Abstract

Metastatic seeding by disseminated cancer cells principally occurs in perivascular niches. Here, we show that mechanotransduction signalling triggered by the pericyte-like spreading of disseminated cancer cells on host tissue capillaries is critical for metastatic colonization. Disseminated cancer cells employ L1CAM (cell adhesion molecule L1) to spread on capillaries and activate the mechanotransduction effectors YAP (Yes-associated protein) and MRTF (myocardin-related transcription factor). This spreading is robust enough to displace resident pericytes, which also use L1CAM for perivascular spreading. L1CAM activates YAP by engaging β1 integrin and ILK (integrin-linked kinase). L1CAM and YAP signalling enables the outgrowth of metastasis-initiating cells both immediately following their infiltration of target organs and after they exit from a period of latency. Our results identify an important step in the initiation of metastatic colonization, define its molecular constituents and provide an explanation for the widespread association of L1CAM with metastatic relapse in the clinic.

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Acknowledgements

We acknowledge members of the MSKCC Molecular Cytology Core and Pathology Core Facilities for their assistance with staining, tissue processing, image acquisition and analysis and Young-Mi Kim for help with YAP activity assays. This work was supported by NIH grants P01-CA094060, P01-CA129243 (J.M.) and P30-CA008748 (Memorial Sloan Ketterin Cancer Center), T32-CA009207 (K.G.), DOD Innovator award W81XWH-12-0074 (J.M.), and the Alan and Sandra Gerry Metastasis Research Initiative (J.M.), Shulamit Katzman Endowed Postdoctoral Research Fellowships (E.E.E. and K.G.), an AACR Basic Cancer Research Fellowship and Conquer Cancer Foundation of ASCO Young Investigator Award (K.G.).

Author information

Author notes

    • Manuel Valiente

    Present address: Brain Metastasis Group, Spanish National Cancer Research Center (CNIO), Madrid, Spain

    • Filippo G. Giancotti

    Present address: Department of Cancer Biology and David E. Koch Center for Applied Research of Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

    • Srinivas Malladi

    Present address: Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, TX, USA

  1. These authors contributed equally: Manuel Valiente, Karuna Ganesh.

Affiliations

  1. Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA

    • Ekrem Emrah Er
    • , Manuel Valiente
    • , Karuna Ganesh
    • , Yilong Zou
    • , Saloni Agrawal
    • , Jing Hu
    • , Bailey Griscom
    • , Filippo G. Giancotti
    • , Srinivas Malladi
    •  & Joan Massagué
  2. Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA

    • Karuna Ganesh
  3. Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA

    • Marc Rosenblum
    •  & Edi Brogi
  4. Department of Neurology, Memorial Sloan Kettering Cancer Center, New York, NY, USA

    • Adrienne Boire
  5. Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA

    • Adrienne Boire
  6. Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA

    • Melitta Schachner
  7. Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China

    • Melitta Schachner

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Contributions

E.E.E., M.V. and J.M. conceptualized the project. E.E.E., M.V., K.G. and S.M. designed and performed the experiments. Y.Z. performed bioinformatics analyses. S.A. and B.G. assisted with the experiments. F.G.G. contributed to experimental design. M.S. provided the L1camflox mice. E.B., A.B. and M.R. provided clinical samples and interpretation. KG. and M.V. provided critical editing for the manuscript. E.E.E., and J.M. wrote the manuscript.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Joan Massagué.

