Role of survivin in EGFR inhibitor-induced apoptosis in non-small cell lung cancers positive for EGFR mutations

The molecular mechanism by which epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) induce apoptosis in non-small cell-lung cancer (NSCLC) cells that are positive for activating mutations of the EGFR remains unclear. In this study, we report the effects of the EGFR-TKI gefitinib on expression of the antiapoptotic protein survivin that have functional consequences in EGFR mutation-positive NSCLC cells. Immunoblot analysis revealed that gefitinib downregulated survivin expression, likely through inhibition of the PI3K-AKT signaling pathway, in NSCLC cells positive for EGFR mutation. Stable overexpression of survivin attenuated gefitinib-induced apoptosis and also inhibited the antitumor effect of gefitinib in human tumor xenografts. Furthermore, the combination of survivin overexpression with inhibition of the gefitinib-induced upregulation of the proapoptotic protein BIM attenuated gefitinib-induced apoptosis to a greater extent than either approach alone. Our results indicate that downregulation of survivin plays a pivotal role in gefitinib-induced apoptosis in EGFR mutation-positive NSCLC cells. Furthermore, they suggest that simultaneous interruption of the PI3K-AKT-survivin and MEK-ERK-BIM signaling pathways is responsible for EGFR-TKI-induced apoptotic death in these cells.     

EGFR基因突变NSCLC脑转移瘤放疗联合TKI研究现状

非小细胞肺癌(NSCLC)脑转移的患者预后较差,酪氨酸酶抑制剂(TKI)显著改善了表皮生长因子受体(EGFR)基因敏感突变患者的预后。EGFR敏感突变与NSCLC的脑转移发生率相关并可能影响其放疗和药物治疗疗效,脑转移瘤的EGFR-TKI单药治疗和放疗均有效,二者联合是否较单一治疗改善EGFR基因突变的NSCLC脑转移...     

Afatinib and lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) have an established role in the treatment of non-small-cell lung cancer (NSCLC). First-generation reversible ATP-competitive EGFR-TKIs are approved for the initial treatment of patients with EGFR mutation-positive advanced NSCLC. Afatinib is an irreversible second-generation EGFR-TKI with potent preclinical activity against EGFR (wild type and mutant), HER2, HER4 and EGFR-mutant NSCLC with acquired resistance to reversible EGFR-TKI. LUX-Lung 3 trial demonstrated superiority of afatinib to cisplatin and pemetrexed in the frontline treatment of treatment-naïve patients with advanced adenocarcinoma of the lung and EGFR mutation. Based on these results, afatinib was recently approved for the first-line treatment of NSCLC patients with EGFR mutation. This article summarizes current status of preclinical and clinical development of afatinib in NSCLC.     

非小细胞肺癌EGFR-TKI耐药的分子机制及防治策略

目的 近年来EGFR酪氨酸激酶抑制剂(epidermal growth factor receptor tyrosine kinase inhibitor,EGFR-TKI)是EGFR突变型晚期NSCLC的重要治疗手段之一,然而,绝大部分患者治疗9～13个月后即出现耐药.EGFR-TKIs的耐药机制和耐药后治疗策略已成为基础和临床研究的热点.探讨非小细胞肺癌中表皮生长因子受体酪氨酸激酶抑制剂(epithelial growth factor receptor tyrosine kinase inhibitor,EGFR-TKI)耐药的分子机制及防治策略.方法 应用Pubmed和CNKI期刊全文数据库检索系统,以“EGFR TKI和耐药”为关键词,检索2005-01-2016-05的相关文献.纳入标准:(1) EGFR TKI耐药的定义;(2)EGFR-TKI的耐药分类;(3)EGFR-TKI耐药的分子机制;(4) EGFR-TKI耐药的防治策略.纳入57篇文献进行分析.结果 EGFR TKI耐药分为原发性耐药和获得性耐药.原发性耐药机制包括不同EGFR突变位点的敏感性差异和KRAS突变等,获得性耐药机制包括T790M突变、EGFR下游信号分子活化、旁路激活及表型转化等.耐药后仍缺乏标准治疗策略,可继续EGFR-TKI治疗、EGFR-TKI联合化疗或其他靶向治疗或改为化疗;基于耐药靶点的治疗策略,如第三代EGFR-TKI、Met抑制剂等也可作为选择.结论 EGFR-TKI耐药机制复杂,缺乏标准耐药治疗策略,基于临床治疗模式和耐药靶点的治疗策略有望为EGFR-TKI耐药患者的个体化治疗提供思路.     

