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 N-acetylglucosamine (O-GlcNAc) modification of YTHDF2 regulates its downstream target, period circadian regulator 1 (PER1), 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]. YTHDF2 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. YTHDF2 knockdown and Thiamet G treatment were further used to evaluate PER1 mRNA stability, PER1 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 YTHDF2 and PER1 on 5637 and SW780 cell proliferation were assessed. RESULTS: YTHDF2 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 (P<0.001). YTHDF2 was upregulated in bladder cancer cell lines, and its knockdown suppressed cell viability (P<0.001), downregulated PCNA, MCM2, and CyclinD1 (all P<0.05), reduced colony numbers 3-fold (P<0.01), and inhibited proliferation. YTHDF2 exhibited elevated O-GlcNAc modification in cancer cells. OSMI-1 reduced YTHDF2 protein stability (P<0.01) and enhanced ubiquitination, while Thiamet G exerted opposite effects (P<0.001). Thiamet G reversed the proliferation-suppressive effects of YTHDF2 knockdown, promoting cell proliferation (P<0.01) and upregulating PCNA, MCM2, and CyclinD1 (all P<0.05). Mechanistically, YTHDF2 targeted PER1 via m⁶A recognition, promoting PER1 mRNA degradation. Rescue experiments showed that PER1 knockdown reversed the inhibitory effect of YTHDF2 knockdown on cell proliferation, upregulated PCNA, MCM2, and Cyclin D1 (all P<0.05), and promoted bladder cancer cell proliferation (P<0.001). CONCLUSIONS O-GlcNAc modification YTHDF2 promotes bladder cancer development by downregulating the tumor suppressor gene PER1 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

Gliomas are the most common central nervous system tumours; they are highly aggressive and have a poor prognosis. RGS16 belongs to the regulator of G-protein signalling (RGS) protein family, which plays an important role in promoting various cancers, such as breast cancer, pancreatic cancer, and colorectal cancer. Moreover, previous studies confirmed that let-7c-5p, a well-known microRNA, can act as a tumour suppressor to regulate the progression of various tumours by inhibiting the expression of its target genes. However, whether RGS16 can promote the progression of glioma and whether it is regulated by miR let-7c-5p are still unknown. Here, we confirmed that RGS16 is upregulated in glioma tissues and that high expression of RGS16 is associated with poor survival. Ectopic deletion of RGS16 significantly suppressed glioma cell proliferation and migration both in vitro and in vivo. Moreover, RGS16 was validated as a direct target gene of miR let-7c-5p. The overexpression of miR let-7c-5p obviously downregulated the expression of RGS16, and knocking down miR let-7c-5p had the opposite effect. Thus, we suggest that the suppression of RGS16 by miR let-7c-5p can promote glioma progression and may serve as a potential prognostic biomarker and therapeutic target in glioma.
Humans ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; MicroRNAs/metabolism* ; Glioma/genetics* ; Genes, Tumor Suppressor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Cell Line, Tumor

Genes, p53 ; Genetic Predisposition to Disease ; Germ-Line Mutation ; Humans ; Li-Fraumeni Syndrome/genetics* ; Tumor Suppressor Protein p53/genetics*

BACKGROUND: The pathogenesis of osteosarcoma (OS) is still unclear, and it is still necessary to find new targets and drugs for anti-OS. This study aimed to investigate the role and mechanism of the anti-OS effects of miR-296-5p. METHODS: We measured the expression of miR-296-5p in human OS cell lines and tissues. The effect of miR-296-5p and its target gene staphylococcal nuclease and tudor domain containing 1 on proliferation, migration, and invasion of human OS lines was examined. The Student's t test was used for statistical analysis. RESULTS: We found that microRNA (miR)-296-5p was significantly downregulated in OS cell lines and tissues (control vs. OS, 1.802 ± 0.313 vs. 0.618 ± 0.235, t = 6.402, P < 0.01). Overexpression of miR-296-5p suppressed proliferation, migration, and invasion of OA cells. SND1 was identified as a target of miR-296-5p by bioinformatic analysis and dual-luciferase reporter assay. Overexpression of SND1 abrogated the effects induced by miR-296-5p upregulation (miRNA-296-5p vs. miRNA-296-5p + SND1, 0.294 ± 0.159 vs. 2.300 ± 0.277, t = 12.68, P = 0.003). CONCLUSION Our study indicates that miR-296-5p may function as a tumor suppressor by targeting SND1 in OS.
Bone Neoplasms/genetics* ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Endonucleases/genetics* ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; MicroRNAs/genetics* ; Osteosarcoma/genetics*

