Imaging dynamic mTORC1 pathway activity in vivo reveals marked shifts that support time-specific inhibitor therapy in AML

Nat Commun. 2021 Jan 11;12(1):245. doi: 10.1038/s41467-020-20491-8.

Abstract

Acute myeloid leukemia (AML) is a high remission, high relapse fatal blood cancer. Although mTORC1 is a master regulator of cell proliferation and survival, its inhibitors have not performed well as AML treatments. To uncover the dynamics of mTORC1 activity in vivo, fluorescent probes are developed to track single cell proliferation, apoptosis and mTORC1 activity of AML cells in the bone marrow of live animals and to quantify these activities in the context of microanatomical localization and intra-tumoral heterogeneity. When chemotherapy drugs commonly used clinically are given to mice with AML, apoptosis is rapid, diffuse and not preferentially restricted to anatomic sites. Dynamic measurement of mTORC1 activity indicated a decline in mTORC1 activity with AML progression. However, at the time of maximal chemotherapy response, mTORC1 signaling is high and positively correlated with a leukemia stemness transcriptional profile. Cell barcoding reveals the induction of mTORC1 activity rather than selection of mTORC1 high cells and timed inhibition of mTORC1 improved the killing of AML cells. These data define the real-time dynamics of AML and the mTORC1 pathway in association with AML growth, response to and relapse after chemotherapy. They provide guidance for timed intervention with pathway-specific inhibitors.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Cell Line, Tumor
  • Disease Progression
  • Down-Regulation
  • Drug Resistance, Neoplasm / genetics
  • Gene Expression Regulation, Leukemic
  • Leukemia, Myeloid, Acute / drug therapy*
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / pathology
  • Mechanistic Target of Rapamycin Complex 1 / antagonists & inhibitors*
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Mice
  • Models, Biological
  • NIH 3T3 Cells
  • RNA-Binding Proteins / metabolism
  • Signal Transduction
  • Transcriptome / genetics
  • Treatment Outcome

Substances

  • Apoptosis Regulatory Proteins
  • Pdcd4 protein, mouse
  • RNA-Binding Proteins
  • Mechanistic Target of Rapamycin Complex 1