Article
Expression level of Ubiquitin C-terminal hydrolase L1 in tumours of the central nervous system correlates with the amount of present neurons
Expressionsrate von Ubiquitin C-Terminal Hydrolase L1 in Tumoren des zentralen Nervensystems korreliert mit der Anzahl an Neuronen im Tumorgewebe
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Authors
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Saskia Kuhl
- Universitätsklinikum Köln, Klinik für Neurochirurgie, Köln, Deutschland
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Roland Goldbrunner
- Universitätsklinikum Köln, Klinik für Neurochirurgie, Köln, Deutschland
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Marco Timmer
- Universitätsklinikum Köln, Klinik für Neurochirurgie, Köln, Deutschland
| Published: | May 25, 2022 |
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Outline
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Objective: UCHL1 is a neuron specific deubiquitinating enzyme, which recycles Ubiquitin, a small molecule regulating protein degradation by the Ubiquitin Proteasome System. Mutations in UCHL1 are associated with neurodegenerative diseases caused by protein accumulation. In tumours expression of UCHL1is both, up-regulated in several cancer types like adenocarcinoma or breast cancer or down-regulated like melanoma or colorectal cancer. In meningioma, decreased UCHL1 expression correlates with higher malignancy and increased promotor methylation. In previous investigations, we showed a significant downregulation of UCHL1 in glioma and meningioma. Since UCHL1 is neuron specific, we now wanted to examine if lower expression is due to the amount of neurons or promoter methylation.
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 quantified using real-time qPCR and protein level using western blot. For co-staining of UCHL1 and neurons, same samples as for quantification were used. Cryo slices were cut 10µm thick and fixed with 4% PFA. Primary UCHL1 antibody was visualized with an alexa-flour-488 conjugated secondary antibody. Visualizing of neurons was done with specific Tubulin-ß-III and alexa-flour-555 conjugated secondary antibody. Images were taken with a Zeiss Apotome microscope at 20x magnification. Methylation status was checked with a kit and primer designed by Qiagen.
Results: Transcription of UCHL1 is significantly decreased in meningioma (p<0.0001) and glioma (p=0.0004) compared to peritumoral tissue. Western Blot confirmed PCR results with a downregulation in meningioma (p<0.0001) and glioma (p<0.0001) compared to control tissue. Co-staining showed a correlation between expression level of UCHL1 in brain tumour and the amount of present neurons in tumour tissue.
Conclusion: UCHL1 is significantly downregulated in meningioma and glioma compared to peritumoral tissue. Since UCHL1 is neuron specific, we co-stained UCHL1 and another neuron specific marker to determine if expression of UCHL1 is related to presence of neurons. Indeed, the expression level of UCHL1 seems to correlate with the amount of neurons present in tumour tissue.
