Sustained NF-κB activation allows mutant alveolar stem cells to co-opt a regeneration program for tumor initiation

Area of Science:

• Stem cell biology
• Cancer research
• Lung development

Background:

• Disruptions in stem cell regulatory signals can lead to tumorigenesis.
• Understanding the destabilization of these programs is crucial for cancer prevention and treatment.

Purpose of the Study:

• To investigate the mechanisms by which stem cell fate programs become destabilized, leading to lung tumorigenesis.
• To identify key molecular players and cellular dynamics involved in the transition from normal stem cell function to cancerous growth.

Main Methods:

• In vivo fate-mapping of thousands of murine wild-type and KrasG12D-mutant alveolar type II (AT2) stem cells.
• Clonal analyses combined with single-cell transcriptomics.
• Investigation of signaling pathways including Il1r1 and nuclear factor κB (NF-κB).

Main Results:

• Identified two independent AT2 stem cell subpopulations with distinct tumorigenic capacities.
• Revealed parallels between lung regeneration and tumorigenesis, implicating Il1r1 in AT2 reprogramming.
• Demonstrated that tumor evolution involves lineage infidelity and reversible mutant state transitions.
• Showed sustained NF-κB activation distinguishes tumorigenesis from regeneration by promoting tumor growth over differentiation.

Conclusions:

• Lung tumorigenesis arises from destabilized stem cell fate programs, involving distinct AT2 subpopulations.
• Il1r1 acts as a common activator for AT2 reprogramming in both regeneration and cancer.
• Sustained NF-κB signaling is a critical differentiator, enabling tumor growth by overriding normal differentiation processes.