An RFC4/Notch1 signaling feedback loop promotes NSCLC metastasis and stemness

Nat Commun. 2021 May 11;12(1):2693. doi: 10.1038/s41467-021-22971-x.

Abstract

Notch signaling represents a key mechanism mediating cancer metastasis and stemness. To understand how Notch signaling is overactivated to couple tumor metastasis and self-renewal in NSCLC cells, we performed the current study and showed that RFC4, a DNA replication factor amplified in more than 40% of NSCLC tissues, directly binds to the Notch1 intracellular domain (NICD1) to competitively abrogate CDK8/FBXW7-mediated degradation of NICD1. Moreover, RFC4 is a functional transcriptional target gene of Notch1 signaling, forming a positive feedback loop between high RFC4 and NICD1 levels and sustained overactivation of Notch signaling, which not only leads to NSCLC tumorigenicity and metastasis but also confers NSCLC cell resistance to treatment with the clinically tested drug DAPT against NICD1 synthesis. Furthermore, together with our study, analysis of two public datasets involving more than 1500 NSCLC patients showed that RFC4 gene amplification, and high RFC4 and NICD1 levels were tightly correlated with NSCLC metastasis, progression and poor patient prognosis. Therefore, our study characterizes the pivotal roles of the positive feedback loop between RFC4 and NICD1 in coupling NSCLC metastasis and stemness properties and suggests its therapeutic and diagnostic/prognostic potential for NSCLC therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Animals
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / therapy
  • Cell Line, Tumor
  • Feedback, Physiological
  • Female
  • Gene Expression Regulation, Neoplastic*
  • HEK293 Cells
  • Humans
  • Kaplan-Meier Estimate
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / therapy
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Nude
  • Neoplasm Metastasis
  • Receptor, Notch1 / genetics*
  • Receptor, Notch1 / metabolism
  • Replication Protein C / genetics*
  • Replication Protein C / metabolism
  • Signal Transduction / genetics*
  • Xenograft Model Antitumor Assays / methods

Substances

  • RFC4 protein, human
  • Receptor, Notch1
  • Replication Protein C