第一型血紅素氧化酵素對五胺基酮戊酸光動力治療影響的研究

The Effect of Heme Oxygenase-1 on 5-Aminolevulinic Acid Mediated Photodynamic Therapy

薛宇宏(Yu-Hong Hsueh)

指導教授 ： 陳信銘

國立臺灣大學/醫學院/口腔生物科學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803942

摘要

口腔癌是指口腔內部出現惡性腫瘤的疾病，大多屬於鱗狀細胞癌，由黏膜上鱗狀細胞惡化所致。口腔癌在台灣十大癌症發生率排名第六，死亡率中排名第五。
目前對於口腔癌的治療已經發展出許多方式，不過仍以傳統的手術切除為最快速且有效的方法。但是透過手術切除的治療方式，往往會造成病患的外觀殘存手術痕跡以及疤痕，使得許多病人害怕外觀留下疤痕而錯過黃金治療期。
光動力治療(photodynamic therapy, PDT)是一種治療癌症的新方式，相較起傳統手術切除，光動力治療的範圍侷限在腫瘤組織上而較不影響正常的組織，所以經由光動力治療後病灶的部位不會有明顯的疤痕，對癌症患者來說是一項新的治療選項。但是光動力治療的時間較長，療程通常長達數週至數個月，藥物費用較為昂貴，也容易受到細胞特性的差異而影響到治療效果。因此，如何加強較不敏感的細胞對光動力治療的效果以及縮短治療療程為目前研究光動力治療的一個重要方向。
目前已有三種光敏藥物獲得美國食品與藥品管理局(FDA)的批准，其中最常見的藥物為五胺基酮戊酸(5-aminolevulinic acid, ALA) 。ALA為光感物質:原紫質IX(protoporphyrin IX, PpIX)的前驅物。ALA被癌細胞吸收後，經過一連串的代謝反應形成PpIX，而PpIX會受光激發產生具有細胞毒性的單態氧及自由基(ROS)殺死腫瘤癌細胞。
第一型血紅素氧化酵素(Heme Oxygenase-1, HO-1) 是一種存在細胞質中的酵素，它會將粒線體中的PpIX轉化成血紅素(heme) ，進而降低細胞中PpIX的含量，使得ALA-PDT的治療效果下降。由此可知，癌細胞中的HO-1蛋白表現量會影響光動力治療的成效。本篇研究主要探討不同的口腔癌細胞株其HO-1蛋白表現量如何影響光動力治療，並研究使用抑制劑或天然物質抑制HO-1蛋白的表現後，是否能強化光動力治療的成效。
本篇研究結果顯示，在Ca9-22、OECM1、SAS、HSC3四種口腔癌細胞中，Ca9-22以及OECM1兩株細胞的HO-1表現量較多，SAS及HSC3則較少。而Ca9-22及OECM1細胞在加入ALA後，細胞中累積PpIX量較少，經由ALA-PDT治療後，存活率較高。本篇研究設計將HO-1表現量較高的兩株口腔癌細胞，分別加入不同劑量的Tin protoporphyrin IX(SnPpIX) 、EGCG、Curcumin培養後，p-EGFR、EGFR、 p-PI3K、p-AKT、Nrf2、HO-1蛋白表現量均被抑制。HO-1蛋白表現變少，在加入 ALA之後PpIX累積量上升，原先較不敏感的口腔癌細胞經ALA-PDT後，受光動力照射的癌細胞存活率下降。
由研究結果得知，Ca9-22以及OECM1兩株細胞表現較多的HO-1蛋白。SnPpIX、EGCG、Curcumin皆可透過EGFR、 PI3K、AKT的訊息傳遞路徑調控Nrf2，並進一步抑制HO-1生成，使得癌細胞中PpIX累積量上升，增加ALA-PDT治療的效率。

關鍵字

五胺基酮戊酸光動力 ； 薑黃素 ； 兒茶素 ； 第一型血紅素氧化酵素 ； 口腔癌 ； 原卟啉二氧化錫

並列摘要

Oral cancer is cancer that starts in the mouth or throat and also one of important diseases in Taiwan. Most of oral cancers are squamous cell carcinomas. There are many kinds of approaches to treat oral cancer, the most common way is by surgery. Surgery is the oldest form of treatment for cancer, but surgery will cause irreversible defects on patient’s face. Photodynamic therapy (PDT) now become more and more famous due to the highly safety and effectiveness. However, the PDT costs more money and require a longer time to cure the disease than the traditional surgery. Therefore, how to enhance PDT efficiency and shorten the treatment period of the PDT-non-sensitive cells remain an issue to be resolve.
5-aminolevulinic acid(ALA) is a commonly used drug for PDT. ALA are precursors of protoporphyrin IX(PpIX) and created through a series of metabolic pathways after ALA is absorbed by cancer cells. Heme oxygenase-1 are enzymes located in the cytoplasm, which can convert mitochondrial PpIX into heme. It has been reported that HO-1 protein expression in cancer cells can lower the efficiency of ALA-PDT, because HO-1 reduce cellular PpIX concentration. The aim of this study is to investigate whether potential inhibitor and natural substances could inhibit the expression of HO-1 and enhance the efficacy of ALA-PDT in PDT-non-sensitive cells.
The results showed that different oral cancer cell lines, such as Ca9-22, OECM1, SAS and HSC3 cells had different expressions of HO-1. Ca9-22 and OECM1 expressed higher level of HO-1, which resulted in the lower level of PpIX and the lower sensitivity to ALA-PDT. The HO-1 correlated signal transduction signals, such as p-EGFR, EGFR, p-PI3K, p-AKT, Nrf2 and HO-1, were inhibited by SnPpIX, EGCG and curcumin. When HO-1 expression was inhibited, PpIX would accumulate in cancer cells which can enhance the efficiency of ALA-PDT.
In conclusion, PDT-non-sensitive cells like Ca9-22 and OECM1 express higher level of HO-1 which reduces the accumulation of PpIX in cells. SnPpIX, EGCG and curcumin can inhibit HO-1 expression through EGFR and Nrf2 related signaling pathways, which induce PpIX accumulation and improve the ALA-PDT efficacy.

並列關鍵字

ALA-PDT ； Curcumin ； EGCG ； HO-1 ； Oral Cancer ； SnPpIX

參考文獻

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