ABSTRACT
BACKGROUND: SND1 participates in tumorigenesis, tumour invasion and metastasis in different cancers. Previous studies have shown that SND1 can promote the invasion and migration of breast cancer cells. Triple-negative breast cancer (TNBC) is a specific breast cancer subtype with high metastatic potential and poor prognosis. However, the specific roles and mechanisms of SND1 in TNBC metastasis remain unaddressed. METHODS: Immunostaining was used to detect the SND1 expression in tissue samples of 58 TNBC and 10 glioblastomas (GBM) as positive control. The correlation between SND1 expression and patient prognosis was assessed using the Kaplan-Meier estimator. The gene expression was evaluated by qRT-PCR, Western blot and immunofluorescence analyses. Gene Ontology analysis, ChIP, a dual-luciferase reporter assay, EMSA, and 3C analysis were applied to identify SND1-activated target genes. Bisulfite sequencing PCR and MeDIP were used to detect DNA methylation. We also used wound healing, Transwell and orthotopic implantation assays to investigate the function of SND1 in TNBC cell migration and invasion. RESULTS: The data of immunohistochemistry manifested that SND1 is the overexpression in metastasized TNBC and an independent factor for TNBC prognosis. SND1 knockdown inhibited the migration and invasion of TNBC cells. We found that SND1 promotes the metastatic phenotype of TNBC cells by epigenetically altering chromatin conformational interactions, which in turn activates DNMT3A transcription. Then, DNMT3A attenuates CCND1 expression by inducing CCND1 gene methylation, leading to TNBC metastasis. CONCLUSION: SND1 can promote the invasion and migration of TNBC cells by promoting DNMT3A expression and suppressing CDH1 activity. SND1 is a potential biomarker and a promising therapeutic target for TNBC.
Subject(s)
Triple Negative Breast Neoplasms , Humans , Triple Negative Breast Neoplasms/pathology , Cell Line, Tumor , Chromatin , Cell Proliferation/genetics , DNA Methylation , Cell Movement/genetics , Gene Expression Regulation, Neoplastic , Endonucleases/genetics , Endonucleases/metabolism , Antigens, CD/metabolism , Cadherins/geneticsABSTRACT
BACKGROUND: Upregulation of staphylococcal nuclease domain-containing protein 1 (SND1) is a common phenomenon in different human malignant tissues. However, little information is available on the underlying mechanisms through which SND1 affects glioma cell proliferation and invasion. METHODS: SND1, Ras homolog family member A (RhoA), and marker of proliferation Ki-67 (MKI67) were analyzed in 187 gliomas by immunostaining. The correlation between those markers and patients' prognoses was assessed using the Kaplan-Meier estimator. Gene Ontology, chromatin immunoprecipitation, electrophoretic mobility shift assay, and chromosome conformation capture were applied to identify SND1-activated target genes. We also used MTT, colony formation, transwell and orthotopic implantation assays to investigate SND1 function in glioma cell proliferative and invasive activity. RESULTS: We identified SND1 and RhoA as independent predictors of poor prognosis in glioma patients. SND1 knockdown significantly suppressed the proliferation and invasion of glioma cells. Mechanistically, we discovered that SND1 facilitated malignant glioma phenotypes by epigenetically inducing chromatin topological interaction, which activated downstream RhoA transcription. RhoA sequentially regulated expression of CCND1, CCNE1, CDK4, and CDKN1B and accelerated G1/S phase transition in glioma cell proliferation. CONCLUSIONS: Our findings identify SND1 as a novel chromatin architectural modifier and promising prognostic indicator for glioma classification and treatment.
Subject(s)
Biomarkers, Tumor/metabolism , Brain Neoplasms/pathology , Cell Proliferation , Endonucleases/metabolism , Gene Expression Regulation, Neoplastic , Glioma/pathology , rhoA GTP-Binding Protein/genetics , Animals , Apoptosis , Biomarkers, Tumor/genetics , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Case-Control Studies , Cell Cycle , Endonucleases/genetics , Glioma/genetics , Glioma/metabolism , Humans , Mice , Mice, Inbred NOD , Mice, SCID , Neoplasm Invasiveness , Prognosis , Survival Rate , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
To identify the function and underlying mechanisms of HMGA2 on the prognosis and invasion of gliomas, HMGA2 was detected by immunohistochemistry. The Kaplan-Meier and Cox's regression analysis results showed that higher HMGA2 level predicted the poorer outcomes of glioma patients. ChIP-qPCR, DNA electrophoretic mobility shift assay, chromosome conformation capture, and co-immunoprecipitation were applied to identify HMGA2-activated target sites, which were further verified by mRNA and protein expression detection. Transwell and orthotopic implantation were used to investigate the roles of HMGA2 in glioma cells. HMGA2 shRNA transfection inhibited glioblastoma invasion. Mechanistically, we first discovered that HMGA2, together with GCN5, facilitated the invasion of glioma cells via inducing chromatin conformational remodeling of the MMP2 gene promoter and epigenetically activating MMP2 gene transcription. Our results indicated that HMGA2, as a novel GCN5 recognition partner and histone acetylation modulator, may be novel prognostic indicator and promising glioma treatment target.
