Circular RNA circ-TNRC6B inhibits the proliferation and invasion of esophageal squamous cell carcinoma cells by regulating the miR-452-5p/DAG1 axis.

Previous studies have uncovered the key role of circular RNAs (circRNAs) in various diseases, including cancer. However, the growth-inhibitory effects of circRNAs on esophageal squamous cell carcinoma (ESCC) have not been completely elucidated. This study characterized a newly identified circRNA derived from exons 9-13 of TNRC6B (named circ-TNRC6B). The expression of circ-TNRC6B in ESCC tissues was markedly downregulated when compared to that in non-tumor tissues. In 53 ESCC cases, circ-TNRC6B expression was negatively correlated with the T stage. Multivariate Cox regression analysis showed that circ-TNRC6B upregulation was an independent protective factor for ESCC patients' prognosis. Overexpression and knockdown functional experiments demonstrated that circ-TNRC6B inhibited ESCC cell proliferation, migration, and invasion. RNA immunoprecipitation and dual-luciferase reporter assays demonstrated that circ-TNRC6B sponges oncogenic miR-452-5p to upregulate the expression and activity of DAG1. Treatment with miR-452-5p inhibitor partially reversed the circ-TNRC6B-induced changes in the biological behavior of ESCC cells. These findings demonstrated that circ-TNRC6B exerts a tumor-suppressing effect in ESCC through the miR-452-5p/DAG1 axis. Thus, circ-TNRC6B is a potential prognostic biomarker for the clinical management of ESCC.

Role and mechanism of miR-548-3p/ DAG1 in the occurrence and malignant transformation of laryngeal carcinoma / Papel y mecanismo de miR-548-3p/DAG1 en la aparición y transformación maligna del carcinoma de laringe

Abstract The AMC-HN-8 cell line and the primary human laryngeal epithelial cell lines were utilized in this work to explore the molecular mechanism of miR-548-3p regulating the gene DAG1 to induce the occurrence and malignant transformation of laryngeal carcinoma. Non-coding RNA miR-548- 3p overexpression plasmid, interference plasmid and blank plasmid were constructed, and the plasmids were transfected into AMC-HN-8 cells, respectively. Meanwhile, a non-transfected plasmid group and a human laryngeal epithelial primary cell group were set up. Five groups of cells were named as NC (Normal control), Model, Ov-miR-548-3p, Sh-miR-548-3p and Blank-plasmid group. The luciferase reporter experiment was used to analyze the regulation characteristics of hsa-miR-548-3p on dystrophin-associated glycoprotein 1 (DAG1). Immunofluorescence was used to analyze the relative expression characteristics of the protein DAG1. The cell cloning experiment was used to analyze the proliferation characteristics of AMC-HN-8. The scratch healing test was used to analyze the migration ability of AMC-HN-8. The transwell test was used to analyze the invasion ability of AMC-HN-8. The RT-PCR was used to analyze the expression level of miR-548-3p. Western blot experiments were used to analyze the expression of protein DAG1, laminin α2 (LAMA2) and utrophin (UTRN). The luciferase report experiment and immunofluorescence test found that the expression of DAG1 and miR-548-3p are positively correlated. Cell cloning, scratching and migration experiments identified that the activity of laryngeal cancer cells was positively correlated with the expression of DAG1. The results of Western blot analysis further strengthened the above conclusions. Through carrying out research on the cellular levels, our work has demonstrated that miR-548-3p regulated the content of protein DAG1, and then further induced malignant transformation of laryngeal carcinoma.

