Universität zu Köln

Goranci-Buzhala, Gladiola (2020). Characterization of primary cilia in patient-derived glioma stem cells. PhD thesis, Universität zu Köln.

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Abstract

Primary cilia are highly conserved eukaryotic organelles that serve as a ‘’cellular antenna’’ for signaling functions. Dysfunctions or defects in primary cilia are associated with numerous human diseases. Typically, the mother centriole, transforms into a structure called basal body, which then templates the formation of the primary cilium. Abnormal cilia are implicated in cancer progressions such as in breast, pancreatic, brain, and prostate cancers. Glioblastoma multiforme (GBM) is one of the most frequent lethal primary brain tumors. GBM is characterized by extreme heterogeneity, rapid growth, and efficient invasion of neoplastic cells, called Glioblastoma Stem-like Cells (GSCs). GSCs represent a subpopulation of the cells that are resistant to treatment and are suspected to be driving forces for the disease recurrence. Until now, there is no effective treatment for GBM. The average median survival time of the patients from the initial diagnosis is 12-15 months. GBM cells appear to lose cilia, which can contribute to the malignant phenotype. However, the mechanism of suppressed ciliogenesis is not fully characterized yet. Thus, the aims of this thesis were (i) to understand the possible mechanisms that can suppress the ciliogenesis in GSCs, (ii) to investigate the pathways that could restore the ciliogenesis and, (iii) characterize GSCs after cilium induction. Primary cilium assembly and disassembly are a dynamic process, which is coupled with the cell cycle. At the onset of cilium disassembly, the Centrosomal-P4.1-associated protein (CPAP) provides a scaffold for the cilium-disassembly complex (CDC) proteins, including NDE1, OFD1, NEK2, and CPAP. These proteins are recruited to the ciliary base to ensure timely cilium disassembly and promote cell cycle progression. Hence, using multidisciplinary approaches, the current doctoral thesis investigated primary cilia dynamics in multiple patient-derived GSCs. The experiments revealed that elevated levels and recruitment of CDC components lead to suppressing of the ciliogenesis and an increase in the cell cycle progression. Moreover, depletion of different CDC proteins induced ciliogenesis in GSCs in which PDGFR-α level is elevated. Among the CDC proteins, NEK2 depletion induced the maximum frequencies of ciliation in GSCs. Furthermore, inducible overexpression of the catalytically inactive NEK2 in GSCs was sufficient to induce cilia irreversibly. Importantly, both functional, including transcriptomic analyzes, showed that cilium induction switched GSCs from self-renewal to differentiation state. Taken together, the current work provides evidence for a novel mechanism to induce ciliogenesis in patient-derived GSCs and suggests that the cilium induction can potentially serve as a new strategy to intervene in GSCs proliferation.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Goranci-Buzhala, Gladiola gladiolagoranci@hotmail.com UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-121580
Date:	22 September 2020
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	COPT.ZENTRUM
Subjects:	Natural sciences and mathematics Life sciences Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Primary cilia English Glioma English Stem cells English 3D human brain organoids English
Date of oral exam:	10 June 2020
Referee:	Name Academic Title Uhlirova, Mrika Prof. Dr. Schermer, Bernhard Prof. Dr. Gopalakrishnan, Jay Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/12158