Role of METTL3 in homocysteine-induced autophagy in mouse islet beta cells / 中国组织工程研究

BACKGROUND:Hyperhomocysteinemia is closely related to the function of islet β cells,but its specific molecular mechanism is not fully understood. OBJECTIVE:To investigate the role of N6 methyltransferase-like 3(METTL3)in homocysteine(Hcy)-induced autophagy of mouse islet β cells. METHODS:The 3rd and 4th generation mouse islet β cells were taken for the experiment.(1)Cell modeling and grouping:cells in control group were not treated with Hcy,while those in homocysteine group were treated with 100 μmol/L Hcy for 48 hours.(2)The mouse islet β-cells were transfected with the plasmids overexpressing Ad-METTL3 and si-METTL3 according to the instructions of LipofectamineTM 2000.Three different interfering fragments were designed,and the one with the best interfering efficiency was verified and screened by PCR.(3)After transfection,the cells were divided into control group,Hcy group,Ad-NC(negative control)+Hcy group,Ad-METTL3+Hcy group,si-NC(negative control)+Hcy group and si-METTL3+Hcy group.(4)qRT-PCR and western blot were used to detect the expression levels of METTL3 and autophagy-related proteins LC3Ⅱ/Ⅰ and p62 in cells.Insulin level was determined by ELISA to evaluate insulin secretion capacity of islet cells.Autophagy-related proteins and insulin level were detected after overexpression and interference with METTL3. RESULTS AND CONCLUSION:Compared with the control group,the expression level of LC3Ⅱ/Ⅰ was increased(P＜0.05),the expression of p62 was significantly reduced(P＜0.05),and the insulin secretion capacity was significantly decreased(P＜0.05)in the Hcy group.Compared with the control group,the protein and mRNA levels of METTL3 were reduced in the Hcy group(P＜0.05).After METTL3 silencing in islet β cells,Hcy further upregulated the expression of LC3Ⅱ/Ⅰ(P＜0.05),significantly dowregulated the expression of p62(P＜0.05),and increased the insulin level(P＜0.05).After overexpression of METTL3,Hcy significantly decreased the LC3Ⅱ/Ⅰ expression and increased the p62 expression in islet β cells(P＜0.05).To conclude,METTL3 is involved in the Hcy-induced autophagy regulation of islet β cells and plays a role in the regulation of insulin secretion.

Effect of methyltransferase like-3 on proliferation,migration and glutamine metabolism of esophageal cancer cells / 中国生物制品学杂志

@#Objective To investigate the expression of methyltransferase like-3(METTL3)in esophageal cancer tissues and its effects on the proliferation,migration,apoptosis and glutamine metabolism of cells.Methods The expression of METTL3 in esophageal cancer and paraneoplastic tissues was detected by qRT-PCR,Western blot and Immunohistochemistry. The effects of METTL3 inhibitor STM2457 on cell proliferation and migration of human esophageal squamous carcinoma cell lines Eca109 and KYSE150 were detected by CCK8,cloning assay,scratch test and Transwell assay. The effects on cell cycle and cell apoptosis were measured by flow cytometry and TUNEL experiment. TMT/iTRAQ quantitative proteomics experiment was used to identify the effects on downstream related signaling pathways. Glutamine assay,glutamate assay and Western blot were used to analyze the effect on glutamine metabolism in esophageal cancer cells.Results METTL3 gene expression was significantly upregulated in esophageal cancer tissues(t = 5. 024,P < 0. 000 1). STM2457 inhibited METTL3 expression in Eca109 and KYSE150 cells,significantly inhibited the cell proliferation and migration,blocked the cell cycle in G0/G1 phase,increased the cell apoptosis,decreased the glutamine uptake and glutamate production,and down-regulated the expression of glutamine-related proteins alanine-serine-cysteine transporter 2(ASCT2),glutaminase(GLS)and glutamate dehydrogenase 1(GLUD1). The glutamine uptake and glutamate production in Eca109 and KYSE150 cells decreased significantly after METTL3 knockdown(glutamine uptake:t = 24. 52-41. 01,each P < 0. 01;glutamate production:t = 8. 431-11. 83,each P < 0. 01);After METTL3 overexpression,the glutamine uptake and glutamate production in Eca109 and KYSE150 cells increased significantly(glutamine uptake:t = 5. 803 and 56. 13,respectively,each P < 0. 01;glutamate production:t = 11. 06 and 4. 695,respectively,each P < 0. 01). After METTL3 knockdown,the expression levels of glutamine metabolism related proteins ASCT2,GLS and GLUD1 in Eca109 and KYSE150 cells were significantly down-regulated,while after METTL3 overexpression,the expression levels of ASCT2,GLS and GLUD1 were significantly up-regulated.Conclusion METTL3 is highly expressed in esophageal cancer and may promote cell proliferation by mediating glutamine metabolism in esophageal cancer cells.

