Di Cao1, Tsz Kin Ng1, Yolanda W Y Yip1, Alvin L Young2, Chi Pui Pang1, Wai Kit Chu3, Vishal Jhanji4. 1. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong. 2. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. 3. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong. Electronic address: waikit@cuhk.edu.hk. 4. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. Electronic address: jhanjiv@upmc.edu.
Abstract
AIMS: To confirm that mouse double minute 2 (MDM2) could inhibit p53 activity in human pterygium. And to show the disruption of MDM2-p53 interaction could reactive the functions of p53 in pterygium. METHOD: Pterygium and corresponding conjunctiva tissues were collected for establishment of primary cell lines. Expression patterns of MDM2 and p53 were detected by immunofluorescence. Protein localization of p53 and MDM2, and transcriptional activity of p53 in both untreated and MDM2 antagonist (Nutlin) treated pterygium cells were quantified. RESULTS: In pterygium, p53 was highly expressed in cytoplasm and slightly expressed in the nuclei. MDM2 was localized in the nuclei. A p53 transcriptional regulated target gene, p21, was not expressed in pterygium tissues, suggesting the p53 transcriptional activity was not active in pterygium. After treatment with Nutlin, increased nuclear localization of p53 (4.05%-80.56%) was observed in pterygium cells along with increasing Nutlin dosages (from 0 to 50 μM, p < 0.001). The expression of p21 was increased after Nutlin treatments in pterygium cells (2.49 folds in 20 μM Nutlin treated cells compared to control treated cells, p = 0.012). CONCLUSION: We discovered a novel mechanism in pterygium whereby MDM2 suppresses p53 transcriptional activity despite abundant p53 in pterygium. Disruption of MDM2-p53 interaction by Nutlin could be a potential treatment for pterygium.
AIMS: To confirm that mouse double minute 2 (MDM2) could inhibit p53 activity in human pterygium. And to show the disruption of MDM2-p53 interaction could reactive the functions of p53 in pterygium. METHOD: Pterygium and corresponding conjunctiva tissues were collected for establishment of primary cell lines. Expression patterns of MDM2 and p53 were detected by immunofluorescence. Protein localization of p53 and MDM2, and transcriptional activity of p53 in both untreated and MDM2 antagonist (Nutlin) treated pterygium cells were quantified. RESULTS: In pterygium, p53 was highly expressed in cytoplasm and slightly expressed in the nuclei. MDM2 was localized in the nuclei. A p53 transcriptional regulated target gene, p21, was not expressed in pterygium tissues, suggesting the p53 transcriptional activity was not active in pterygium. After treatment with Nutlin, increased nuclear localization of p53 (4.05%-80.56%) was observed in pterygium cells along with increasing Nutlin dosages (from 0 to 50 μM, p < 0.001). The expression of p21 was increased after Nutlin treatments in pterygium cells (2.49 folds in 20 μM Nutlin treated cells compared to control treated cells, p = 0.012). CONCLUSION: We discovered a novel mechanism in pterygium whereby MDM2 suppresses p53 transcriptional activity despite abundant p53 in pterygium. Disruption of MDM2-p53 interaction by Nutlin could be a potential treatment for pterygium.
Authors: Sara I Van Acker; Bert Van den Bogerd; Michel Haagdorens; Vasiliki Siozopoulou; Sorcha Ní Dhubhghaill; Isabel Pintelon; Carina Koppen Journal: Cells Date: 2021-06-22 Impact factor: 6.600