Cancer-associated fibroblasts (CAFs) drive tumour progression, but the emergence of this cell state is poorly understood. A broad spectrum of metalloproteinases, controlled by the Timp gene family, influence the tumour microenvironment in human cancers. Here, we generate quadruple TIMP knockout (TIMPless) fibroblasts to unleash metalloproteinase activity within the tumour-stromal compartment and show that complete Timp loss is sufficient for the acquisition of hallmark CAF functions. Exosomes produced by TIMPless fibroblasts induce cancer cell motility and cancer stem cell markers. The proteome of these exosomes is enriched in extracellular matrix proteins and the metalloproteinase ADAM10. Exosomal ADAM10 increases aldehyde dehydrogenase expression in breast cancer cells through Notch receptor activation and enhances motility through the GTPase RhoA. Moreover, ADAM10 knockdown in TIMPless fibroblasts abrogates their CAF function. Importantly, human CAFs secrete ADAM10-rich exosomes that promote cell motility and activate RhoA and Notch signalling in cancer cells. Thus, Timps suppress cancer stroma where activated-fibroblast-secreted exosomes impact tumour progression.
At a glance
- Fibroblasts in cancer. Nat. Rev. Cancer 6, 392–401 (2006). &
- Exosomes mediate stromal mobilization of autocrine Wnt-PCP signaling in breast cancer cell migration. Cell 151, 1542–1556 (2012). et al.
- Membrane vesicles as conveyors of immune responses. Nat. Rev. Immunol. 9, 581–593 (2009). , &
- Proteolytic factors in exosomes. Proteomics 13, 1624–1636 (2013). &
- p53 status in stromal fibroblasts modulates tumor growth in an SDF1-dependent manner. Cancer Res. 70, 9650–9658 (2010). et al.
- Expression of p21waf1/Cip1 in stromal fibroblasts of primary breast tumors. Hum. Mol. Genet. 17, 3596–3600 (2008). , , , &
- p16(INK4A) represses the paracrine tumor-promoting effects of breast stromal fibroblasts. Oncogene 32, 2356–2364 (2013). , , &
- Pten in stromal fibroblasts suppresses mammary epithelial tumours. Nature 461, 1084–1091 (2009). et al.
- Caveolin-1-/- null mammary stromal fibroblasts share characteristics with human breast cancer-associated fibroblasts. Am. J. Pathol. 174, 746–761 (2009). et al.
- TGF-beta signaling in fibroblasts modulates the oncogenic potential of adjacent epithelia. Science 303, 848–851 (2004). et al.
- Metalloproteinases and their natural inhibitors in inflammation and immunity. Nat. Rev. Immunol. 13, 649–665 (2013). , &
- The role of tissue inhibitors of metalloproteinases in tumorigenesis and metastasis. Crit. Rev. Clin. Lab. Sci. 45, 291–338 (2008). &
- Individual Timp deficiencies differentially impact pro-MMP-2 activation. J. Biol. Chem. 281, 10337–10346 (2006). et al.
- Cancer associated fibroblasts stimulated by transforming growth factor beta1 (TGF-β 1) increase invasion rate of tumor cells: a population study. Breast Cancer Res. Treat. 110, 39–49 (2008). et al.
- A matrix metalloproteinase expressed on the surface of invasive tumour cells. Nature 370, 61–65 (1994). et al.
- A disintegrin and metalloproteinase 17 (ADAM17) mediates inflammation-induced shedding of syndecan-1 and -4 by lung epithelial cells. J. Biol. Chem. 285, 555–564 (2010). et al.
- Ectodomain shedding of EGFR ligands and TNFR1 dictates hepatocyte apoptosis during fulminant hepatitis in mice. J. Clin. Invest. 120, 2731–2744 (2010). et al.
- The disintegrin-like metalloproteinase ADAM10 is involved in constitutive cleavage of CX3CL1 (fractalkine) and regulates CX3CL1-mediated cell–cell adhesion. Blood 102, 1186–1195 (2003). et al.