Integrated supplementary information

  1. Supplementary Figure 1 Pericytic spreading of metastatic cells.

    (a) Representative images of CellTracker+ cells (green) co-cultured with endothelial tubes (bright field) on matrigel (scale bar, 20 μm). (b) Representative images of GFP+ H2030-BrM (white), CD31+ endothelial cells (red) and CSPG4+ pericytes (green) in cultured brain tissue. Right panels are insets. Yellow arrows indicate pericytes 1) displaced, 2) localized across from the cancer cells and 3) stomped on (scale bars, 20 μm). (c) Representative image of a GFP+ MDA231-BrM cell (white) as in b (scale bars, 10 μm). (d-e) Representative immunofluorescence images H2030-BrM cells (GFP, white) and pericytes co-stained with pericyte markers (d) (PDGFRβ, red and CSPG4, green) and oligodendrocyte markers (e) (O4 sulfatide, red and CSPG4, green). Arrowheads: double positive cells (scale bars, 5μm). Figures (a-e) are representative of 2 independent experiments. (f) Representative time lapse confocal images of H2030-BrM control (Ca: white) displacing CSPG4-DsRed+ pericytes (p1, p2 and p3: green) along the endothelium (DiD staining, red) in cultured brain tissue. Right panels, H2030-BrM L1CAM knockdown cells interacting with pericytes (p1-p3, DsRed: green). Arrows: direction of cancer cell movement in the next frame; solid circles: stalling. L1CAM knockdown cells eventually round up. Images are representative of 4 (Control) and 3 (shL1CAM) independent experiments (scale bars, 10 μm). (g) Mean pericyte coverage in cancer cell invested versus adjacent uninvolved vasculature depicted in Fig. 1d (n = 62, 55, 83, 96 vessels per H2030-BrM “+”, “-”, MDA231-BrM “+”, “-” cancer cell groups pooled from 2 independent experiments). P values are calculated using Mann-Whitney test. Error bars, S.E.M. (h) Immunohistochemistry images of metastatic cells (white arrowheads and L1CAM staining) interacting with pericytes and vascular smooth muscle cells (alpha-smooth muscle actin staining, brown) along the vascular wall (red dotted line) in clinically silent micrometastases in brain tissue obtained during autopsy of a treatment-naïve ER+ breast cancer patient (scale bars, 50 μm). (i) Immunofluorescence staining of brain tissue in (h) for pericytes (aSMA staining, green), endothelial cells (CD31 staining, red) and cancer cells (panKeratin staining, white) (scale bar, 5μm). Data in h-i is from one biological replicate. See Supplementary Table 1 for statistics source data.

  2. Supplementary Figure 2 Initiation of metastatic colonization in multiple organs.

    (a) Confocal images of GFP+ MDA231-BrM (green) cells spreading along the mouse brain vasculature (lectin staining, red) after infiltrating the brain parenchyma of a mouse via the arterial circulation 7 d after injection (scale bar, 20μm). (b) GFP+ MDA231-LM cells (green) generating vascular coopting protrusions (arrowheads) over alveolar blood capillaries (lectin staining, red) after extravasation from the venous circulation into the lungs of a mouse, 2 d after tail vein injection. Dotted lines outline alveolar space (as) (scale bar, 20μm). (c) L1CAM immunoblot in MDA-MB-468 cells. GAPDH, loading control. (d) Confocal images of MDA-MB-468 cells (CellTracker, green) spreading over the vasculature (Lectin staining, red) in brain slice culture assays (scale bar, 20μm). Experiments in (a-d) are representative of 2 independent experiments. (e) Quantitation of roundness index as an inverse measure of cell spreading in MDA-MB-468 cells expressing control or L1CAM overexpression constructs as in (c-d) (n = 158 and 170 cells pooled from 2 independent experiments). Red lines, median. (f) Representative images of GFP+ MDA231-LM control and L1CAM knockdown cells (green) in lungs harvested from the mice in (a) (scale bar, 100 μm). Data on the right are metastatic lesion size in μm2 (n = 132 and 84 metastatic foci per control and shL1CAM groups pooled from 2 mice each). P-values in (e-f) are calculated by Mann-Whitney test. (g) Representative confocal image of 393N1 mouse metastatic cells (GFP staining, green) colonizing the brain of syngeneic mice and spreading over brain capillaries (CD31 staining, red) (scale bar, 50 μm). Data represent 2 biological replicates. (h) Mean luciferase units of MDA231-BoM, HCT116, 786M1A cells measured by CellTiter-Glo in monolayer cultures in vitro (n = 3 independent experiments in triplicates). Error bars, S.E.M. (i-j) Cell viability (CellTiter-Glo)(i) and cell death (Caspase-Glo)(j) activities in H2030-BrM and MDA231-BrM after they have been cultured for 24 h in suspension (n = 3 independent experiments in triplicate). Data in (i-j) are mean relative luciferase units (RLU) and mean arbitrary units (A.U.). Error bars, S.E.M. See Supplementary Figure 8 for unprocessed blots. See Supplementary Table 1 for statistics source data.

