Deregulation of microRNA (miRNA) expression has been documented in diffuse large B-cell lymphoma (DLBCL). However, the impact of miRNAs and their machinery in DLBCL is not fully determined. Here, we assessed the role of miRNA expression and their processing genes in DLBCL development. Using microarray and RT-qPCR approaches, we quantified global miRNAs and core components of miRNA-processing genes expression in 75 DLBCLs (56 de novo and 19 transformed) and 10 lymph nodes (LN). Differential miRNA signatures were identified between DLBCLs and LNs, or between the de novo and transformed DLBCLs. We also identified subsets of miRNAs associated with germinal center B-cell phenotype, BCL6 and IRF4 expression, and clinical staging. In addition, we showed a significant over-expression of TARBP2 in de novo DLBCLs as compared with LNs, and decreased expression of DROSHA, DICER, TARBP2 and PACT in transformed as compared with de novo cases. Interestingly, cases with high TARBP2 and DROSHA expression had a poorer chemotherapy response. We further showed that TARBP2 can regulate miRNA-processing efficiency in DLBCLs, and its expression inhibition decreases cell growth and increases apoptosis in DLBCL cell lines. Our findings provide new insights for the understanding of miRNAs and its machinery in DLBCL.

Background Platelets can synthesize proteins upon activation. Platelets contain a number of microRNAs (miRNA) and a fully functional miRNA effector machinery. It is, however, unclear if platelet miRNAs can regulate protein synthesis of platelets, and whether the regulation may produce a physiological impact. Objectives To investigate if and how platelet miRNAs regulate de novo syntheses of angiogenic regulators and subsequently modulate platelet angiogenic activities. Methods and Results Microarray-based miRNA profiling showed that thrombin stimulation in vitro down- or up-regulated a number of platelet miRNAs, both in the total platelet miRNAs and in Ago2-associated miRNAs. Among those altered miRNAs, miR-27b was down-regulated in both the total and Ago2-immunoprecipitated miRNA profiles of platelets, which was confirmed by reverse transcription-quantitative PCR (RT-qPCR). Using western blotting assays, we showed that thrombin induced platelet de novo synthesis of thrombospondin-1, and that the level of thrombospondin-1 synthesis could reach a level of 3-5-fold higher than that before thrombin stimulation. With either the platelet precursor megakaryocyte cell line MEG-01 cells or mature platelets, we demonstrated that transfection of miR-27b mimic, but not the negative control of miRNA mimic, markedly reduced thrombospondin-1 protein levels. The latter subsequently enhanced platelet-dependent endothelial tube formation on matrigel. Conclusions Thrombin stimulation in vitro reduces platelet miR-27b levels that may markedly enhance thrombin-evoked platelet de novo synthesis of thrombospondin-1. Elevation of platelet miR-27b by transfection inhibits thrombospondin-1 synthesis, and subsequently enhances platelet pro-angiogenic activities. Hence, platelet activation-dependent reduction of miR-27b levels may represent a novel negative regulatory mechanism of platelet angiogenic activities.

It has been suggested that beneficial bacteria may stimulate wound healing. The aim was to investigate the effect of topical applications of probiotic lactobacilli on the healing of standardised oral wounds. This pilot study employed a randomised, placebo-controlled, double-blind cross-over design. Standardised biopsies were punched in the oral mucosa of 10 healthy volunteers, with and without exposure to two strains of Lactobacilli reuteri administrated as lozenges and topical oil. The healing was scored clinically after 2, 5 and 8 days. The amount of exudate was quantified through filter papers and the levels of selected cytokines and chemokines were determined with multiplex immunoassays. Saliva samples were collected before the biopsy and after healing for determination of oxytocin with ELISA. Subjectively perceived pain and discomfort was reported through a daily logbook. There was a clear tendency of improved healing in test group at the 2-and 5-day check-ups but the difference compared with the placebo intervention was not statistically significant (P=0.08). Higher but non-significant expressions of the tumour necrosis factor (TNF) superfamily ligand members 13 (APRIL) and 13B (BAFF), as well as the chemokine interleukin 8 (IL-8), were displayed in wound exudates from the probiotic group as compared with placebo, particularly after 5 and 8 days. The salivary levels of oxytocin were significantly lower (P<0.05) in the placebo group at the 8-day follow-up. The mean number of days with pain and/or discomfort after the biopsies was similar in both groups. No side-effects were reported. The findings of this pilot study justify a larger clinical trial to elucidate the possible role of probiotic supplements on oral wound healing.

