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  • 學位論文

新穎HDAC抑制劑治療具Gefitinib抗藥性之非小細胞肺癌之研究

A Novel HDAC Inhibitor Treats Non-smal-cell Lung Cancer with Gefitinib Resistance

指導教授 : 陳青周

摘要


亞洲區的非小細胞肺癌(NSCLC)病患,通常表現過度活化之epidermal growth factor receptor (EGFR)。小分子藥物EGFR-tyrosine kinase inhibitors (EGFR-TKIs) 如 gefitinib 和erlotinib ,能有效地抑制過度活化之EGFR,因而抑制癌細胞增生及轉移,然而治療數月後對TKI會產生抗藥性而導致腫瘤之復發,稱為acquired resistance (secondary resistance),其機轉包含 EGFR產生 secondary T790M mutation 和c-Met gene的amplification,進一步探討acquired resistance之機轉可有不同治療策略來克服gefitinib之抗藥性。 本實驗中,對gefitinib產生抗藥性之NSCLC細胞株 (HCC827IR),外觀俱mesenchymal form 伴隨著E-cadherin downregulation和vimentin upregulation,並具癌幹細胞(Cancer stem cells)性質。新穎HDAC 抑制劑 JMF 3086 可以增加E-cadherin以及減少vimentin 的表現,此為抑制Src 活性減少E-cadherin受phosphorylaion,並使Hakai 無法被recruit 到 E-cadherin complex,以減少E-cadherin之endocytosis;JMF 3086也會降低Hakai的生合成而抑制E-cadherin 之endocytosis。 JMF 3086恢復E-cadherin 的表現會減緩NSCLC細胞之生長及轉移和侵入。在動物模式中,JMF3086亦可以減緩NSCLC腫瘤的形成和轉移,並增加E-cadherin 的表現但減少vimentin 和Hakai的表現。因此,JMF 3086 具潛力應用於治療有secondary resistance 之NSCLC 病患。

並列摘要


Somatic activating mutation of epidermal growth factor receptor (EGFR) is found in NSCLC and occurs more frequent in East Asia countries. EGFR-tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib and erlotinib have exhibited superior outcomes against EGFR-mutant NSCLC. However, the patients develop acquired resistance to TKI treatment through T790M secondary mutation and c-Met gene amplification. To further explore the mechanism of acquired resistance provides the differential strategies to overcome gefitinib resistance. In our study, the acquired resistance of EGFR-mutant lung cancer cells HCC827/IR had mesenchymal phenotype accompanied with downregulation of E-cadherin and upregulation of vimentin expression and showed stem cell–like properties. A novel HDAC inhibitor, JMF 3086 could induce E-cadherin and decrease vimentin expression. It was associated with Src inhibition to reduce E-cadherin phosphorylation, leading to decrease in Hakai interacting with E-cadherin complex and reduce E-cadherin endocytosis. JMF3086 also inhibited the expression of Hakai to reduce E-cadherin endocytosis. Restoration of E-cadherin expression by JMF3086 could attenuate cell proliferation and migration in vitro, and retard the tumor growth and metastasis in orthotopic animal model. JMF 3086 also upregulated E-cadherin and downregulated vimentin and Hakai expression in orthotopic lungs. Thus, JMF 3086 was a potential lead compound to treat NSCLC with gefitinib resistance.

參考文獻


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