CV Science

Maria Elena Fernandez Sanchez PhD Genetics

Course and current status

2015 to now  Institut Curie, Paris, France.  Chargé de Recherche INSERM. Laboratory : Physico Chimie Curie Lab, Mechanics and genetics of embryonic and tumoral development. Head : Emmanuel Farge.

 2009-2015 Institut Curie, Paris, France.  Post-doctoral researcher. Laboratory : Physico Chimie Curie Lab, Mechanics and genetics of embryonic and tumoral development. Head : Emmanuel Farge.

 2008-2009 University of Dundee, Dundee, United Kingdom. Post-doctoral Research Assistant. Laboratory : School of Life Sciences, Centre for gene regulation and expression. Head : Victoria Cowling.

 2005-2008 Institut Pasteur, Paris, France. Post-doctoral researcher. Cancéropôle, Ile de France initiative. Laboratory : Department of Immunology, Immunoregulation. Head : Lars Rogge.

 2004-2005 Centro de Investigaciones Biológicas, Madrid, Spain. Junior post-doctoral fellow. Supported by REDEMETH. Laboratory : Molecular Biomedicine, Molecular pathology/Complement Genetics.  Head : Santiago Rodriguez de Cordoba.

 2004  Ph.D. in Genetics, Centro de Investigaciones Biológicas (CIB/CSIC). Madrid, Spain.

“Molecular basis of Lafora Disease. A study of the function of the two responsible genes through the characterization of protein-protein interactions”

 2000-2004 Centro de Investigaciones Biológicas, Madrid, Spain. Pre-doctoral fellowship by the Spanish Science and Technology Ministry. Laboratory : Molecular Biomedicine, Molecular pathology/Complement Genetics.  Head : Santiago Rodriguez de Cordoba.

 1999 B.A. in Biology, Biological Science Faculty, Complutense University of Madrid, Spain.

“Establishment of phylogenetic relationships in Hordeum vulgare L. with isoenzymes, RAPDs and ISSRs”

1997-2000 Complutense University of Madrid, Spain. Undergraduate training student. Laboratoy : Faculty of Biological Science, Department of Genetics. Head : César Benito.

Scientific summary

PROJECT : Mechanical activation of the oncogenic b-catenin pathway by tumour growth pressure, in vivo.

International Context. The understanding of tumour progression has considerably advanced thanks to intensive biochemical and genetic studies of the pathways and master genes involved in the deregulation of tissue homeostasis[1]. Recently, increasing interest has focused on the role of the tumour microenvironment in tumour progression and invasion[1], with pioneer approaches having proposed a role of the rigidity of the tumour itself as an enhancer of tumour progression at late tumour stages[2, 3]. In contrast, the potential oncogenic role of the mechanical pressure developed by tumour growth applied to the non-tumorous environing epithelium have been unexplored. The testing of such mechanotransductive mechanism of amplification of tumour progression required the setting up of a new methodology allowing the application of a mechanical strain in vivo, mimicking tumour growth pressure on the weeks to months time scale. The hosting laboratory had previously found ex-vivo that pressure, potentially associated to intestinal transit or tumoral vascularization, triggers the activation of the primary b-catenin dependent oncogenic program in genetically predisposed pretumoral APC+/- mice colon tissues[4]. However, direct mechanical strains could be applied on integrated tissue only ex-vivo, on the 20 minutes time scale and with gene expression measured after 4 hours. In parallel, the hosting laboratory set-up a method of magnetic loading of early Drosophila embryos to quantitatively mimic endogenous morphogenetic movements, showing the activation of the Armadillo-β-cat/Twist pathway in vivo in the primary anterior endoderm[5, 6]. In this experiment, the time scale of the experiment was also of 20 minutes. Therefore, methods allowing the direct application of a mechanical pressure in situ on the weeks to months time scale in vivo represented one of the major challenges of such mechanotransductive approach of cancer progression, and more generally of any potential mechanotransductive dependent disease.

Objective. The aim of my project thus consisted in mimicking in vivo the mechanical pressure exerted by tumour growth on the weeks to months time scale through deep tissues stable magnetic loading and magnetic field gradient manipulation in the mouse colon, to study the consequent activation of mechanotransduction pathways leading to oncogene expression within all crypt cells in vivo.

Multidisciplinary innovative methodologies.

In vivo magnetic loading. Mice were anesthetized with isofluorane and a 3mm diameter strong magnetic field gradient magnet of 0.12T positioned subcutaneously on the back of the mice in front of the colon. The fluorescent ultra-magnetic liposomes (UML) associated with Rhodamine-PE phospholipids[7], were diluted in a citrate buffer solution to a final concentration of 0.1M and injected in the lateral caudal veins of the tail. [Collaboration with C. Ménager UMR7195-UPMC and S. Barbier in the hosting laboratory].

