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: To assess the effect of six different enteral diets on the gut barrier.', 'Laboratory study.', 'University hospital, Germany.', '70 Specific pathogen free female Crl:CDR BR rats.', 'For 7 days, 6 groups of rats were fed orally with standard chow (n = 15); total parenteral nutrition solution (oral TPN, n = 15); elemental diet (ED, n = 10); nutrient-defined diet (NDD, n = 10); or the NDD supplemented with uracil (NDD+uracil, n = 10), or fibre (NDD+fibre, n = 10).', 'Bacterial translocation to mesenteric lymph nodes, numbers of Gram negative enterobacteria and total aerobic bacteria in the caecum, and intestinal concentrations of secretory IgA.', 'The incidence of bacterial translocation was significantly increased in the groups given oral TPN, ED, NDD, and NDD+uracil compared with the group given chow. Only NDD+fibre resulted in a similar degree of translocation to that in the chow group. All groups in which there was increased translocation had a highly significant overgrowth of aerobic bacteria in the caecum, mainly by Gram negative enteric organisms. The secretory IgA concentration was reduced in the group that had been given oral TPN, and that in the ED and NDD+uracil groups was similar to that in the chow group. NDD and NDD+fibre were associated with higher intestinal concentrations of secretory IgA than chow.\Question: Is fibre an essential ingredient of enteral diets to limit bacterial translocation in rats?
Fibre-free enteral diets do not protect the gut antimicrobial barrier whatever else is in them. The superiority of early enteral as opposed to parenteral nutrition after injury may, therefore, not be the result of a specific protective effect on the gut barrier. The supplementation of commercial enteral diets with bulk fibre should be tested in clinical trials.

Context: Diosgenin is a steroidal sapogenin with estrogenic and antitumor properties. In order to elucidate the mechanism of its antiproliferative activity, we investigated its effects on the cell cycle and apoptosis in human chronic myelogenous leukemia K562 cells.', 'Cell viability was assessed via an MTT assay. Apoptosis was investigated in terms of nuclear morphology, DNA fragmentation, and phosphatidylserine externalization. Cell cycle analysis was performed via PI staining and flow cytometry (FCM). Western blotting and immunofluorescence methods were used to determine the levels of p53, cell cycle-related proteins and Bcl-2 family members. FCM was also used to estimate the changes in mitochondrial membrane potential (MMP), intracellular Ca2+ concentration and reactive oxygen species (ROS) generation.', 'Cell cycle analysis showed that diosgenin caused G2/M arrest independently of p53. The levels of cyclin B1 and p21Cip1/Waf1 were decreased, whereas cdc2 levels were increased. Subsequent apoptosis was demonstrated with the dramatic activation of caspase-3. A dramatic decline in intracellular Ca2+ concentration was observed as an initiating event in the process of cell cycle arrest and apoptosis, which was followed by the hyperpolarization and depolarization of MMP. Generation of ROS was observed in the progression of apoptosis. The antiapoptotic Bcl-2 and Bcl-xL proteins were downregulated, whereas the proapoptotic Bax was upregulated.\Question: Does diosgenin induce cell cycle arrest and apoptosis in human leukemia K562 cells with the disruption of Ca2+ homeostasis?

Diosgenin inhibits K562 cell proliferation via cell cycle G2/M arrest and apoptosis, with disruption of Ca2+ homeostasis and mitochondrial dysfunction playing vital roles.