免疫检查点抑制剂在EGFR突变非小细胞肺癌治疗应用的研究进展

目前,表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor-tyrosine kinase inhibitor,EGFR-TKI)是表皮生长因子受体(epidermal growth factor receptor,EGFR)基因敏感突变晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)的一线治疗标准,但大多数患者最终出现获得性耐药。而针对免疫检查点程序性死亡受体(programmed death-1,PD-1)及其配体(PD-1 ligand,PD-L1)的抑制剂取得突破性进展,改变了NSCLC的治疗模式。多项研究显示,EGFR敏感突变NSCLC患者免疫检查点抑制剂疗效不佳,其可能机制主要包括EGFR敏感突变患者PD-L1的低表达、抑制性免疫微环境、低肿瘤突变负荷等等。通过对EGFR突变NSCLC患者特殊人群的选择,免疫检查点抑制剂与其他药物的联合应用,可能为EGFR敏感突变NSCLC患者的治疗带来希望。本文将对此进行综述,以期为表皮生长因子受体突变的非小细胞肺癌患者的治疗带来新的希望。     

表皮生长因子受体突变晚期非小细胞肺癌靶向治疗效果影响因素分析

目的:探讨表皮生长因子受体（EGFR）突变晚期非小细胞肺癌（NSCLC）EGFR-酪氨酸激酶抑制剂（EGFR-TKI）治疗效果的影响因素。方法:收集2015年1月至2019年10月南京医科大学附属无锡第二医院接受EGFR-TKI治疗的104例EGFR突变晚期NSCLC患者的临床资料。分析EGFR突变类型与患者的临床病理...     

VEGF抑制剂联合酪氨酸激酶抑制剂一线治疗EGFR突变晚期非小细胞肺癌的疗效和安全性

目的:探讨血管内皮生长因子(vascular endothelial growth factor,VEGF)抑制剂联合酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKI)一线治疗表皮生长因子受体(epidermal growth factor receptor,EGFR)突变晚期非小细胞肺癌...     

Cell Free Tumoral DNA Versus Paraffin Block Epidermal Growth Factor Receptor Mutation Detection in Patients with Non-Small Cell Lung Cancer

Increasing knowledge about the molecular profile of tumors has led to personalized treatment for achieving better outcomes in patients with nonsmall cell lung cancer (NSCLC). Currently, finding exact somatic genomic changes of tumor has gained great importance. On the other hand, crescendoing needs to actual tumor tissue at different time points during cancer treatment may produce major discomfort for NSCLC patients. Tumor genomes can be reconstructed by information obtained from circulating cell-free deoxyribonucleic acid (cfDNA) of peripheral blood. cfDNA may be represented as a suitable alternative test  for epidermal growth factor receptor (EGFR) mutation detection in these patients. This study aimed to assess validity of cfDNA in somatic EGFR mutation identification in Iranian NSCLC cases. Methods: Somatic mutation of EGFR gene was studied in both tissue specimens and plasma. Then, mutations were detected by polymerase chain reaction(PCR) and sequencing. Results: We observed a high concordance (90%) between tissue samples and cfDNA for EGFR gene mutation.  The sensitivity, accuracy, and positive precision value were 90%, 90% and 100%, respectively. A false negative rate of 10% was also demonstrated in this study. Conclusion: We established sensitive methods for detecting EGFR gene mutation which may be very useful in clinical practice.     

Combined Inhibition of the VEGFR and EGFR Signaling Pathways in the Treatment of NSCLC

