1.C/EBPβ-Lin28a positive feedback loop triggered by C/EBPβ hypomethylation enhances the proliferation and migration of vascular smooth muscle cells in restenosis.
Xiaojun ZHOU ; Shan JIANG ; Siyi GUO ; Shuai YAO ; Qiqi SHENG ; Qian ZHANG ; Jianjun DONG ; Lin LIAO
Chinese Medical Journal 2025;138(4):419-429
BACKGROUND:
The main cause of restenosis after percutaneous transluminal angioplasty (PTA) is the excessive proliferation and migration of vascular smooth muscle cells (VSMCs). Lin28a has been reported to play critical regulatory roles in this process. However, whether CCAAT/enhancer-binding proteins β (C/EBPβ) binds to the Lin28a promoter and drives the progression of restenosis has not been clarified. Therefore, in the present study, we aim to clarify the role of C/EBPβ-Lin28a axis in restenosis.
METHODS:
Restenosis and atherosclerosis rat models of type 2 diabetes ( n = 20, for each group) were established by subjecting to PTA. Subsequently, the difference in DNA methylation status and expression of C/EBPβ between the two groups were assessed. EdU, Transwell, and rescue assays were performed to assess the effect of C/EBPβ on the proliferation and migration of VSMCs. DNA methylation status was further assessed using Methyltarget sequencing. The interaction between Lin28a and ten-eleven translocation 1 (TET1) was analysed using co-immunoprecipitation (Co-IP) assay. Student's t -test and one-way analysis of variance were used for statistical analysis.
RESULTS:
C/EBPβ expression was upregulated and accompanied by hypomethylation of its promoter in restenosis when compared with atherosclerosis. In vitroC/EBPβ overexpression facilitated the proliferation and migration of VSMCs and was associated with increased Lin28a expression. Conversely, C/EBPβ knockdown resulted in the opposite effects. Chromatin immunoprecipitation assays further demonstrated that C/EBPβ could directly bind to Lin28a promoter. Increased C/EBPβ expression and enhanced proliferation and migration of VSMCs were observed after decitabine treatment. Further, mechanical stretch promoted C/EBPβ and Lin28a expression accompanied by C/EBPβ hypomethylation. Additionally, Lin28a overexpression reduced C/EBPβ methylation via recruiting TET1 and enhanced C/EBPβ-mediated proliferation and migration of VSMCs. The opposite was noted in Lin28a knockdown cells.
CONCLUSION
Our findings suggest that the C/EBPβ-Lin28a axis is a driver of restenosis progression, and presents a promising therapeutic target for restenosis.
Animals
;
Cell Proliferation/genetics*
;
Cell Movement/genetics*
;
Muscle, Smooth, Vascular/metabolism*
;
Rats
;
DNA Methylation/physiology*
;
CCAAT-Enhancer-Binding Protein-beta/genetics*
;
Male
;
Myocytes, Smooth Muscle/cytology*
;
Rats, Sprague-Dawley
;
RNA-Binding Proteins/genetics*
;
Cells, Cultured
;
Coronary Restenosis/metabolism*
2.Correlation analysis of low expression of LY86-AS1 and KHDRBS2 with immune cell invasion and prognosis in glioblastoma.
Shasha WANG ; Wenhao ZHAO ; Xining HE ; Yangyang ZHANG ; Wenli CHANG
Chinese Journal of Cellular and Molecular Immunology 2025;41(3):245-253
Objective To investigate the expression and correlation of LY86-AS1 and KHDRBS2 in glioblastoma (GBM), and their impacts on the prognosis of patients and immune cell infiltration. Methods Based on the GSE50161 dataset from the Gene Expression Omnibus (GEO) database, LY86-AS1 and KHDRBS2, which are closely related to the development of GBM, were identified by WGCNA and differential expression analysis. The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases were used to analyze the relationship between the expression of LY86-AS1 and KHDRBS2 and the prognosis of GBM patients. Multiple datasets were employed to analyze the correlation between the expression levels of LY86-AS1 and KHDRBS2 and its relationship with immune cell infiltration. Real-time quantitative PCR was used to verify the expression of LY86-AS1 and KHDRBS2 in GBM and normal brain tissues. The Human Protein Atlas (HPA) database was accessed to obtain the protein expression of KHDRBS2, and immunohistochemical staining was conducted to verify the protein expression of KHDRBS2. Results LY86-AS1 and KHDRBS2 were lowly expressed in GBM tissues and were closely related to the development of GBM, showing a significant positive correlation. Patients with low expression levels of LY86-AS1 and KHDRBS2 had a lower overall survival rate than those with high expression levels. LY86-AS1 was positively correlated with naive B cells, plasma cells, activated NK cells, M1 macrophages, activated mast cells and monocytes. KHDRBS2 was positively correlated with naive B cells, plasma cells, helper T cells, activated NK cells and monocytes. Conclusion The low expression levels of LY86-AS1 and KHDRBS2 in GBM, which is associated with poor prognosis, affect the tumor immune microenvironment and may serve as potential new biomarkers for the diagnosis of GBM and the prognosis assessment of patients.
