Nras(G12D/+) promotes leukemogenesis by aberrantly regulating hematopoietic stem cell functions.

Area of Science:

• Hematology
• Cancer Biology
• Molecular Oncology

Background:

• Oncogenic NRAS mutations are common in human myeloid leukemias.
• NRAS signaling's role in leukemogenesis is not fully understood.
• Previous studies showed Nras expression in mice causes myeloproliferative neoplasms (MPNs).

Purpose of the Study:

• To investigate the mechanisms by which oncogenic NRAS signaling promotes leukemogenesis.
• To identify the specific cell types and signaling pathways involved in NRAS-driven myeloid malignancies.

Main Methods:

• Utilized mouse models with oncogenic Nras expression in hematopoietic cells.
• Analyzed hematopoietic stem cell (HSC) function, proliferation, and self-renewal.
• Investigated the role of the MEK/ERK signaling pathway using pharmacologic and genetic inhibition.

Main Results:

• Hematopoietic stem cells (HSCs) expressing oncogenic Nras (Nras(G12D/+)) initiate MPNs.
• Nras(G12D/+) HSCs exhibit moderate hyperproliferation and increased self-renewal.
• Aberrant NRAS signaling leads to ERK1/2 hyperactivation in HSCs.
• Inhibition of MEK/ERK signaling attenuated Nras(G12D/+) HSC cycling and progenitor expansion.

Conclusions:

• Hematopoietic stem cells (HSCs) expressing oncogenic NRAS are critical for initiating myeloproliferative neoplasms (MPNs).
• Hyperactivation of the ERK1/2 pathway in HSCs is a key mechanism in NRAS-driven leukemogenesis.
• Targeting the MEK/ERK pathway offers a potential therapeutic strategy for NRAS-mutant myeloid leukemias.