title: In vitro chemosensitivity of canine mast cell tumors grades II and III to all-trans-retinoic acid (ATRA).
abstract: Mast cell tumor (MCT) is one of the most prevalent neoplasms that affect the skin and soft tissue of dogs. Because mast cell tumors present a great variety of clinical appearance and behavior, their treatment becomes a challenge. While retinoids are well recognized as promising antitumor agents, there have been only a few reports about retinoids' effect on canine cancers. The aim of this study was to investigate the chemosensitivity of MCT grades II and III to all-trans retinoic acid (ATRA). Immediately after surgical resection, MCT were prepared for primary culture. Samples of MCTs were also fixed in formalin for histopathology and grading according to the classification of Patnaik et al. (Veterinary Pathology 21(5):469-474, 1984). The best results were obtained when neoplastic mast cells were co-cultivated with fibroblasts. Cultured mast cells were, then, treated with concentrations of 10(-4) to 10(-7) M of ATRA, in order to evaluate their chemosensitivity to this retinoid. MTT assay was performed to estimate cell growth and death. The highest level of mast cell chemosensivity was obtained at the dose of 10(-4) M (p < 0,002). MCT of grades II or III were equally susceptible to the treatment with ATRA. Cell death was observed on the first 24 h until 48 h. According to these results, ATRA may be a potential chemotherapeutic agent for the treatment of canine MCT.
authors.affiliation: Laboratory of Experimental Oncology, Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: K C
authors.initials: KC
authors.lastname: Pinello
authors.forename: M
authors.initials: M
authors.lastname: Nagamine
authors.forename: T C
authors.initials: TC
authors.lastname: Silva
authors.forename: P
authors.initials: P
authors.lastname: Matsuzaki
authors.forename: H V
authors.initials: HV
authors.lastname: Caetano
authors.forename: L N
authors.initials: LN
authors.lastname: Torres
authors.forename: H
authors.initials: H
authors.lastname: Fukumasu
authors.forename: J L
authors.initials: JL
authors.lastname: Avanzo
authors.forename: J M
authors.initials: JM
authors.lastname: Matera
authors.forename: M L Z
authors.initials: ML
authors.lastname: Dagli
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004283:Dog Diseases / Q000188:drug therapy* / Q000473:pathology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008407:Mast Cells / Q000473:pathology*; D008415:Mastocytosis / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D013778:Tetrazolium Salts / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry; D014212:Tretinoin / Q000008:administration & dosage / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D014212:Tretinoin; C022616:thiazolyl blue