Project description:We sought to elucidate the molecular mechanisms whereby LIN28B functions by comparing the gene expression profile of cells constitutively expressing LIN28B to empty vector controls. Accordingly, we performed microarray analysis on total RNA isolated from empty vector LoVo and LIN28B-expressing LoVo colon cancer cell lines. Constitutive LIN28B expression was achieved in the LoVo (ATCC #CCL-229) colon cancer cell line via retroviral transduction of MSCV-PIG-LIN28B. Contol = empty vector MSCV-PIG.
Project description:This SuperSeries is composed of the following subset Series: GSE26334: Expression data from LoVo colon cancer lines +/- constitutive LIN28B expression GSE26335: Expression data from xenograft tumors derived from LoVo colon cancer lines +/- constitutive LIN28B expression Refer to individual Series
Project description:We sought to elucidate the molecular mechanisms whereby LIN28B functions by comparing the gene expression profile of cells constitutively expressing LIN28B to empty vector controls. Accordingly, we performed microarray analysis on total RNA isolated from empty vector LoVo and LIN28B-expressing LoVo colon cancer cell lines.
Project description:We sought to elucidate functions of LIN28B and potential mechanisms whereby it may promote metastasis by comparing the gene expression profile of LIN28B metastases to primary tumors. Accordingly, we performed microarray analysis on total RNA isolated from empty vector tumors, LIN28B-LoVo tumors, and LIN28B-LoVo metastases Constitutive LIN28B expression was achieved in the LoVo (ATCC #CCL-229) colon cancer cell line via retroviral transduction of MSCV-PIG-LIN28B. xenografts were produced via injection of 1x106 cells subcutaneously into the rear flanks of nude mice. Microarrays were conducted on primary tumors from empty vector and LIN28B-expressing cells, as well as metastases derived from primary tumors constitutively expressing LIN28B. (Note: metastases did not occur with empty vector tumors)
Project description:In this study, we investigated the role of LIN28 in intestinal tumor initiation and invasive progression. We generated animal models with just intestinal LIN28B overexpression, or in combination with Apcmin/+ background. The animals develop intestinal and colorectal tumors with histology ranging from adenoma to adenocarcinoma. total RNA isolated from mouse small intestinal tumors with LIN28B overexpression, or duodenum and colon Apcmin tumors and LIN28B;Apcmin tumors
Project description:The RNA binding protein Lin28b is highly expressed during embryogenesis but its expression declines in adult tissues, and aberrant expression of Lin28b is associated with tumour development and maintenance. Lin28b regulates the translation of several glycolytic and mitochondrial enzymes in order to enhance cellular metabolism and energy production. Lin28b is repressed by let-7 family microRNAs in a reciprocal negative regulatory circuitry where Lin28b supresses maturation of let-7. This circuitry obtains input from master regulators such as MYC that transcriptionally upregulates Lin28b, which is required for let-7 suppression and proliferation. Not much is known of how this circuitry is regulated through transcription of the let-7 microRNAs. Here we show that the transcription factor C/EBPβ-LIP induces aerobic glycolysis and mitochondrial respiration reminiscent to cancer cell metabolism. By integrating transcriptome, proteome and metabolic flux analysis we reveal that this LIP-induced metabolic reprogramming is dependent on Lin28b and that LIP enhances Lin28b expression through transcriptional repression of the let-7 microRNA family. Transgenic mice overexpressing LIP have reduced levels of let-7 in bone marrow, skin and spleen, which is associated with induction of Lin28b and hyperplasia. This study establishes LIP as a regulator of the let-7/Lin28b regulatory circuitry and we hypothesize that the LIP-controlled let-7/Lin28b regulation is involved in the de-regulation of tissue homeostasis and tumourigenesis.
Project description:The diversity and complexity of the cancer transcriptome hold the potential to yield tumor-specific transcripts (TSTs) in cancer. We report a novel LIN28B variant, LIN28B-TST, which is specifically expressed in hepatocellular carcinoma (HCC) and many other cancer types. LIN28B-TST initiates from a de novo alternative transcription initiation site. We found that LIN28B-TST was expressed in HuH-7 HCC cells and NCI-H1299 lung cancer cells, while wild-type LIN28B (LIN28B-WT) was expressed in HEK-293T human embryo kidney cells.
Project description:Chromatin remodeling proteins are frequently dysregulated in human cancer, yet little is known about how they control tumorigenesis. Here, we uncover an epigenetic program mediated by the NAD+-dependent histone deacetylase Sirtuin 6 (SIRT6) that is critical for suppression of pancreatic ductal adenocarcinoma (PDAC), one of the most lethal malignancies. SIRT6 inactivation accelerates PDAC progression and metastasis via upregulation of Lin28b, a negative regulator of the let-7 microRNA. SIRT6 loss results in histone hyperacetylation at the Lin28b promoter, Myc recruitment, and pronounced induction of Lin28b and downstream let-7 target genes, HMGA2, IGF2BP1 and IGF2BP3. This epigenetic program defines a distinct subset representing 30-40% of human PDAC, characterized by poor prognosis and an exquisite dependence on Lin28b for tumor growth. Thus, we identify SIRT6 as an important PDAC tumor suppressor, and uncover the Lin28b pathway as a potential therapeutic target in a molecularlydefined PDAC subset. ChIP-Seq experiments to examine H3K56ac histone modifications in murine PDAC cells that are Sirt6 wild type (WT), Sirt6 knock-out (KO), and Sirt6 KO cells engineered to express Sirt6 WT (Sirt6 KO + Sirt6 WT Restored).