Methyl CpG binding protein 2 promotes colorectal cancer metastasis by regulating N6 -methyladenosine methylation through methyltransferase-like 14.

RNA N6 -methyladenosine (m6 A) is an emerging regulatory mechanism for tumor progression in several types of cancer. However, the underlying regulation mechanisms of m6 A methylation in colorectal cancer (CRC) remain unknown. Although the oncogenic function of methyl CpG binding protein 2 (MeCP2) has been reported, it is still unclear whether MeCP2 could alter RNA m6 A methylation state. Here, we systematically identified MeCP2 as a prometastasis gene to regulate m6 A methylation in CRC. Interestingly, MeCP2 could bind to methyltransferase-like 14 (METTL14) to coregulate tumor suppressor Kruppel-like factor 4 (KLF4) expression through changing m6 A methylation modification. Furthermore, insulin-like growth factor 2 mRNA-binding protein 2 recognized the unique modified m6 A methylation sites to enhance KLF4 mRNA stability. Taken together, these findings highlight the novel function of MeCP2 for regulating m6 A methylation and reveal the underlying molecular mechanism for the interaction between MeCP2 and METTL14, which offers a better understanding of CRC progression and metastasis.

Iroquois Homeobox 5 Negatively Regulated by miRNA-147 Promotes the Proliferation, Metastasis, and Invasion by Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is one of the most common tumors worldwide and has one of the highest mortalities. The progression of OSCC is accompanied by changes in the levels of many genes. Iroquois homeobox 5 (IRX5), a novel protein involved in several embryonic developmental processes, has been found in recent years to play a significant role in regulating the growth of malignant tumors. However, its role and mechanism in OSCC are still unclear. In this study, we used nano-PCR to examine the levels of IRX5 in OSCC tissues. Through overexpression and knockdown experiments, we researched the role of IRX5 in regulating OSCC cell multiplication, metastasis, and epithelial-mesenchymal transition (EMT). The results demonstrated that IRX5 expression is higher in OSCC tissues in contrast to adjacent tissues. Overexpression of IRX5 promotes the multiplication, metastasis, invasion, and EMT of OSCC cells. Additional bioinformatics analysis showed that miRNA-147 can target the 3'UTR end of IRX5 and negatively regulate its expression, and overexpression of miRNA-147 can weaken the cancer-promoting effect of IRX5. In conclusion, this study found that IRX5 plays a role in promoting cancer in OSCC, and IRX5 is also negatively regulated by miRNA-147.

SRSF6-regulated alternative splicing that promotes tumour progression offers a therapy target for colorectal cancer.

OBJECTIVE: To investigate the molecular function of splicing factor SRSF6 in colorectal cancer (CRC) progression and discover candidate chemicals for cancer therapy through targeting SRSF6. DESIGN: We performed comprehensive analysis for the expression of SRSF6 in 311 CRC samples, The Cancer Genome Atlas and Gene Expression Omnibus (GEO) database. Functional analysis of SRSF6 in CRC was performed in vitro and in vivo. SRSF6-regulated alternative splicing (AS) and its binding motif were identified by next-generation RNA-sequencing and RNA immunoprecipitation sequencing (RIP-seq), which was validated by gel shift and minigene reporter assay. ZO-1 exon23 AS was investigated to mediate the function of SRSF6 in vitro and in vivo. Based on the analysis of domain-specific role, SRSF6-targeted inhibitor was discovered de novoby virtual screening in 4855 FDA-approved drugs and its antitumour effects were evaluated in vitroand in vivo. RESULTS: SRSF6 was frequently upregulated in CRC samples and associated with poor prognosis, which promoted proliferation and metastasis in vitro and in vivo. We identified SRSF6-regulated AS targets and discovered the SRSF6 binding motif. Particularly, SRSF6 regulates ZO-1 aberrant splicing to function as an oncogene by binding directly to its motif in the exon23. Based on the result that SRSF6 RRM2 domain plays key roles in regulating AS and biological function, indacaterol, a ß2-adrenergic receptor agonist approved for chronic obstructive pulmonary disease treatment, is identified as the inhibitor of SRSF6 to suppress CRC tumourigenicity. CONCLUSIONS: SRSF6 functions the important roles in mediating CRC progression through regulating AS, and indacaterol is repositioned as an antitumour drug through targeting SRSF6. ACCESSION NUMBERS: The accession numbers for sequencing data are SRP111763 and SRP111797.

Long noncoding RNA LINC01133 inhibits oral squamous cell carcinoma metastasis through a feedback regulation loop with GDF15.