Multitargeted agents represent the next generation of targeted therapies in solid tumors. The benefits of individually targeting the vascular endothelial growth factor receptor (VEGFR) and epidermal growth factor receptor (EGFR) signaling pathways have been clinically validated in recent years in a number of solid tumor types including non‐small cell lung cancer (NSCLC). Given the heterogeneity of this tumor type and potential crosstalk between these key signaling pathways (which are known to play a critical role in tumor growth, metastasis, and angiogenesis), dual inhibition of the VEGFR and EGFR signaling pathways has the potential to offer additional clinical benefits in NSCLC. A number of approaches to inhibiting both VEGFR and EGFR signaling are currently under investigation, including monotherapy with a multitargeted tyrosine kinase inhibitor (e.g., vandetanib, AEE788, XL647, BMS‐690514) or a combination of single‐targeted therapies (e.g., bevacizumab, cetuximab, erlotinib, gefitinib). Preclinical and early clinical data (phase I and II trials) support combined inhibition of the VEGFR and EGFR pathways in NSCLC. Overall, combined inhibition strategies are well tolerated and have shown promise in early clinical studies. Ongoing phase II and phase III trials will determine the clinical potential of a number of dual inhibition strategies in the treatment of advanced NSCLC.     

An in vitro chemoresponse assay defines a subset of colorectal and lung carcinomas responsive to cetuximab

Cetuximab is a chimeric monoclonal antibody for the epidermal growth factor receptor (EGFR) that may provide benefit to select cancer patients; however, identification of the characteristics of those patients who may benefit from its use is not complete. The ChemoFx? drug response marker (DRM) is an in vitro assay that can provide drug response data on tumor specimens before any patient treatment is initiated. We determined the feasibility of using the ChemoFx DRM to test tumor samples for sensitivity to cetuximab. We exposed four non-small cell lung carcinoma (NSCLC) cell lines (H358, H520, HCC827, and H1666) to cetuximab and determined their sensitivity using the ChemoFx DRM and, in parallel, EGFR status using immunocytochemistry, Western blotting, and In-Cell Western (TM) analysis. We used the ChemoFx DRM to determine cetuximab sensitivity of primary NSCLC and colorectal tumor samples. The ChemoFx DRM distinguished between cetuximab-sensitive and -resistant cell lines. Cetuximab sensitivity was not dependent on EGFR mutational status; H358 cells were non-responsive to cetuximab yet contain wild-type EGFR, whereas H1666 cells were intermediately responsive to cetuximab and contain wild-type EGFR. HCC827 (EGFR-mutant) cells were intermediately responsive and, as expected, H520 cells (EGFR-null) were non-responsive to cetuximab. ChemoFx-determined cetuximab sensitivity of primary NSCLC and colorectal tumor samples was 9.0% and 7.5%, respectively. Use of the ChemoFx DRM is feasible for determining cetuximab sensitivity. The ChemoFx-determined cetuximab responses of primary NSCLC and colorectal tumor specimens were similar to published response rates of patients to treatment with cetuximab monotherapy.     

JAK2 inhibitor TG101348 overcomes erlotinib-resistance in non-small cell lung carcinoma cells with mutated EGF receptor

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are responsive to EGFR-tyrosine kinase inhibitor (EGFR-TKI). However, NSCLC patients with secondary somatic EGFR mutations are resistant to EGFR-TKI treatment. In this study, we investigated the effect of TG101348 (a JAK2 inhibitor) on the tumor growth of erlotinib-resistant NSCLC cells. Cell proliferation, apoptosis, gene expression and tumor growth were evaluated by diphenyltetrazolium bromide (MTT) assay, flow cytometry, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining, Western Blot and a xenograft mouse model, respectively. Results showed that erlotinib had a stronger impact on the induction of apoptosis in erlotinib-sensitive PC-9 cells but had a weaker effect on erlotinib-resistant H1975 and H1650 cells than TG101348. TG101348 significantly enhanced the cytotoxicity of erlotinib to erlotinib-resistant NSCLC cells, stimulated erlotinib-induced apoptosis and downregulated the expressions of EGFR, p-EGFR, p-STAT3, Bcl-xL and survivin in erlotinib-resistant NSCLC cells. Moreover, the combined treatment of TG101348 and erlotinib induced apoptosis, inhibited the activation of p-EGFR and p-STAT3, and inhibited tumor growth of erlotinib-resistant NSCLC cells in vivo. Our results indicate that TG101348 is a potential adjuvant for NSCLC patients during erlotinib treatment.     

