Open Access
ARTICLE
Lactic Acid Drives ESM1 to Attenuate DNA Damage and CD8+ T Cell Infiltration in Cancer
Yingzheng Tan1,#, Jiao Xiao2,#, Liyun Tang3,4,#, Jian Wan3,#, Tian Zeng3, Wenchao Zhou3, Xueru Liu3, Xun Chen3,5,*, Yukun Li3,*
1 Department of Infectious Disease, Zhuzhou Hospital Affiliated to Xiangya School of Medicine, Central South University, Zhuzhou, China
2 Affiliated Nanhua Hospital, University of South China, Hengyang, China
3 Tumor ImmunoMetabolism Institute (TIMI), The Affiliated Zhuzhou Hospital Xiangya Medical College, Central South University, Zhuzhou, China
4 Department of Medical Oncology, The Third People’s Hospital of Yongzhou, Yongzhou, China
5 Department of Hepatological Surgery, Zhuzhou Hospital Affiliated to Xiangya School of Medicine, Central South University, Zhuzhou, China
* Corresponding Author: Xun Chen. Email: 
; Yukun Li. Email: 
# These authors contributed equally to this work
Oncology Research https://doi.org/10.32604/or.2026.071536
Received 06 August 2025; Accepted 19 January 2026; Published online 05 February 2026
Abstract
Background: Lactate, as a critical byproduct of tumor metabolic reprogramming, plays an important role in DNA damage repair and tumor immune infiltration. This work aims to elucidate the molecular mechanisms by which lactate promotes tumor DNA damage repair (DDR) and subsequent immune evasion. Methods: Hepatocellular carcinoma (HCC), lung adenocarcinoma (LUAD), and ovarian cancer (OC) cells with cisplatin-induced DNA damage were treated with lactate at a concentration gradient, Endothelial cell-specific molecule 1 (ESM1) shRNA, ESM1 overexpression plasmid, or the Protein Kinase B (AKT) Serine/Threonine Kinase 1 (Akt1) inhibitor LY294002. Proliferation, apoptosis, and DNA damage levels were assessed using 5-ethynyl-2′-deoxyuridine (EdU) staining, flow cytometry-based apoptosis assay, and comet assay. Western blot (WB), Polymerase Chain Reaction (PCR), and immunofluorescence (IF) were employed to evaluate the effects of lactate on the expression of ESM1, Akt1, and Cyclic GMP-AMP Synthase (cGAS) pathway-related proteins in cancer cells. Xenograft tumor models were established using ESM1 whole-gene knockout mice, and Cluster of Differentiation 8 Positive (CD8+) T cell infiltration and apoptotic levels in tumors were detected via flow cytometry. Immunohistochemistry (IHC) was performed to examine the expression of ESM1, double-stranded DNA (dsDNA), and CD8 in tumor patient samples, followed by correlation analysis. Results: This study demonstrates that lactate increases ESM1 mRNA and protein expression in a concentration-dependent manner and reduces DNA damage in tumor cells. Lactate suppresses DDR by activating the Akt1 signaling pathway via ESM1 and further inhibits the cGAS pathway, thereby downregulating the transcription of chemokines and pro-inflammatory factors. In vivo experiments confirm that ESM1 knockout promotes CD8+ T cell infiltration into tumors and induces apoptosis. Analysis of tumor patient samples further validates the negative correlation between ESM1 and CD8+ T cell levels in cancer patients. Conclusion: In summary, lactate activates the Akt1-Murine Double Minute 2 (MDM2)-p53 pathway via ESM1 to suppress DDR, while the reduction of DDR-generated dsDNA inactivates the cyclic GMP-AMP synthase–Stimulator of Interferon Genes (cGAS-STING) pathway, thereby inhibiting CD8+ T cell immune infiltration.
Keywords
Endothelial cell-specific molecule 1; DNA damage response; lactic acid; CD8 T cell; cancer immunity
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