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Functional Assessment of Kinesin-7 CENP-E in Spermatocytes Using In Vivo Inhibition, Immunofluorescence and Flow Cytometry
Published on: December 28, 2021
Increased expression and nuclear localization of the centrosomal kinase Nek2 in human testicular seminomas
Federica Barbagallo1, Maria P Paronetto, Renato Franco
1Department of Public Health and Cell Biology, University of Rome Tor Vergata, 00133 Rome, Italy.
Abstract:
Protein kinases that regulate the centrosome cycle are often aberrantly controlled in neoplastic cells. Changes in their expression or activity can lead to perturbations in centrosome duplication, potentially leading to chromosome segregation errors and aneuploidy. Testicular germ cell tumours (TGCTs) are characterized by amplification of centrosomes through unknown mechanisms. Herein, we report that Nek2, a centrosomal kinase required for centrosome disjunction and formation of the mitotic spindle, is up-regulated in human testicular seminomas as compared to control testes or other types of testicular germ cell tumours. In addition, Nek2 activity is also increased in human seminomas, as demonstrated by immunokinase assays. Analysis by immunohistochemistry indicated that Nek2 is prevalently localized in the nucleus of neoplastic cells of primary human seminomas. Such nuclear localization and the up-regulation of Nek2 protein were also observed in the Tcam-2 seminoma cell line. We demonstrate that nuclear localization of Nek2 is a feature of the more undifferentiated germ cells of mouse testis and correlates with expression of the stemness markers OCT4 and PLZF. These studies suggest that up-regulation of Nek2 is a frequent event in human seminomas and that this may participate in the onset or progression of neoplastic transformation through deregulation of centrosome duplication and/or nuclear events in germ cells.
Insights
Nek2 kinase is up-regulated in human testicular seminomas, potentially driving cancer development by affecting centrosome duplication and nuclear events in germ cells.
Area of Science:
- Cell Biology
- Cancer Biology
- Molecular Oncology
Background:
- Aberrant regulation of protein kinases controlling the centrosome cycle is common in neoplastic cells.
- Altered centrosome duplication can lead to chromosome segregation errors and aneuploidy.
- Testicular germ cell tumors (TGCTs) exhibit centrosome amplification via unknown mechanisms.
Purpose of the Study:
- To investigate the role of Nek2 kinase in human testicular seminomas.
- To determine if Nek2 expression and activity are altered in seminomas.
- To explore the subcellular localization and potential function of Nek2 in germ cell neoplasia.
Main Methods:
- Immunohistochemistry to assess Nek2 protein levels and localization in human seminoma samples and cell lines.
- Immunokinase assays to measure Nek2 activity.
- Analysis of Nek2 localization in mouse testis germ cells and correlation with stemness markers (OCT4, PLZF).
Main Results:
- Nek2 kinase is significantly up-regulated in human testicular seminomas compared to normal testes and other TGCTs.
- Increased Nek2 activity was observed in human seminomas.
- Nek2 predominantly localized to the nucleus in neoplastic cells of primary human seminomas and in the Tcam-2 cell line.
- Nuclear localization of Nek2 in mouse germ cells correlates with undifferentiated status and stemness markers OCT4 and PLZF.
Conclusions:
- Up-regulation of Nek2 is a frequent event in human seminomas.
- Altered Nek2 may contribute to neoplastic transformation in germ cells by deregulating centrosome duplication and nuclear events.
- Nuclear localization of Nek2 may be linked to germ cell stemness and early stages of tumorigenesis.
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