High KCNQ1OT1 expression might independently predict shorter survival of colon adenocarcinoma

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

LncRNA KCNQ1OT1: Molecular mechanisms and pathogenic roles in human diseases

Long non-coding RNAs (lncRNAs) exhibit a length more than 200 nucleotides and they are characterized by non-coding RNAs (ncRNA) not encoded into proteins. Over the past few years, the role and development of lncRNAs have aroused the rising attention of researchers. To be specific, KCNQ1OT1, the KCNQ1 opposite strand/antisense transcript 1, is clearly classified as a regulatory ncRNA. KCNQ1OT1 is capable of interacting with miRNAs, RNAs and proteins, thereby affecting gene expression and various cell functions (e.g., cell proliferation, migration, epithelial-mesenchymal transition (EMT), apoptosis, viability, autophagy and inflammation). KCNQ1OT1 is dysregulated in a wide range of human diseases (e.g., cardiovascular disease, cancer, diabetes, osteoarthritis, osteoporosis and cataract), and it is speculated to act as a therapeutic target for treating various human diseases. On the whole, this review aims to explore the biological functions, underlying mechanisms and pathogenic roles of KCNQ1OT1 in human diseases.

Long non-coding RNAs as the critical regulators of doxorubicin resistance in tumor cells

Resistance against conventional chemotherapeutic agents is one of the main reasons for tumor relapse and poor clinical outcomes in cancer patients. Various mechanisms are associated with drug resistance, including drug efflux, cell cycle, DNA repair and apoptosis. Doxorubicin (DOX) is a widely used first-line anti-cancer drug that functions as a DNA topoisomerase II inhibitor. However, DOX resistance has emerged as a large hurdle in efficient tumor therapy. Furthermore, despite its wide clinical application, DOX is a double-edged sword: it can damage normal tissues and affect the quality of patients’ lives during and after treatment. It is essential to clarify the molecular basis of DOX resistance to support the development of novel therapeutic modalities with fewer and/or lower-impact side effects in cancer patients. Long non-coding RNAs (lncRNAs) have critical roles in the drug resistance of various tumors. In this review, we summarize the state of knowledge on all the lncRNAs associated with DOX resistance. The majority are involved in promoting DOX resistance. This review paves the way to introducing an lncRNA panel marker for the prediction of the DOX response and clinical outcomes for cancer patients.

Long Noncoding RNA KCNQ1OT1 is a Prognostic Biomarker and mediates CD8+ T cell exhaustion by regulating CD155 Expression in Colorectal Cancer

Background: Long noncoding RNA KCNQ1 opposite strand/antisense transcript 1 (lncRNA KCNQ1OT1) is abnormally expressed in various solid tumors. The purpose of this study was to explore the prognostic value and potential functional role of lncRNA KCNQ1OT1 across cancers. Methods: We performed a meta-analysis of published literature to evaluate the prognostic value of lncRNA KCNQ1OT1 across cancers. Verification, functional analysis, and genomic variation analysis were performed using the GEPIA, TIMER, and LnCeVar databases. According to the immune cell infiltration level, we established a prognostic model of lncRNA KCNQ1OT1 expression using public datasets of TIMER. We used quantitative real-time polymerase chain reaction (RT-qPCR) and western blot to detect the expression levels of lncRNA KCNQ1OT1 and the CD155 protein in colorectal cancer (CRC) tissues and cell lines. Then, a lncRNA KCNQ1OT1-knockdown cell line was cocultured to explore the role of lncRNA KCNQ1OT1 and CD155 in the T cell response by flow cytometric analysis. Results: Our results showed that the high expression of lncRNA KCNQ1OT1 was significantly related to poor overall survival across cancers, especially CRC. Interestingly, we found that COAD patients with high lncRNA KCNQ1OT1 expression and high CD8⁺ T cell infiltration levels had a worse prognosis than those with low lncRNA KCNQ1OT1 expression and high CD8⁺ T cell infiltration levels. Moreover, lncRNA KCNQ1OT1 and CD155 showed significantly higher expression in CRC tissue than in normal tissue, and lncRNA KCNQ1OT1 expression was positively correlated with CD155 expression in CRC. Finally, knockdown of lncRNA KCNQ1OT1 reduced CD155 expression in HCT116 and SW620 cells and enhanced the immune response in coculture with CD8⁺ T cells. Conclusions: High lncRNA KCNQ1OT1 expression is significantly correlated with poor prognosis of CRC patients and mediates the CD8⁺ T cell response in CRC. These findings indicate that lncRNA KCNQ1OT1 is a prognostic biomarker and potential immune therapeutic target for enhancing the CD8⁺ T cell response in CRC.

