Endosomal cargoes in ovarian cancer invasion

  • Beverley Wilson

Student thesis: Phd


Endosomal recycling of cell-surface receptors is important for the regulation of cell migration and invasion in 3D environments. Rab GTPases control intracellular trafficking, with Rab4a and the Rab11-family being key regulators of endosomal recycling processes. Rab11a, through its effector Rab-coupling protein, and Rab25 (Rab11c) have been shown to control the recycling of the major fibronectin receptor α5β1 integrin to promote cytoskeletal reorganisation leading to cell invasion into fibronectin-rich 3D environments. Aberrant expression of Rab25 has been implicated in ovarian cancer progression, with upregulated expression in late-stage disease correlated with poor patient outcome. Improved understanding is needed of the molecular mechanisms which drive ovarian cancer metastasis. To better understand the impact of endosomal recycling on ovarian cancer cell migration an optimised BioID approach was used to identify Rab4a, Rab11a and Rab25 proximal proteins in an unbiased manner. Quantitative label-free proteomics using stringent statistical analysis identified tens of high-confidence proximal proteins for each Rab GTPase. These high-confidence Rab GTPase proximal proteins included a large range of known Rab GTPase regulators and effectors, cell surface proteins and trafficking machinery components. Proteins with previously unrecognised roles in endosomal recycling were also identified, and five candidate proteins were selected for further study into their functional roles in cell migration. Investigation of these candidate proteins revealed that three of them play novel functional roles in the promotion of ovarian cancer cell migration in 3D environments and co-localise with recycling endosomes. Firstly, CLINT1 was identified as a high-confidence proximal protein enriched towards Rab4a, which promotes the migration of cells which utilise Rab4a endosomal recycling processes to drive cell movement. Secondly, CRACR2A was identified as a high-confidence Rab11a and Rab25 proximal protein which has a general effect on 3D cell migration, possibly through the retrograde transport of endosomal cargoes. Finally, SH3BP5L was identified as a high-confidence proximal protein enriched towards Rab25 and likely drives Rab25-dependent 3D cell migration processes through its ability to activate Rab25 directly. Overall, this project has utilised an unbiased proteomic approach to identify and characterise candidate endosomal proteins with novel roles in 3D cell migration, providing fresh insight into the molecular mechanisms that underpin ovarian cancer cell migration. Further investigation of these candidates could lead to therapeutic advance and reduce ovarian cancer disease mortality.
Date of Award1 Aug 2020
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorSam Griffiths-Jones (Supervisor) & Patrick Caswell (Supervisor)


  • endosomal recycling
  • ovarian cancer
  • cell migration
  • cell invasion

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