Upregulated Long Noncoding RNA LINC01234 Predicts Unfavorable Prognosis for Colorectal Cancer and Negatively Correlates With KLF6 Expression

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Tumor cell-derived exosomes mediating hsa_circ_0001739/lncRNA AC159540.1 facilitate liver metastasis in colorectal cancer

BACKGROUND

The current study probed into how tumor cell-derived exosomes (Exos) mediated hsa_circ_0001739/lncRNA AC159540.1 to manipulate microRNA (miR)-218-5p/FTO-N6-methyladenosine (m6A)/MYC signal axis in liver metastasis in colorectal cancer (CRC).

METHODS

hsa_circ_0001739 and lncRNA AC159540.1 were identified as the upstream regulator of miR-218-5p using ENCORI and LncBase databases. Expression patterns of miR-218-5p, hsa_circ_0001739, lncRNA AC159540.1, FTO, and MYC were detected, accompanied by loss-and-gain-of function assays to examine their effects on CRC cell biological functions. SW480 cells-derived Exos were purified, followed by in vitro studies to uncover the effect of hsa_circ_0001739/lncRNA AC159540.

RESULTS

miR-218-5p was downregulated while hsa_circ_0001739/lncRNA AC159540.1 was upregulated in CRC tissues and cells. Silencing of hsa_circ_0001739/lncRNA AC159540.1 restrained the malignant phenotypes of CRC cells. Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 competitively inhibited miR-218-5p to elevate FTO and MYC. The inducing role of Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 in CRC was also validated in vivo.

CONCLUSION

Conclusively, Exos-mediated circ_0001739/lncRNA AC159540.1 regulatory network is critical for CRC, offering a theoretical basis for CRC treatment.

Krüppel-like factors in tumors: Key regulators and therapeutic avenues

Krüppel-like factors (KLFs) are a group of DNA-binding transcriptional regulators with multiple essential functions in various cellular processes, including proliferation, migration, inflammation, and angiogenesis. The aberrant expression of KLFs is often found in tumor tissues and is essential for tumor development. At the molecular level, KLFs regulate multiple signaling pathways and mediate crosstalk among them. Some KLFs may also be molecular switches for specific biological signals, driving their transition from tumor suppressors to promoters. At the histological level, the abnormal expression of KLFs is closely associated with tumor cell stemness, proliferation, apoptosis, and alterations in the tumor microenvironment. Notably, the role of each KLF in tumors varies according to tumor type and different stages of tumor development rather than being invariant. In this review, we focus on the advances in the molecular biology of KLFs, particularly the regulations of several classical signaling pathways by these factors, and the critical role of KLFs in tumor development. We also highlight their strong potential as molecular targets in tumor therapy and suggest potential directions for clinical translational research.

Oncogenic roles of LINC01234 in various forms of human cancer

Abnormal expression of long non-coding RNAs (lncRNAs) plays an essential role in various malignant neoplasia. As a newly identified lncRNA, LINC01234 is abnormally expressed in several types of cancers and promotes the development of cancers. Accumulating evidence indicates that overexpression of LINC01234 is associated with poor clinical outcomes. Moreover, LINC01234 modulates many cellular events as a putative proto-oncogene, including proliferation, migration, invasion, apoptosis, cell cycle progression, and EMT. In terms of molecular mechanism, LINC01234 regulates gene expression by acting as ceRNA, participating in signaling pathways, interacting with proteins and other molecules, and encoding polypeptide. It reveals that LINC01234 may serve as a potential biomarker for cancer diagnosis, treatment, and prognosis. This review summarizes the expression pattern, biological function, and molecular mechanism of LINC01234 in human cancer and discusses its potential clinical utility.

N6-methyladenosine-related lncRNAs is a potential marker for predicting prognosis and immunotherapy in ovarian cancer

Background

With a lack of specific symptoms, ovarian cancer (OV) is often diagnosed at an advanced stage. This coupled with inadequate prognostic indicators and treatments with limited therapeutic effect make OV the deadliest type of gynecological tumor. Recent research indicates that N6-methyladenosine (m6A) and long-chain non-coding RNA (lncRNA) play important roles in the prognosis of OV and the efficacy of immunotherapy.