Humans
;
Glioblastoma/metabolism*
;
Prognosis
;
Brain Neoplasms/pathology*
;
Gene Expression Regulation, Neoplastic
;
RNA-Binding Proteins/metabolism*
3.Research progress on phenotypic modifier genes in spinal muscular atrophy.
Chinese Journal of Contemporary Pediatrics 2025;27(2):229-235
Spinal muscular atrophy (SMA) is a common fatal autosomal recessive genetic disorder in childhood, primarily caused by homozygous deletion of the <i>SMN1i> gene. Its main characteristics include the degenerative changes in the anterior horn motor neurons of the spinal cord, leading to symmetrical progressive muscle weakness and atrophy of the proximal limbs. However, SMA patients with the same genetic background often exhibit different degrees of disease severity. In addition to the well-established modifier gene <i>SMN2i>, the effect of other modifier genes on clinical phenotypes should not be overlooked. This paper reviews the latest advancements in the pathogenic and modifier genes of SMA, aiming to provide a deeper understanding of the pathogenic mechanisms and phenotypic differences in SMA, as well as to offer new strategies and targets for treating this condition.
Humans
;
Muscular Atrophy, Spinal/genetics*
;
Phenotype
;
Survival of Motor Neuron 1 Protein/genetics*
;
Genes, Modifier
;
Survival of Motor Neuron 2 Protein/genetics*
4.Analysis of <i>SRSF2i> Gene Mutation in Patients with Chronic Myelomonocytic Leukemia.
Chang-Rui TAO ; Bi-Tao XIAO ; Pin WU ; Zhi-Qi WANG ; Hong-Ying CHAO
Journal of Experimental Hematology 2025;33(1):20-24
OBJECTIVE:
To characterize the occurrence of <i>SRSF2i> mutations in chronic myelomonocytic leukemia(CMML) patients and their correlation with other gene mutations and some clinical characteristics.
METHODS:
The clinical data of 43 CMML patients diagnosed in Changzhou No.2 People's Hospital and Wuxi No.2 People's Hospital were retrospectively analyzed, and gene mutations detection was performed using next-generation sequencing (NGS).
RESULTS:
Among the 43 CMML patients the <i>SRSF2i> mutation detection rate was 39.5%(17/43). These mutations clustered collectively at the proline 95 residue in the splicing factor <i>SRSF2i>. The other genes with mutation rate greater than 15% were <i>ASXL1i> (48.8%), <i>TET2i> (41.9%), <i>NRASi> (30.2%), <i>RUNX1i> (25.6%), and <i>SETBP1i> (16.3%). Among <i>SRSF2i>- mutated patients, the most common co-mutation was <i>ASXL1i>, followed by <i>TET2i>. The median age of <i>SRSF2i> mutant patients was significantly higher than that of the wild type (68 <i>vsi> 51.5, <i>Pi> < 0.001), but there was not statistically significant differences in gender, peripheral leukocytes, hemoglobin, platelets, karyotype, and blast cell compared to the wild-type (all <i>Pi> >0.05). Notably, 4 out of the 6 <i>SRSF2i> mut<i>ASXL1i>mut CMML patients developed leukemia transformation, and 1 out of 10 <i>SRSF2i> wt<i>ASXL1i>wt CMML patients developed leukemia transformation, with statistically significant difference in leukemia transformation rates (66.7% <i>vsi> 10%, <i>Pi> =0.036).
