The Role And Mechanism Of Sp1 On The Radiosensitivity Of Cervical Cancer Cell Lines

Background and purposeCervical cancer is the most frequent gynaecological malignancy in the world.Radiation therapy is one of the main therapies of cervical cancer,80%of patients accepted radiotherapy as radical or adjuvant therapy,with 30-50%of the patients with advanted cancer ended in treatment failure because of radiation resistance.Therefore,improving the radiosensitivity is of great significance the treatment for patients with late-stage cervical cancer.Recent studies found that some oncogene,transcription factors and other closely related with the radiosensitivity of cervical cancer,but there's not one opinion about unique and reliable marker of it still.Therefore,in-depth study of a marker and relevant mechanism is essential for development of cervical cancer radiotherapy.Spl,a DNA binding protein with specific sequence,initially identified as a transcription factor,participated in the regulation of the radiosensitivity of some tumors,and it is closely related to the progress of cervical cancer.Therefore,Spl may be an important factor in the regulation of the radiosensitivity of cervical cancer.In this study,we found that Spl expression was increased in response to IR,and by silencing and overexpessing the expression of Spl in cervical cancer cell lines,we vestified that Sp1 downgegulated the radiosensitivity of cervical cancer by decreasing radiation-inuced G2/M arrest through upregulating CDK1 in cervical cancer cells.This study will be divided into 4 parts.Chapter 1 The relationship between Spl and the radiotherapy of cervical cancerObjectiveTo investigate the correlation between Sp1 and cervical cancer radiotherapyMethodsThe expression Spl in irradiated cervical cancer cell lines was detected by RT-PCR and western blotting.ResultsSpl expression was dose-dependent increased in response to IRConclusionSpl is closely associated with cervical cancer radiotherapy.Chapter 2 The effect of Spl on the radiosensitivity of cervical cancerObjectiveTo explore the role of Sp1 on the radiosensitivity of cervical cancer.MethodsEstablished Sp1 silenced and overexpressed stable lines by lentivirus-mediated vetors,and detected the effect of Sp1 on the radiosensitivity of cervical cancer cell lines by Colony-formation assay and Cell Counting Kit 8.ResultsSilencing the expression of Spl enhanced radiosensitivity,and overexpression of Spl attenuates cellular response to radiationConclusionSpl downregulated the radiosensitivity of cervical cancer cells.Chapter 3 Spl regulated the radiosensitivity of cervical cancer by effecting radiation-related cell cycle arrest.ObjectiveTo explore the effect of Sp1 on the regulation of cell cycle in cervical cancer cell lines.MethodsFlow cytometry was used to study the effect of Spl on radiation-related cell cycle arrest.ResultsSilence of Sp1 increased radiation-related G2/M arrest,inversely,overexpression of Spl diminished radiation-related G2/M arrest.ConclusionSpl downregulated the radiosensitivity of cervical cancer by decreasing radiation-related G2/M arrest.Chapter 4 Spl effected the radiosensitivity of cervical cancer through targeting CDK1 in cervical cancer cells.ObjectiveTo study the mechansim of Spl on the regulation of radiosensitivity of cervical cancer cell lines.Methods1.RT-PCR and Western blotting were measured the expression of genes related with G2/M arrest.2.Rescue experiments were used to vestified Sp1 regulated the radiosensitivity of cervical cancer cells by effecting CDK1.3.Dual luciferase activity assay was used to sutdy whether Spl influenced on the promoter of CDK1.Results1.Silenced Spl markedly reduced the expression of CDK1 in cervical cancer cells,inversely,Spl overexpression greatly up regulated CDK1.2.The depressed radiosensitivity induced by overexpressed Sp1 could be revered by silencing the expression of CDK1.3.Overexpressed Spl significantly rised the luciferase activity of the promoter of CDK1.ConclusionSpl downgegulated the radiosensitivity of cervical cancer through upregulating CDK1 in cervical cancer cells directly.Summary1.Spl is closely associated with cervical cancer radiotherapy,and silencing/overexpressing the expression of Spl will upregulate/downregulate the radio-sensitivity of cervical cancer cells.2.Spl downregulated the radiosensitivity of cervical cancer by decreasing radiation-related G2/M arrest.3.Sp1 downregulated the radiosensitivity of cervical cancer through upregulating CDK1 in cervical cancer cells directly.THE INNOVATION OF THIS PROJECT1.The first demonstration of the role of Spl on the radiosensitivity of cervical cancer cells2.Proposed a new regulation mechanism participated in the radiosensitivity of cervical cancer cell,Spl downregulated the radiosensitivity of cervical cancer through upregulating CDK1 in cervical cancer cells directly.