Loss of NEIL3 activates radiotherapy resistance in the progression of prostate cancer

Objective:To explore the genetic changes in the progression of castration-resistant prostate cancer(CRPC)and neuroendocrine prostate cancer(NEPC)and the reason why these cancers resist existing therapies.Methods:We employed our CRPC cell line microarray and other CRPC or NEPC datasets to screen the target gene NEIL3.Lentiviral transfection and RNA interference were used to construct overexpression and knockdown cell lines.Cell and animal models of radiotherapy were established by using a medical electron linear accelerator.Flow cytometry was used to detect apoptosis or cell cycle progression.Western blot and qPCR were used to detect changes in the protein and RNA levels.Results:TCGA and clinical patient datasets indicated that NEIL3 was downregulated in CRPC and NEPC cell lines,and NEIL3 was correlated with a high Gleason score but a good prognosis.Further functional studies demonstrated that NEIL3 had no effect on the proliferation and migration of PCa cells.However,cell and animal radiotherapy models revealed that NEIL3 could facilitate the radiotherapy sensitivity of PCa cells,while loss of NEIL3 activated radiotherapy resistance.Mechanistically,we found that NEIL3 negatively regulated the expression of ATR,and higher NEIL3 expression repressed the ATR/CHK1 pathway,thus regulating the cell cycle.Conclusions:We demonstrated that NEIL3 may serve as a diagnostic or therapeutic target for therapy-resistant patients.

Polymorphism in the Hsa-miR-4274 seed region influences the expression of PEX5 and enhances radiotherapy resistance in colorectal cancer

Identifying biomarkers for predicting radiotherapy efficacy is crucial for optimizing personalized treatments.We previously reported that rs1553867776 in the miR-4274 seed region can predict survival in patients with rectal cancer receiving postoperative chemoradiation therapy.Hence,to investigate the molecular mechanism of the genetic variation and its impact on the radiosensitivity of colorectal cancer(CRC),in this study,bioinformatics analysis is combined with functional experiments to confirm peroxisomal biogenesis factor 5(PEX5)as a direct target of miR-4274.The miR-4274 rs1553867776 variant influences the binding of miR-4274 and PEX5 mRNA,which subsequently regulates PEX5 protein expression.The interaction between PEX5 and Ku70 was verified by co-immunoprecipitation and immunofluorescence.A xenograft tumor model was established to validate the effects of miR-4274 and PEX5 on CRC progression and radiosensitivity in vivo.The overexpression of PEX5 enhances radiosensitivity by preventing Ku70 from entering the nucleus and reducing the repair of ionizing radiation(IR)-induced DNA damage by the Ku70/Ku80 complex in the nucleus.In addition,the enhanced expression of PEX5 is associated with increased IR-induced ferroptosis.Thus,targeting this mechanism might effectively increase the radiosensitivity of CRC.These findings offer novel insights into the mechanism of cancer radioresistance and have important implications for clinical radiotherapy.

Research of the relationship between radiotherapy and microRNAs

MicroRNAs(miRNAs) are endogenous short non-coding RNAs,and play a pivotal role in regulating a variety of cellular processes,including proliferation and apoptosis,both of which are cellular responses to radiation treatment.In response to radiation,multiple miRNAs show altered expression,which act as oncogenes or tumor suppressors.Recent evidence has also shown that some miRNAs have radiotherapy sensitization or radiation resistance role in malignant tumors.This review focuses on analysis of these characteristics and mechanisms of miRNAs,and will provide some insight into the therapeutic application of radiation.