A study of keratinocyte differentiation and adhesion in vitro

Owens, Dewi W. (1997) A study of keratinocyte differentiation and adhesion in vitro. PhD thesis, University of Glasgow.

Abstract

In this study, I used the serum-free MCDB 153 culture system to investigate calcium-induced keratinocyte differentiation.

Treating normal human keratinocytes with high extracellular calcium concentrations (1mM) increased the proportion of cells expressing differentiation-specific proteins. I showed that this was not caused by calcium-induced cell-cycle arrest, nor was it a consequence of stratification. However, the expression of differentiation-specific proteins was preceded by the formation of cadherin-mediated cell-cell adhesions.

The likely importance of the cadherin-mediated adhesions in initiation the differentiation program was confirmed in two ways. Firstly, clustering cell-surface E-cadherin in low extracellular calcium using monoclonal antibodies increased the proportion of keratinocytes expressing differentiation-specific proteins. Secondly, suppressing the formation of cadherin-mediated cell-cell adhesions using synthetic peptide analogous to the cadherin recognition domain attenuated the calcium-induced expression of differentiation-specific proteins. These data are consistent with a role for the cadherin-mediated cell-cell adhesions in initiating the keratinocyte differentiation program in response to calcium in vitro.

A second aspect of this project involved an investigation of the role played by the Src-family of protein tyrosine kinases at calcium-induced cadherin-mediated adherens junctions. The ubiquitously expressed members of this family, c-Src, Fyn and c-Yes were localised to the cadherin-mediated adhesions formed in response to high extracellular calcium. Treating adherent keratinocytes maintained in low extracellular calcium with a specific Src kinase inhibitor, PD162531, induced the assembly of cadherin-mediated cell-cell adhesions leading to the formation of contiguous groups of cells similar to those seen in response to high extracellular calcium.

The data presented are consistent with a role for the Src kinases in regulating adherens junction turnover but do not exclude a role also in modulating aspects of differentiation.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer)
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Supervisor's Name: Frame, Margaret and Parkinson, Keith
• Date of Award: 1997
• Depositing User: Mrs Marie Cairney
• Unique ID: glathesis:1997-1099
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 01 Sep 2009
• Last Modified: 10 Dec 2012 13:33
• URI: https://theses.gla.ac.uk/id/eprint/1099