Although
radiation therapy has recently made great advances in
cancer treatment, the majority of patients diagnosed with
pancreatic cancer (PC) cannot achieve satisfactory outcomes due to intrinsic and acquired radioresistance. Identifying the molecular mechanisms that impair the efficacy of
radiotherapy and targeting these pathways are essential to improve the radiation response of PC patients. Our goal is to identify sensitive targets for
pancreatic cancer radiotherapy (RT) using the kinome-wide CRISPR-Cas9 loss-of-function screen and enhance the
therapeutic effect through the development and application of targeted inhibitors combined with
radiotherapy. We transduced
pancreatic cancer cells with a
protein kinase library; 2D and 3D library cells were irradiated daily with a single dose of up to 2 Gy for 4 weeks for a total of 40 Gy using an X-ray generator. Sufficient
DNA was collected for next-generation deep sequencing to identify candidate genes. In this study, we identified several cell cycle checkpoint
kinases and DNA damage related
kinases in 2D- and 3D-cultivated cells, including DYRK1A, whose loss of function sensitizes cells to
radiotherapy. Additionally, we demonstrated that the
harmine-targeted suppression of DYRK1A used in conjunction with
radiotherapy increases
DNA double-strand breaks (DSBs) and impairs homologous repair (HR), resulting in more
cancer cell death. Our results support the use of CRISPR-Cas9 screening to identify new therapeutic targets, develop radiosensitizers, and provide novel strategies for overcoming the tolerance of
pancreatic cancer to
radiotherapy.