At the heart of this discovery is OXCT1, a key enzyme traditionally recognized for its rate-limiting role in ketone body catabolism. Interestingly, researchers found that elevated OXCT1 expression in tumor biopsies correlated with poorer outcomes following ICB therapy in HCC patients. Conversely, the metabolite β-hydroxybutyrate (BHB), which serves as the substrate for OXCT1, displayed an inverse relationship with therapy success, suggesting that the tumor’s ability to utilize ketone bodies via OXCT1 significantly impacts immune-mediated tumor eradication. This paradoxical finding challenges the conventional understanding of tumor metabolism and beckons a deeper dive into the molecular crosstalk between metabolism and immune regulation.

Delving into the cellular dynamics, the team discovered that glucose deprivation—a common metabolic stress within the tumor microenvironment—triggers a critical post-translational modification of OXCT1. Specifically, AMP-activated protein kinase (AMPK), a master regulator of energy metabolism, phosphorylates OXCT1 at serine 113. This modification serves as a molecular switch that exposes an otherwise obscured nuclear localization sequence within OXCT1, prompting its translocation from the cytoplasm into the cell nucleus. This translocation event marks a paradigm shift in the functional repertoire of OXCT1, extending its metabolic role beyond the mitochondria to chromatin regulation.

Once inside the nucleus, OXCT1 adopts a non-canonical role: it physically interacts with the transcription factor IRF1, a pivotal regulator of immune gene expression. This complex acts locally to metabolize BHB directly at the chromatin level, thereby reducing the availability of BHB for histone β-hydroxybutyrylation (Kbhb) on histone H3K9 residues. Histone modifications like H3K9 β-hydroxybutyrylation are epigenetic marks known to generally promote gene transcription. By consuming BHB near critical genomic loci, nuclear OXCT1 effectively suppresses Kbhb at the promoters of genes encoding major histocompatibility complex class I (MHC-I) molecules and chemokines, both essential for robust anti-tumor immune responses.

The repression of MHC-I and chemokine gene expression through this metabolic-epigenetic axis creates an immunosuppressive microenvironment, dampening the capacity of cytotoxic T cells to recognize and eliminate tumor cells. The significance of this finding lies in elucidating a mechanistic link whereby tumor metabolic status dynamically sculpts immune evasion strategies, illuminating how metabolic reprogramming directly alters the epigenetic landscape to favor immune escape. This insight aligns with emerging concepts that cancer metabolism and immune modulation are intricately intertwined rather than separate therapeutic realms.

Perhaps most exciting is the therapeutic potential unveiled by these findings. The researchers demonstrated that pharmacological or genetic disruption of the AMPK−OXCT1−IRF1 pathway sensitizes HCC tumor cells to immune checkpoint inhibitors, especially when combined with a ketogenic diet—a high-fat, low-carbohydrate nutritional approach that elevates circulating ketone levels like BHB. This combinatorial strategy synergizes to enhance tumor immunogenicity and overcome resistance, opening a novel avenue for personalized metabolic-immunotherapy strategies in HCC and potentially other cancers reliant on ketone metabolism.

This study not only advances scientific understanding of ketone body biology in cancer but also underscores the critical need to consider metabolic states as mutable factors within the tumor microenvironment that dictate immune surveillance and therapy outcomes. The nuclear translocation of OXCT1 unveils a previously unrecognized epigenetic regulatory mechanism controlled by metabolism, which could be exploited for biomarker development, patient stratification, and crafting next-generation immunometabolic therapies.

By bridging cellular metabolism, epigenetic modification, and immune regulation, this research embodies the growing appreciation that cancer is a systemic and adaptive disease. It challenges the one-dimensional perspective of metabolic enzymes as mere metabolic catalysts, repositioning them as multifaceted agents directly influencing gene expression programs pivotal for the tumor-immune interplay. This sophisticated level of regulation adds complexity to our understanding but also equips researchers and clinicians with new targets to manipulate the cancer immunity cycle more effectively.

Moreover, the work suggests that metabolic interventions like ketogenic diets may have untapped roles in modulating tumor immunity by influencing ketone availability and utilization. While ketogenic diets have been explored primarily for their systemic metabolic effects, this mechanistic insight justifies further clinical exploration to harness dietary modulation as an adjunct in immunotherapy regimens.

