Sp1 Upregulation Bolsters the Radioresistance of Glioblastoma Cells by Promoting Double Strand Breaks Repair

Overview

Journal Int J Mol Sci

Publisher MDPI

Specialties Biochemistry
Chemistry
Molecular Biology

Date 2023 Jul 14

PMID 37445835

Authors

Xiongxiong Liu

Chao Sun

Qiqi Wang

Ping Li

Ting Zhao

Qiang Li

Affiliations

Soon will be listed here.

Abstract

Radioresistance remains a critical obstacle in the clinical management of glioblastoma (GBM) by radiotherapy. Therefore, it is necessary to explore the molecular mechanisms underlying radioresistance to improve patient response to radiotherapy and increase the treatment efficacy. The present study aimed to elucidate the role of specificity protein 1 (Sp1) in the radioresistance of GBM cells. Different human GBM cell lines and tumor-bearing mice were exposed to ionizing radiation (IR). Cell survival was determined by the colony formation assay. The expression of genes and proteins in the cells and tissues was analyzed by RT-PCR and western blotting, respectively. The γ-H2AX, p-Sp1 and dependent protein kinase catalytic subunit (DNA-PKcs phospho S2056) foci were analyzed by immunofluorescence. Apoptotic rates were measured by flow cytometry. Sp1 was upregulated after IR in vitro and in vivo and knocking down Sp1-sensitized GBM cells to IR. Sp1 activated the DNA-PKcs promoter and increased its expression and activity. Furthermore, the loss of Sp1 delayed double-strand breaks (DSB) repair and increased IR-induced apoptosis of GBM cells. Taken together, IR upregulates Sp1 expression in GBM cells, enhancing the activity of DNA-PKcs and promoting IR-induced DSB repair, thereby leading to increased radioresistance.

Citing Articles

Combinatorial functionomics identifies HDAC6-dependent molecular vulnerability of radioresistant head and neck cancer.

Chan S, Yeo C, Hong B, Tan E, Beh C, Yeo E Exp Hematol Oncol. 2025; 14(1):5.

PMID: 39800760 PMC: 11727331. DOI: 10.1186/s40164-024-00590-8.

Genistein Implications in Radiotherapy: Kill Two Birds with One Stone.

Liu X, Zheng T, Bao Y, Li P, Zhao T, Liu Y Molecules. 2025; 30(1.

PMID: 39795243 PMC: 11723059. DOI: 10.3390/molecules30010188.

SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression.

Shan L, Wang W, Du L, Li D, Wang Y, Xie Y Proc Natl Acad Sci U S A. 2024; 121(29):e2401834121.

PMID: 38976739 PMC: 11260144. DOI: 10.1073/pnas.2401834121.

References

Santivasi W, Xia F . Ionizing radiation-induced DNA damage, response, and repair. Antioxid Redox Signal. 2013; 21(2):251-9. DOI: 10.1089/ars.2013.5668. View

Liu X, Sun C, Jin X, Li P, Zheng X, Zhao T . Genistein sensitizes sarcoma cells in vitro and in vivo by enhancing apoptosis and by inhibiting DSB repair pathways. J Radiat Res. 2016; 57(3):227-37. PMC: 4915536. DOI: 10.1093/jrr/rrv091. View

Iwahori S, Shirata N, Kawaguchi Y, Weller S, Sato Y, Kudoh A . Enhanced phosphorylation of transcription factor sp1 in response to herpes simplex virus type 1 infection is dependent on the ataxia telangiectasia-mutated protein. J Virol. 2007; 81(18):9653-64. PMC: 2045397. DOI: 10.1128/JVI.00568-07. View

Zhang J, Zhang H, Wang H, Li Y, Liu G, Xing S . Down-regulation of Sp1 suppresses cell proliferation, clonogenicity and the expressions of stem cell markers in nasopharyngeal carcinoma. J Transl Med. 2014; 12:222. PMC: 4132216. DOI: 10.1186/s12967-014-0222-1. View

Deycmar S, Faccin E, Kazimova T, Knobel P, Telarovic I, Tschanz F . The relative biological effectiveness of proton irradiation in dependence of DNA damage repair. Br J Radiol. 2019; 93(1107):20190494. PMC: 7066963. DOI: 10.1259/bjr.20190494. View

