Pre-treatment of human osteosarcoma cells with N-methylformamide enhances P-glycoprotein expression and resistance to doxorubicin

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N-methylformamide (NMF), a powerful differentiating agent, has been extensively used in experimental and preclinical cancer chemotherapy studies, alone or in association with conventional anti-cancer drugs. To evaluate the use of this molecule in the treatment of osteosarcoma (OS), we have analyzed the effects of NMF and doxorubicin (DXR) on DXR-sensitive and -resistant human OS cell lines. Our study shows that NMF exerts remarkable effects on cell proliferation and, in Saos-2 and SARG cells, also induces differentiation, as shown by increasing alkaline phosphatase activity. Moreover, NMF increases the cytotoxic activity of DXR when administered after the drug, in both DXR-sensitive and -resistant cells. However, when this agent is given before DXR, it enhances P-glycoprotein expression in U-2 OS cell lines. This over-expression is associated with reduced DXR accumulation within cells and with significant enhancement of resistance to DXR.

Original languageEnglish
Pages (from-to)95-101
Number of pages7
JournalInternational Journal of Cancer
Issue number1
Publication statusPublished - 1994


ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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