The methodological rigor behind these discoveries combines multiomics analyses—integrating transcriptomics, epigenomics, metabolomics, and proteomics—on patient tumor biopsies treated with immune checkpoint blockade. This comprehensive approach captures the dynamic metabolic-epigenetic alterations within clinically relevant contexts, strengthening the translational relevance of the findings. Such integrative methodologies represent the future of cancer research by providing holistic views of tumor biology necessary for innovative therapy designs.

This research reframes the landscape of cancer immunotherapy by implicating metabolic enzymes as gatekeepers of epigenetic states that determine immune gene accessibility. Therapeutically targeting these non-canonical functions could circumvent intrinsic and acquired immunotherapy resistance mechanisms that have long hindered patient outcomes in hepatocellular carcinoma and potentially other solid tumors.

Continued exploration into the diverse roles of metabolic enzymes in the nucleus promises to unravel additional layers of complexity linking metabolism and gene regulation. Such discoveries could yield a new class of metabolic-epigenetic checkpoints—offering novel intervention points to boost anti-tumor immunity synergistically with established immunotherapies.

In summary, this study compellingly illuminates how nuclear translocation of OXCT1 under metabolic stress conditions subverts the epigenetic regulation of immune genes to promote immune evasion in hepatocellular carcinoma. By unveiling this previously unknown mechanistic nexus between ketone metabolism, histone modification, and immune transcriptional control, the research opens promising new horizons for enhancing immunotherapy efficacy through precise metabolic reprogramming. The findings underscore the power of integrating metabolism-centric perspectives into immuno-oncology and inspire future efforts to develop targeted interventions that restore tumor immune visibility and responsiveness.

Understanding such complex immunometabolic interactions is pivotal for overcoming some of the most pressing challenges in modern oncology. As cancer therapies evolve, leveraging knowledge of the intimate cross talk between tumor metabolism and immune regulation will be essential to designing holistic treatment paradigms that achieve durable responses across diverse patient populations.

Subject of Research: The interplay between ketone body metabolism, epigenetic regulation, and immune gene transcription influencing immunotherapy responsiveness in hepatocellular carcinoma.

Article Title: Nuclear OXCT1 attenuates histone β-hydroxybutyrylation-mediated MHC-I transcription.

Article References:
Hu, Z., Lv, W., Wen, T. et al. Nuclear OXCT1 attenuates histone β-hydroxybutyrylation-mediated MHC-I transcription. Nat Chem Biol (2026). https://doi.org/10.1038/s41589-026-02229-7

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41589-026-02229-7

For over thirty years, CCDC6-RET has been recognized as a potent driver of malignancies, but the intricate molecular underpinnings governing its activation remained elusive. Unlike canonical kinases that rely exclusively on ATP (adenosine triphosphate) hydrolysis to propagate phosphorylation cascades, CCDC6-RET demonstrates a dual capacity to harness both ATP and its metabolic byproduct, ADP (adenosine diphosphate), as phosphate donors. This duality suggests a remarkable fuel efficiency, enabling the kinase to sustain its oncogenic signaling even under metabolically compromised conditions typical of tumor microenvironments.

At the molecular level, protein kinases generally proceed through a sequential activation involving the transfer of phosphate groups from ATP molecules to specific amino acid residues, predominantly serine, threonine, or tyrosine. This process modulates substrate activity and propagates intracellular signals essential for diverse cellular functions. However, CCDC6-RET diverges sharply by simultaneously phosphorylating multiple domains, a phenomenon that accelerates its activation kinetics compared to native RET kinase. Such accelerated phosphorylation amplifies the downstream signaling outputs, intensifying the oncogenic drive and contributing to rapid tumor cell proliferation.

The fusion protein arises from a gene rearrangement event whereby the RET gene aberrantly fuses with the CCDC6 gene, producing a chimeric oncoprotein with altered structural properties. This fusion event is emblematic of a broader class of oncogenic mutations characterized by gene fusions that bestow neomorphic properties upon the resultant proteins. These fusion proteins often exhibit heightened enzymatic activity, altered substrate specificity, or novel subcellular localization, all contributing to malignant transformation. The CCDC6-RET chimera exemplifies these trends but stands out due to its unprecedented energy utilization flexibility.

