Abstract 3612: KAT8/SIRT7-medicated fascin-K41 acetylation/deacetylation regulates tumor metastasis
Authors: Li Da-Jia , Cheng Yin-Wei , Xu Li-Yan , Li En-Min 
Published: April 2023

Background: Although it is not expressed in the normal differentiated epithelial tissue of adult animals, fascin is highly expressed in a variety of cancers, including esophageal cancer, working as an important oncogenic protein. fascin promotes migration and invasion of cancer cells by binding F-actin to promote the formation of filopodia and invadopodia. However, it is not clear how exactly the function of fascin is systematically regulated in cancer cells. There are three regions on the surface of fascin protein that are significantly rich in positively charged lysine and arginine. These regions are now thought to be potential F-actin binding sites. We hypothesize that cancer cells may regulate the function of fascin by post-translational modifications of key amino acids in these three regions, especially by acetylation. Based on this, this study aims to identify acetyltransferases that regulate the acetylation of fascin in esophageal cancer cells and reveal the effect of acetylation on the function of fascin.

Results: 1) Co-IP, pull-down, and immunofluorescence results showed that KAT8 interact with fascin and co-localize in esophageal cancer cells. 2) Mass spectrometry identification of the products of acetylation in vitro revealed that KAT8 acetylates fascin at K41 and K241. By means of Ack41-fascin specific antibodies, further analysis proved that KAT8 acetylated fascin K41. 3) Co-IP and immunofluorescence results showed that SIRT7 interact with fascin and co-localize in esophageal cancer cells, moreover, treatment of cells with SIRT7-specific inhibitor significantly increased the level of AcK41-fascin, and however, overexpressing SIRT7 reduces the level of AcK41-fascin. 4) Immunohistochemical results showed that the level of AcK41-fascin was lower in esophageal cancer tissues of patients with lymph node metastasis; Analysis of overall survival and tumor-free survival curves showed that patients with high levels of AcK41-fascin had a better prognosis. 5) Cell wound healing and transwell assay showed that fascin K41 residue mimics acetylation inhibit the movement and invasion of esophageal cancer cells. 6) Furthermore, in vitro F-actin binding assays showed that mutations mimicing acetylation of K41 inhibited the activity of fascin bunding F-actin. 7) Immunofluorescence assay showed that fascin K41 residue mimics acetylation inhibited fascin's ability to promote filopodia and invadopodia formation in esophageal cancer cells.

Conclusions: 1) KAT8 is an acetyltransferase that catalyzes fascin K41 acetylation in esophageal cancer cells, while SIRT7 decides to catalyze AcK41-fascin deacetylation. 2) SIRT7-mediated deacetylation of AcK41-fascin promotes the formation of filopodia and invadopodia, which promotes the invasion and metastasis of esophageal cancer cells. (This work was supported by grants from the National Natural Science Foundation of China (No.81872372 and 81902469))

Citation Format: Da-Jia Li, Yin-Wei Cheng, Li-Yan Xu, En-Min Li. KAT8/SIRT7-medicated fascin-K41 acetylation/deacetylation regulates tumor metastasis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3612.