MicroRNAs and stromal-epithelial cell signalling during carcinogenesis
Lead Research Organisation:
University of Leeds
Department Name: Unknown
Abstract
Alterations in the levels of certain proteins within a cell changes a normal epithelial cell into a malignant cancer cell. Similar changes also occur in the cells adjacent to these cancer cells - the stromal fibroblasts. These fibroblasts influence the behaviour of the cancer cells, and thereby influence cancer outcome.
MicroRNAs are molecules that control the amounts of certain proteins. The microRNAs within normal and cancer epithelial cells are different, and are responsible - in part - for the process of becoming a cancer. My hypothesis is that the microRNAs within fibroblast cells are different in normal tissue and cancer tissue. I propose to study the fibroblast microRNAs, and to examine their role in controlling the behaviour of cancers. This may eventually help in prediction of likely survival from individual cancers and in development of novel cancer treatments targeted against these pathways.
MicroRNAs are molecules that control the amounts of certain proteins. The microRNAs within normal and cancer epithelial cells are different, and are responsible - in part - for the process of becoming a cancer. My hypothesis is that the microRNAs within fibroblast cells are different in normal tissue and cancer tissue. I propose to study the fibroblast microRNAs, and to examine their role in controlling the behaviour of cancers. This may eventually help in prediction of likely survival from individual cancers and in development of novel cancer treatments targeted against these pathways.
Technical Summary
Background
During carcinogenesis, epithelial cells and adjacent stromal fibroblasts both exhibit changes in gene expression. Molecular pathways responsible for these changes are better researched and understood in epithelial cells than in fibroblasts, despite the fact that fibroblasts adjacent to carcinoma cells (carcinoma-associated fibroblasts, CAFs) have important influences on cancer behaviour. MicroRNAs are newly discovered regulators of gene expression, which have roles in the control of proliferation and apoptosis. Importantly, critical roles for microRNAs as tumour-suppressor genes and oncogenes have been identified in the epithelial cells of many cancers. Potential analogous roles for microRNAs within stromal fibroblasts during carcinogenesis remain un-explored.
Aims
I will elucidate microRNA-dependent molecular pathways that control stromal-epithelial cell signalling. These pathways are currently poorly understood and insights may lead to new therapeutic opportunities.
Methodology
I will identify microRNAs whose expression within fibroblasts is altered during carcinogenesis. I have micro-dissect normal fibroblasts (NFs) and CAFs from a case of breast cancers and determined microRNA expression patterns using microarrays. Similarly, I identified such microRNAs in a tissue culture model in which immortalised breast fibroblasts were cultured either alone (model for NFs) or co-cultured with a breast carcinoma cell line (model for CAFs). MicroRNAs that showed consistent changes in expression between NFs and CAFs in the tissue study and from the tissue culture model were selected. Expression of 10 microRNAs (selected because of >10 fold change or their evidence in literature for a role in cancer/fibroblast function), were examined initially using q-PCR. 4 miRNA have been identified as being consistently down-regulated in all the samples examined. These miRNA(miR-30b, miR-23b, miR-10a, let-7g) will be further examined using qPCR in further clinical samples. This expression will also be confirmed using ISH in a large panel of matched clinical NFs and CAFs from breast cancers.
Having demonstrated consistent expression changes for some microRNAs, I will examine their functional roles. I will identify their predicted targets using bioinformatics tools and will develop experimental approaches to modify microRNA expression, thereby working to validate these targets. Finally, I will investigate roles of these miRNAs in fibroblasts in controlling, first, behaviour of the fibroblasts themselves, and, secondly, in regulating influences of fibroblasts on epithelial cancer cells.
Scientific and Medical Opportunities
This study will add to the growing evidence for the importance of stromal fibroblasts in cancer biology as well as giving new insights into roles for microRNAs in epithelial:stromal interactions. MicroRNAs identified could have roles as prognostic/predictive factors. Furthermore, these microRNA and the molecules they regulate could serve as targets for developing newer treatments directed at the stromal compartment of cancers.
During carcinogenesis, epithelial cells and adjacent stromal fibroblasts both exhibit changes in gene expression. Molecular pathways responsible for these changes are better researched and understood in epithelial cells than in fibroblasts, despite the fact that fibroblasts adjacent to carcinoma cells (carcinoma-associated fibroblasts, CAFs) have important influences on cancer behaviour. MicroRNAs are newly discovered regulators of gene expression, which have roles in the control of proliferation and apoptosis. Importantly, critical roles for microRNAs as tumour-suppressor genes and oncogenes have been identified in the epithelial cells of many cancers. Potential analogous roles for microRNAs within stromal fibroblasts during carcinogenesis remain un-explored.
Aims
I will elucidate microRNA-dependent molecular pathways that control stromal-epithelial cell signalling. These pathways are currently poorly understood and insights may lead to new therapeutic opportunities.
Methodology
I will identify microRNAs whose expression within fibroblasts is altered during carcinogenesis. I have micro-dissect normal fibroblasts (NFs) and CAFs from a case of breast cancers and determined microRNA expression patterns using microarrays. Similarly, I identified such microRNAs in a tissue culture model in which immortalised breast fibroblasts were cultured either alone (model for NFs) or co-cultured with a breast carcinoma cell line (model for CAFs). MicroRNAs that showed consistent changes in expression between NFs and CAFs in the tissue study and from the tissue culture model were selected. Expression of 10 microRNAs (selected because of >10 fold change or their evidence in literature for a role in cancer/fibroblast function), were examined initially using q-PCR. 4 miRNA have been identified as being consistently down-regulated in all the samples examined. These miRNA(miR-30b, miR-23b, miR-10a, let-7g) will be further examined using qPCR in further clinical samples. This expression will also be confirmed using ISH in a large panel of matched clinical NFs and CAFs from breast cancers.
Having demonstrated consistent expression changes for some microRNAs, I will examine their functional roles. I will identify their predicted targets using bioinformatics tools and will develop experimental approaches to modify microRNA expression, thereby working to validate these targets. Finally, I will investigate roles of these miRNAs in fibroblasts in controlling, first, behaviour of the fibroblasts themselves, and, secondly, in regulating influences of fibroblasts on epithelial cancer cells.
Scientific and Medical Opportunities
This study will add to the growing evidence for the importance of stromal fibroblasts in cancer biology as well as giving new insights into roles for microRNAs in epithelial:stromal interactions. MicroRNAs identified could have roles as prognostic/predictive factors. Furthermore, these microRNA and the molecules they regulate could serve as targets for developing newer treatments directed at the stromal compartment of cancers.
