Curcumin overcome primary gefitinib resistance in non-small-cell lung cancer cells through inducing autophagy-related cell death

Ping Chen,Xiao-Hui Zhao,Jian Li,Han-Peng Huang,Wei-Guo Long,Jun Jin,Chen-Guo Chen,Kan Chen,Yi Wang

doi:10.1186/s13046-019-1234-8

Ping Chen, Xiao-Hui Zhao + Show 7 more

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https://doi.org/10.1186/s13046-019-1234-8

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Abstract

BackgroundEpidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are being wildly used as target therapy in non-small-cell lung cancer (NSCLC). However, NSCLC patients with wild-type EGFR and KRAS mutation are primary resistant to EGFR-TKIs such as gefitinib. Curcumin has been known as a potential therapeutic agent for several major human cancers. In this study, we investigated the effect of curcumin on the reversal of gefitinib resistance in NSCLC cells as well as their molecular bases.MethodsH157 (wild-type EGFR and KARS mutation) and H1299 (wild-type EGFR and HRAS mutation) cells were treated with gefitinib or curcumin alone, or the two combination, and then cell viability, EGFR activity, expressions of Sp1 and Sp1-dependent proteins and receptor tyrosine kinases, markers of autophagy and apoptosis were examined by using CCK-8, colony formation, immunoblot, quantitative PCR, immunofluoscence, and flow cytometry assays. Also xenograft experiments were conduced to test the synergism of curcumin to gefitinib.ResultsOur results showed that curcumin significantly enhanced inhibitory effect of gefitinib on primary gefitinib-resistant NSCLC cell lines H157 and H1299. Combination treatment with curcumin and gefitinib markedly downregulated EGFR activity through suppressing Sp1 and blocking interaction of Sp1 and HADC1, and markedly suppressed receptor tyrosine kinases as well as ERK/MEK and AKT/S6K pathways in the resistant NSCLC cells. Meanwhile, combination treatment of curcumin and gefitinib caused dramatic autophagy induction, autophagic cell death and autophagy-mediated apoptosis, compared to curcumin or gefitinib treatment alone, as evidenced by the findings that curcumin and gefitinib combination treatment-produced synergistic growth inhibition and apoptosis activation can be reversed by pharmacological autophagy inhibitors (Baf A1 or 3-MA) or knockdown of Beclin-1 or ATG7, also can be partially returned by pan-caspase inhibitor (Z-VAD-FMK) in H157 and H1299 cells. Xenograft experiments in vivo yielded similar results.ConclusionsThese data indicate that the synergism of curcumin on gefitinib was autophagy dependent. Curcumin can be used as a sensitizer to enhance the efficacy of EGFR-TKIs and overcome the EGFR-TKI resistance in NSCLC patients with wild-type EGFR and/or KRAS mutation.

Highlights

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are being wildly used as target therapy in non-small-cell lung cancer (NSCLC)
Curcumin enhances the inhibitory effect of gefitinib on gefitinib-resistant NSCLC cells by suppressing EGFR activity Since NSCLCs with wild-type EGFR and KRAS mutation were shown to be primary resistant to EGFR-TKIs [9, 10], we examined the inhibitory effect of gefitinib on proliferation of NSCLC cells with different gene background
We found that synergism of curcumin to gefitinib is more pronounced in gefitinib-resistant cells than in gefitinibsensitive cells, and gefitinib induced lesser extent downregulation of EGFR activity in gefitinib-resistant cells compared to gefitinib-sensitive cells, suggesting that the insensitivity to gefitinib- induced downregulation of EGFR activity may be involved in gefitinib primary resistance in NSCLC cells, and curcumin reverse gefitinib resistance at least partially through suppressing EGFR activity

Summary

Introduction

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are being wildly used as target therapy in non-small-cell lung cancer (NSCLC). NSCLC patients with wild-type EGFR and KRAS mutation are primary resistant to EGFR-TKIs such as gefitinib. We investigated the effect of curcumin on the reversal of gefitinib resistance in NSCLC cells as well as their molecular bases. Epidermal growth factor receptor (EGFR), an oncogenic receptor tyrosine kinase, plays a key role in the development and progression of non-small-cell lung cancer (NSCLC) [1]. NSCLC overexpressing wild- type EGFR are often primary resistant, especially in tumor with concurrent KRAS mutation [9, 10]. The reasons for the innate resistance to EGFR-TKIs in wild-type EGFR and KRAS mutation NSCLC tumors still remain ill-defined. Developments of new EGFR-TKI sensitizers and combination strategies to surmount primary resistance to EGFR-TKIs are urgently required in patients with wildtype EGFR and KRAS mutation

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Conclusion