吉非替尼在非小细胞肺癌治疗中耐药机制的研究进展

吉非替尼(gefitinib)是表皮生长因子受体(epidermal growth factor receptor,EGFR)酪氨酸激酶抑制剂类靶向药物,与传统化疗药物相比,从细胞受体、增值调控的分子水平对肿瘤发病机制进行调控的靶向药物吉非替尼可使EGFR突变阳性患者的无疾病进展生存期显著延长。     

EGFR TKIs在非小细胞肺癌中的耐药机制及治疗进展

吉非替尼和厄洛替尼是表皮生长因子受体(epidermal growth factor receptor,EGFR)酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKIs),广泛用于非小细胞肺癌的治疗。但随着应用的深入,耐药问题开始凸显。过去几年,针对继发性耐药和原发性耐药的深入研究,发现EGFR二次突变,MET基因扩增, K-ras基因突变等是EGFR TKIs耐药的主要原因。本文就EGFR-TKIs原发耐药与继发耐药的机制,以及克服此类耐药的新型药物及其临床试验数据作一综述。     

表皮生长因子受体酪氨酸激酶突变对于非小细胞肺癌疗效影响的研究进展

随着肺癌发病机制研究的深入,靶向治疗在NSCLC治疗中的地位日渐重要.其中,以厄洛替尼和吉非替尼为代表的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)的靶向药物取得了一定的疗效.     

KRAS突变在非小细胞肺癌中的研究进展

一些非小细胞肺癌(non-small cell lung cancer,NSCLC)存在某个特定突变基因,它被认为是导致癌症的主要启动基因.肺癌中两个最常见的突变基因分别编码表皮生长因子受体(epidermal growth factor receptor,EGFR)和KRAS.EGFR酪氨酸激酶结构域突变最近才确定,但它已被临床确立为评估表皮生长因子受体酪氨酸激酶抑制剂(吉非替尼和厄洛替尼)治疗敏感性的有效预测指标.     

非小细胞肺癌中EGFR酪氨酸激酶抑制剂获得性耐药的机制

表皮生长因子受体(epidermal growth factor receptor,EGFR)酪氨酸激酶抑制剂--厄洛替尼,可有效治疗含有EGFR突变的非小细胞肺癌(non-small cell lung cancer,NSCLC),然而,分子靶向药物疗效维持时间较短,几乎所有起初治疗有效的患者最终均会复发,提示对此类药物产生耐药.     

影响表皮生长因子受体靶向治疗的相关分子检测

近年来,肿瘤分子靶向治疗药物不断出现,其中表皮生长因子受体(epidermal growth factor receptor,EGFR)成为治疗的重要靶点.针对EGFR治疗的策略有两类,一类是作用于胞外配体结合区的单克隆抗体,如西妥昔单抗、帕尼单抗和尼妥珠单抗;另一类是胞内酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKI),如吉非替尼、埃罗替尼等.     

表皮生长因子受体和血管内皮细胞生长因子受体之外肺癌靶向治疗新进展

目前肺癌的生物靶向治疗已进入临床治疗阶段,以吉非替尼、厄洛替尼和西妥昔单抗为代表的抗表皮生长因子受体(epidermal growth factor receptor, EGFR)通路的药物和以贝伐单抗为代表的抗血管内皮细胞生长因子受体(vascular endothelial cell growth factor receptor, VEGFR)通路的药物已成功地应用于肺癌临床治疗.然而,肺癌分子生物学机制十分复杂,以EGFR和VEGFR信号通路为靶点的治疗存在局限和不足.近年来,肺癌新的分子生物靶点逐渐受到关注,例如棘皮动物微管相关蛋白4/间变淋巴瘤激酶(echinoderm microtubule-associated protein-like 4/anaplastic lymphoma kinase, EML4-ALK)融合基因、哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin, mTOR)、胰岛素样生长因子Ⅰ型受体(insulin-like growth factor type Ⅰ receptor, IGF-1R)和间质上皮转变因子(mesenchymal-epithelial transition factor, c-MET)等.本文对上述分子生物学标志物在肺癌治疗中的作用及其相关临床研究进展进行综述.     

阿法替尼成功治疗伴有EGFR罕见复合突变的肺腺癌脑膜转移1例报告及文献复习

既往关于表皮生长因子受体(epidermal growth factor receptor,EGFR)复合突变肺腺癌脑膜转移患者采用脑脊液基因检测明确EGFR突变情况并指导治疗的研究较少.2019年3月31日,天津市环湖医院肿瘤介入科收治1例42岁女性肺腺癌柔脑膜转移患者,对吉非替尼、奥西替尼、放化疗无效.患者情况危急...     

