Establishment of pemetrexed-resistant non-small cell lung cancer cell lines

Dan Zhang, Nobuaki Ochi, Nagio Takigawa, Yasushi Tanimoto, Yanyan Chen, Eiki Ichihara, Katsuyuki Hotta, Masahiro Tabata, Mitsune Tanimoto, Katsuyuki Kiura

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)

Abstract

Pemetrexed (PEM), a multitargeted antifolate with manageable toxicity, is active against non-squamous non-small cell lung cancer; however, most patients eventually acquire resistance to PEM. To elucidate the resistant mechanism, we established PEM-resistant lung adenocarcinoma cell lines. Two parental cell lines, PC-9 and A549, were treated with step-wise increasing concentrations of PEM. Growth inhibition was determined by the 3-[4,5-dimethyl-thizol-2-yl]-2,5-diphenyltetrazolium bromide assay. Expression of the genes encoding thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT) was analyzed by quantitative real-time reverse transcriptase polymerase chain reaction. The four PC-9 sublines were more resistant than the PC-9 cell line to PEM (2.2-, 2.9-, 8.4-, and 14.3-fold, respectively). The four A549 sublines also showed more resistance to PEM (7.8-, 9.6-, 42.3-, and 42.4-fold, respectively) than the parent cell line. All resistant sublines showed cross-resistance to cisplatin, but not to docetaxel, vinorelbine, 5-fluorouracil, or the active metabolite of irinotecan, SN-38. All PEM-resistant sublines expressed more TS than the parental cells, by polymerase chain reaction and Western blotting. DHFR was significantly increased in the four PEM-resistant A549 sublines. GARFT did not correlate with resistance to PEM. In summary, PEM-resistant cells remained sensitive to docetaxel, vinorelbine, 5-fluorouracil, and irinotecan. TS expression appeared to be associated with resistance to PEM.

Original languageEnglish
Pages (from-to)228-235
Number of pages8
JournalCancer Letters
Volume309
Issue number2
DOIs
Publication statusPublished - Oct 28 2011

Keywords

  • Non-small cell lung cancer
  • Pemetrexed
  • Resistance
  • Thymidylate synthase

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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