Spermine synthase and MYC cooperate to maintain colorectal cancer cell survival by repressing Bim expression

Yubin Guo, Qing Ye, Pan Deng, Yanan Cao, Daheng He, Zhaohe Zhou, Chi Wang, Yekaterina Y. Zaytseva, Charles E. Schwartz, Eun Y. Lee, B. Mark Evers, Andrew J. Morris, Side Liu, Qing Bai She

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Dysregulation of polyamine metabolism has been linked to the development of colorectal cancer (CRC), but the underlying mechanism is incompletely characterized. Here, we report that spermine synthase (SMS), a polyamine biosynthetic enzyme, is overexpressed in CRC. Targeted disruption of SMS in CRC cells results in spermidine accumulation, which inhibits FOXO3a acetylation and allows subsequent translocation to the nucleus to transcriptionally induce expression of the proapoptotic protein Bim. However, this induction is blunted by MYC-driven expression of miR-19a and miR-19b that repress Bim production. Pharmacological or genetic inhibition of MYC activity in SMS-depleted CRC cells dramatically induces Bim expression and apoptosis and causes tumor regression, but these effects are profoundly attenuated by silencing Bim. These findings uncover a key survival signal in CRC through convergent repression of Bim expression by distinct SMS- and MYC-mediated signaling pathways. Thus, combined inhibition of SMS and MYC signaling may be an effective therapy for CRC.

Original languageEnglish
Article number3243
JournalNature Communications
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2020

Bibliographical note

Publisher Copyright:
© 2020, The Author(s).

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy

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