ABSTRACT: SW480R is an APC mut, KRAS mut, P53 mut CRC cell line. PROX1 transcription factor, target of Wnt pathway in CRC, is our protein of interest.SW480R cells are PROX1 positive. We suppressed through siRNA transfection the expression of PROX1 protein or non-targeting siRNA, using two different siRNA. Afterwards we compared the transcriptional program of the SW480-PROX1si and SW480R-CTRsi cells growing in monolayer in vitro.
Project description:DLD1 is an APC mut, KRAS mut, P53 mut CRC cell line. PROX1 transcription factor, target of Wnt pathway in CRC, is our protein of interest.DLD1 cells are PROX1 negative. We overexpressed through lentiviral expression PROX1 protein or the empty vector psd44, through selection of the cells in puromycin resistance. Afterwards we compared the transcriptional program of the DLD1-PROX1 and DLD1-Control cells growing in monolayer in vitro.
Project description:Analysis of CGTH-W-1 follicular thyroid carcinoma cells transcriptome following 48 hrs siRNA-mediated depletion of PROX1. PROX1 is a homeobox transcription factor. PROX1 depletion decreases migratory ability, motility and invasivness and induces profound cytoskeleton changes of CGTH-W-1 cells. Results provide insight into the role of PROX1 in the thyroid cancer. Three biological replicates for a given condition
Project description:Cell fate plasticity enables development, yet unlocked plasticity is a cancer hallmark. Regulating cell identity requires gene activation and repression. While master regulators induce lineage-specific genes to restrict plasticity, it remains unclear whether unwanted plasticity is actively suppressed by lineage-specific repressors. Here, we computationally predict so-called safeguard repressors for 18 cell types that block phenotypic plasticity lifelong. We validated hepatocyte-specific candidates using reprogramming, revealing that Prospero homeobox protein 1 (PROX1) enhanced hepatocyte identity by direct repression of alternate fate master regulators. In line with patient data, PROX1 overexpression in mice blocked initiation and progression of hepatocellular carcinoma and extended survival. Remarkably, Prox1 depletion caused hepatocyte fate loss in vitro, and promoted transdifferentiation of hepatocellular- to cholangio-carcinoma in vivo. Our findings provide mechanistic evidence for PROX1 as a hepatocyte-specific safeguard and support a model where individual cell type-specific repressors actively suppress plasticity throughout life to safeguard lineage choice and prevent disease.
Project description:Integrase CLIP-seq experiments were conducted on wild-type and eccentric HIV-1 virions generated in the presence of allosteric integrase inhibitors and IN K264/266A and R269/K273A mutations Integrase CLIP-seq experiments were conducted by immunoprecipitation of integrase-RNA complexes from fully formed mature and eccentric virus particles. Libraries of RNA molecules bound by integrase were generated and sequenced by Illumina Hi-Seq2000 and 2500 platforms.
Project description:Glioblastoma represents the most common and aggressive primary brain tumor type in adults. Stem cell regulatory pathways have been shown to be activated in gliomas supporting self-renewal, tumor maintenance and survival under stress. Glioblastoma stem-like phenotype, cell motility and tumor cell heterogeneity are considered significant hurdles to overcome for developing new treatment against these tumors. Transcription factor PROX1 has been associated with stem-like-phenotypes. Here, we overexpressed and suppressed PROX1 in glioma cell lines in order understand the gene expression regulated by this transcription factor.
