Fig 2: XRCC5 regulates TMZ sensitivity exists in other types of GBM cells. (A) mRNA expression level of XRCC5 in the M059K cell line transfected with pCMV–XRCC5 overexpression vector or pCMV was determined using reverse transcription-quantitative PCR. *P<0.05 compared with pCMV group. (B) The M059K cells transfected with pCMV–XRCC5 overexpression vector or pCMV were treated with increasing doses of TMZ (0-250 µM) for 48 h and subsequently evaluated using a MTT assay. *P<0.05 compared with pCMV group. (C) The DBTRG-05MG and DBTRG-05MG-R cells were treated with increasing concentrations of TMZ (0-1,000 µM) for 48 h and cell viability was determined using a MTT assay. *P<0.05 compared with DBTRG-05MG cells. (D) Dose-dependent effects of TMZ on the protein expression levels of cleaved caspase-3 and cleaved PARP in DBTRG-05MG and DBTRG-05MG-R cells were analyzed using western blot analysis (right panel) and quantified using densitometry (left panel). *P<0.05 compared with untreated control. #P<0.05 compared with DBTRG-05MG cells. (E) Dose-dependent effects of TMZ on the protein expression level of XRCC5 in the DBTRG-05MG and DBTRG-05MG-R cells were analyzed using western blot analysis (left panel) and quantified using densitometry (right panel). a-Tubulin was used as loading control. *P<0.05 compared with untreated control. (F) Western blot analysis was to determine the XRCC5 protein expression level in DBTRG-05MG and DBTRG-05MG-R cells (left panel) and the data was subsequently quantified using densitometry (right panel). *P<0.05 compared with DBTRG-05MG cells. TMZ, temozolomide.

Fig 3: The role of linc00312 in regulating radiosensitivity of NPC.linc00312 directly binds to DNA-PKcs, hinders the recruitment of DNA-PKcs to Ku80, and inhibits phosphorylation of AKT–DNA–PKcs axis, therefore inhibiting the DNA damage signal sensation and transduction in the NHEJ repair pathway. In addition, linc00312 impairs DNA repair and cell cycle control by suppressing MRN–ATM–CHK2 signal and ATR–CHK1 signal.

Fig 4: The degradation of XRCC5 was ubiquitin/proteasome-dependent and DTX3 could promote the ubiquitination of XRCC5. (A) The negative co-expression relationship between DTX3 and XRCC5 in PTC database of TCGA. (B) Cells were treated with 10 µM MG-132 for 6 h and whole cell lysates were prepared to western blot with XRCC5 antibody. Lower panel: Integrated optical density (IOD) of XRCC5 protein was presented as relative expression level after normalization with internal control GAPDH. (C) Cells were treated with 10 µM MG-132 for 6 h and whole cell lysates were subjected to immunoprecipitation with either XRCC5 antibody or normal IgG antibody. Ubiquitin antibody was used as the primary antibody to western blot.

Fig 5: Immunoprecipitation followed by Western blot was performed to visualize specific proteins recognized by autoantibodies from patient sera. (a) Immunoprecipitation of Ku70 protein. (b) Immunoprecipitation of Ku80 protein. (c) Immunoprecipitation of PL-7 protein. Molecular weight is indicated on the left-hand side of each figure.