Dataset Information

Epigenetically silenced linc00261 contributes to the metastasis of hepatocellular carcinoma via inducing the deficiency of FOXA2 transcription.

ABSTRACT: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. In recent decades, long non-coding RNAs (lncRNAs) have attracted increasing attention and have been reported to play important roles in human cancers, making them ideal candidates for precise disease assessment and treatment. Our previous study found that the loss of linc00261 was significantly correlated with the malignant biological behaviors of HCC, particularly MVI, and serves as an excellent independent prognostic factor for recurrence-free survival. In this study, our in-depth research demonstrated that linc00261 inhibits epithelial-mesenchymal transition (EMT) in liver cancer cells, thereby suppressing migration, invasion, and the formation of lung metastatic lesions. Moreover, linc00261 and its neighbor gene FOXA2 were positively correlated in HCC, the gain- and loss-of-function analyses indicated that linc00261 transcriptionally promotes the expression of FOXA2. Additionally, bioinformatic analysis and rescue assays confirmed that linc00261 partially suppresses migration, invasion, and EMT by upregulating FOXA2 expression. Molecular mechanism studies showed that linc00261 transcriptionally upregulates FOXA2 in cis by recruiting SMAD3. Finally, we identified EZH2 is responsible for linc00261 transcription repression via modulating trimethylation of H3K27 at Lys27 (H3K27Me3), both EZH2 and H3K27Me3 were negatively correlated with linc00261 expression in HCC. In conclusion, these findings demonstrated a crucial role of linc00261 in HCC metastasis, and that EZH2/linc00261/FOXA2 axis might reveal potential prognostic factors and be applied as therapeutic targets for HCC metastasis.

SUBMITTER: Chen Z

PROVIDER: S-EPMC7840721 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Epigenetically silenced linc00261 contributes to the metastasis of hepatocellular carcinoma via inducing the deficiency of FOXA2 transcription.

Chen Zhanjun Z Xiang Leyang L Hu Zhigang Z Ou Huohui H Liu Xiao X Yu Lili L Chen Wancheng W Jiang Lei L Yu Qiangfeng Q Fang Yinghao Y Xu Yuyan Y Liu Qin Q Huang Yu Y Li Xianghong X Yang Dinghua D

American journal of cancer research 20210101 1

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. In recent decades, long non-coding RNAs (lncRNAs) have attracted increasing attention and have been reported to play important roles in human cancers, making them ideal candidates for precise disease assessment and treatment. Our previous study found that the loss of linc00261 was significantly correlated with the malignant biological behaviors of HCC, particularly MVI, and serves as an excellent independent prognos ...[more]

PMID: 33520374

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Project description:Background: Due to the limitations of strategies for its early diagnosis and treatment, pancreatic cancer (PC) remains a substantial human health threat. We previously discovered a methylation-mediated lncRNA, LINC00261, which is downregulated in PC tissues. However, the underlying role of LINC00261 in PC remains largely unknown. Methods: Quantitative real-time PCR and in situ hybridization were performed to evaluate the expression levels of LINC00261 in PC, adjacent nontumor and normal pancreas tissues. The clinical significance of LINC00261 was assessed in multicenter PC samples. The functions of LINC00261 in PC were investigated by gain- and loss-of-function assays in vitro and in vivo. Potential downstream pathways and mechanisms were explored via RNA sequencing and bioinformatic analyses. RNA immunoprecipitation and chromatin immunoprecipitation assays were used to validate the underlying mechanisms. Pyrosequencing and targeted demethylation of the LINC00261 promoter were performed to explore the upstream epigenetic mechanisms and therapeutic potential. Results: LINC00261 was significantly downregulated in PC tissues, and its expression was positively associated with the prognosis of PC patients. Phenotypic studies indicated that LINC00261 overexpression significantly suppressed PC cell proliferation, migration and metastasis in vitro and in vivo. c-Myc was identified as a downstream target of LINC00261. LINC00261 repressed c-Myc transcription by physically interacting and binding with the bromo domain of p300/CBP, preventing the recruitment of p300/CBP to the promoter region of c-Myc and decreasing the H3K27Ac level. Moreover, the methylation level of the LINC00261 promoter was high in PC tissues and was correlated with poor prognosis. Targeted demethylation of the LINC00261 promoter inhibited PC progression both in vitro and in vivo. Conclusions: Our findings indicate that methylation-mediated LINC00261 suppresses PC progression by epigenetically repressing c-Myc expression. These findings expand the therapeutic potential of LINC00261, possibly providing evidence to support the development of epigenetic drugs or therapeutic strategies. This research adds further insights into the etiology of PC and indicates that LINC00261 may be a prognostic and therapeutic target in PC.

Project description:BACKGROUND:The majority of breast cancer patients die of metastasis rather than primary tumors, whereas the molecular mechanisms orchestrating cancer metastasis remains poorly understood. Long noncoding RNAs (lncRNA) have been shown to regulate cancer occurrence and progression. However, the lncRNAs that drive metastasis in cancer patients and their underlying mechanisms are still largely unknown. METHODS:lncRNAs highly expressed in metastatic lymph nodes were identified by microarray. Survival analysis were made by Kaplan-Meier method. Cell proliferation, migration, and invasion assay was performed to confirm the phenotype of LINC02273. Tail vein model and mammary fat pad model were used for in vivo study. RNA pull-down and RIP assay were used to confirm the interaction of hnRNPL and LINC02273. Chromatin isolation by RNA purification followed by sequencing (ChIRP-seq), RNA-seq, ChIP-seq, and luciferase reporter assay reveal hnRNPL-LINC02273 regulates AGR2. Antisense oligonucleotides were used for in vivo treatment. RESULTS:We identified a novel long noncoding RNA LINC02273, whose expression was significantly elevated in metastatic lesions compared to the primary tumors, by genetic screen of matched tumor samples. Increased LINC02273 promoted breast cancer metastasis in vitro and in vivo. We further showed that LINC02273 was stabilized by hnRNPL, a protein increased in metastatic lesions, in breast cancer cells. Mechanistically, hnRNPL-LINC02273 formed a complex which activated AGR2 transcription and promoted cancer metastasis. The recruitment of hnRNPL-LINC02273 complex to AGR2 promoter region epigenetically upregulated AGR2 by augmenting local H3K4me3 and H3K27ac levels. Combination of AGR2 and LINC02273 was an independent prognostic factor for predicting breast cancer patient survival. Moreover, our data revealed that LINC02273-targeting antisense oligonucleotides (ASO) substantially inhibited breast cancer metastasis in vivo. CONCLUSIONS:Our findings uncover a key role of LINC02273-hnRNPL-AGR2 axis in breast cancer metastasis and provide potential novel therapeutic targets for metastatic breast cancer intervention.

Dataset Information

Epigenetically silenced linc00261 contributes to the metastasis of hepatocellular carcinoma via inducing the deficiency of FOXA2 transcription.

Publications

Epigenetically silenced linc00261 contributes to the metastasis of hepatocellular carcinoma via inducing the deficiency of FOXA2 transcription.

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