Combined epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor and chemotherapy in non-small-cell lung cancer: Chemo-refractoriness of cells harboring sensitizing-EGFR mutations in the presence of gefitinib

Chun Ming Tsai, Jen Ting Chen, Chao Hua Chiu, Chun Liang Lai, Shih Yin Hsiao, Kuo Ting Chang

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Background: Combined epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) with chemotherapy is believed to be more effective in treating non-small-cell lung cancer (NSCLC) with sensitizing-EGFR mutation (SEM). This hypothesis failed to be realized clinically and needs to be examined in vitro. Materials and methods: Using the tetrazolium colorimetric assay and classical isobole method, we investigated the combination effects of 6 gefitinib-chemotherapeutic doublets (gefitinib/cisplatin, gemcitabine, pemetrexed, paclitaxel, docetaxel, or vinorelbine) in a panel of 15 NSCLC cell lines. Results: Upon treatment with the 6 gefitinib-chemotherapeutic doublets, the 12 cell lines that did not harbor SEM displayed a broad spectrum of group results, from obvious synergism to robust antagonism. The values of group mean combination index (mCIs) ranged from 0.769 to 1.201. In contrast, the 3 cell lines with SEM showed a tendency toward consistent antagonism to the tested doublets, impressively, with a narrow range of higher group mCIs (0.993-1.141). In the presence of gefitinib, the SEM or gefitinib-sensitive group was more chemo-refractory than the non-SEM (index of chemo-refractoriness (RI): 69.33 versus 42.67; P= 0.036) or gefitinib-resistant group (68.25 versus 40.64, P= 0.0108), respectively. The results of using the gefitinib/drug combinations with the gefitinib-sensitive non-SEM cell line H322 and the gefitinib-resistant EGFR mutant H820 shared patterns similar to those with the SEM and non-SEM cell lines, respectively. Conclusion: Gefitinib-treated EGFR-TKI-sensitive NSCLC cells showed a wide spectrum of chemo-refractoriness, suggesting that concomitantly combined EGFR-TKI-chemotherapy might not be a good treatment strategy for NSCLC harboring SEM.

Original languageEnglish (US)
Pages (from-to)305-312
Number of pages8
JournalLung Cancer
Volume82
Issue number2
DOIs
StatePublished - Nov 1 2013
Externally publishedYes

Keywords

  • Combination therapy
  • EGFR mutation
  • Epidermal growth factor receptor (EGFR)
  • Non-small-cell lung cancer (NSCLC)
  • Tyrosine kinase inhibitor (TKI)

ASJC Scopus subject areas

  • Oncology
  • Pulmonary and Respiratory Medicine
  • Cancer Research

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