Biomarker Discovery for the Carcinogenic Heterogeneity Between Colon and Rectal Cancers Based on lncRNA-Associated ceRNA Network Analysis

Background

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Emerging evidence has revealed that risk factors and metastatic patterns differ greatly between colon and rectal cancers. However, the molecular mechanism underlying their pathogenic differences remains unclear. Therefore, we here aimed to identify non-coding RNA biomarkers based on lncRNA-associated ceRNA network (LceNET) to elucidate the carcinogenic heterogeneity between colon and rectal cancers.

Methods

A global LceNET in human was constructed by employing experimental evidence-based miRNA-mRNA and miRNA-lncRNA interactions. Then, four context-specific ceRNA networks related to cancer initiation and metastasis were extracted by mapping differentially expressed lncRNAs, miRNAs and mRNAs to the global LceNET. Notably, a novel network-based bioinformatics model was proposed and applied to identify lncRNA/miRNA biomarkers and critical ceRNA triplets for understanding the carcinogenic heterogeneity between colon and rectal cancers. Moreover, the identified biomarkers were further validated by their diagnostic/prognostic performance, expression pattern and correlation analysis.

Results

Based on network modeling, lncRNA KCNQ1OT1 (AUC>0.85) and SNHG1 (AUC>0.94) were unveiled as common diagnostic biomarkers for the initiation and metastasis of colon and rectal cancers. qRT-PCR analysis uncovered that these lncRNAs had significantly higher expression level in CRC cell lines with high metastatic potential. In particular, KCNQ1OT1 and SNHG1 function in colon and rectal cancers via different ceRNA mechanisms. For example, KCNQ1OT1/miR-484/ANKRD36 axis was involved in the initiation of colon cancer, while KCNQ1OT1/miR-181a-5p/PCGF2 axis was implicated in the metastasis of rectal cancer; the SNHG1/miR-484/ORC6 axis played a role in colon cancer, while SNHG1/miR-423-5p/EZH2 and SNHG1/let-7b-5p/ATP6V1F axes participated in the initiation and metastasis of rectal cancer, respectively. In these ceRNA triplets, miR-484, miR-181a-5p, miR-423-5p and let-7b-5p were identified as miRNA biomarkers with excellent distinguishing ability between normal and tumor tissues, and ANKRD36, PCGF2, EZH2 and ATP6V1F were closely related to the prognosis of corresponding cancer.

Conclusion

The landscape of lncRNA-associated ceRNA network not only facilitates the exploration of non-coding RNA biomarkers, but also provides deep insights into the oncogenetic heterogeneity between colon and rectal cancers, thereby contributing to the optimization of diagnostic and therapeutic strategies of CRC.

LncRNA KCNQ1OT1 facilitates the progression of bladder cancer by targeting MiR-218-5p/HS3ST3B1

Long non-coding RNA (lncRNA) is characterized by biological function in diverse cancers. LncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) is well acknowledged to regulate various cancers, while its role in bladder cancer remains unclear. In the present study, we aimed at probing into the impact and detailed mechanisms of KCNQ1OT1 in bladder cancer progression. In this study, we demonstrated that KCNQ1OT1 expression in bladder cancer tissues was notably up-regulated compared with in normal adjacent tissues, and KCNQ1OT1 modulated the malignant phenotypes of bladder cancer cells. Moreover, it was validated that KCNQ1OT1 could specifically bind to miR-218-5p and reduce its expression. Overexpressed miR-218-5p would inhibit the proliferation and metastasis of bladder cancer cells while facilitating apoptosis. In terms of Mechanism, Heparan Sulfate-Glucosamine 3-Sulfotransferase 3B1 (HS3ST3B1) was validated as a target gene of miR-218-5p, and could be regulated by KCNQ1OT1 indirectly. In conclusion, KCNQ1OT1 can promote the progression of bladder cancer through regulation of miR-218-5p/HS3ST3B1, which is expected to serve as a new therapeutic target for bladder cancer.

