How does integrin alpha-v beta-6-dependent de-regulation of the stroma control alpha-v beta-6-dependent metastasis?
Lead Research Organisation:
Queen Mary University of London
Department Name: Barts Cancer Institute
Abstract
Our lab has published many reports showing that the molecule called alpha-v beta-6 (avb6) which appears on the surface of cancer cells but is not usually on normal cells, is responsible for the ability of many types of cancer to grow and to reduce the life span of cancer patients. We have now shown that the main reason why avb6 shortens the lifespan of cancer patients is that it causes the cancers to spread around the body, and it is the formation of these secondary tumours which is the life-threatening aspect of most cancers. However, exactly how avb6 causes cancers to metastasise is not
known.
Recently we discovered that avb6 does something unusual. We examined all the genes that were changed in a cancer that had avb6 and found that the most changed sets of genes were involved in proteins you find in the space surrounding the cancer cells, the so-called stroma. There were 5 genes in particular that were changed called adiponectin, tenascin X and podocan that were reduced, and SPOCK1 and endocan that were increased. These adiponectin, tenascin X and podocan can be produced by fat cells called adipocytes in the stroma and SPOCK1 and endocan can be produced by fibroblasts in the stroma. The results seemed to suggest that the presence of adiponectin, tenascin X and podocan and the absence of SPOCK1 and endocan seemed to prevent cancers from being so life threatening. When we put adiponectin, tenascin X and podocan onto cancer cells in the laboratory their ability to grow and to invade was actually dramatically reduced. So having adiponectin, tenascin X and podocan, but no SPOCK1 and endocan slows cancers down and extends overall survival. The problem is that if the cancer has avb6 then this molecule somehow changes the behaviour of the adipocytes and fibroblasts and reverses the natural appearance of these proteins: so adiponectin, tenascin X and podocan disappear and SPOCK1 and endocan appear. We need to understand how avb6 can do this.
This study investigates exactly how avb6 changes the adipocytes and fibroblasts to become helpers of cancer growth and
spread but also investigates how the 5 proteins reduce the hazardous behaviour of the cancer cells so that we might find drugs that can copy their effects.
known.
Recently we discovered that avb6 does something unusual. We examined all the genes that were changed in a cancer that had avb6 and found that the most changed sets of genes were involved in proteins you find in the space surrounding the cancer cells, the so-called stroma. There were 5 genes in particular that were changed called adiponectin, tenascin X and podocan that were reduced, and SPOCK1 and endocan that were increased. These adiponectin, tenascin X and podocan can be produced by fat cells called adipocytes in the stroma and SPOCK1 and endocan can be produced by fibroblasts in the stroma. The results seemed to suggest that the presence of adiponectin, tenascin X and podocan and the absence of SPOCK1 and endocan seemed to prevent cancers from being so life threatening. When we put adiponectin, tenascin X and podocan onto cancer cells in the laboratory their ability to grow and to invade was actually dramatically reduced. So having adiponectin, tenascin X and podocan, but no SPOCK1 and endocan slows cancers down and extends overall survival. The problem is that if the cancer has avb6 then this molecule somehow changes the behaviour of the adipocytes and fibroblasts and reverses the natural appearance of these proteins: so adiponectin, tenascin X and podocan disappear and SPOCK1 and endocan appear. We need to understand how avb6 can do this.
This study investigates exactly how avb6 changes the adipocytes and fibroblasts to become helpers of cancer growth and
spread but also investigates how the 5 proteins reduce the hazardous behaviour of the cancer cells so that we might find drugs that can copy their effects.
Technical Summary
The integrin alpha-v beta-6 (avb6) is over-expressed by one third of carcinomas but is weak or absent on most normal
tissues.High avb6 levels correlates with poor overall survival in many cancers including breast and pancreas. Recently we have shown conclusively in transgenic models of breast cancer (MMTV/Erb2/c-neu) and pancreas cancer (PDX-Cre/p53+/-/Ras-G12D/dusp6-/-) that avb6 drives metastasis, but the molecular basis for this is unknown.
Analysis of the transcriptional regulation (RNAseq) of avb6-knockout MMTV/Erb2/c-neu versus wild-type, and MMTV/Erb2/c-neu animals treated with avb6-blocking antibdies or IgG, showed that the dominant signalling pathways de-regulated by avb6 expression are of the matrisome. Bioinformatic analysis showed that of the most deregulated genes (ADIPOQ, TNXB, PODN, SPOCK1 and ESM1) a similar expression in multiple different cancers (TCGA) correlated with overall survival. In pilot studies we discovered that adiponectin, tenascin X and podocan recombinant proteins suppressed proliferation of breast cancer cells and fibroblasts and inhibited the growth and invasion of cancer cells in 3D organotypic gels. We also showed that multiple receptor tyrosine kinase signalling pathways were suppressed.
Using a combination of scRNAseq, RNAseq and phospho-proteomics we shall determine 1.if avb6 regulates transcription of the 5 genes via TGFb activation or MMP release 2. how adipocyte and fibroblast transcription is changed by avb6 on breast cancers 3. How the matrisomal proteins regulate cancer cell signals to suppress their growth and invasion and hopefully identify druggable targets 4. Prove whether suppression of cancer growth and metastasis is driven directly by these matrisomal proteins in vivo.
tissues.High avb6 levels correlates with poor overall survival in many cancers including breast and pancreas. Recently we have shown conclusively in transgenic models of breast cancer (MMTV/Erb2/c-neu) and pancreas cancer (PDX-Cre/p53+/-/Ras-G12D/dusp6-/-) that avb6 drives metastasis, but the molecular basis for this is unknown.
Analysis of the transcriptional regulation (RNAseq) of avb6-knockout MMTV/Erb2/c-neu versus wild-type, and MMTV/Erb2/c-neu animals treated with avb6-blocking antibdies or IgG, showed that the dominant signalling pathways de-regulated by avb6 expression are of the matrisome. Bioinformatic analysis showed that of the most deregulated genes (ADIPOQ, TNXB, PODN, SPOCK1 and ESM1) a similar expression in multiple different cancers (TCGA) correlated with overall survival. In pilot studies we discovered that adiponectin, tenascin X and podocan recombinant proteins suppressed proliferation of breast cancer cells and fibroblasts and inhibited the growth and invasion of cancer cells in 3D organotypic gels. We also showed that multiple receptor tyrosine kinase signalling pathways were suppressed.
Using a combination of scRNAseq, RNAseq and phospho-proteomics we shall determine 1.if avb6 regulates transcription of the 5 genes via TGFb activation or MMP release 2. how adipocyte and fibroblast transcription is changed by avb6 on breast cancers 3. How the matrisomal proteins regulate cancer cell signals to suppress their growth and invasion and hopefully identify druggable targets 4. Prove whether suppression of cancer growth and metastasis is driven directly by these matrisomal proteins in vivo.
People |
ORCID iD |
| John Marshall (Principal Investigator) | |
| Kate Moore (Researcher) |