MiR-4299 suppresses non-small cell lung cancer cell proliferation, migration and invasion through modulating PTEN/AKT/PI3K pathway.

OBJECTIVE: The aim of the present study was to investigate clinical significances and biological roles of miR-4299 in non-small cell lung cancer (NSCLC) PATIENTS AND METHODS: Expression of miR-4299 in NSCLC tissues and matched non-tumor tissues was determined by quantitative real-time PCR (qRT-PCR). The correlations between miR-4299 expression and clinicopathological characteristics and prognosis were also analyzed. MTT assay and Transwell assay were performed to determine the proliferation, migration and invasion. Western blotting was used to examine the expressing patterns of PTEN/AKT/PI3K signaling pathway-related proteins. RESULTS: We found that the expression level of miR-4299 was downregulated in NSCLC tissues and cell lines. Low miR-4299 expression was positively correlated with TNM stage (p=0.002), histological grade (p=0.002) and lymph node metastasis (p=0.028). Moreover, Kaplan-Meier survival analysis showed that the patients with low miR-4299 expression had shorter survival time than those with high miR-4299 expression (p=0.0011). More importantly, multivariate analysis suggested that decreased miR-4299 expression was a poor independent prognostic predictor for NSCLC patients (p=0.009). Functionally, overexpression of miR-4299 inhibited the proliferation, migration and invasion in A549 cells. Mechanistically, the results of Western blot showed that miR-4299 exhibited its tumor-suppressive role by modulating PTEN/AKT/PI3K signaling pathway. CONCLUSIONS: We firstly indicated that miR-4299 may be a candidate independent marker for NSCLC prognosis and suppressed the progression of NSCLC by modulating the activation of PTEN/AKT/PI3K signaling pathway, suggesting that miR-4299 could be a potential target for developing therapies in treating NSCLC.

Evaluation of the application of high volume hemofiltration in sepsis combined with acute kidney injury.

OBJECTIVE: To investigate the safety and effectiveness of the application of high-volume hemofiltration (HVHF) in children with sepsis combined with acute kidney injury. PATIENTS AND METHODS: A total of 76 child patients were enrolled and randomly divided equally (n=38) into control and the observation groups respectively. The control group received conventional volume hemofiltration (the ultrafiltration rate of 35-50 ml/kg/h), and the observation group received HVHF (50-100 ml/kg/h). RESULTS: The serum Interleukin-6 (IL-6), Tumor Necrosis Factor-a (TNF-α) and creatinine levels were significantly lower in the observation group than the control group at 6 h, 12 h, 24 h and 48 h of hemofiltration (p<0.05). The efficacy rate of treatment was improved. The mortality rate and incidence rate of complications were decreased, and the treatment course was significantly shortened (p<0.05). CONCLUSIONS: The application of HVHF in children with sepsis combined with acute kidney injury has a better safety and effectiveness.

Variants of ubiquitin-specific peptidase 24 play a crucial role in lung cancer malignancy.

Ubiquitin is a critical modifier regulating the degradation and function of its target proteins during posttranslational modification. Here we found that ubiquitin-specific peptidase 24 (USP24) is highly expressed in cell lines with enhanced malignancy and in late-stage lung cancer clinical samples. Studying single-nucleotide polymorphisms (SNPs) of USP24 using genomic DNA of lung cancer patients revealed an increase in SNP 7656C/T. When using RNA specimens instead of the genomic DNA of lung cancer patients, we found significant increases in the ratios of variants 930C/T and 7656T/C, suggesting that variants at these two sites are not only caused by the SNP of DNA but also by the RNA editing. USP24-930T and USP24-7656C increase USP24 expression levels by increasing RNA stability. Knocking down USP24 increased Suv39h1 level through a decrease in mouse double-minute 2 homolog levels, thus enhancing lysine-9 methylation of histone H3, and resulting in the prevention of lung cancer malignancy. In conclusion, as USP24 variant analysis revealed a higher ratio of variants in blood specimens of lung cancer patients than that in normal individuals, USP24-930T and USP24-7656C might be useful as diagnostic markers for cancer detection.

