DRAM1 plays a tumor suppressor role in NSCLC cells by promoting lysosomal degradation of EGFR

Cell Death Dis. 2020 Sep 17;11(9):768. doi: 10.1038/s41419-020-02979-9.

Abstract

Lung cancer is the leading cause of cancer-associated mortality worldwide. DNA damage-regulated autophagy modulator 1 (DRAM1) plays an important roles in autophagy and tumor progression. However, the mechanisms by which DRAM1 inhibits tumor growth are not fully understood. Here, we report that DRAM1 was decreased in nonsmall-cell lung carcinoma (NSCLC) and was associated with poor prognosis. We confirmed that DRAM1 inhibited the growth, migration, and invasion of NSCLC cells in vitro. Furthermore, overexpression of DRAM1 suppressed xenografted NSCLC tumors in vivo. DRAM1 increased EGFR endocytosis and lysosomal degradation, downregulating EGFR signaling pathway. On one side, DRAM1 interacted with EPS15 to promote EGFR endocytosis, as evidence by the results of proximity labeling followed by proteomics; on the other, DRAM1 recruited V-ATP6V1 subunit to lysosomes, thereby increasing the assemble of the V-ATPase complex, resulting in decreased lysosomal pH and increased activation of lysosomal proteases. These two actions of DRAM1 results in acceleration of EGFR degradation. In summary, these in vitro and in vivo studies uncover a novel mechanism through which DRAM1 suppresses oncogenic properties of NSCLC by regulating EGFR trafficking and degradation and highlights the potential value of DRAM1 as a prognostic biomarker in lung cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Animals
  • Biomarkers, Tumor / metabolism
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Cell Line, Tumor
  • Cell Movement
  • Cell Proliferation
  • Computational Biology
  • DNA Damage
  • Endocytosis
  • ErbB Receptors / metabolism
  • HEK293 Cells
  • Humans
  • Hydrogen-Ion Concentration
  • Lung Neoplasms / metabolism*
  • Lysosomes / metabolism*
  • Male
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Middle Aged
  • Neoplasm Invasiveness
  • Neoplasm Transplantation
  • Prognosis

Substances

  • Biomarkers, Tumor
  • DRAM-1 protein, mouse
  • DRAM1 protein, human
  • Membrane Proteins
  • EGFR protein, human
  • ErbB Receptors