Project description:The assembly of fission yeast pericentromeric heterochromatin and generation of small interfering RNAs (siRNAs) from noncoding centromeric transcripts are mutually dependent processes. How this interdependent positive feedback loop is first triggered is a fundamental unanswered question. Here we show that two distinct Argonaute (Ago1)-dependent pathways mediate small RNA generation. RNA-dependent RNA polymerase complex (RDRC) and Dicer act on specific noncoding RNAs to generate siRNAs by a mechanism that requires the slicer activity of Ago1 but is independent of pre-existing heterochromatin. In the absence of RDRC or Dicer, a distinct class of small RNAs, called primal small RNAs (priRNAs), associate with Ago1. priRNAs are degradation products of abundant transcripts, which bind to Ago1 and target antisense transcripts that result from bidirectional transcription of DNA repeats. Our results suggest that a transcriptome surveillance mechanism based on the random association of RNA degradation products with Argonaute triggers siRNA amplification and heterochromatin assembly within DNA repeats. small RNA profiling in wild type S. pombe cells and in 12 mutant cells
Project description:Oncogenic mutations in Kras initiate neoplastic transformation in the pancreas through a process that hijacks the activity of developmental regulators and induces an inflammatory microenvironment. We report that the homeodomain transcription factor Prox1 is a novel component of a progenitor signature that is activated in acinar cells undergoing dedifferentiation and ductal metaplasia conversion. Also, the conditional deletion of a single Prox1 allele markedly accelerates early transformation and significantly enhances features of inflammation in pancreatic tissues carrying a Kras oncogene. By using in vitro and in silico approaches, we demonstrate that Prox1 negatively regulates the expression of proinflammatory genes and genes implicated in malignant transformation in pancreatic cells. Microrrays were used to identify gene expression profiles and pathways that are differentially activated after enforced expression of PROX1 in the PROX1-negative human pancreatic ductal adenocarcinoma (PDAC) cell line Capan1. MSCV retroviral transduction was used to generate Capan1 cells that ectopically express PROX1 and selected for puromycin resistance. Three independent transductions with control virus (MSCV_puro) and 3 independent transductions with Prox1-cDNA virus (MSCV_PROX1_puro) were conducted for these experiments.
Project description:Colorectal carcinoma (CRC) progression is associated with an increase in PROX1+ tumor cells, which exhibit features of CRC stem cells and contribute to metastasis. Here, we aimed to provide a better understanding to the function of PROX1+ cells in CRC, investigating their progeny and their role in therapy resistance. PROX1+ cells in intestinal adenomas of ApcMin/+ mice expressed intestinal epithelial and CRC stem cell markers, and cells with high PROX1 expression could both self-renew tumor stem/progenitor cells and contribute to differentiated tumor cells. Most PROX1-lineage traced tumor cells were stem/progenitor cells, which can supply cells to multiple intestinal tumor cell lineages, whereas most lineage-traced LGR5+ tumor cells were enterocytes, indicating that PROX1+ and LGR5+ tumor stem cells have distinct differentiation programs. Although the PROX1+ tumor cells proliferated slower than PROX1- cells, irradiation increased the proportion of PROX1+ cells in human CRC cell lines, patient-derived organoids, and tumor xenografts. Furthermore, transcripts related to DNA damage repair (DDR) were enriched in PROX1+ vs. PROX1- cells in adenomas and in CRC tumor cells from patients. Experiments with PROX1 silencing and overexpression indicated that PROX1 expression enhances CRC cell colony formation following irradiation. PROX1 interacted with DDR proteins, including components of non-homologous end-joining (NHEJ) and base excision repair, and inhibition of NHEJ repair led to a decreased proportion of PROX1+ cells following irradiation. In conclusion, PROX1+ cells are irradiation-resistant tumor stem/progenitor cells capable of self-renewal and differentiation. DDR inhibitors could represent a strategy to target the treatment-resistant PROX1+ tumor stem cells.
Project description:Distinct classes of small RNAs are often selectively sorted to different Argonaute proteins. Various properties of small RNAs, such as length, terminal nucleotide, thermodynamic asymmetry and duplex mismatches, can impact sorting in different RNA silencing pathways in diverse eukaryotes. The developmentally regulated ~26-32 nt siRNAs, which are involved in programmed DNA elimination in Tetrahymena, show a strong bias for uracil at the 5' end. In this study, we analyzed loaded and unloaded populations of ~26-32 nt siRNAs by deep RNA sequencing. We show that the production process is the main determinant of size, whereas the 5' uracil bias is attributed not only to the process of loading siRNAs into the Argonaute protein Twi1p but also significantly to the initial processing of the siRNAs. We also show that both the loaded and the unloaded ~26-32 nt siRNAs have a strong bias for adenine as the 3rd base from the 3' terminus, suggesting that most of these siRNAs are direct Dicer products and little post-processing amplification of this class of siRNAs occurs. Further, we demonstrate that the siRNA-loading process in vivo can be deduced from the fraction of siRNAs with uracil as the first base. These findings provide biochemical bases for the attributes of ~26-32 nt siRNAs, which should help improve our understanding of their production and turnover in vivo. Examination of siRNA populations in wild-type and TWI1 KO Tetrahymena cells