Carmen Mejía

Casiopeinas IIgly and IIIia Induce Apoptosis in Medulloblastoma Cells

The medulloblastoma is a tumor of the central nervous system that is expressed in childhood. Casiopeinas® are a family of molecules with an active copper 2+ core and an amino acid sequence that seem give them tumoral specificity. The mechanism of action is poorly understood; however, it has been reported that some metals such as copper and some of their complexes are toxic due to their high potential to participate in redox reactions which could cause apoptosis in medulloblastoma cells. Cell survival was measured by the MTT method and apoptosis was identified by the presence of condensed nuclei, disruption of the mitochondrial transmembrane potential, and cytoskeleton disorder. In all cases medulloblastoma cells treated with Casiopeinas showed more apoptotic features than untreated cells. Casiopeinas IIgly and IIIia promise to be important compounds for the treatment of medulloblastoma, mainly by their ability to induce apoptosis.

Whole Genome Gene Expression Analysis Reveals Casiopeína-Induced Apoptosis Pathways

Copper-based chemotherapeutic compounds Casiopeínas, have been presented as able to promote selective programmed cell death in cancer cells, thus being proper candidates for targeted cancer therapy. DNA fragmentation and apoptosis–in a process mediated by reactive oxygen species–for a number of tumor cells, have been argued to be the main mechanisms. However, a detailed functional mechanism (a model) is still to be defined and interrogated for a wide variety of cellular conditions before establishing settings and parameters needed for their wide clinical application. In order to shorten the gap in this respect, we present a model proposal centered in the role played by intrinsic (or mitochondrial) apoptosis triggered by oxidative stress caused by the chemotherapeutic agent. This model has been inferred based on genome wide expression profiling in cervix cancer (HeLa) cells, as well as statistical and computational tests, validated via functional experiments (both in the same HeLa cells and also in a Neuroblastoma model, the CHP-212 cell line) and assessed by means of data mining studies.

Expression of GABAρ subunits during rat cerebellum development

In the present study, we provide evidence for the expression of all three GABA(C) receptor rho subunits through development of the rat cerebellum. Injection of cerebellum mRNA into frog oocytes gave rise to the expression of both GABA(A) and GABA(C) receptors. qRT-PCR of RNA isolated from postnatal developing cerebella showed that the expression of each rho subunit is relatively low, with a relative comparative expression of rho3>rho1>rho2. In situ hybridization and immunohistochemistry revealed a limited distribution of GABA(C) receptors in the Purkinje and Golgi neurons whereas electron microscopy detected the rho1 and rho2 subunits in the soma and dendritic tree of the Purkinje cells. The expression of GABA(C) receptors in the cerebellum adds a new dimension to the regulation of GABAergic neurotransmission and suggests further experiments to determine their functional consequences.

Developmental expression of glycine receptor subunits in rat cerebellum

The distribution of the glycine receptor subunits α1–3 and β in the developing rat cerebellum was studied from postnatal day 1 to adulthood by means of quantitative RT‐PCR and immunohistochemistry. qRT‐PCR of postnatal cerebella indicated the presence of mRNA for each subunit, with a relative expression of α2 > α3 > α1 > β. The immunohistochemistry indicated a strong α2 signal in the Purkinje cells, internal and external granular layers. The α1–3 subunits had weak signals in the Purkinje cells and molecular layer. The α1 subunit was expressed at a low level and was also found in the white matter. The function of these receptors in neuronal and glial plasma membranes in early postnatal development remains to be determined.