Results

Using the Cancer Genome Atlas (TCGA) OV-related data set and the expression profiles of 21 m6A-related genes, we identified two m6A subtypes, and the differentially expressed genes between the two. Based on the differentially expressed lncRNAs in the two m6A subtypes and the lncRNAs co-expressed with the 21 m6A-related genes, single-factor cox and LASSO regression were used to further isolate the 13 major lncRNAs. Finally, multi-factor cox regression was used to construct a m6A-related lncRNA risk score model for OV, with good performance in patient prognosis. Using risk score, OV tumor samples are divided into with high- and low-score groups. We explored the differences in clinical characteristics, tumor mutational burden, and tumor immune cell infiltration between the two groups, and evaluated the risk score’s ability to predict the benefit of immunotherapy.

Conclusion

Our m6A-based lncRNA risk model could be used to predict the prognosis and immunotherapy response of future OV patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-022-00222-3.

Long Non-coding RNA TPT1-AS1 Suppresses APC Transcription in a STAT1-Dependent Manner to Increase the Stemness of Colorectal Cancer Stem Cells

Cancer stem cells (CSCs) are the major culprits leading to a new level of complexity and the consequential therapy resistance and disease recurrence in colorectal cancer (CRC). This study focuses on the effect of long non-coding RNA (lncRNA) TPT1-AS1 and its associated molecules on the stemness maintenance of CRC stem cells. TPT1-AS1 was identified as a significantly upregulated gene in CRC using the GSE146587 dataset. Stem cells from CRC HCT116 and CACO2 cells were isolated. TPT1-AS1 was significantly highly expressed in the CSCs compared to non-stem cells. Downregulation of TPT1-AS1 reduced the stemness of the CRC stem cells. TPT1-AS1 recruited STAT1 to the promoter region of APC to suppress APC transcription. Further upregulation of STAT1 or downregulation of APC blocked the role of TPT1-AS1 silencing and restored the malignant behaviors of CSC stem cells. APC inactivated the Wnt/β-catenin pathway. Overexpression of STAT1 restored the levels of cyclin D1 and β-catenin in cells suppressed by TPT1-AS1 silencing. In summary, this work demonstrates that TPT1-AS1 recruits STAT1 to suppress APC transcription and increase the stemness of colorectal CSCs via Wnt/β-catenin activation.

Effects of laparoscopic radical surgery in the treatment of colorectal cancer and correlations of VEGF and TGF-β1 with prognosis

OBJECTIVE

To investigate the effects of laparoscopic radical surgery on the treatment of colorectal cancer (CRC) and explore the correlations of vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) with prognosis.

METHODS

The clinical data of 210 patients with CRC admitted to the Yantai Zhifu Hospital from February 2015 to February 2018 were analyzed retrospectively. Among them, 110 patients were treated with laparoscopic radical surgery and assigned to the observation group, and the rest 100 patients were treated with routine open surgery and included in the open group. The two groups were compared in terms of operation time (OT), intraoperative blood loss (IBL), postoperative exhaust time (PET), length of hospital stays (LOS) and incidence of complications. Patients were also followed up for 3 years to count their survival rates. Serum expression levels of VEGF and TGF-β1, detected by enzyme-linked immunosorbent assays (ELISAs), were compared before and after treatment, and their correlations with patients' clinicopathological data and prognosis were analyzed.

RESULTS

Compared with the open group, patients in the observation group had longer OT, but lower IBL, PET, LOS, and overall incidence of complications. In the observation group, VEGF and TGF-β1 expression after treatment was remarkably lower than that before treatment and that in the open group. A 3-year survival rate of 80.0% was observed in the observation group. Univariate analysis showed that serum VEGF and TGF-β1 expression levels were closely related to Dukes staging and lymph node metastasis (LNM) (P<0.05). The Log-Rank test showed that the survival rate of patients with high VEGF and TGF-β1 expression was remarkably lower than that of those with low expression (P<0.05). According to Cox model multivariate analysis, Dukes staging, LNM, surgical methods and high VEGF and TGF-β1 expression were all independent risk factors for the prognosis of CRC patients (P<0.05).