Response to dual blockade of epidermal growth factor receptor (EGFR) and cycloxygenase-2 in nonsmall cell lung cancer may be dependent on the EGFR mutational status of the tumor

BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated clinical benefit in patients with nonsmall cell lung cancer (NSCLC), particularly those with tumors that have EGFR-TK domain mutations. Moreover, the EGFR and cyclooxygenase (COX)-2 pathways are known to enhance the procarcinogenic effects of each other in different tumor types. Therefore, it was hypothesized that tumor EGFR mutation status may influence the effectiveness of simultaneous EGFR and COX-2 inhibition in patients with NSCLC. METHODS: Three NSCLC cell lines with varying EGFR mutation status and sensitivities to EGFR-TKIs were selected: H3255 (L858R), H1650 (del E746-A750), and H1781 (wild-type EGFR). Cells were treated with erlotinib, gefitinib, or celecoxib alone, and the combination of both EGFR-TKI inhibitors with celecoxib. Cell survival and apoptosis was assessed and correlated with the expression of COX-2, EGFR, pEGFR, Akt, pAkt, expression, and derived prostaglandin E2 (PGE(2)). RESULTS: Celecoxib by itself was found to have no effects on cell growth or apoptosis in any of the cell lines. Erlotinib and gefitinib inhibited cell growth and induced apoptosis in both mutant cell lines and did so in H1781 cells at 10-fold higher concentrations. Celecoxib when added to erlotinib or gefitinib significantly enhanced the antiproliferative and proapoptotic effects in both mutant cell lines but had no additional effects in H1781 cells. Greater down-regulation of COX-2, EGFR, pEGFR, Akt, pAkt, and PGE(2) was found when H3255 cells were treated with the combination compared with any of the single agents alone. CONCLUSIONS: The results of the current study demonstrate that the effectiveness of the addition of celecoxib to an EGFR-TKI is significantly greater in NSCLC cells with EGFR mutations, which is likely due to more complete inhibition of both pathways.     

miRNAs与非小细胞肺癌EGFR突变及放疗相关性研究进展

EGFR作为NSCLC靶向治疗的热点,近年来其在分子生物学水平的研究众多。而放疗作为一种NSCLC重要的传统治疗方法,其疗效与EGFR突变及过表达相关。放疗联合EGFR-TKI在NSCLC治疗上的疗效还缺乏Ⅲ期临床结果。miRNAs能够调控肿瘤相关基因表达,影响肿瘤生物学活动。近来研究显示miRNAs对EGFR突变、EGFR-TKI和放疗均存在正向或负向的调控作用,其具体机制已部分阐明。现就miRNAs对EGFR突变、EGFR-TKI及放疗间相关性作一综述,旨在为miRNAs应用于放疗联合EGFR-TKI治疗NSCLC提供最新诊疗依据。     

Clinicopathologic Features and Immune Microenvironment of Non–Small-cell Lung Cancer With Primary Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Background

Approximately 20% to 30% of non–small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-activating mutations are not responsive to EGFR tyrosine kinase inhibitors (TKIs). Although primary resistance to EGFR-TKIs has been attributed to various genetic alterations, little is known about the clinical and immunopathologic features of patients with primary resistance. The tumor immune microenvironment, including tumor-infiltrating lymphocytes (TILs) and programmed cell death ligand 1 (PD-L1), has been reported to play an important role in tumor progression in those with NSCLC. However, few studies have directly focused on the relationship between the tumor immune microenvironment and primary resistance to EGFR-TKIs.

Epidermal growth factor receptors harboring kinase domain mutations associate with the heat shock protein 90 chaperone and are destabilized following exposure to geldanamycins

Somatic mutations in the kinase domain of the epidermal growth factor receptor (EGFR), including L858R and exon 19 deletions, underlie responsiveness to gefitinib and erlotinib in non-small cell lung cancer (NSCLC). Acquired resistance to these tyrosine kinase inhibitors is in some cases mediated by a second mutation, T790M. Ansamycin antibiotics, such as geldanamycin, potently inhibit heat shock protein 90 (Hsp90), promoting ubiquitin-mediated degradation of oncogenic kinases that require the chaperone for proper conformational folding. Here, we show that L858R and deletion mutant EGFR proteins found in NSCLC interact with the chaperone and are sensitive to degradation following Hsp90 inhibition. In NIH/3T3 cells expressing either wild-type or mutant EGFR, diminution of expression of both L858R and EGFR delL747-S752, P753S occurred following exposure to 50 nmol/L geldanamycin over 24 hours, whereas partial diminution of wild-type EGFR required a minimum of 200 nmol/L drug. In time course experiments, mutant EGFR expression was depleted after only 4 hours of exposure to 1 micromol/L geldanamycin, whereas diminution of wild-type EGFR was less substantial and seen only following 12 hours. Similarly, EGFR proteins in NSCLC cell lines harboring EGFR mutations, including NCI-H1650, NCI-H3255, and NCI-H1975, were also more sensitive to geldanamycin-induced degradation compared with the protein in wild-type cells. Exposure of EGFR-mutant cell lines to geldanamycin induced marked depletion of phospho-Akt and cyclin D1 as well as apoptosis. These data suggest mutational activation of EGFR is associated with dependence on Hsp90 for stability and that Hsp90 inhibition may represent a novel strategy for the treatment of EGFR-mutant NSCLC.     

