The multicellular signalling network of ovarian cancer metastases

Abstract

BackgroundTranscoelomic spread is the major route of metastasis of ovarian high‐grade serous carcinoma (HGSC) with the omentum as the major metastatic site. Its unique tumour microenvironment with its large populations of adipocytes, mesothelial cells and immune cells establishes an intercellular signaling network that is instrumental for metastatic growth yet poorly understood.MethodsBased on transcriptomic analysis of tumour cells, tumour‐associated immune and stroma cells we defined intercellular signaling pathways for 284 cytokines and growth factors and their cognate receptors after bioinformatic adjustment for contaminating cell types. The significance of individual components of this network was validated by analysing clinical correlations and potentially pro‐metastatic functions, including tumour cell migration, pro‐inflammatory signal transduction and TAM expansion.ResultsThe data show an unexpected prominent role of host cells, and in particular of omental adipocytes, mesothelial cells and fibroblasts (CAF), in sustaining this signaling network. These cells, rather than tumour cells, are the major source of most cytokines and growth factors in the omental microenvironment (n = 176 vs. n = 13). Many of these factors target tumour cells, are linked to metastasis and are associated with a short survival. Likewise, tumour stroma cells play a major role in extracellular‐matrix‐triggered signaling. We have verified the functional significance of our observations for three exemplary instances. We show that the omental microenvironment (i) stimulates tumour cell migration and adhesion via WNT4 which is highly expressed by CAF; (ii) induces pro‐tumourigenic TAM proliferation in conjunction with high CSF1 expression by omental stroma cells and (iii) triggers pro‐inflammatory signaling, at least in part via a HSP70–NF‐κB pathway.ConclusionsThe intercellular signaling network of omental metastases is majorly dependent on factors secreted by immune and stroma cells to provide an environment that supports ovarian HGSC progression. Clinically relevant pathways within this network represent novel options for therapeutic intervention.

Prostacyclin Released by Cancer-Associated Fibroblasts Promotes Immunosuppressive and Pro-Metastatic Macrophage Polarization in the Ovarian Cancer Microenvironment

“…Cell-free ascites was cryopreserved at −80 °C. Separation of host and tumor cells from the omentum was conducted essentially according to Sommerfeld et al [ 24 ]. Briefly, ADI were isolated from omentum tissue without macroscopic metastatic lesions by digestion with 370 U/mL collagenase (Sigma Aldrich, Taufkirchen, Germany) in adipocyte digestion buffer (5 mM D-Glucose, 1.5% BSA in PBS for 1 h at 37 °C).…”

“…Flow cytometric phenotyping of ascites and omentum cells was performed on a FACS Canto II instrument using Diva Software (BD Biosciences, Heidelberg, Germany) and analysis by FlowJo™ v10.8 Software (BD Life Sciences, Ashland, OR, USA) as already described [ 24 ]. Briefly, tumor cells were stained with anti-human EpCAM-Vioblue (Miltenyi Biotech), TAM with anti-human CD14-FITC (Miltenyi Biotech, Bergisch Gladbach, Germany) and TAT with anti-human CD3-APC (Biolegend, Koblenz, Germany).…”

“…The effect of soluble mediators secreted by ascTAM after stimulation with PGI 2 analog MRE-269 on tumor migration was evaluated in a Transwell assay format using primary ascTU cells, which lacks PTGIR surface expression [ 24 ]. Briefly, CellTracker green CMFAD-labelled ascTU were preincubated with 1:3 diluted CM of MRE-269-stimulated ascTAM for 24 h at 37 °C and 5% CO 2 before tumor cell migration was measured in a Transwell system using10% FCS as chemoattractant for 24 h. CM derived from untreated or PPARβ/δ agonist L165 treated ascTAM as well as from ascTAM stimulated with MRE-269 in the presence of PTGIR antagonist CAY10449 (1 µM) were used as additional controls.…”

“…To determine the influence of the secretome of PGI 2 analog-treated ascTAM on tumor cell adherence to mesothelial layer, we conducted an attachment assay as previously described [ 24 ]. Briefly, a confluent monolayer of omentum-derived MESO was generated on collagen-I-coated (5 μg/cm 2 ; Gibco/Thermo Fisher Scientific, Waltham, MA, USA) 96-well plates by culturing in OCMI/5% FCS.MESOconfluency was evaluated by microscopic imaging ( Supplementary Figure S1 ).…”

PLAA suppresses ovarian cancer metastasis via METTL3-mediated m6A modification of TRPC3 mRNA

“…Epithelial ovarian cancer is the most lethal gynecological malignancy worldwide [ 1 , 2 ]. One of the most important biological characteristics of ovarian cancer is its insidious and rapid spread from the primary tumor into the peritoneal cavity, involving almost all abdominal organs, and distant organs, which contributes to the high death rate of disease [ 3 , 4 ]. Accordingly, it is urgent to understand the biological process of ovarian cancer metastasis, so as to find effective therapeutic target for metastatic ovarian cancer.…”