Activation of the HSP27-AKT axis contributes to gefitinib resistance in non-small cell lung cancer cells independent of EGFR mutations

Seul Ki Choi, Minsuh Kim, Haeseung Lee, Youngjoo Kwon, Hyuk Jin Cha, Se Jin Jang, Younghwa Na, Yun Sil Lee

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Purpose: Although epidermal growth factor receptor (EGFR)-activating mutations in non-small cell lung cancer (NSCLC) usually show sensitivity to first-generation EGFR-tyrosine kinase inhibitors (TKIs), most patients relapse because of drug resistance. Heat shock protein 27 (HSP27) has been reported to be involved in the resistance of EGFR-TKIs, although the underlying mechanism is unclear. Here, we explore the mechanisms of HSP27-mediated EGFR TKI resistance and propose novel therapeutic strategies. Methods: To determine the mechanism of HSP27 associated gefitinib resistance, differences were assessed using gefitinib-sensitive and -resistant NSCLC cell lines. In vivo xenograft experiments were conducted to elucidate the combinatorial effects of J2, a small molecule HSP27 inhibitor, and gefitinib. Analyses of human NSCLC tissues and PDX tissues were also used for comparison of HSP27 and phosphorylated AKT expression. Results: Large-scale cohort analysis of NSCLC cases revealed that HSP27 expression correlated well with the incidence of EGFR mutations and affected patient survival. Increased pAKT and HSP27 was observed in gefitinib-resistant cells compared with gefitinib-sensitive cells. Moreover, increased phosphorylation of HSP27 by gefitinib augmented its protein stability and potentiated its binding activity with pAKT, which resulted in increased gefitinib resistance. However, in gefitinib-sensitive cells, stronger binding activity between EGFR and HSP27 was observed. Moreover, these phenomena occurred regardless of EGFR mutation including secondary mutations, such as T790M. AKT knockdown switched HSP27-pAKT binding to HSP27-EGFR, which promoted gefitinib sensitivity in gefitinib-resistant cells. Functional inhibition of HSP27 yielded sensitization to gefitinib in gefitinib-resistant cells by inhibiting the interaction between HSP27 and pAKT. Conclusions: Our results indicate that combination of EGFR-TKIs with HSP27 inhibitors may represent a good strategy to overcome resistance to EGFR-TKIs, especially in cancers exhibiting AKT pathway activation.

Original languageEnglish
Pages (from-to)913-930
Number of pages18
JournalCellular Oncology
Issue number5
StatePublished - Oct 2022

Bibliographical note

Funding Information:
This work was supported by grants from the National Research Foundation of Korea, (2020M2D9A2093974, 2020R1A2C3013255, and 2018R1A5A2025286) funded by the Korean government (Ministry of Science and ICT).

Publisher Copyright:
© 2022, The Author(s).


  • AKT activation
  • EGFR-TKI resistance
  • Heat shock protein 27 (HSP27)
  • Non-small cell lung cancer (NSCLC)


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