The ETS transcription factor ETV4 is involved in the main steps of organogenesis and is also a significant mediator of tumorigenesis and metastasis, such as in breast cancer. Indeed, ETV4 is ...overexpressed in breast tumors and is associated with distant metastasis and poor prognosis. However, the cellular and molecular events regulated by this factor are still misunderstood. In mammary epithelial cells, ETV4 controls the expression of many genes, MMP13 among them. The aim of this study was to understand the function of MMP13 during ETV4-driven tumorigenesis.
Different constructs of the MMP13 gene promoter were used to study the direct regulation of MMP13 by ETV4. Moreover, cell proliferation, migration, invasion, anchorage-independent growth, and in vivo tumorigenicity were assayed using models of mammary epithelial and cancer cells in which the expression of MMP13 and/or ETV4 is modulated. Importantly, the expression of MMP13 and ETV4 messenger RNA was characterized in 456 breast cancer samples.
Our results revealed that ETV4 promotes proliferation, migration, invasion, and anchorage-independent growth of the MMT mouse mammary tumorigenic cell line. By investigating molecular events downstream of ETV4, we found that MMP13, an extracellular metalloprotease, was an ETV4 target gene. By overexpressing or repressing MMP13, we showed that this metalloprotease contributes to proliferation, migration, and anchorage-independent clonogenicity. Furthermore, we demonstrated that MMP13 inhibition disturbs proliferation, migration, and invasion induced by ETV4 and participates to ETV4-induced tumor formation in immunodeficient mice. Finally, ETV4 and MMP13 co-overexpression is associated with poor prognosis in breast cancer.
MMP13 potentiates the effects of the ETV4 oncogene during breast cancer genesis and progression.
Ets‐1 overexpression in human breast cancers is associated with invasiveness and poor prognosis. By overexpressing Ets‐1 or a dominant negative mutant in MMT breast cancer cells, we previously ...highlighted the key role of Ets‐1 in coordinating multiple invasive features of these cells. Interestingly, we also noticed that Ets‐1 decreased the density of breast cancer cells cultured in three‐dimensional extracellular matrix gels. The 3D context was instrumental to this phenomenon, as such downregulation was not observed in cells grown on two‐dimensional plastic or matrix‐coated dishes. Ets‐1 overexpression was deleterious to anchorage‐independent growth of MMT cells in soft agar, a standard model for in vitro tumorigenicity. The relevance of this mechanism was confirmed in vivo, during primary tumor growth and in a metastatic assay of lung colonization. In these models, Ets‐1 was associated with epithelial‐to‐mesenchymal transition features and modulated the ratio of Ki67‐positive cells, while hardly affecting in vivo apoptotic cell death. Finally, siRNA‐mediated knockdown of Ets‐1 in human breast cancer cell lines also decreased colony growth, both in anchorage‐independent assays and 3D extracellular matrix cultures. These in vitro and in vivo observations shed light on an unsuspected facet of Ets‐1 in breast tumorigenesis. They show that while promoting malignancy through the acquisition of invasive features, Ets‐1 also attenuates breast tumor cell growth and could therefore repress the growth of primary tumors and metastases. This work also demonstrates that 3D models may reveal mechanisms of tumor biology that are cryptic in standard 2D models.
What's New?
Overexpression of the Ets‐1 transcription factor in human breast cancers is associated with invasiveness and poor prognosis. Here the authors report the unexpected finding that Ets‐1 expression decreases cellular density when culturing breast cancer cells in three‐dimensional extracellular matrix gels. The 3D context was essential for this finding as it was not observed under 2D culturing conditions but was supported by studies in mice. This data uncovers a new dual role of Ets‐1 in tumor biology: while promoting malignant invasiveness, Ets‐1 attenuates cell growth in breast tumors as well as metastases, a new property of the proto‐oncogene with potential therapeutic implications.
The Ets family transcription factor Pea3 (ETV4) is involved in tumorigenesis especially during the metastatic process. Pea3 is known to induce migration and invasion in mammary epithelial cell model ...systems. However, the molecular pathways regulated by Pea3 are still misunderstood. In the current study, using in vivo and in vitro assays, Pea3 increased the morphogenetic and tumorigenic capacity of mammary epithelial cells by modulating their cell morphology, proliferation, and migration potential. In addition, Pea3 overexpression favored an epithelial-mesenchymal transition (EMT) triggered by TGF-β1. During investigation for molecular events downstream of Pea3, Cyclin D2 (CCND2) was identified as a new Pea3 target gene involved in the control of cellular proliferation and migration, a finding that highlights a new negative regulatory loop between Pea3 and Cyclin D2. Furthermore, Cyclin D2 expression was lost during TGF-β1-induced EMT and Pea3-induced tumorigenesis. Finally, restored Cyclin D2 expression in Pea3-dependent mammary tumorigenic cells decreased cell migration in an opposite manner to Pea3. As such, these data demonstrate that loss of the negative feedback loop between Cyclin D2 and Pea3 contributes to Pea3-induced tumorigenesis.
