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Comaills, Valentine

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Comaills

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Valentine

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Comaills, Valentine

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    Publication
    SETD1A modulates cell cycle progression through a miRNA network that regulates p53 target genes
    (Nature Pub. Group, 2015) Tajima, Ken; Yae, Toshifumi; Javaid, Sarah; Tam, Oliver; Comaills, Valentine; Morris, Robert; Wittner, Ben; Liu, Mingzhu; Engstrom, Amanda; Takahashi, Fumiyuki; Black, Joshua C.; Ramaswamy, Sridhar; Shioda, Toshihiro; Hammell, Molly; Haber, Daniel; Whetstine, Johnathan; Maheswaran, Shyamala
    Expression of the p53-inducible antiproliferative gene BTG2 is suppressed in many cancers in the absence of inactivating gene mutations, suggesting alternative mechanisms of silencing. Using a shRNA screen targeting 43 histone lysine methyltransferases (KMTs), we show that SETD1A suppresses BTG2 expression through its induction of several BTG2-targeting miRNAs. This indirect but highly specific mechanism, by which a chromatin regulator that mediates transcriptional activating marks can lead to the downregulation of a critical effector gene, is shared with multiple genes in the p53 pathway. Through such miRNA-dependent effects, SETD1A regulates cell cycle progression in vitro and modulates tumorigenesis in mouse xenograft models. Together, these observations help explain the remarkably specific genetic consequences associated with alterations in generic chromatin modulators in cancer.
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    Expression of β-globin by cancer cells promotes cell survival during blood-borne dissemination
    (Nature Publishing Group, 2017) Zheng, Yu; Miyamoto, David; Wittner, Ben; Sullivan, James; Aceto, Nicola; Jordan, Nicole Vincent; Yu, Min; Karabacak, Nezihi; Comaills, Valentine; Morris, Robert; Desai, Rushil; Desai, Niyati; Emmons, Erin; Milner, John D.; Lee, Richard; Wu, Chin-Lee; Sequist, Lecia; Haas, Wilhelm; Ting, David; Toner, Mehmet; Ramaswamy, Sridhar; Maheswaran, Shyamala; Haber, Daniel
    Metastasis-competent circulating tumour cells (CTCs) experience oxidative stress in the bloodstream, but their survival mechanisms are not well defined. Here, comparing single-cell RNA-Seq profiles of CTCs from breast, prostate and lung cancers, we observe consistent induction of β-globin (HBB), but not its partner α-globin (HBA). The tumour-specific origin of HBB is confirmed by sequence polymorphisms within human xenograft-derived CTCs in mouse models. Increased intracellular reactive oxygen species (ROS) in cultured breast CTCs triggers HBB induction, mediated through the transcriptional regulator KLF4. Depletion of HBB in CTC-derived cultures has minimal effects on primary tumour growth, but it greatly increases apoptosis following ROS exposure, and dramatically reduces CTC-derived lung metastases. These effects are reversed by the anti-oxidant N-Acetyl Cysteine. Conversely, overexpression of HBB is sufficient to suppress intracellular ROS within CTCs. Altogether, these observations suggest that β-globin is selectively deregulated in cancer cells, mediating a cytoprotective effect during blood-borne metastasis.