Non-equilibrium thermodynamics analysis of transcriptional regulation kinetics

Abstract Gene expression in eukaryotic cells is an extremely complex and interesting phenomenon whose dynamics are controlled by a large number of subtle physicochemical processes commonly described by means of gene regulatory networks. Such networks consist in a series of coupled chemical reactions, conformational changes, and other biomolecular processes involving the interaction of the DNA molecule itself with a number of proteins usually called transcription factors as well as enzymes and other components. The kinetics behind the functioning of such gene regulatory networks are largely unknown, though its description in terms of non-equilibrium thermodynamics has been discussed recently. In this work we will derive general kinetic equations for a gene regulatory network from a non-equilibrium thermodynamical description and discuss its use in understanding the free energy constrains imposed in the network structure. We also will discuss explicit expressions for the kinetics of a simple model of gene regulation and show that the kinetic role of mRNA decay during the RNA synthesis stage (or transcription) is somehow limited due to the comparatively low values of decay rates. At the level discussed here, this implies a decoupling of the kinetics of mRNA synthesis and degradation a fact that may become quite useful when modeling gene regulatory networks from experimental data on whole genome gene expression.

Abstract CT408: Phase I study of one mixed chelates copper(II) compound, Casiopeína CasIIIia with antitumor activity and its mechanism of action

Metal complexes have gained a growing interest as pharmaceuticals for their use as diagnostic agents or as chemotherapeutic drugs[1]. In our group some efforts have been done in the development of anticancer agents employing essential metals such as the family of copper (II) compounds known as Casiopeinas®, with a general formula [Cu (N-N) (X-Y) H2O] NO3 where N-N is a diimine (phen or bipy) and X-Y is a bidentate ligand (acac, salal, aminoacidate, peptide, benzimidazol). These compounds have shown cytostatic, cytotoxic and antineoplastic activity in vitro and in vivo[2]. Also albumin/Casiopeinas interaction is discussed. Among those one have selected that is CasIII-ia as the most adequate to go into clinical trial Phase I. Although the mechanism of action is still not completely elucidated, experimental evidence suggests the interaction of coordination compounds with DNA (nuclear or mitochondrial) and their components and the generation of reactive oxygen species (ROS) as the main action pathways. Induction of apoptosis has been proved to be the main death tumoral cell pathway. DNA cleavage capacity, compared with the 4, 4´-diimine analogs, then is suggested an intercalation process as the first step for the DNA damage. Also calculations have been done in order to modeling the interaction between Casiopeinas and DNA [3, 4]. The clinical protocol phase I of the dimethyl bpy derivative with acac Cas IIIia is presented and the selection criteria of the drug. [1] S. H. van Rijt, P. J. Sadler, Drug Discov. Today, 14 (2009) 1089-1097. [2] L. Ruiz-Azuara, M.E. Bravo-Gomez, Curr. Med. Chem., 17 (2010) 3606-3615. [3] R. Galindo-Murillo, J. Hernandez-Lima, M. Gonzalez-Rendon, F. Cortes-Guzman, L. Ruiz-Azuara, R. Moreno-Esparza Phys. Chem. Chem. Phys., 13 (2011) 14511-14516. [4] R. Galindo-Murillo, L. Ruiz-Azuara, R. Moreno-Esparza, F. Cortes-Guzman Phys. Chem. Chem. Phys., 14 (2012) 15539-15546. Citation Format: Lena Ruiz-Azuara, Gerard Bastian, Maria Elena Bravo-Gomez, Roberto Carlos Canas, Marcos Flores-Alamo, Ines Fuentes, Carmen Mejia, Juan Carlos Garcia-Ramos, Alberto Serrano. Phase I study of one mixed chelates copper(II) compound, Casiopeina CasIIIia with antitumor activity and its mechanism of action. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT408. doi:10.1158/1538-7445.AM2014-CT408

Analysis of Apoptotic and Autophagic Pathways in Neuroblastoma by Treatment with Copper Compounds

Neuroblastoma (NB) is the most common extra-cranial tumor of childhood with more than 600 new cases per year in the United States. The clinical presentation is heterogeneous and dependent on age at diagnosis, staging, histology, and alterations such as MYCN amplification and chromosome 1p loss or 17q gain. High-risk patients with evidence of metastases have an overall survival rate of less than 40% despite intensive multimodality treatment. This high‐ lights the urgent need for new therapeutic intervention strategies. However due to NB characteristic molecular features, in about 10% of patients with metastases, tumors disappear by apoptosis [1].