  3. Supplementary Figure 3 L1CAM requirement for metastatic colonization post-extravasation.

    (a) Doxycycline inducible L1CAM shRNA lenti-viral vector design. T3G, doxycycline inducible promoter controlling DsRed and L1CAM shRNA expression. PGK, phosphoglycerate kinase promoter for constitutive Venus fluorescent protein expression. (b) Flow cytometry analysis of L1CAM surface expression in the indicated cell lines in the absence (green) or presence (red) of doxycycline. (c) Counter plot representation of data in (c) Red and green scatter plots correspond to red and green histograms in (c). Median intensity: median fluorescence intensity. FSC: forward scatter. (d) Example of the gating strategy used for the flow cytometry experiments in (b-c). (e) Immunohistochemical L1CAM staining showing knockdown efficiency in lungs and brain of metastasis bearing mice. Yellow dotted line separates L1CAM+ brain parenchyma from H2030-BrM lesion with L1CAM knockdown (scale bars, 50 μm). Data in (b-e) are representative of 2 biological replicates. (f) BLI intensity measurements in mice injected with cells carrying doxycycline inducible control vector and treated with or without doxycycline in the diet as in Fig. 3a (n = 8 and 10 mice for control and +dox groups from one experiment with each biological replicate shown). Red lines, median. P values are calculated using Mann-Whitney test. See Supplementary Table 1 for statistics source data.

  4. Supplementary Figure 4 L1CAM requirement for vascular cooption and outgrowth of breast cancer cells exiting from metastatic latency.

    (a) Representative images of elongated, rounded, intermediate and clustered (multiple) HCC1954-LCC1 cells found in the brain of mice 9 days after intracardiac injection of control or L1CAM knockdown cells (scale bar, 10μm). Data represent 2 biological replicates per group. Data to the right represent the number of cells belonging to each phenotypic category for control and L1CAM knockdown cells observed in the brains. Lines, mean (n = 72 and 45 cells for control and shL1CAM groups from 2 mice per condition). (b) GFP+ HCC1954-LCC1 cell (green) morphology in the brain microvasculature (lectin staining, red). Top panels: representative images of cells 2 weeks after intracardiac injection with no NK cell depletion. (1) and (2) represent round and spread cells prior to NK cell depletion. Bottom panels: Representative images of cooptive growth of HCC1954-LCC1 cells s 3 weeks after initiation of anti-asialo-GM1 antibody injections to deplete NK cells (scale bars, 10 μm). Data represent 2 (no NK cell depletion) and 5 (three weeks after NK cell depletion) biological replicates. (c) BLI intensity measurements in mice injected with cells carrying doxycycline inducible control vector and treated with or without doxycycline in the diet as in Fig. 4b. n.s., not significant (n = 6 and 5 mice per “–” and “+” groups). Red lines, median. P values are calculated using Mann-Whitney test. Data represent one experiment with each biological replicate shown. (e) Immunoblot images of L1CAM knockdown with doxycycline treatment in HCC1954-LCC1 cells infected with TetON-shL1CAM vector. Data represent 2 independent experiments. (f) Images of Ki67+ (green) HCC1954-LCC1 cells (white) along the vasculature (lectin staining, red) in Fig. 4. Data represent 5 biological replicates per group. See Supplementary Figure 8 for unprocessed blots. See Supplementary Table 1 for statistics source data.

  5. Supplementary Figure 5 L1CAM mediated re-wiring of transcriptional programs.

    (a) Heat map of differential gene expression with unsupervised clustering. TRAP RNA sequencing results of H2030-BrM control and L1CAM knockdown cells in BSCs described in Fig. 5a are shown as normalized row z-scores. (b) Top five gene signatures from the TRAP data in (a) ranked based on GSEA normalized enrichment scores (NES). FDR, false discovery rate. Data in (a-b) are from 2 biological replicates. (c) Relative mean expression of YAP target genes ANKRD1, ITGB2, and CTGF in H2030-BrM cells transiently expressing the indicated constructs. YAPWT: YAP Wildtype; YAP5SA: constitutively nuclear YAP mutant; YAPS94A: TEAD binding deficient YAP mutant (n = 4 independent experiments in triplicate). (d) Relative mean expression of MRTF-A target genes in indicated cell lines. MKL1: gene name for MRTF-A. Data are from n = 3 biological replicates. Error bars in (c-d): S.E.M. (e) Fluorescence and bright field images of MDA231-BrM cells in 2D culture 24 hours after addition of small molecule stabilizer with indicated treatments. LatA: Latrunculin A (scale bar, 50μm). Data represent 2 biological replicates. (f) Immunoblots showing RFP protein accumulation in indicated cells with indicated treatments. GFP, loading control. Data represent 2 biological replicates. (g) Immunoblot analysis of phosphorylation of Hippo pathway kinases LATS1 and MST1 in cells plated on collagen for 1 hour. GAPDH loading control. Data represent 3 biological replicates. (h) Mean relative luciferase units in indicated cell lines measured by CellTiter-Glo in monolayer cultures in vitro. Error bars, S.E.M. (n = 3 independent experiments in triplicate). (i) Images of indicated H2030-BrM cells in BSCs (scale bars, 10 μm). Data represent 2 biological replicates. Dot plots: roundness index. Red lines, median (n = 45, 53 and 53 cells for Control, shYAP#1 and shYAP#2 cells pooled from 2 independent experiments). P values are calculated using Mann-Whitney test. (j) YAP immunoblots in indicated cells with or without doxycycline treatment. TetON-shYAP: Doxycycline inducible YAP shRNA construct. Data represent 2 biological replicates. See Supplementary Figure 8 for unprocessed blots. See Supplementary Table 1 for statistics source data.

