en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: All To enhance the curative effect of radiotherapy, we established a radio-resistant cell line, CNE-2R from CNE-2, a radio-sensitive type of CNE, through repeated irradiation. The developed cell line provides a basis for further studies on the radio-resistance of CNE and the molecular mechanism of radiotherapy sensitization drugs. Materials and Methods: The CNE-2 cell line was selected and exposed repeatedly to high-dose X-ray intermittent irradiation (6 Gy/fraction for seven fractions and 20 Gy/fraction for three fractions). After the entire irradiation process, 20 Gy/time was administered to CNE irregularly. The cell growth curves of CNE-2 and CNE-2R were constructed based on MTT assays. Dose-survival curves were obtained through colony-forming tests and subjected to linear quadratic formulation matching. SF2 and correlation parameters of radiation biology were calculated. Changes in the cell cycle of CNE-2 and CNE-2R were also assessed by serum starvation. Results: The doubling time of CNE-2 was 2.4 days, which is 0.4 days shorter than that of CNE-2R, indicating the faster growth rate of CNE-2. In the dose-survival equation of the survival clone test, the sensitization ratio of CNE-2R was enhanced relative to that of CNE-2. After synchronization and desynchronization for 24 h, G1 was arrested in CNE-2R. In the S phase, which is insensitive to radiation, the ratio of G1 increased, hence altering the cell cycle. Conclusion: We have established a radio-resistant nasopharyngeal carcinoma cell line by repeated exposure to radiation which is relevant to changes in the cell cycle.</div> Cell cycle, cell growth curve, cell radiation biology parameter, nasopharyngeal carcinoma, radio-resistance. 47 55 http://ijrr.com/browse.php?a_code=A-10-1-757&slc_lang=en&sid=1 D. Zhu 7900319475328460013198 7900319475328460013198 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China M. Huang 7900319475328460013199 7900319475328460013199 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China M. Fang 7900319475328460013200 7900319475328460013200 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China A. Li 7900319475328460013201 7900319475328460013201 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China Z. Liu 7900319475328460013202 7900319475328460013202 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China M. Shao 7900319475328460013203 7900319475328460013203 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China Y. Liu 7900319475328460013204 7900319475328460013204 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China J. Yang 7900319475328460013205 7900319475328460013205 No School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China Q. Fan fanqinshimen@yahoo.com 7900319475328460013206 7900319475328460013206 Yes School of Traditional Chinese Medicine, Southern Medical University, Guangdong Guangzhou, 510515, China 2NanFang Hospital, Guangdong Guangzhou, 510515, China