Study on the Role and Mechanism of METTL3 Mediating the Up-regulation of m6A Modified Long Non-coding RNA THAP7-AS1 in Promoting the Occurrence of Lung Cancer / 中国肺癌杂志

BACKGROUND@#Lung cancer is a major threat to human health. The molecular mechanisms related to the occurrence and development of lung cancer are complex and poorly known. Exploring molecular markers related to the development of lung cancer is helpful to improve the effect of early diagnosis and treatment. Long non-coding RNA (lncRNA) THAP7-AS1 is known to be highly expressed in gastric cancer, but has been less studied in other cancers. The aim of the study is to explore the role and mechanism of methyltransferase-like 3 (METTL3) mediated up-regulation of N6-methyladenosine (m6A) modified lncRNA THAP7-AS1 expression in promoting the development of lung cancer.@*METHODS@#Samples of 120 lung cancer and corresponding paracancerous tissues were collected. LncRNA microarrays were used to analyze differentially expressed lncRNAs. THAP7-AS1 levels were detected in lung cancer, adjacent normal tissues and lung cancer cell lines by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The diagnostic value of THAP7-AS1 in lung cancer and the relationship between THAP7-AS1 expression and survival rate and clinicopathological parameters were analyzed. Bioinformatics analysis, methylated RNA immunoprecipitation (meRIP), RNA pull-down and RNA-immunoprecipitation (RIP) assay were used to investigate the molecular regulation mechanism of THAP7-AS1. Cell proliferation, migration, invasion and tumorigenesis of SPC-A-1 and NCI-H1299 cells were determined by MTS, colony-formation, scratch, Transwell and xenotransplantation in vivo, respectively. Expression levels of phosphoinositide 3-kinase/protein kenase B (PI3K/AKT) signal pathway related protein were detected by Western blot.@*RESULTS@#Expression levels of THAP7-AS1 were higher in lung cancer tissues and cell lines (P<0.05). THAP7-AS1 has certain diagnostic value in lung cancer [area under the curve (AUC)=0.737], and its expression associated with overall survival rate, tumor size, tumor-node-metastasis (TNM) stage and lymph node metastasis (P<0.05). METTL3-mediated m6A modification enhanced THAP7-AS1 expression. The cell proliferation, migration, invasion and the volume and mass of transplanted tumor were all higher in the THAP7-AS1 group compared with the NC group and sh-NC group of SPC-A-1 and NCI-H1299 cells, while the cell proliferation, migration and invasion were lower in the sh-THAP7-AS1 group (P<0.05). THAP7-AS1 binds specifically to Cullin 4B (CUL4B). The cell proliferation, migration, invasion, and expression levels of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), phosphoinositide-3 kinase, catalytic subunit delta (PIK3CD), phospho-phosphatidylinositol 3-kinase (p-PI3K), phospho-protein kinase B (p-AKT) and phospho-mammalian target of rapamycin (p-mTOR) were higher in the THAP7-AS1 group compared with the Vector group of SPC-A-1 and NCI-H1299 cells (P<0.05).@*CONCLUSIONS@#LncRNA THAP7-AS1 is stably expressed through m6A modification mediated by METTL3, and combines with CUL4B to activate PI3K/AKT signal pathway, which promotes the occurrence and development of lung cancer.