CONCLUSION

Laparoscopic radical surgery is effective and safe in treating CRC. VEGF and TGF-β1 are highly expressed in the serum of CRC patients, and are closely related to the tumor staging, LNM and prognosis of patients, which are of great significance for evaluating the condition and prognosis of CRC patients.

miR‑4306 inhibits the malignant behaviors of colorectal cancer by regulating lncRNA FoxD2‑AS1

MicroRNA (miR)‑4306 and FoxD2‑adjacent opposite strand RNA 1 (FOXD2‑AS1) are cancer‑related genes involved in tumor progression. However, the potential functional roles of miR‑4306 and FoxD2‑AS1 in colorectal cancer (CRC) development remain unknown. The present study aimed to investigate the biological functions and the molecular mechanisms of miR‑4306 and FoxD2‑AS1 in CRC. Reverse transcription‑quantitative PCR analysis was performed to determine the expression levels of FoxD2‑AS1 and miR‑4306 in CRC tissues and cell lines. Functional experiments, including Cell Counting Kit‑8, colony formation, cell cycle assays and western blotting, were conducted to examine the effects of FoxD2‑AS1 and miR‑4306 on the malignant behaviors of CRC cells. In addition, the relationship between FoxD2‑AS1 and miR‑4306 was assessed using a dual‑luciferase reporter assay and Pearson's correlation analysis. Compared with normal samples and cells, FoxD2‑AS1 expression was increased and miR‑4306 expression was decreased in CRC tissues and cells. Functional experiments demonstrated that silencing FoxD2‑AS1 inhibited proliferation and induced cell arrest at G0/G1 phase in CRC cells, while the overexpression of FoxD2‑AS1 showed opposite results. Ki‑67 and proliferating cell nuclear antigen expression levels were decreased after transfection with small interfering RNA FoxD2‑AS1, but were increased after transfection with FoxD2‑AS1 overexpression plasmid. Furthermore, investigations into the underling mechanism revealed that FoxD2‑AS1 functioned as a molecular sponge of miR‑4306. The inhibitory effects of FoxD2‑AS1 silencing on CRC progression were reversed by miR‑4306 knockdown. Collectively, the present study demonstrated that FoxD2‑AS1 functioned as an oncogene in CRC progression, and that miR‑4306 could inhibit the malignant behaviors of CRC by regulating FoxD2‑AS1. Thus, the current study provided a promising therapeutic target for CRC treatment.

LINC01234 aggravates cell growth and migration of triple-negative breast cancer by activating the Wnt pathway

Triple-negative breast cancer (TNBC) is a common cancer with increasing incidence and mortality in female. Increasing studies have revealed that long noncoding RNAs (lncRNAs) are novel molecules regulating tumors. Long intergenic non-protein coding RNA 1234 (LINC01234) has been demonstrated to function as an oncogene in several tumors. However, the role of LINC01234 in TNBC remains unelucidated. Herein, RT-qPCR showed that LINC01234 expression was upregulated in both TNBC tissues and cell lines. Functionally, knockdown of LINC01234 suppressed proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) process, and promoted apoptosis in TNBC cells. Xenograft mouse models revealed that LINC01234 downregulation inhibited TNBC tumor growth in vivo. Furthermore, LINC01234 was transcriptionally elevated by Sp1 transcription factor (SP1) in TNBC cells. Mechanistically, LINC01234 interacted with miR-525-5p and miR-525-5p targeted MEIS2. Rescue assays manifested that MEIS2 overexpression rescued the cellular processes inhibited by silenced LINC01234. Moreover, we validated that LINC01234 regulated the activation of the Wnt pathway through modulating MEIS2 in TNBC cells. In conclusion, LINC01234 aggravated TNBC cell growth, migration, invasion and EMT by modulating the miR-525-5p/MEIS2 axis and activating the Wnt/β-catenin signaling pathway.

The Emerging Landscape of Long Non-Coding RNAs in Colorectal Cancer Metastasis

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers, with extremely high rates of morbidity and mortality. The main cause of death in CRC is distant metastasis; it affects patient prognosis and survival and is one of the key challenges in the treatment of CRC. Long non-coding RNAs (lncRNAs) are a group of non-coding RNA molecules with more than 200 nucleotides. Abnormal lncRNA expression is closely related to the occurrence and progression of several diseases, including cancer. Recent studies have shown that numerous lncRNAs play pivotal roles in the CRC metastasis, and reversing the expression of these lncRNAs through artificial means can reduce the malignant phenotype of metastatic CRC to some extent. This review summarizes the major mechanisms of lncRNAs in CRC metastasis and proposes lncRNAs as potential therapeutic targets for CRC and molecular markers for early diagnosis.

