Endogenous tumor suppression provides a barrier against oncogenesis, but the molecular requirements of this process are not well understood. Here, we show that the dual specificity phosphatase PTEN, a gene almost universally altered in human tumors, silences the expression of survivin, an essential regulator of cell division and apoptosis in cancer. This pathway is independent of p53, involves active repression of survivin gene transcription, and is mediated by direct occupancy of the survivin promoter by FOXO1 and FOXO3a factors. Conditional deletion of PTEN in the mouse prostate causes deregulated induction of survivin before full-blown transformation in vivo, whereas expression of survivin and PTEN is inversely correlated in cancer patients. Therefore, silencing the survivin gene is an essential requirement of endogenous PTEN tumor suppression.
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http://dx.doi.org/10.1158/0008-5472.CAN-09-0584 | DOI Listing |
Transgenic Res
January 2025
Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20, Prague 4, Czech Republic.
Proto-oncogene KRAS, GTPase (KRAS) is one of the most intensively studied oncogenes in cancer research. Although several mouse models allow for regulated expression of mutant KRAS, selective isolation and analysis of transforming or tumor cells that produce the KRAS oncogene remains a challenge. In our study, we present a knock-in model of oncogenic variant KRAS that enables the "activation" of KRAS expression together with production of red fluorescent protein tdTomato.
View Article and Find Full Text PDFCancer Res
December 2024
Lunenfeld-Tanenbaum Research Institute, Toronto, Canada.
IDH-mutant low-grade gliomas (LGGs) are slow-growing brain tumors that frequently progress to aggressive high-grade gliomas that have dismal outcomes. In a recent study, Wu and colleagues provide critical insights into the mechanisms underlying malignant progression by analyzing single-cell gene expression and chromatin accessibility across different tumor grades. Their findings support a two-phase model: in early stages, tumors are primarily driven by oligodendrocyte precursor-like cells and epigenetic alterations that silence tumor suppressors like CDKN2A and activate oncogenes such as PDGFRA.
View Article and Find Full Text PDFKaohsiung J Med Sci
January 2025
Department of Urology, Tianjin First Central Hospital, Tianjin, China.
miR-155 exhibits variable expression in different tumors and fulfills diverse biological roles. However, specific molecular mechanisms by which miR-155-5p, which is under-expressed in prostate cancer (PCa), operates are yet to be elucidated. The role of the enhancer of zeste 2 (EZH2)/miR-155-5p axis in PCa was determined by using bioinformatics tools and performing luciferase reporter assay, chromatin immunoprecipitation PCR, CCK-8 assays, cell migration and invasion assays, RNA isolation, reverse transcription quantity (RT-qPCR) and Western blot.
View Article and Find Full Text PDFPancreatic cancer (PC) is one of the leading causes of cancer deaths, associated with a high risk of metastasis and mortality. The long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is highly expressed in multiple types of tumour tissues and may be associated with the growth of PC cells. In this study, we aimed to assess the role and possible mechanisms of MALAT1 in PC progression.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Oncology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
Metabolic reprogramming of tumor cells dynamically reshapes the distribution of nutrients and signals in the tumor microenvironment (TME), affecting intercellular interactions and resulting in metabolic immune suppression. Increased glucose uptake and metabolism are characteristic of many tumors. Meanwhile, the progression of colorectal carcinoma (CRC) relies on lipid metabolism.
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