METTL3 promotes proliferation , migration , and secretion of inflammatory factors by mRNA m6A methylation in rheumatoid arthritis synovial fibroblasts / 安徽医科大学学报

Objective @#To investigate the effect and mechanism of methyltransferase-like 3 (METTL3) on the pro- liferation , migration , and secretion of inflammatory factors by synovial fibroblasts from rheumatoid arthritis (RA) .@*Methods @#The expression of METTL3 in synovial tissue (SF) from 25 patients with rheumatoid arthritis and 25 pa- tients with osteoarthritis was detected by RT-qPCR and immunohistochemistry , respectively . The concentration of RNA m6A was detected by ELISA . RA synovial fibroblasts were isolated and cultured , and divided into NC ( nor- mal control) group , hi-METTL3 (overexpression of METTL3) group , si-METTL3 (knock-down METTL3) group , and STM2457 (METTL3 specific inhibitor) intervention group . Cell proliferation was detected by CCK-8 method . Apoptosis was detected by flow cytometry . And the concentrations of interleukin-6 ( IL-6) , interleukin-17A ( IL- 17A) , receptor activator of nuclear factor-kappa B ligand (RANKL) , and osteoprotegerin (OPG) in the superna- tant of cell culture were detected by ELISA . @*Results @#Compared with synovial tissue of osteoarthritis , the expres- sion of mRNA m6A and METTL3 in synovial tissue of RA significantly increased (P < 0. 05) . After overexpression of METTL3 , the expression of m6A in synovial fibroblasts increased . The proliferation and migration abilities of SF in hi-METTL3 group were significantly improved , and their apoptosis did not change significantly . The secretion of cytokines IL-6 and RANKL of SF in hi-METTL3 group significantly increased , while the OPG significantly de- creased (P < 0. 05) . After interfering with METTL3 expression , the expression of m6A in synovial fibroblasts de- creased . Cell proliferation and migration of SF in siMETTL3 group significantly decreased . The secretion of cyto- kines IL-6 and RANKL significantly decreased , and OPG significantly increased ( P < 0. 05) . After intervention with METTL3 inhibitor STM2457 , the proliferation and migration of synovial fibroblasts were significantly reduced , and the secretion of cytokines IL-6 and RANKL significantly reduced , and OPG significantly increased ( P < 0. 05) . There was no significant difference in the expression of IL-17A among each group . @*Conclusion @#METTL3 may promote the proliferation and migration of RA synovial fibroblasts , enhance the expression of IL-6 and RANKL , and inhibit the expression of OPG through RNA m6A methylation modification .