- Clear cell renal cell carcinoma with smooth muscle stroma. Hum. Pathol. 40, 425–429 (2009). , , , &
- Carcinoma-associated fibroblasts are a rate-limiting determinant for tumour progression. Semin. Cell Dev. Biol. 21, 19–25 (2010). , &
- Recent advances on the role of tumor exosomes in immunosuppression and disease progression. Semin. Cancer Biol. 22, 342–349 (2012). , , , &
- Intercellular transfer of the oncogenic receptor EGFRvIII by microvesicles derived from tumour cells. Nat. Cell Biol. 10, 619–624 (2008). et al.
- CD90/THY1 is overexpressed in prostate cancer-associated fibroblasts and could serve as a cancer biomarker. Mod. Pathol. 23, 1346–1356 (2010). et al.
- The role of lysyl oxidase in SRC-dependent proliferation and metastasis of colorectal cancer. J. Natl Cancer Inst. 103, 407–424 (2011). et al.
- Breast cancer cells produce tenascin C as a metastatic niche component to colonize the lungs. Nat. Med. 17, 867–874 (2011). et al.
- ADAMs in cancer cell proliferation and progression. Cancer Sci. 98, 621–628 (2007). &
- A role for exosomes in the constitutive and stimulus-induced ectodomain cleavage of L1 and CD44. Biochem. J. 393, 609–618 (2006). et al.
- Cleavage of L1 in exosomes and apoptotic membrane vesicles released from ovarian carcinoma cells. Clin. Cancer Res. 11, 2492–2501 (2005). et al.
- Epithelial stem cells: turning over new leaves. Cell 128, 445–458 (2007). , &
- The role of Adams in Notch signaling. Adv. Exp. Med. Biol. 727, 15–36 (2012). &
- Notch signalling regulates stem cell numbers in vitro and in vivo. Nature 442, 823–826 (2006). et al.
- Aldehyde dehydrogenase activity selects for lung adenocarcinoma stem cells dependent on notch signaling. Cancer Res. 70, 9937–9948 (2010). et al.
- Inhibition of Notch signaling reduces the stem-like population of breast cancer cells and prevents mammosphere formation. Anticancer Res. 30, 3853–3867 (2010). et al.
- Aldehyde dehydrogenase activity of breast cancer stem cells is primarily due to isoform ALDH1A3 and its expression is predictive of metastasis. Stem Cells 29, 32–45 (2011). et al.
- Rho, rac, and cdc42 GTPases regulate the assembly of multimolecular focal complexes associated with actin stress fibers, lamellipodia, and filopodia. Cell 81, 53–62 (1995). &
- Rho signaling, ROCK and mDia1, in transformation, metastasis and invasion. Cancer Metastasis Rev. 28, 65–76 (2009). , &
- Rho kinase inhibitor HA-1077 prevents Rho-mediated myosin phosphatase inhibition in smooth muscle cells. Am. J. Physiol. Cell Physiol. 278, C57–65 (2000). et al.
- Stromal gene expression predicts clinical outcome in breast cancer. Nat. Med. 14, 518–527 (2008). et al.
- Cancer-associated fibroblasts are activated in incipient neoplasia to orchestrate tumor-promoting inflammation in an NF-κB-dependent manner. Cancer cell 17, 135–147 (2010). , , , &
- Autocrine TGF-β and stromal cell-derived factor-1 (SDF-1) signaling drives the evolution of tumor-promoting mammary stromal myofibroblasts. Proc. Natl Acad. Sci. USA 107, 20009–20014 (2010). et al.
- Stromal fibroblasts present in invasive human breast carcinomas promote tumor growth and angiogenesis through elevated SDF-1/CXCL12 secretion. Cell 121, 335–348 (2005). et al.
- The roles of tumor-derived exosomes in cancer pathogenesis. Clin. Dev. Immunol. 2011, 842849 &
- Interactions between cancer stem cells and their niche govern metastatic colonization. Nature 481, 85–89 (2012). et al.
