Document Detail

Effect of thapsigargin on P-glycoprotein-negative and P-glycoprotein-positive L1210 mouse leukaemia cells.
MedLine Citation:
PMID:  21157003     Owner:  NLM     Status:  In-Data-Review    
Expression of drug-transporting P-glycoprotein (P-gp, an integral protein of the plasma membrane) in neoplastic cells confers multidrug resistance and also involves alteration of cell sensitivity to inhibitors of the sarco/endoplasmic reticulum calcium pump thapsigargin (Th). Mouse leukaemia L1210 cell sublines that overexpress P-gp due to selection with vincristine (R) or stable transfection with a gene encoding human P-gp (T) were less sensitive to Th than the parental cell line (S). Th at a concentration of 0.1 μmol/l did not induce alterations in the amount of P-gp mRNA in R or T cells (S cells did not contain any measurable amount of this transcript as assessed by RT-PCR) or in the amount of calnexin (CNX) or glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in all three cell sublines. However, when using a concentration of 10 μmol/l, Th decreases the amounts of CNX, GAPDH (in S, R and T cells) and P-gp (in R and T cells) mRNAs. In contrast to R and T cells (which contain abundant P-gp), S cells did not contain any P-gp detectable by the c219 antibody on a Western blot. Th at a concentration of 0.1 μmol/l induced a reduction in the amount of P-gp present in R and T cells, particularly in isoforms with higher molecular weights (i.e., mature fully glycosylated isoforms). Similar results were observed when Th was used at a concentration of 10 μmol/l. R and T cells contained lower levels of CNX than S cells. While Th at a lower concentration did not alter the levels of CNX in S, R or T cells, a higher concentration of this substance induced a measurable decrease in the amount of CNX. S, R and T cells did not differ with respect to GAPDH content, but Th induced a reduction in the amount of this protein in all cell sublines. More pronounced results were observed when Th was applied at a concentration of 10 μmol/l comparing with a concentration of 0.1 mmol/l. These changes may be involved together with the Th efflux activity of P-gp in Th-resistance associated with the P-gp-mediated multidrug resistance of R and T cells.
Mário Sereš; Peter Ditte; Albert Breier; Zdena Sulová
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  General physiology and biophysics     Volume:  29     ISSN:  0231-5882     ISO Abbreviation:  Gen. Physiol. Biophys.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8400604     Medline TA:  Gen Physiol Biophys     Country:  Slovakia    
Other Details:
Languages:  eng     Pagination:  396-401     Citation Subset:  IM    
Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovakia.
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