title: Isolation and characterization of squamous carcinoma cells resistant to photodynamic therapy.
abstract: Photodynamic therapy (PDT) employing methyl δ-aminolevulinic acid (Me-ALA), as a precursor of the photosensitizer protoporphyrin IX (PpIX), is used for the treatment of non melanoma cutaneous cancer (NMCC). However, one of the problems of PDT is the apparition of resistant cell populations. The aim of this study was to isolate and characterize squamous carcinoma cells SCC-13 resistant to PDT with Me-ALA. The SCC-13 parental population was submitted to successive cycles of Me-ALA-PDT and 10 resistant populations were finally obtained. In parental and resistant cells there were analyzed the cell morphology (toluidine blue), the intracellular PpIX content (flow cytometry) and its localization (fluorescence microscopy), the capacity of closing wounds (scratch wound assay), the expression of cell-cell adhesion proteins (E-cadherin and β-catenin), cell-substrate adhesion proteins (β1-integrin, vinculin and phospho-FAK), cytoskeleton proteins (α-tubulin and F-actin) and the inhibitor of apoptosis protein survivin, in the activated form as phospho-survivin (indirect immunofluorescence and Western blot). The results obtained indicate that resistant cells showed a more fibroblastic morphology, few differences in intracellular content of the photosensitizer, higher capacity of closing wounds, higher number of stress fibers, more expression of cell-substrate adhesion proteins and higher expression of phospho-survivin than parental cells. These distinctive features of the resistant cells can provide decisive information to enhance the efficacy of Me-ALA applications in clinic dermatology.
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto 5800, Córdoba, Argentine. lmilla@exa.unrc.edu.ar
authors.forename: Laura N
authors.initials: LN
authors.lastname: Milla
authors.forename: Ingrid S
authors.initials: IS
authors.lastname: Cogno
authors.forename: Matías E
authors.initials: ME
authors.lastname: Rodríguez
authors.forename: Francisco
authors.initials: F
authors.lastname: Sanz-Rodríguez
authors.forename: Alicia
authors.initials: A
authors.lastname: Zamarrón
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Gilaberte
authors.forename: Elisa
authors.initials: E
authors.lastname: Carrasco
authors.forename: Viviana A
authors.initials: VA
authors.lastname: Rivarola
authors.forename: Angeles
authors.initials: A
authors.lastname: Juarranz
mesh_terms: D000622:Aminolevulinic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D015820:Cadherins / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D045744:Cell Line, Tumor / Q000187:drug effects / Q000528:radiation effects; D002465:Cell Movement / Q000187:drug effects / Q000528:radiation effects; D053144:Cell Nucleus Shape; D048430:Cell Shape; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003598:Cytoskeletal Proteins / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D044767:Ubiquitin-Protein Ligases; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D051034:Inhibitor of Apoptosis Proteins; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D051176:beta Catenin; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX; C494833:BIRC2 protein, human; D044767:Ubiquitin-Protein Ligases