Somatic mtDNA mutation burden shapes metabolic plasticity in leukemogenesis.

Area of Science:

• Mitochondrial genetics
• Cancer biology
• Hematopoiesis

Background:

• The role of somatic mitochondrial DNA (mtDNA) mutations in leukemogenesis is not well understood.
• Mitochondrial dysfunction is increasingly recognized as a factor in cancer development.

Purpose of the Study:

• To investigate the impact of somatic mtDNA mutations on the leukemogenic potential of hematopoietic progenitor cells (HPCs).
• To assess the interplay between mtDNA mutations and NMyc oncogene in leukemia.

Main Methods:

• Utilized mtDNA mutator mice (Polg D257A) with varying degrees of mtDNA mutation burden (heterozygous and homozygous).
• Transplanted hematopoietic progenitor cells (HPCs) into recipient mice, with and without NMyc overexpression.
• Analyzed leukemogenesis incidence, mitochondrial function, and cellular metabolism (glucose utilization, pyruvate dehydrogenase activity).

Main Results:

• Heterozygous Polg HPCs showed increased spontaneous leukemogenesis; homozygous Polg HPCs exhibited reduced NMyc-driven leukemia.
• Both heterozygous and homozygous mtDNA mutations impaired baseline mitochondrial function, but only heterozygous HPCs supported NMyc-driven metabolic demands.
• Homozygous HPCs displayed altered glucose metabolism and pyruvate dehydrogenase inhibition, exacerbated by NMyc, which was partially rescued by inhibiting pyruvate dehydrogenase kinase.

Conclusions:

• Somatic mtDNA mutations significantly influence leukemogenesis, with varying effects depending on mutation burden and oncogene cooperation.
• Metabolic plasticity, particularly glucose utilization and pyruvate dehydrogenase activity, is a critical factor modulated by mtDNA mutation load in NMyc-driven leukemia.
• These findings highlight a complex relationship between mitochondrial integrity, metabolic adaptation, and cancer development.