Methyltransferase-like 3-mediated N6-methyladenosine methylation modification regulates the biological activity of vascular endothelial cells via the Notch pathway / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the role and mechanism of methyltransferase-like 3(METTL3)-mediated N6-methyladenosine(m6A)methylation modification in regulating biological activity of vascular endothelial cells in the pathogenesis of choroidal neovascularization.METHODS: Human umbilical vein endothelial cells(HUVEC)cultured in vitro were divided into the following groups: control group(normal culture), low density lipoprotein(LDL)group, fluorescence-labelled LDL(Dil-LDL)group, 12.5μg/mL and 25μg/mL oxidized LDL(ox-LDL)groups, 12.5μg/mL and 25μg/mL fluorescence-labelled ox-LDL(Dil-ox-LDL)groups, DMSO group, STM2457(METTL3 inhibitor)group, DAPT group; and monkey retina-choroidal endothelial cells(RF/6A)cultured in vitro were divided into control group, DMSO group, 12.5 μg/mL ox-LDL group, and DAPT group. Endocytosed lipoprotein level was examined through fluorescence microscopy. RNA m6A methylation level was detected through a dot blot assay. Protein and RNA levels of METTL3 or angiogenesis-related markers were measured through Western blot assays and real-time quantitative polymerase chain reaction(RT-qPCR), respectively. METTL3 expression and localization were investigated through immunofluorescence. Cell migratory and tube formation capacities were assessed through transwell migration and tube formation assays, respectively.RESULTS: Endocytosed lipoprotein levels in HUVECs exposed to Dil-LDL, 12.5μg/mL and 25μg/mL Dil-ox-LDL groups were significantly higher than those in the control group. 12.5μg/mL and 25μg/mL ox-LDL groups significantly increased m6A methylation(all P&#x003C;0.05), METTL3 protein expression(all P&#x003C;0.01), and cell migration and angiogenesis capacities(all P&#x003C;0.01). METTL3 mRNA level was significantly unregulated in the 12.5μg/mL ox-LDL group(P&#x003C;0.05). In comparison to the DMSO group, the addition of STM2457 caused significant decrease in m6A methylation level(P&#x003C;0.05), expression of VEGF and other angiogenesis-related markers(all P&#x003C;0.05), cell migration and angiogenesis capacities(all P&#x003C;0.01)and the expression of NICD(P&#x003C;0.05). However, there were no significant differences in METTL3 protein and mRNA levels(all P&#x003E;0.05). The expression of VEGF and NICD(all P&#x003C;0.05), as well as the ability of cell migration and angiogenesis of RF/6A, was all significantly decreased in the DAPT group compared to the DMSO group(all P&#x003C;0.01).CONCLUSION: METTL3-mediated m6A methylation modification promotes angiogenesis in vascular endothelial cells via the Notch signaling pathway in the pathogenesis of choroidal neovascularization.

Inhibitory Effect and Mechanism of Sishenwan-containing Serum on Aerobic Glycolysis in Human Colon Cancer Cells / 中国实验方剂学杂志

ObjectiveTo explore the effect and mechanism of Sishenwan-containing serum on aerobic glycolysis in human colon cancer HCT116 cells. MethodCell counting kit-8 （CCK-8） was used to detect the cell viability of colon cancer HCT116 cells after treatment with Sishenwan-containing serum （2.5%， 5%， and 10%） for 24， 48， 72 h. The concentration of lactic acid， the content of intracellular glucose， and the activity of hexokinase （HK） and fructose-6-phosphate kinase （PFK） in the cell culture medium were detected by the micro-method. The content of glucose transporter 1 （GluT1） mRNA was detected by Real-time quantitative polymerase chain reaction （Real-time PCR）. The protein expression of GluT1 and methyltransferase-like 3 （MettL3） was detected by Western blot. The expression of GluT1 in cells was detected by immunofluorescence and the level of N6-methyladenosine （m6A） RNA methylation was detected by colorimetry. ResultCompared with the normal serum， 2.5%， 5%， and 10% Sishenwan-containing serum had no significant effect on the viability of HCT116 cells at 24 h， while 10% Sishenwan-containing serum showed a significant inhibitory effect on the viability of HCT116 cells at 48 h （P<0.05）. Hence， 10% Sishenwan-containing serum was used in subsequent experiments， and the intervention time was 48 h. Compared with the normal serum， 10% Sishenwan-containing serum could reduce lactate production （P<0.05）， down-regulate glucose uptake （P<0.05）， and blunt the activities of HK and PFK， the key rate-limiting enzymes of glycolysis （P<0.05）. Meanwhile， 10% Sishenwan-containing serum could decrease the expression of GluT1 protein （P<0.01） and mRNA （P<0.05） and reduce the proportion of cells expressing GluT1 （P<0.01）. Compared with the normal serum， Sishenwan-containing serum also decreased the protein content of MettL3 （P<0.05） and the methylation level of m6A RNA （P<0.01）. ConclusionSishenwan can inhibit glycolysis in colon cancer cells， and its inhibitory mechanism may be related to reducing MettL3 overexpression， inhibiting m6A RNA methylation， and down-regulating GluT1 and the activities of intracellular aerobic glycolysis-related enzymes such as HK and PFK.

