Does apoptosis of cancer-associated fibroblasts contribute to tumour progression?

Background
We have recently shown that cancer-associated fibroblasts (CAF), the major cellular component of the tumour microenvironment, play a key role in cancer progression and resistance to therapy (e.g. Kabir TD et al, Aging, 2016). CAF represent an attractive drug target due to their genetic stability that, in contrast to cancer cells, makes them unlikely to develop resistance to drugs. The development of drugs targeting CAF is hampered by a lack of understanding of their basic biology. In particular, very little is known of the role of apoptosis (programmed cell death) in regulating CAF abundance and function. In vivo, tissue homeostasis is achieved by a balance of proliferation and apoptosis. In addition to eliminating cells, apoptosis may also influence the behaviour of surrounding cells through the release of apoptotic bodies (a subset of extracellular vesicles) and other soluble factors. In cancer, it is well known that apoptosis of cancer cells can, counter-intuitively, promote tumour growth by stimulating proliferation of surrounding cells and modulating immune responses. Little is known, however, of the influence of CAF apoptosis, whether occurring naturally or in response to treatment, on cancer cell behaviour or immune responses.

Hypothesis
The aim of this completely novel project is to test the hypothesis that drug-induced apoptosis of CAF influences the behaviour of cancer and/or immune cells due to the generation of apoptotic bodies and other factors.

Methods
Apoptosis will be induced in primary human fibroblasts isolated from healthy controls and oral cancer patients using a variety of pro-apoptotic agents. Successful induction of apoptosis will be assessed using a combination of methods including a caspase-3 cleavage assay. Conditioned medium will be collected from apoptotic cultures and used in indirect co-culture models to assess effects on i) cancer cell proliferation (MTT assay) and migration (Transwell assay) and ii) immune cell recruitment (Transwell assay) and phenotype (qPCR and flow cytometry). In parallel, the abundance and nature of apoptotic extracellular vesicles (apoEVs) in the supernatants of apoptotic fibroblasts will be assessed by Zetaview analysis. ApoEVs will be isolated from supernatants by size exclusion chromatography and high-speed centrifugation and their effects on cancer cell and monocyte behaviour assessed using the assays described above.

This project will generate novel information regarding the role of fibroblast apoptosis in cancer, and may inform future therapeutic strategies targeting the tumour microenvironment.

You will join a group in which PhD students are key members and contribute (often as first author) to many of our publications. You will have access to excellent facilities, and collaborations with both academic researchers and industrial partners across the world. Many of our PhD students have spent time working abroad or in industry as part of their projects, and opportunities for this will be explored.