Targeting fibroblast activation protein inhibits tumor stromagenesis and growth in mice
01 Dec 2009-Journal of Clinical Investigation (American Society for Clinical Investigation)-Vol. 119, Iss: 12, pp 3613-3625
TL;DR: Results indicate that FAP depletion inhibits tumor cell proliferation indirectly, increases accumulation of collagen, decreases myofibroblast content, and decreases blood vessel density in tumors, providing proof of principle that targeting stromal cell-mediated modifications of the tumor microenvironment may be an effective approach to treating epithelial-derived solid tumors.
Abstract: Membrane-bound proteases have recently emerged as critical mediators of tumorigenesis, angiogenesis, and metastasis. However, the mechanisms by which they regulate these processes remain unknown. As the cell surface serine protease fibroblast activation protein (FAP) is selectively expressed on tumor-associated fibroblasts and pericytes in epithelial tumors, we set out to investigate the role of FAP in mouse models of epithelial-derived solid tumors. In this study, we demonstrate that genetic deletion and pharmacologic inhibition of FAP inhibited tumor growth in both an endogenous mouse model of lung cancer driven by the K-rasG12D mutant and a mouse model of colon cancer, in which CT26 mouse colon cancer cells were transplanted into immune competent syngeneic mice. Interestingly, growth of only the K-rasG12D-driven lung tumors was also attenuated by inhibition of the closely related protease dipeptidyl peptidase IV (DPPIV). Our results indicate that FAP depletion inhibits tumor cell proliferation indirectly, increases accumulation of collagen, decreases myofibroblast content, and decreases blood vessel density in tumors. These data provide proof of principle that targeting stromal cell-mediated modifications of the tumor microenvironment may be an effective approach to treating epithelial-derived solid tumors.
Citations
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TL;DR: The current understanding of tumor cell interactions with the tumor stroma is reviewed with a particular focus on cancer-associated fibroblasts and pericytes.
1,109 citations
TL;DR: Findings reveal that multiple cell types contribute to the immunosuppressive tumor microenvironment and will inform therapeutic cancer vaccine design.
Abstract: The stromal microenvironment of tumors, which is a mixture of hematopoietic and mesenchymal cells, suppresses immune control of tumor growth. A stromal cell type that was first identified in human cancers expresses fibroblast activation protein-α (FAP). We created a transgenic mouse in which FAP-expressing cells can be ablated. Depletion of FAP-expressing cells, which made up only 2% of all tumor cells in established Lewis lung carcinomas, caused rapid hypoxic necrosis of both cancer and stromal cells in immunogenic tumors by a process involving interferon-γ and tumor necrosis factor-α. Depleting FAP-expressing cells in a subcutaneous model of pancreatic ductal adenocarcinoma also permitted immunological control of growth. Therefore, FAP-expressing cells are a nonredundant, immune-suppressive component of the tumor microenvironment.
926 citations
TL;DR: The progress made to date and the remaining challenges in bringing CAF-targeted therapies to the clinic are highlighted and the relevant translational advances and potential therapeutic strategies that target CAFs for cancer treatment are highlighted.
Abstract: Current paradigms of cancer-centric therapeutics are usually not sufficient to eradicate the malignancy, as the cancer stroma may prompt tumour relapse and therapeutic resistance. Among all the stromal cells that populate the tumour microenvironment, cancer-associated fibroblasts (CAFs) are the most abundant and are critically involved in cancer progression. CAFs regulate the biology of tumour cells and other stromal cells via cell–cell contact, releasing numerous regulatory factors and synthesizing and remodelling the extracellular matrix, and thus these cells affect cancer initiation and development. The recent characterization of CAFs based on specific cell surface markers not only deepens our insight into their phenotypic heterogeneity and functional diversity but also brings CAF-targeting therapies for cancer treatment onto the agenda. In this Review, we discuss the current knowledge of biological hallmarks, cellular origins, phenotypical plasticity and functional heterogeneity of CAFs and underscore their contribution to cancer progression. Moreover, we highlight relevant translational advances and potential therapeutic strategies that target CAFs for cancer treatment. Cancer-associated fibroblasts (CAFs) are often the most abundant cell type in the tumour microenvironment. Here, Song and colleagues discuss how to target or harness these cells for cancer therapy. They highlight the progress made to date and the remaining challenges in bringing CAF-targeted therapies to the clinic.