LncRNA loc105377478 promotes NPs-Nd2O3-induced inflammation in human bronchial epithelial cells through the ADIPOR1/NF-κB axis

With the wide application of neodymium oxide nanoparticles (NPs-Nd₂O₃) in various fields, their health hazards have aroused public concern in recent years. However, data regarding the cytotoxicity of NPs-Nd₂O₃ is limited. In this study, we investigated the function and mechanism of long-chain non-coding RNAs (lncRNAs) in NPs-Nd₂O₃-induced airway inflammation. Treatment with NPs-Nd₂O₃ induced an inflammatory response in human bronchial epithelial cells (16HBE) by upregulating the expression of interleukin-6 (IL-6) and interleukin-8 (IL-8). The levels of LDH and intracellular ROS in the cells treated by various doses of NPs-Nd₂O₃ also increased significantly. After treatment with 10 μg/ml NPs-Nd₂O₃, RNA microarray and real-time quantitative polymerase chain reaction (qRT-PCR) showed a significant upregulation of lncRNA loc105377478. Functional experiments suggested lncRNA loc105377478 enhanced the expression of IL-6, IL-8 and ROS in NPs-Nd₂O₃-treated 16HBE cells, and it was further demonstrated that lncRNA loc105377478 promoted the activation of NF-κB by negatively regulating ADIPOR1 expression. Moreover, the expression of IL-6 and IL-8 in NPs-Nd₂O₃-treated 16HBE cells was regulated by lncRNA loc105377478, which was mediated by the NF-κB signaling pathway. In conclusion, lncRNA loc105377478 promotes NF-κB activation by negatively regulating ADIPOR1 expression, thereby upregulating the expression of IL-6 and IL-8 in 16HBE cells treated with NPs-Nd₂O₃.

Long noncoding RNA DLEU2 affects the proliferative and invasive ability of colorectal cancer cells

Emerging evidence indicates that long noncoding RNAs (lncRNAs) are closely associated with colorectal cancer (CRC) tumorigenesis. One example is lncRNA Deleted in Lymphocytic Leukemia 2 (DLEU2). However, how DLEU2 contributes to CRC is still poorly understood. This study sought to investigate the effects of DLEU2 on CRC pathogenesis, and the underlying mechanism involved. Using a quantitative real-time polymerase chain reaction (qRT-PCR) assay, we demonstrated that the expression levels of DLEU2 in 45 pairs of CRC tissues were higher than those in the corresponding normal colon mucosal tissues. In addition, CRC patients with high DLEU2 expression levels exhibited poor overall survival (OS) and recurrence-free survival (RFS), as determined by analyses and measurements from the GEO and GEPIA databases. When DLEU2 was silenced using short interfering RNA (siRNA) in CRC cell line, the results demonstrated that DLEU2 silencing suppressed CRC cell tumorigenesis in vitro, which was associated with decreased expression of cyclin dependent kinase 6(CDK6), ZEB1, and ZEB2 as well as enhancing the expression of Cyclin-dependent kinase inhibitor 1A (CDKN1A). Taken together, the results of this study suggested that DLEU2 may play critical roles in the progression of CRC and may serve as a prognostic biomarker for CRC.

Development of a Ten-lncRNA Signature Prognostic Model for Breast Cancer Survival: A Study with the TCGA Database