Mechanism of berberine inhibiting invasion and migration of renal carcinoma cells by down-regulating the expression of METTL3 / 中国药房

OBJECTIVE To investigate the inhibitory effect of berberine （BER） on the invasion and migration of human renal carcinoma cells and its potential mechanism. METHODS Using human renal carcinoma OSRC-2 cell as object， alamarBlue assay was adopted to detect the inhibitory effects of 0 （control group）， 25， 50， 75， 100， 125， 150， 175 and 200 μmol/L BER on the proliferation of OSRC-2 cell after treatment for 24 h and 48 h. After treated with 0（control group）， 50， 100 μmol/L BER for 48 h， the effect of BER on cell cycle was analyzed by flow cytometry. The migration of OSRC-2 cells in 24 h and 36 h was observed by cell scratch test， and the invasion ability of OSRC-2 cells in 24 h was detected by Transwell assay. The protein expression of methyltransferase-like 3 （METTL3） was detected by Western blot after treatment for 48 h， and RNA methylation quantification kit was used to detect the levels of N6-methyladenosine （m6A） in OSRC-2 cells. RESULTS Compared with control group， BER at different concentrations could significantly decrease the survival rate of OSRC-2 cells （P＜0.01）， and showed a dose-dependent and time-dependent manner. After 48 h of BER treatment at 50， 100 μmol/L， the cell was arrested in G0/G1 phase （P＜0.01）. Compared with control group， the migration and invasion abilities of cells in 50， 100 μmol/L BER group were significantly decreased （P＜0.05 or P＜0.01）； the protein expression of METTL3 and the level of m6A in RNA were significantly decreased （P＜0.01）. CONCLUSIONS BER can inhibit level of m6A by down-regulating the expression of METTL3， thereby inhibiting the invasion and metastasis of human renal carcinoma cells.

lncRNA THAP7-AS1 affects the glycolysis of gastric cancer cells by regulating METTL3 mediated m6A modification / 肿瘤

