title: Expression of P-glycoprotein in L1210 cells is linked with rise in sensitivity to Ca2+.
abstract: L1210/VCR cell line (R) was obtained by adaptation of the L1210 mouse leukaemia cells (S) to vincristine and showed P-glycoprotein (P-gp) mediated multidrug resistance (MDR). R cells were observed to be more sensitive to high external calcium as parental S. More pronounced calcium uptake was observed for R cells. Moreover, differences in intracellular calcium cell localization between S and R cells were found ultrastructurally following a calcium precipitating cytochemical method. In S cells, calcium precipitates were found to be localized predominantly along the cell surface coat and within mitochondria delineating the cristae. In R cells, precipitates were also found inside nuclei, at the border of heterochromatin clumps, and scattered within the cytoplasm. High extracellular calcium did not influence the P-gp mediated extrusion of calcein/AM as P-gp substrate. These results indicate that calcium enters and consequently damages the MDR cells to a higher extent than parental cells.
authors.affiliation: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovakia.
authors.forename: Zdena
authors.initials: Z
authors.lastname: Sulová
authors.forename: Jozef
authors.initials: J
authors.lastname: Orlický
authors.forename: Roderik
authors.initials: R
authors.lastname: Fiala
authors.forename: Ima
authors.initials: I
authors.lastname: Dovinová
authors.forename: Branislav
authors.initials: B
authors.lastname: Uhrík
authors.forename: Mário
authors.initials: M
authors.lastname: Seres
authors.forename: Lenka
authors.initials: L
authors.lastname: Gibalová
authors.forename: Albert
authors.initials: A
authors.lastname: Breier
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D005444:Flunarizine / Q000494:pharmacology; D007939:Leukemia L1210 / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D014700:Verapamil / Q000494:pharmacology; D014750:Vincristine / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D002121:Calcium Channel Blockers; D014750:Vincristine; D000255:Adenosine Triphosphate; D014700:Verapamil; D005444:Flunarizine; D002118:Calcium