title: Optimized Protocol To Analyze Changes in the Lipidome of Xenografts after Treatment with 2-Hydroxyoleic Acid.
abstract: Xenografts are a popular model for the study of the action of new antitumor drugs. However, xenografts are highly heterogeneous structures, and therefore it is sometimes difficult to evaluate the effects of the compounds on tumor metabolism. In this context, imaging mass spectrometry (IMS) may yield the required information, due to its inherent characteristics of sensitivity and spatial resolution. To the best of our knowledge, there is still no clear analysis protocol to properly evaluate the changes between samples due to the treatment. Here we present a protocol for the evaluation of the effect of 2-hydroxyoleic acid (2-OHOA), an antitumor compound, on xenografts lipidome based on IMS. Direct treated/control comparison did not show conclusive results. As we will demonstrate, a more sophisticated protocol was required to evaluate these changes including the following: (1) identification of different areas in the xenograft, (2) classification of these areas (necrotic/viable) to compare similar types of tissues, (3) suppression of the effect of the variation of adduct formation between samples, and (4) normalization of the variables using the standard deviation to eliminate the excessive impact of the stronger peaks in the statistical analysis. In this way, the 36 lipid species that experienced the largest changes between treated and control were identified. Furthermore, incorporation of 2-hydroxyoleic acid to a sphinganine base was also confirmed by MS/MS. Comparison of the changes observed here with previous results obtained with different techniques demonstrates the validity of the protocol.
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) , Barrio Sarriena s/n, 48940 Leioa, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernández
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) , Barrio Sarriena s/n, 48940 Leioa, Spain.
authors.forename: Jone
authors.initials: J
authors.lastname: Garate
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) , Barrio Sarriena s/n, 48940 Leioa, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Lage
authors.affiliation: Unité de recherche Inserm 0916 , Institut Européen de Chimie et Biologie (IECB)-INSERM, 2 rue Robert Escarpit, 33607 Pessac, France.
authors.forename: Silvia
authors.initials: S
authors.lastname: Terés
authors.affiliation: Laboratory of Molecular and Cell Biomedicine, Department of Biology, University of the Balearic Islands , E-07122 Palma, Balearic Islands, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Higuera
authors.affiliation: Research Unit, Hospital Universitari Son Espases, Institut d'Investigació Sanitària de Palma (IdISPa), Carretera Valldemossa 79, E-07010 Palma, Balearic Islands, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Bestard-Escalas
authors.affiliation: Laboratory of Signal Transduction, Memorial Sloan-Kettering Cancer Center , 415 East 68th Street, New York, New York 10065, United States.
authors.forename: M Laura
authors.initials: ML
authors.lastname: Martin
authors.affiliation: Research Unit, Hospital Universitari Son Espases, Institut d'Investigació Sanitària de Palma (IdISPa), Carretera Valldemossa 79, E-07010 Palma, Balearic Islands, Spain.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: López
authors.affiliation: Laboratory of Molecular and Cell Biomedicine, Department of Biology, University of the Balearic Islands , E-07122 Palma, Balearic Islands, Spain.
authors.forename: Francisca
authors.initials: F
authors.lastname: Guardiola-Serrano
authors.affiliation: Laboratory of Molecular and Cell Biomedicine, Department of Biology, University of the Balearic Islands , E-07122 Palma, Balearic Islands, Spain.
authors.forename: Pablo V
authors.initials: PV
authors.lastname: Escribá
authors.affiliation: Research Unit, Hospital Universitari Son Espases, Institut d'Investigació Sanitària de Palma (IdISPa), Carretera Valldemossa 79, E-07010 Palma, Balearic Islands, Spain.
authors.forename: Gwendolyn
authors.initials: G
authors.lastname: Barceló-Coblijn
authors.affiliation: Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) , Barrio Sarriena s/n, 48940 Leioa, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Fernández
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D008055:Lipids / Q000032:analysis*; D013058:Mass Spectrometry; D051379:Mice; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism*; D009829:Oleic Acids / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: C483229:2-hydroxyoleic acid; D000970:Antineoplastic Agents; D008055:Lipids; D009829:Oleic Acids