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Y.J. Choi



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    P1.05 - Poster Session 1 - Preclinical Models of Therapeutics/Imaging (ID 156)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P1.05-008 - The HSP 90 inhibitors suppress cell growth by suppression of ALK and TGF-beta1 signaling in crizotinib-resitant H2228 cells by Epithelial to mesenchymal transition (ID 2544)

      09:30 - 09:30  |  Author(s): Y.J. Choi

      • Abstract

      Background
      Epithelial to mesenchymal transition (EMT) is related with reduced sensitivity to many chemotherapeutic drugs including EGFR tyrosine kinase inhibitors. We investigated whether EMT also could contribute to the resistance to crizotinib and there are other therapeutic options overcoming EMT-mediated resistance.

      Methods
      We established a crizotinib-resistant subline (H2228/CR), which was derived from the parental H2228 cell line by long-term exposure to increasing concentration of crizotinib. Characteristics related with EMT including morphology, EMT marker proteins and cellular mobility were analyzed. We examined whether the induction of EMT affect sensitivity to Hsp90 inhibitors.

      Results
      Compared with the H2228 cell, the growth of H2228/CR cells was independent on EML4-ALK, and they showed cross-resistance to TAE-684 (a 2[nd]-generation ALK inhibitor). Phenotypic change of a spindle-cell shape was found in H2228/CR, which was accompanied by a decrease of E-cadherin and an increase of vimentin and AXL. In addition, they showed the increased secretion and expression of TGF-β1. The capability of invasion and migration was dramatically increased in H2228/CR cells. TGF-b1 treatment for 72 h in parental H2228 cells induced reversible EMT leading to crizotinib-resistance while this was reversed through the removal of TGF-β1. Suppression of vimentin by siRNA treatment in H2228/CR cells restored the sensitivity to crizotinib. Furthermore, these resistant cells remained highly sensitive to the Hsp90 inhibitors similar to parental cells, H2228. HSP90 inhibition resulted in downregulation of TGF-β receptor II in addition to ALK.

      Conclusion
      EMT should be considered as one of possible acquired resistant mechanisms to crizotinib and HSP90 inhibitors can be a promising therapeutic option for EMT-mediated resistance.