Long non-coding RNA KCNQ1OT1 up-regulates CTNND1 by sponging miR-329-3p to induce the proliferation, migration, invasion, and inhibit apoptosis of colorectal cancer cells

Background

Long non-coding RNAs (lncRNAs) have been certified to be involved in the occurrence and growth of diverse cancers, including CRC. The purpose of the research was to explore the effects of lncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) on proliferation, migration, invasion, and apoptosis in CRC cells and its mechanism.

Methods

The levels of KCNQ1OT1 and miR-329-3p were examined by quantitative real-time polymerase chain reaction (qRT-PCR) in CRC tissues and cells. The mRNA and protein levels of catenin delta-1 (CTNND1) were measured by qRT-PCR and western blot analysis, respectively. The targets of KCNQ1OT1 and miR-329-3p were predicted by online software and confirmed by luciferase reporter assay. The cell proliferation, migration, invasion, and apoptosis were examined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), transwell, and apoptosis assay. The expression levels of CyclinD1, Bcl-2, MMP9, Cleaved-casp-3, and E-cadherin in SW480 and LS1034 cells were gauged by western blot analysis. Xenograft tumor model was structured to prove the biological role of KCNQ1OT1 of CRC in vivo.

Results

The levels of KCNQ1OT1 and CTNND1 were significantly increased in CRC tissues and cells. Knockdown of KCNQ1OT1 suppressed proliferation, migration, invasion, and induced apoptosis in CRC cells. Conversely, CTNND1 overexpression reversed the impact of KCNQ1OT1 knockdown on CRC cells. Moreover, CTNND1 was verified as a direct target of miR-329-3p, and miR-329-3p could specially bind to KCNQ1OT1. Also, the down-regulation of KCNQ1OT1 triggered the CRC progress by up-regulating CTNND1 expression in CRC cells. Besides, KCNQ1OT1 knockdown inhibited CRC tumor growth through the miR-329-3p/CTNND1 axis in vivo.

Conclusion

Our results indicated that KCNQ1OT1 could positively regulate CTNND1 expression by sponging miR-329-3p, thereby boosting the progression of CRC. Our findings provided the underlying therapy targets for CRC.

The YTH Domain Family of N6-Methyladenosine "Readers" in the Diagnosis and Prognosis of Colonic Adenocarcinoma

To profile the landscape of methylation N⁶ adenosine (m⁶A) RNA regulators in colonic adenocarcinoma (COAD) and to explore potential diagnostic and prognostic biomarkers, we assessed the differential expression patterns of m⁶A RNA methylation regulators between 418 COAD patients and 41 controls based on profiling from The Cancer Genome Atlas (TCGA) database. We plotted the receiver operating characteristic (ROC) curves and calculated the area under the curve (AUC) values to estimate the discrimination ability. The relationship between the expression of m⁶A RNA methylation regulators and clinicopathological characteristics was explored. Kaplan-Meier plotter, log-rank test, and Cox regression were used and a nomogram was created to explore the prognostic significance of m⁶A-related genes in overall survival at the mRNA level. Pathway analysis was performed by gene set enrichment analysis (GSEA) using TCGA dataset, and a coexpression network was built based on the STRING database. We observed that YTHDF1, METTL3, and KIAA1429 were significantly upregulated, while YTHDF3, YTHDC2, METTL14, and ALKBH5 were significantly downregulated in COAD samples compared to normal samples. YTHDF1 had the highest diagnostic value. Low expression of YTHDF3 predicted a poor survival rate in COAD patients. YTHDC2 was related to sex and showed a downward trend as clinical stage increased. Our results indicate that the YT521-B homology (YTH) domain family (“readers”), especially YTHDF1, YTHDF3, and YTHDC2, might play a significant role in the detection, progression, and prognosis of COAD, indicating that they are promising cancer biomarkers.

