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免疫治疗已成为多种恶性肿瘤的一线治疗方法,程序性细胞死亡受体1(programmed cell death 1 receptor,PD-1)和程序性细胞死亡配体1(programmed cell death 1 ligand,PD-L1)是目前临床应用最为成熟的免疫抑制剂,其通过抗体靶向结合免疫检查点,增强抗肿瘤免疫,从而延长患者的生存期[1-2],然而仅有部分患者临床获益。有研究结果显示,恶性肿瘤PD-1/PD-L1的表达水平是患者临床获益的影响因素之一[3-4]。因此,寻找一种高灵敏度和高特异度的方法检测PD-1/PD-L1的表达非常必要。靶向PD-1/PD-L1放射性核素分子探针显像可实时、无创、动态地监测肿瘤的靶向放射性核素分布、结合效率和在体内的特异性细胞生物学行为,为患者筛选、疗效监测、治疗方案优化和预后评估提供了新策略[5]。
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目前评估恶性肿瘤患者治疗疗效最常用的方法是通过免疫组织化学(immunohistochemistry, IHC)方法检测肿瘤细胞和肿瘤浸润T细胞PD-1/PD-L1的表达水平,从而有助于筛选受益患者[14]。Wang等[4]的研究结果显示,根据IHC检查结果,PD-L1阳性表达肿瘤的应答率为48%,而PD-L1阴性表达肿瘤的应答率为15%,这表明IHC检查并不能十分精准地评估恶性肿瘤的治疗疗效。IHC检查是一种有创性检查方法,且不同品牌抗体的使用以及在IHC检查过程中存在的各种系统性差异导致PD-1/PD-L1的表达阈值不同[15]。另外,PD-1/PD-L1的表达受干扰素、缺氧和前期治疗的影响,因此,在治疗过程中IHC检查难以对PD-1/PD-L1的表达水平进行动态监测 [16]。利用放射性核素标记完整单抗和抗体片段等制成靶向PD-1/PD-L1放射性核素分子探针进行显像,可提供全身甚至肿瘤微环境的完整图像,无创、实时、动态地监测PD-1/PD-L1的表达并量化其表达水平,可作为临床指导和疗效随访的重要方法。
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2015年,Heskamp等[17]首次使用111In标记人源单抗PD-L1.3.1,对乳腺癌异种移植鼠模型进行SPECT/CT显像,结果显示,111In-PD-L1.3.1在肿瘤中分布不均匀,该研究作为免疫治疗抗体的第1次核素标记研究,证明了利用放射性核素显像技术检测PD-L1表达的可能性,为靶向PD-L1放射性核素分子探针显像的研究奠定了基础。放射性核素标记单抗的优点是其与PD-1/PD-L1结合的亲和性强、制备方法简单;缺点是分子量大、体内半衰期过长、显像所需时间长且肿瘤穿透性差[17-24]。Niemejer等[25]首次报道了人体靶向PD-1/PD-L1的免疫显像研究,将18F-BMS-986192和89Zr-Nivolumab(纳武单抗)用于17例晚期非小细胞肺癌患者治疗前后的全身PET/CT显像,结果显示,在不同患者及同一患者的不同肿瘤病灶之间,肿瘤对显像剂的摄取具有明显的异质性。多项关于放射性核素标记单抗显像的研究结果显示,由于单抗的生物半衰期较长,主要使用111In、64Cu等中长半衰期放射性核素标记,均证明了放射性核素标记单抗显像具有无限可能[17-29]。相关放射性核素标记单抗SPECT显像和PET显像的具体内容见表1、2。
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Heskamp等[17] 111In-PD-L1.3.1 乳腺癌 PD-L1高表达的肿瘤高摄取,且在肿瘤内分布不均匀 2016 Chatterjee等[18] 111In-atezolizumab 卵巢癌、
前列腺癌、
非小细胞肺癌PD-L1高表达的肿瘤高摄取,证明111In-atezolizumab与PD-L1在体内结合具有特异性 2017 Nedrow等[19] 111In-DTPA-anti-PD-L1 黑色素瘤
注射111In-DTPA-anti-PD-L1 72 h后,在肿瘤中的分布达到峰值2019 Heskamp等[20] 111In-anti-mPD-L1 乳腺癌、
黑色素瘤、
结肠癌、
