PhD in Cancer - Invasion and Metastasis Group
Job No:
G85
Location:
Darlinghurst, Sydney
Supervisor: Dr Paul Timpson
Background: Cancer invasion and metastasis occur in a complex 3D-environment, with reciprocal feedback from the surrounding host tissue and stroma governing cancer cell behaviour. Understanding this behaviour in an intact host setting allows us to examine, in a physiological context, the aberrant regulation of critical events that lead to dissemination and spread of the primary tumour. Intravital (in vivo) imaging is providing new insights on how cells behave in their native microenvironment in real-time, thereby improving our understanding of disease progression (1).
Our group specialises in applying state-of-the-art imaging technology and 3D modelling to assess the spread of cancer in living tissue (2-4). Two PhD projects are available in our laboratory using novel fluorescent biosensors to monitor cancer cell response to anti-invasive drug targeting in live tumours. Both projects involve cutting-edge training in 3D culture of cancer cells with associated stromal tissue engineering and involve molecular intervention with regards to controlling extracellular matrix strength and stiffness (a key feature known to drive the aggressive nature of cancer and its response to current therapeutics (5)). Response of tumour cells to drug targeting in relation to their proximity to blood vasculature (imaged using quantum dots) will also feature heavily in each project.
Each project will involve the use of novel cre-inducible mouse models engineered to uncouple the metastatic process into key stages, to identify critical steps in the metastatic cascade that are aberrantly regulated by candidate genes previously identified in our screen for drivers of invasion. Currently unavailable elsewhere, these models permit real-time, intravital imaging, ranging from whole body tumour progression to single-cell invasion events, and will help us to understand how (i) tumour cell dissociation (E-cadherin-GFP; FRAP model), (ii) invasion (Rac/RhoGTPase FRET reporter models) or (iii) cell growth/survival (GFP model) are controlled and how this is linked to the development of metastasis in the native tumour tissue microenvironment.
New approaches to a complex problem: Two sub-cellular applications currently in use in collaboration with pharmaceutical industry will form the basis of each project:
Project 1: In vivo FRAP: E-cadherin-based cell-cell contacts are prominent sites of remodeling during early stages of epithelial to mesenchymal transition (EMT). The deregulation of E-cadherin-based adhesions leads to the collapse of normal epithelial architecture that precedes the initial spread of tumours from their primary site and can therefore serve as an early molecular marker of invasion. We recently established the first application of Fluorescence Recovery After Photobleaching (FRAP) in live tumours to examine and predict E-cadherin cell-cell junction turnover during early stages of cancer dissemination. Importantly, we have now generated the world’s first E-cadherin-GFP FRAP mouse and will use this pre-clinical model to assess the effects of therapeutic intervention on E-cadherin dynamics using clinically approved anti-invasive drug therapy, and investigate whether candidate molecules from our screen alter E-cadherin dynamics to drive early tumour invasion (3).
Project 2: In vivo FRET: Co-ordinated regulation of RhoGTPases is known to control actin-mediated cell movement that is central to tumour cell invasion. Recently, we used Fluorescence Resonance Energy Transfer (FRET), for the first time, at the sub-cellular level in vivo, to examine RhoA activity during invasion in live tumours (4). Here, we identified at high resolution a small yet important pool of active RhoA at the poles of invading cells, not observed in vitro, that correlates with invasion in live tumours. Expansion of this work led to the first use of FRET to monitor the activity of RhoA at a sub-cellular, rather than global level, upon therapeutic intervention. As above, we have now generated a fluorescent RhoA-FRET mouse and will use this pre-clinical model to examine whether candidate molecules from our screen/drug targeting alter actin-mediated cell movement and invasion in live tissue.
Refs
(1) Timpson et al Journal of cell Science 2011 Sep 1;124(Pt 17):2877-90.
(2) Morton et al Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):246-51.
(3) Serrels et al Cancer Research 2009 Apr 1;69(7):2714-9.
(4) Timpson et al Cancer Res 2011 Feb 1;71(3):747-57.
(5) Samuel et al Cancer Cell 2011 Jun 14;19(6):776-91.