以3-胺鄰苯二甲醯胺為光源激發光敏感藥物四苯基噗林之癌症光動力治療研究

Abstract

受限於光穿透深度與強度，光動力治療一般多用於較淺層的癌症如皮膚癌或口腔癌、以及發生於頭頸部之癌症。若要用於治療大腸癌等屬較深層部位之癌症時，通常必須配合內視鏡導入光源至身體內部以引發光敏感藥物之後續光化學反應，而該方式可能造成病患生理或是心理上的不舒適感。此外，由於光無法亦穿透至腫瘤內部，因而當腫瘤的體積太大時治療效果也不彰。 本研究利用化學冷光 3-胺鄰苯二甲醯胺 (luminol) 作為體內光源，激發光敏感藥物四苯基噗林 (meso-tetraphenylporphyrin, TPP) 以進行癌症之光動力治療。我們的目的在於研究 luminol 作為體內光源之可行性，亦希望探討以 luminol作為體內光源激發TPP 後癌症細胞的死亡途徑。 在細胞活性測試中，可以發現在短時間培養下 luminol 對細胞並無明顯毒性，而DMSO 與 TPP 組之吸光值相較於控制組則有略為下降的現象。在較長時間的培養狀況下 luminol、DMSO、TPP 其細胞活性下降之情形較為明顯，而細胞死亡比例較控制組也略為提高。然而，光動力治療組 (PDT) 不論是細胞活性、細胞死亡比例以及細胞染色結果皆與控制、luminol、DMSO、TPP等組有極大的差異，顯示細胞受到嚴重損傷、甚至大量死亡。 細胞死亡途徑方面，PDT 組細胞有縮小的現象、為細胞凋亡 (apoptosis) 的特徵之一，但在染色象限圖中卻無法看到明顯的細胞早期凋亡 (early apoptosis) 現象，我們推測此現象是未抓到正確的觀察時間點所導致。因此，就目前的實驗結果來看尚無法確認細胞的死亡途徑。而從共軛焦顯微鏡的照片可以看出 PDT 組細胞多有染上 PI，顯示細胞的確受到嚴重損傷，然亦可發現染上 Annexin V-FITC 的比例並不高，與流式細胞儀的結果相符。 總而言之，我們認為 luminol 作為體內光源有其可行性，唯需繼續調整實驗參數以獲得更好的治療效果。

Due to the limitation of the penetration depth of light, photodynamic therapy is mainly applied to treat cancers that occur on the surface of the body, such as skin, neck, and oral cavity cancers. If we want to apply photodynamic therapy to treat cancers in the inner body, such as colon cancer, we would have to deliver the light in some special ways, for example, by using optical fibers along with endoscopes to deliver the light to the inner body. However, colonoscopy might be uncomfortable for most patients mentally and physically. Also, light cannot penetrate into the tumor with large volume, which reduces the effectiveness of treatment. In order to expand the application of photodynamic therapy in the inner body, we used luminol as the light source to activate the porphyrin family photosensitizer, meso-tetraphenylporphyrin (TPP), to achieve photodynamic therapy. From experiment, we could know that luminol and FeSO4 did not cause damages to cells on day 1, and cells incubated with DMSO or TPP showed slightly decrease in cell viability. On day 3, we found that the effects of luminol, DMSO, and TPP on cells were more obvious than day 1 and there were also slight increases in cytotoxicity in comparison with the control group. Among those experimental groups, PDT treated group had the lowest cell viability and highest cytotoxicity on both day 1 and day 3, which showed that cells were seriously damaged and further died in large amounts. We had the similar results from the flow cytometry and confocal microscope outcome. In the analysis of cell death pathway, we found that cell had shrunk after PDT treatment, which is a feature of apoptosis. However, we could not observe early apoptosis signals from the Annexin V-FITC/PI staining results. We thought that the incorrect timing to capture early apoptosis signals may be the cause of this phenomenon. Therefore, we could not make a clear conclusion from the data. In brief, we thought that luminol is a promising light source in the inner body, and we would continue to adjust the experimental parameters for better treatment results.