SIRT6 and esophageal squamous cell carcinoma: To verify whether SENP1 directly targets de-SUMOylation of SIRT6 in ESCC cells, we conducted a co-immunoprecipitation (co-IP) assay and found that SUMO-conjugated SIRT6 was more enriched in shSENP1 than shNC cells (Fig. 5C).