肾癌在microSPECT/CT显像中成功检测到具有免疫活性荷瘤小鼠的肿瘤PD-L1表达 注:SPECT为单光子发射计算机体层摄影术;PD-L1.3.1为一种人源单抗;atezolizumab 为阿特朱单抗;DTPA为二乙基三胺五乙酸;PD-L1为程序性细胞死亡配体1;CT为计算机体层摄影术 表 1 2015~2019年放射性核素标记单抗SPECT显像相关文献的主要内容
Table 1. Main contents of relevant literature on SPECT imagings of radionuclide labeled monoclonal antibody in 2015−2018
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Natarajan等[21] 89Zr-keytruda、
64Cu-keytruda黑色素瘤 脾淋巴器官和肿瘤高摄取 2016 Hettich等[22] 64Cu-NOTA-PD-1、
64Cu-NOTA-PD-L1黑色素瘤 PD-L1高表达的肿瘤和棕色脂肪组织高摄取,提示其可能与免疫相关 2016 Lesniak等[23] 64Cu-atezolizumab 黑色素瘤 PD-L1高表达肿瘤的摄取明显高于PD-L1低表达肿瘤 2017 Kikuchi等[24] 89Zr-DFO-PD-L1 颈鳞状细胞癌、
黑色素瘤放疗可上调PD-L1的表达,受照射肿瘤高摄取 2018 Niemeijer等[25] 18F-BMS-986192、
89Zr-Nivolumab非小细胞肺癌 肿瘤对显像剂的摄取具有明显异质性 2019 Jagoda等[26] 89Zr-DFO-PD-L1 乳腺癌 89Zr-DFO-PD-L1在体外对PD-L1具有特异性和高亲和力,其在体内具有与PD-L1表达相关的靶组织摄取 2019 Vento等[27] 89Zr-atezolizumab 转移性肾透明细胞癌 摄取明显高于对照肿瘤移植物,允许对治疗干预进行动态评估 2020 Christensen等[28] 89Zr-DFO-6E11 非小细胞肺癌 可检测放疗后PD-L1的表达水平,从而预测PD-L1免疫抑制剂的反应 2020 Li等 [29] 89Zr-Df-avelumab 乳腺癌 注射后48 h,肿瘤、脾脏和淋巴结的摄取达到峰值,生物学分布与PET显像的定量数据一致 注:PET为正电子发射断层显像术;keytruda为帕博利单抗;NOTA为1,4,7-三氮杂环壬烷-1,4,7-三乙酸;PD-1为程序性细胞死亡受体1;PD-L1为程序性细胞死亡配体1;atezolizumab 为阿特朱单抗;DFO为去铁胺;BMS为一种实验性抗PD-L1抗体;Nivolumab为纳武单抗;Df为去铁酮;6E11为一种合成探针;avelumab为阿维单 表 2 2015~2020年放射性核素标记单抗PET显像相关文献的主要内容
Table 2. Main contents of relevant literature on PET imagings of radionuclide labeled monoclonal antibody in 2015−2020
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近年来,因sdAb分子量低、在循环中能被快速清除且同时保持高靶结合力[30-32]的优势,使其在临床模型中表现出巨大的分子显像潜力。2019 年,Xing等[31]对17例非小细胞肺癌患者进行关于特异性结合人PD-L1的99Tcm-NM-01(一种99Tcm标记的sdAb)SPECT/CT显像的Ⅰ期临床试验,结果显示,99Tcm-NM-01 SPECT/CT显像可用于监测患者治疗期间肿瘤PD-L1表达水平的变化。相关放射性核素标记sdAb显像的具体内容见表3。
表 3 2018~2019年放射性核素标记sdAb显像相关文献的主要内容
Table 3. Main contents of relevant literature on radionuclide labeled sdAb imaging in 2018−2019
