Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy
Background: Radiotherapy constitutes an important therapeutic option for prostate cancer. However, prostate cancer cells often acquire resistance during cancer progression, limiting the cytotoxic effects of radiotherapy. Among factors regulating sensitivity to radiotherapy are members of the Bcl-2 p...
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MDPI AG
2023-04-01
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| Series: | Cancers |
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| Online Access: | https://www.mdpi.com/2072-6694/15/9/2496 |
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| author | Sophia A. Hogh-Binder Diana Klein Frederik Wolfsperger Stephan M. Huber Jörg Hennenlotter Arnulf Stenzl Justine Rudner |
| author_facet | Sophia A. Hogh-Binder Diana Klein Frederik Wolfsperger Stephan M. Huber Jörg Hennenlotter Arnulf Stenzl Justine Rudner |
| author_sort | Sophia A. Hogh-Binder |
| collection | DOAJ |
| description | Background: Radiotherapy constitutes an important therapeutic option for prostate cancer. However, prostate cancer cells often acquire resistance during cancer progression, limiting the cytotoxic effects of radiotherapy. Among factors regulating sensitivity to radiotherapy are members of the Bcl-2 protein family, known to regulate apoptosis at the mitochondrial level. Here, we analyzed the role of anti-apoptotic Mcl-1 and USP9x, a deubiquitinase stabilizing Mcl-1 protein levels, in prostate cancer progression and response to radiotherapy. Methods: Changes in Mcl-1 and USP9x levels during prostate cancer progression were determined by immunohistochemistry. Neutralization of Mcl-1 and USP9x was achieved by siRNA-mediated knockdown. We analyzed Mcl-1 stability after translational inhibition by cycloheximide. Cell death was determined by flow cytometry using an exclusion assay of mitochondrial membrane potential-sensitive dye. Changes in the clonogenic potential were examined by colony formation assay. Results: Protein levels of Mcl-1 and USP9x increased during prostate cancer progression, and high protein levels correlated with advanced prostate cancer stages. The stability of Mcl-1 reflected Mcl-1 protein levels in LNCaP and PC3 prostate cancer cells. Moreover, radiotherapy itself affected Mcl-1 protein turnover in prostate cancer cells. Particularly in LNCaP cells, the knockdown of USP9x expression reduced Mcl-1 protein levels and increased sensitivity to radiotherapy. Conclusion: Posttranslational regulation of protein stability was often responsible for high protein levels of Mcl-1. Moreover, we demonstrated that deubiquitinase USP9x as a factor regulating Mcl-1 levels in prostate cancer cells, thus limiting cytotoxic response to radiotherapy. |
| first_indexed | 2024-03-11T04:22:23Z |
| format | Article |
| id | doaj.art-8f9dcd346ebc4fa7a928783dcde75dd5 |
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| issn | 2072-6694 |
| language | English |
| last_indexed | 2024-03-11T04:22:23Z |
| publishDate | 2023-04-01 |
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| record_format | Article |
| series | Cancers |
| spelling | doaj.art-8f9dcd346ebc4fa7a928783dcde75dd52023-11-17T22:40:30ZengMDPI AGCancers2072-66942023-04-01159249610.3390/cancers15092496Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to RadiotherapySophia A. Hogh-Binder0Diana Klein1Frederik Wolfsperger2Stephan M. Huber3Jörg Hennenlotter4Arnulf Stenzl5Justine Rudner6Department of Radiation Oncology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, GermanyInstitute for Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Virchowstr. 173, 45147 Essen, GermanyDepartment of Radiation Oncology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, GermanyDepartment of Radiation Oncology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, GermanyDepartment of Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, GermanyDepartment of Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, GermanyInstitute for Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Virchowstr. 173, 45147 Essen, GermanyBackground: Radiotherapy constitutes an important therapeutic option for prostate cancer. However, prostate cancer cells often acquire resistance during cancer progression, limiting the cytotoxic effects of radiotherapy. Among factors regulating sensitivity to radiotherapy are members of the Bcl-2 protein family, known to regulate apoptosis at the mitochondrial level. Here, we analyzed the role of anti-apoptotic Mcl-1 and USP9x, a deubiquitinase stabilizing Mcl-1 protein levels, in prostate cancer progression and response to radiotherapy. Methods: Changes in Mcl-1 and USP9x levels during prostate cancer progression were determined by immunohistochemistry. Neutralization of Mcl-1 and USP9x was achieved by siRNA-mediated knockdown. We analyzed Mcl-1 stability after translational inhibition by cycloheximide. Cell death was determined by flow cytometry using an exclusion assay of mitochondrial membrane potential-sensitive dye. Changes in the clonogenic potential were examined by colony formation assay. Results: Protein levels of Mcl-1 and USP9x increased during prostate cancer progression, and high protein levels correlated with advanced prostate cancer stages. The stability of Mcl-1 reflected Mcl-1 protein levels in LNCaP and PC3 prostate cancer cells. Moreover, radiotherapy itself affected Mcl-1 protein turnover in prostate cancer cells. Particularly in LNCaP cells, the knockdown of USP9x expression reduced Mcl-1 protein levels and increased sensitivity to radiotherapy. Conclusion: Posttranslational regulation of protein stability was often responsible for high protein levels of Mcl-1. Moreover, we demonstrated that deubiquitinase USP9x as a factor regulating Mcl-1 levels in prostate cancer cells, thus limiting cytotoxic response to radiotherapy.https://www.mdpi.com/2072-6694/15/9/2496prostate cancerradiotherapyMcl-1protein stabilityubiquitylationUSP9x |
| spellingShingle | Sophia A. Hogh-Binder Diana Klein Frederik Wolfsperger Stephan M. Huber Jörg Hennenlotter Arnulf Stenzl Justine Rudner Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy Cancers prostate cancer radiotherapy Mcl-1 protein stability ubiquitylation USP9x |
| title | Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy |
| title_full | Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy |
| title_fullStr | Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy |
| title_full_unstemmed | Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy |
| title_short | Protein Levels of Anti-Apoptotic Mcl-1 and the Deubiquitinase USP9x Are Cooperatively Upregulated during Prostate Cancer Progression and Limit Response of Prostate Cancer Cells to Radiotherapy |
| title_sort | protein levels of anti apoptotic mcl 1 and the deubiquitinase usp9x are cooperatively upregulated during prostate cancer progression and limit response of prostate cancer cells to radiotherapy |
| topic | prostate cancer radiotherapy Mcl-1 protein stability ubiquitylation USP9x |
| url | https://www.mdpi.com/2072-6694/15/9/2496 |
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