- Cooperation of matrix metalloproteinases with the RhoA/Rho kinase and mitogen-activated protein kinase kinase-1/extracellular signal-regulated kinase signaling pathways is required for the sphingosine-1-phosphate-induced mobilization of marrow-derived stromal cells. Stem Cells 24, 2557–2565 (2006). , , , &
- LOX-1-MT1-MMP axis is crucial for RhoA and Rac1 activation induced by oxidized low-density lipoprotein in endothelial cells. Cardiovasc. Res. 84, 127–136 (2009). et al.
- The process of macrophage migration promotes matrix metalloproteinase-independent invasion by tumor cells. J. Immunol. 187, 3806–3814 (2011). et al.
- EphA2-mediated mesenchymal-amoeboid transition induced by endothelial progenitor cells enhances metastatic spread due to cancer-associated fibroblasts. J. Mol. Med. 91, 103–115 (2013). et al.
- Mice with tissue inhibitor of metalloproteinases 4 (Timp4) deletion succumb to induced myocardial infarction but not to cardiac pressure overload. J. Biol. Chem. 285, 24487–24493 (2010). et al.
- Spontaneous air space enlargement in the lungs of mice lacking tissue inhibitor of metalloproteinases-3 (TIMP-3). J. Clin. Invest. 108, 817–829 (2001). et al.
- TIMP-2 is required for efficient activation of proMMP-2 in vivo. J. Biol. Chem. 275, 26411–26415 (2000). , &
- Targeted mutagenesis of Timp-1 reveals that lung tumor invasion is influenced by Timp-1 genotype of the tumor but not by that of the host. Oncogene 13, 2307–2314 (1996). , , &
- Collagen gel contraction assay. Methods Mol. Biol. 341, 103–109 (2006). , , &
- Prostate tumor growth can be modulated by dietarily targeting the 15-lipoxygenase-1 and cyclooxygenase-2 enzymes. Neoplasia 11, 692–699 (2009). , , , &
- TIMP-3 deficiency in the host, but not in the tumor, enhances tumor growth and angiogenesis. Oncogene 25, 650–655 (2006). , &
- Curr. Protec. Cell Biol., 2006). , , & Isolation and Characterization of Exosomes from Cell Culture Supernatants and Biological Fluids. Ch. 8, Unit 3.22 (
- Characterisation of exosomes derived from human cells by nanoparticle tracking analysis and scanning electron microscopy. Colloids Surfaces B 87, 146–150 (2011). et al.
- Selective transfer of exosomes from oligodendrocytes to microglia by macropinocytosis. J. Cell Sci. 124, 447–458 (2011). et al.
- Peptide separations by on-line MudPIT compared to isoelectric focusing in an off-gel format: application to a membrane-enriched fraction from C2C12 mouse skeletal muscle cells. J. Proteome Res. 8, 4860–4869 (2009). et al.
- Identification of pathways associated with invasive behavior by ovarian cancer cells using multidimensional protein identification technology (MudPIT). Mol. Biosyst. 4, 762–773 (2008). et al.
- MaxQuant enables high peptide identification rates, individualized ppb-range mass accuracies and proteome-wide protein quantification. Nat. Biotechnol. 26, 1367–1372 (2008). &
- A detailed mammosphere assay protocol for the quantification of breast stem cell activity. J. Mammary Gland Biol. Neoplasia 17, 111–117 (2012). et al.
- Targeting CXCR1/2 significantly reduces breast cancer stem cell activity and increases the efficacy of inhibiting HER2 via HER2-dependent and-independent mechanisms. Clin. Cancer Res. 19, 643–656 (2013). et al.
- Constitutive expression and regulated release of the transmembrane chemokine CXCL16 in human and murine skin. J. Invest. Dermatol. 127, 1444–1455 (2007). et al.
- Identification of a subpopulation of cells with cancer stem cell properties in head and neck squamous cell carcinoma. Proc. Natl Acad. Sci. USA 104, 973–978 (2007). et al.