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Chronic inflammation is a well-characterized driver of cancer in the skin and other epithelial organs; however, the mechanism underlying the development of cancer-promoting chronic inflammation is unknown. We previously showed chronic allergic contact dermatitis (ACD) is a type 2 inflammatory disease and potent inducer of squamous cell carcinoma in mice and humans. In contrast, acute ACD, a common skin inflammatory condition, is marked by type 1 inflammation, including T helper 1, cytotoxic T, and NK cells, which inhibit cancer development. The opposite effects of chronic versus acute ACD on cancer provide a unique paradigm to investigate how cancer-promoting chronic inflammation develops. To determine the mechanism underlying the transition from acute to chronic ACD, we examined the epithelium-derived cytokines, IL-33, TSLP, and IL-25, that are master drivers of type 2 inflammation in barrier organs. IL-33 expression markedly increased during the transition from acute to chronic ACD, initiating tumor-promoting, type 2 inflammation in chronic ACD. Mice lacking IL-33 or IL-33 receptor (ST2) were protected from ACD-induced skin cancer compared to wild-type controls and IL-33 was required for the progression of inflammatory bowel disease-induced colorectal cancer. Notably, IL-33s direct effect on T regulatory cells was required for the development of a cancer-promoting immune environment in the skin and colon. Our findings elucidate a novel mechanism underlying the formation of a tumorinitiating immune environment in chronic inflammatory diseases and yield novel targets for cancer treatment and prevention in chronic inflammatory contexts.

all animal works has been obtained from the Institutional Animal Care and Use Committee, Academia Sinica. Results and discussions Galectin-4 was upregulated during the development of castration resistance and metastasis. High expression of galectin-4 in PCa cells exhibited castration resistance, tumor-regenerating stem-like cells, expressed SOX9 and ALDH1A1, and ability to colonise distant metastases. We identify a feed-forward signalling pathway by which galectin-4 signalling through RTK-Myc axis upregulated gene transcription of enzymes in a specific O-glycosylation pathway and the biosynthesis of their substrates, thus altered the cellular modification of O-glycosylation, and bolstered castration resistance and metastasis. These coordinated effects conferred more and more binding sites for galectin-4 and amplified the RTKs signalling, implicating crosstalk mechanisms to activate androgen receptor signalling and drive the PCa progression. Conclusion MYC regulates oncofetal O-glycosylation in RTKs thus primes the cells for binding to galectin-4 and downstream signalling, which promotes PCa castration resistance, metastasis, and clinically poor survival. PO-253ABSTRACT WITHDRAWN Introduction Background and aim Merkel cell carcinoma (MCC) is an aggressive type of skin cancer. About 80% of MCCs harbour integrated Merkel cell polyomavirus (MCV) genome with a mutation in the large T (LT) gene. MCV T-antigens are required for neoplastic transformation and maintenance of cell growth. however the molecular mechanism by which the virus induces tumorigenesis remains unclear. In this study we aimed to identify and characterise functional role of MCV-regulated microRNAs in MCC. Material and methods We did silencing or ectopic expression of MCV T-antigens to identify specific miRNAs regulated by MCV T-antigens by RT-qPCR. The involvement of MCV Tantigens and miRNAs in autophagy was evaluated using LC3-II conversion, mRFP-EGFP-LC3 reporter and/or transmission electron microscopy. The targets of miRNAs were verified by western blot analysis and luciferase reporter assays. We also look for the DICER expression by western blot. Results and discussions We identified specific miRNAs regulated by MCV T-antigens. Using both gain-and loss-of-function experiments, we showed that MCV T-antigens and MCVregulated miRNAs (miR-375, miR-30a-5p and miR-30a-3p) could regulate autophagy. We further demonstrated that miR-375 could directly regulate ATG7 and SQSTM1, while both miR-30a-3p and miR-30a-5p could target BECN1. We also identified the MCV T-antigens regulates these miRNAs PO-254 MERKEL CELL POLYOMAVIRUS T-ANTIGEN REGULATE MICRORNAS POST-TRANSCRIPTIONALLY THROUGH DICER IN MERKEL CELL CARCINOMA