Osteosarcoma cells, resistant to methotrexate due to nucleoside and nucleobase salvage, are sensitive to nucleoside analogs

Peter D. Cole, Angela K. Smith, Barton A. Kamen

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Purpose: To test a novel strategy for overcoming intrinsic resistance to methotrexate (MTX) in osteosarcoma (OS) due to nucleoside and nucleobase salvage (NS). Methods: Four OS cell lines, found to be highly resistant to MTX, were tested to determine the dominant mechanism of resistance. Sensitivity to MTX was tested in the presence of dialyzed serum or the transport inhibitor dipyridamole (DP) to confirm the contribution of NS to MTX resistance. We then investigated whether increased NS activity could be exploited using cytotoxic nucleoside analogs. Results: Like other cell types, OS cells are capable of circumventing inhibition of de novo nucleotide synthesis by relying on NS. MTX, at concentrations as high as 1 mM did not inhibit cell growth in culture medium supplemented with undialyzed serum. In contrast, when NS was inhibited by DP or in medium depleted of nucleosides and nucleobases, sensitivity to MTX was seen at nanomolar concentrations. In medium with dialyzed serum, thymidine and hypoxanthine provided dose-dependent protection from MTX toxicity at concentrations similar to those seen in human plasma. No evidence of other significant mechanisms of resistance were found. All four cell lines were sensitive to 3-day exposures to cytarabine (IC50 0.22 to 2.88 μM) and vidarabine (IC50 0.09 to 0.95 μM). Conclusions: Salvage of de novo nucleotide synthesis inhibition by extracellular thymidine and hypoxanthine, at physiologically relevant concentrations, contributes to resistance to MTX in OS. However, this same process may impart a collateral sensitivity to nucleoside analogs. These findings support clinical trials for patients with OS using nucleoside analogs, either alone or in combination.

Original languageEnglish (US)
Pages (from-to)111-116
Number of pages6
JournalCancer Chemotherapy and Pharmacology
Volume50
Issue number2
DOIs
StatePublished - 2002
Externally publishedYes

Fingerprint

Salvaging
Osteosarcoma
Nucleosides
Methotrexate
Hypoxanthine
Dipyridamole
Thymidine
Inhibitory Concentration 50
Nucleotides
Serum
Cells
Vidarabine
Plasma (human)
Cell Line
Cytarabine
Cell growth
Toxicity
Culture Media
Clinical Trials
Growth

Keywords

  • Ara-A
  • Ara-C
  • Drug resistance
  • Methotrexate
  • Osteosarcoma

ASJC Scopus subject areas

  • Cancer Research
  • Pharmacology
  • Oncology

Cite this

Osteosarcoma cells, resistant to methotrexate due to nucleoside and nucleobase salvage, are sensitive to nucleoside analogs. / Cole, Peter D.; Smith, Angela K.; Kamen, Barton A.

In: Cancer Chemotherapy and Pharmacology, Vol. 50, No. 2, 2002, p. 111-116.

Research output: Contribution to journalArticle

@article{3388258408ff45a3b1f59ca98f1b4f2e,
title = "Osteosarcoma cells, resistant to methotrexate due to nucleoside and nucleobase salvage, are sensitive to nucleoside analogs",
abstract = "Purpose: To test a novel strategy for overcoming intrinsic resistance to methotrexate (MTX) in osteosarcoma (OS) due to nucleoside and nucleobase salvage (NS). Methods: Four OS cell lines, found to be highly resistant to MTX, were tested to determine the dominant mechanism of resistance. Sensitivity to MTX was tested in the presence of dialyzed serum or the transport inhibitor dipyridamole (DP) to confirm the contribution of NS to MTX resistance. We then investigated whether increased NS activity could be exploited using cytotoxic nucleoside analogs. Results: Like other cell types, OS cells are capable of circumventing inhibition of de novo nucleotide synthesis by relying on NS. MTX, at concentrations as high as 1 mM did not inhibit cell growth in culture medium supplemented with undialyzed serum. In contrast, when NS was inhibited by DP or in medium depleted of nucleosides and nucleobases, sensitivity to MTX was seen at nanomolar concentrations. In medium with dialyzed serum, thymidine and hypoxanthine provided dose-dependent protection from MTX toxicity at concentrations similar to those seen in human plasma. No evidence of other significant mechanisms of resistance were found. All four cell lines were sensitive to 3-day exposures to cytarabine (IC50 0.22 to 2.88 μM) and vidarabine (IC50 0.09 to 0.95 μM). Conclusions: Salvage of de novo nucleotide synthesis inhibition by extracellular thymidine and hypoxanthine, at physiologically relevant concentrations, contributes to resistance to MTX in OS. However, this same process may impart a collateral sensitivity to nucleoside analogs. These findings support clinical trials for patients with OS using nucleoside analogs, either alone or in combination.",
keywords = "Ara-A, Ara-C, Drug resistance, Methotrexate, Osteosarcoma",
author = "Cole, {Peter D.} and Smith, {Angela K.} and Kamen, {Barton A.}",
year = "2002",
doi = "10.1007/s00280-002-0478-7",
language = "English (US)",
volume = "50",
pages = "111--116",
journal = "Cancer Chemotherapy and Pharmacology",
issn = "0344-5704",
publisher = "Springer Verlag",
number = "2",

