中孔洞磁性氫氧基磷灰石做為合併化療和熱療之載體於肺癌之研究

Abstract

癌症為國人十大死因之首已蟬聯多年，在癌症的治療方法普遍為外科手術、放射療法及化學藥物療法，近年來隨著許多研究發現，也有一些新興的療法可以治療癌症並帶來較少的副作用，熱治療為目前相當熱門的研究之一，透過將組織升至42-47°C，癌細胞會死亡而正常細胞則不會。 本研究以合併化學療法和熱療為主題，利用本實驗室所開發的磁性氫氧基磷灰石(magnetic hydroxyapatite, mHAP)做為藥物載體，磁性氫氧基磷灰石為一生物相容性良好的材料，於共沉澱法加入蛋白經由高溫 (800°C) 脫碳後，可形成中孔洞 (mesoporous) 的多孔結構；再透過鐵離子置換鈣離子可合成出中孔洞磁性氫氧基磷灰石，施加交流電感應磁場後，材料的溫度約十分鐘後即可上升至熱療所需溫度42°C，並且透過計算出其特定吸收率 (specific absorption rate) 為182 W/g，且於超導性量子干涉儀之分析結果顯示中孔洞磁性氫氧基磷灰石為超順磁性材料，具有良好發熱效率。利用紅外線光譜分析，硬脂酸確實能達到表面改質的目的，使原本親水性的磁性氫氧基磷灰石的表面變為疏水性，藉此可以透過物理吸附上疏水性的抗癌藥物抑特癌，其載藥效率經由UV/Vis檢測為26.12%，相當於每克的材料可以攜帶21.77毫克的抑特癌。 於小鼠纖維母細胞 (3T3 cell) 之WST-1測試結果顯示中孔洞磁性氫氧基磷灰石具有良好的生物相容性，從WST-1測試結果得知，材料通交流電磁場後於熱療溫度42 - 43°C間會降低約40%的A549肺腺癌細胞之存活率；化療部分顯示抑特癌於第一天就有藥物釋放，並於第三天能隨著劑量上升殺死更多的癌細胞；於LDH試驗結果分析，化療合併熱治療無論第一天或第三天都能比單一療法具有更好的療效，具有加成性效果，並於第三天達到殺死約80 %的癌細胞，可達到雙功能(dual function)的療效。

Cancer is the fatal disease in the world. Clinical cancer treatment can be commonly classified into three categories: surgery, radiation therapy and chemotherapy. With research gradually developing, there is an emerging treatment, hyperthermia, which can reduce the side effect of cancer treatment. Hyperthermia can lead cancer cell to death by rising the temperature between 42-47°C in the body tissue. Our topic focuses on the combination of hyperthermia and chemotherapy in order to enhance the efficiency of cancer treatments. As a medicine carrier, magnetic hydroxyapatite (mHAP) shows good biocompatibility. By adding egg white in co-precipitation method to form hydroxyapatite (Ca10(PO4)6(OH)2) and then calcinating it at 800°C to remove carbon, we can develop mesoporous hydroxyapatite. After iron ion (Fe2+) substituting the calcium ion (Ca2+) of hydroxyapatite, we develop mesoporous magnetic hydroxyapatite. It has specific absorption rate at about 182 W/g and it can rise to hyperthermia temperature within ten minutes by adding alternating magnetic field. Besides, it also has superparamagnetic property according to SQUID analysis. Since we use anticancer drug Etoposide is hydrophobic, we use stearic acid to change hydrophilic mesoporous magnetic hydroxyapatite into hydrophobic one. Therefore, we can load Etoposide on mesoporous magnetic hydroxyapatite by adsorption. The loading efficiency is 26.12% by UV/Vis analysis. Mesoporous magnetic hydroxyapatite shows good biocompatibility in 3T3 cell by WST-1 assay. After keeping hyperthermia temperature (42-43°C) for 20 minutes, the cell viability of A549 cells is reduced by 40%. Etoposide release causes cytotoxicity and kills more cancer cells after three days. Evidence shows that combination of hyperthermia and chemotherapy can enhance cancer treatment of hyperthermia or chemotherapy and cause about 80% of cytotoxicity of A549 lung cancer cells after three day treatment. Combination of hyperthermia and chemotherapy can enhance cancer treatment additively and fulfill therapy in dual function.