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Maute等[33]制备了PD-1胞外结构域的可溶性片段,并将其命名为高亲和力PD-1(HAC-PD-1),结果显示,其能特异性地拮抗PD-1/PD-L1的相互作用,疗效相当于PD-L1单抗;用64Cu标记高亲和力PD-1(HAC-PD-1),进行PET显像,可观察到肿瘤特异性高摄取,但仍需要更多的研究结果验证高亲和力PD-1(HAC-PD-1)作为治疗和免疫诊断的潜力。低分子量探针主要包括抗体片段、纳米抗体(nanobodies,Nbs)和多肽等,其具有强穿透性、高亲和力、高特异性、相对分子质量小、易于通过血脑屏障、可快速清除和辐射剂量较低等优点;缺点是制备方法复杂、稳定性差[34-40]。相关放射性核素标记低分子量探针显像的具体内容见表4。
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Maute等[33] 64Cu-HAC-PD-1 结肠癌 肿瘤特异性高摄取,其大小的增加不成比例地影响PD-L1抗体的效果 2017 Chatterjee等[34] 64Cu-WL12 卵巢癌、
乳腺癌PD-L1高表达的肿瘤摄取高于低表达的肿瘤 2017 Mayer[35] 64Cu-DOTA-HAC-PD-1
64Cu-NOTA-HAC-PD-1
64Cu-NOTA-HACA-PD-1
68Ga-NOTA-HAC-PD-1
68Ga-NOTA-HACA-PD-1
68Ga-DOTA-HACA-PD-1结肠癌 研究了6种HAC-PD-1放射性核素低分子量探针,可用于检测临床对基于免疫检查点的恶性肿瘤免疫治疗的反应 2017 Broos等[36] 99Tcm-Nbs 小鼠细胞系 99Tcm-Nbs在肿瘤中的摄取与PD-L1的表达直接相关 2018 Donnelly等[37] 18F-BMS-986192 非小细胞肺癌、
结肠癌PD-L1高表达的肿瘤摄取明显高于PD-L1低表达的肿瘤 2018 De等[38] 68Ga-WL12 卵巢癌、
乳腺癌PD-L1高表达的肿瘤摄取高于PD-L1低表达的肿瘤 2020 Lv等[39] 68Ga-NOTA-Nb109
68Ga-NOTA-Nb109乳腺癌 PD-L1高表达的荷瘤小鼠肿瘤摄取高 2020 Gao等[40] 99Tcm-MY1523 结肠癌、B细胞
淋巴瘤、
乳腺癌对体内PD-L1的表达进行活体组织病理学检查,揭示了上调PD-L1表达与PD-L1阻断治疗之间的相关性 注:HAC为高亲和力的;PD-1为程序性细胞死亡受体1;PD-L1为程序性细胞死亡配体1;WL12为一种抗体试验试剂;DOTA为1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸;NOTA为1,4,7-三氮杂环壬烷-1,4,7-三乙酸;HACA为人抗嵌合抗体;Nbs为纳米抗体;BMS为一种实验性抗PD-L1抗体;MY1523为一种99Tcm标记的抗PD-L1纳米抗体 表 4 2015~2020年放射性核素标记低分子量探针显像相关文献的主要内容
Table 4. Main contents of relevant literature on radionuclide labeled low molecular weight probe imaging in 2015−2020
靶向PD-1/PD-L1放射性核素分子探针及其在恶性肿瘤中的应用
Targeted PD-1/PD-L1 radionuclde molecular probes and its application in malignant tumors
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摘要: 程序性细胞死亡受体1(PD-1)及其配体(PD-L1)免疫治疗已成为一种治疗多种恶性肿瘤的重要方法,但仅有部分患者临床获益,其影响因素之一是恶性肿瘤PD-1/PD-L1的表达水平。使用放射性核素标记完整单克隆抗体和抗体片段等制成靶向PD-1/PD-L1放射性核素分子探针进行显像,可无创、实时、动态地监测肿瘤PD-1/PD-L1的表达并量化其表达水平,进而筛选适宜治疗的患者、全面评估治疗疗效和预后。笔者综述了靶向PD-1/PD-L1放射性核素分子探针及其在恶性肿瘤中的应用。
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关键词:
- 放射性核素显像 /
- 分子探针 /
- 程序性细胞死亡受体1 /
- B7-H1抗原 /
- 肿瘤