IGF-1R抑制剂联用可增强人非小细胞肺癌PC9/G细胞对吉非替尼的敏感性

目的:观察单用表皮生长因子受体(epidermal growth factor receptor, EGFR)的酪氨酸激酶抑制剂吉非替尼 (ge? tinib) 或联合胰岛素生长因子-1受体(insulin-like growth factor-1 receptor,IGF-1R)的酪氨酸激酶抑制剂AG1024作用于人非小细胞肺癌耐药株PC9/G细胞后,该细胞对吉非替尼耐药性的影响,并探讨IGF-1R与肿瘤细胞耐药的相关机制。方法:用吉非替尼和AG1024单独或联合作用于PC9/G细胞后,采用MTT法分别检测各组细胞的增殖情况,并利用中效原理判断两药联用的效果;FCM法检测各组细胞的凋亡情况;Western印迹法检测各组细胞的磷酸化EGFR(phosphorylated EGFR, p-EGFR)、磷酸化Akt(phosphorylated Akt,p-Akt)和磷酸化细胞外信号调节激酶(phosphorylated extracellular signal-regulated kinase,p-ERK)的表达水平。结果:吉非替尼和AG1024单独作用于PC9/G细胞后,均出现不同程度的细胞增殖抑制作用和细胞凋亡促进作用;而吉非替尼和AG1024联合作用,能更显著地抑制细胞增殖,且凋亡细胞显著增加(P<0.05)。 Western印迹法检测发现,联合用药组的p-EGFR、p-Akt和p-ERK蛋白表达量明显减少。结论:IGF-1R抑制剂AG1024和EGFR抑制剂吉非替尼联用具有较好的协同作用,可能通过抑制细胞增殖和促进细胞凋亡,提高耐药细胞对吉非替尼的敏感性。     

阿帕替尼逆转阿法替尼耐药治疗EGFR20外显子插入突变晚期非小细胞肺癌1例

恶性肿瘤严重威胁人们的生命健康,尤其是肺癌。随着对肺癌分子生物学的深入研究以及相关靶向药物的开发,靶向治疗已经改变了晚期肺癌的治疗格局。目前肺癌靶向治疗耐药机制成为研究的热点。本文报道1例阿帕替尼逆转经阿法替尼治疗耐药的表皮生长因子受体(epidermal growth factor receptor-tyrosine kinase,EGFR)20外显子插入突变晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者的治疗过程,并做文献复习。     

Audit of Molecular Mechanisms of Primary and Secondary Resistance to Various Generations of Tyrosine Kinase Inhibitors in Known Epidermal Growth Factor Receptor-Mutant Non-small Cell Lung Cancer Patients in a Tertiary Centre

AimsPresently, three generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are approved against oncogene addicted EGFR-mutant non-small cell lung cancer (NSCLC). Patients with actionable EGFR mutations invariably develop resistance. This resistance can be intrinsic (primary) or acquired (secondary).Materials and methodsThis was a retrospective study carried out between January 2016 and April 2021 analysing 486 samples of NSCLC for primary and secondary resistance to first- (erlotinib, gefitinb), second- (afatinib) and/or third-generation (osimertinib) TKIs in EGFR-mutant NSCLCs by next generation sequencing (NGS). Tissue NGS was carried out using the Thermofischer Ion Torrent? Oncomine? Focus 52 gene assay; liquid biopsy NGS was carried out using the Oncomine Lung Cell-Free Total Nucleic Acid assay. All cases were previously tested for a single EGFR gene with the Therascreen® EGFR RGQ PCR kit.ResultsThe results were divided into four groups: (i) group 1: primary resistance to first- and/or second-generation TKIs. This group, with 21 cases, showed EGFR exon 20 insertions, dual, complex mutations and variant of unknown significance, de novo MET gene amplification besides other mutations. (ii) Group 2: primary resistance to third-generation TKIs. This group showed two cases, with one showing dual EGFR mutation (L858R and E709A) and EGFR gene amplification. (iii) Group 3: secondary resistance to first- and second-generation TKIs. This group had 27 cases, which were previously reported negative for EGFR T790M by single gene testing. Significant findings were MET gene amplification in four cases, with one also showing MET exon 14 skipping mutation. Three cases showed small cell change and one showed loss of primary mutation. (iv) Group 4: secondary resistance to third-generation TKIs. The latter group was further subgrouped into group 4A: secondary resistance to osimertinib (third-generation TKI) when offered as second-line therapy after first- and second-generation TKIs on detection of T790M mutation. This group had 15 cases. EGFR T790M mutation was lost in 10 (10/15; 67%) cases and was retained in five cases. Patients with T790M loss experienced early resistance (6.9 months versus 12.6 months mean, P = 0.0024) compared with cases that retained T790M. Two cases gained MET amplification as the resistance mechanisms. Other mutations that were found when EGFR T790M was lost were in FGFR3, KRAS, PIK3CA, CTNNB1, BRAF genes. One case had EML4-ALK translocation. Two cases showed driver EGFR deletion 19, retained T790M and C797S mutation in Cis form. Group 4B: secondary resistance to osimertinib (when given as first-line therapy) in EGFR-mutant NSCLC. This group had three cases. The duration of osimertinib treatment ranged from 11 to 17 months. Two patients showed additional C797S mutation along with primary EGFR mutation.ConclusionThis study shows the wide spectrum of primary and secondary EGFR resistance mechanisms to first, second and third generation of TKIs and helps us to identify newer therapeutic targets that could carry forward the initial advantage offered by EGFR TKIs.     

