title: Functional evaluation of multidrug resistance transporter activity in surgical samples of solid tumors.
abstract: Determination of multidrug resistance (MDR) activity of tumor cells could provide important information for the personalized therapy of cancer patients. The functional calcein assay (MultiDrug Quant Assay, Solvo Biotechnology, Budaörs, Hungary) has been proven to be clinically valuable in hematological malignancies by determining the transporter activity of MDR protein 1 (MDR1, ATP-binding cassette protein [ABC] B1, P-glycoprotein-170) and MDR-related protein 1 (MRP1, ABCC1). In this study, we evaluated if the same functional test was adaptable for the analysis of MDR activity in solid tumors. For this purpose, tissue specimens of human colorectal cancer samples were subjected to limited enzymatic digestion by collagenase to provide a single-cell suspension; dead cells were excluded by 7-aminoactinomycin D staining, and epithelial cancer cells were detected by Cy5-conjugated anti-BerEP4 monoclonal antibody. The transporter functions of MDR1 and MRP1 in viable epithelial cells were assessed by flow cytometry detecting the intracellular accumulation of calcein dye after exposing cells to various MDR inhibitors. Collagenase disintegration preserved the MDR activity and the antigenicity of tumor cells. Thus using the extended calcein assay provided sufficient viable and functionally active tumor cells from surgical biopsies to determine the functional MDR activity. In conclusion, the newly described modified calcein assay may be applicable for evaluating the MDR phenotype in solid tissue specimens from colorectal forceps biopsy to surgical samples.
authors.affiliation: Rational Drug Design Laboratories CRC, Semmelweis University, Budapest, Hungary.
authors.forename: Richard
authors.initials: R
authors.lastname: Schwab
authors.forename: Tamás
authors.initials: T
authors.lastname: Micsik
authors.forename: Orsolya
authors.initials: O
authors.lastname: Szokolóczi
authors.forename: Eszter
authors.initials: E
authors.lastname: Schafer
authors.forename: Balázs
authors.initials: B
authors.lastname: Tihanyi
authors.forename: Tibor
authors.initials: T
authors.lastname: Tihanyi
authors.forename: Péter
authors.initials: P
authors.lastname: Kupcsulik
authors.forename: Katalin
authors.initials: K
authors.lastname: Diófalvi
authors.forename: Tamás
authors.initials: T
authors.lastname: Mersich
authors.forename: Istvan
authors.initials: I
authors.lastname: Besznyak
authors.forename: Attila
authors.initials: A
authors.lastname: Zarand
authors.forename: Rudolf
authors.initials: R
authors.lastname: Mihalik
authors.forename: Balázs
authors.initials: B
authors.lastname: Sarkadi
authors.forename: György
authors.initials: G
authors.lastname: Kéri
authors.forename: Akos
authors.initials: A
authors.lastname: Pap
authors.forename: Ferenc
authors.initials: F
authors.lastname: Jakab
authors.forename: László
authors.initials: L
authors.lastname: Kopper
authors.forename: Istvan
authors.initials: I
authors.lastname: Petak
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D001826:Body Fluids / Q000737:chemistry; D002277:Carcinoma / Q000737:chemistry; D002469:Cell Separation; D002470:Cell Survival; D005452:Fluoresceins / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006801:Humans; D007633:Keratins / Q000032:analysis; D007941:Leukemia P388 / Q000378:metabolism; D009369:Neoplasms / Q000737:chemistry* / Q000601:surgery*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D015415:Biomarkers; D005452:Fluoresceins; D007633:Keratins; C007740:fluorexon