Slade Rozanna L, Pisaneschi Federica, Nguyen Quang-De, Smith Graham, Carroll Laurence, Beckley Alice, Kaliszczak Maciej A, Aboagye Eric O
Comprehensive Cancer Imaging Centre, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, United Kingdom.
PLoS One. 2016 Aug 23;11(8):e0161427. doi: 10.1371/journal.pone.0161427. eCollection 2016.
The epidermal growth factor receptor (EGFR) is overexpressed in many cancers including lung, ovarian, breast, head and neck and brain. Mutation of this receptor has been shown to play a crucial role in the response of non-small cell lung carcinoma (NSCLC) to EGFR-targeted therapies. It is envisaged that imaging of EGFR using positron emission tomography (PET) could aid in selection of patients for treatment with novel inhibitors. We recognised multi-drug resistant phenotype as a threat to development of successful imaging agents. In this report, we describe discovery of a novel cyanoquinoline radiotracer that lacks ABC transporter activity.
Cellular retention of the prototype cyanoquinoline 18F-N-{4-[(3-chloro-4-fluorophenyl)amino]-3-cyano-7-ethoxyquinolin-6-yl}-4-({[1-(2-fluoroethyl)-1H-1,2,3-triazol-4-yl]methyl}amino)-but-2-enamide ([18F]FED6) and 18F-N-{4-[(3-chloro-4-fluorophenyl)amino]-3-cyano-7-ethoxyquinolin-6-yl}-4-[({1-[(2R,5S)-3-fluoro-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]-1H-1,2,3-triazol-4-yl}methyl)amino]but-2-enamide ([18F]FED20) were evaluated to establish potential for imaging specificity. The substrate specificity of a number of cyanoquinolines towards ABC transporters was investigated in cell lines proficient or deficient in ABCB1 or ABCG2.
FED6 demonstrated substrate specificity for both ABCG2 and ABCB1, a property that was not observed for all cyanoquinolines tested, suggesting scope for designing novel probes. ABC transporter activity was confirmed by attenuating the activity of transporters with drug inhibitors or siRNA. We synthesized a more hydrophilic compound [18F]FED20 to overcome ABC transporter activity. FED20 lacked substrate specificity for both ABCB1 and ABCG2, and maintained a strong affinity for EGFR. Furthermore, FED20 showed higher inhibitory affinity for active mutant EGFR versus wild-type or resistant mutant EGFR; this property resulted in higher [18F]FED20 cellular retention in active mutant EGFR expressing NSCLC.
[18F]FED20 binds EGFR but is devoid of ABC transporter activity, thus, has potential for EGFR imaging.
表皮生长因子受体（EGFR）在包括肺癌、卵巢癌、乳腺癌、头颈癌和脑癌在内的多种癌症中过表达。已证明该受体的突变在非小细胞肺癌（NSCLC）对EGFR靶向治疗的反应中起关键作用。设想使用正电子发射断层扫描（PET）对EGFR进行成像有助于选择接受新型抑制剂治疗的患者。我们认识到多药耐药表型对成功开发成像剂构成威胁。在本报告中，我们描述了一种缺乏ABC转运蛋白活性的新型氰基喹啉放射性示踪剂的发现。
评估了原型氰基喹啉18F-N-{4-[(3-氯-4-氟苯基)氨基]-3-氰基-7-乙氧基喹啉-6-基}-4-({[1-(2-氟乙基)-1H-1,2,3-三唑-4-基]甲基}氨基)-丁-2-烯酰胺([18F]FED6)和18F-N-{4-[(3-氯-4-氟苯基)氨基]-3-氰基-7-乙氧基喹啉-6-基}-4-[({1-[(2R,5S)-3-氟-4,5-二羟基-6-(羟甲基)氧杂环己烷-2-基]-1H-1,2,3-三唑-4-基}甲基)氨基]丁-2-烯酰胺([18F]FED20)的细胞保留情况，以确定成像特异性的潜力。在ABCB1或ABCG2功能正常或缺陷的细胞系中研究了多种氰基喹啉对ABC转运蛋白的底物特异性。
FED6对ABCG2和ABCB1均表现出底物特异性，这一特性在所有测试的氰基喹啉中未观察到，表明设计新型探针具有空间。通过用药物抑制剂或小干扰RNA减弱转运蛋白的活性来证实ABC转运蛋白活性。我们合成了一种更具亲水性的化合物[18F]FED20以克服ABC转运蛋白活性。FED20对ABCB1和ABCG2均缺乏底物特异性，并对EGFR保持强亲和力。此外，FED20对活性突变型EGFR的抑制亲和力高于野生型或耐药突变型EGFR；这一特性导致[18F]FED20在表达活性突变型EGFR的NSCLC细胞中具有更高的细胞保留率。
[18F]FED20与EGFR结合但缺乏ABC转运蛋白活性，因此具有用于EGFR成像的潜力。
