Lactate Drives Immune Evasion in Pancreatic Cancer via TRMT6-SIRT5 Axis

Lactate, long regarded as a metabolic waste product, appears to play an active role in helping pancreatic ductal adenocarcinoma (PDAC) evade the immune system, according to a study published in Cancer & Metabolism. The research, released online on 18 August 2026 as an open-access article, reports that lactate abundant in the pancreatic tumor microenvironment triggers a chain of molecular events that boosts tumor metabolism and raises expression of PD-L1, the protein that shields cancer cells from T-cell attack. The work may help explain why PDAC, a disease with poor prognosis, responds so poorly to immune checkpoint inhibitors.

The team, led by Fei Chen and Yiyu Shen with senior author Shuying Yang, used PDAC cell models exposed to lactate together with xenograft mice, applying N1-methyladenosine (m1A) RNA immunoprecipitation, ribosome profiling, and transcriptome analyses. Their experiments centered on the TRMT6-SIRT5 axis. TRMT6 is an enzyme that installs m1A modifications on RNA; the study found that lactate significantly enhanced this modification, increasing translation of key metabolic enzymes and driving metabolic reprogramming in the cancer cells. In parallel, lactate activated SIRT5-mediated desuccinylation, a process that boosted the activity of TCA cycle enzymes and shifted cells toward oxidative metabolism.

According to the results section of the paper, this lactate-driven pathway also upregulated PD-L1 through the TRMT6-SIRT5 axis and enhanced CDK4/6 signaling, together promoting immune evasion. The authors then tested a therapeutic combination in mice: CDK4/6 inhibitors paired with blockers of lactate metabolism. In the xenograft model, the combination reduced PD-L1 expression, restored T cell function, and improved the efficacy of anti-PD-1 immunotherapy. The authors conclude that lactate may promote metabolic reprogramming and immune evasion in PDAC through this axis, linking metabolism, epigenetic regulation, and antitumor immunity, and that combining CDK4/6 inhibition with lactate blockade may provide a rationale for improving immunotherapy responses in pancreatic cancer.

Important caveats apply to these findings. The mechanistic work was conducted in cell models and in mice, not in human patients, so the reported restoration of T-cell function and improved anti-PD-1 efficacy are preclinical observations rather than demonstrated clinical benefits. The article is also being shared early as a peer-reviewed, accepted manuscript carrying a permanent DOI; the publishers note that this version is subject to further edits and will be replaced by the final Version of Record. Even so, the study offers a testable model for why pancreatic tumors are so immunologically resistant: a single metabolite, lactate, appears to simultaneously rewire core energy metabolism and suppress the immune recognition of tumor cells. If the TRMT6-SIRT5 mechanism holds up in human tissue and clinical testing, pairing lactate metabolism blockers with CDK4/6 inhibitors and checkpoint immunotherapy could become a strategy worth evaluating in pancreatic cancer, a disease where new treatment options remain urgently needed.

Subject of Research: How lactate in the pancreatic tumor microenvironment promotes metabolic reprogramming and immune evasion in PDAC through the TRMT6-SIRT5 axis.

Article Title: Integrating metabolism and immunity: targeting lactate-mediated mechanisms in PDAC

Article References: Chen, F., Shen, Y., Liu, X., Chen, M., Song, Z., Hu, L., & Yang, S. (2026). Integrating metabolism and immunity: targeting lactate-mediated mechanisms in PDAC. Cancer & Metabolism. https://doi.org/10.1186/s40170-026-00452-3

Image Credits: AI Generated

DOI: 10.1186/s40170-026-00452-3

Keywords: pancreatic cancer, PDAC, lactate, TRMT6, SIRT5, PD-L1, immune evasion, CDK4/6 inhibitors, immunotherapy, metabolic reprogramming, tumor microenvironment, preclinical study