MCM10 compensates for Myc-induced DNA replication stress in breast cancer stem-like cells

Cancer Sci. 2021 Mar;112(3):1209-1224. doi: 10.1111/cas.14776. Epub 2021 Jan 22.

Abstract

Cancer stem-like cells (CSCs) induce drug resistance and recurrence of tumors when they experience DNA replication stress. However, the mechanisms underlying DNA replication stress in CSCs and its compensation remain unclear. Here, we demonstrate that upregulated c-Myc expression induces stronger DNA replication stress in patient-derived breast CSCs than in differentiated cancer cells. Our results suggest critical roles for mini-chromosome maintenance protein 10 (MCM10), a firing (activating) factor of DNA replication origins, to compensate for DNA replication stress in CSCs. MCM10 expression is upregulated in CSCs and is maintained by c-Myc. c-Myc-dependent collisions between RNA transcription and DNA replication machinery may occur in nuclei, thereby causing DNA replication stress. MCM10 may activate dormant replication origins close to these collisions to ensure the progression of replication. Moreover, patient-derived breast CSCs were found to be dependent on MCM10 for their maintenance, even after enrichment for CSCs that were resistant to paclitaxel, the standard chemotherapeutic agent. Further, MCM10 depletion decreased the growth of cancer cells, but not of normal cells. Therefore, MCM10 may robustly compensate for DNA replication stress and facilitate genome duplication in cancer cells in the S-phase, which is more pronounced in CSCs. Overall, we provide a preclinical rationale to target the c-Myc-MCM10 axis for preventing drug resistance and recurrence of tumors.

Keywords: DNA replication stress; MCM; anticancer drug resistance; breast cancer; c-Myc; cancer stem cell; drug sensitivity/drug resistance-relating factors/gene expression analysis; oncogenes and tumor-suppressor genes; others; tumor spheroids.

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use
  • Breast / pathology
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • DNA Damage / drug effects
  • DNA Replication / drug effects
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / genetics
  • Female
  • Humans
  • Minichromosome Maintenance Proteins / genetics
  • Minichromosome Maintenance Proteins / metabolism*
  • Neoplasm Recurrence, Local / genetics*
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / prevention & control
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / pathology*
  • Primary Cell Culture
  • Proto-Oncogene Proteins c-myc / antagonists & inhibitors
  • Proto-Oncogene Proteins c-myc / metabolism*
  • Spheroids, Cellular
  • Tumor Cells, Cultured
  • Up-Regulation

Substances

  • Antineoplastic Agents
  • MCM10 protein, human
  • MYC protein, human
  • Proto-Oncogene Proteins c-myc
  • Minichromosome Maintenance Proteins