SiRNA-mediated knockdown against NUF2 suppresses tumor growth and induces cell apoptosis in human glioma cells.

Glioma is one of the most commonly malignant brain tumors. Current therapies for glioma have failed to achieve satisfactory results, which necessitates the development of novel molecular therapies. In the current study, we aimed to investigate the role of NUF2 (Ndc80 kinetochore complex component) in glioma cell growth and assessed the possible mechanisms underlying NUF2-mediated glioma development. The lentivirus-based short hairpin RNA-expressing vectors were constructed and transfected into U87 and U251 cells. Real time PCR and western blot were performed for expression level determination. Annexin V-FITC/PI flow cytometric assay was conducted to determine apoptotic cell proportions. Cell viability in vitro and tumorgenic ability in vivo were assessed by MTT assay and a nude mouse xenograft, respectively. We found that NUF2 was overexpressed in glioma tissues and differentially expressed in a series of glioma cell lines. Depletion of NUF2 by short-hairpin RNA inhibited cell growth in vitro and in vivo. Furthermore, NUF2 depletion-induced growth inhibition was associated with cell cycle arrest and apoptosis. Aberrant expressions of cell cycle regulators and apoptosis-related proteins further confirmed that NUF2 depletion induced cell cycle arrest and apoptosis. In all, our results indicate that siRNA-mediated knockdown against NUF2 may be a promising therapeutic method for the treatment of glioma.

Mechanism of RET gene mediated EGFR signaling pathway on epithelial-mesenchymal transition, proliferation and apoptosis of papillary thyroid carcinoma cells.

OBJECTIVE: To explore the mechanism of RET gene mediated EGFR signaling pathway on the epithelial-mesenchymal transition (EMT), proliferation and apoptosis of papillary thyroid carcinoma (PTC) cells. PATIENTS AND METHODS: PTC TPC-1 cells and human normal thyroid follicular epithelial cells Nthy-ori 3-1 were collected to identify the expression of RET in PTC. Seven groups were divided according to different transfection protocols, including blank group, negative control group, si-RET group, oe-RET group, AG-490 group, NSC 228155 group, and si-RET + NSC 228155 group. After transfection, qRT-PCR was used to identify whether the transfection was successful or not. qRT-PCR and Western blot were performed to detect the mRNA and protein expressions of RET, EGFR signaling pathway related genes, and EMT related genes. Cell migration, invasion, proliferation and apoptosis abilities were further detected by CCK8, cell scratch, transwell and flow cytometry assays, respectively. RESULTS: RET gene was highly expressed in PTC cells (p<0.05). Compared with blank group, oe-RET group and NSC 228155 group had activated EGFR signaling pathway manifesting in the increased expression of EGFR, p-Src, p-FAK, accelerated EMT showing in the increased expression of N-cadherin and Vimentin expression, but decreased E-cadherin expression, increased cell migration, invasion and proliferation, while decreased apoptosis (all p<0.05); si-RET group and AG-490 group had inhibited activation of EGFR signaling pathway, suppressed EMT, decreased cell migration, invasion and proliferation, while increased apoptosis (all p<0.05); while no evident difference was found in si-RET + NSC 228155 group (all p>0.05). Meanwhile, compared with si-RET group, si-RET + NSC 228155 group showed activated EGFR signaling pathway, accelerated EMT, increased abilities of cell migration, invasion and proliferation, while decreased apoptosis (all p<0.05). CONCLUSIONS: RET gene is highly expressed in PTC acting as an oncogene. Silencing RET gene expression may inhibit the invasion and promote the apoptosis of PTC cells by inhibiting the activation of EGFR signaling pathway and mediating the process of EMT. It suggests that RET may offer the possibility of a promising therapeutic target for the treatment of PTC on the basis of the explored mechanism.

Identification of novel mutations in MLC1 responsible for megalencephalic leukoencephalopathy with subcortical cysts.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an inherited neurologic disorder with macrocephaly before the age of one and slowly progressive deterioration of motor functions. Magnetic resonance imaging shows diffusely abnormal and swollen white matter of the cerebral hemispheres and the presence of subcortical cysts in the anterior-temporal region and often also in the frontoparietal region. Mutations in the MLC1 gene, encoding a putative membrane protein, have been recently identified as a cause for MLC. Here, we describe 14 new mutations in 18 patients. Two identified polymorphisms lead to alterations of amino acid residues. The role, suggested by others, of a mutation in the MLC1gene in catatonic schizophrenia and the possible function of the MLC1 protein as a cation channel are discussed.

Mutations of MLC1 (KIAA0027), encoding a putative membrane protein, cause megalencephalic leukoencephalopathy with subcortical cysts.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive disorder characterized by macrocephaly, deterioration of motor functions with ataxia, and spasticity, eventuating in mental decline. The brain appears swollen on magnetic resonance imaging, with diffuse white-matter abnormalities and the invariable presence of subcortical cysts. MLC was recently localized on chromosome 22q(tel). We have narrowed down the critical region by linkage analysis of 11 informative families with MLC to a region of approximately 250 kb, containing four known genes. One family with two patients who were siblings did not display linkage between the MLC phenotype and any of the analyzed microsatellite markers on chromosome 22q(tel), suggesting genetic heterogeneity and the existence of at least a second MLC locus. The maximum two-point LOD score for the 11 families was 6.6 at recombination fraction .02. Twelve different mutations in seven informative and six uninformative families were found in one of the candidate genes, KIAA0027, which we renamed "MLC1." The gene encodes a putative membrane protein with eight predicted transmembrane domains. The patients of one family were compound heterozygotes for mutations that both introduced stop codons. The mutations further included frameshifts, splice-acceptor mutations, a putative splice-donor mutation, and amino acid substitutions of residues in predicted transmembrane domains. These data provide strong evidence that mutations of MLC1 cause the disease.