A combination of gefitinib and FOLFOX-4 as first-line treatment in advanced colorectal cancer patients. A GISCAD multicentre phase II study including a biological analysis of EGFR overexpression, amplification and NF-kB activation

Interesting activity has been reported by combining chemotherapy with cetuximab. An alternative approach for blocking EGFR function has been the development of small-molecule inhibitors of tyrosine kinase domain such as gefitinib. We designed a multicentre phase II study in advanced colorectal cancer combining gefitinib+FOLFOX in order to determine the activity and to relate EGFR expression and gene amplification and NF-kB activation to therapeutic results. Patients received FOLFOX-4 regimen plus gefitinib as first-line treatment. Tumour samples were analysed for EGFR protein expression by immunohistochemical analysis and for EGFR gene amplification by fluorescence in situ hybridisation (FISH), chromogenic in situ hybridisation (CISH) and NF-kB activation. Forty-three patients were enrolled into this study; 15 patients experienced a partial response (response rate=34.9%), whereas other 12 (27.9%) had a stable disease. Median progression-free survival (PFS) was 7.8 months and median overall survival (OS) was 13.9 months. We did not find any relationship with EGFR overexpression, gene amplification, while NF-kB activation was associated with a resistance to therapy. Gefitinib does not seem to increase the activity of FOLFOX in advanced colorectal cancer even in patients overexpressing EGFR or with EGFR amplification. Furthermore, while NF-kB activation seems to predict resistance to chemotherapy as demonstrated 'in vitro' models, gefitinib does not overcome this mechanism of resistance, as reported for cetuximab.     

An alternative inhibitor overcomes resistance caused by a mutation of the epidermal growth factor receptor

Mutations of the epidermal growth factor receptor (EGFR) gene have been identified in non-small cell lung cancer specimens from patients responding to anilinoquinazoline EGFR inhibitors. However, clinical resistance to EGFR inhibitor therapy is commonly observed. Previously, we showed that such resistance can be caused by a second mutation of the EGFR gene, leading to a T790M amino acid change in the EGFR tyrosine kinase domain and also found that CL-387,785, a specific and irreversible anilinoquinazoline EGFR inhibitor, was able to overcome this resistance on the biochemical level. Here, we present the successful establishment of a stable Ba/F3 cell line model system for the study of oncogenic EGFR signaling and the functional consequences of the EGFR T790M resistance mutation. We show the ability of gefitinib to induce growth arrest and apoptosis in cells transfected with wild-type or L858R EGFR, whereas the T790M mutation leads to high-level functional resistance against gefitinib and erlotinib. In addition, CL-387,785 is able to overcome resistance caused by the T790M mutation on a functional level, correlating with effective inhibition of downstream signaling pathways. Similar data was also obtained with the use of the gefitinib-resistant H1975 lung cancer cell line. The systems established by us should prove useful for the large-scale screening of alternative EGFR inhibitor compounds against the T790M or other EGFR mutations. These data also support the notion that clinical investigations of compounds similar to CL-387,785 may be useful as a treatment strategy for patients with resistance to EGFR inhibitor therapy caused by the T790M mutation.     