Resumen En este trabajo se utilizaron la línea celular AMC-HN-8 y la línea celular epitelial laríngea humana primaria, para explorar el mecanismo molecular regulador del miR-548-3p sobre el gen DAG1 para inducir la aparición y la transformación maligna del carcinoma laríngeo. Se construyeron el plásmido de sobreexpresión de miR-548-3p de ARN no codificante, el plásmido de interferencia y el plásmido en blanco, y los plásmidos se transfectaron en células AMCHN-8 respectivamente. Mientras tanto, se establecieron un grupo de plásmidos no transfectados y un grupo de células primarias epiteliales laríngeas humanas. Se nombraron cinco grupos de células como NC (control normal), modelo, OvmiR-548-3p, Sh-miR-548-3p y grupo de plásmido en blanco. El experimento indicador de luciferasa se utilizó para analizar las características de regulación de hsa-miR-548-3p en la glicoproteína 1 asociada a distrofina (DAG1). Se utilizó inmunofluorescencia para analizar las características de expresión relativa de la proteína DAG1. El experimento de clonación celular se utilizó para analizar las características de proliferación de AMC-HN-8. Se utilizó la prueba de cicatrización por rascado para analizar la capacidad de migración de AMC-HN-8. La prueba de transwell se utilizó para analizar la capacidad de invasión de AMCHN-8. Se utilizó RT-PCR para analizar el nivel de expresión de miR-548-3p. Se usó un experimento de transferencia Western (Western blot) para analizar las expresiones de la proteína DAG1, laminina α2 (LAMA2) y utrofina (UTRN). El experimento de reporte de luciferasa y la prueba de inmunofluorescencia encontraron que la expresión de DAG1 y miR-548-3p están positivamente correlacionadas. Los experimentos de clonación celular, rascado y migración, identificaron que la actividad de las células cancerosas de laringe se correlacionó positivamente con la expresión de DAG1. Los resultados del análisis de transferencia Western fortalecieron aún más las conclusiones anteriores. A través de la investigación a nivel celular, nuestro proyecto ha demostrado que miR-548-3p regula el contenido de la proteína DAG1 y luego induce la transformación maligna del carcinoma de laringe.

Whole exome sequencing identified a novel DAG1 mutation in a patient with rare, mild and late age of onset muscular dystrophy-dystroglycanopathy.

Muscular dystrophy-dystroglycanopathy (limb-girdle), type C, 9 (MDDGC9) is the rarest type of autosomal recessive muscular dystrophies. MDDGC9 is manifested with an early onset in childhood. Patients with MDDGC9 usually identified with defective glycosylation of DAG1, hence it is known as "dystroglycanopathies". Here, we report a Chinese pedigree presented with mild MDDGC9. The proband is a 64 years old Chinese man. In this family, both the proband and proband's younger brother have been suffering from mild and late onset MDDGC9. Muscle biopsy showed that the left deltoid muscle with an advanced stage of dystrophic change. Immunohistochemistry staining of dystrophin, α-sarcoglycan, ß-sarcoglycan and dysferlin are normal. Molecular genetic analysis of the proband has been done with whole exome sequencing. A homozygous novel missense mutation (c.2326C>T; p.R776C) in the exon 3 of the DAG1 gene has been identified in the proband. Sanger sequencing revealed that this missense mutation is co-segregated well among the affected and unaffected (carrier) family members. This mutation is not detected in 200 normal healthy control individuals. This novel homozygous missense mutation (c.2326C>T) causes substitution of arginine by cystine at the position of 776 (p.R776C) which is evolutionarily highly conserved. Immunoblotting studies revealed that a significant reduction of α-dystroglycan expression in the muscle tissue. The novelty of our study is that it is a first report of DAG1 associated muscular dystrophy-dystroglycanopathy (limb-girdle), type C, 9 (MDDGC9) with mild and late age of onset. In Chinese population this is the first report of DAG1 associated MDDGC9.

Walker-Warburg syndrome and tectocerebellar dysraphia: A novel association caused by a homozygous DAG1 mutation.

OBJECTIVES: To elaborate the imaging phenotype associated with a homozygous c.743C > del frameshift mutation in DAG1 leading to complete absence of both α- and ß-dystroglycan previously reported in a consanguineous Israeli-Arab family. METHODS: We analyzed prenatal and postnatal imaging data of patients from a consanguineous Israeli-Arab kindred harboring the DAG1 mutation. RESULTS: The imaging studies (fetal ultrasound, CT scan and postnatal MRI) demonstrated: flat cortex (abnormally thick with irregular pebbled cortical-white matter border on MRI), hydrocephalus, scattered small periventricular heterotopia and subependymal hemorrhages and calcifications, z-shaped brainstem, and in addition an occipital encephalocele, vermian agenesis, and an elongated and thick tectum (tectocerebellar dysraphia). CONCLUSIONS: The novel association of cobblestone malformation with tectocerebellar dysraphia as part of WWS is characteristic of the homozygous c.743C > del frameshift mutation in the DAG1 gene.