Immune Marker Profiling and Programmed Death Ligand 1 Expression Across NSCLC Mutations

Introduction

Programmed death 1/programmed death ligand 1 (PD-L1) axis inhibitors have been proven effective, especially in patients with tumors expressing PD-L1. Their clinical efficacy in patients with EGFR-activating mutations is still unclear, whereas KRAS mutations seem to be associated with good response.

Discovery of a Potent and Mutant-Selective EGFR Inhibitor that Overcomes T790M-Mediated Resistance in Lung Cancer

Background

Despite remarkable activity in epidermal growth factor receptor (EGFR)-mutant lung cancer patients, the clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) is limited by the emergence of acquired resistance, which is mostly caused by a secondary T790M mutation. Fortunately, newly developed, mutant-selective EGFR-TKIs against T790M have been proven as an effective therapeutic approach although only osimertinib has received the FDA approval until now.

Objective

To determine the in vitro and in vivo efficacy of a new EGFR TKI, OBX1-012 in cells with mutant EGFR.

Methods

Effects of OBX1-012 on cellular viability and EGFR-related signaling were determined in EGFR-mutant non-small cell lung cancer (NSCLC) cells, including cells harboring T790M mutations. In addition, in vivo efficacy of OBX1-012 was evaluated in xenograft models.

Results

We report the discovery and preclinical assessment of another novel, mutant-selective EGFR-TKI, OBX1-012. Compared with other mutant-selective EGFR-TKIs such as olumitinib and osimertinib, it showed similar potency and selectivity for mutant EGFR. OBX1-012 treatment was highly effective against human EGFR-mutant lung cancer models with or without EGFR T790M, not only in vitro but also in vivo. However, OBX1-012 like other EGFR-TKIs failed to exhibit efficacy for the exon 20 insertion mutation or C797S mutation, which was generated by site-directed mutagenesis and stable transfection of Ba/F3 cells.

Conclusions

These results identify OBX1-012 as a highly effective, mutant-selective EGFR-TKI for the treatment of T790M-mediated resistance in NSCLC.

     

自噬在EGFR-TKI类肿瘤靶向药物对肺癌的治疗和耐药中作用的研究进展

表皮生长因子受体激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitor, EGFR-TKI）是一类针对肿瘤细胞中EGFR的异常活化而开发的肿瘤靶向药物,可以有效抑制带有EGFR敏感突变的肿瘤细胞的生长。然而先天性以及获得性耐药严重制约了该类药物的使用。近些年的研究发现自噬（autophagy）,作为一个细胞编码的高度保守的应对压力的存活机制,其与肿瘤的发生发展及抗肿瘤药物的耐药密切相关。EGFR的激活可以通过多条通路调控自噬。EGFR-TKI也可以诱导自噬,且自噬在EGFR-TKI的治疗和产生耐药性的过程中发挥着双刃剑的作用：一方面EGFR-TKI诱导的自噬是肿瘤细胞的一个保护机制,联合使用自噬抑制剂可以增强药物的细胞毒性效果;同时还有研究证明EGFR-TKI诱导的高水平自噬可以在凋亡缺陷的细胞中造成自噬性死亡,这种情况下联合使用自噬诱导剂则可能产生更好的效果。因此,针对不同的情况通过调控自噬以提高EGFR-TKI的治疗效果是一个颇具前景的治疗方案。本文对EGFR-TKI和自噬相关的信号通路进行了阐述,并对自噬在EGFR-TKI类药物对肺癌的治疗和耐药中作用的最新研究进展进行了总结,为设计联合方案提高EGFR-TKI的抑制效果,降低耐药性提供线索。