Sp1 phosphorylation by cyclin-dependent kinase 1/cyclin B1 represses its DNA-binding activity during mitosis in cancer cells.

Sp1 is important for the transcription of many genes. Our previous studies have shown that Sp1 is degraded in normal cell, but it is preserved in cancer cells during mitosis and exists a priori in the daughter cells, ready to engage in gene transcription and thereby contributes to the proliferation and survival of cancer cells. The mechanism by which Sp1 is preserved in cancer cells during mitosis remains unknown. In this study, we observed that Sp1 strongly colocalized with cyclin-dependent kinase 1 (CDK1)/cyclin B1 during mitosis. Moreover, we showed that Sp1 is a novel mitotic substrate of CDK1/cyclin B1 and is phosphorylated by it at Thr 739 before the onset of mitosis. Phospho-Sp1 reduced its DNA-binding ability and facilitated the chromatin condensation process during mitosis. Mutation of Thr739 to alanine resulted in Sp1 remaining in the chromosomes, delayed cell-cycle progression, and eventually led to apoptosis. Screening of Sp1-associated proteins during mitosis by using liquid chromatography/mass spectrometry indicated the tethering of Sp1 to myosin/F-actin. Furthermore, phospho-Sp1 and myosin/F-actin appeared to exist as a congregated ring at the periphery of the chromosome. However, at the end of mitosis and the beginning of interphase, Sp1 was dephosphorylated by PP2A and returned to the chromatin. These results indicate that cancer cells use CDK1 and PP2A to regulate the movement of Sp1 in and out of the chromosomes during cell-cycle progression, which may benefit cancer-cell proliferation.

Disruption of glucose homeostasis and induction of insulin resistance by elevated free fatty acids in human L02 hepatocytes.

Free fatty acids (FFA) have been implicated as an important causative link between obesity, insulin resistance, and Type 2 diabetes. However, the underlying mechanisms especially for FFA-mediated hepatic insulin resistance are not fully elucidated. Here, we investigated the impaired sites in insulin signaling pathways and mechanisms of insulin resistance induced by elevated FFA in L02 hepatocytes. L02 cells were cultured in Dulbecco's modified eagle medium containing various concentrations of palmitic acid (PA) for 24 h followed by 10(-7) mol/l insulin stimulation. In some experiments, cells were pre-treated with enzymatic inhibitor Wortmannin (10(-6) mol/l). Glucose levels in medium, cytosolic glycogen contents, and phosphoenolpyruvate carboxykinase (PEPCK) activity were measured. Protein level of insulin receptor substrate (IRS)-2 and phosphorylated Akt were detected by Western blot analysis. L02 cells treated with high levels of PA exhibited increased glucose levels, whereas hepatic glycogen contents were decreased in a dose-dependent manner as compared to the control cells. There was a significant attenuation of IRS- 2 protein expression in the cells cultured with PA, and Wortmannin intervention exhibited different IRS-2 protein level with or without PA treatment. In accordance with the reduced IRS-2 level, the insulin-stimulated phosphorylation of Akt was diminished in the PA-treated cells. Basal PEPCK activity and insulin- regulated PEPCK activity were overstimulated in the cells incubated with PA. These data indicate high levels of FFA can disrupt glucose homeostasis, inflict some defects in insulin signaling, and induce insulin resistance in L02 cells.

UV Resonance Raman Spectroscopic Identification of Titanium Atoms in the Framework of TS-1 Zeolite.

Framework titanium atoms in titanium-substituted silicalite (TS-1) can be identified by UV resonance Raman spectroscopy since the associated Raman bands at 1125, 530, and 490 cm(-1) (see figure) are observed only when the charge transfer transition associated with the framework Ti atoms is excited by a UV laser. Thus, framework Ti atoms can be distinguished from nonframework Ti atoms and other defect sites. This method can be applicable to identifying transition metal atoms in the frameworks of other molecular sieves.