Effect of knockdown of long-chain noncoding RNA KCNQ1 overlapping transcript 1 on growth and cisplatin sensitivity of HGC-27 cells

BACKGROUND

Gastric cancer (GC) had become one of the malignant tumors that threaten the safety of human life. At present, the molecular mechanism of the occurrence and development of GC has not been fully elucidated. The regulatory role of long-chain noncoding RNAs in these processes has not yet been elucidated.

AIM

To investigate the effect of KCNQ1 overlapping transcript 1 (KCNQ1OT1) on the proliferation, invasion, migration, and cisplatin sensitivity of HGC-27 cells.

METHODS

HCN-27 cells transfected with KCNQ1OT1-siRNA were used as a KCNQ1OT1-siRNA group, HGC-27 cells transfected with negative control siRNA were used as an NC-siRNA group, and normally cultured cells were used as a control group. After treatment of cells in the KCNQ1OT1-siRNA group and NC-siRNA group with cisplatin, cell viability was measured by Cell Counting Kit-8 assay, and the half-maximal inhibitory concentration (IC50) was calculated. Real-time quantitative polymerase chain reaction, Transwell assay, flow cytometry, and Western blot were used to detect KCNQ1OT1 expression level, cell proliferation, invasion, and migration, cycle distribution, and the expression of E-cadherin, N-cadherin, Vimentin, P-glycoprotein (P-gp), and multidrug resistance associated protein 1 (MRP1), respectively.

RESULTS

Compared with the control group, there was no significant change in the indexes in the NC-siRNA group (P > 0.05). Compared with the control group or NC-siRNA group, the expression level of KCNQ1OT1, the percentages of cells in S phase and G2/M phase, the ability of cell proliferation, invasion, and migration, and the expression levels of N-cadherin and Vimentin in cells of the KCNQ1OT1-siRNA group were significantly reduced, while the percentage of cells in G0/G1 phase was significantly reduced (P > 0.05). Compared with the NC-siRNA group, the protein levels of P-gp and MRP1 in the KCNQ1OT1-siRNA group were significantly reduced (P < 0.05), and the IC50 was significantly reduced (P < 0.05).

CONCLUSION

KCNQ1OT1 knockdown can inhibit the proliferation, invasion, and migration of HGC-27 cells and enhance their sensitivity to cisplatin.

Integrative Clustering Reveals a Novel Subtype of Soft Tissue Sarcoma With Poor Prognosis

Background

Soft tissue sarcomas (STSs) are heterogeneous at the clinical and molecular level and need to be further sub-clustered for treatment and prognosis.

Materials And Methods

STSs were sub-clustered based on RNAseq and miRNAseq data extracted from The Cancer Genome Atlas (TCGA) through the combined process of similarity network fusion (SNF) and consensus clustering (CC). The expression and clinical characteristics of each sub-cluster were analyzed. The genes differentially expressed (lncRNAs, miRNAs, and mRNAs) between the poor prognosis and good prognosis clusters were used to construct a competing endogenous RNA (ceRNA) network. Functional enrichment analysis was conducted and a hub network was extracted from the constructed ceRNA network.

Results

A total of 247 STSs were classified into three optimal sub-clusters, and patients in cluster 2 (C2) had a significantly lower rate of survival. A ceRNA network with 91 nodes and 167 edges was constructed according to the hypothesis of ceRNA. Functional enrichment analysis revealed that the network was mainly associated with organism development functions. Moreover, LncRNA (KCNQ1OT1)-miRNA (has-miR-29c-3p)-mRNA (JARID2, CDK8, DNMT3A, TET1)-competing endogenous gene pairs were identified as hub networks of the ceRNA network, in which each component showed survival significance.