BACKGROUND AND OBJECTIVES: Long noncoding RNAs (lncRNAs) play key roles in carcinoma metastasis. We aimed to investigate lncRNA LINC01133 in oral squamous cell carcinoma (OSCC) metastasis. METHODS: The RNA levels of LINC01133 and growth and differentiation factor 15 (GDF15) in tissue samples from OSCC patients, and OSCC cell lines were tested by real-time quantitative polymerase chain reaction (RT-qPCR). SPSS20.0 was used to perform statistical analysis of LINC01133 expression in clinical samples and correlate expression of LINC01133 and GDF15. Cell migration/invasion was assessed via transwell assays. Downstream genes of LINC01133 were screened using RNA-seq and validated by RT-qPCR. GDF15 protein levels were evaluated via Western blot analysis. RESULTS: LINC01133 was downregulated in OSCCs; higher expression of LINC01133 in OSCCs was correlated with less metastasis and better prognosis. LINC01133 inhibited OSCC cell migration and invasion. RNA-seq data showed that LINC01133 inhibited GDF15, and GDF15 could rescue inhibition of OSCC cell migration and invasion caused by LINC01133. Interestingly, GDF15 also inhibited LINC01133. Furthermore, a significant negative correlation between expression of LINC01133 and GDF15 was validated in the clinical study. CONCLUSIONS: Collectively, these data indicate that LINC01133 inhibited OSCC metastasis via a feedback regulation loop of reciprocal inhibition with GDF15, suggesting a new diagnostic and therapeutic target for OSCC.

The long non-coding RNA CYTOR drives colorectal cancer progression by interacting with NCL and Sam68.

BACKGROUND: Long non-coding RNAs (lncRNAs) function as key molecules in cancer progression. The lncRNA CYTOR plays oncogenic roles in multiple types of cancer, yet the detailed molecular mechanisms of those roles remain unknown. The aim of this study was to investigate the clinical significance, biological function and interacting partners of CYTOR in colorectal cancer (CRC). METHODS: A systematic and comprehensive analysis of CYTOR expression was performed in 138 CRC samples and in the TCGA and GEO databases. Biological function was investigated through knockdown and overexpression of CYTOR in vitro and in vivo. In addition, its protein binding partner was identified and validated using ChIRP-MS and RNA immunoprecipitation assays. Their key interaction sites on CYTOR were verified by CRISPR/Cas9 and a series of mutant constructs. Furthermore, the downstream targets of CYTOR were confirmed via immunoblotting and luciferase reporter assays. RESULTS: CYTOR was significantly up-regulated in CRC samples and associated with poor prognosis, promoting proliferation and metastasis in vitro and in vivo. NCL and Sam68 could recognize their specific motifs and directly bind to EXON1 of CYTOR. Moreover, EXON1 was the key functional site mediating the interaction of CYTOR with NCL and Sam68. NCL and Sam68 functioned as oncogenes to promote CRC progression. Furthermore, we confirmed that the heterotrimeric complex of CYTOR, NCL and Sam68 activated the NF-κB pathway and EMT to contribute to CRC progression. CONCLUSION: CYTOR plays important roles in CRC progression by interacting with NCL and Sam68 and may serve as a prognostic biomarker and/or an effective target for CRC therapies.

Long non-coding RNA linc00673 regulated non-small cell lung cancer proliferation, migration, invasion and epithelial mesenchymal transition by sponging miR-150-5p.

BACKGROUND: The function of a new long non-coding RNA linc00673 remains unclear. While identified as an oncogenic player in non-small cell lung cancer (NSCLC), linc00673 was found to be anti-oncogenic in pancreatic ductal adenocarcinoma (PDAC). However whether linc00673 regulated malignancy and epithelial mesenchymal transition (EMT) has not been characterized. METHODS: Cell proliferation was assessed using CCK-8 and EdU assays, and cell migration and invasion were assessed using scratch assays and transwell invasion assays. Epithelial mesenchymal transition was examined using western blot, qRT-PCR and immunofluorescence staining. Interaction between miRNA and linc00673 was determined using luciferase reporter assays. In vivo experiments were performed to assess tumor formation. In addition, the expression data of NSCLC specimens of TCGA and patient survival data were utilized to explore the prognostic significance of linc00673. RESULTS: In the present study, we found high linc00673 expression was associated with poor prognosis of NSCLC patients. In vitro experiments showed linc00673 knockdown reversed TGF-ß induced EMT, and miR-150-5p was predicted to target linc00673 through bioinformatics tools. Overexpression of miR-150-5p suppressed lin00673's expression while inhibition of miR-150-5p led to significant upregulation of lin00673, suggesting that linc00673 could be negatively regulated by miR-150-5p, which was further confirmed by the inverse correlation between linc00673 and miR-150-5p in NSCLC patients' specimen. Furthermore, we proved that miR-150-5p could directly target linc00673 through luciferase assay, so linc00673 could sponge miR-150-5p and modulate the expression of a key EMT regulator ZEB1 indirectly. In addition, miR-150-5p inhibition abrogated linc00673 silence mediated proliferation, migration, invasion and EMT suppressing effect. Moreover, the inhibition of linc00673 significantly attenuated the tumorigenesis ability of A549 cells in vivo. CONCLUSIONS: We validated linc00673 as a novel oncogenic lncRNA and demonstrated the molecular mechanism by which it promotes NSCLC, which will advance our understanding of its clinical significance.

