Flunarizine as a modulator of doxorubicin resistance in human colon-adenocarcinoma cells

R. Silvestrini, N. Zaffaroni, A. Costa, L. Orlandi, R. Villa, H. R. Hendriks

Research output: Contribution to journalArticle

Abstract

The potential of the calcium-entry blocker flunarizine in modulating the cytotoxicity of doxorubicin was investigated in human colon-adenocarcinoma cell lines sensitive to (LoVo) or with experimentally induced resistance (LoVo/DX) to doxorubicin. Exposure to 1 to 2 μg/ml flunarizine for intervals of up to 24 hr did not affect cell survival in either line. Simultaneous exposure to flunarizine and doxorubicin for 1 hr selectively enhanced doxorubicin activity in the resistant cell line and not in the sensitive cell line. In particular, the doxorubicin concentration able to reduce cell survival by 50% dropped to one third. Moreover, simultaneous exposure to flunarizine significantly increased intracellular doxorubicin accumulation, as evaluated by fluorescence spectrophotometry. Again, flow-cytometric analysis showed hyperpolarization of the membrane in resistant cells, starting from 15 min of exposure to 2 μg/ml flunarizine. Finally, in LoVo/DX cells, which normally express gp170, a 24-hr treatment with flunarizine markedly reduced the immunoreactivity of cells with 2 monoclonal antibodies (MAb57 and MRK16) directed against different external epitopes of the glycoprotein. The results from our study indicate the ability of flunarizine to positively modulate doxorubicin-resistance in human colon-adenocarcinoma cells expressing the multidrug-resistance phenotype.

Original languageEnglish
Pages (from-to)636-639
Number of pages4
JournalInternational Journal of Cancer
Volume55
Issue number4
DOIs
Publication statusPublished - 1993

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Flunarizine
Doxorubicin
Colon
Adenocarcinoma
Cell Line
Cell Survival
Fluorescence Spectrometry
Multiple Drug Resistance
Epitopes
Glycoproteins
Monoclonal Antibodies
Calcium
Phenotype
Membranes

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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Flunarizine as a modulator of doxorubicin resistance in human colon-adenocarcinoma cells. / Silvestrini, R.; Zaffaroni, N.; Costa, A.; Orlandi, L.; Villa, R.; Hendriks, H. R.

In: International Journal of Cancer, Vol. 55, No. 4, 1993, p. 636-639.

Research output: Contribution to journalArticle

Silvestrini, R. ; Zaffaroni, N. ; Costa, A. ; Orlandi, L. ; Villa, R. ; Hendriks, H. R. / Flunarizine as a modulator of doxorubicin resistance in human colon-adenocarcinoma cells. In: International Journal of Cancer. 1993 ; Vol. 55, No. 4. pp. 636-639.
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AU - Villa, R.

AU - Hendriks, H. R.

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