CONCLUSION
<i>SRSF2i> mutations have a high incidence in CMML, occurring frequently in older patients, and often coexisting with <i>ASXL1i> and <i>TET2i> mutations. Patients with CMML carrying both <i>SRSF2i>mut <i>ASXL1i>mut double mutations have a higher risk of acute leukemia transformation.
Humans
;
Serine-Arginine Splicing Factors/genetics*
;
Mutation
;
Leukemia, Myelomonocytic, Chronic/genetics*
;
Retrospective Studies
;
Male
;
Female
;
Repressor Proteins/genetics*
;
DNA-Binding Proteins/genetics*
;
Dioxygenases
;
Middle Aged
;
Aged
;
Proto-Oncogene Proteins/genetics*
5.Characterization of Acute Myeloid Leukemia Patients with <i>DEK-NUP214i> Fusion Gene Positive.
Ran HUANG ; Yuan-Bing WU ; Ya-Xue WU ; Xiao-Hui HU
Journal of Experimental Hematology 2025;33(5):1293-1298
OBJECTIVE:
To analyze the clinical features of acute myeloid leukemia patients with <i>DEK-NUP214i> fusion gene positive.
METHODS:
The <i>DEK-NUP214i> fusion gene was amplified by multi-nested PCR in 26 patients admitted to the First Affiliated Hospital of Soochow University from January 2018 to October 2023, and the disease course and post-transplant survival data were obtained by searching outpatient and inpatient medical records and telephone follow-up.
RESULTS:
The median follow-up time of pateints was 21.25(0.9-60.2) months. Among 26 patients with <i>DEK-NUP214i> fusion gene positive AML, 15 patients had <i>FLT3-ITDi> gene mutation positive. One patient died after abandoning treatment due to non-remission of induction chemotherapy, one died due to infection, and 23 patients received allo-HSCT after achieving CR, of which one patient died within one month after transplantation due to multiple infections and one died due to severe pulmonary infection that did not respond to treatment. One patient received allo-HSCT in non-remission state and later died due to recurrence.
CONCLUSION
<i>DEK-NUP214i> fusion gene positive AML is a type of acute leukemia subtype with high risk and poor prognosis. Allo-HSCT treatment at the early stage of disease remission is the most effective way to improve the prognosis of patients.
Humans
;
Leukemia, Myeloid, Acute/genetics*
;
Poly-ADP-Ribose Binding Proteins
;
Oncogene Proteins, Fusion/genetics*
;
Nuclear Pore Complex Proteins/genetics*
;
Oncogene Proteins/genetics*
;
Chromosomal Proteins, Non-Histone/genetics*
;
Male
;
Female
;
Adult
;
Mutation
;
Hematopoietic Stem Cell Transplantation
;
Middle Aged
6.Effects of Down-regulation of NCL Expression on the Biological Behavior of Acute Myeloid Leukemia Kasumi-1 Cells.
Hui-Li LIU ; Wen-Xin XU ; Yang-Yan CAI ; Hong-Mei LI
Journal of Experimental Hematology 2025;33(5):1312-1317
OBJECTIVE:
To investigate the role of nucleolin (NCL) in acute myeloid leukemia (AML) Kasumi-1 cells and its underlying mechanism.
METHODS:
The Kasumi-1 cells were infected with lentivirus carrying shRNA to downregulate NCL expression. Cell proliferation was detected by CCK-8 assay, and cell apoptosis and cell cycle were determined by flow cytometry. Transcriptome next-generation sequencing (NGS) was performed to predict associated signaling pathways, the expression levels of related genes were measured by RT-PCR.
RESULTS:
Down-regulation of NCL expression significantly inhibited the proliferation of Kasumi-1 cells (<i>Pi> <0.01) and markedly increased the apoptosis rate (<i>Pi> <0.001). Cell cycle analysis showed significant changes in the distribution of cells in the G1 and S phases after NCL knockdown (<i>Pi> <0.05), while no significant difference was observed in the G2 phase (<i>Pi> >0.05). Transcriptome sequencing analysis demonstrated that differentially expressed genes in Kasumi-1 cells with low expression of NCL were primarily enriched in key signaling pathways, including ribosome, spliceosome, RNA transport, cell cycle, and amino acid biosynthesis. qPCR validation showed that the expression of <i>BAX, CASP3, CYCS, PMAIP1, TP53i> , and <i>CDKN1Ai> was significantly upregulated after NCL downregulation (<i>Pi> <0.05), with <i>CDKN1Ai> exhibiting the most pronounced difference.
