Stress granule-associated protein G3BP2 regulates breast tumor initiation

Proc Natl Acad Sci U S A. 2017 Jan 31;114(5):1033-1038. doi: 10.1073/pnas.1525387114. Epub 2017 Jan 17.

Abstract

Breast tumors contain tumorigenic cancer cells, termed "tumor-initiating cells" (TICs), which are capable of both replenishing themselves and giving rise to populations of nontumorigenic breast cancer cells (non-TICs). However, the molecular mechanisms responsible for breast tumor initiation remain poorly understood. Here we describe a chemical screening strategy to identify small molecules that enhance the effect of chemotherapeutic agents on TIC-enriched breast cancer cells. We identified proteins that interact with the lead compound C108, including the stress granule-associated protein, GTPase-activating protein (SH3 domain)-binding protein 2, G3BP2. G3BP2 regulates breast tumor initiation through the stabilization of Squamous cell carcinoma antigen recognized by T cells 3 (SART3) mRNA, which leads to increased expression of the pluripotency transcription factors Octamer-binding protein 4 (Oct-4) and Nanog Homeobox (Nanog). Our findings suggest that G3BP2 is important for the process of breast cancer initiation. Furthermore, these data suggest a possible connection between stress granule formation and tumor initiation in breast cancer cells.

Keywords: G3BP2; breast cancer; stress granule; tumor-initiating cells.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Antigens, Neoplasm / biosynthesis
  • Antigens, Neoplasm / genetics
  • Antineoplastic Agents / isolation & purification
  • Antineoplastic Agents / pharmacology
  • Breast Neoplasms / etiology*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / mortality
  • Carcinogenesis*
  • Carrier Proteins / antagonists & inhibitors
  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • Cell Line, Tumor
  • Cytoplasmic Granules / physiology
  • Drug Resistance, Neoplasm
  • Drug Screening Assays, Antitumor
  • Female
  • Gene Expression Regulation, Neoplastic
  • Heterografts
  • Humans
  • Kaplan-Meier Estimate
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Nanog Homeobox Protein / metabolism
  • Neoplasm Proteins / antagonists & inhibitors
  • Neoplasm Proteins / deficiency
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / physiology*
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Octamer Transcription Factor-3 / metabolism
  • Paclitaxel / pharmacology
  • RNA Interference
  • RNA, Messenger / metabolism
  • RNA, Neoplasm / metabolism
  • RNA, Small Interfering / genetics
  • RNA-Binding Proteins / biosynthesis
  • RNA-Binding Proteins / genetics
  • Small Molecule Libraries

Substances

  • Adaptor Proteins, Signal Transducing
  • Antigens, Neoplasm
  • Antineoplastic Agents
  • Carrier Proteins
  • G3BP2 protein, human
  • NANOG protein, human
  • Nanog Homeobox Protein
  • Neoplasm Proteins
  • Octamer Transcription Factor-3
  • POU5F1 protein, human
  • RNA, Messenger
  • RNA, Neoplasm
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • SART3 protein, human
  • Small Molecule Libraries
  • Paclitaxel