SUMO1 Modification Stabilizes TET3 Protein and Increases Colorectal Cancer Radiation Therapy Sensitivity

Fengting Liu; Ya Ma; Hao Sun; Hui Cai; Xin Liang; Chang Xu; Liqing Du; Yan Wang; Qiang Liu

doi:10.1016/j.ijrobp.2023.05.037

SUMO1 Modification Stabilizes TET3 Protein and Increases Colorectal Cancer Radiation Therapy Sensitivity

Int J Radiat Oncol Biol Phys. 2023 Nov 15;117(4):942-954. doi: 10.1016/j.ijrobp.2023.05.037. Epub 2023 May 25.

Authors

Fengting Liu¹, Ya Ma², Hao Sun³, Hui Cai³, Xin Liang⁴, Chang Xu³, Liqing Du³, Yan Wang³, Qiang Liu³

Affiliations

¹ Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; Department of Radiation Oncology, The Afliated Cancer Hospital of Zhengzhou University, No. 127 Dongming Road, Zhengzhou 450008, Henan, China.
² Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.
³ Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China.
⁴ School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Center for Disease Control and Prevention, Tianjin, China.

PMID: 37244630
DOI: 10.1016/j.ijrobp.2023.05.037

Abstract

Purpose: The aim of this work was to explore the role and mechanism of active DNA demethylase in colorectal cancer (CRC) radiation sensitization and better understand the function of DNA demethylation in tumor radiosensitization.

Methods and materials: Tested the effect of ten-eleven translocation 3 (TET3) overexpression on the sensitivity of CRC to radiation therapy through G2/M arrest, apoptosis, and clonogenic suppression. TET3 knockdown HCT 116 and TET3 knockdown LS 180 cell lines were constructed by siRNA technology, and the effect of exogenous knockdown of TET3 on radiation-induced apoptosis, cell cycle arrest, DNA damage, and clone formation in CRC cells were detected. The co-localization of TET3 and small ubiquitin-like modifier 1 (SUMO1), SUMO2/3 was detected by immunofluorescence and cytoplasmic-nuclear extraction, and the interaction between TET3 and SUMO1, SUMO2/3 was detected by a coimmunoprecipitation assay.

Results: The malignant phenotype and radiosensitivity of CRC cell lines were favorably linked with TET3 protein and mRNA expression. TET3 is upregulated in 23 of the 27 tumor types investigated, including colon cancer. TET3 was shown to correlate with the CRC pathologic malignancy grade positively. Overexpression of TET3 in CRC cell lines increased radiation-induced apoptosis, G2/M phase arrest, DNA damage, and clonal suppression in vitro. The binding region of TET3 and SUMO2/3 was located at 833-1795 AA except for K1012, K1188, K1397, and K1623. SUMOylation of TET3 increased the stability of the TET3 protein without changing its nuclear localization.

Conclusions: We report the sensitizing role of TET3 protein in the radiation of CRC cells, depending on SUMO1 modification of TET3 at the lysine sites (K479, K758, K1012, K1188, K1397, K1623), in turn stabilizing TET3 expression in the nucleus and subsequently increasing the sensitivity of CRC to radiation therapy. Together, this study highlights the potentially critical role of TET3 SUMOylation in radiation regulation, which may contribute to an enhanced understanding of the relationship between DNA demethylation and radiation therapy.