Article
Ubiquitin C-terminal hydrolase L1 is downregulated in tumours of the central nervous system
Gehemmte Expression von Ubiquitin C-Terminal Hydrolase L1 in Tumoren des zentralen Nervensystems
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Authors
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Saskia Kuhl
- University Hospital Cologne, University of Cologne, Neurosurgery, Köln, Deutschland
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Sarah Stegmann
- University Hospital Cologne, University of Cologne, Neurosurgery, Köln, Deutschland
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Roland Goldbrunner
- University Hospital Cologne, University of Cologne, Neurosurgery, Köln, Deutschland
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Marco Timmer
- University Hospital Cologne, University of Cologne, Neurosurgery, Köln, Deutschland
| Published: | June 4, 2021 |
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Outline
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Objective: Ubiquitin C-terminal hydrolase L1 (UCHL1) is a neuron specific deubiquitinating enzyme. It hydrolyses small polypeptides from Ubiquitin, a small molecule regulating protein degradation by the Ubiquitin Proteasom System. Mutations in UCHL1 are associated with neurodegenerative diseases caused by protein accumulation. In tumours, UCHL1 has been controversially discussed. While its expression is increased in several cancer types like adenocarcinoma or breast cancer it is downregulated in melanoma and colorectal cancer. In meningiomas decreased UCHL1 expression is corelated with malignancy and promotor methylation. Paediatric glioma cell lines showed an elevated expression. Since there is not much known about UCHL1 in brain tumours, we aimed to analyse UCHL1 expression and promoter methylation in tumours of the central nervous system.
Methods: Tumour was obtained during neurosurgery and shock frozen in liquid nitrogen. Regarding WHO classification, meningioma grade I, II and III and glioma grade II and III, secondary- (sGBM) and primary glioblastoma (pGBM) before and after recurrence were grouped. Transcription rate was measured via real-time PCR. Amplification products were detected with SYBR Green and results normalized by ß-Actin. Protein expression was determined with Western Blot. UCHL1 was detected with a primary UCHL1 antibody and visualized with a HRP-conjugated secondary antibody. Samples were measured in triplets. Statistical analysis was done with Kruskal-Wallis and Mann-Whitney- U for non-parametric and one way ANOVA and Tukey’s test for normally distributed data. For immunofluorescence staining cryo slices were stained with a primary UCHL1 and a Cy3-conjugated secondary antibody. Nuclei were stained with DAPI.
Results: Transcription of UCHL1 is significantly decreased in meningioma (7.64±5.67 vs. 0.98±0.91, p<0.0001) and glioma (7.64±5.67 vs. 1.06±0.68, p=0.0004) compared to peritumoral tissue. Western Blot confirmed PCR results with a downregulation in meningioma (1.97±0.49 vs. 0.19±0.22, p<0.0001) and glioma (1.35±0.12 vs. 0.49±0.35, p<0.0001) compared to control tissue. Results could be confirmed with immunostaining.
Conclusion: UCHL1 is significantly downregulated in meningioma and glioma compared to peritumoral tissue. Since the protein expression is brain specific, UCHL1 could be a possible therapeutic target for treatment of tumours of the central nervous system.
