Project description:We found frequent epigenetic silencing of microRNA-34b/c in human colorectal cancer. Introduction of miR-34b/c into a colorectal cancer cell line induced significant changes in gene expression profile. We also found overlap between the genes downregulated by miR-34b/c and those downregulated by DAC. Keywords: dose response A colorecal cancer cell line HCT116 was transfected with miR-34b or -c precursor or negative control. Also, HCT116 was treated with 5-aza-2'-deoxycytidine (DAC) or mock. Genes up- or downregulated by miR-34b/c and those by DAC was compared.
Project description:Epigenetic regulators have emerged as critical factors governing the biology of cancer. Here, in the context of melanoma, we show that RNF2 is prognostic, exhibiting progression-correlated expression in human melanocytic neoplasms. Through a series of gain of function and loss of function studies, we establish that RNF2 is oncogenic and pro-metastatic. Mechanistically, RNF2-mediated invasive behavior is dependent on its ability to mono-ubiquitinate H2AK119 at the promoter of LTBP2, resulting in silencing of this negative regulator of TGFβ signaling. In contrast, RNF2's oncogenic activity did not require its catalytic activity nor derives from its canonical gene repression function, rather RNF2 drives proliferation through direct transcriptional up-regulation of the cell cycle regulator CCND2. In summary, RNF2 regulates distinct biological processes in the genesis and progression of melanoma via distinct molecular mechanisms, underscoring the complex and multi-faceted actions of epigenetic regulators in cancer. RNF2 is overexpressed in immortalized human melanocytes HMEL-BRAFV600E to address impact of RNF2 overexpression in melanoma. GFP was overexpressed in HMEL-BRAFV600E cells as a control cell line. Expression profiling using microarray was performed and compared between RNF2 overexpressing versus GFP overexpressing HMEL-BRAFV600E cells.
Project description:Epigenetic regulators have emerged as critical factors governing the biology of cancer. Here, in the context of melanoma, we show that RNF2 is prognostic, exhibiting progression-correlated expression in human melanocytic neoplasms. Through a series of gain of function and loss of function studies, we establish that RNF2 is oncogenic and pro-metastatic. Mechanistically, RNF2-mediated invasive behavior is dependent on its ability to mono-ubiquitinate H2AK119 at the promoter of LTBP2, resulting in silencing of this negative regulator of TGFβ signaling. In contrast, RNF2's oncogenic activity did not require its catalytic activity nor derives from its canonical gene repression function, rather RNF2 drives proliferation through direct transcriptional up-regulation of the cell cycle regulator CCND2. In summary, RNF2 regulates distinct biological processes in the genesis and progression of melanoma via distinct molecular mechanisms, underscoring the complex and multi-faceted actions of epigenetic regulators in cancer. RNF2 is overexpressed in immortalized human melanocytes HMEL-BRAFV600E to address impact of RNF2 overexpression in melanoma and identify RNF2 target genes. ChIP was performed to identify RNF2 binding sites using antibody against the V5 tag.
Project description:To gain insights into the genetic profile of every stage of the melanoma progression pathway, and to determine to what extent these profiles are similar or distinct, we performed whole-genome expression profiling of tissue specimens representing normal skin, benign and atypical nevi, and early and advanced-stage melanomas. The results of this study provide first-time evidence that significant molecular changes occur distinctly at the border of/transition from melanoma in situ to primary melanoma, and that genes involved in mitotic cell cycle regulation and cell proliferation constitute the two leading categories of genes associated with these changes. Keywords: Stage comparative analysis
Project description:Epigenetic alterations play significant roles in the melanoma tumorigenesis and malignant progression. We profiled genome-wide promoter DNA methylation patterns of melanoma cells deribed from primary lesions of Radial Growrth phase (RGP) and Vertical Growth Phase (VGP), metastatic lesions, and primary normal melanocytes by interrogating 14,495 genes using Illumina bead chip technology. By comparative analysis of the promoter methylation profiles, we identified epigenetically silenced gene signatures that potentially associated with malignant melanoma progression. Bisulphite converted genomic DNA from a group of melanoma cells representing pathologic stages of melanoma progression (3 cell lines derived from RGP melanoma lesions, 4 cell lines derived from VGP lesions, and 3 melastatic melanomas) and normal human primary melanocytes isolated from lightly pigmented adult skin were hybridized to Illumina's Infinium HumanMethylation27 BeadChips
Project description:Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that resists current treatments. To test epigenetic therapy against this cancer we used the DNA demethylating drug 5-aza-2’-deoxycytidine (DAC) in a KrasLSL-G12D; p53LSL-R270H/+; Pdx1-cre; Brca1flex2/flex2 (KPC-Brca1) mouse model of aggressive stroma-rich PDAC. In untreated tumors, we found globally decreased 5-methyl-cytosine (5mC) in malignant epithelial cells and in cancer-associated myofibroblasts (CAFs), and increased amounts of 5-hydroxymethyl-cytosine (5HmC) in CAFs, in progression from pancreatic intraepithelial neoplasia (PanIN) to PDAC. DAC further reduced DNA methylation and slowed PDAC progression, markedly extending survival in an early treatment protocol and significantly though transiently inhibiting tumor growth when initiated later, without adverse side effects. Escaping tumors contained areas of sarcomatoid transformation with disappearance of CAFs. Mixing-allografting experiments and proliferation indices showed that DAC efficacy was due to inhibition of both the malignant epithelial cells and the stromal CAFs. Expression profiling and immunohistochemistry highlighted DAC-induction of STAT1 in the tumors, and DAC plus gamma-interferon produced an additive anti-proliferative effect on PDAC cells. DAC induced strong expression of the testis antigen DAZL in CAFs. These data show that DAC is effective against PDAC in vivo and provide a rationale for future studies combining hypomethylating agents with cytokines and immunotherapy. Treatment of a short-term explant culture of malignant epithelial cells from a KPC-Brca1 mouse pancreatic carcinoma, with 0.5 micromolar 5-aza-dC (decitabine; DAC) for 48 hours. The experiment includes 3 replicate plates untreated and 3 replicates treated.