Abstract: Programmed cell death 1 receptor (PD-1) and its ligand (PD-L1) immunotherapy has become an important method for the treatment of a variety of malignant tumors, but only some patients have clinical benefits. One of the influencing factors is the expression level of PD-1/PD-L1 in malignant tumors. Radionuclide labeled complete monoclonal antibodies and antibody fragments are used to make targeted PD-1/PD-L1 radionuclide molecular probes for imaging, which can noninvasively, real-time, and dynamically monitor the expression of tumor PD-1/PD-L1 and quantify its expression level, so as to screen patients suitable for treatment and comprehensively evaluate the treatment efficacy and prognosis. The authors review the application of targeted PD-1/PD-L1 radionuclide molecular probes in malignant tumors.-
Key words:
- Radionuclide imaging /
- Molecular probes /
- Programmed cell death 1 receptor /
- B7-H1 antigen /
- Neoplasms
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表 1 2015~2019年放射性核素标记单抗SPECT显像相关文献的主要内容
Table 1. Main contents of relevant literature on SPECT imagings of radionuclide labeled monoclonal antibody in 2015−2018
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Heskamp等[17] 111In-PD-L1.3.1 乳腺癌 PD-L1高表达的肿瘤高摄取,且在肿瘤内分布不均匀 2016 Chatterjee等[18] 111In-atezolizumab 卵巢癌、
前列腺癌、
非小细胞肺癌PD-L1高表达的肿瘤高摄取,证明111In-atezolizumab与PD-L1在体内结合具有特异性 2017 Nedrow等[19] 111In-DTPA-anti-PD-L1 黑色素瘤
注射111In-DTPA-anti-PD-L1 72 h后,在肿瘤中的分布达到峰值2019 Heskamp等[20] 111In-anti-mPD-L1 乳腺癌、
黑色素瘤、
结肠癌、
肾癌在microSPECT/CT显像中成功检测到具有免疫活性荷瘤小鼠的肿瘤PD-L1表达 注:SPECT为单光子发射计算机体层摄影术;PD-L1.3.1为一种人源单抗;atezolizumab 为阿特朱单抗;DTPA为二乙基三胺五乙酸;PD-L1为程序性细胞死亡配体1;CT为计算机体层摄影术 表 2 2015~2020年放射性核素标记单抗PET显像相关文献的主要内容
Table 2. Main contents of relevant literature on PET imagings of radionuclide labeled monoclonal antibody in 2015−2020
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Natarajan等[21] 89Zr-keytruda、
64Cu-keytruda黑色素瘤 脾淋巴器官和肿瘤高摄取 2016 Hettich等[22] 64Cu-NOTA-PD-1、
64Cu-NOTA-PD-L1黑色素瘤 PD-L1高表达的肿瘤和棕色脂肪组织高摄取,提示其可能与免疫相关 2016 Lesniak等[23] 64Cu-atezolizumab 黑色素瘤 PD-L1高表达肿瘤的摄取明显高于PD-L1低表达肿瘤 2017 Kikuchi等[24] 89Zr-DFO-PD-L1 颈鳞状细胞癌、