Liu X, Li P, Hirayama R, Niu Y, Liu X, Chen W . Genistein sensitizes glioblastoma cells to carbon ions via inhibiting DNA-PKcs phosphorylation and subsequently repressing NHEJ and delaying HR repair pathways. Radiother Oncol. 2018; 129(1):84-94. DOI: 10.1016/j.radonc.2018.04.005. View

Nishida Y, Mizutani N, Inoue M, Omori Y, Tamiya-Koizumi K, Takagi A . Phosphorylated Sp1 is the regulator of DNA-PKcs and DNA ligase IV transcription of daunorubicin-resistant leukemia cell lines. Biochim Biophys Acta. 2014; 1839(4):265-74. DOI: 10.1016/j.bbagrm.2014.02.004. View

Meng W, Palmer J, Siedow M, Haque S, Chakravarti A . Overcoming Radiation Resistance in Gliomas by Targeting Metabolism and DNA Repair Pathways. Int J Mol Sci. 2022; 23(4). PMC: 8880405. DOI: 10.3390/ijms23042246. View

Iwahori S, Yasui Y, Kudoh A, Sato Y, Nakayama S, Murata T . Identification of phosphorylation sites on transcription factor Sp1 in response to DNA damage and its accumulation at damaged sites. Cell Signal. 2008; 20(10):1795-803. DOI: 10.1016/j.cellsig.2008.06.007. View

10.

Han X, Xue X, Zhou H, Zhang G . A molecular view of the radioresistance of gliomas. Oncotarget. 2017; 8(59):100931-100941. PMC: 5725073. DOI: 10.18632/oncotarget.21753. View

11.

Olofsson B, Kelly C, Kim J, Hornsby S, Azizkhan-Clifford J . Phosphorylation of Sp1 in response to DNA damage by ataxia telangiectasia-mutated kinase. Mol Cancer Res. 2008; 5(12):1319-30. DOI: 10.1158/1541-7786.MCR-07-0374. View

12.

Ou A, Yung W, Majd N . Molecular Mechanisms of Treatment Resistance in Glioblastoma. Int J Mol Sci. 2021; 22(1). PMC: 7794986. DOI: 10.3390/ijms22010351. View

13.

Hosoi Y, Watanabe T, Nakagawa K, Matsumoto Y, Enomoto A, Morita A . Up-regulation of DNA-dependent protein kinase activity and Sp1 in colorectal cancer. Int J Oncol. 2004; 25(2):461-8. View

14.

Aldoghachi A, Aldoghachi A, Breyne K, Ling K, Cheah P . Recent Advances in the Therapeutic Strategies of Glioblastoma Multiforme. Neuroscience. 2022; 491:240-270. DOI: 10.1016/j.neuroscience.2022.03.030. View

15.

Olive P . Retention of γH2AX foci as an indication of lethal DNA damage. Radiother Oncol. 2011; 101(1):18-23. DOI: 10.1016/j.radonc.2011.05.055. View

16.

Bu Y, Suenaga Y, Ono S, Koda T, Song F, Nakagawara A . Sp1-mediated transcriptional regulation of NFBD1/MDC1 plays a critical role in DNA damage response pathway. Genes Cells. 2008; 13(1):53-66. DOI: 10.1111/j.1365-2443.2007.01144.x. View

17.

Aiyappa-Maudsley R, Chalmers A, Parsons J . Factors affecting the radiation response in glioblastoma. Neurooncol Adv. 2022; 4(1):vdac156. PMC: 9617255. DOI: 10.1093/noajnl/vdac156. View

18.

Grinstein E, Jundt F, Weinert I, Wernet P, Royer H . Sp1 as G1 cell cycle phase specific transcription factor in epithelial cells. Oncogene. 2002; 21(10):1485-92. DOI: 10.1038/sj.onc.1205211. View

19.

Liu X, Sun C, Jin X, Li P, Ye F, Zhao T . Genistein enhances the radiosensitivity of breast cancer cells via G₂/M cell cycle arrest and apoptosis. Molecules. 2013; 18(11):13200-17. PMC: 6269669. DOI: 10.3390/molecules181113200. View

20.

Nichols A, Itoh T, Zolezzi F, Hutsell S, Linn S . Basal transcriptional regulation of human damage-specific DNA-binding protein genes DDB1 and DDB2 by Sp1, E2F, N-myc and NF1 elements. Nucleic Acids Res. 2003; 31(2):562-9. PMC: 140516. DOI: 10.1093/nar/gkg152. View