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Doxorubicin-resistant, MRP1-expressing U-1285 cells are sensitive to idarubicin

Kerstin Jönsson-Videsäter1, Göran Andersson, Jonas Bergh

  • 1Department of Medicine, Huddinge University Hospital, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.

Insights

A new doxorubicin-resistant lung cancer cell line (U-1285dox(900)) shows elevated MRP1 expression, conferring resistance to several chemotherapy drugs. This resistance can be reversed by specific agents, offering potential therapeutic insights.

Area of Science:

  • * Molecular oncology
  • * Cancer cell biology
  • * Drug resistance mechanisms

Background:

  • * Small cell lung carcinoma (SCLC) is an aggressive cancer with limited treatment options.
  • * Acquired resistance to chemotherapy is a major challenge in SCLC treatment.
  • * Multidrug resistance protein 1 (MRP1) is implicated in cellular drug efflux and resistance.

Purpose of the Study:

  • * To characterize the resistance profile of a novel doxorubicin-resistant SCLC subline (U-1285dox(900)).
  • * To investigate the role of MRP1 in the observed drug resistance.
  • * To explore potential strategies for reversing chemoresistance.

Main Methods:

  • * Derivation of a doxorubicin-resistant subline (U-1285dox(900)) from the parental U-1285 SCLC cell line.
  • * Quantification of MRP1 and MDR1 mRNA using reverse transcriptase-polymerase chain reaction (RT-PCR).
  • * Analysis of MRP1 and P-glycoprotein expression via Western blot.
  • * Assessment of drug resistance profiles and collateral sensitivity.
  • * Evaluation of resistance reversal using buthionine-sulphoximine and verapamil.

Main Results:

  • * U-1285dox(900) cells exhibited significantly elevated MRP1 mRNA and protein levels compared to parental cells.
  • * No detectable MDR1 mRNA or P-glycoprotein was found in either cell line.
  • * The resistant subline showed high resistance to doxorubicin, epirubicin, daunorubicin, and vincristine, with intermediate resistance to mitoxantrone and low resistance to etoposide.
  • * Collateral sensitivity was observed for cytosine arabinoside, chlorodeoxyadenosine, and melphalan.
  • * Buthionine-sulphoximine and verapamil effectively reversed resistance to all tested drugs.
  • * Idarubicin accumulation was higher due to slower transport in U-1285dox(900) cells, correlating with lower resistance compared to daunorubicin.

Conclusions:

  • * MRP1 overexpression is a key mechanism of doxorubicin resistance in the U-1285 SCLC subline.
  • * The U-1285dox(900) model provides a valuable tool for studying MRP1-mediated drug resistance in SCLC.
  • * Targeting MRP1 or using combination therapies with resistance modulators may overcome chemoresistance in SCLC.

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