131I WBS阴性/Tg阳性分化型甲状腺癌复发或转移灶NIS与GLUT表达的相关性研究

Local recurrence and distant metastases are common in differentiated thyroid carcinoma (DTC) after surgery. Metastatic disease is a factor that worsens prognosis of DTC patients. Therefore, the long-term monitoring of patients with DTC is essential throughout the patient's life after total or nearly total thyroidectomy followed by iodine-131 remnant ablation and thyroid hormone suppression of thyroid-stimulating hormone (TSH). Sensitive surveillance for DTC recurrences and metastases includes radioiodine diagnostic whole-bodyscanning (DWBS) and measurement of serum thyroglobulin (Tg) levels after endogenous or exogenous TSH stimulation. Serum Tg levels during thyroid hormone withdrawal usually are correlated well with the results of DWBS. However, differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases (131IWBS-/Tg+) has been observed in follow-up studies. To treat or not to treat these patients who have 131IWBS-/Tg+ metastases with radioiodine remains controversial. Our previous studies have found that the abnormal expression and the functional integrity of sodium/iodine symporter (NIS) attribute to 131IWBS-/Tg+. We also observed that 18FDG-PET has limited value in the diagnosis of DTC with 131IWBS-/Tg+, and the flip-flop phenomena of 18FDG and iodine-131 uptake, an inverse relationship was found between uptake of 18FDG and iodine-131 in most DTC metastases, a phenomenon termed "flip-flop"-namely, functional tumor differentiation is associated with low 18F-FDG uptake and retaining iodine-131 uptake, whereas dedifferentiation is associated with the loss of iodine-accumulating ability and an increase in metabolism from progressive growth. Currently no study on the expression of glucose transporter (GLUT) and TSH was reported. To improve 18FDG-PET imaging and develop new target imaging agent, study on NIS, GLUT and TSH in 131IWBS-/Tg+ lesions is necessary. Based on the previous studies the project aims to: ⑴. Investigate the correlation between the expression of GLUT and NIS and TSH for the understanding of the flip-flop phenomena of 18FDG and 131I uptake. ⑵. Explain the role of the 18FDG-PET in the diagnosis of DTC with 131IWBS-/Tg+. ⑶. Analyze the FDG uptake difference in DTC and 131IWBS-/Tg+ metastases, and the correlation between GLUT and TSH.

分化型甲状腺癌(DTC)易复发或转移，严重影响生命健康，必须定期进行131IWBS和Tg两种主要的随访检查。10-15% DTC出现131IWBS-/Tg+，这是最为棘手的临床问题，因为只有定性诊断而无定位依据，尤其不能进行131I治疗。前期研究分析131IWBS-/Tg+与NIS表达异常有关；18FDG-PET显像诊断特异性不高；18FDG和131I的摄取不一致；缺乏葡萄糖转运体（GLUT）表达及其TSH调控的体内研究。本项目在上述前期研究基础上，进行NIS、GLUT表达和TSH相关性研究，以了解和阐明131IWBS-/Tg+病灶葡萄糖与碘代谢的反转现象的分子机制、18FDG-PET显像阴性和阳性的原因、DTC以及131IWBS-/Tg+ 病灶摄取FDG机制差异以及与GLUT亚型、TSH相关性，为改进18FDG-PET显像方法和开发靶向显像剂提供理论依据，并为DTC治疗和预后提供评判标准

背景：分化型甲状腺癌(DTC)易复发或转移，131IWBS和Tg是其两种主要的随访检查方法。临床中约10-15% DTC出现131I WBS显像阴性而Tg阳性（131I WBS-/Tg+），这是最为棘手的临床问题。对这部分病人的诊断和治疗是临床上较为棘手的问题。前期研究分析131IWBS-/Tg+病灶葡萄糖和碘代谢相关。基于此，本项目主要对碘钠转运蛋白(NIS)、GLUT的表达和TSH进行了相关性研究。. 主要研究内容： 1.甲状腺癌细胞皮下注射和原位甲状腺注射法建立甲状腺癌模型,以及甲癌骨转移模型建立；2.131IWBS–/Tg+ DTC转移灶进行FDG PET/CT显像，并收集DTC转移灶标本，利用RT-PCR、免疫组化等方法检测NIS、GLUT、TSH受体的表达；3.TSH受体在失分化的DTC细胞株的表达，TSH受体转染与失分化DTC细胞株碘代谢研究；4.Notch1受体在DTC细胞中的表达，以及与肿瘤侵袭能力和进展的相关性研究；5.纳米胶囊靶向治疗131IWBS–/Tg+ DTC转移灶的基础研究；6.对131IWBS–/Tg+ DTC转移灶进行整合素受体显像（18F-AIF-NOTA-PRGD2），并与18F-FDG PET/CT显像进行比较；7. DTC清甲剂量的研究。. 重要结果和关键数据及科学意义：成功建立DTC模型；DTC及其淋巴结转移灶、131IWBS–/Tg+ DTC转移灶中NIS表达无明显差异，DTC淋巴结转移灶GLUT4表达增加； 131IWBS–/Tg+ DTC转移灶中GLUT4表达增加，而NIS表达未见明显变化。该发现提示DTC病灶中，GLUT4在葡萄糖代谢中可能扮演比GLUT1更重要的角色，或者二者在TSH调控下存在差异表达。通过获取hTSHR目的基因片段、hTSHR慢病毒质粒的构建和包装，将hTHSR慢病毒质粒转染失分化的FTC-133细胞株后，可以明显上调碘相关蛋白的表达并提高细胞摄碘率。甲状腺乳头状癌（PTC）三种细胞株 BCPAP, K1, and TPC1中均有整合素受体的表达 （αvβ3 和 αvβ5）。RGD拮抗剂对这三种PTC细胞株均有抑制作用，其中以TPC1最明显。设计了牛血清白蛋白（BSA）纳米胶囊，有望利用蛋白纳米颗粒实现对131IWBS–/Tg+ DTC病灶靶向治疗。