METTL14 suppresses proliferation and metastasis of colorectal cancer by down-regulating oncogenic long non-coding RNA XIST

Abstract

Background: N6-methyladenosine (m6A) is the most prevalent RNA epigenetic regulation in eukaryotic cells. However, understanding of m6A in colorectal cancer (CRC) is very limited. We designed this study to investigate the role of m6A in CRC.Methods: Expression level of METTL14 was extracted from public database and tissue array to investigate the clinical relevance of METTL14 in CRC. Next, gain/loss of function experiment was used to define the role of METTL14 in the progression of CRC. Moreover, transcriptomic sequencing (RNA-seq) was applied to screen the potential targets of METTL14. The specific binding between METTL14 and presumed target was verified by RNA pull-down and RNA immunoprecipitation (RIP) assay. Furthermore, rescue experiment and methylated RNA immunoprecipitation (Me-RIP) were performed to uncover the mechanism.Results: Clinically, loss of METTL14 correlated with unfavorable prognosis of CRC patients. Functionally, knockdown of METTL14 drastically enhanced proliferative and invasive ability of CRC cells in vitro and promoted tumorigenicity and metastasis in vivo. Mechanically, RNA-seq and Me-RIP identified lncRNA XIST as the downstream target of METTL14. Knockdown of METTL14 substantially abolished m6A level of XIST and augmented XIST expression. Moreover, we found that m6A-methylated XIST was recognized by YTHDF2, a m6A reader protein, to mediate the degradation of XIST. Consistently, XIST expression negatively correlated with METTL14 and YTHDF2 in CRC tissues.Conclusion: Our findings highlight the function and prognostic value of METTL14 in CRC and extend the understanding of the importance of RNA epigenetics in cancer biology.

Downregulated METTL14 Expression Correlates with Breast Cancer Tumor Grade and Molecular Classification

“…The catalytic protein methyltransferase-like 14 (METTL14) participates in mediate cellular N 6 -methyladenosine (m 6 A) deposition [ 10 ] and is closely related to the occurrence and development of malignant tumors [ 11 – 23 ]. METTL14 plays a complex role in malignant tumors: low levels of METTL14 expression are found in hepatocellular carcinoma [ 13 ], colorectal cancer [ 14 , 16 , 17 ], bladder cancer [ 15 ], gastric cancer [ 18 ], childhood ETV6/RUNX1-positive acute lymphoblastic leukemia [ 19 ], and papillary thyroid carcinoma [ 20 ], where METTL14 functions as a tumor suppressor [ 13 – 18 ], whereas levels of METTL14 expression are high in pancreatic cancer [ 21 , 22 ] and acute myeloid leukemia [ 23 ], where this protein functions as a tumor promoter. In breast cancer, contrasting findings have been reported from analyses of the expression and function of METTL14.…”

Identification of Potential Prognostic Biomarkers for Tongue Squamous Cell Carcinoma

“…knockdown substantially abolished the m 6 A level of XIST and augmented XIST expression [41] . Moreover, LINC00266-1, by encoding RPBP to strengthen m 6 A recognition on RNAs, ultimately increases mRNA stability and expression [42] .…”

“…N 6 -methyladenosine (m 6 A) is the most prevalent modi cation in eukaryotic cells [12,13] and the most abundant modi cation in eukaryotic mRNAs and noncoding RNAs (ncRNAs) [14] . A large body of evidence has demonstrated that the m 6 A modi cation plays a vital role in RNA translation, stability and alternative splicing, and perturbations in m 6 A components are associated with human diseases, especially cancers [15][16][17][18] . NcRNAs exhibit patterns of m 6 A modi cations that are distinct from those of mRNAs [19,20] .…”

Analysis of N6-methyladenosine (m6A) methyltransferase reveals METTL14 and ZC3H13 as tumor suppressor genes in breast cancer

“…METTL3 was also over-expressed in pancreatic cancer, bladder cancer, glioma and gastric cancer, and promotes proliferation, invasion and drug resistance of cancer cells [38][39][40][41]. By contrast, METTL14 was down-regulated in colorectal cancer and hepatocellular carcinoma, and could inhibit cancer cells growth and metastasis by regulating m6A-dependent primary microRNA processing [12,42].…”

“…WTAP expression was up-regulated in hepatocellular carcinoma, WTAP-mediated m6A modi cation led to epigenetic silencing of the tumor suppressor gene ETS1, and promoted the progression of hepatocellular carcinoma by regulating the cell cycle [11]. The expression of METTL14 was down-regulated in colorectal cancer, which indicated a poor prognosis of patients, and promoted the proliferation and invasion of tumor cells by inhibiting the degradation of the oncogene XIST [12]. However, the abnormal expression of m6A "writer" proteins in breast cancer is still remain largely unknown, and the gene targets and molecules mechanisms involved downstream also need to be further elucidated.…”