Project Details

Focal adhesion kinase (FAK) is a ubiquitously expressed non-receptor protein tyrosine kinase that localizes to cell surface protein complexes called focal adhesions (FAs), where the cytoskeletal platform interacts with proteins of the extracellular matrix. The major effects of FAK activation are increased cell migration, invasion, survival, proliferation, and angiogenesis. FAK appears to be a pivotal pathway in oncogenesis and recent phase 1 data is highly suggestive that FAK inhibition is effective in a number of tumour types with limited therapeutic options: melanoma, mesothelioma and possible high grade gliomas. The importance of FAK signalling in these tumours types may derive from the loss of activity of Merlin, the NF2 tumour suppressor gene product.

Merlin is known to be abnormal in many mesotheliomas although there is current little systematic information in melanoma or gliomas.

The proposed research project aims to better determine the therapeutic implications of FAK and NF2 biology in cancer (particularly melanoma, mesothelioma and gliomas) by:

1.Determining the frequency of FAK activation and loss of Merlin using established microarrays of patient tumour samples of melanoma, mesothelioma and gliomas.

2.Examine the utility of FAK and Merlin as predictive or prognostic biomarkers in cancer therapy

3.Examine the effects of a potent, specific small molecule inhibitor of FAK in cancer cells using established in vitro and in vivo assays for cancer stem cells, proliferation, apoptosis, migration, invasion, survival, proliferation, and angiogenesis.

References

Gan, H.K. and Siu, L. (2009). “Focal Adhesion Kinase as a Therapeutic Target in Cancer.” American Society of Clinical Oncology Education Handbook p130-136

Houshmandi, S. S., R. J. Emnett, et al. (2009). "The neurofibromatosis 2 protein, merlin, regulates glial cell growth in an ErbB2- and Src-dependent manner." Molecular and Cellular Biology 29(6): 1472-1486.

Poulikakos, P. I., G. H. Xiao, et al. (2006). "Re-expression of the tumor suppressor NF2/merlin inhibits invasiveness in mesothelioma cells and negatively regulates FAK." Oncogene 25(44): 5960-5968.

Return to Top

Project Details

Epithelial-to-mesenchymal transition (EMT) is a reversible complex cellular program that allows less aggressive, non-motile epithelial cells to acquire motile and more fibroblast-like, mesenchymal characteristics. EMT process critical for embryonic development is re-actived during adult cancer progression.

The main focus of this project will be to investigate whether EMT facilitates melanoma progression by contributing to cellular heterogeneity, metastatic competance and developing drug-resistance.

The objective of this study will be to identify molecular elicitors, novel markers and signalling pathways regulating EMT in melanoma. Furthermore, particular emphasis will be on identifying novel therapeutic targets to inhibit or reverse EMT in melanoma which may result in better treatment options.

Return to Top

Project Details

Cancer and stem cells share a number of biological characteristics such as chemoresistance the ability to migrate, proliferate indefinitely and repopulate tissues. Resistance to treatment and metastasis have been attributed to stem-like behavior. This has prompted investigation of ‘cancer stem-cells’ as potentially important therapeutic targets. Such cells might represent a minority poulation within a cancer and so escape therapeutic approaches that target the bulk of the tumour.

In melanoma the identification of melanoma stem cells relied on the utilization of cancer-stem cell markers identified in other cancers and there is controversy regarding the existence and characteristics of melanoma stem cells. The plasticity of cell populations in melanoma has confounded this since it is now clear that these characteristics are not stable.

In order to create stable stem-like populations for further study we will use the same technique that others have employed to create stem cells from somatic cells. This involves the transfer of stem-cell-defining genes (Sox2, Oct3/4, nanog and Klf4). By inserting these genes into melanoma cell lines, we anticipate that stable stem-like lines can be created.

In this project we will endeavour to use established stem cell techniques to artifically create melanoma stem cells, characterize them and translate the findings into patient tumours to prove the concept of melanoma stem cells. We will undertake an in-depth analysis of these cells on the level of gene-expression using microarray technology, immuno-histochemistry (IHC), qPCR and western-blotting followed by a range of functional in-vitro and in-vivo assays established in our laboratory.

We will subsequently compare the obtained results against tumour samples in hope of discovering the elusive melanoma stem cell and therefore open new possibilities for targeted therapies.

References

Gedye, C., Quirk, J., Browning, J., Svobodova, S., John, T., Sluka, P., Dunbar, P.R., Corbeil, D., Cebon, J., and Davis, I.D., Cancer/testis antigens can be immunological targets in clonogenic CD133(+) melanoma cells. Cancer Immunol Immunother, 2009.

