Acetoacetate suppresses colon cancer via an MR1-MAIT axis

Clay, S. L.; El Tekle, G.; Rashan, E. H.; Fonseca-Pereira, D.; Shin, Y.-H.; Andreeva, N.; Nakatsu, G.; Lobo, A. F.; Chen, S. P.; Bae, S.; Michaud, M.; Glickman, J. N.; Clardy, J.; Vander Heiden, M.; Garrett, W.

doi:10.1101/2025.10.29.685375

bioRxiv · 10.1101/2025.10.29.685375

Acetoacetate suppresses colon cancer via an MR1-MAIT axis

Clay, S. L.·El Tekle, G.·Rashan, E. H.·Fonseca-Pereira, D.·Shin, Y.-H.·Andreeva, N.·Nakatsu, G.·Lobo, A. F.·Chen, S. P.·Bae, S.·Michaud, M.·Glickman, J. N.·Clardy, J.·Vander Heiden, M.·Garrett, W.

View original source ↗Export metadata ↓

Abstract

Colorectal cancer (CRC) is a leading cause of cancer mortality and additional preventative, and therapeutic strategies are urgently needed. Ketogenic diets have mixed effects on tumorigenesis and compliance is challenging. Exogenous ketones, {beta}-hydroxybutyrate ({beta}HB) or acetoacetate (AcAc), offer an alternative approach. While {beta}HB has been investigated, the anti-cancer effects of AcAc are poorly defined. Here, we show that orally administering ethyl AcAc (EAA) suppresses tumor growth in several pre-clinical CRC models. Single-cell RNA sequencing, flow cytometry, and genetic and antibody-mediated depletion studies reveal that EAA selectively expands and activates cytotoxic mucosal-associated invariant T (MAIT) cells in an MHC class I-related protein 1 (MR1)-dependent manner. EAA increases MR1 expression by tumor monocytes, which is recapitulated in human cell cultures, where AcAc and 5-amino-6-D-ribitylaminouracil (5-A-RU) induce MAIT cell expansion and tumor killing. Mechanistically, AcAc converts to methylglyoxal, combining with microbially-derived 5-A-RU to generate 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU), a potent MR1 ligand. These findings identify an AcAc-MR1-MAIT cell axis as a potential immunotherapy approach for CRC therapy.

Explore related subjects

immunology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Clay, S. L., El Tekle, G., Rashan, E. H., Fonseca-Pereira, D., Shin, Y.-H., Andreeva, N., Nakatsu, G., Lobo, A. F., Chen, S. P., Bae, S., Michaud, M., Glickman, J. N., Clardy, J., Vander Heiden, M., Garrett, W.. 2025-10-30. Acetoacetate suppresses colon cancer via an MR1-MAIT axis. https://doi.org/10.1101/2025.10.29.685375

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Ksp37 is a rapidly mobilized NK cell secretory protein that engages FGF2

A key feature of natural killer (NK) cells is their preloaded arsenal of effector molecules, allowing them to rapidly respond upon activation. In this study, we characterized a previously unexplored secretory protein, termed killer-specific secretory protein of 37 kDa (Ksp37), which is highly abundant in differentiated CD56dim NK cells. Ksp37 is rapidly secreted in a dose-dependent and JAK-1 dependent manner upon low levels of cytokine stimulation, making it a sensitive readout for NK cell activation. Following secretion, intracellular levels were rapidly replenished, preserving responsiveness to subsequent cytokine stimulation. We found that Ksp37 is stored in polarized intracellular compartments distinct from those containing canonical cytotoxic effector molecules, including granzyme B and perforin, which require stronger stimulation for release. Lastly, we identified Ksp37 as a novel binding partner of fibroblast growth factor 2 (FGF2). This opens new avenues of exploration for the role of NK cells in remodeling their extracellular environment by modulating the FGF2-FGFR1 axis, which plays a key role in tumor growth, angiogenesis and tissue repair.

immunology↗

bioRxiv2026

ACE-engineered human iPSC-derived neutrophils enhance host defense against multidrug-resistant bacterial infections

Severe neutropenia predisposes patients to life-threatening infections, while donor-dependent granulocyte transfusions are limited by availability and variable cell quality. Here, we engineered human induced pluripotent stem cells (iPSCs) to constitutively or inducibly express angiotensin-converting enzyme (ACE) and differentiated them into functional ACE-engineered neutrophils (ACE-iNeu). ACE expression enhanced granulocytic maturation, reactive oxygen species generation, inflammatory cytokine production, and antimicrobial signaling. ACE-iNeu exhibited enhanced bactericidal activity against methicillin-resistant Staphylococcus aureus and multidrug-resistant Pseudomonas aeruginosa. Following adoptive transfer into neutropenic mice, ACE-iNeu significantly reduced circulating and tissue bacterial burdens. Integrated metabolomic and transcriptomic analyses revealed ACE-associated alterations in adenine nucleotide abundance and developmental and inflammatory pathways. Together, these findings establish ACE engineering as a strategy to enhance the production and antimicrobial function of human iPSC-derived neutrophils and support further preclinical development of engineered granulocyte therapies for severe drug-resistant infections.

immunology↗

bioRxiv2026

Tetravalent dengue mRNA vaccination orchestrates balanced four-serotype immunity with durable memory and protection in mice.

An effective dengue vaccine must establish durable immunity across four dengue virus (DENV) serotypes, evade antibody-dependent enhancement (ADE), and overcome immune imprinting from prior exposure. Here, we developed TetprM-E mRNA-LNP, a tetravalent vaccine comprising LNP-formulated nucleoside-modified mRNAs encoding DENV1-4 precursor membrane-envelope (prM-E) antigens, and evaluated its immunogenicity, durability, protection and breath across serotype-specific immune backgrounds. Three immunization strategies elicited neutralizing titers greater than 1:1500 against each serotype. Passive transfer of immune sera conferred 100% survival and reduced viremia after lethal DENV2 challenge in immunocompromised mice. Vaccination induced DENV envelope (env)-specific CD8+T cells and CD4-dependent germinal-center responses. DENV env-binding antibodies persisted for 34 weeks alongside DENV env-specific memory B cells. Vaccine-elicited sera showed no measurable in vitro ADE. Although monovalent priming initially biased antibody responses, TetprM-E mRNA-LNP vaccination broadened neutralization across DENV1-4 regardless of priming serotype. Together, TetprM-E mRNA-LNP elicits broad, durable, and protective immunity despite serologic constraints from pre-existing immunity.

immunology↗