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BackgroundThe formation of metastasis is the most common cause of death in patients with lung cancer. A major implement to understand the molecular mechanisms involved in lung cancer metastasis has been the lack of suitable models to address it. In this study, we aimed at establishing a highly metastatic model of human lung cancer and characterizing its metastatic properties and underlying mechanisms.MethodsThe human lung adeno-carcinoma SPC-A-1 cell line was used as parental cells for developing of highly metastatic cells by in vivo selection in NOD/SCID mice. After three rounds of selection, a new SPC-A-1sci cell line was established from pulmonary metastatic lesions. Subsequently, the metastatic properties of this cell line were analyzed, including optical imaging of in vivo metastasis, immunofluorescence and immunohistochemical analysis of several epithelial mesenchymal transition (EMT) makers and trans-well migration and invasion assays. Finally, the functional roles of fibronectin in the invasive and metastatic potentials of SPC-A-1sci cells were determined by shRNA analysis.ResultsA spontaneously pulmonary metastatic model of human lung adeno-carcinoma was established in NOD/SCID mice, from which a new lung cancer cell line, designated SPC-A-1sci, was isolated. Initially, the highly metastatic behavior of this cell line was validated by optical imaging in mice models. Further analyses showed that this cell line exhibit phenotypic and molecular alterations consistent with EMT. Compared with its parent cell line SPC-A-1, SPC-A-1sci was more aggressive in vitro, including increased potentials for cell spreading, migration and invasion. Importantly, fibronectin, a mesenchymal maker of EMT, was found to be highly expressed in SPC-A-1sci cells and down-regulation of it can decrease the in vitro and in vivo metastatic abilities of this cell line.ConclusionsWe have successfully established a new human lung cancer cell line with highly metastatic potentials, which is subject to EMT and possibly mediated by increased fibronectin expression. This cell line and its reproducible s.c. mouse model can further be used to identify underlying mechanisms of lung cancer metastasis.

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BackgroundGrowing evidence indicates that miR-200c is involved in carcinogenesis and tumor progression in non-small-cell lung cancer (NSCLC). However, its precise biological role remains largely elusive.MethodsThe functions of miR-200c and USP25 in migration/invasion and lung metastasis formation were determined by transwell and tail vein injection assays, respectively. The potential regulatory targets of miR-200c were determined by prediction tools, correlation with target protein expression, and luciferase reporter assay. The mRNA expression levels of miR-200c and USP25 were examined in NSCLC cell lines and patient specimens using quantitative reverse transcription-PCR. The protein expression levels of USP25 were examined in NSCLC cell lines and patient specimens using western blot and immunohistochemical staining.ResultsWe demonstrated that over-expression of miR-200c inhibited NSCLC cells migration, invasion, epithelial-mesenchymal transition (EMT) in vitro and lung metastasis formation in vivo. Further studies revealed that USP25 was a downstream target of miR-200c in NSCLC cells as miR-200c bound directly to the 3’-untranslated region of USP25, thus reducing both the messenger RNA and protein levels of USP25. Silencing of the USP25 gene recapitulated the effects of miR-200c over-expression. Clinical analysis indicated that miR-200c was negatively correlated with clinical stage, lymph node metastasis in NSCLC patients. Moreover, USP25 protein and mRNA level expressions were higher in NSCLC patients, compared to healthy control, and correlated with clinical stage and lymphatic node metastasis.ConclusionsThese findings indicate that miR-200c exerts tumor-suppressive effects for NSCLC through the suppression of USP25 expression and suggests a new therapeutic application of miR-200c in the treatment of NSCLC.

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In this study, we demonstrated that the effect of resveratrol on apoptosis is due to inhibiting miR-21 regulation of BCL-2 expression.

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A batch fermentation utilizing Saccharomyces cerevisiae BY4742 was conducted to determine the inhibitory effects of highly concentrated substrate and product levels on yeast. Experiments were performed to determine the largest dosage of substrate and the largest product concentration that the yeast could tolerate in a very high gravity fermentation process. The yeast's growth and fermentation activities were characterized by changes in the biomass and ethanol yield under different substrate and product concentrations during fermentation. All of the experiments were performed at a pH of 5.0 and a temperature of 35°C with a stirring rate of 180 r/min and a fermentation time of 96 h. Furthermore, five cycles of acclimatization were conducted to improve the yeast's tolerance to ethanol. Ethanol yield was maximized at 95% with a product concentration of 39 g/L and substrate dosage of 80 g/L. The system exhibited an obvious increase in cell growth and ethanol production with increasing substrate dosage up to a critical point of 160 g/L glucose (53 g/L ethanol fermented and an ethanol yield of 65%). Above this point, cell growth and ethanol production were inhibited with the final product concentration increasing only slightly with an increase in the initial substrate concentration. The end product (ethanol) was shown to be the primary factor inhibiting yeast growth and fermentation activity because the yeast would completely stop growing and fermenting when the initial exogenous ethanol concentration exceeded 70 g/L. The endogenous ethanol exerted a greater impact on yeast performance during anaerobic fermentation than exogenous ethanol. Five cycles of acclimatization significantly improved the yeast density, cell morphology, and ethanol production during very high gravity fermentation. The ethanol yield increased from 6% to 30% under an initial exogenous ethanol concentration of 60 g/L.