CONCLUSION
NCL plays a critical role in regulating the proliferation, apoptosis, and cell cycle progression of Kasumi-1 cells. The mechanism likely involves suppressing cell cycle progression through activation of the TP53-CDKN1A pathway and promoting apoptosis by upregulating apoptosis-related genes.
Humans
;
Leukemia, Myeloid, Acute/pathology*
;
Down-Regulation
;
Cell Proliferation
;
Apoptosis
;
RNA-Binding Proteins/genetics*
;
Nucleolin
;
Cell Line, Tumor
;
Phosphoproteins/metabolism*
;
Cell Cycle
;
Signal Transduction
;
RNA, Small Interfering
7.ADAR1 Regulates the ERK/c-FOS/MMP-9 Pathway to Drive the Proliferation and Migration of Non-small Cell Lung Cancer Cells.
Li ZHANG ; Xue PAN ; Wenqing YAN ; Shuilian ZHANG ; Chiyu MA ; Chenpeng LI ; Kexin ZHU ; Nijia LI ; Zizhong YOU ; Xueying ZHONG ; Zhi XIE ; Zhiyi LV ; Weibang GUO ; Yu CHEN ; Danxia LU ; Xuchao ZHANG
Chinese Journal of Lung Cancer 2025;28(9):647-657
BACKGROUND:
Double-stranded RNA-specific adenosine deaminase 1 (ADAR1) binds to double-stranded RNA and catalyzes the deamination of adenosine (A) to inosine (I). The functional mechanism of ADAR1 in non-small cell lung cancer (NSCLC) remains incompletely understood. This study aimed to investigate the prognostic significance of ADAR1 in NSCLC and to elucidate its potential role in regulating tumor cell proliferation and migration.
METHODS:
Data from The Cancer Genome Atlas (TCGA) and cBioPortal were analyzed to assess the correlation between high ADAR1 expression and clinicopathological features as well as prognosis in lung cancer. We performed Western blot (WB), cell proliferation assays, Transwell invasion/migration assays, and nude mouse xenograft modeling to examine the phenotypic changes and molecular mechanisms induced by ADAR1 knockdown. Furthermore, the ADAR1 p150 overexpression model was utilized to validate the proposed mechanism.
RESULTS:
ADAR1 expression was significantly elevated in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) tissues compared with adjacent non-tumor tissues (LUAD: P=3.70×10-15, LUSC: P=0.016). High ADAR1 expression was associated with poor prognosis (LUAD: P=2.03×10-2, LUSC: P=2.81×10-2) and distant metastasis (P=0.003). Gene Set Enrichment Analysis (GSEA) indicated that elevated ADAR1 was associated with mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway activation, matrix metalloproteinase-9 (MMP-9) expression, and cell adhesion. ADAR1 and MMP-9 levels showed a strongly positive correlation (P=6.45×10-34) in 10 lung cancer cell lines, highest in H1581. Knockdown of ADAR1 in H1581 cells induced a rounded cellular morphology with reduced pseudopodia. Concomitantly, it suppressed cell proliferation, invasion, migration, and in vivo tumorigenesis. It also suppressed ERK phosphorylation and downregulated cellular Finkel-Biskis-Jinkins murine osteosarcoma viral oncogene homolog (c-FOS), MMP-9, N-cadherin, and Vimentin. Conversely, ADAR1 p150 overexpression in PC9 cells enhanced ERK phosphorylation and increased c-FOS and MMP-9 expression.
CONCLUSIONS
High ADAR1 expression is closely associated with poor prognosis and distant metastasis in NSCLC patients. Mechanistically, ADAR1 may promote proliferation, invasion, migration, and tumorigenesis in lung cancer cells via the ERK/c-FOS/MMP-9 axis.
