No abstract

miRNAs, the smallest nucleotide molecules able to regulate gene expression at post transcriptional level, are found in both animals and plants being involved in fundamental processes for growth and development of living organisms. The number of miRNAs has been hypothesized to increase when some organisms specialized the process of mastication and grinding of food. Further to the vertical transmission, miRNAs can undergo horizontal transmission among different species, in particular between plants and animals. In the last years, an increasing number of studies reported that miRNA passage occurs through feeding, and that in animals, plant miRNAs can survive the gastro intestinal digestion and transferred by blood into host cells, where they can exert their functions modulating gene expression. The present review reports studies on miRNAs during evolution, with particular focus on biogenesis and mechanisms regulating their stability in plants and animals. The different biogenesis and post biogenesis modifications allow to discriminate miRNAs of plant origin from those of animal origin, and make it possible to better clarify the controversial question on whether a possible cross-kingdom miRNA transfer through food does exist. The majority of human medicines and supplements derive from plants and a regular consumption of plant food is suggested for their beneficial effects in the prevention of metabolic diseases, cancers, and dietary related disorders. So far, these beneficial effects have been generally attributed to the content of secondary metabolites, whereas mechanisms regarding other components remain unclear. Therefore, in light of the above reported studies miRNAs could result another component for the medical properties of plants. miRNAs have been mainly studied in mammals characterizing their sequences and molecular targets as available in public databases. The herein presented studies provide evidences that miRNA situation is much more complex than the static situation reported in databases. Indeed, miRNAs may have redundant activities, variable sequences, different methods of biogenesis, and may be differently influenced by external and environmental factors. In-depth knowledge of mechanisms of synthesis, regulation and transfer of plant miRNAs to other species can open new frontiers in the therapy of many human diseases, including cancer.

Background: Taxol is an effective antineoplastic agent, originally extracted from the bark of Taxus brevifolia with a low yield. Many attempts have been made to produce Taxol by chemical synthesis, semisynthesis and plant tissue cultures. However, to date, the availability of this compound is not sufficient to satisfy the commercial requirements. The aim of the present work was to produce suspension cell cultures from plants not belonging to Taxus genus and to verify whether they produced Taxol and taxanes. For this purpose different explants of hazel (Corylus avellana species) were used to optimize the protocol for inducing in vitro callus, an undifferentiated tissue from which suspension cell cultures were established.

© F e r r a t a S t o r t i F o u n d a t i o nderived from co-culture of monocytes and autologous leukemic cells are characterized by a gene expression profile typical of cells with dysregulated immunocompetence which could be relevant in the context of the acquired immunodeficiency commonly found in CLL patients. 12Whether NLC represent CLL-specific tumor-associated macrophages, as recently suggested, 13 is still debated. We have recently reported that hepatocyte growth factor (HGF), together with CXCL12, is produced at high levels by stromal cells and is capable of prolonging the survival of CLL cells which are positive for the HGF receptor, c-MET.14 HGF is a multifunctional cytokine that induces multiple biological responses in target cells, including adhesion, motility, growth, survival and morphogenesis by activating its tyrosine kinase receptor, c-MET. 15,16 In normal individuals, HGF is constitutively produced by fibroblast-like stromal cells in lymphoid tissue and by follicular dendritic cells within the germinal center microenvironment. 15,17,18 NLC are present in the lymph nodes of CLL patients, where they are interspersed with stromal, dendritic and T cells to form proliferation centers. 19 The intriguing finding that HGF levels are higher in sera from CLL patients than from normal controls, 20 together with a still undefined pattern of effects induced by HGF on myelomonocytic cells, prompted us to determine c-MET expression on NLC and on monocytes-macrophages as well as investigate potential downstream events caused by the interaction between HGF and c-MET. MethodsThis study was approved by the review board of the IRCCS AOU San Martino -IST, Genoa, Italy. Full details are provided in the Online Supplementary Methods file. Cell preparationHeparinized blood or bone marrow samples were taken from CLL patients untreated for at least 3 months. The patients' characteristics are summarized in Online Supplementary Table S1. NLC were derived and characterized as described below and in the Online Supplementary Methods. CD14 + monocytes were purified from patients or healthy donors by magnetic beads. The human monocytic cell line THP-1 was utilized in selected experiments. Fluorescence microscopy and flow cytometryNLC or fresh monocytes from CLL or normal donors were challenged with antibodies against c-MET, indoleamine 2,3-dioxygenase (IDO), vimentin, CD68, interleukin (IL)-10, CD14, CXCR4, CD163 and pSTAT3 TYR705 and analyzed by immunofluorescence or flow cytometry. The quantification of pSTAT3 immunopositive cells area is described in detail in the Online Supplementary Methods. Analysis of STAT3 and pSTAT3 activation by western blottingWestern blotting was used to evaluate STAT3, pSTAT3 and bactin in monocytes from normal or CLL donors and in NLC with or without HGF treatment. Immunohistochemistry and immunofluorescence analysis of lymph node and bone marrow biopsiesTissue sections were probed with anti-human c-MET, -IDO, -vimentin, -CD68, and -CD163. 3,3'-Diaminobenzidine (DAB) substrate chromogen...

Drug resistance is the major obstacle in successfully treating high-risk neuroblastoma. The aim of this study was to investigate the basis of etoposide-resistance in neuroblastoma. To this end, a MYCN-amplified neuroblastoma cell line (HTLA-230) was treated with increasing etoposide concentrations and an etoposide-resistant cell line (HTLA-ER) was obtained. HTLA-ER cells, following etoposide exposure, evaded apoptosis by altering Bax/Bcl2 ratio. While both cell populations shared a homozygous TP53 mutation encoding a partially-functioning protein, a mono-allelic deletion of 13q14.3 locus, where the P53 inducible miRNAs 15a/16-1 are located, and the consequent miRNA down-regulation were detected only in HTLA-ER cells. This event correlated with BMI-1 oncoprotein up-regulation which caused a decrease in p16 tumor suppressor content and a metabolic adaptation of HTLA-ER cells. These results, taken collectively, highlight the role of miRNAs 15a/16-1 as markers of chemoresistance.