879 citations
TL;DR: A comprehensive review on the fundamental role of cancer-associated fibroblasts in shaping the tumor microenvironment and promoting tumor initiation and progression is provided.
Abstract: Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.
646 citations
Cites background from "Targeting fibroblast activation pro..."
...Rho-dependent cytoskeletal remodeling in CAFs was shown to be activated by Palladin, Cav-1, or JAK signaling cascades, and led to Actomyosin contractility and enhanced invasion (Hooper et al., 2010; Goetz et al., 2011; Sanz-Moreno et al., 2011; Brentnall et al., 2012)....
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...CAFs use Rho-dependent signaling pathways to create force-dependent movements by which they migrate and form tracks in the matrix for the neighboring neoplastic cells to follow (Gaggioli et al., 2007; Goetz et al., 2011; Sanz-Moreno et al., 2011)....
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TL;DR: Novel data is reported on the essential crosstalk between cancer cells and cells of the tumor stroma, with an emphasis on the role played by CAFs.
538 citations
References
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TL;DR: Fibroblasts are a key determinant in the malignant progression of cancer and represent an important target for cancer therapies.
Abstract: Tumours are known as wounds that do not heal - this implies that cells that are involved in angiogenesis and the response to injury, such as endothelial cells and fibroblasts, have a prominent role in the progression, growth and spread of cancers. Fibroblasts are associated with cancer cells at all stages of cancer progression, and their structural and functional contributions to this process are beginning to emerge. Their production of growth factors, chemokines and extracellular matrix facilitates the angiogenic recruitment of endothelial cells and pericytes. Fibroblasts are therefore a key determinant in the malignant progression of cancer and represent an important target for cancer therapies.
4,232 citations
TL;DR: Using a coimplantation tumor xenograft model, it is demonstrated that carcinoma-associated fibroblasts extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammaries derived from the same patients.
3,373 citations
TL;DR: Somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B are found.
Abstract: Determining the genetic basis of cancer requires comprehensive analyses of large collections of histopathologically well-classified primary tumours. Here we report the results of a collaborative study to discover somatic mutations in 188 human lung adenocarcinomas. DNA sequencing of 623 genes with known or potential relationships to cancer revealed more than 1,000 somatic mutations across the samples. Our analysis identified 26 genes that are mutated at significantly high frequencies and thus are probably involved in carcinogenesis. The frequently mutated genes include tyrosine kinases, among them the EGFR homologue ERBB4; multiple ephrin receptor genes, notably EPHA3; vascular endothelial growth factor receptor KDR; and NTRK genes. These data provide evidence of somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers--including NF1, APC, RB1 and ATM--and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B. The observed mutational profiles correlate with clinical features, smoking status and DNA repair defects. These results are reinforced by data integration including single nucleotide polymorphism array and gene expression array. Our findings shed further light on several important signalling pathways involved in lung adenocarcinoma, and suggest new molecular targets for treatment.
2,615 citations
TL;DR: It is revealed that fibroblasts have a more profound influence on the development and progression of carcinomas than was previously appreciated and this has important therapeutic implications.
Abstract: It is widely accepted that the development of carcinoma--the most common form of human cancer--is due to the accumulation of somatic mutations in epithelial cells. The behaviour of carcinomas is also influenced by the tumour microenvironment, which includes extracellular matrix, blood vasculature, inflammatory cells and fibroblasts. Recent studies reveal that fibroblasts have a more profound influence on the development and progression of carcinomas than was previously appreciated. These new findings have important therapeutic implications.
2,215 citations
TL;DR: It is shown that a single infusion of the VEGF-specific antibody bevacizumab decreases tumor perfusion, vascular volume, microvascular density, interstitial fluid pressure and the number of viable, circulating endothelial and progenitor cells, and increases the fraction of vessels with pericyte coverage in rectal carcinoma patients.
Abstract: The effects of vascular endothelial growth factor (VEGF) blockade on the vascular biology of human tumors are not known. Here we show here that a single infusion of the VEGF-specific antibody bevacizumab decreases tumor perfusion, vascular volume, microvascular density, interstitial fluid pressure and the number of viable, circulating endothelial and progenitor cells, and increases the fraction of vessels with pericyte coverage in rectal carcinoma patients. These data indicate that VEGF blockade has a direct and rapid antivascular effect in human tumors.
1,904 citations