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Updated: Aug 5, 2026
Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics
Published on: October 2, 2014
Targeting the HSP90/miR-656 axis to suppress lung cancer stem cells and overcome autophagy-mediated drug resistance
Tung-Yu Tiong1, Chun-Hua Wang2, Vijesh Kumar Yadav3
1Division of Thoracic Surgery, Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan; Division of Thoracic Surgery, Department of Surgery, Taipei Medical University-Shuang Ho Hospital, New Taipei City, 235, Taiwan.
Background:
Lung cancer remains a leading cause of cancer-related mortality worldwide, with treatment outcomes severely limited by drug resistance and tumor recurrence. Lung cancer stem cells (LCSCs) are increasingly recognized as key drivers of therapeutic failure, underscoring the need for strategies that target stemness-associated survival mechanisms such as autophagy.
Methods:
Human non-small cell lung cancer (NSCLC) cell lines, including gefitinib-resistant models, were used to enrich LCSCs populations through tumorsphere culture. Stemness, autophagy, and drug-resistance signaling were assessed using tumorsphere formation assays, Western blotting, immunofluorescence, and quantitative RT-PCR. MicroRNA profiling and in silico analyses were performed to identify regulatory miRNAs targeting HSP90. Therapeutic efficacy was evaluated in vivo using NSCLC xenograft models treated with gefitinib and/or the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG).
Results:
HSP90 inhibition markedly reduced tumorsphere formation, self-renewal capacity, and stemness-associated signaling in LCSCs. 17-AAG suppressed gefitinib-induced autophagy through downregulation of Beclin-1 and LC3, accompanied by reduced expression of the stemness-promoting oncogene c-Met. MicroRNA analysis identified hsa-miR-656 as a tumor-suppressive regulator inversely correlated with HSP90 expression. In vivo, combined HSP90 and EGFR inhibition significantly reduced tumor burden, suppressed autophagy and drug resistance, alongside increased systemic levels of hsa-miR-656.
Conclusion:
These findings identify the HSP90/c-Met/Beclin-1 axis as a critical regulator of autophagy-dependent LCSC survival and drug resistance in NSCLC. Targeting this pathway using HSP90 inhibition, alone or in combination with EGFR-TKIs, represents a promising strategy to overcome therapeutic resistance and prevent tumor recurrence.
Insights
Targeting heat shock protein 90 (HSP90) inhibits lung cancer stem cell survival and drug resistance by blocking autophagy. This approach, combined with EGFR inhibitors, offers a promising strategy to overcome treatment failure and prevent recurrence in non-small cell lung cancer.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Stem Cell Research
Background:
- Lung cancer is a leading cause of cancer mortality, with treatment limited by drug resistance and recurrence.
- Lung cancer stem cells (LCSCs) drive therapeutic failure by promoting stemness and survival.
- Targeting LCSC survival mechanisms like autophagy is crucial for improving treatment outcomes.
Purpose of the Study:
- To investigate the role of heat shock protein 90 (HSP90) in regulating lung cancer stem cell (LCSC) survival, autophagy, and drug resistance.
- To evaluate the therapeutic potential of HSP90 inhibition, alone or in combination with EGFR inhibitors, in non-small cell lung cancer (NSCLC).
Main Methods:
- Enrichment of LCSCs using tumorsphere culture from NSCLC cell lines, including gefitinib-resistant models.
- Assessment of stemness, autophagy, and drug resistance signaling via tumorsphere assays, Western blotting, immunofluorescence, and qRT-PCR.
- MicroRNA profiling and in silico analysis to identify miRNAs targeting HSP90; in vivo efficacy evaluation in NSCLC xenograft models.
Main Results:
- HSP90 inhibition significantly reduced LCSC self-renewal, stemness, and tumorsphere formation.
- The HSP90 inhibitor 17-AAG suppressed gefitinib-induced autophagy by downregulating Beclin-1 and LC3, and reduced c-Met expression.
- Combined HSP90 and EGFR inhibition in vivo reduced tumor burden, suppressed autophagy and drug resistance, and increased hsa-miR-656 levels.
Conclusions:
- The HSP90/c-Met/Beclin-1 axis is a critical regulator of autophagy-dependent LCSC survival and drug resistance in NSCLC.
- Targeting HSP90, alone or with EGFR-TKIs, is a promising strategy to overcome therapeutic resistance and prevent lung cancer recurrence.