PTEN hamartoma tumor syndrome is a spectrum of disorders characterized by unique phenotypic features including multiple hamartomas caused by mutations of the tumor suppressor gene PTEN. Cowden syndrome and Bannayan–Riley–Ruvalcaba syndrome are representative diseases, and both have several common clinical features and differences. Because PTEN mutations are associated with an increased risk of malignancy including breast, thyroid, endometrial, and renal cancers, cancer surveillance is an important element of disease management. We report a germline mutation of the PTEN (c.723dupT, exon 7) identified in a young woman with a simultaneous occurrence of breast cancer, dermatofibrosarcoma protuberans, and follicular neoplasm. This case suggests that it is critical for clinicians to recognize the phenotypic features associated with these syndromes to accurately diagnose them and provide preventive care.
Breast ; Breast Neoplasms ; Dermatofibrosarcoma ; Disease Management ; Exons ; Female ; Genes, Tumor Suppressor ; Germ-Line Mutation ; Hamartoma ; Hamartoma Syndrome, Multiple ; Humans ; Kidney Neoplasms ; Thyroid Gland

A variety of clonal cytogenetic abnormalities have been reported in aggressive natural killer (NK)-cell lymphoma and leukemia. Recent chromosomal microarray studies have shown both gain and loss of 1q and loss of 7p as recurrent abnormalities in aggressive NK-cell leukemia. Here, we report a case of aggressive NK-cell leukemia with complex chromosomal gains and losses, as confirmed by chromosomal microarray analysis. The patient showed an aggressive clinical course, which was complicated by hemophagocytic lymphohistiocytosis. Conventional cytogenetic analysis revealed trisomy 3 and 1q gain only. However, chromosomal microarray analysis detected an additional gain of 1q21.1–q24.2 and a loss of 1q24.2–q31.3. These abnormal lesions might play a role in the pathogenesis of aggressive NK-cell leukemia by inactivating tumor suppressor genes or by activating oncogenes. These results suggest that chromosomal microarray analysis may be used to provide further genetic information for patients with hematological malignancies, including aggressive NK-cell leukemia.
Chromosome Aberrations ; Cytogenetic Analysis ; Genes, Tumor Suppressor ; Hematologic Neoplasms ; Humans ; Leukemia ; Lymphohistiocytosis, Hemophagocytic ; Lymphoma ; Microarray Analysis ; Oncogenes ; Trisomy

BACKGROUND: We previously reported the frequent neurofibromatosis 2 (NF2) gene mutations in anaplastic thyroid cancers in association with the BRAF V600E mutation. We aimed to investigate the role of NF2 in thyroid cancer with BRAF mutation. METHODS: To identify the function of NF2 in thyroid cancers, we investigated the changes in cell proliferation, colon formation, migration and invasion of thyroid cancer cells (8505C, BHT101, and KTC-1) with BRAF V600E mutation after overexpression and knock-down of NF2. We also examined how cell proliferation changed when NF2 was mutagenized. Human NF2 expression in papillary thyroid carcinoma (PTC) was analyzed using the The Cancer Genome Atlas (TCGA) data. RESULTS: First, NF2 was overexpressed in 8505C and KTC-1 cells. Compared to control, NF2 overexpressed group of both thyroid cancer cells showed significant inhibition in cell proliferation and colony formation. These results were also confirmed by cell migration and invasion assay. After knock-down of NF2 in 8505C cells, there were no significant changes in cell proliferation and colony formation, compared with the control group. However, after mutagenized S288* and Q470* sites of NF2 gene, the cell proliferation increased compared to NF2 overexpression group. In the analysis of TCGA data, the mRNA expression of NF2 was significantly decreased in PTCs with lateral cervical lymph node (LN) metastasis compared with PTCs without LN metastasis. CONCLUSION: Our study suggests that NF2 might play a role as a tumor suppressor in thyroid cancer with BRAF mutation. More studies are needed to elucidate the mechanism how NF2 acts in thyroid cancer with BRAF mutation.
Cell Movement ; Cell Proliferation ; Colon ; Genes, Neurofibromatosis 2 ; Genes, Tumor Suppressor ; Genome ; Humans ; Lymph Nodes ; Neoplasm Metastasis ; Neurofibromatosis 2 ; RNA, Messenger ; Thyroid Carcinoma, Anaplastic ; Thyroid Gland ; Thyroid Neoplasms