}

TY - JOUR

T1 - Osteosarcoma cells, resistant to methotrexate due to nucleoside and nucleobase salvage, are sensitive to nucleoside analogs

AU - Cole, Peter D.

AU - Smith, Angela K.

AU - Kamen, Barton A.

PY - 2002

Y1 - 2002

N2 - Purpose: To test a novel strategy for overcoming intrinsic resistance to methotrexate (MTX) in osteosarcoma (OS) due to nucleoside and nucleobase salvage (NS). Methods: Four OS cell lines, found to be highly resistant to MTX, were tested to determine the dominant mechanism of resistance. Sensitivity to MTX was tested in the presence of dialyzed serum or the transport inhibitor dipyridamole (DP) to confirm the contribution of NS to MTX resistance. We then investigated whether increased NS activity could be exploited using cytotoxic nucleoside analogs. Results: Like other cell types, OS cells are capable of circumventing inhibition of de novo nucleotide synthesis by relying on NS. MTX, at concentrations as high as 1 mM did not inhibit cell growth in culture medium supplemented with undialyzed serum. In contrast, when NS was inhibited by DP or in medium depleted of nucleosides and nucleobases, sensitivity to MTX was seen at nanomolar concentrations. In medium with dialyzed serum, thymidine and hypoxanthine provided dose-dependent protection from MTX toxicity at concentrations similar to those seen in human plasma. No evidence of other significant mechanisms of resistance were found. All four cell lines were sensitive to 3-day exposures to cytarabine (IC50 0.22 to 2.88 μM) and vidarabine (IC50 0.09 to 0.95 μM). Conclusions: Salvage of de novo nucleotide synthesis inhibition by extracellular thymidine and hypoxanthine, at physiologically relevant concentrations, contributes to resistance to MTX in OS. However, this same process may impart a collateral sensitivity to nucleoside analogs. These findings support clinical trials for patients with OS using nucleoside analogs, either alone or in combination.

AB - Purpose: To test a novel strategy for overcoming intrinsic resistance to methotrexate (MTX) in osteosarcoma (OS) due to nucleoside and nucleobase salvage (NS). Methods: Four OS cell lines, found to be highly resistant to MTX, were tested to determine the dominant mechanism of resistance. Sensitivity to MTX was tested in the presence of dialyzed serum or the transport inhibitor dipyridamole (DP) to confirm the contribution of NS to MTX resistance. We then investigated whether increased NS activity could be exploited using cytotoxic nucleoside analogs. Results: Like other cell types, OS cells are capable of circumventing inhibition of de novo nucleotide synthesis by relying on NS. MTX, at concentrations as high as 1 mM did not inhibit cell growth in culture medium supplemented with undialyzed serum. In contrast, when NS was inhibited by DP or in medium depleted of nucleosides and nucleobases, sensitivity to MTX was seen at nanomolar concentrations. In medium with dialyzed serum, thymidine and hypoxanthine provided dose-dependent protection from MTX toxicity at concentrations similar to those seen in human plasma. No evidence of other significant mechanisms of resistance were found. All four cell lines were sensitive to 3-day exposures to cytarabine (IC50 0.22 to 2.88 μM) and vidarabine (IC50 0.09 to 0.95 μM). Conclusions: Salvage of de novo nucleotide synthesis inhibition by extracellular thymidine and hypoxanthine, at physiologically relevant concentrations, contributes to resistance to MTX in OS. However, this same process may impart a collateral sensitivity to nucleoside analogs. These findings support clinical trials for patients with OS using nucleoside analogs, either alone or in combination.

KW - Ara-A

KW - Ara-C

KW - Drug resistance

KW - Methotrexate

KW - Osteosarcoma

UR - http://www.scopus.com/inward/record.url?scp=0036353412&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036353412&partnerID=8YFLogxK

U2 - 10.1007/s00280-002-0478-7

DO - 10.1007/s00280-002-0478-7

M3 - Article

VL - 50

SP - 111

EP - 116

JO - Cancer Chemotherapy and Pharmacology

JF - Cancer Chemotherapy and Pharmacology

SN - 0344-5704

IS - 2

ER -