Objective:To explore the effect of long noncoding RNA(lncRNA)THAP7-AS1 on the glycolysis of gastric cancer(GC)cells by regulating methyltransferase-like 3(METTL3)mediated N6-methyladenosine(m6A)modification. Methods:Gene Expression Profiling Interactive Analysis(GEPIA)database was used to analyze the expression levels of THAP7-AS1 and METTL3 in GC tissues and their relationship with the overall survival of GC patients.Real-time fluorescence quantitative PCR and Western blotting were used to analyze the expression of THAP7-AS1,METTL3 mRNA,glucose transporter 1(GLUT1)mRNA,and METTL3 protein in GC tissues and paracancerous tissues samples collected from 80 GC patients in Department of Oncology,The Third Affiliated Hospital of Zunyi Medical University(the First People's Hospital of Zunyi),and the relationship between THAP7-AS1 levels and the clinicopathological characteristics of GC patients was analyzed.Real-time fluorescence quantitative PCR and Western blotting were used to verify the expression of THAP7-AS1,METTL3 mRNA,GLUT1 mRNA,and METTL3 protein in GES-1,BGC-823 and SGC-7901 cells.Lentiviral infection was used to knock-down THAP7-AS1 or overexpress METTL3 BGC-823 and SGC-7901 cells,and real-time fluorescence quantitative PCR and Western blotting were used to examine effect of different treatment on the expression of THAP7-AS1,METTL3 mRNA,GLUT1 mRNA,and METTL3 protein;colorimetry assay was used to detect the m6A modification level in the total RNA;methylated RNA immunoprecipitation(MeRIP)-quantitative PCR(qPCR)was used to detect the GLUT1 m6A modification level;glycolysis stress test kits were used to detect the extracellular acidification rate(ECAR),glucose uptake and lactate production of treated GC cells;Western blotting was used to examine the expression levels of METTL3,GLUT1,M2 type pyruvate kinase(PKM2)and lactic dehydrogenase(LDHA)proteins in treated GC cells;EdU staining,wound healing assay and Transwell invasion assay were used to evaluate the proliferation,migration and invasion of treated GC cells.Finally,a mouse model of subcutaneously transplanted GC tumor was established using nude mice,and the effect of knocking-down THAP7-AS1 was assessed by measuring the tumor volume and weight,as well as the expression levels of METTL3 and GLUT1 proteins in transplanted GC tumor tissues. Results:Analysis of the GEPIA database showed that the expression levels of THAP7-AS1 and METTL3 was higher in GC tissue than those in normal gastric tissues,and the expression levels of THAP7-AS1 and METTL3 are negatively correlated with overall survival of GC patients(P＜0.05).Compared with the paracancerous tissues(or normal gastric epithelial cells),the expression levels of THAP7-AS1,METTL3 mRNA,GLUT1 mRNA and METTL3 protein was significantly increased in GC tissues(or GC cells),and the higher the expression of THAP7-AS1,the higher the TNM stage,the lower the degree of tumor differentiation,and the easier the occurrence of microvascular infiltration and lymph node metastasis(P＜0.05).Knocking-down of THAP7-AS1 down-regulated the expression levels of METTL3 mRNA,GLUT1 mRNA and METTL3 protein,the m6A modification levels in total RNA and GLUT1,the ECAR levels,the glucose uptake,the lactate production,EdU positive rate,scratch healing rate,the number of invaded cells,and the expression levels of glycolysis-related proteins(METTL3,GLUT1,PKM2 and LDHA)in GC cells(P＜0.05).Overexpression of METTL3 could partially reverse these effects of THAP7-AS1 knock-down(P＜0.05).In vivo experiments showed that THAP7-AS1 knock-down can obviously inhibit the growth of transplanted GC tumors(P＜0.05). Conclusion:lncRNA THAP7-AS1 can promote the glycolysis which further promotes the proliferation,migration and invasion of GC cells by regulating METTL3 mediated m6A modification.

Changes of mRNA N6-methyladenosine methylation in blood of patients with Alzheimer's disease / 中华行为医学与脑科学杂志

Objective:To explore the changes of mRNA N6-methyladenosine methylation level and methyltransferase-like 3 (METTL3) and demethylase fat mass and obesity-associated (FTO) in the blood of patients with Alzheimer's disease (AD) compared with normal controls.Methods:From January 2020 to June 2021, totally 40 AD patients treated in the outpatient and inpatient department of Neurology of the Affiliated Hospital of Jining Medical University were selected as the patient group, and 40 healthy volunteers as the control group. The blood samples were collected to extract plasma and peripheral blood mononuclear cells for enzyme-linked immunosorbent assay (ELISA), Western blot (WB), quantitative real-time PCR (qPCR) and m6A methylation quantification experiments respectively to detect the methylation levels of METTL3, FTO and m6A. The data were analyzed by SPSS 23.0 statistical software for t-test. Results:The plasma concentrations of METTL3 and FTO protein in AD group were lower than those in control group (METTL3: (22.33±3.01)ng/mL, (25.63±1.70)ng/mL, t=6.055, P<0.01; FTO: (63.51±4.95)pg/mL, (69.60±4.60)pg/mL, ( t=5.704, P<0.01). The band gray values of METTL3 and FTO protein in blood cells in AD group were lower than those in control group (METTL3: 0.399 5±0.028 7, 0.676 6±0.053 3, t=7.935, P=0.001; FTO: 0.439 4±0.017 8, 0.782 6±0.087 6, t=6.652, P=0.003). The expression levels of METTL3 and FTO in blood cell RNA in AD group were lower than those in control group (METTL3: 0.387 8±0.020 3, 1.010 0±0.177 0, t=6.041, P=0.004; FTO: 0.442 8±0.037 1, 1.003 0±0.090 4, t=9.931, P=0.001). The levels of m6A in blood cell RNA in AD group were lower than those in control group((0.000 571±0.000 167)%, (0.002 514±0.001 284)%, t=6.041, P=0.004). Conclusion:The levels of METL3, FTO and m6A methylation are down-regulated in the plasma and peripheral blood mononuclear cells of patients with AD, indicating that there is a certain association between mRNA N6-methyladenosine methylation and AD.

