RESUMO
Breast cancer remains one of the leading causes of cancer-associated death in women. MiR-27a is highly expressed in breast cancer tissue. However, the underlying mechanisms that promote breast cancer progression are unknown. In this study, we investigated the regulatory mechanisms of miR-27a and its target glycogen Synthase Kinase 3-ß (GSK-3ß) in breast cancer cells. We found that miR-27a was highly expressed in breast cancer tissues, which downregulated GSK-3ß expression. We further identified GSK-3ß as a direct target of miR-27a, and found that the miR-27a mediated suppression of GSK-3ß activated Wnt/ß-catenin-associated proliferative and invasive factor in breast cancer. The cell transfection assay demonstrated the overexpression of miR-27a also enhanced cell proliferation and invasion, and reduced cell apoptosis through GSK-3ß. Finally, we demonstrated that the overexpression of miR-27a facilitated breast cancer progression through its ability to down-regulate the phosphorylation of GSK-3ß both in vivo and vitro. These findings highlighted miR-27a as a novel therapeutic target in breast cancer.
Assuntos
Neoplasias da Mama/genética , Carcinogênese/genética , Glicogênio Sintase Quinase 3 beta/genética , MicroRNAs/genética , Animais , Apoptose/genética , Mama/patologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Xenoenxertos , Humanos , Células MCF-7 , Camundongos , Fosforilação/genética , Via de Sinalização Wnt/genética , beta Catenina/genéticaRESUMO
Nocardia is a pathogen responsible for a variety of clinical infections. Here, we aimed to investigate the species distribution, clinical manifestations, and antimicrobial susceptibility of Nocardia species over 3 years in two tertiary general hospitals in China. In this retrospective study, a total of 27 Nocardia species were isolated from 27 individuals between January 2017 and December 2019. Nocardia isolates were identified to species level by mass spectrometry and 16S rRNA PCR sequencing. Clinical data were collected from medical records. Antimicrobial susceptibility was determined by the standard Broth microdilution method. The 27 patients with Nocardia infection included 12 males and 15 females with a mean age of 60.11 years. Among 27 Nocardia isolates, 7 species were identified, with the most common species being Nocardia otitidiscaviarum (40.7%). The antimicrobial susceptibility profiles varied between different Nocardia species. Notably, all Nocardia isolates were linezolid susceptible. The majority of Nocardia isolates were collected from a department of respiratory medicine (55.56%) and sputum specimen (44.44%). Pulmonary region was the most involved body site (70.37%) followed by skin (7.4%) and pleural cavity (7.4%). Most patients with Nocardia infection needed combination antibiotic therapy. Two deaths were reported during the treatment period and 24 patients achieved improvement after antibiotic therapy. The clinical manifestations of Nocardia infection and antimicrobial susceptibility profiles varied with diverse Nocardia species. Thus, the accurate identification of these species is crucial for the diagnosis and the selection of antibiotic treatment.
Assuntos
Anti-Infecciosos/farmacologia , Nocardiose/diagnóstico , Nocardiose/tratamento farmacológico , Nocardiose/microbiologia , Nocardia/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , China , Feminino , Humanos , Linezolida/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , RNA Ribossômico 16S/metabolismo , Estudos Retrospectivos , Análise de Sequência de RNA , Especificidade da EspécieRESUMO
Semaphorin 4D (Sema4D) is a transmembrane protein that supports contact-dependent amplification of platelet activation by collagen before being gradually cleaved by the metalloprotease ADAM17, as we have previously shown. Cleavage releases a soluble 120-kDa exodomain fragment for which receptors exist on platelets and endothelial cells. Here we have examined the mechanism that regulates Sema4D exodomain cleavage. The results show that the membrane-proximal cytoplasmic domain of Sema4D contains a binding site for calmodulin within the polybasic region Arg762-Lys779. Coprecipitation studies show that Sema4D and calmodulin are associated in resting platelets, forming a complex that dissociates upon platelet activation by the agonists that trigger Sema4D cleavage. Inhibiting calmodulin with W7 or introducing a membrane-permeable peptide corresponding to the calmodulin-binding site is sufficient to trigger the dissociation of Sema4D from calmodulin and initiate cleavage. Conversely, deletion of the calmodulin-binding site causes constitutive shedding of Sema4D. These results show that (1) Sema4D is a calmodulin-binding protein with a site of interaction in its membrane-proximal cytoplasmic domain, (2) platelet agonists cause dissociation of the calmodulin-Sema4D complex, and (3) dissociation of the complex is sufficient to trigger ADAM17-dependent cleavage of Sema4D, releasing a bioactive fragment.
