錸-188標誌奈米微脂體於大鼠腦神經膠質腫瘤之診療評估

Theranostic Evaluation of 188Re-Labeled PEGylated Nanoliposome in Glioma Bearing Rat Model

黃蜂運(Feng-Yun Jimmy Huang)

指導教授 ： 羅建苗 ； 張建文

國立清華大學/原子科學院/生醫工程與環境科學系/博士(2015年)

https://doi.org/10.6843/NTHU.2015.00269

摘要

多型性膠質母細胞瘤（glioblastoma multiforme; GBM）及分化不良星狀細胞瘤（anaplastic astrocytoma; AA），為原發性中樞神經系統中最為常見之惡性神經膠質腫瘤（malignant gliomas）。惡性神經膠質腫瘤其高好發性及高致死性導致它被列為第4位嚴重具致死性的癌症。本研究中，首先製備聚乙二醇（polyethylene glycol; PEG）修飾之長循環錸-188標誌奈米微脂體（PEGylated 188Re-liposomes）藥物，並以原位形成大鼠腦神經膠質腫瘤（Fischer344/F98 or F98luc）進行診療（theranostics）評估。藥物透過單次尾靜脈注射進原位荷瘤大鼠後，其診斷性評估實驗包括有生物分佈、藥物動力學、自體放射顯像、組織病理學及單光子發射電腦斷層照影（SPECT/CT）；療效性評估實驗則包括有最大耐受劑量評估、體內輻射劑量學評估、生物冷光照影及療效評估等。
結果顯示，錸-188標誌奈米微脂體能藉由對腫瘤之通透性增強及停滯效應（enhanced permeability and retention effect; EPR effect）有效地累積於腦腫瘤位置，其藥物累積量自注射後1小時的0.28±0.09 %ID/g至24小時的1.95±0.35 %ID/g。進一步分析，腫瘤對正常腦組織的藥物攝取比（tumor-to-normal brain ratio; T/N ratio）自藥物注射後1小時的3.5倍至24小時的32.5倍。自動放射顯像及組織病理切片實驗皆證實藥物的累積具高T/N比。此外，藥物注射後的4小時至48小時，單光子發射電腦斷層照影可清楚呈現腦腫瘤之影像。於療效性相關實驗中，完成建立具生物冷光報導基因之大鼠腦神經膠質腫瘤細胞（F98luc），體外生物冷光表現顯示其細胞數量與生物冷光強度呈高線性正比關係（R2 = 0.99）。進一步於體內實驗顯示，生物冷光系統可有效作為非侵入式活體影像監控大鼠腦腫瘤之生長。最大耐受輻射劑量實驗顯示，大鼠對錸-188標誌奈米微脂體藥物最大容許活度值為333 MBq。療效評估顯示，相較於控制組（注射生理食鹽水），錸-188標誌奈米微脂體藥物治療之荷瘤大鼠其不僅能有效抑制腫瘤生長，並且能延長其荷瘤大鼠之存活率（10.67%）（P<0.05）。另外，體內輻射劑量學評估結果示，錸-188標誌奈米微脂體藥物除了在脾臟（6.96 mSv/MBq）及腎臟（1.20 mSv/MBq）有相對高的劑量累積外，其它危急器官如正常腦組織（2.75×10-2 mSv/MBq）、紅骨髓（5.13×10-2 mSv/MBq）、及甲狀腺（7.04×10-2 mSv/MBq）等皆顯示存在較低之輻射累積劑量。
總結，錸-188標誌奈米微脂體藥物應用於原位形成大鼠腦神經膠質腫瘤之診斷及治療評估已詳盡於本研究中完成。透過劑量學、存活率等療效性評估可清楚顯示，系統性施行錸-188標誌奈米微脂體藥物，其被動標靶至腫瘤特性能有意義延長荷瘤大鼠之存活期並維持系統之輻射劑量安全性。綜合以上研究結果，錸-188標誌奈米微脂體藥物可為一有潛力之診療性放射藥物，並且值得進一步發展作為臨床上治療惡性神經膠質腫瘤之藥劑。

關鍵字

錸-188 ； 微脂體 ； 多型性膠質母細胞瘤

並列摘要

Malignant glioma, including glioblastoma multiforme (GBM) and anaplastic astrocytoma (AA), is the most frequently relapsed cancer in the primary brain and central nervous system. High morbidity and mortality make it as the fourth most serious death-leading cancer worldwide. In this study, the 188Re-labeled PEGylated nanoliposomes (188Re-liposomes) were fabricated and evaluated as novel theranostic agents in an orthotopic glioma-bearing rat model (Fischer344/F98 or F98luc). The orthotopic glioma-bearing rats were carefully prepared and subsequently administered with 188Re-liposomes via single intravenous injection. Non-invasive bioluminescence imaging (BLI) was used to monitor tumor growth progress on Fischer344/F98luc model. For diagnostic evaluation, a series of experiments including biodistribution, pharmacokinetics, autoradiography, histopathology, and SPECT/CT imaging were conducted. A therapeutic evaluation, supported with pathological examination, was followed by monitoring the survivals of the 188Re-liposomes-treated rats together with non-treated group along with the reared time. Meanwhile, the dosimetry for the radiotherapeutic study was assessed.
It is indicated from the diagnostic study that 188Re-liposomes could be efficiently and increasingly accumulated in the brain tumor from 0.28±0.09 %ID/g at 1 h to a maximum of 1.95±0.35 %ID/g at 24 h postinjection, with the tumor-to-normal brain uptake ratio (T/N ratio) from 3.5 at 1 h to 32.5 at 24 h. Both autoradiography and histopathological examination gave correlative informations for the diagnostic study. In addition, the tumors implanted in the rats could be obviously observed via SPECT/CT imagings in the growth period from 4 h till 48 h.
For therapeutic study, the reporter cell line F98luc could afford a good relationship between the cell number and the bioluminescent intensity (R2 = 0.99) in vitro and the BLI could be used as a non-invasive imaging system to clearly monitor the brain tumor growth in vivo. It is demonstrated from the therapeutic study that the 188Re-liposomes-treated rats not only had the tumor growth inhibited but also had the survival with 10.67% prolonged as compared with the control group (treated with normal saline), with significance P<0.05. In dosimetry, the relative high radiation doses were found in the spleen (6.96 mSv/MBq) and kidney (1.20 mSv/MBq) whereas very less doses were found in the normal brain (2.75×10-2 mSv/MBq), red marrow (5.13×10-2 mSv/MBq), and thyroid (7.04×10-2 mSv/MBq); the maximum tolerated dose of 188Re-liposomes in Fischer344 rats was estimated to be 333 MBq.
In summary, this work has revealed the potentiality of the role of 188Re-liposomes acted as a theranostic pharmaceutical and it is worthy to further evaluate the agent clinically for brain tumor therapy.

並列關鍵字

188Re ； liposome ； glioblastoma multiforme

參考文獻

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