Conclusion

Integrative clustering analysis revealed that the STSs could be clustered into three sub-clusters. The ceRNA network, especially the subnetwork LncRNA (KCNQ1OT1)-miRNA (has-miR-29c-3p)-mRNA (JARID2, CDK8, DNMT3A, TET1) was a promising therapeutic target for the STS sub-cluster associated with a poor prognosis.

KCNQ1OT1 promotes ovarian cancer progression via modulating MIR-142-5p/CAPN10 axis

Background

Long non‐coding RNA (lncRNA) has been regarded as crucial regulator for cancer progression. Roles of KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in cancers including osteosarcoma and colon cancer have been previously reported. However, its role in ovarian cancer (OC) remains unclear.

Methods

Expression level of KCNQ1OT1 on OC cells and normal cell was analyzed with quantitative real‐time PCR. Gain and loss‐of‐function experiments were performed to analyze the biological roles of KCNQ1OT1 in OC. Moreover, whether KCNQ1OT1 functions its role via mediating MICRORNA‐142‐5p (MIR‐142‐5p)/calpain 10 (CAPN10) axis was analyzed. In addition, effects of KCNQ1OT1, MIR‐142‐5p, and CAPN10 on overall survival of OC patients were analyzed at Kaplan–Meier plotter website.

Results

We showed KCNQ1OT1 was elevated expression in OC cells and indicated poorer overall survival of OC patients. Besides, we found KCNQ1OT1 could promote OC cell proliferation and migration in vitro. Moreover, MIR‐142‐5p was found reduced expression, while CAPN10 was found elevated expression in OC cells compared with normal cell. Kaplan–Meier curve analysis showed low MIR‐142‐5p or high CAPN10 expression were indicators for poorer overall survival of OC patients. At length, we showed KCNQ1OT1 could regulate OC development via MIR‐142‐5p/CAPN10 axis.

Conclusions

Taken together, KCNQ1OT1 upregulates CAPN10 expression via sponging MIR‐142‐5p, thus promoting the proliferation and migration of OC.

LncRNA KCNQ1OT1 contributes to the progression and chemoresistance in acute myeloid leukemia by modulating Tspan3 through suppressing miR-193a-3p

AIMS

Acute myeloid leukemia (AML) is an aggressive cancer that invariably produces drug resistance after treatment. The aim is to explore the role of lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) and associated novel mechanisms in the progression and chemoresistance of AML.

MAIN METHODS

The expression of KCNQ1OT1, miR-193a-3p, and Tspan3 was measured by qRT-PCR. The values of IC50 for adriamycin (ADR) and the ability of proliferation were analyzed by CCK-8 assay. Cell migration and invasion were assessed by transwell assay. Cell apoptosis was monitored by flow cytometry assay. The expression of Tspan3, MRP1, P-gp and LRP at the protein level was quantified by western blot. The relationship between miR-193a-3p and KCNQ1OT1 or Tspan3 was predicted by bioinformatics tool Diana and verified by dual-luciferase reporter assay, RIP assay or RNA pull-down assay.

KEY FINDINGS

KCNQ1OT1 and Tspan3 were up-regulated, while miR-193a-3p was down-regulated in ADR resistant AML samples and cells. KCNQ1OT1 knockdown reduced ADR resistance, inhibited proliferation, migration and invasion but promoted apoptosis of ADR resistant AML cells, miR-193a-3p inhibition reversed these effects. MiR-193a-3p was a target of KCNQ1OT1 and combined with Tspan3 3' untranslated region (3' UTR). Enrichment of miR-193a-3p decreased ADR resistance, inhibited proliferation, migration and invasion and stimulated apoptosis in ADR resistant AML cells, but Tspan3 overexpression overturned these impacts.

SIGNIFICANCE

KCNQ1OT1 aggravates AML progression and chemoresistance to ADR by inducing Tspan3 expression via adsorbing miR-193a-3p in ADR resistant AML cells, providing a theoretical basis for the treatment of AML with chemoresistance.