In a groundbreaking study poised to reshape our understanding of pancreatic cancer therapeutics, researchers have unveiled a critical metabolic signaling axis that governs drug resistance mechanisms in KRAS-mutant cancers. The investigation, published in Nature, details how cytosolic acetyl-coenzyme A (AcCoA) modulates mitophagy through NLRX1-dependent pathways, providing new insight into overcoming resistance to KRAS inhibitors (KRASi)—a class of drugs with immense promise given the prevalence of KRAS mutations in human malignancies.
KRAS mutations are notorious drivers in approximately 30% of all human cancers, with an overwhelming 90% incidence in pancreatic ductal adenocarcinoma (PDAC), a malignancy characterized by dismal prognosis and limited treatment options. KRAS inhibitors have been hailed as potential game-changers, yet their clinical efficacy is frequently undermined by acquired drug resistance. This research addresses a critical gap: the role of metabolic rewiring and mitochondrial quality control, particularly mitophagy, in mediating resistance to KRAS-targeted therapies.
The study centers on the observation that KRAS inhibitors, specifically MRTX1133 targeting the KRAS(G12D) mutant and the pan-RAS inhibitor RMC-6236, lead to a significant reduction in ATP citrate lyase (ACLY) expression and consequently decrease cytosolic AcCoA levels in both murine KPC cells and human PDAC AsPC-1 cells harboring KRAS(G12D) mutations. This metabolic suppression initiates a cascade culminating in elevated mitophagy, a selective autophagic process for mitochondrial turnover. Importantly, the induction of mitophagy by KRAS inhibition was effectively antagonized by exogenous acetate supplementation, underscoring the centrality of the ACLY-AcCoA axis in controlling this process.
Delving deeper, the researchers demonstrated that mitophagy triggered by KRASi is strikingly dependent on NLRX1, a mitochondrial NOD-like receptor previously implicated in innate immune signaling and mitochondrial homeostasis. NLRX1-deficient cells exhibited a near-complete abrogation of KRASi-induced mitophagy, illuminating its indispensable role as a mediator of mitochondrial quality control in this context. The absence of NLRX1 not only hindered mitophagy but also resulted in pronounced accumulation of reactive oxygen species (ROS) and heightened cellular oxidative stress, as evidenced by increased NADP⁺/NADPH ratios.
The functional consequences of these molecular events were profound. NLRX1 deficiency sensitized cancer cells to KRAS inhibition, augmenting cytotoxicity in both murine and human KRAS-mutant PDAC and lung cancer models. This finding was further bolstered by experiments involving the antioxidant N-acetyl-L-cysteine (NAC), which rescued the viability of NLRX1-deficient cells exposed to KRASi by mitigating oxidative stress. It became evident that the mitophagy pathway represents a cellular defensive maneuver that mitigates ROS-induced damage to sustain tumor cell survival during KRAS-targeted therapy.
Complementing the in vitro analyses, in vivo studies employing a subcutaneous KPC tumor model in NSG mice cemented the therapeutic relevance of the ACLY–AcCoA–NLRX1 axis. Mice receiving the KRAS inhibitor MRTX1133 exhibited notable tumor regression, an effect amplified in the absence of NLRX1. Moreover, immunoblot and histological analyses revealed that while Acly suppression occurred uniformly across conditions, mitochondrial protein levels—indicative of mitophagy—were preserved in NLRX1-deficient tumors, affirming the disrupted mitophagic response. Consistently, ROS levels were reduced in control tumors following KRASi but escalated in NLRX1-lacking specimens, reinforcing the interplay between mitophagy, redox balance, and therapy resistance.
These revelations shift the paradigm by identifying mitophagy not merely as a housekeeping process but as a vital resistance mechanism exploited by cancer cells under pharmacologic assault. The study’s insights suggest that targeting the metabolic regulation of mitophagy—specifically through the ACLY-AcCoA-NLRX1 signaling axis—may enhance the efficacy of KRAS inhibitors and suppress tumor adaptation.
Intriguingly, this research also reports synergistic antitumor effects when combining KRAS inhibitors with mitophagy inhibitors like Mdivi-1, which exacerbates mitochondrial dysfunction and oxidative stress in cancer cells. This dual targeting strategy presents a compelling therapeutic avenue, potentially circumventing the resilience conferred by mitophagy-mediated mitochondrial clearance.
From a mechanistic viewpoint, the intimate connection between decreased ACLY activity and mitophagy induction underscores the broader concept that metabolic state functions as a signaling nexus. Cytosolic AcCoA emerges as more than a metabolic intermediate; it acts as a signaling metabolite communicating cellular energy and nutrient status to the mitophagy machinery. This axis elegantly illustrates how metabolic rewiring can intersect with organelle quality control to govern cell fate decisions during oncogenic stress.
Beyond immediate therapeutic implications, these findings raise significant questions about mitophagy’s role across diverse KRAS-mutant tumor types and contexts of therapy resistance. As chronic KRAS inhibition becomes more prevalent in clinical oncology, understanding how tumor cells engage mitochondrial quality control pathways could guide the design of combinatorial regimens that preempt or reverse resistance.
Moreover, this study highlights the vital importance of ROS homeostasis in malignancies driven by KRAS mutations. The intricate balance between mitochondrial removal and redox signaling revealed here may represent a universal vulnerability exploitable across cancers characterized by oxidative stress adaptations.
In conclusion, the elucidation of the ACLY–AcCoA–NLRX1 axis as a regulator of mitophagy in KRAS inhibitor-mediated drug resistance broadens the framework of cancer metabolism and organelle dynamics in oncogenesis. It opens exciting pathways for innovative treatments that disrupt tumor adaptive mechanisms, potentially transforming outcomes for patients afflicted with some of the deadliest KRAS-driven cancers.
Subject of Research:
KRAS-mutant cancer metabolism, mitophagy, and drug resistance mechanisms
Article Title:
Cytosolic acetyl-coenzyme A is a signalling metabolite to control mitophagy
Article References:
Zhang, Y., Shen, X., Shen, Y. et al. Cytosolic acetyl-coenzyme A is a signalling metabolite to control mitophagy. Nature (2025). https://doi.org/10.1038/s41586-025-09745-x
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