Abstract 5240: S-phase cyclinA associated protein in the ER(SCAPER)rs3812908 T>C promotes the nuclear translocation of CyclinA2 and enhances DNA damage repair in radioresistance of colorectal cancer

Abstract Radiotherapy resistance is still an obstacle of improving the survival of patients with locally advanced colorectal cancer. In this study, whole-exome sequencing and targeted sequencing were preformed on colorectal cancer tumor tissue samples which were colloected from multiple centers, and the pathologic complete response predictive model PGS-LARC(Prediction Genotype Signature for Locally Advanced Rectal Cancer) was established. A candidate SNV-SCAPER rs3812908 T>C was screened using this model. To investigate the relationship between SCAPER rs3812908 T>C and radiosensitivity of colorectal cancer, targeted sequencing was performed and the results revealed that proportion of CC genotype was significantly higher in resistant sequencing cohort than in sensitive ones (30% vs. 22%). And Immunohistochemistry (IHC) results revealed that SCAPER protein expressed less in CC genotype colorectal cancer tissues than in TT genotype. Here, the cell proliferation results showed that SCAPER-KD cells and SCAPER rs3812908 CC cells were more radioresistant than SCAPER-NC and TT cells. Furthermore, the immunofluorescence assay showed SCAPER rs3812908 T>C promoted translocation of S phase associated protein-Cyclin A2 into nucleus and western blotting results showed that the phosphorylation of ERK and JNK(p-ERK and p-JNK) increased significantly in SCAPER CC cells, and the protein p-ATR, p-ATM, p-CDC25C and CDC25A related to homologous recombination repair were also increased in SCAPER-KD and SCAPER CC cells.Taken together, the SCAPER gene rs3812908 T>C plays an important role in radioresistance of colorectal cancer. The SNV of SCAPER rs3812908 T>C significantly promotes Cyclin A2 nuclear translocation, activates the MAPKs pathway, and increases homologous recombination repair, and finally leads to radioresistance. Citation Format: Hai-na Yu, Ting Jiang, Shuang Liu, Yan Yuan, Shao-yan Xi, Zhi-wei Guo, Yuan-hong Yuan, Yan Li, Wei-wei Xiao. S-phase cyclinA associated protein in the ER(SCAPER)rs3812908 T>C promotes the nuclear translocation of CyclinA2 and enhances DNA damage repair in radioresistance of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5240.