This study reveals molecular insight into how the Ets family transcription factor Pea3 favors EMT and contributes to tumorigenesis via a negative regulatory loop with Cyclin D2, a new Pea3 target gene.
The fusion of a wide range of proteins to the ligand-binding domain of nuclear receptors has been shown to impart ligand-dependent inducible activity of the resulting chimera. Transcriptional ...regulators of the ETS family are involved in both normal and oncogenic processes. In order to address the role of Erm, a “PEA3subgroup” member of this family, we generated a chimera between Erm and the widely used ligand-binding domain of the oestrogen receptor (ER). The chimera, ErmER, consists of Erm protein fused at its C-terminal end to the ER domain. We show that ErmER displays a ligand-dependent transcriptional activity onetsresponsive elements. The efficiency of ErmER mediated transactivation is modulated by the hormone concentration while its weak leakiness is reduced by using the steroidal anti-oestrogen EM-139. Our results define ErmER as the first conditional version of an Ets transcription factor, providing a useful tool to decipher Erm biological role and to identify potential Erm target genes.
According to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the ...10^{-15} precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives δ(Ti,Pt)=-1±9(stat)±9(syst)×10^{-15} (1σ statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations.
The MICROSCOPE mission was designed to test the weak equivalence principle (WEP), stating the equality between the inertial and the gravitational masses, with a precision of 10-15 in terms of the ...Eötvös ratio η . Its experimental test consisted of comparing the accelerations undergone by two collocated test masses of different compositions as they orbited the Earth, by measuring the electrostatic forces required to keep them in equilibrium. This was done with ultrasensitive differential electrostatic accelerometers onboard a drag-free satellite. The mission lasted two and a half years, cumulating five months worth of science free-fall data, two-thirds with a pair of test masses of different compositions—titanium and platinum alloys—and the last third with a reference pair of test masses of the same composition—platinum. We summarize the data analysis, with an emphasis on the characterization of the systematic uncertainties due to thermal instabilities and on the correction of short-lived events which could mimic a WEP violation signal. We found no violation of the WEP, with the Eötvös parameter of the titanium and platinum pair constrained to η ( Ti,Pt ) = -1.5±2.3 ( stat ) ±1.5 ( syst ) ×10-15 at 1σ in statistical errors.
Plant diversification through crop rotation or agroforestry is a promising way to improve sustainability of agroecosystems. Nonetheless, criteria to select the most suitable plant communities for ...agroecosystems diversification facing contrasting environmental constraints need to be refined. Here, we compared the impacts of 24 different plant communities on soil fertility across six tropical agroecosystems: either on highly weathered Ferralsols, with strong P limitation, or on partially weathered soils derived from volcanic material, with major N limitation. In each agroecosystem, we tested several plant communities for diversification, as compared to a matching low diversity management for their cropping system. Plant residue restitution, N, P and lignin contents were measured for each plant community. In parallel, the soil under each community was analyzed for organic C and N, inorganic N, Olsen P, soil pH and nematode community composition. Soil potential fertility was assessed with plant bioassays under greenhouse controlled climatic conditions.
Overall, plant diversification had a positive effect on soil fertility across all sites, with contrasting effects depending on soil type and legumes presence in the community. Communities with legumes improved soil fertility indicators of volcanic soils, which was demonstrated through significantly higher plant biomass production in the bioassays (+18%) and soil inorganic N (+26%) compared to the low diversity management. Contrastingly, communities without legumes were the most beneficial in Ferralsols, with increases in plant biomass production in the bioassays (+39%), soil Olsen P (+46%), soil C (+26%), and pH (+5%). Piecewise structural equation models with Shipley's test revealed that plant diversification impacts on volcanic soil fertility were related to soil N availability, driven by litter N. Meanwhile, Ferralsols fertility was related to soil P availability, driven by litter P. These findings underline the importance of multifactorial and multi-sites experiments to inform trait-based frameworks used in designing optimal plant diversification in agroecological systems.
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•We compared plant diversification impacts on soil fertility across 6 agroecosystems.•Benefits of plant diversification depended on both legume presence and soil type.•Legume-based diversification was mostly beneficial on the younger soils.•Ferralsols' fertility was improved with plant communities' litter P content.•Plant communities' traits were linked with diversification impacts on contrasting soils.
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