RESUMO
Increasing evidence suggests that epigenetic mechanisms play a role in the etiology of autism spectrum disorder (ASD). To date, several studies have attempted to identify epigenetic biomarkers for ASD. However, reliable markers remain to be established and most of these studies have focused on pediatric patients with ASD. In this study, we sought to find an epigenetic DNA methylation biomarker from peripheral blood for adult patients with high-functioning ASD. DNA methylation profiles were analyzed using the Illumina 450 K methylation array. To identify robust candidate markers, we employed two types of machine-learning algorithms for marker selection. We identified a potential marker (cg20793532) for which is the AUC value was 0.79. Notably, cg20793532 was annotated to the PPP2R2C gene, which was hypermethylated and down-regulated in blood from ASD patients compared to that in the controls. Although requiring careful interpretation, this pilot study seems to provide a potential blood biomarker for identifying individuals with high-functioning ASD.
Assuntos
Transtorno do Espectro Autista/genética , Metilação de DNA , Regulação para Baixo , Proteína Fosfatase 2/genética , Análise de Sequência de DNA/métodos , Adolescente , Adulto , Transtorno do Espectro Autista/sangue , Estudos de Casos e Controles , Criança , Pré-Escolar , Epigênese Genética , Feminino , Estudos de Associação Genética , Marcadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Projetos Piloto , Proteína Fosfatase 2/sangueRESUMO
Protein phosphatase 2A (PP2A) was reported to play an important role in cancer development; however, the relationship between PP2A and cervical cancer development has yet to be fully understood. The present study aimed to explore the role of PP2A in the development of cervical cancer. Serum levels of PP2A were detected by ELISA in 23 patients with cervical cancer and 30 patients with benign cervical lesions. Furthermore, the PP2A activities and the mRNA and protein levels of PP2A were measured in cervical cancer (n=8) and chronic cervicitis (n=10) tissues. The results showed that the serum levels of PP2A were significantly reduced in patients with cervical cancer. Further studies showed that not only the activities of PP2A but also the mRNA and protein levels of PP2A were significantly decreased in cervical cancer tissues. Wound healing and Transwell assays demonstrated that pharmacological and genetic upregulation of PP2A could inhibit the migration of HeLa cells, but the downregulation of PP2A promoted cellular migration. The activation of PP2A also inhibited the remodeling of actin and the activity of mitogen-activated protein kinases (MAPKs) including p-JNK, p-p38 and p-ERK. Meanwhile, the activation of PP2A was found to downregulate MMP-9 levels, which further inhibited the migration and invasion of HeLa cells. In conclusion, our data suggest that the activity and expression of PP2A are significantly reduced in cervical cancer tissues, and the activation of PP2A may inhibit the migration of cervical cancer cells by inhibiting the phosphorylation of p-JNK, p-p38 and the p-ERK/MAPK signaling pathway as well as by downregulating MMP-9, implying that PP2A plays an important role in cervical cancer development.
Assuntos
Movimento Celular , MAP Quinase Quinase 4/metabolismo , Sistema de Sinalização das MAP Quinases , Proteína Fosfatase 2/metabolismo , Neoplasias do Colo do Útero/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Adulto , Idoso , Carcinoma , Estudos de Casos e Controles , Feminino , Células HeLa , Humanos , Pessoa de Meia-Idade , Proteína Fosfatase 2/sangue , Neoplasias do Colo do Útero/sangue , Neoplasias do Colo do Útero/patologiaRESUMO
Protein phosphatase 2A (PP2A) is a heterotrimeric protein phosphatase consisting of a 36-kD catalytic C subunit (PP2Ac). This study aimed to explore the prognostic and biological significance of PP2Ac in human hepatocellular carcinoma (HCC). High PP2Ac expression was significantly (P < 0.01) associated with serum hepatitis B surface antigen positivity, serum hepatitis B e antigen positivity, liver cirrhosis, moderate to poor differentiation grade, advanced disease stage, intrahepatic metastasis, and early recurrence in HCC. Multivariate analysis revealed PP2Ac as an independent prognostic factor for overall survival. Enforced expression of hepatitis B virus X protein (HBx) and its carboxyl-terminal truncated isoform induced PP2Ac expression in HCC cells. Co-immunoprecipitation assay revealed a direct interaction between PP2Ac and HBx. Small interfering RNA-mediated knockdown of PP2Ac significantly inhibited in vitro cell proliferation, colony formation, migration, and invasion and reduced tumor growth in an xenograft mouse model. In contrast, overexpression of PP2Ac promoted HCC cell proliferation, colony formation, and tumorigenesis. Additionally, silencing of PP2Ac impaired the growth-promoting effects on HepG2 HCC cells elicited by overexpression of carboxyl-terminal truncated HBx. Gene expression profiling analysis showed that PP2Ac downregulation modulated the expression of numerous genes involved in cell cycle and apoptosis regulation. Collectively, PP2Ac upregulation has a poor prognostic impact on the overall survival of HCC patients and contributes to the aggressiveness of HCC. PP2Ac may represent a potential therapeutic target for HCC.
Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Proteína Fosfatase 2/genética , Transativadores/biossíntese , Idoso , Animais , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/virologia , Ciclo Celular/genética , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Antígenos de Superfície da Hepatite B/sangue , Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , Vírus da Hepatite B/patogenicidade , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Masculino , Camundongos , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Prognóstico , Proteína Fosfatase 2/antagonistas & inibidores , Proteína Fosfatase 2/biossíntese , Proteína Fosfatase 2/sangue , Transativadores/sangue , Proteínas Virais Reguladoras e AcessóriasRESUMO
Platelet activation is accompanied with the phosphorylation of a number of proteins on serine (Ser) and threonine (Thr) residues. The phosphorylation level of these proteins is dependent upon the protein kinase/phosphatase activity ratio. The aim of this study was to investigate the consequences of inhibiting protein phosphatase 1 (PP1) and 2A (PP2A) on platelet functions. Protein phosphatases were inhibited by preincubation of platelet rich plasma (PRP) samples with calyculin-A (CLA). Subsequently, platelets were activated by thrombin-receptor activating peptide (TRAP) and platelet aggregation, platelet-derived microparticle (PMP) formation, surface expressions of P-selectin (CD62), lysosome-associated membrane protein (CD63), glycoprotein Ib and IIb were examined. Phosphatase activity was determined by using phosphorylated 20 kDa myosin light chain (P-MLC20) as substrate. In CLA-treated platelets substantial decrease of P-MLC20 phosphatase activity was observed. CLA significantly suppressed TRAP-induced surface expression of P-selectin and CD63 in a concentration-dependent manner as compared to non-treated samples and moderately decreased platelet aggregation. In TRAP-activated samples, 50 nM of CLA pretreatment completely abolished the level of PMPs and the prevention of GPIb downregulation was also observed; however, no difference was found in GPIIb expression. In conclusion, PP1 and PP2A-catalyzed dephosphorylation processes have crucial roles in PMP formation and in the regulation of alpha-granule and lysosome secretion in human platelets.