Long non-coding RNA LINC01133 inhibits epithelial-mesenchymal transition and metastasis in colorectal cancer by interacting with SRSF6.

Long non-coding RNAs (lncRNAs) play crucial roles in many biological and pathological processes, including tumor metastasis. Here we reported a novel lncRNA, LINC01133 that was downregulated by TGF-ß, which could inhibit epithelial-mesenchymal transition (EMT) and metastasis in colorectal cancer (CRC) cells. An alternative splicing factor SRSF6 was identified to directly interact with LINC01133, and SRSF6 promoted EMT and metastasis in CRC cells independent of LINC01133 And we confirmed that the EMT process was regulated by LINC01133 in CRC cells dependent on the presence of SRSF6. The observation for LINC01133 to inhibit metastasis was also verified in vivo. Moreover clinical data showed that the LINC01133 expression was positively correlated with E-cadherin, and negatively correlated with Vimentin, and there was a robust association of low LIINC01133 expression in tumors with poor survival in CRC samples. These data suggest that LINC01133 inhibits the EMT and metastasis by directly binding to SRSF6 as a target mimic, and may serve as a prognostic biomarker and an effective target for anti-metastasis therapies for CRC.

HOTAIRM1 as a potential biomarker for diagnosis of colorectal cancer functions the role in the tumour suppressor.

Recent studies have revealed many different long noncoding RNAs (lncRNA), however, the investigation for their function and clinical value as tumour biomarkers has scarcely begun. Here, we found that expression of HOTAIRM1 was reduced in colorectal cancer (CRC) tissues compared with matched normal tissues, and plasma HOTAIRM1 levels in CRC patients were less than in controls. The cut-off point was chosen as 0.003 with a sensitivity of 64.00% and a specificity of 76.50% in the validation set. The performance of HOTAIRM1 was highly comparable to carcinoembryonic antigen (CEA), and better than CA19-9 and CA125. The combined assay of HOTAIRM1 and CEA raised the sensitivity and specificity to 84.00%. HOTAIRM1 knockdown resulted in obvious changes in expression of the cell proliferation related to genes and promoted cell proliferation. HOTAIRM1 plays a role of tumour suppressor in CRC; Down-regulation of HOTAIRM1 can serve as a biomarker for CRC, and combined HOTAIRM1 and CEA assay might provide a promising diagnosis for CRC.

GDF15 promotes EMT and metastasis in colorectal cancer.

Metastasis is the major cause of cancer deaths, and the epithelial-mesenchymal transition (EMT) has been considered to be a fundamental event in cancer metastasis. However, the role of growth differentiation factor 15 (GDF15) in colorectal cancer (CRC) metastasis and EMT remains poorly understood. Here, we showed that GDF15 promoted CRC cell metastasis both in vitro and in vivo. In addition, the EMT process was enhanced by GDF15 through binding to TGF-ß receptor to activate Smad2 and Smad3 pathways. Clinical data showed GDF15 level in tumor tissues, and the serum was significantly increased, in which high GDF15 level correlated with a reduced overall survival in CRC. Thus, GDF15 may promote colorectal cancer metastasis through activating EMT. Promisingly, GDF15 could be considered as a novel prognostic marker for CRC in the clinic.

MiR-22 regulates 5-FU sensitivity by inhibiting autophagy and promoting apoptosis in colorectal cancer cells.

Autophagy has become one of the most important mechanisms of chemotherapy resistance by supporting the survival of tumor cells under metabolic and therapeutic stress. Here, we showed that miR-22 inhibited autophagy and promoted apoptosis to increase the sensitivity of colorectal cancer (CRC) cells to 5-fluorouracil (5-FU) treatment both in vitro and in vivo. B-cell translocation gene 1 (BTG1) was identified as a new target of miR-22, which could reverse the inhibition of autophagy induced by miR-22. Thus, miR-22 may function as an important switch between autophagy and apoptosis to regulate 5-FU sensitivity through post-transcriptional silencing of BTG1. Promisingly, miR-22 could be considered as both a predictor of 5-FU sensitivity for personalized treatment and a therapeutic target for colorectal cancer.