- Supplementary Figure 1: Characterisation of TIMPless fibroblasts. (944 KB)
(a) Relative gene expression of TIMPs1-4 by real time quantitative PCR (RT-qPCR) in WT or ΔTimp fibroblasts (mean ± s.d. (n = 3 independent isolates of primary fibroblasts). (b) Immunoblot of TIMP3 and β-actin in fibroblasts. Arrows indicate 24 kDa and 27 kDa (glycosylated) TIMP3 (ref. 13). (c) α-smooth muscle actin (α-SMA) immunostained mammary gland and lung sections of WT or ΔTimp mice with the highlighted area magnified to the right. Scale bars, 100 μm. (d) Growth curves of WT and ΔTimp fibroblasts. The number of cells per 10 cm dish was quantified every other day (mean ± s.d. (n = 3 dishes)). (e) Growth crisis experiment using WT and ΔTimp fibroblasts. Isolated WT and ΔTimp fibroblasts were grown in a 10 cm dish and passaged when they reached confluence. Note that ΔTimp fibroblasts grew faster than WT fibroblasts at the beginning of culture, however, both WT and ΔTimp fibroblasts underwent a growth crisis marked by failure to proliferate around 40 passages. Results between the two independent groups were determined by Student’s t-test. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Figure 2: Altered metalloproteinase regulation in TIMPless fibroblasts. (380 KB)
(a) RT-qPCR analysis of α-SMA gene expression in fibroblasts. Expression of α-SMA in the presence of TGF-β (mean± s.d. (WT n = 3; ΔTimp n = 4 independent isolates of primary fibroblasts)). (b) Relative gene expression of collagens, type I α1 (Col1a1), type I α2 (Col1a2) and type IV α1 (Col4a1) by RT-qPCR in WT or ΔTimp fibroblasts (mean ± s.d. (n = 3 independent isolates of primary fibroblasts). (c) Analysis of gene expression of MMP2, MMP9, MMP13, MMP14, ADAM10, ADAM12 and ADAM17 in WT or ΔTimp fibroblasts by relative RT-qPCR (mean ± s.d. (n = 4 independent isolates of primary fibroblasts)). (d) Immunoblot of WT and ΔTimp fibroblasts for ADAM10 and ADAM17. Pro-form (p) and mature form (m) of ADAM10 are indicated. (e) RT-qPCR analysis of TGF-β2 gene expression in WT or single or compound Timp deficient fibroblasts (mean ± s.d. (n = 3 independent isolates of primary fibroblasts)). (f) Gelatin zymography of conditioned medium from fibroblasts stimulated with 50 μg ml−1 of concanavalin (con) A as indicated (+). Arrows indicate forms of MMP2 and MMP9. (g) RT-qPCR analysis of SDF-1 and HGF gene expression in WT or ΔTimp fibroblasts in the presence with or without broad metalloproteinase inhibitor BB94 (mean ± s.d. (n = 3 dishes)). Results between the two independent groups were determined by Student’s t-test, and comparisons among three or more groups were determined by one-way ANOVA followed by Bonferroni’s post-hoc testing. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Figure 3: TIMPless fibroblasts augment tumour cell xenografts. (926 KB)
(a) Tumour weight of human cell line xenografts at time of sacrifice (day 35 for MDA-MB231 xenografts, day 28 for A549 xenografts and day 51 for SCC4 xenografts) (mean ± s.d. (MDA-MB231: n = 14 tumours per group; A549: cancer cells alone n = 12 tumours, cancer + WT fibroblasts n = 10 tumours, cancer + ΔTimp fibroblasts n = 10 tumours; SCC4: n = 6 tumours per group). Tumour cells (1 × 106) were implanted with or without fibroblasts (3 × 106) as indicated. (b) Tumour volume measurements of 786-O xenografts subcutaneously injected alone (1 × 106) or with WT or ΔTimp fibroblasts (3 × 106)(mean± s.d. (n = 6 tumours per group)). Note that 786-O xenografts did not grow. (c) Hematoxylin and eosin (HE) staining and von Willebrand factor (vWF) immunostaining of sections from representative MDA-MB231 tumours. Arrows indicate vWF-positive vessels, inset: high-power view. Scale bars, 200 μm. (d) HE staining of sections from representative A549 xenograft tumours. The borders between tumour and stroma are indicated with dotted lines with the highlighted area magnified to the right. Note that xenograft tumours with TIMPless fibroblasts tend to invade the surrounding tissue by forming small cancer cell islands, while xenograft tumours with WT fibroblasts or control tumours had well-demarcated borderlines with the surrounding tissue. Scale bars, 500 μm. (e) Ki-67-immunostained tumour sections (A549 and MDA-MB231). Human cancer cells are labelled with human-specific vimentin (green) and mouse-specific Ki-67 clone Tec3 that stains stromal cells only (red) as indicated by arrows and quantitated per high powered field (HPF) (mean ± s.d. (WT n = 5; ΔTimp n = 5 tumours)). Scale bars, 50 μm. Note that there are very few Ki-67 positive stromal cells in the stroma of these tumour xenografts and there are no significant differences between the number of Ki-67 positive cells in TIMPless and WT groups for both A549 and MDA-MB231 xenografts. P values are indicated on respective plots. Comparisons among three or more groups were determined by one-way ANOVA followed by Bonferroni’s post-hoc testing. