Littérature scientifique sur le sujet « Mesenchymal-amoeboid transition (MAT) »

The ability of cancer cells to adopt various migration modes (the plasticity of cancer cell invasiveness) is a substantive obstacle in the treatment of metastasis, yet still an incompletely understood process. We performed a comparison of publicly available transcriptomic datasets from various cell types undergoing a switch between the mesenchymal and amoeboid migration modes. Strikingly, lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) was one of three genes that were found upregulated in all amoeboid cells analyzed. Accordingly, downregulation of MALAT1 in predominantly amoeboid cell lines A375m2 and A2058 resulted in decrease of active RhoA (Ras homolog family member A) and was accompanied by the amoeboid-mesenchymal transition in A375m2 cells. Moreover, MALAT1 downregulation in amoeboid cells led to increased cell proliferation. Our work is the first to address the role of MALAT1 in MAT/AMT (mesenchymal to amoeboid transition/amoeboid to mesenchymal transition) and suggests that increased MALAT1 expression is a common feature of amoeboid cells.

Cancer cell invasion is a precondition for tumour metastasis and represents one of the most devastating characteristics of cancer. The development of drugs targeting cell migration, known as migrastatics, may improve the treatment of highly invasive tumours such as glioblastoma (GBM). In this study, investigations into the role of the cell adhesion protein Cellular communication network factor 1 (CCN1, also known as CYR61) in GBM cell migration uncovered a drug resistance mechanism adopted by cells when treated with the small molecule inhibitor CCG-1423. This inhibitor binds to importin α/β inhibiting the nuclear translocation of the transcriptional co-activator MKL1, thus preventing downstream effects including migration. Despite this reported role as an inhibitor of cell migration, we found that CCG-1423 treatment did not inhibit GBM cell migration. However, we could observe cells now migrating by mesenchymal–amoeboid transition (MAT). Furthermore, we present evidence that CCN1 plays a critical role in the progression of GBM with increased expression in higher-grade tumours and matched blood samples. These findings support a potential role for CCN1 as a biomarker for the monitoring and potentially early prediction of GBM recurrence, therefore as such could help to improve treatment of and increase survival rates of this devastating disease.

Abstract Background The key process of mesenchymal to amoeboid transition (MAT), which enables prostate cancer (PCa) transendothelial migration and subsequent development of metastases in red bone marrow stroma, is driven by phosphorylation of EphA2S897 by pAkt, which is induced by the omega-6 polyunsaturated fatty acid arachidonic acid. Here we investigate the influence of EphA2 signalling in PCa progression and long-term survival. Methods The mechanisms underpinning metastatic biopotential of altered EphA2 signalling in relation to PTEN status were assessed in vitro using canonical (EphA2D739N) and non-canonical (EphA2S897G) PC3-M mutants, interrogation of publicly available PTEN-stratified databases and clinical validation using a PCa TMA (n = 177) with long-term follow-up data. Spatial heterogeneity of EphA2 was assessed using a radical prostatectomy cohort (n = 67). Results Non-canonical EphA2 signalling via pEphA2S897 is required for PCa transendothelial invasion of bone marrow endothelium. High expression of EphA2 or pEphA2S897 in a PTENlow background is associated with poor overall survival. Expression of EphA2, pEphA2S897 and the associated MAT marker pMLC2 are spatially regulated with the highest levels found within lesion areas within 500 µm of the prostate margin. Conclusion EphA2 MAT-related signalling confers transendothelial invasion. This is associated with a substantially worse prognosis in PTEN-deficient PCa.

AbstractMultiple cellular processes, such as immune responses and cancer cell metastasis, crucially depend on interconvertible migration modes. However, knowledge is scarce on how infectious agents impact the processes of cell adhesion and migration at restrictive biological barriers. In extracellular matrix, dendritic cells (DCs) infected by the obligate intracellular protozoan Toxoplasma gondii undergo mesenchymal-to-amoeboid transition (MAT) for rapid integrin-independent migration. Here, in a cellular model of the blood–brain barrier, we report that parasitised DCs adhere to polarised endothelium and shift to integrin-dependent motility, accompanied by elevated transendothelial migration (TEM). Upon contact with endothelium, parasitised DCs dramatically reduced velocities and adhered under both static and shear stress conditions, thereby obliterating the infection-induced amoeboid motility displayed in collagen matrix. The motility of adherent parasitised DCs on endothelial monolayers was restored by blockade of β1 and β2 integrins or ICAM-1, which conversely reduced motility on collagen-coated surfaces. Moreover, parasitised DCs exhibited enhanced translocation across highly polarised primary murine brain endothelial cell monolayers. Blockade of β1, β2 integrins, ICAM-1 and PECAM-1 reduced TEM frequencies. Finally, gene silencing of the pan-integrin-cytoskeleton linker talin (Tln1) or of β1 integrin (Itgb1) in primary DCs resulted in increased motility on endothelium and decreased TEM. Adding to the paradigms of leukocyte diapedesis, the findings provide novel insights in how an intracellular pathogen impacts the migratory plasticity of leukocytes in response to the cellular environment, to promote infection-related dissemination.

