Autophagy inhibition elicits emergence from metastatic dormancy by inducing and stabilizing Pfkfb3 expression

Nat Commun. 2019 Aug 14;10(1):3668. doi: 10.1038/s41467-019-11640-9.

Abstract

Breast cancer stem cells (BCSCs) are unique in their ability to undergo unlimited self-renewal, an essential process in breast cancer recurrence following metastatic dormancy. Emergent metastatic lesions were subjected to microarray analysis, which identified 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3) as a differentially expressed gene coupled to metastatic recurrence. Here, we report that elevated Pfkfb3 expression correlates with the appearance of aggressive breast cancers and reduces relapse-free survival, as well as enhances BCSC self-renewal and metastatic outgrowth. We observe an inverse relationship between Pfkfb3 expression and autophagy, which reduces Pfkfb3 expression and elicits cellular dormancy. Targeted depletion of Atg3, Atg7, or p62/sequestosome-1 to inactivate autophagy restores aberrant Pfkfb3 expression in dormant BCSCs, leading to their reactivation of proliferative programs and outgrowth. Moreover, Pfkfb3 interacts physically with autophagy machinery, specifically the UBA domain of p62/sequestosome-1. Importantly, disrupting autophagy and this event enables Pfkfb3 to drive dormant BCSCs and metastatic lesions to recur.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / genetics*
  • Autophagy-Related Protein 7 / metabolism
  • Autophagy-Related Proteins / metabolism
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Cell Self Renewal
  • Female
  • Humans
  • Mice
  • Neoplasm Metastasis
  • Neoplastic Stem Cells / metabolism*
  • Phosphofructokinase-2 / metabolism*
  • Sequestosome-1 Protein / metabolism
  • Ubiquitin-Conjugating Enzymes / metabolism

Substances

  • Autophagy-Related Proteins
  • Sequestosome-1 Protein
  • Ubiquitin-Conjugating Enzymes
  • PFKFB3 protein, human
  • PFKFB3 protein, mouse
  • Phosphofructokinase-2
  • Autophagy-Related Protein 7
  • ATG3 protein, human
  • Atg3 protein, mouse