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Figure 4: Effects of conditioned medium or purified exosomes from ΔTimp fibroblasts on cancer cell behavior. (966 KB)
(a) The relative cell viability of MDA-MB231 cells treated with control (DMEM), WT or ΔTimp medium for 72 h was evaluated by a CellTiter-Glo proliferation assay (mean ± s.d. (n = 3 wells)). (b) Average migration speed of MDA-MB231 cells incubated with DMEM, WT or ΔTimp medium over 15 h (DMEM: n = 20; WT media: n = 27; ΔTimp media: n = 30 individual cells). (c) Relative cell migration was determined by the number of migrating MDA-MB231 cells in the presence of DMEM, WT or ΔTimp medium in a transwell migration assay (mean ± s.d. (n = 6 wells)). (d) Representative images of A549 cells treated with DMEM (control), WT_exo or ΔTimp_exo. Scale bars, 100 μm. (e) Representative images of migrated A549 cells and quantification of migration in a transwell migration assay (A549 cells in the presence of DMEM, WT_exo or ΔTimp_exo; mean ± s.d. (n = 4 wells)). Scale bars, 100 μm. (f) Internalisation of fibroblast-derived exosomes by MDA-MB231 cells. Exosomes were purified from WT or ΔTimp fibroblasts, labelled with PKH67 (green) and incubated either with living or with fixed MDA-MB231 cells (vimentin, red) for 12 h at 37 °C. Scale bars, 50 μm. Note that PKH67-labelled exosomes from WT or ΔTimp fibroblasts can transfer the PKH67 dye into living, but not fixed MDA-MB231 cells showing that transfer is not due to passive diffusion, but to an active uptake process. (g) Z-stack image of MDA-MB231 cells incubated with PKH67-labelled exosomes from ΔTimp fibroblasts. Scale bars, 20 μm. Note that PKH67 dye is detected inside of the cells. (h) Transwell migration of MDA-MB231 cells in the presence of exosomes from WT or single, compound or complete Timp-deficient fibroblasts (mean ± s.d. (n = 3 wells)). Comparisons among three or more groups were determined by one-way ANOVA followed by Bonferroni’s post-hoc testing. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Figure 5: Summary of detected proteins in WT- or ΔTimp-exosomes by mass spectrometry. (647 KB)
(a) Representative scanning electron-microscope images of whole-mounted exosomes purified from WT or ΔTimp media and their average size (n = 55 vesicles per group). Scale bars, 100 nm. (b) Venn diagrams depicting overlap of proteins identified in three replicate proteomic analyses of purified exosomes. A total of 280 (ΔTimp) and 269 (WT) proteins were identified from the three trials. 272 proteins in ΔTimp-exosomes and 263 proteins in WT-exosomes were identified with high confidence in at least two trials. (c) Ratio of differentially expressed extracellular matrix proteins (GO:0031012) as analysed by Gene Ontology (GO) in ΔTimp- versus WT-exosomes. (d) Intracellular signalling pathways or biological processes representing differentially expressed proteins in exosomes. FDR (%): ECM-receptor interaction (mmu04512) = 0.0004, Focal adhesion (mmu04510) = 0.0007, Cytoskeletal regulation by Rho GTPase (P00016) = 0.7714, Integrin signalling pathway (P00034) = 1.9656, Huntington disease (P00029) = 6.4997, Hedgehog signalling pathway (P00025) = 6.5084. Proteasome (mmu03050) = 7.2460. (e) Representative images of MDA-MB231 cells treated with control media (DMEM), WT_exo or ΔTimp_exo in the presence of metalloproteinase inhibitors for 15 h of culture, high-power view inset. Scale bars, 50 μm. Note that the morphological change of ΔTimp_exo-treated MDA-MB231 cells was completely inhibited in the presence of ADAM10-specific inhibitor GI254023, combined ADAM17/ADAM10 inhibitor GW280264, and broad metalloproteinase inhibitor BB94. Results between the two independent groups were determined by Student’s t-test.