Part 1 Growing evidence suggest that bone marrow-derived mesenchymal stem cells (BM-MSCs) are key players in tumor stroma. Here, we investigated the cross-talk between BM-MSCs and osteosarcoma (OS) cells in tumor progression. We revealed a strong tropism of BM-MSCs towards these tumor cells and identified monocyte chemoattractant protein (MCP)-1, growth-regulated oncogene (GRO)-α and transforming growth factor (TGF)-β1 as pivotal factors for BM-MSC chemotaxis. Once in contact with OS cells, BM-MSCs trans-differentiate into cancer-associated fibroblasts, further increasing MCP-1, GRO-α, interleukin (IL)-6 and IL-8 levels in the tumor microenvironment. These cytokines promote mesenchymal to amoeboid transition (MAT), driven by activation of the small GTPase RhoA, in OS cells, as illustrated by the in vitro assay and live imaging. The outcome is a significant increase of aggressiveness in OS cells in terms of motility, invasiveness and trans-endothelial migration. In keeping with their enhanced trans-endothelial migration abilities, OS cells stimulated by BM-MSCs also sustain migration and invasion. Thus, BM-MSC recruitment to the OS site and the consequent cytokine-induced MAT are crucial events in OS malignancy. Part 2 Metastatic melanoma is one of the most aggressive and lethal malignancies with a poor prognosis. Melanoma cells are able to migrate using different types of cell motility such as the rounded/amoeboid-type motility and the elongated/mesenchymal-type motility thanks to their high plasticity. Really several data underline the crucial role of amoeboid motility in the dissemination process of highly metastatic melanoma cells. Thus, targeting this process could be a promising strategy to prevent the metastatic spreading of melanoma cells. Claisened Hexafluoro is a chemical analog of Honokiol (HKL), a biphenolic compound derived from Magnolia officinalis which has antitumoral and antimetastatic effect in numerous cancers, including melanoma. Starting from these evidence, here we tested Claisened Hexafluoro on human metastatic melanoma cells, as an inhibitor of amoeboid motility. Data here reported demonstrate that Claisened Hexafluoro, impairing mitochondrial activity and affecting AMP-activated protein kinase (AMPK) signaling, strongly inhibits amoeboid motility and many steps of the disseminating process in vitro as well as in vivo, confirming its possible future application to fight metastatic spreading of melanoma cells.

La transition cellulaire Mésenchymo-Amiboïde (MAT) est requise pour l'échappement métastasique, cependant elle n'a encore jamais été associée à une situation physiopathologique précise. PAI-1, l'inhibiteur de l'activateur du plasminogène de type-1, est une molécule du microenvironnement tumoral considérée comme facteur de mauvais pronostic et localisée en forte concentration autour des tumeurs les plus invasives. Nous montrons que, sous sa forme matricielle active, PAI-1 est capable d'entretenir, au cours du temps et de façon dose-dépendante, la morphologie amiboïde de cellules cancéreuses colorectales et mammaires, et que celle-ci est associée à une adhérence faible intégrines-indépendante, une migration de type amiboïde et à l'activation de la voie RhoA/ROCK-1/MLC-P. Le mécanisme moléculaire mis en jeu a partiellement été mis en évidence : nous montrons que l'immobilisation de PAI-1 et sa liaison à l'uPA sont indispensables, et nous suggérons la possibilité que le récepteur membranaire uPAR participe à la transmission de signaux maintenant la voie RhoA/ROCK-1/MLC-P active. La compatibilité des effets du PAI-1 matriciel vis-à-vis des principales voies de signalisation impliquées dans la régulation de la transition MAT est établie in silico grâce à une méthode fondée sur la modélisation de la dynamique des réseaux d'interactions. L'ensemble de ces résultats permet pour la première fois de caractériser une situation physiopathologique microenvironnementale favorable à la transition MAT ; et bien que la forme matricielle de PAI-1 n'ait pas encore livré tous ses secrets, elle semble être une cible thérapeutique intéressante.