Eno1 Lactylation as a Promising Predictive Biomarker and Therapeutic Target for Escc Metastasis

Background Esophageal squamous cell carcinoma (ESCC) is frequently associated with lymph nodes metastasis (LNM). Even in the pT1 stage, the nodal metastasis risk is around 4% for pT1a ESCC and 30% for pT1b ESCC patients. In order to improve the survival outcomes of ESCC patients, new predictive biomarker and therapeutic target are required for ESCC metastasis. Aerobic glycolysis is a common phenomenon of malignancy and produces large amounts of lactate. Lactate-mediated lysine lactylation (Kla) is essential for cancer progression. However, the role and mechanism of Kla in esophageal squamous cell cancer (ESCC) remain elusive. Methods Fourteen tissue samples were prospectively collected from ESCC patients who underwent radical surgery without neoadjuvant therapy. The samples were categorized into ESCC-LNM and ESCC-non-LNM (n = 7/group). The levels of pan-Kla in EC tissues were firstly confirmed via western blotting. Lactylome analysis was then carried out to assess proteins with significantly different lactylation between ESCC patients with and without LNM. Furthermore, the results of LC–MS/MS were verified using ESCC cells and primary ESCC specimens. This research study was authorized by the Ethical Board of our hospital. All the patients were informed about the study and their consents were acquired. Results The lactylome analysis revealed that 48 Kla sites in 29 proteins were substantially downregulated, whereas 91 Kla sites in 60 proteins were markedly upregulated in ESCC-LNM tissues compared to ESCC-non-LNM tissues. 46.07% of differentially lactylated proteins were localized in the cytoplasm, whereas 19.2% were found in the nucleus, indicating both histone and non-histone Kla modulate ESCC metastasis. Intriguingly, the ENO1 protein’s Kla level in ESCC cells was positively correlated with cell migration ability. TSA multiplex immunofluorescence staining demonstrated ESCC-LNM tissues had higher ENO1 lactylation levels than ESCC-non-LNM tissues (pT2N1 vs. pT2N0 and pT3N1 vs. pT3N0). Conclusion This research study revealed that Kla is crucially involved in ESCC metastasis. ENO1 lactylation potentially promotes esophageal cancer pathogenesis and it may be a promising predictive biomarker and treatment target for ESCC metastasis.