Background: Malignant Pleural Mesothelioma (MPM) is an aggressive disease related to asbestos exposure, with no effective therapeutic options. Methods: We undertook unsupervised analyses of RNA-sequencing data of 284 MPMs, with no assumption of discreteness. Using immunohistochemistry, we performed an orthogonal validation on a subset of 103 samples and a biological replication in an independent series of 77 samples. Findings: A continuum of molecular profiles explained the prognosis of the disease better than any discrete model. The immune and vascular pathways were the major sources of molecular variation, with strong differences in the expression of immune checkpoints and pro-angiogenic genes; the extrema of this continuum had specific molecular profiles: a "hot" bad-prognosis profile, with high lymphocyte infiltration and high expression of immune checkpoints and pro-angiogenic genes; a "cold" badprognosis profile, with low lymphocyte infiltration and high expression of pro-angiogenic genes; and a "VEGFR2+/VISTA+" better-prognosis profile, with high expression of immune checkpoint VISTA and proangiogenic gene VEGFR2. We validated the gene expression levels at the protein level for a subset of five selected genes belonging to the immune and vascular pathways (CD8A, PDL1, VEGFR3, VEGFR2, and VISTA), in the validation series, and replicated the molecular profiles as well as their prognostic value in the replication series. Interpretation: The prognosis of MPM is best explained by a continuous model, which extremes show specific expression patterns of genes involved in angiogenesis and immune response.
The composition of the tumor microenvironment (TME) mediates the outcome of chemo- and immunotherapies in malignant pleural mesothelioma (MPM). Tumor-associated macrophages (TAMs) and monocyte myeloid-derived immunosuppressive cells (M-MDSCs) constitute a major fraction of the TME. As central cells of the innate immune system, monocytes exert well-characterized functions of phagocytosis, cytokine production, and antibody-dependent cell-mediated cytotoxicity (ADCC). The objective of this study was to evaluate the ability of monocytes to exert a direct cytotoxicity by cell-to-cell contact with MPM cells. The experimental model is based on cocultures between human blood-derived monocytes sorted by negative selection and mesothelioma cell lines. Data show (i) that blood-derived human monocytes induce tumor cell death by direct cell-to-cell contact, (ii) that VPA is a pharmacological enhancer of this cytotoxic activity, (iii) that VPA increases monocyte migration and their aggregation with MPM cells, and (iv) that the molecular mechanisms behind VPA modulation of monocytes involve a downregulation of the membrane receptors associated with the M2 phenotype, i.e., CD163, CD206, and CD209. These conclusions, thus, broaden our understanding about the molecular mechanisms involved in immunosurveillance of the tumor microenvironment and open new prospects for further improvement of still unsatisfactory MPM therapies
Background: Liver is a common metastatic site of lung cancer, and patients with liver metastases will progress rapidly. This study aims to access whether certain genomic features could predict the presence of liver metastasis.
Tumor-associated macrophages (TAM) are particularly abundant (i.e. 27% ± 9%) in the microenvironment of malignant pleural mesothelioma (MPM). These macrophages do not correspond to classical (M1) and alternatively-activated (M2) phenotypes but, instead, are shaped by local inflammatory mediators released in the pleura. We previously showed that, besides classical functions exerted by macrophages (i.e. phagocytosis, cytokine expression and antigen presentation), murine RAW264.7 cells are directly cytotoxic to MPM tumors (Hamaidia et al, JCI Insight 4:e128474). Upon direct cell-to-cell contact, RAW264.7 macrophages kill mesothelioma cells by a mechanism of oxeiptosis involving the enhancer of zeste homolog 2 (EZH2) methyltransferase. We have now investigated this immune-editing activity in human mesothelioma. We show that M1-activated primary macrophages are more cytotoxic for M14K cells than M2. The killing activity of M1 macrophages is dependent on NADPH oxidase activity and peroxynitrite levels. Mesothelioma cells and M2 macrophages interact through an inhibitory synapse characterized by engagement of the PD-1 receptor. Consistently, the immune-editing activity of M2 macrophages is partially restored in presence of neutralizing anti-PD1 antibody. Primary human macrophages cultured in presence of pleural effusions of MPM patients are less cytotoxic than M1 and are unable to inhibit tumor growth in mice. Macrophages differentiated in pleural effusions display a broad spectrum of cytotoxic activities (i.e. from complete inactivity to rates similar to those of M2). Luminex profiling of pleural fluids has identified a series of key mediators associated with the cytotoxic phenotype. The best correlation is obtained with resistin (RETN, FIZZ3, ADSF). Recombinant human resistin improves the killing activity of pleural effusion macrophages in cell culture. Gene transduction of RETN in RAW264.7 impairs growth of AB12 tumors in BALB/c mice. In conclusion, we have shown that resistin is the main factor that mediates immunoediting activity exerted by primary human macrophages towards mesothelioma cells, opening new prospects for therapeutic intervention.
Citation Format: Malik Hamaidia, Majeed Jamakhani, Jean-Rock Jacques, Alexis Fontaine, Arnaud Scherpereel, Eric Wasielewski, Louis Renaud, Vincent Heinen, Bernard Duysinx, Luc Willems. Resistin mediates the immunoediting activity exerted by primary human macrophages towards mesothelioma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 663.
Background: Lung cancer is the leading cause of cancer-related mortality worldwide with a 5 year survival rate of 15%. Non-small cell lung cancer (NSCLC) is the most commonly diagnosed form of lung cancer. Cisplatin-based regimens are currently the most effective chemotherapy for NSCLC, however, chemoresistance poses a major
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