  6. Supplementary Figure 6 L1CAM regulates YAP nuclear localization.

    (a) Mean IHC scoring summary table of serially sectioned and stained patient samples that contain L1CAM+ metastatic cancer cells. Data are from 10 different patients (n = 15, 10, 6, 4, 3, 3, 4, 8, 8, 8 fields of view for patients A-J). Error values are S.D. (b) Single cell image analysis of L1CAM staining intensity with YAP nuclear staining intensity in serially sectioned patient IHC samples. Automated alignment is achieved assigning metastatic cells (L1CAM+, brown circles) to the nearest nucleus in the YAP image (green filled circles). Graphs to the right demonstrate L1CAM staining intensity correlation with YAP staining intensity. P values are calculated by linear regression (n = 159 and 611 cells for upper and lower panels in one field of view shown. Data represent 2 field of views calculated per patient). (c) YAP immunostaining of GFP+ H2030-BrM control and L1CAM knockdown cells on capillaries (Collagen IV staining) in brain tissue cultures depicted in Fig. 6c. Data represent 2 independent experiments. (d) YAP immunostaining of GFP+ MDA231-LM control and L1CAM knockdown cells spreading on vessels in mouse lungs in vivo, 2 days after tail vein injection depicted in Fig. 6d. Cancer cell GFP is cytoplasmic due to its nuclear export signal sequence (scale bars, 10 μm). Data represent 2 biological replicates. (e) Mean relative luciferase units of indicated H2030-BrM and MDA231-BrM cells in vitro, measured by CellTiter-Glo. YAP5SA: constitutively nuclear YAP, YAPS94A: TEAD binding deficient YAP. (n = 3 independent experiments done in three technical replicates). Error bars, S.E.M. See Supplementary Table 1 for statistics source data.

  7. Supplementary Figure 7 L1CAM regulates integrin-ILK signaling.

    (a-b) Median Lung and whole body BLI intensities of mice injected with indicated cells and treated as indicated. TetOn-shILK: Doxycycline inducible ILK shRNA construct. (n = 9, 8, 10 and 9 mice per MDA231-LM control, Dox +, MDA231-BoM control and Dox + groups) (c) Representative images of active β1 integrin immunofluorescence (12G10 staining) in Fig. 8d in the indicated H2030-BrM cells plated on indicated substrates.. 12G10 antibody recognizes the β1 integrins specifically in their active confirmation (scale bar, 10 μm). Data represent 2 independent experiments. (d) Immunoblots of Ankyrin B (AnkB) and L1CAM co-immunoprecipitation (IP) in H2030-BrM cells. Input: whole cell lysate Data represent from 2 independent experiments (e) Median integrated active β1 integrin immunofluorescence intensity in indicated cells measured as in Fig. 8d (n = 320 and 268 cells for Control and shANK2 groups pooled from 2 independent experiments). (f) Representative ex vivo BLI images of mouse brains in Fig. 8k (j) (f) (s). In a-b, and e red lines, median and P values are calculated using Mann-Whitney test. Data in a-b are from one experiment with each biological replicate shown See Supplementary Figure 8 for unprocessed blots. See Supplementary Table 1 for statistics source data.

  8. Supplementary Figure 8

    Unprocessed western blots.

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https://doi.org/10.1038/s41556-018-0138-8

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