ALK inhibition activates LC3B-independent, protective autophagy in EML4-ALK positive lung cancer cells

Sci Rep. 2021 Apr 27;11(1):9011. doi: 10.1038/s41598-021-87966-6.

Abstract

ALK inhibitors effectively target EML4-ALK positive non-small cell lung cancer, but their effects are hampered by treatment resistance. In the present study, we asked whether ALK inhibition affects autophagy, and whether this may influence treatment response. Whereas the impact of targeted therapies on autophagic activity previously have been assessed by surrogate marker proteins such as LC3B, we here thoroughly examined effects on functional autophagic activity, i.e. on the sequestration and degradation of autophagic cargo, in addition to autophagic markers. Interestingly, the ALK inhibitor Ceritinib decreased mTOR activity and increased GFP-WIPI1 dot formation in H3122 and H2228 EML4-ALK+ lung cancer cells, suggesting autophagy activation. Moreover, an mCherry-EGFP-LC3B based assay indicated elevated LC3B carrier flux upon ALK inhibition. In accordance, autophagic cargo sequestration and long-lived protein degradation significantly increased upon ALK inhibition. Intriguingly, autophagic cargo flux was dependent on VPS34 and ULK1, but not LC3B. Co-treating H3122 cells with Ceritinib and a VPS34 inhibitor or Bafilomycin A1 resulted in reduced cell numbers. Moreover, VPS34 inhibition reduced clonogenic recovery of Ceritinib-treated cells. In summary, our results indicate that ALK inhibition triggers LC3B-independent macroautophagic flux in EML4-ALK+ cells to support cancer cell survival and clonogenic growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaplastic Lymphoma Kinase / antagonists & inhibitors*
  • Antineoplastic Agents / pharmacology*
  • Autophagy / drug effects*
  • Autophagy-Related Protein-1 Homolog / metabolism
  • Carcinoma, Non-Small-Cell Lung / enzymology
  • Carcinoma, Non-Small-Cell Lung / immunology*
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Class III Phosphatidylinositol 3-Kinases / antagonists & inhibitors
  • Class III Phosphatidylinositol 3-Kinases / metabolism
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Lung Neoplasms / enzymology
  • Lung Neoplasms / immunology*
  • Lung Neoplasms / metabolism
  • Microtubule-Associated Proteins / metabolism
  • Oncogene Proteins, Fusion / metabolism*
  • Pyrimidines / pharmacology*
  • Sulfones / pharmacology*

Substances

  • Antineoplastic Agents
  • EML4-ALK fusion protein, human
  • Intracellular Signaling Peptides and Proteins
  • MAP1LC3B protein, human
  • Microtubule-Associated Proteins
  • Oncogene Proteins, Fusion
  • Pyrimidines
  • Sulfones
  • Class III Phosphatidylinositol 3-Kinases
  • ALK protein, human
  • Anaplastic Lymphoma Kinase
  • Autophagy-Related Protein-1 Homolog
  • ULK1 protein, human
  • ceritinib