In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: Exosomes are 30-100 nm membrane vesicles of endocytic origin, mediating diverse biological functions including tumor cell invasion, cell-cell communication and antigen presentation through transfer of proteins, mRNAs and microRNAs. Recent evidence suggests that microRNAs can be released through ceramide-dependent secretory machinery regulated by neutral sphingomyelinase 2 (nSMase2) enzyme encoded by the smpd3 gene that triggers exosome secretion. However, whether exosome-mediated microRNA transfer plays any role in cell invasion remains poorly understood. Thus, the aim of this study was to identify the exosomal microRNAs involved in breast cancer invasion.', 'The expression level of endogenous and exosomal miRNAs were examined by real time PCR and the expression level of target proteins were detected by western blot. Scanning electron and confocal microscopy were used to characterize exosomes and to study its uptake and transfer. Luciferase reporter plasmids and its mutant were used to confirm direct targeting. Furthermore, the functional significance of exosomal miR-10b was estimated by invasion assay.', 'In this study, we demonstrate that microRNA carrying exosomes can be transferred among different cell lines through direct uptake. miR-10b is highly expressed in metastatic breast cancer MDA-MB-231 cells as compared to non-metastatic breast cancer cells or non-malignant breast cells; it is actively secreted into medium via exosomes. In particular, nSMase2 or ceramide promotes the exosome-mediated miR-10b secretion whereas ceramide inhibitor suppresses this secretion. Moreover, upon uptake, miR-10b can suppress the protein level of its target genes such as HOXD10 and KLF4, indicating its functional significance. Finally, treatment with exosomes derived from MDA-MB-231 cells could induce the invasion ability of non-malignant HMLE cells.\Question: Does exosome-mediated transfer of miR-10b promote cell invasion in breast cancer?
Together, our results suggest that a set of specific microRNAs may play an important role in modulating tumor microenvironment through exosomes. Thus, a better understanding of this process may aid in the development of novel therapeutic agents.

Context: Non-viral gene transfer efficiency is low as compared to viral vector systems. Here we describe the discovery of new drugs that are capable of enhancing non-viral gene transfer into mammalian cells using a novel two-stage screening procedure.', 'First, potential candidates are preselected from a molecular library at various concentrations by a semi-automated yeast transfection screen (YTS). The maximal transfection efficiency of every positive drug is subsequently determined in independent experiments at the optimal concentration and compared to the inhibitory effect of the drug on cell growth (IC50). In a subsequent mammalian cell transfection screen (MTS), the maximal transfection efficiency and the IC50 are determined for all preselected drugs using a human cell line and a luciferase reporter gene construct.', 'Employing our novel system we have been able to identify a new class of transfection enhancers, the tricyclic antidepressants (i.e. doxepin, maprotiline, desipramine and amoxapine). All positive drugs enhanced gene transfer in both yeast and human cell lines, but lower concentrations were sufficient for mammalian cells. With a triple combination of doxepin, amoxapine and chloroquine we obtained a transfection efficiency that exceeded that of chloroquine, one of the best-known transfection enhancers of mammalian cells, by nearly one order of magnitude.\Question: Does novel two-stage screening procedure lead to the identification of a new class of transfection enhancers?
Non-viral gene transfer efficiency can be increased significantly using new transfection enhancers that are identified by a novel, semi-automated two-stage screening system employing yeast cells in the first and specific human target cells in the second round.

Context: Tumor necrosis factor- converting enzyme (TACE) has been demonstrated to be involved in liver inflammation. However, the significance of TACE methylation in acute-on-chronic hepatitis B liver failure (ACHBLF) has not been demonstrated. This study aims to evaluate TACE methylation status in ACHBLF and determine its predictive value for prognosis.', 'Forty-five patients with ACHBLF, 80 with chronic hepatitisB (CHB) and 54 healthy controls (HCs) were enrolled. The methylation status of TACE promoter was determined by methylation-specific polymerase chain reaction. The TACE mRNA expression was determined by quantitative real-time polymerase chain reaction. The plasma levels of TACE, TNF-, sTNFRI, sTNFRII were measured by enzyme-linked immunosorbent assay.', 'TACE methylation was significantly lower in patients with ACHBLF than those with CHB ((2)=24.69, P<0.01) and HCs ((2)=35.93, P<0.01). Meanwhile, TACE methylation was significantly lower in CHB patients than HCs ((2)=4.03, P<0.05). TACE methylation was significantly inversely associated with its mRNA expression (r=-0.68; P<0.01). The plasma levels of TACE, TNF-, sTNFRI, sTNFRII were significantly higher in patients with ACHBLF than those with CHB (P<0.05, respectively) and HCs (P<0.05, respectively). In patients with ACHBLF, significantly higher prothrombin activity, lower total bilirubin and MELD score were found in TACE methylated group than unmethylated group (P<0.05). ACHBLF patients with methylated TACE showed significantly better survival than those without (P<0.01).\Question: Does demethylation of tumor necrosis factor- converting enzyme predict poor prognosis in acute-on-chronic hepatitis B liver failure?
This study showed that demethylation of TACE promoter occurred in ACHBLF and might serve as a potential prognostic marker.