黑色素瘤放疗可上调PD-L1的表达,受照射肿瘤高摄取 2018 Niemeijer等[25] 18F-BMS-986192、
89Zr-Nivolumab非小细胞肺癌 肿瘤对显像剂的摄取具有明显异质性 2019 Jagoda等[26] 89Zr-DFO-PD-L1 乳腺癌 89Zr-DFO-PD-L1在体外对PD-L1具有特异性和高亲和力,其在体内具有与PD-L1表达相关的靶组织摄取 2019 Vento等[27] 89Zr-atezolizumab 转移性肾透明细胞癌 摄取明显高于对照肿瘤移植物,允许对治疗干预进行动态评估 2020 Christensen等[28] 89Zr-DFO-6E11 非小细胞肺癌 可检测放疗后PD-L1的表达水平,从而预测PD-L1免疫抑制剂的反应 2020 Li等 [29] 89Zr-Df-avelumab 乳腺癌 注射后48 h,肿瘤、脾脏和淋巴结的摄取达到峰值,生物学分布与PET显像的定量数据一致 注:PET为正电子发射断层显像术;keytruda为帕博利单抗;NOTA为1,4,7-三氮杂环壬烷-1,4,7-三乙酸;PD-1为程序性细胞死亡受体1;PD-L1为程序性细胞死亡配体1;atezolizumab 为阿特朱单抗;DFO为去铁胺;BMS为一种实验性抗PD-L1抗体;Nivolumab为纳武单抗;Df为去铁酮;6E11为一种合成探针;avelumab为阿维单 表 3 2018~2019年放射性核素标记sdAb显像相关文献的主要内容
Table 3. Main contents of relevant literature on radionuclide labeled sdAb imaging in 2018−2019
表 4 2015~2020年放射性核素标记低分子量探针显像相关文献的主要内容
Table 4. Main contents of relevant literature on radionuclide labeled low molecular weight probe imaging in 2015−2020
发表时间(年) 研究者[文献] 放射性核素分子探针 恶性肿瘤 主要结果 2015 Maute等[33] 64Cu-HAC-PD-1 结肠癌 肿瘤特异性高摄取,其大小的增加不成比例地影响PD-L1抗体的效果 2017 Chatterjee等[34] 64Cu-WL12 卵巢癌、
乳腺癌PD-L1高表达的肿瘤摄取高于低表达的肿瘤 2017 Mayer[35] 64Cu-DOTA-HAC-PD-1
64Cu-NOTA-HAC-PD-1
64Cu-NOTA-HACA-PD-1
68Ga-NOTA-HAC-PD-1
68Ga-NOTA-HACA-PD-1
68Ga-DOTA-HACA-PD-1结肠癌 研究了6种HAC-PD-1放射性核素低分子量探针,可用于检测临床对基于免疫检查点的恶性肿瘤免疫治疗的反应 2017 Broos等[36] 99Tcm-Nbs 小鼠细胞系 99Tcm-Nbs在肿瘤中的摄取与PD-L1的表达直接相关 2018 Donnelly等[37] 18F-BMS-986192 非小细胞肺癌、
结肠癌PD-L1高表达的肿瘤摄取明显高于PD-L1低表达的肿瘤 2018 De等[38] 68Ga-WL12 卵巢癌、
乳腺癌PD-L1高表达的肿瘤摄取高于PD-L1低表达的肿瘤 2020 Lv等[39] 68Ga-NOTA-Nb109
68Ga-NOTA-Nb109乳腺癌 PD-L1高表达的荷瘤小鼠肿瘤摄取高 2020 Gao等[40] 99Tcm-MY1523 结肠癌、B细胞
淋巴瘤、
乳腺癌对体内PD-L1的表达进行活体组织病理学检查,揭示了上调PD-L1表达与PD-L1阻断治疗之间的相关性 注:HAC为高亲和力的;PD-1为程序性细胞死亡受体1;PD-L1为程序性细胞死亡配体1;WL12为一种抗体试验试剂;DOTA为1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸;NOTA为1,4,7-三氮杂环壬烷-1,4,7-三乙酸;HACA为人抗嵌合抗体;Nbs为纳米抗体;BMS为一种实验性抗PD-L1抗体;MY1523为一种99Tcm标记的抗PD-L1纳米抗体 -
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