current understanding of ncRNAs, emphasizing their involvement in disease development. It also highlights the databases and tools instrumental in classifying, annotating, and evaluating ncRNAs. By extracting meaningful biological insights from seemingly "junk" data, these tools empower scientists to unravel the intricate roles of ncRNAs in shaping human health.

circ_0006789 promotes cervical cancer development via the miR-615-5p/HSF1 axis

OBJECTIVE

Circular RNAs (circRNAs) are involved in the development of human cancers, including cervical cancer (CC). However, the role and mechanism of circ_0006789 (circSLC25A43) in CC are unclear. The purpose of this study was to investigate the functional role of circ_0006789 in CC.

METHODS

The expression of circ_0006789 in CC tissues and cell lines was examined by RT-qPCR. The characterization of circ_0006789 in CC cells was verified by subcellular localisation, actinomycin D assay, and RNase R assay. After circ_0006789 was knocked down in CC cell lines, the proliferation, apoptosis, migration and invasion of CC cells were assessed by CCK-8 method, flow cytometry, and Transwell assay. RIP assay, FISH assay, dual luciferase reporter gene assay and Western blot were used to investigate the regulatory mechanism between circ_0006789, miR-615-5p and heat shock factor 1 (HSF1).

RESULTS

circ_0006789 was upregulated in CC tissues and cell lines. CC cells were inhibited in their proliferation, migration, and invasion, as well as promoted to apoptosis when circ_0006789 was knocked down. It was found that circ_0006789 targeted miR-615-5p, and miR-615-5p expression was inversely correlated with circ_0006789 expression. Furthermore, HSF1 was a target gene of miR-615-5p. Furthermore, the suppressive effects on HeLa cells mediated by circ_0006789 knockdown were counter-balanced when miR-615-5p was knocked down and HSF1 was overexpressed. Mechanistically, circ_0006789 was found to promote CC development by reducing miR-615-5p and increasing HSF1 expressions.

CONCLUSION

circ_0006789 accelerates CC development via the miR-615-5p/HSF1 axis.

Research progress and applications of epigenetic biomarkers in cancer

Epigenetic changes are heritable changes in gene expression without changes in the nucleotide sequence of genes. Epigenetic changes play an important role in the development of cancer and in the process of malignancy metastasis. Previous studies have shown that abnormal epigenetic changes can be used as biomarkers for disease status and disease prediction. The reversibility and controllability of epigenetic modification changes also provide new strategies for early disease prevention and treatment. In addition, corresponding drug development has also reached the clinical stage. In this paper, we will discuss the recent progress and application status of tumor epigenetic biomarkers from three perspectives: DNA methylation, non-coding RNA, and histone modification, in order to provide new opportunities for additional tumor research and applications.

Role of the circular RNA regulatory network in the pathogenesis of biliary atresia

Circular RNAs (circRNAs) serve an essential role in the occurrence and development of cholangiocarcinoma, but the expression and function of circRNA in biliary atresia (BA) is not clear. In the present study, circRNA expression profiles were investigated in the liver tissues of patients with BA as well as in the choledochal cyst (CC) tissues of control patients using RNA sequencing. A total of 78 differentially expressed circRNAs (DECs) were identified between the BA and CC tissues. The expression levels of eight circRNAs (hsa_circ_0006137, hsa_circ_0079422, hsa_circ_0007375, hsa_circ_0005597, hsa_circ_0006961, hsa_circ_0081171, hsa_circ_0084665 and hsa_circ_0075828) in the liver tissues of the BA group and control group were measured using reverse transcription-quantitative polymerase chain reaction. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis demonstrated that the identified DECs are involved in a variety of biological processes, including apoptosis and metabolism. In addition, based on the GO and KEGG pathway enrichment analyses, it was revealed that target genes that can be affected by circRNAs regulatory network were enriched in the TGF-β signaling pathway, EGFR tyrosine kinase inhibitor resistance pathway and transcription factor regulation pathway as well as other pathways that may be associated with the pathogenesis of BA. The present study revealed that circRNAs are potentially implicated in the pathogenesis of BA and could help to find promising targets and biomarkers for BA.

Circular RNAs in breast cancer diagnosis, treatment and prognosis

Breast cancer has surpassed lung cancer to become the most common malignancy worldwide. The incidence rate and mortality rate of breast cancer continue to rise, which leads to a great burden on public health. Circular RNAs (circRNAs), a new class of noncoding RNAs (ncRNAs), have been recognized as important oncogenes or suppressors in regulating cancer initiation and progression. In breast cancer, circRNAs have significant roles in tumorigenesis, recurrence and multidrug resistance that are mediated by various mechanisms. Therefore, circRNAs may serve as promising targets of therapeutic strategies for breast cancer management. This study reviews the most recent studies about the biosynthesis and characteristics of circRNAs in diagnosis, treatment and prognosis evaluation, as well as the value of circRNAs in clinical applications as biomarkers or therapeutic targets in breast cancer. Understanding the mechanisms by which circRNAs function could help transform basic research into clinical applications and facilitate the development of novel circRNA-based therapeutic strategies for breast cancer treatment.