Researchers employed an integrative approach combining crystallography, cryo-electron microscopy, and artificial intelligence-driven protein modeling to resolve the three-dimensional structures of both the inactive and active forms of CCDC6-RET. Their structural insights reveal the conformational rearrangements facilitating its unique dual ATP/ADP-dependent kinase activity. This comprehensive structural characterization lays a foundation for rational drug design aimed at selectively inhibiting this fusion protein, which traditional RET inhibitors may inadequately target due to their inability to account for the ADP-utilization mechanism.

The recognition that ADP functions not merely as a metabolic waste product but also as an active cofactor in kinase activation opens novel conceptual frameworks in cellular bioenergetics and signal transduction. It suggests that tumor cells might exploit metabolic intermediates to sustain oncogenic signaling pathways, thereby circumventing nutrient deprivation or pharmacological inhibition. In this context, CCDC6-RET can be viewed as a molecular exemplar of metabolic adaptability, harnessing energy substrates beyond the canonical ATP pool to maintain its function.

Clinically, this discovery prompts a reassessment of existing therapies targeting RET fusions. Current inhibitors predominantly focus on blocking ATP-binding sites; however, the ability of CCDC6-RET to functionalize ADP suggests that these approaches might only partially suppress its kinase activity. Therefore, the development of novel modulators capable of disrupting both ATP- and ADP-mediated activation states could yield more effective therapeutic responses, reducing resistance and improving patient outcomes.

The study also provokes broader inquiries into the prevalence of similar dual nucleotide-utilizing kinases within the human kinome and their roles in cancer metabolism. If such mechanisms are more widespread, they could signify an underappreciated avenue of metabolic flexibility exploited by cancer cells, warranting comprehensive screening and functional assays across various oncogenic kinases.

Moreover, these findings underscore the interplay between oncogenic signaling and metabolic regulation within the tumor milieu. Tumor cells are known to reprogram their metabolism to sustain rapid growth, often under hypoxic or nutrient-scarce environments. The dual reliance on ATP and ADP by CCDC6-RET could represent a survival mechanism allowing continuous signaling despite fluctuating intracellular energy states, a feature that might be critical in tumor progression and resistance to therapy.

Looking ahead, the CNIO research team envisions leveraging the detailed structural and mechanistic insights obtained to design next-generation kinase inhibitors with enhanced specificity and potency against RET fusion proteins. Such drugs could potentially exhibit novel modes of action, including allosteric inhibition or disruption of ADP binding, thereby overcoming limitations of current ATP-competitive therapies.

In summary, the elucidation of CCDC6-RET as a dual ATP- and ADP-dependent kinase redefines our understanding of kinase activation, particularly in the context of oncogenic fusion proteins. This paradigm-shifting discovery not only deepens the molecular knowledge of cancer biology but also catalyzes innovative therapeutic development aimed at some of the most refractory malignancies driven by RET fusions.

Subject of Research: Cells
Article Title: The oncogenic CCDC6-RET fusion protein is a dual ATP- and ADP-dependent kinase
News Publication Date: 6-Mar-2026
Web References: https://www.nature.com/articles/s41467-026-69833-y#data-availability
References: DOI: 10.1038/s41467-026-69833-y
Image Credits: Christian Esposito / Madmoviex / CNIO
Keywords: Oncogenes, Cancer genome sequencing, Proteins, Mutant proteins, Kinase activity, Kinase signaling, Protein activation, Receptor activation, Personalized medicine, Target proteins

Cancer metabolism has long captured scientific curiosity, predominantly due to the stark metabolic alterations cancer cells undergo to support unchecked proliferation. Traditionally, the Warburg effect—where cancer cells increases their reliance on glycolysis even in oxygen-rich conditions—has dominated our conceptual framework. Yet, emerging evidence suggested a more complex scenario involving metabolic plasticity where OXPHOS remains active alongside glycolysis. This latest research now deciphers this intricate balance with unprecedented clarity.

The study, titled “Absolute dynamic and relative static: the relationship of glycolysis and OXPHOS in cancer development,” led by Bao, Hou, Guo, and their colleagues, methodically characterizes how these metabolic pathways do not simply toggle between on and off but instead interact in a dynamic absolute manner and relative static fashion depending on tumor progression stages and microenvironmental cues.