Humans
;
Lung Neoplasms/physiopathology*
;
Adenosine Deaminase/genetics*
;
Matrix Metalloproteinase 9/genetics*
;
Cell Proliferation
;
Carcinoma, Non-Small-Cell Lung/physiopathology*
;
Cell Movement
;
Animals
;
Mice
;
RNA-Binding Proteins/genetics*
;
Female
;
Male
;
Cell Line, Tumor
;
Proto-Oncogene Proteins c-fos/genetics*
;
Middle Aged
;
MAP Kinase Signaling System
;
Gene Expression Regulation, Neoplastic
;
Mice, Nude
;
Extracellular Signal-Regulated MAP Kinases/genetics*
8.Knockdown of <i>NPTX1i> promotes osteogenic differentiation of human bone marrow mesenchymal stem cells.
Ting SHUAI ; Yanyan GUO ; Chunping LIN ; Xiaomei HOU ; Chanyuan JIN
Journal of Peking University(Health Sciences) 2025;57(1):7-12
OBJECTIVE:
To initially investigate the function of neuronal pentraxin 1 (<i>NPTX1i>) gene on osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs).
METHODS:
hBMSCs were induced to undergo osteogenic differentiation, and then RNA was collected at different time points, namely 0, 3, 7, 10 and 14 d. The mRNA expression levels of key genes related with osteogenic differentiation, including runt-related transcription factor 2 (<i>RUNX2i>), alkaline phosphatase (<i>ALPi>), osteocalcin (<i>OCNi>), and <i>NPTX1i>, were detected on the basis of quantitative real-time polymerase chain reaction (qPCR) technology. In order to establish a stable <i>NPTX1i>-knockdown hBMSCs cell line, <i>NPTX1i> shRNA lentivirus was constructed and used to infect hBMSCs. ALP staining, alizarin red (AR) staining, and qPCR were employed to assess the impact of <i>NPTX1i>-knockdown on the osteogenic differentiation ability of hBMSCs.
RESULTS:
The results showed that during the osteogenic differentiation of hBMSCs <i>in vitroi>, the mRNA expression levels of osteogenic genes <i>RUNX2i>, <i>ALPi> and <i>OCNi> significantly increased compared with 0 d, while <i>NPTX1i> expression decreased markedly (<i>Pi> < 0.01) as the osteogenic induction period exten-ded. At 72 h post-infection with lentivirus, the result of qPCR indicated that the knockdown efficiency of <i>NPTX1i> was over 60%. After knocking down <i>NPTX1i> in hBMSCs, RNA was extracted from both the <i>NPTX1i>-knockdown group (sh <i>NPTX1i> group) and the control group (shNC group) cultured in regular proliferation medium. The results of qPCR showed that the expression levels of osteogenic-related genes <i>RUNX2i> and osterix (<i>OSXi>) were significantly higher in the sh <i>NPTX1i> group compared with the shNC group (<i>Pi> < 0.01). ALP staining revealed a significantly deeper coloration in the sh <i>NPTX1i> group than in the shNC group at the end of 7 d of osteogenic induction. AR staining demonstrated a marked increase in mineralized nodules in the sh <i>NPTX1i> group compared with the shNC group at the end of 14 d of osteogenic induction.
CONCLUSION
<i>NPTX1i> exerts a modulatory role in the osteogenic differentiation of hBMSCs, and its knockdown has been found to enhance the osteogenic differentiation of hBMSCs. This finding implies that <i>NPTX1i> could potentially serve as a therapeutic target for the treatment of osteogenic abnormalities, including osteoporosis.
Humans
;
Mesenchymal Stem Cells/cytology*
;
Osteogenesis/genetics*
;
Cell Differentiation/genetics*
;
Nerve Tissue Proteins/genetics*
;
Cells, Cultured
;
C-Reactive Protein/genetics*
;
RNA, Small Interfering/genetics*
;
Core Binding Factor Alpha 1 Subunit/metabolism*
;
Bone Marrow Cells/cytology*
;
Gene Knockdown Techniques
;
Osteocalcin/metabolism*
;
Alkaline Phosphatase/metabolism*
;
RNA, Messenger/metabolism*
9.Effects of LncRNA SNHG20 on epithelial mesenchymal transition and microtubule formation in human oral squamous cell carcinoma cells through targeted regulation of the miR-520c-3p/<i>RAB22Ai> pathway.