Expression and prognostic value of glycolytic metabolism related protein methyltransferase-like 3 in resectable primary liver cancer / 中国医师进修杂志

Objective:To investigate the expression and prognostic value of glycolytic metabolism related methyltransferase-like 3 (METTL3) in resectable primary liver cancer.Methods:The METTL3 mRNA expression data, clinicopathological data and prognostic information of 364 patients with primary liver cancer and 50 healthy normal liver tissues were downloaded from the Cancer Genome Atlas (TCGA) database, and gene set enrichment analysis was performed. Then the tissue samples of 239 patients with primary liver cancer who underwent radical hepatectomy in Chongqing Armed Police Corps Hospital from January 2016 to may 2019 were selected. Among them, 110 cases contained matched normal liver tissue adjacent to the cancer. The expression of METTL3 protein was detected by immunohistochemical staining. Kaplan-Meier survival curve was drawn, and log-rank test was used for comparison; Cox proportional hazard model was used to evaluate the risk factors affecting the prognosis in patients with primary liver cancer.Results:TCGA database analysis result showed that the expression level of METTL3 mRNA in liver cancer tissue was significantly higher than that in normal liver tissue: 3.72 (3.19, 4.03) vs. 2.45 (2.11, 2.68), and there was statistical difference ( P = 0.007); Kaplan-Meier survival curve analysis result showed that the median overall survival time and disease-free survival time in patients with high expression of METTL3 mRNA were significantly shorter than those in patients with low expression of METTL3 mRNA (43.0 months vs. 72.0 months and 22.0 months vs. 38.0 months, HR = 1.7 and 1.4, P = 0.002 and 0.024). Gene set enrichment analysis result showed that METTL3 mRNA was related to impaired glucose metabolism. In the clinical sample study, the positive expression rate of METTL3 protein in liver cancer tissue was significantly higher than that in normal liver tissue adjacent to cancer: 54.55% (60/110) vs. 14.55% (16/110), and there was statistical difference ( χ2 = 38.92, P<0.01). Among 239 patients with primary liver cancer, 132 cases (55.23%) had positive expression of METTL3 protein in liver cancer tissue, and 107 cases had negative expression. Compared with METTL3 protein negative patients, METTL3 protein positive patients had higher body mass index; higher TNM stage, BCLC stage and tissue grade; more lesions; larger tumor sizes; more common satellite nodules; higher leukocyte count, platelet count and neutrophil count, and there were statistical differences ( P<0.05 or <0.01). Kaplan-Meier survival curve analysis result showed that the median overall survival time and disease-free survival time in patients with METTL3 protein positive were significantly shorter than those in patients with METTL3 negative (18.0 months vs. 38.0 months and 13.0 months vs. 27.0 months, P<0.01). Univariate and multivariate Cox analysis result showed that METTL3 protein positive in liver cancer tissue was an independent risk factor affecting overall survival time and disease-free survival time ( HR = 1.840 and 2.096, 95% CI 1.298 to 2.608 and 1.469 to 2.991, P<0.01). Conclusions:METTL3 is involved in glycolytic metabolism of primary liver cancer, and can be used as a promising biomarker to evaluate the prognosis of patients with primary liver cancer.