- Supplementary Figure 6: Effects of TIMPless-exosomes on cancer cell stemness. (698 KB)
(a) Relative RT-qPCR analysis of aldehyde dehydrogenase1A1 (ALDH1A1) gene expression in MDA-MB231 cells treated with exosomes in the presence of metalloproteinase or γ-secretase inhibitors (mean ± s.d. (n = 4 dishes)). (b) Relative RT-qPCR analysis of CD44 gene expression in MDA-MB231 cells treated with exosomes in the presence of metalloproteinase inhibitors (mean ± s.d. (n = 3 dishes)). (c) Mammosphere culture and self-renewal assay. Representative images of primary mammosphere formation of MDA-MB231 cells in the presence of WT- or ΔTimp-exosomes for 5 days are shown in the left panels. Scale bars, 50 μm. Mammosphere self-renewal activity is calculated as described in Methods (mean ± s.d. (n = 6 dishes)). (d) Immunoblot of RhoA before, and after GTP pull-down to isolate GTP-bound active RhoA in MDA-MB231 and A549 cells treated as indicated. Results between the two independent groups were determined by Student’s t-test, and comparisons among three or more groups were determined by one-way ANOVA followed by Bonferroni’s post-hoc testing. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Figure 7: Establishment of shADAM10-knockdown in WT and TIMPless fibroblasts and gene expression analysis on human breast cancer stroma. (283 KB)
(a) RT-qPCR analysis showing relative expression of ADAM10 after shRNA knockdown of ADAM10 (shA10) in WT and ΔTimp fibroblasts compared to scrambled shRNA control treated (shCtrl) and non-shRNA treated parental cells (WT and ΔTimp) (mean ± s.d. (n = 3 dishes)). (b) RT-qPCR analysis showing relative expression of ADAM9,12,17 in ΔTimpshCtrl or ΔTimpshA10 fibroblasts (mean ± s.d. (n = 3 dishes)). (c) Relative cell viability of WTshCtrl, WTshA10, ΔTimpshCtrl or ΔTimpshA10 fibroblasts (mean ± s.d. (n = 4 wells)). (d) Log2 expression ratio of TIMPs in murine dysplastic skin fibroblasts (DSFs) from K14-HPV16 mice versus normal dermal fibroblasts (NDFs) from GSE 17817. Average of log2 expression ratio of single probes against TIMP1 (1 probe), TIMP2 (6 probes), TIMP3 (4 probes) and TIMP4 (2 probes) is shown. (e) Gene expression level of ADAM8, ADAM12 and MMP11 in human breast cancer stroma adjacent to invasive ductal carcinoma (tumour, n = 51 patients) versus normal breast reduction tissue (normal, n = 6 patients) from GSE9014. P values smaller than 0.05 are indicated on respective plots. Results between the two independent groups were determined by Student’s t-test. P values smaller than 0.05 are indicated on respective plots.
- Supplementary Information (2,495 KB)