Defining cell-matrix interactions in controlling immune cell function in cancer

Glucocorticoids (Gc) are the most potent anti-inflammatory agents known. After more than 50 years clinical use, synthetic Gcs remain the gold standard, and in many cases represent the first line treatment for a range of inflammatory diseases including asthma and rheumatoid arthritis, and are frequently prescribed to cancer patients as part of their therapy. Despite their wide application, clinical utility is limited, as an individual patients' sensitivity to Gc varies, and can diminish over time. This represents a particular problem as many serious diseases - cancer, cardiovascular, diabetes - have an inflammatory component. Gc mediate their cellular effects through binding and activating the glucocorticoid receptor (GR), a ligand activated transcription factor and member of the nuclear receptor superfamily. Unliganded GR is held in the cytoplasm, and upon engaging ligand, undergoes a conformational change, and then translocates into the nucleus. Once in the nucleus, GR regulates expression of inflammatory and cell fate genes by binding to DNA directly, or by tethering to other DNA bound transcription factors such as NF-kB and modulating their function. Recent studies have shown that cell-matrix interactions can influence gene expression and cell function. This is likely due to the combination of several cellular effects including altered subcellular trafficking of proteins, activation of intracellular signalling pathways and reorganisation of nuclear architecture. Our recent evidence in lung cancer cells indicates that changes to cell-matrix interactions disrupts GR/NF-kB crosstalk (the two major transcription factors that control immunity), suggesting that changes in cell-matrix interactions might also alter anti-inflammatory transcriptional responses.

The project will define in detail, how the cellular microenvironment modifies crosstalk between GR and NFkB and the consequences to immune signaling in cancer. We will first complete comprehensive bioinformatics analysis using next generation sequencing data (samples from patients with lung, liver, breast and brain cancer, stratified by age from the Cancer Genome Atlas, TGCA) to define a panel of cancer regulated extracellular matrix components to experimentally test in our study. We will test the effect of these matrix components in different ratios using relevant cancer and immune cell lines and primary human cells under baseline conditions and after stimulation using cytokine cocktails, cytotoxic drugs and DNA damaging agents. We will extend this analysis to determine the effect of cell-matrix interactions on cancer and immune intercellular communication using in vitro co-culture models. Finally, we will confirm these findings in vivo using a transgenic zebrafish (wt and GR null) in models of inflammation and cancer. This permits real-time tracking of immune cell infiltration and at sites of tumours and inflammation in whole organisms. Through this we will gain a better understanding of how the microenvironment controls immunity, and how these important anti-inflammatory drugs work in vivo. Training in all aspects of the project will be provided including advanced bioinformatics; in vitro cell culture models; immunofluorescent microscopy; immunoblotting; ELISA; PCR; in vivo models of inflammation/cancer. These broad skillsets provide an excellent training opportunity for individuals hoping to pursue a research career in fields related to cancer biology, inflammatory disease, or those with an inflammatory component such as cardiovascular disease.