Oncogenic KRAS Induces NIX-Mediated Mitophagy to Promote Pancreatic Cancer

Area of Science:

• Oncology
• Cell Biology
• Molecular Biology

Background:

• Activating KRAS mutations are hallmarks of pancreatic ductal adenocarcinoma (PDAC).
• Targeting KRAS directly has proven challenging, necessitating research into KRAS-dependent pathways for novel therapeutic strategies.
• Understanding these pathways is crucial for identifying vulnerabilities in PDAC.

Purpose of the Study:

• To investigate the role of KRAS-induced pathways in PDAC progression.
• To identify novel therapeutic targets by understanding KRAS-driven cellular mechanisms.
• To explore the function of BNIP3L/NIX in the context of oncogenic KRAS signaling.

Main Methods:

• Analysis of KRAS-induced gene expression and mitophagy.
• CRISPR-mediated knockout of Nix in cell lines and murine models (KPC).
• Assessment of mitochondrial content, glucose flux, NADPH production, and tumor progression.

Main Results:

• Oncogenic KRAS upregulates BNIP3L/NIX, initiating selective mitophagy.
• Nix deletion impairs mitochondrial function, increases NADPH demand, and reduces proliferation under glucose limitation.
• Nix deletion in KPC mice significantly delays PDAC progression and improves survival.
• In vivo Nix ablation leads to transient mitochondrial accumulation followed by normalization via enhanced clearance.

Conclusions:

• The KRAS-NIX mitophagy pathway is a novel driver of glycolysis, redox homeostasis, and PDAC progression.
• NIX-mediated mitophagy suppresses functional mitochondria, promoting proliferation and redox balance.
• This pathway represents a new oncogenic KRAS effector mechanism and a potential therapeutic dependency in pancreatic cancer.