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Effect of Simvastatin on Gefitinib resistance in Non-small Cell Lung Cancer with the T790M Mutation

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Author(s)
황기은
Issued Date
2013
Abstract
비소세포폐암에서 epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)의 초기 임상적 성적들은 실망스런 결과들을 보였으나 비흡연자, 여자, 선암, 아시아의 선택적 환자들에게서 좋은 임상적 결과들을 보여주고 있다. 하지만 EGFR-TKIs에 반응이 있었던 환자에서 수개월에서 수년 후 획득내성이 발생하여 이를 극복하고자 하는 치료제의 개발이 시급한 상황이다.
Statin은 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase의 억제를 통해 항콜레스테롤 효과를 보이는 약제로 이미 항암효과를 보임이 증명되었다. 이 연구는 EGFR의 T790M 획득내성을 가진 비소세포폐암주에서 simvastatin이 mechanism-based approach를 통해 EGFR-TKIs의 내성을 극복할 수 있는지 알아보고자 하였다.
T790M 획득내성을 가진 비소세포폐암주에서 gefitinib과 simvastatin 병합요법시 caspase 의존적인 세포고사가 유도됨을 확인하였다. 또한 병합요법시 AKT/β-catenin activity와 target protein인 cyclin D1과 survivin 역시 감소됨을 확인하였으며, insulin과 AKT overexpression 시에는 p-β-catenin, survivin 발현이 증가됨을 확인하였다. 그러나 AKT에 대한 siRNA나 LY294002을 통한 AKT 억제시 p-β-catenin, survivin 발현이 감소되어 AKT pathway가 target gene인 survivin의 발현을 직접적으로 조절하고 있음을 알 수 있다. Gefitinb과 simvastain의 병합요법에 의해 유도된 세포고사에 survivin의 직접적인 영향을 확인하기위해 survivin siRNA를 처리한 경우 세포고사가 의미있게 증가하였으며 반대로 survivin up-regulation시 세포고사가 감소함을 확인하였다.
결론적으로 simvastatin이 T790M 획득내성을 가진 비소세포페암에서 AKT/β-catenin 신호전달계에 의존적인 survivin의 down-regulation을 통해 EGFR-TKIs에 의한 내성을 극복할 수 있음을 확인하였다.|Although non-small cell lung cancer (NSCLC) tumors with activating mutations in the epidermal growth factor receptor (EGFR) are highly responsive to EGFR tyrosine kinase inhibitors (TKIs) including gefitinib and erlotinib, development of acquired resistance is almost inevitable. Statins show antitumor activity, but it is unknown whether they can reverse EGFR-TKIs resistance in NSCLC with the T790M mutation of EGFR. This study investigated overcoming resistance to EGFR-TKI using simvastatin. We demonstrated that addition of simvastatin to gefitinib enhanced caspase-dependent apoptosis in T790M mutant NSCLC cells. Simvastatin also strongly inhibited AKT activation, leading to suppression of β-catenin activity and the expression of its targets, survivin and cyclin D1. Both insulin treatment and AKT overexpression markedly increased p-β-catenin and survivin levels, even in the presence of gefitinib and simvastatin. However, inhibition of AKT by siRNA or LY294002 treatment decreased p-β-catenin and survivin levels. To determine the role of survivin in simvastatin-induced apoptosis of gefitinib-resistant NSCLC, we showed that the proportion of apoptotic cells following treatment with survivin siRNA and the gefitinib–simvastatin combination was greater than the theoretical additive effects, whereas survivin up-regulation could confer protection against gefitinib and simvastatin-induced apoptosis. Similar results were obtained in erlotinib and simvastatin-treated HCC827/ER cells. These findings suggest that survivin is a key molecule that renders T790M mutant NSCLC cells resistant to apoptosis induced by EGFR-TKIs and simvastatin. Overall, these data indicate that simvastatin may overcome EGFR-TKI resistance in T790M mutant NSCLCs via an AKT/β-catenin signaling-dependent down-regulation of survivin and apoptosis induction.
Alternative Title
T790M 변이를 가진 비소세포폐암에서 gefitinib 내성극복에 대한 simvastatin의 영향
Alternative Author(s)
Hwang, Ki Eun
Affiliation
원광대학교병원 내과
Department
일반대학원 의학과
Advisor
이승일
Awarded Date
2014-02
Table Of Contents
국문초록
ABSTRACT
Ⅰ. Introduction
Ⅱ. Materials and Methods
A. Materials
B. Cell Culture and Viability Test
C. Annexin V Assay for the Assessment of Apoptosis
D. Western Blotting
E. Gene Silencing
F. Establishment of Cells Stably Overexpressing AKT or Survivin
G. Statistical Analysis
Ⅲ. Results
A. Effect of Gefitinib on EGFR Signaling Pathways in EGFR Mutation-positive NSCLC Cell Lines
B. The Combination of Gefitinib and Simvastatin Enhances Caspase-dependent Apoptosis in NSCLC Cells with the T790M Mutation
C. Combination of Gefitinib and Simvastatin Inhibited the Expression of AKT/β-catenin and its Target Genes in NSCLC Cells with the T790M Mutation
D. Down-regulation of Survivin Enhanced Apoptosis Induced by Gefitinib and Simvastatin
E. Up-regulation of Survivin Attenuated Apoptosis Induced by Gefitinib and Simvastatin
F. Combination of Erlotinib and Simvastatin Augmented their Apoptotic Potential via AKT/β-catenin Signaling-dependent Down-regulation of Survivin in NSCLC Cells with the T790M Mutation
Ⅳ. Discussion
Ⅴ. Acknowledgments
References
Degree
Doctor
Publisher
조선대학교 대학원
Citation
황기은. (2013). Effect of Simvastatin on Gefitinib resistance in Non-small Cell Lung Cancer with the T790M Mutation.
Type
Dissertation
URI
https://oak.chosun.ac.kr/handle/2020.oak/11850
http://chosun.dcollection.net/common/orgView/200000264142
Appears in Collections:
General Graduate School > 4. Theses(Ph.D)
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