Minying MA ; Xiaoqin CHAO ; Yang ZHAO ; Guoting ZHAO
Journal of Peking University(Health Sciences) 2025;57(1):26-32
OBJECTIVE:
To investigate the effects of LncRNA SNHG20 on epithelial mesenchymal transition (EMT) and microtubule formation in human oral squamous cell carcinoma (OSCC) cells through targeted regulation of the miR-520c-3p/<i>RAB22Ai> pathway.
METHODS:
After real-time fluorescence quantitative detection of LncRNA SNHG20, miR-520c-3p, <i>RAB22Ai> mRNA expression levels in OSCC tissues and cells, dual luciferase reporter assay was used to detect the relationship between the three. OSCC cells were randomly separated into control group, sh-NC group, sh-SNHG20 group, sh-SNHG20+anti NC group, and sh-SNHG20+anti miR-520c-3p group. Western blotting was used to detect the expression of N-cadherin, vimentin, and E-cadherin proteins in the OSCC cells. The morphology of HSC-3 cells was observed under microscope. Changes in the number of microtubules formed were detected. The effect of LncRNA SNHG20 on the growth of OSCC tumors and the expression levels of LncRNA SNHG20, miR-520c-3p and RAB22 A in the transplanted tumors were detected by nude mice tumorigenesis experiment.
RESULTS:
LncRNA SNHG20 and <i>RAB22Ai> mRNA were upregulated in the OSCC tissues and cells, while miR-520c-3p was downregulated (<i>Pi> < 0.05). There were binding sites between LncRNA SNHG20 and miR-520c-3p, RAB22A and miR-520c-3p, which had targeted regulation relationship. Compared with the sh-NC group, the sh-SNHG20 group had fewer stromal like cells, more epithelial like cells, incomplete microtubule structure, and fewer nodules. LncRNA SNHG20, RAB22A, N-Cadherin, and vimentin were downregulated, while miR-520c-3p and E-cadherin were upregulated (<i>Pi> < 0.05). Compared with the sh-SNHG20+anti-NC group, the sh-SNHG20+anti-miR-520c-3p group had a higher number of stromal like cells, a lower number of epithelioid cells, tighter microtubule arrangement, and more microtubule nodules. miR-520c-3p and E-cadherin were downregulated, while RAB22A, N-cadherin, and vimentin were upregulated (<i>Pi> < 0.05). The transplanted tumor of OSCC in sh-SNHG20 group was smaller and lower than that in sh-NC group. The expression levels of LncRNA SNHG20 and RAB22A in the transplanted tumor tissues were lower than those in sh-NC group, and the expression level of miR-520c-3p was higher than that in sh-NC group (<i>Pi> < 0.05).
CONCLUSION
LncRNA SNHG20 promotes epithelial-mesenchymal transition and microtubule formation in human oral squamous cell carcinoma cells by targeting the miR-520c-3p/<i>RAB22Ai> pathway. Inhibiting the expression of LncRNA SNHG20 can target and regulate the miR-520c-3p/<i>RAB22Ai> pathway to inhibit EMT and microtubule formation in OSCC cells.
Humans
;
RNA, Long Noncoding/genetics*
;
MicroRNAs/metabolism*
;
rab GTP-Binding Proteins/metabolism*
;
Epithelial-Mesenchymal Transition/genetics*
;
Cell Line, Tumor
;
Carcinoma, Squamous Cell/metabolism*
;
Animals
;
Microtubules/metabolism*
;
Mouth Neoplasms/genetics*
;
Mice, Nude
;
Mice
;
Gene Expression Regulation, Neoplastic
;
Mice, Inbred BALB C
10.O-GlcNAcylated YTHDF2 promotes bladder cancer progression by regulating the tumor suppressor gene <i>PER1i> via m6A modification.