Cebon J, Geyde C, John T, and Davis ID. Immunotherapy of advanced or metastatic melanoma. Clinical Advances in Hematology and Oncology, 5:994-1006,2007

Return to Top

Project Details

While the development of combination chemotherapy regimens and the approval of a number of biological agents has resulted in significantly improved response rates and prolonged survival in patients with metastatic colon cancer, the vast majority of patients eventually develop resistance to the these agents. As a result, 5 year survival rates for patients with inoperable metastatic colon cancer remains below 20%. Identification of the escape pathways induced by tumour cells in response to continued drug exposure may provide insight into alternative treatment strategies. Through continuous culture to increasing doses of chemotherapeutic drugs in vitro, we have generated colon cancer cell lines with acquired resistance to the major agents used in the treatment of colon cancer – 5FU, irinotecan and oxaliplatin. The advent of whole genome, transcriptome and proteome profiling technologies now offers an unprecedented opportunity to characterize these cell lines and delineate the pathways involved in acquired resistance. This PhD project will involve the continued development of these cell lines, their characterization using cutting edge technologies such as Next-generation sequencing, and the testing of rational treatment strategies to overcome the acquired resistance.

Return to Top

Project Details

Our laboratory program has developed an antibody specific to the Lewis-y (Ley) protein antigen (hu3S193) and conducted first in man clinical trials with this immunotherapeutic in cancer patients: The Ley antigen is found in 30-50% of breast cancers and over 70% of all epithelial cancers [1]. In laboratory assays, the hu3S193 antibody is able to recognize and kill cells which have the Ley antigen, a key feature of anti-cancer treatments [2, 3]. Hu3S193 has potent immune effector function, and has been demonstrated to efficiently target cancer cells in mouse models, and in human clinical trials [1, 4]. This research project aims to exploit the targeting properties of hu3S193, and identify potent regulators of immune system activation for improved tumour cell killing. Molecular biology techniques will be used to design and engineer novel humanised IgG constructs with improved complement and NK cell mediated immune effector function for tumour cell killing. Structural modelling studies involving Fc-C1q binding, and FcgRIII and FcgRIIb interactions with Fc, will be used to derive novel constructs, which will be characterised in in-vitro and in-vivo systems [5]. Further studies involving Fc-FcRn interactions and modulation of pharmacokinetics of recombinant humanised IgG will also be explored. This will allow the identification of potent modified forms of hu3S193 that can be extended into clinical trials.

References

1.Scott, A.M., et al., Construction, production, and characterization of humanized anti-Lewis Y monoclonal antibody 3S193 for targeted immunotherapy of solid tumors. Cancer Res, 2000. 60(12): p. 3254-61.

2.Clarke, K., et al., In vivo biodistribution of a humanized anti-Lewis Y monoclonal antibody (hu3S193) in MCF-7 xenografted BALB/c nude mice. Cancer Res, 2000. 60(17): p. 4804-11.

3.Clarke, K., et al., Therapeutic efficacy of anti-Lewis(y) humanized 3S193 radioimmunotherapy in a breast cancer model: enhanced activity when combined with taxol chemotherapy. Clin Cancer Res, 2000. 6(9): p. 3621-8.

4.Scott, A.M., et al., A phase I biodistribution and pharmacokinetic trial of humanized monoclonal antibody Hu3s193 in patients with advanced epithelial cancers that express the Lewis-Y antigen. Clin Cancer Res, 2007. 13(11): p. 3286-92.

5.Ramsland, P.A., et al., Structural convergence of antibody binding of carbohydrate determinants in Lewis Y tumor antigens. J Mol Biol, 2004. 340(4): p. 809-18.

Return to Top

Project Details

STAT3 is one of the best studied molecules involved in oncogenic signalling and has been shown to have an essential role in malignant progression. Several proof-of-concept studies in cell-culture and animal models have demonstrated that constitutive STAT3 signalling promotes the growth and survival of tumour cells and induces tumour angiogenesis and suppresses antitumour immune responses (1, 2). Interestingly, STAT3 was shown in recent studies to be overactivated in 56-90% of colorectal carcinoma biopsies. Accordingly, STAT3 is a promising molecular target for novel cancer therapies in colorectal cancer. Small Interfering RNAs (siRNAs) are one of the newest and most powerful tools of biomedical research. This project will explore the role of STAT3 in colorectal cancer and investigate the effect of siRNA inhibition of STAT3 on growth and tumourigenicity of colorectal cancer cells. For the therapeutic development of these siRNAs, novel conjugate siRNAs that target STAT3 to tumour via a humanised monoclonal antibody (3) will be created and evaluated through in-vitro and in in-vivo models. The validation of STAT3 knockdown will be assessed in colon tumour models. Additional genes associated with colorectal cancer will also be studied with siRNA knockdown, and through immunoconjugate delivery systems. This approach aims to develop a new class of therapeutic agents for the treatment of colorectal cancer.

References

1.Yu H et al. 2004 The STATS of cancer – new molecular targets come of age. Nature Rev Cancer 4:97-105

2.Mulkeen AL, et al. 2006. Short interfering RNA-mediated gene silencing of vascular endothelial growth factor: effects on cellular proliferation in colon cancer cells. Arch Surg. 141:367-74

3.Scott AM, et al. 2007 A Phase I biodistribution and pharmacokinetic trial of humanized monoclonal antibody hu3S193 in patients with advanced epithelial cancers which express the Lewis-y antigen. Clin Cancer Res 13:3286-92

Return to Top