Genomic imbalances associated with methotrexaate resistance in human osteosarcoma cell lines detected by comparative genomic hybridization-based techniques

Claudia M. Hattinger, Gemma Reverter-Branchat, Daniel Remondini, Gastone C. Castellani, Stefania Benini, Michela Pasello, Maria C. Manara, Katia Scotlandi, Piero Picci, Massimo Serra

Research output: Contribution to journalArticlepeer-review

Abstract

Methotrexate (MTX) is one of the most important drugs for osteosarcoma (OS) treatment. To identify genetic aberrations associated with the development of MTX resistance in OS cells, in addition to the previously reported expression changes of dihydrofolate reductase (DHFR) and reduced folate carrier (RFC) genes, comparative genomic hybridization (CGH)-based techniques were used. The direct comparison between MTX-resistant variants of U-2OS or Saos-2 human OS cell lines with their respective parental cell lines by CGH on chromosomes revealed that development of MTX resistance was associated with gain of the chromosomal regions 5q12-q15 and 11q14-qter in U-2OS variants, and with gain of 8q22-qter in Saos-2 variants. Further analyses by CGH on microarrays demonstrated a progressively increasing gain of mixed lineage leukemia (MLL) gene (11q23) in U-2OS MTX-resistant variants, which was also confirmed by fluorescence in situ hybridization (FISH), in addition to gain of FGR (1p36), amplification/overexpression of DHFR, and slight decrease of RFC expression. In Saos-2 MTX-resistant variants, gain of MYC (8q24.12-q24.13) was detected, together with a remarkable decrease of RFC expression. Further analyses of DHFR, MLL, MYC, and RFC gene status in four additional human OS cell lines revealed that only gain of DHFR and MLL were associated with an inherent lower sensitivity to MTX. These data demonstrate that genetic analyses with complementary techniques are helpful for the identification of new candidate genes, which might be considered for an early identification of MTX unresponsive tumors.

Original languageEnglish
Pages (from-to)483-493
Number of pages11
JournalEuropean Journal of Cell Biology
Volume82
Issue number9
DOIs
Publication statusPublished - Sep 1 2003

Keywords

  • Comparative genomic hybridization
  • Fluorescence in situ hybridization
  • Methotrexate resistance
  • Microarray
  • Osteosarcoma

ASJC Scopus subject areas

  • Anatomy
  • Cell Biology

Fingerprint

Dive into the research topics of 'Genomic imbalances associated with methotrexaate resistance in human osteosarcoma cell lines detected by comparative genomic hybridization-based techniques'. Together they form a unique fingerprint.

Cite this