 Acoustic analysis of magnetically induced pressure in situ. Dissected colon samples were embedded in agar-gelatin phantoms (2%A-5%G). Ultrasound (US) images, so called B-mode and elasticity images were acquired using a high frequency US probe (15 MHz, 256 elements, Vermon, Tours-France) driven by an ultrafast imaging device (Aixplorer, Supersonic Imagine, Aix en Provence, France)[8]. Elasticity measurements, Young’s modulus (E) quantification, were performed by using the Supersonic Shear Wave Imaging (SSI) technique ex-vivo, and in vivo[9, 10]. The small magnet was axially approached towards the olon by a first step from 10 cm to 1cm, then by steps of 0.5 mm until completing 3 mm of absolute axial displacement, to reach the 7mm separating the magnet from the the colon in situ. For each position of the magnet, images of the mechanical strain induced (e) were calculated by comparing raw frequency ultrasound images acquired at two consecutive steps[11]. Cumulative strain was obtained by summing all strain images. The quantitative stress s applied by the magnetic field acting on ferrofluids trapped in colon tissues was classically retrieved by application of the elastic Hooke’s law: s=E•e[12]. [Collaboration with M. Tanter and JL. Gennisson, Inserm, U979 Langevin Institut].

Results. I have thus developed a new method allowing stable magnetization of deep tissues (colorectal conjunctive tissues) on the weeks to months time scale, by intra-venous injection of ultra-magnetic vesicles, in the presence of a strong magnetic field gradient due to a small intense magnet positioned dorsally under-skin close to the colon. Magnetic pressure quantitatively mimicked in vivo the endogenous early tumour growth stress on the order of 1200 Pa with no stiffness modification, as monitored by acoustic imaging in situ. At the molecular lever, I found that mimicking tumour growth pressure in vivo led to the phosphorylation of Ret kinase, a new putative primary mechanical sensor, in the healthy epithelium, followed by phosphorylation of b-catenin at tyrosine 654, known to impair its interaction with the E-cadherin in adherents junctions. This led to its release from the junctions to the cytoplasm and nucleus, thereby increasing nuclear translocation of b-catenin, and expression of the myc (collaboration with Sandrine Barbier in the hosting laboratory), axin-2 and zeb-1 target genes. This oncogenic mechanosensitive b-catenin pathway was revealed to be induced not only in predisposed APC+/- genetic background (after one moth), in which Anomalous Carcinoma Foci (ACFs) and tumours developed, but also in wild type (after 2 months)[13].

Conclusion: in the early stage of mouse colon tumour development, tumour growth pressure activates the oncogenic mechanosensitive b-catenin pathway in the mechanically stressed non-tumorous epithelial cells in vivo. This mechanical activation of the oncogenic b-catenin pathway thus suggests the existence of new modes of tumour propagation based on mechanical induction of oncogenic pathways in healthy epithelial cells by tumour growth pressure.

1.   Hanahan, D. and R.A. Weinberg, Hallmarks of Cancer: The Next Generation. Cell, 2011. 144(5):646-674.

2.   Butcher, D.T., T. Alliston, and V.M. Weaver, A tense situation: forcing tumour progression. Nature Reviews Cancer, 2009. 9(2):108-122.

3.   Wozniak, M.A. and C.S. Chen, Mechanotransduction in development: a growing role for contractility. Nature Reviews Molecular Cell Biology, 2009. 10(1):34-43.

4.   Whitehead, J., et al., Mechanical factors activate beta-catenin-dependent oncogene expression in APC(1638N/+) mouse colon. Hfsp Journal, 2008. 2(5):286-294.

5.   Farge, E., Mechanical induction of twist in the Drosophila foregut/stomodeal primordium. Current Biology, 2003. 13(16):1365-1377.

6.   Desprat, N., et al., Tissue deformation modulates twist expression to determine anterior midgut differentiation in Drosophila embryos. Developmental Cell, 2008. 15(3):470-477.

7.   Béalle, G., et al., Ultra Magnetic Liposomes for MR Imaging, Targeting, and Hyperthermia. Langmuir, 2012. 28(32):11843-11851.

8.   Chamming's, F.L.-O., H., Lefrère-Belda, M.A., Fitoussi, V., Quibel, T., Assayg, F., Marangoni, E., Autret, G., Balvay, L., Pidial, L., Gennisson, J.L., Tanter, M., Cuenod, C.A., Clément, O., Fournier, L., Shear wave elastography of tumor growth in a human breast cancer model with pathological correlation. Europ. Radiol, 2013.

9.   Bercoff, J., M. Tanter, and M. Fink, Supersonic shear imaging: A new technique for soft tissue elasticity mapping. IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2004. 51(4):396-409.

10. Sarvazyan, A.P., et al., Shear wave elasticity imaging: A new ultrasonic technology of medical diagnostics. Ultrasound in Medicine and Biology, 1998. 24(9):1419-1435.

11. Ophir, J., et al., Elastography - a Quantitative Method for Imaging the Elasticity of Biological Tissues. Ultrasonic Imaging, 1991. 13(2):111-134.

12. Latorre-Ossa, H., et al., Quantitative Imaging of Nonlinear Shear Modulus by Combining Static Elastography and Shear Wave Elastography. IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2012. 59(4):833-839.

13. Fernandez-Sanchez, M.E., et al., Mechanical induction of the tumourogenic b-catenin pathway by tumour growth pressure. Nature, 2015. 5523(7558):92-95.