肿瘤靶向性近红外荧光染料在PDX模型活体成像中的应用及相关机制

The patient derived xenograft (PDX) models generated by direct transplant of fresh human tumor tissue to nude mice maintain the original tumor heterogeneity, but it is difficult to monitor dynamically and short of sensitive and specific screening method to evaluate this model. Although the near infrared fluorescent dye (NIRF) can be realized for real time monitoring of cancer cells, it needs to mark specific probe with this dye. The latest research and our previous work demonstrate that the passage tumor cell can be specifically recognized and absorbed by near-infrared heptamethine cyanine fluorescence (NIRF) dye, mediated by organic anion transporting peptides (OATP) and HIF1a. Due to oxygen deficiency and activation of HIF1a/OATP signaling is most common mechanism in tumor cells, which indicate that this dye can directly target tumor cell of PDX models via HIF1a/OATP signaling molecular. In this study, we will screen for tumor targeted strong, specific and security NIRF dye by different PDX model, further to test the ability of this dye and its chemically modified product binding to tumor cells through the blood brain barrier on intracranial glioma xenogragts model, thus to establish a NIRF vivo imaging technology to recognize tumor cells directly. Furthermore, the molecular mechanisms of tumor cells targeting recognition NIRF dye via HIF1a/OATP signaling molecular are demonstrated by siRNA interference, Western-blot and RT-PCR methods. Our research will provide a reliable experimental and theoretical evidence for NIRF dye extensive applying in preparation, screening and assessment of PDX tumor models.

来源于病人新鲜肿瘤组织的异种移植（PDX）模型较好的保持了原发肿瘤的特征，但动态监测困难，缺乏敏感特异的评估方法。虽然近红外荧光染料（NIRF）可实现对癌细胞的实时监测，但需要标记特异性探针。最新报道和我们研究发现七甲川化菁类NIRF 可通过OATP介导直接识别传代肿瘤细胞，并与HIF1a表达相关。由于大部分肿瘤细胞普遍存在活化的HIF1a/OATP分子，推测NIRF通过该分子信号可直接靶向识别PDX模型肿瘤细胞。本课题拟通过PDX模型，筛选肿瘤靶向性强、特异安全的NIRF，通过脑胶质瘤原位模型近一步测试NIRF及其化学修饰产物通过血脑屏障结合肿瘤细胞的能力，从而建立直接靶向识别肿瘤的NIRF活体成像技术；应用siRNA、Western-blot和RT-PCR技术阐明HIF1a/OATP分子调控肿瘤细胞靶向NIRF的机制，为NIRF广泛应用于PDX模型的制备、筛查和评估提供实验和理论依据。

来源于病人新鲜肿瘤组织的异种移植（PDX）模型较好的保持了原发肿瘤的特征，但动态监测困难，缺乏敏感特异的评估方法。最新报道和我们研究发现七甲川花菁类近红外荧光（NIRF）染料可通过OATP介导直接识别传代肿瘤细胞，并与HIF1a表达相关。由于大部分肿瘤细胞普遍存在活化的HIF1a/OATP分子，推测NIRF通过该分子信号可直接靶向识别PDX模型肿瘤细胞。本课题先后建立了60多例人体肿瘤PDX模型，涉及胃癌、肝癌、胰腺癌和脑胶质瘤，模拟临床病人特征分别建立了雄激素依赖（HNPC）和雄激素抵抗（CRPC）前列腺癌PDX模型。筛选出肿瘤靶向性强、特异性和安全性高的NIRF染料DZ-1，通过肝癌PDX模型和细胞移植模型测试了NIRF染料及其化学修饰产物NIRG用于肿瘤活体成像和治疗的效果，通过脑胶质瘤原位模型进一步测试NIRF染料和NIRG通过血脑屏障结合肿瘤细胞的能力，从而建立直接靶向识别肿瘤的NIRF活体成像技术；分别采用siRNA，RT-PCR和IHC技术，实验证实OATP1B3参与引导DZ-1在裸鼠人胃癌PDX模型中的靶向性吸收；OATP3A1参与肝癌细胞对DZ-1的吸收，从而为NIRF染料广泛应用于不同类型PDX模型的制备、筛查和评估提供了实验和理论依据。同时，将NIRF染料标记核素68Ga实现NIR/PET双模态成像检测肝癌原位移植模型，从而为NIRF染料的临床非侵入性成像提供了实验数据。