Using cutting-edge metabolomics and live-cell imaging techniques, the investigators tracked metabolic fluxes with exquisite temporal resolution in cancer cell lines and primary tumor samples. They demonstrated that glycolysis operates as an absolute dynamic system, exhibiting fluctuations in response to both internal genetic changes and external stimuli such as hypoxia and nutrient availability. In contrast, OXPHOS maintains a relatively static state, serving as a metabolic backbone that supports bioenergetic homeostasis but subtly adapts in a complementary manner.

At the heart of this discovery is the establishment that instead of mutual exclusivity, glycolysis and OXPHOS engage in an adaptive interplay, allowing cancer cells to finely tune energy production and biosynthetic processes. This adaptive mechanism is critical during different phases of cancer progression, from early proliferation to later metastatic spread, underscoring the metabolic flexibility conferring survival advantages under fluctuating environmental stressors.

Moreover, the researchers identified specific signaling nodes and regulatory proteins that mediate this dynamic-static relationship. Key transcription factors and metabolic enzymes act as molecular switches or rheostats, modulating pathway fluxes while preserving cellular viability and growth capacity. These findings illuminate how cancer cells harness metabolic regulation to optimize ATP generation while balancing reactive oxygen species (ROS) production and redox status.

The implications for therapeutic development are profound. Since both glycolytic and OXPHOS pathways contribute to tumor fitness in a context-dependent manner, targeting only one pathway might be insufficient or even counterproductive. Future cancer treatments may require a dual-pathway modulation strategy, designed to disrupt the delicate flux balance and sensitize cancer cells to metabolic stressors without harming normal tissue metabolism.

Interestingly, the study also highlights metabolic heterogeneity within tumor populations. Not all cells within the same tumor employ identical metabolic strategies; some rely more heavily on glycolysis, others maintain OXPHOS dominance, and yet others fluctuate between these states dynamically. This intratumoral metabolic diversity poses further challenges to therapeutic targeting but also opens avenues for precision medicine based on metabolic phenotyping.

The continued development of metabolic inhibitors, combined with real-time monitoring of cellular metabolism, could allow clinicians to dynamically adjust treatments in response to evolving tumor metabolic profiles. This precision approach holds promise for overcoming resistance mechanisms that arise from metabolic plasticity, a key hurdle in existing cancer therapies.

Beyond cancer, the fundamental principles derived from this study may extend to other pathological states characterized by metabolic dysregulation, including neurodegenerative diseases and immune dysfunction. Understanding the balance and interplay between glycolysis and OXPHOS could provide biomarkers or intervention points for diseases where cellular energetics are compromised.

Technologically, the study leverages innovations such as fluorescence lifetime imaging microscopy (FLIM) to spy on NADH levels and infer metabolic states with unparalleled spatiotemporal accuracy. These tools not only elucidate cellular metabolism but also pave the way for metabolic imaging diagnostics—potentially transforming early cancer detection and monitoring.

The breadth of this research underscores an essential paradigm shift in cancer biology—from viewing metabolic pathways as discrete and static modules to appreciating their dynamic and context-sensitive orchestration. This shift not only enriches our biochemical understanding but also catalyzes a new era in translational oncology focused on metabolic adaptability as a diagnostic and therapeutic target.

In conclusion, the elegant dissection of glycolysis and OXPHOS dynamics provided in this study marks a seminal advance. It propels the field beyond simplified dichotomies, offering a comprehensive framework that integrates metabolic flexibility into the narrative of cancer progression. As such, it ignites pathways for developing more effective, metabolism-centered therapeutic regimens that can outmaneuver cancer’s adaptive prowess.

Subject of Research: The dynamic and regulatory relationship between glycolysis and oxidative phosphorylation (OXPHOS) in cancer development and metabolic reprogramming.

Article Title: Absolute dynamic and relative static: the relationship of glycolysis and OXPHOS in cancer development.

Article References:
Bao, X., Hou, B., Guo, Z. et al. Absolute dynamic and relative static: the relationship of glycolysis and OXPHOS in cancer development. Cell Death Discov. (2026). https://doi.org/10.1038/s41420-026-02992-5

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41420-026-02992-5