Mutations of the epidermal growth factor receptor gene in NSCLC patients

Mutations of the epidermal growth factor receptor (EGFR) in patients with non-small cell lung cancer (NSCLC) were identified by re-sequencing all exons of this gene to evaluate the frequencies of EGFR gene mutation and identify rare or novel EGFR mutations. A total of 55 NSCLC samples from 55 patients were included in the study. Genomic DNA was extracted and exons 1-28 of the EGFR gene were sequenced to identify mutations. The cDNA of the EGFR gene with P848L and T790M double mutants was constructed by introducing point mutations into the wild-type EGFR vector using a site-directed mutagenesis kit. Among the 55 patients with NSCLC, 8 patients carried mutations of the EGFR gene. Notably, of the mutation-harboring patients with a pathological type of adenocarcinoma, 6 were non-smokers. The in vitro study demonstrated that the P848L mutant had a similar response to that of the wild-type EGFR after gefitinib treatment, and the P848L and T790M double mutant exhibited high resistance to gefitinib. These EGFR mutations preferentially occurred in lung adenocarcinoma patients, most of whom were non-smokers. In the in vitro study, P848L mutant EGFR had a similar response as the wild-type EGFR to gefitinib treatment, suggesting that lung cancer patients with a rare mutation of EGFR, such as the P848L mutation, do not respond to gefitinib treatment.     

Epidermal growth factor receptor (EGFR) is an independent adverse prognostic factor in esophageal adenocarcinoma patients treated with cisplatin-based neoadjuvant chemotherapy

Neoadjuvant platin-based therapy is accepted as a standard therapy for advanced esophageal adenocarcinoma (EAC). Patients who respond have a better survival prognosis, but still a significant number of responder patients die from tumor recurrence. Molecular markers for prognosis in neoadjuvantly treated EAC patients have not been identified yet. We investigated the epidermal growth factor receptor (EGFR) in prognosis and chemotherapy resistance in these patients. Two EAC patient cohorts, either treated by neoadjuvant cisplatin-based chemotherapy followed by surgery (n=86) or by surgical resection (n=46) were analyzed for EGFR protein expression and gene copy number. Data were correlated with clinical and histopathological response, disease-free and overall survival.In case of EGFR overexpression, the prognosis for neoadjuvant chemotherapy responders was poor as in non-responders. Responders had a significantly better disease-free survival than non-responders only if EGFR expression level (p=0.0152) or copy number (p=0.0050) was low. Comparing neoadjuvantly treated patients and primary resection patients, tumors of non-responder patients more frequently exhibited EGFR overexpression, providing evidence that EGFR is a factor for indicating chemotherapy resistance.EGFR overexpression and gene copy number are independent adverse prognostic factors for neoadjuvant chemotherapy-treated EAC patients, particularly for responders. Furthermore, EGFR overexpression is involved in resistance to cisplatin-based neoadjuvant chemotherapy.     

吉非替尼在非小细胞肺癌治疗中的继发耐药

吉非替尼是一种表皮生长因子受体(EGFR)酪氨酸激酶抑制剂,对非小细胞肺癌(NSCLC)有良好的抗肿瘤活性,但大多数患者最终因继发耐药出现病情进展.在发生EGFR基因突变的肺腺癌患者中,约半数吉非替尼继发耐药与二次突变有关,这种二次突变导致EGFR 790位上的苏氨酸被甲硫氨酸所取代(T790M).其他导致耐药的机制包括EGFR受体的内化现象以及MET基因扩增.     

Breast cancer resistance protein (BCRP) affected acquired resistance to gefitinib in a "never-smoked" female patient with advanced non-small cell lung cancer

Development of acquired resistance to gefitinib after an initial good response is common. Recently, it was reported that this acquired resistance is related to a secondary mutation associated with a substitution of threonine by methionine at codon 790 (T790M) of the epidermal growth factor receptor (EGFR) gene. In this report, we present a "never smoking" woman with advanced lung cancer who showed acquired resistance to gefitinib, and analysis of autopsy samples revealed no evidence of EGFR mutations in either exons 18-21 or codon 790, and positive immunostaining for breast cancer resistance protein (BCRP). We describe, for the first time, a case in which expression of BCRP was associated with acquired resistance to gefitinib, independent of EGFR mutations.     