Long noncoding RNA (lncRNA) plays a critical role in the development of tumors. The aim of our study was construction of a lncRNA signature model to predict breast cancer (BRCA) patient survival. We downloaded RNA-seq data and relevant clinical information from the Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNA were computed using the “edgeR” package and subjected to the univariate and multivariate Cox regression analysis. Corresponding protein-coding genes were used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis. Finally, 521 differentially expression lncRNA were obtained. We constructed a ten-lncRNA signature model (LINC01208, RP5-1011O1.3, LINC01234, LINC00989, RP11-696F12.1, RP11-909N17.2, CTC-297N7.9, CTA-384D8.34, CTC-276P9.4, and MAPT-IT1) to predict BRCA patient survival using the multivariate Cox proportional hazard regression model. The C-index was 0.712, and AUC scores of training, test, and entire sets were 0.746, 0.717, and 0.732, respectively. Univariate Cox regression analysis indicated that age, tumor status, N status, M status, and risk score were significantly related to overall survival in patients with BRCA. Further, the multivariate analysis showed that risk score and M status had outstanding independent prognostic values, both with p < 0.001. The Gene Ontology (GO) function and KEEG pathway analysis was primarily enriched in immune response, receptor binding, external surface of plasma membrane, signal transduction, cytokine-cytokine receptor interaction, and cell adhesion molecules (CAMs). Finally, we constructed a ten-lncRNA signature model that can serve as an independent prognostic model to predict BRCA patient survival.

A novel prognostic signature of immune-related genes for patients with colorectal cancer

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers with an estimated 1.8 million new cases worldwide and associated with high mortality rates of 881 000 CRC-related deaths in 2018. Screening programs and new therapies have only marginally improved the survival of CRC patients. Immune-related genes (IRGs) have attracted attention in recent years as therapeutic targets. The aim of this study was to identify an immune-related prognostic signature for CRC. To this end, we combined gene expression and clinical data from the CRC data sets of The Cancer Genome Atlas (TCGA) into an integrated immune landscape profile. We identified a total of 476 IRGs that were differentially expressed in CRC vs normal tissues, of which 18 were survival related according to univariate Cox analysis. Stepwise multivariate Cox proportional hazards analysis established an immune-related prognostic signature consisting of SLC10A2, FGF2, CCL28, NDRG1, ESM1, UCN, UTS2 and TRDC. The predictive ability of this signature for 3- and 5-year overall survival was determined using receiver operating characteristics (ROC), and the respective areas under the curve (AUC) were 79.2% and 76.6%. The signature showed moderate predictive accuracy in the validation and GSE38832 data sets as well. Furthermore, the 8-IRG signature correlated significantly with tumour stage, invasion, lymph node metastasis and distant metastasis by univariate Cox analysis, and was established an independent prognostic factor by multivariate Cox regression analysis for CRC. Gene set enrichment analysis (GSEA) revealed a relationship between the IRG prognostic signature and various biological pathways. Focal adhesions and ECM-receptor interactions were positively correlated with the risk scores, while cytosolic DNA sensing and metabolism-related pathways were negatively correlated. Finally, the bioinformatics results were validated by real-time RT-qPCR. In conclusion, we identified and validated a novel, immune-related prognostic signature for patients with CRC, and this signature reflects the dysregulated tumour immune microenvironment and has a potential for better CRC patient management.

LncRNA WDFY3-AS2 suppresses proliferation and invasion in oesophageal squamous cell carcinoma by regulating miR-2355-5p/SOCS2 axis

Long non‐coding RNAs (lncRNAs) widely participate in ESCC development and progression; however, the prognostic factors and therapeutic strategies implicated in ESCC development and progression remain to be under investigation. The purpose of the current study was to explore whether WDFY3‐AS2 may be a potential prognostic factor and investigate its biological functions in ESCC. Here, WDFY3‐AS2 was frequently down‐regulated in ESCC tissues and cells, and its expression was correlated with TNM stage, lymph node metastasis and poor prognosis of ESCC patients. Moreover, WDFY3‐AS2 down‐regulation significantly promoted cell proliferation and invasion, whereas WDFY3‐AS2 up‐regulation markedly suppressed cell proliferation and invasion in ESCC EC9706 and TE1 cells, coupled with EMT phenotype alterations. WDFY3‐AS2 functioned as a competing endogenous RNA (ceRNA) for sponging miR‐2355‐5p, further resulted in the up‐regulation of its target gene SOCS2, followed by suppression of JAK2/Stat5 signalling pathway, to suppress ESCC cell proliferation and invasion in EC9706 and TE1 cells. These findings suggest that WDFY3‐AS2 may participate in ESCC development and progression, and may be a novel prognostic factor for ESCC patients, and thus targeting WDFY3‐AS2/miR‐2355‐5p/SOCS2 signalling axis may be a novel therapeutic strategy for ESCC patients.