• Structure and molecular characterization of cytoskeleton proteins, genes and functions.
• Cytoskeleton organization and modulation of signaling pathways during epithelial-mesenchymal transition in cancer cells and during host-parasite interactions.

Eukaryotic cells, in both unicellular and pluricellular organisms, have a defined morphology and internal organization. However, cells need enough plasticity to change shape, to divide, spread and migrate to adapt to changes in their microenvironment. All these functions depend on the organization of filamentous and tubular structures that constitute the cell cytoskeleton.

Endothelial and epithelial cells form protective barriers in the tissues to prevent entrance of pathogens and foreign molecules into internal organs. To perform the barrier function these cells have a well organized cytoskeleton in close contact with the external cell membrane. In particular, actin filaments, a main component of the cytoskeleton, and its associated proteins play an important role to maintain the intercellular junctions that form the barrier.

We have characterized proteins that associate with components of the intercellular junctions, among them actin and myosin and membrane receptors with the capacity to convey signals to the interior of the cells; where diverse chains of chemical reactions take place for proper cellular function.

In my laboratory, we have being studying for several years many of the components of the cytoskeleton, employing different cell systems. We have analyzed how the cytoskeleton regulates cell locomotion and spreading, tissue permeability, phagocytosis, adhesion, secretion and cytoplasmic organelle traffic. All these functions have in common that they are activated by external signals that when transduced into the cells activate cascades of chemical reactions. These cascades, also called signaling pathways, can modulate the organization of the cytoskeleton as well as modify protein activities, gene expression and the movement of molecules into different cell compartments.

At this time, we are studying the role of the cytoskeleton in the parasite of humans Entamoeba histolytica when the amebas interact with cells from the human colon epithelium during an infection. We are also studying how the cytoskeleton modulates the changes in shape, movements and metabolism observed in non-invasive cancer cells that induce signaling pathways activated during their transition to invasiveness in an inflammatory milieu.

How the cytoskeleton is organized in olfactory neurons of psychiatric patients and how changes in its organization and in the activation of signaling pathways are involved in their functions, is another interesting study that we have recently approached.

Some of our publications below show the results obtained recently along our research lines.

Pérez-Yepez EA, Ayala-Sumuano JT, Lezama R, Meza I. (2014). A novel β-catenin signaling pathway activated by IL-β leads to the onset of epithelial mesenchymal transition in breast cancer cells. Cancer Letters, Sept.2-14. DOI 10.1016/j.canlet.2014.08.015.

Ayala-Sumuano JT, Téllez-López VM, Domínguez-Robles MC, Shibayama-Salas M, Meza I. (2013) Toll- Like Receptor Signaling Activation by Entamoeba histolytica induces Beta Defensin 2 in Human Colonic Ephitelial Cells: Its Possible Role as an Element of the Innate Immune Response, PLOS Neglected Tropical Diseases, Volumen 7, February, Issue 2 e 2083.

Eloy Andrés Pérez-Yépez, Jorge-Tonatiuh, Ayala-Sumuano, Alicia María Reveles-Espinoza and Isaura Meza. (2012). Selection of a MCF-7 Breast Cancer Cell Subpopulation with High Sensitivity to IL-1β: Characterization of and Correlation between Morphological and Molecular Changes Leading to Increased Invasiveness. International Journal of Breast Cancer, Article ID 609148, 12 pages, doi:10.1155/2012/609148

Isaura Meza, J. Daniel Díaz-Valencia, Elizabeth Franco, Nicolás Villegas-Sepúlveda, Ruth A. Lezama, Gloria Benítez-King. (2012). Molecular and functional characterization of an Entamoeba histolytica protein (EhMLCI) with features of a myosin essential light chain. Molecular & Biochemical Parasitology 181: 17– 28 0166- Elsevier B.V. All rights reserved. doi:10.1016/j.molbiopara..09.007

J. Pacheco-Yepez, J. M. Galván-Moroyoqui, I. Meza, V. Tsutsumi and M. Shibayama, (2011). Expression of cytokines and their regulation during amoebic liver abscess development, Parasite Immunology, 33:56-64, doi:10.1111/j.1365-3024..01252.x

Galván-Moroyoqui JM, Domínguez-Robles MC, Meza I.(2011).Pathogenic bacteria prime the induction of Toll-like receptor signalling in human colonic cells by the Gal/GalNAclectin Carbohydrate Recognition Domain of Entamoeba histolytica. Int J Parasitol. 2011 Aug 15;41(10):1101-12. Epub  Jul 13. PubMed PMID: 21787776

Franco-Barraza J, Valdivia-Silva JE, Zamudio-Meza H, Castillo A, García-Zepeda EA, Benítez-Bribiesca L, Meza I.(2010).Actin cytoskeleton participation in the onset of IL-1beta induction of an invasive mesenchymal-like phenotype in epithelial MCF-7 cells. Arch Med Res. Apr;41(3):170-81. PubMed PMID: 20682174

Zamudio-Meza H, Castillo-Alvarez A, González-Bonilla C, Meza I. (2009).Cross-talk between Rac1 and Cdc42 GTPases regulates formation of filopodia required for dengue virus type-2 entry into HMEC-1 cells. J Gen Virol. Dec;90 (Pt 12):2902-11. Epub  Aug 26. PubMed PMID: 19710257