Li WANG ; Da REN ; Zeqiang CAI ; Wentao HU ; Yuting CHEN ; Xuan ZHU
Journal of Central South University(Medical Sciences) 2025;50(5):827-839
OBJECTIVES:
Bladder cancer is a common malignancy with high incidence and poor prognosis. N6-methyladenosine (m6A) modification is widely involved in diverse physiological processes, among which the m6A recognition protein YTH N6-methyladenosine RNA binding protein F2 (YTHDF2) plays a crucial role in bladder cancer progression. This study aims to elucidate the molecular mechanism by which O-linked <i>Ni>-acetylglucosamine (O-GlcNAc) modification of YTHDF2 regulates its downstream target, period circadian regulator 1 (<i>PER1i>), thereby promoting bladder cancer cell proliferation.
METHODS:
Expression of YTHDF2 in bladder cancer was predicted using The Cancer Genome Atlas (TCGA). Twenty paired bladder cancer and adjacent normal tissues were collected at the clinical level. Normal bladder epithelial cells (SV-HUC-1) and bladder cancer cell lines (T24, 5637, EJ-1, SW780, BIU-87) were examined by quantitative real-time PCR (RT-qPCR), Western blotting, and immunohistochemistry for expression of YTHDF2, PER1, and proliferation-related proteins [proliferating cell nuclear antigen (PCNA), minichromosome maintenance complex component 2 (MCM2), Cyclin D1]. <i>YTHDF2i> was silenced in 5637 and SW780 cells, and cell proliferation was assessed by Cell Counting Kit-8 (CCK-8), colony formation, and EdU assays. Bioinformatics was used to predict glycosylation sites of YTHDF2, and immunoprecipitation (IP) was performed to detect O-GlcNAc modification levels of YTHDF2 in tissues and cells. Bladder cancer cells were treated with DMSO, OSMI-1 (O-GlcNAc inhibitor), or Thiamet G (O-GlcNAc activator), followed by cycloheximide (CHX), to assess YTHDF2 ubiquitination by IP. <i>YTHDF2i> knockdown and Thiamet G treatment were further used to evaluate <i>PER1i> mRNA stability, <i>PER1i> m6A modification, and cell proliferation. TCGA was used to predict PER1 expression in tissues; SRAMP predicted potential PER1 m6A sites. Methylated RNA immunoprecipitation (MeRIP) assays measured PER1 m6A modification. Finally, the effects of knocking down <i>YTHDF2i> and <i>PER1i> on 5637 and SW780 cell proliferation were assessed.
RESULTS:
<i>YTHDF2i> expression was significantly upregulated in bladder cancer tissues compared with adjacent tissues (mRNA: 2.5-fold; protein: 2-fold), which O-GlcNAc modification levels increased 3.5-fold (<i>Pi><0.001). YTHDF2 was upregulated in bladder cancer cell lines, and its knockdown suppressed cell viability (<i>Pi><0.001), downregulated PCNA, MCM2, and CyclinD1 (all <i>Pi><0.05), reduced colony numbers 3-fold (<i>Pi><0.01), and inhibited proliferation. YTHDF2 exhibited elevated O-GlcNAc modification in cancer cells. OSMI-1 reduced YTHDF2 protein stability (<i>Pi><0.01) and enhanced ubiquitination, while Thiamet G exerted opposite effects (<i>Pi><0.001). Thiamet G reversed the proliferation-suppressive effects of <i>YTHDF2i> knockdown, promoting cell proliferation (<i>Pi><0.01) and upregulating PCNA, MCM2, and CyclinD1 (all <i>Pi><0.05). Mechanistically, YTHDF2 targeted PER1 via m6A recognition, promoting <i>PER1i> mRNA degradation. Rescue experiments showed that <i>PER1i> knockdown reversed the inhibitory effect of <i>YTHDF2i> knockdown on cell proliferation, upregulated PCNA, MCM2, and Cyclin D1 (all <i>Pi><0.05), and promoted bladder cancer cell proliferation (<i>Pi><0.001).
CONCLUSIONS
O-GlcNAc modification YTHDF2 promotes bladder cancer development by downregulating the tumor suppressor gene <i>PER1i> through m6A-mediated post-transcriptional regulation.
Humans
;
Urinary Bladder Neoplasms/metabolism*
;
RNA-Binding Proteins/genetics*
;
Cell Proliferation
;
Cell Line, Tumor
;
Disease Progression
;
Acetylglucosamine/metabolism*
;
Adenosine/metabolism*
;
Gene Expression Regulation, Neoplastic
;
Genes, Tumor Suppressor

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