Phosphoproteomics identify arachidonic-acid-regulated signal transduction pathways modulating macrophage functions with implications for ovarian cancer

Abstract

Arachidonic acid (AA) is a polyunsaturated fatty acid present at high concentrations in the ovarian cancer (OC) microenvironment and associated with a poor clinical outcome. In the present study, we have unraveled a potential link between AA and macrophage functions. Methods: AA-triggered signal transduction was studied in primary monocyte-derived macrophages (MDMs) by phosphoproteomics, transcriptional profiling, measurement of intracellular Ca 2+ accumulation and reactive oxygen species production in conjunction with bioinformatic analyses. Functional effects were investigated by actin filament staining, quantification of macropinocytosis and analysis of extracellular vesicle release. Results: We identified the ASK1 - p38δ/α (MAPK13/14) axis as a central constituent of signal transduction pathways triggered by non-metabolized AA. This pathway was induced by the Ca 2+ -triggered activation of calmodulin kinase II, and to a minor extent by ROS generation in a subset of donors. Activated p38 in turn was linked to a transcriptional stress response associated with a poor relapse-free survival. Consistent with the phosphorylation of the p38 substrate HSP27 and the (de)phosphorylation of multiple regulators of Rho family GTPases, AA impaired actin filament organization and inhibited actin-driven macropinocytosis. AA also affected the phosphorylation of proteins regulating vesicle biogenesis, and consistently, AA enhanced the release of tetraspanin-containing exosome-like vesicles. Finally, we identified phospholipase A 2 group 2A (PLA2G2A) as the clinically most relevant enzyme producing extracellular AA, providing further potentially theranostic options. Conclusion: Our results suggest that AA contributes to an unfavorable clinical outcome of OC by impacting the phenotype of tumor-associated macrophages. Besides critical AA-regulated signal transduction proteins identified in the present study, PLA2G2A might represent a potential prognostic tool and therapeutic target to interfere with OC progression.

Butein-instigated miR-186-5p-dependent modulation of TWIST1 affects resistance to cisplatin and bioenergetics of Malignant Pleural Mesothelioma cells

“…In fact, we showed that, besides the effect on cell invasion and 3D growth, buteinmodulated TWIST1 affects cisplatin resistance. A similar effect has recently been shown in epithelial ovarian cancer cells, where TWIST1 delineates a chemoresistant ovarian cancer phenotype [48][49][50] .…”

“…Such findings are in line with what we and others showed on the anticancer action of butein, i.e., that it inhibits migration, invasion, clonogenicity, and resistance of the cells to chemo-therapeutics [18] . The effect of butein on TWIST1 matches what is known of the ability of TWIST1 to impinge on AKT signaling and drive resistance to cisplatin [50] . However, this may not be the only mechanism for butein: for example, target prediction of the buteinmodulated microRNAs suggested that additional targets may mediate the chemo-sensitization effect of butein (data not shown).…”

Review of Mendelian Randomization Studies on Ovarian Cancer

“…AA is a polyunsaturated fatty acid present at high concentrations in the OC microenvironment and associated with poor clinical outcomes. Several studies support its utility as a therapeutic target for intervention and prognostic indicator of OC (103). However, an MR study on female patients of European descent revealed no association of AA with OC risk (38).…”

Arachidonic acid drives adaptive responses to chemotherapy-induced stress in malignant mesothelioma

“…Finally yet importantly, the data shown here may be relevant for other chronic inflammation-related neoplasms. For example, the levels of AA in peritoneal fluids from ovarian carcinoma patients were shown to hold prognostic value [ 81 ] and a recent “omics” profiling of ovarian cancer-derived, AA treatment of mononuclear cells revealed important pathway activation, among all deregulation of MAPK and Rho-GTPase signaling [ 82 ]. Additionally AA secreted by adipocytes, inhibited cisplatin-induced apoptosis of ovarian cancer cells [ 83 ], further supporting our observations.…”