腫瘤標的胜肽之研發及其在化療之應用

Abstract

一 對於住在南中國、台灣及新加坡的人來說，鼻咽癌(Nasopharyngeal carcinoma, NPC)是一種極為常見的癌症。對鼻咽癌病人進行化療常有不小的副作用，然而專一性的標的療法或許可以解決此一問題。利用phage display的方法我們找到一種鼻咽癌細胞的標的胜肽。此一標的胜肽具有與鼻咽癌細胞及鼻咽癌病人檢體專一性結合的能力，同時也可以和在異體移植的鼻咽癌腫瘤細胞有專一性的結合。當與化學治療藥物連結後，其可用於引導化學治療藥物至腫瘤細胞，將腫瘤細胞殺死，而不致因施予化學治療藥物而傷害到其他正常組織及器官。又此一標的胜肽可專一性的與鼻咽癌細胞結合，因此該標的胜肽亦可被應用於作為開發鼻咽癌檢驗試劑用。 二 惡性腫瘤目前不僅在台灣或是全世界已成為一個非常嚴重的公共衛生問題。利用化療方式來治療腫瘤，仍然存在抗藥性及專一性辨認的問題。癌症的標的治療或許可以解決此一問題。我們利用動物活體噬菌體顯現法來尋找針對異體移殖腫瘤血管有專一性結合之胜肽(S5-52 and L4-2)。S5-52 及 L4-2胜肽表現之噬菌體及FITC標記之S5-52 及 L4-2胜肽均可和肺癌細胞株PC13異體移植腫瘤之血管內皮細胞結合，另外在S5-52胜肽表現之噬菌體亦可和喉癌(HEp-2)、口腔癌(SAS)、肺癌(CL1-5)等細胞株之異體移殖腫瘤之血管內皮細胞結合而不與正常組織的血管內皮細胞結合。當此一標記胜肽S5-52與微脂體包裹之化療藥物連結後，可用於引導化療藥物至腫瘤組織，將血管破壞並可殺死腫瘤細胞，而不傷害到其他正常組織及器官。此一標記胜肽S5-52未來極有潛力被應用於作為開發腫瘤之標的治療。

1. Nasopharyngeal carcinoma (NPC) is a common cancer among Chinese living in South China, Taiwan and Singapore. For treatment of NPC by chemotherapy, most cancer chemotherapeutics lack selectivity for cancer cells. Ligand-targeted therapy could afford tumor specificity and limitless toxicity for normal tissue. In this study, we identified a 12-mer peptide (L-peptide) specifically binding to NPC cells by phage display peptide libraries. In vitro, the L-peptide bound to the cell surfaces of most NPC cell lines and biopsy specimens; the L-peptide-linked fluorescence containing liposome was capable of binding to and translocation across plasma membranes. Similarly, the L-peptide-linked liposome that carried doxorubicin (L-peptide-Lipo-Dox) could cause marked NPC cytotoxicity. In vivo, in SCID mice bearing NPC xenograft, the L-phages could specifically bind to the tumor mass; in addition, the L-peptide-Lipo-Dox had higher efficacy to inhibit tumor growth than Lipo-Dox. These results indicate that the L-peptide is a novel peptide, which can specifically bind to NPC cells, and is a good candidate for targeted drug delivery to NPC solid tumors. 2. Malignant tumor has emerged as a major public health problem in developing countries, Taiwan and other parts of world. For treatment of advance tumor by chemotherapy, most cancer chemotherapeutics lack selectivity for cancer cells. Ligand-targeted therapy could afford tumor specificity and limited toxicity for normal tissue. In this study, we identified the 12-mer peptides specifically binding to the neovasculature of SCID mice bearing lung adenocarcinoma xenograft (PC13) by in vivo phage display. We have identified S5-52 and L4-2-phages could bind to the endothelial cells of PC13 xenograft tumors. The FITC-labeled S5-52 peptide and S5-52-phage treated SCID mice also showed the specific binding to neovasculature of xenograft tumors derived from laryngeal cancer (HEp-2), oral cancer (SAS), and lung cancer (CL1-5). The S5-52 peptide could also bind to human umbilical vein endothelial cells (HUVECs). The S5-52 peptide-linked liposome that carried doxorubicin had higher efficacy than Lipo-Dox in inhibit tumor growth without side effect. These results indicate that the S5-52-peptide is a novel peptide, which can specifically bind to neovasculature in xenograft tumors, and is a good candidate for targeted drug delivery to solid tumors.