OBJECTIVE: To explore the role of miR-593 in regulating the proliferation of colon cancer cells and the molecular mechanism. METHODS: Bioinformatics analysis identified PLK1 as the possible target gene of miR-593. Luciferase assay was employed to verify the binding between miR-593 and PLK1, and qRT-PCR and Western blotting were used to verify that PLK1 was the direct target gene of miR-593. CCK-8 assay was performed to test the hypothesis that miR-593 inhibited the proliferation of colon cancer cells by targeting PLK1. RESULTS: Luciferase assay identified the specific site of miR-593 binding with PLK1. Western blotting showed a significantly decreased expression of PLK1 in the colon cancer cells transfected with miR-593 mimics and an increased PLK1 expression in the cells transfected with the miR-593 inhibitor as compared with the control cells ( < 0.05). The results of qRT-PCR showed no significant differences in the expression levels of PLK1 among the cells with different treatments ( > 0.05). The cell proliferation assay showed opposite effects of miR-593 and PLK1 on the proliferation of colon cancer cells, and the effect of co-transfection with miR-593 mimic and a PLK1-overexpressing plasmid on the cell proliferation was between those in PLK1 over-expressing group and miR-593 mimic group. CONCLUSIONS miR-593 inhibits the proliferation of colon cancer cells by down-regulating PLK1 and plays the role as a tumor suppressor in colon cancer.
Binding Sites ; Cell Cycle Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms ; metabolism ; pathology ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; In Vitro Techniques ; MicroRNAs ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sincalide ; metabolism ; Transfection

OBJECTIVE: To investigate the effect of the long chain non-coding RNA H19 (lncRNA H19) on the invasion and migration of oral cancer cells and its related molecular mechanism. METHODS: The expression levels of lncRNA H19, miR-107, and cyclin-dependent kinase 6 (CDK6) in the immortalized oral epithelial cell line HIOEC and the oral cancer cell line CAL27 were detected by real-time quantitative polymerase chain reaction. CAL27 cells were transfected with siRNA H19, miR-107 mimics, pcDNA H19, or anti-miR-107, and the effects of H19 and miR-107 on the invasion and migration of cells were examined via Transwell assay. The TargetScan database predicted the targeting of H19, miR-107, and CDK6. Double luciferase reporter gene assay was performed to detect interactions among H19, miR-107, and CDK6. Western blot analysis was conducted to examine the effects of H19 and miR-107 on the protein level of the target gene CDK6. RESULTS: Compared with that in HIOEC cells, the expression of H19 was significantly increased in CAL27 cells (P<0.05). After transfection with siRNA H19, the expression of H19 decreased, and the invasion and migration ability of CAL27 cells were inhibited (P<0.05). H19 could bind specifically to the 3'-UTR of miR-107 to modulate the expression of miR-107. Compared with that in HIOEC cells, the expression of miR-107 significantly decreased in CAL27 cells (P<0.05). The expression of miR-107 increased after transfection with siRNA H19, and anti-mir-107 co-transfection could promote the invasion and migration ability of siRNA H19 in CAL27 cells (P<0.05). Compared with that in HIOEC cells, CDK6 expression significantly increased in CAL27 cells (P<0.05), and the expression level of the gene was coregulated by H19 and miR-107 (P<0.05). CONCLUSIONS lncRNA H19 plays an important role in the development of oral cancer. It can regulate the invasion and migration of oral cancer cells by targeting the miR-107/CDK6 signaling axis.
Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; MicroRNAs ; Mouth Neoplasms ; RNA, Long Noncoding

BACKGROUND/AIMS: Phosphatase and tensin homolog (PTEN) is a known tumor suppressor gene that is downregulated in hepatocellular carcinoma (HCC). Here, we investigated the association between single nucleotide polymorphisms (SNPs) of PTEN and HCC development in patients with hepatitis B virus (HBV) infection. METHODS: Six SNPs of PTEN at positions rs1234221, rs1903860, rs1234220, rs1903858, rs2299941, and rs17431184 were analyzed in a development population (417 chronic HBV carriers without HCC and 281 chronic HBV carriers with HCC). PTEN rs1903858, rs1903860, and rs2299941 SNPs were further assessed for the development of HCC in a validation population of 200 patients with HBV-related liver cirrhosis. RESULTS: In the development population, PTEN rs1903860 C allele, rs1903858 G allele, and rs2299941 G allele were associated with a low risk of HCC. The haplotype A-T-A-A-A was associated with an increased risk of HCC (recessive model; odds ratio=2.277, 95% confidence interval [CI] =1.144-4.532, P=0.019). In the validation population, PTEN rs2299941 G allele was the only significant protective genetic polymorphism related to HCC development after adjustment for age and sex (hazard ratio=0.582, 95% CI =0.353–0.962, P=0.035). CONCLUSIONS: These findings suggest that genetic polymorphisms in PTEN may affect HCC development in patients with chronic HBV infection.
Alleles ; Carcinoma, Hepatocellular ; Genes, Tumor Suppressor ; Haplotypes ; Hepatitis B virus ; Hepatitis B ; Hepatitis ; Humans ; Liver Cirrhosis ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide