Fig. 6: CRY1 levels modulate the behavior of cancer cells and their response to treatment.

A Elapsed days for a second tumor event in cells stratified for its CRY1 levels in two categories: High (red line) or low (blue line). Data from TCGA. The number of tumor samples is indicated. Statistical significance was analyzed using Kaplan-Meier test. B Pan-cancer data from the TCGA were separated according the levels of CRY1 and the appearance of mutations associated with the mutational signature 3, caused by defective HDR, was scored and represented. Statistical significance was analyzed using an unpaired one-sided Student’s T-test. C Survival of breast cancer patients treated with radiotherapy according the CRY1 levels of the tumor cells. Data from TCGA. Other details as in A. Statistical significance was analyzed using Kaplan-Meier test. D Same as C but regarding CCAR2 levels. Statistical significance was analyzed using Kaplan-Meier test. E Nude mice were grafted with HCT116 cells depleted for CRY1 on the right flank and control cells on the left flank. Mice were treated with etoposide as indicated in the method section. The average and standard deviation of tumor volume of 6 mice for each condition and timepoint are plotted. Statistical significance of the slopes after linear regression of the data is shown. F Overall survival of cancer patients treated primarily with radiotherapy at the Radiotherapy Service of the University Hospital Virgen Macarena considering if they were irradiated in the morning (blue line) or the afternoon (red line). Statistical significance was analyzed using Kaplan-Meier test. G Same as F but considering only prostate cancer patients. Statistical significance was analyzed using Kaplan-Meier test. H Same as F but considering only lung cancer patients. Statistical significance was analyzed using Kaplan-Meier test. I Same as F but considering only breast cancer patients. Statistical significance was analyzed using Kaplan-Meier test. J Same as F but considering only melanoma patients. Statistical significance was analyzed using Kaplan-Meier test. K Same as F but considering only glioma patients. Statistical significance was analyzed using Kaplan-Meier test. L Same as F but considering only head and neck cancer patients. Statistical significance was analyzed using Kaplan-Meier test. M Schematic representation of CRY1-mediated regulation of DNA end resection regarding CRY1 levels, represented for the circular arrow at the center of the image. (1) When CRY1 is low, CtIP and CCAR2 are recruited to DSBs (ii). However, CCAR2 cannot be maintained into chromatin, releasing CtIP and promoting maximum resection (iii). (3) On the contrary, when CRY1 peaks, it forms a complex with CCAR2. Upon DSB formation (i), all three proteins are recruited to damaged chromatin, where CRY1 is phosphorylated by DNA-PK (ii). This locks CRY1 and, consequently, CCAR2 on chromatin, hampering CtIP activity (iii). During the rest of the cycle (2 and 4), when CRY1 levels fluctuate, an intermediate situation ensues. I. e. some breaks will be promptly resected ((iii) left) and some will not ((iii) right), depending on the levels of CRY1.