Ligand‐triggered resistance to molecular targeted drugs in lung cancer: Roles of hepatocyte growth factor and epidermal growth factor receptor ligands

Recent advances in molecular biology have led to the identification of new molecular targets, such as epidermal growth factor receptor ( EGFR ) mutations and echinoderm microtubule‐associated protein‐like 4 (EML4) – anaplastic lymphoma kinase (ALK) fusion gene, in lung cancer. Dramatic response has been achieved with EGFR inhibitors (gefitinib and erlotinib) and an ALK inhibitor (crizotinib) in lung cancer expressing corresponding targets. However, cancer cells acquire resistance to these drugs and cause recurrence. Known major mechanisms for resistance to molecular targeted drugs include gatekeeper mutations in the target gene and activation of bypass survival signal via receptors other than the target receptors. The latter mechanism can involve receptor gene amplification and ligand‐triggered receptor activation as well. For example, hepatocyte growth factor (HGF), the ligand of a tyrosine kinase receptor Met, activates Met and the downstream PI3K/Akt pathway and triggers resistance to EGFR inhibitors in EGFR mutant lung cancer cells. Moreover, EGFR ligands activate EGFR and downstream pathways and trigger resistance to crizotinib in EML4‐ALK lung cancer cells. These observations indicate that signals from oncogenic drivers (EGFR signaling in EGFR ‐mutant lung cancer and ALK signaling in EML4‐ALK lung cancer) and ligand‐triggered bypass signals (HGF‐Met and EGFR ligands‐EGFR, respectively) must be simultaneously blocked to avoid the resistance. This review focuses specifically on receptor activation by ligand stimulation and discusses novel therapeutic strategies that are under development for overcoming resistance to molecular targeted drugs in lung cancer. (Cancer Sci 2012; 103: 1189–1194)     

EGFR mutation status in pleural fluid predicts tumor responsiveness and resistance to gefitinib

It has been reported that the threonine-to-methionine substitution at amino acid position 790 (T790M) of the epidermal growth factor receptor (EGFR) gene is correlated with acquired resistance to gefitinib. We previously reported that there was some population that harbored the EGFR T790M mutation as a minor clone of tumor cells prior to drug treatment, may be causing resistance to gefitinib during treatment. This fact also suggests that the detection of the EGFR T790M mutation prior to treatment may predict the development of resistance. We also showed that pleural fluid is a useful specimen for detection of EGFR mutation using sensitive assays. In this study, we reported a female patient who was treated with gefitinib because an EGFR L858R mutation was found in her pleural fluid. Our patient showed partial response to gefitinib, but she had progressive disease only 4 months after the start of treatment. Furthermore, the EGFR T790M mutation was detected in the pleural fluid before gefitinib treatment by the mutant-enriched PCR assay. Our findings confirmed that the EGFR T790M mutation was occasionally present as a minor population in tumor cells before treatment and caused resistance after gefitinib administration. The detection of a small fraction of T790M-positive alleles may be useful to predict the clinical course of the gefitinib-treated non-small-cell lung cancer patients.     

EGFR基因突变与吉非替尼的疗效和获得性耐药关系的研究概况

肿瘤的分子靶向治疗是近年发展起来的一种全新的治疗手段。吉非替尼（Gefitinib）是晚期非小细胞肺癌（NSCLC）治疗中的第1个靶向药物,具有特异性强,起效快,不良反应少的特点。其作用机制是抑制表皮生长因子受体（EGFR）酪氨酸激酶的活性,阻断EGFR生成信号传递至细胞内,从而抑制肿瘤细胞的异常增生和转移。临床疗效与EGFR基因的突变具有一定的相关性。EGFR基因突变有外显子19碱基缺失,外显子20的点突变或碱基插入突变和外显子21的点突变3种类型。其中外显子20的点突变可能是肿瘤细胞对Gefitinib产生抗药性的原因。EGFR基因的突变在东方人群,女性,腺癌和非吸烟人群中高表达,而且临床应用中已经证实Gefitinib在上述人群中有效率最高。EGFR基因在应用Gefitinib的过程中亦会发生二次突变,这可能是Gefitinib获得性耐药的机制,但亦有研究显示Gefitinib的耐药与药物的转运、EGFR基因的扩增以及信号通路的改变有关,非单一机制能完全解释其耐药性。所以如何利用EGFR来准确预测Gefitinib的有效性,预防和阻止Gefitinib耐药将是今后对EGFR和Gefitinib研究的重点。