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SCIRT lncRNA Restrains Tumorigenesis by Opposing Transcriptional Programs of Tumor-Initiating Cells

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posted on 2024-03-20, 15:12 authored by Sladjana Zagorac, Alex de Giorgio, Aleksandra Dabrowska, Mark Kalisz, Nuria Casas-Vila, Paul Cathcart, Angela Yiu, Silvia Ottaviani, Neta Degani, Ylenia Lombardo, Alistair Tweedie, Tracy Nissan, Keith W Vance, Igor Ulitsky, Justin Stebbing, Leandro Castellano

Abstract In many tumors, cells transition reversibly between slow-proliferating tumor-initiating cells (TIC) and their differentiated, faster-growing progeny. Yet, how transcriptional regulation of cell-cycle and self-renewal genes is orchestrated during these conversions remains unclear. In this study, we show that as breast TIC form, a decrease in cell-cycle gene expression and increase in self-renewal gene expression are coregulated by SOX2 and EZH2, which colocalize at CpG islands. This pattern was negatively controlled by a novel long noncoding RNA (lncRNA) that we named Stem Cell Inhibitory RNA Transcript (SCIRT), which was markedly upregulated in tumorspheres but colocalized with and counteracted EZH2 and SOX2 during cell-cycle and self-renewal regulation to restrain tumorigenesis. SCIRT specifically interacted with EZH2 to increase EZH2 affinity to FOXM1 without binding the latter. In this manner, SCIRT induced transcription at cell-cycle gene promoters by recruiting FOXM1 through EZH2 to antagonize EZH2-mediated effects at target genes. Conversely, on stemness genes, FOXM1 was absent and SCIRT antagonized EZH2 and SOX2 activity, balancing toward repression. These data suggest that the interaction of an lncRNA with EZH2 can alter the affinity of EZH2 for its protein-binding partners to regulate cancer cell state transitions. Significance: These findings show that a novel lncRNA SCIRT counteracts breast tumorigenesis by opposing transcriptional networks associated with cell cycle and self-renewal. See related commentary by Pardini and Dragomir, p. 535

History

Refereed

  • Yes

Volume

81

Issue number

3

Page range

580-593

Publication title

Cancer Research

ISSN

0008-5472

Publisher

American Association for Cancer Research (AACR)

Location

United States

File version

  • Published version

Language

  • eng

Item sub-type

Journal Article

Media of output

Print-Electronic

Affiliated with

  • School of Life Sciences Outputs