Daniel Zicha

Identification of proteins underlying tumour progression towards metastasis

This is a PhD studentship involves a collaborative project between Dr Daniel Zicha (Light Microscopy Laboratory, London Research Institute), Prof. Julian Downward (Signal Transduction Laboratory, London Research Institute) and Dr Olivier E Pardo (CeRN Laboratory, Imperial College London)

The successful candidate should have a background in biology and/or imaging.

Project description:
In order to study mechanisms of metastasis, we have been using metastasising sarcoma cell populations derived from Lewis inbred rats by spontaneous transformation followed by tumour progression. Using light microscopy with cells in tissue culture, we described quantitatively systematic changes in morphology, motility (Pokorna et al, 1994) and chemotaxis (Zicha and Dunn, 1995).

These changes accompanied the tumour progression resulting in the highly metastatic phenotype. Recently, we have analysed the associated changes in gene expression using Affymetrix microarrays (Cavanna et al, 2007).

The proposed project will involve imaging the changes in cellular behaviour resulting from both induced over-expression and suppression of a selected set of genes that are significantly changed in the metastasising cell populations. The experimental over expression and suppression will be achieved by transfection using constructs and by RNAi technique respectively.

One candidate protein this project will focus on is CASK where we already have explored its potential functional consequences in isolation without finding any obvious phenotype in the rat sarcoma cells. Our particular interest in CASK is supported by our microarray data where its expression was significantly suppressed in the metastasising cells and also by it being a potential interactor with protein 4.1B, which was shown to be a likely metastasis suppressor.

In addition, CASK was identified as a modulator of cell migration in a screen performed on human non-small cell lung carcinoma cells A549 by our collaborators (Pardo et al, 2003; Pardo et al, 2006).

Initially, fixed cells will be evaluated automatically in order to quantify morphological changes resulting from experimental treatment using the high throughput imaging system Discovery 1 (Molecular Devices). In the following stage, suitable experimental situations identified with fixed cells will be analysed dynamically with live cell imaging using time-lapse microscopy with biofluorescent proteins and specialised techniques such as Fluorescence Localisation After Photobleaching (Zicha et al, 2003).

In the long term, the relevance of our findings to a clinical setting will be investigated using clinical samples from various tumour origins in collaboration with Olivier Pardo (CeRN Laboratory, Imperial College). This project might lead to the identification of novel therapeutic targets for cancer that would prevent the appearance of tumour metastasis, a main cause of death in patients suffering from this disease.

References

Cavanna T, et al. Evidence for protein 4.1B acting as a metastasis suppressor. J Cell Sci 2007; 120: 606-616.

Pardo OE, et al. Fibroblast growth factor 2-mediated translational control of IAPs blocks mitochondrial release of Smac/DIABLO and apoptosis in small cell lung cancer cells. Mol Cell Biol 2003; 23: 7600-7610.

Pardo OE, et al. FGF-2 protects small cell lung cancer cells from apoptosis through a complex involving PKCε, B-Raf and S6K2. EMBO J 2006; 25: 3078-3088.

Zicha D, et al. Rapid actin transport during cell protrusion. Science 2003; 300: 142-145.