Project description:As the leading cause of food-borne illness in the world, Salmonella have evolved a sophisticated machinery to alter host cell function to promote virulence and survival.In this study, we compare production of non-coding RNAs between Salmonella-infected cells and mock infection cells. Using Solexa deep sequencing, we detected a panel of 19-24nt Salmonella-derived non-coding RNA fragments with considerable large copy numbers in human colonic epithelial HT-29 cells following Salmonella infection.The fragment with the highest copy number, Sal-1, was further validated by both quantitative reverse transcription polymerase chain reaction (qRT-PCR) and northern blot. The generation of Sal-1 requires the infection of host cells by Salmonella, and the processing of the Sal-1 “primary” or “precursor” to the mature Sal-1 in Salmonella-infected cells is Dicer-independent but Argonaute 2 (Ago2)-dependent. Functionally, Sal-1 suppresses the expression of colonic epithelial cell endogenous inducible nitric oxide synthase (iNOS) via targeting its open reading frame and thus reduces the bacterial resistance of host cells.
Project description:As the leading cause of food-borne illness in the world, Salmonella have evolved a sophisticated machinery to alter host cell function to promote virulence and survival.In this study, we compare production of non-coding RNAs between Salmonella-infected cells and mock infection cells. Using Solexa deep sequencing, we detected a panel of 19-24nt Salmonella-derived non-coding RNA fragments with considerable large copy numbers in human colonic epithelial HT-29 cells following Salmonella infection.The fragment with the highest copy number, Sal-1, was further validated by both quantitative reverse transcription polymerase chain reaction (qRT-PCR) and northern blot. The generation of Sal-1 requires the infection of host cells by Salmonella, and the processing of the Sal-1 M-bM-^@M-^\primaryM-bM-^@M-^] or M-bM-^@M-^\precursorM-bM-^@M-^] to the mature Sal-1 in Salmonella-infected cells is Dicer-independent but Argonaute 2 (Ago2)-dependent. Functionally, Sal-1 suppresses the expression of colonic epithelial cell endogenous inducible nitric oxide synthase (iNOS) via targeting its open reading frame and thus reduces the bacterial resistance of host cells. Screening and identification of Salmonella-encoded microRNA-like RNA fragments
Project description:MORAB-003 significantly upregulated a number of genes involved in autophagic processing, including GABARAPL2, LC3II (MAP1LC3B), ATG3, ATG4B, and BECN1, while expression of the oncogenic factor PIK3C3 was downregulated. We used microarrays to detail the global programme of gene expression underlying growth inhibition of ovarian cancer cells treated with MORAB-003
Project description:Pancreatic ductal adenocarcinoma (PDAC) is a nearly uniformly lethal malignancy, with most patients facing an adverse clinical outcome. Given the pivotal role of aberrant Notch signaling in the initiation and progression of PDAC, we investigated the effect of MRK-003, a potent and selective γ-secretase inhibitor, in preclinical PDAC models. We used a panel of human PDAC cell lines, as well as patient-derived PDAC xenografts, to determine whether pharmacological targeting of the Notch pathway could inhibit pancreatic tumor growth and potentiate gemcitabine sensitivity. In vitro, MRK-003 treatment downregulated the canonical Notch target gene Hes-1, significantly inhibited anchorage independent growth, and reduced the subset of CD44+CD24+ and aldehyde dehydrogenase (ALDH)+ cells that have been attributed with tumor initiating capacity. Ex vivo pretreatment of PDAC cells with MRK-003 in culture significantly inhibited the subsequent engraftment in immunocompromised mice. In vivo, MRK-003 monotherapy significantly blocked tumor growth in 5 of 9 (56%) patient-derived PDAC xenografts. Moreover, a combination of MRK-003 and gemcitabine showed enhanced antitumor effects compared to gemcitabine alone in 4 of 9 (44%) PDAC xenografts. Baseline gene expression analysis of the treated xenografts indicated that upregulation of nuclear factor kappa B (NFκB) pathway components was associated with the sensitivity to single MRK-003, while upregulation in B-cell receptor (BCR) signaling and nuclear factor erythroid-derived 2-like 2 (NRF2) pathway correlated with response to the combination of MRK-003 with gemcitabine. The preclinical findings presented here provide further rationale for small molecule inhibition of Notch signaling as a therapeutic strategy in PDAC.