Ionizing radiation promotes primary ciliogenesis in glioblastoma cells

The aim of this study was to investigate the effects of ionizing radiation (IR) on ciliogenesis of human glioblastoma cells. The glioblastoma cell lines M059K and M059J were exposed to X-ray or carbon ion at different doses, and the incidence and length of primary cilia that emerged were detected by immunofluorescence. A colony formation assay was used to investigate the influence of primary cilia interference by siRNA against IFT88 (siIFT88) on the cellular sensitivity to IR. The results showed that both M059K and M059J harbor primary cilia, with the incidence in M059K and M059J cells at (41.36±4.75)% and (8.07±1.58)%, respectively. The average length of cilia in both cells exceeded 3 μm, with M059J cells having lower frequency and shorter length of primary cilia, and exhibiting a prominently higher radiosensitivity compared to M059K cells. Conversely, X-ray irradiation significantly increased the incidence of primary cilia in M059K cells, and the rate of ciliogenesis reaching approximately 60% when exposed to 10 Gy. Notably, suppression of ciliogenesis by siIFT88 remarkably elevated the radiosensitivity of M059K cells. Moreover, IR-induced ciliogenesis showed dose-dependent and time-response characteristics. In summary, IR promotes ciliogenesis by increasing both number and length of primary cilia, and the obstruction of primary ciliogenesis enhances the radiosensitivity of glioblastoma cells.