Photodynamic Therapy for Prostate Cancer

本项目的总体目标是开发基于细菌叶绿素-类胡萝卜素的分子信标（BChl-MB）作为用于光动力疗法（PDT）的前列腺癌（CaP）特异性光敏剂。图1描述了这一提议的基本概念。我们建议合成一个分子信标（MB）组成的任何反义寡脱氧核苷酸（AS-ON）序列互补的mRNA特异性的靶癌细胞。MB含有可形成茎环结构的单链DNA。环序列是一个AS-ON。茎是由位于环序列两侧的两个互补臂序列退火形成的。染料（D）连接到一个臂的末端，猝灭剂（Q）类似地连接到另一个末端。D和Q的接近通过能量转移猝灭染料的荧光和光反应性。在存在肿瘤特异性mRNA的情况下，MB与mRNA杂交，破坏茎的氢键。将猝灭剂从达因的紧邻处移除。在用光照射时，染料发射荧光并产生细胞毒性单线态氧。该信标既作为定向光动力治疗（PDT）剂又作为肿瘤特异性诊断剂。我们提出合成BCh 1-Mbs [在图1中D=细菌叶绿素（BCh 1），Q=类胡萝卜素（Car）]，其含有靶向DD 3 mRNA的茎环AS-ON序列。我们选择DD 3作为分子靶标，因为它是迄今为止描述的最具CaP特异性的基因之一，并且在CaP中高度过表达。这种基于MB的PDT试剂应该是CaP特异性的。我们将集中在合成的BChl-MB，可以与DD 3 mRNA杂交，导致荧光和单线态氧产量的显着增加。我们将开发细胞特异性肽作为Bchl-MB的递送试剂，并确认该试剂到达靶位点。最后，我们将在两个人前列腺癌细胞系中验证基于MB的PDT试剂的概念。最后，我们将在两种人前列腺癌细胞系LNCaP（过表达DD 3）和DU 145（不表达DD 3）中验证基于MB的PDT剂的概念。

The overall objective of this project is to develop bacteriochlorophyll- carotenoid based molecular beacons (BChl-MB) as prostate cancer (CaP)-specific photosensitizers for photodynamic therapy (PDT). The basic concept underlying this proposal is depicted in Figure 1. We propose to synthesize a molecular beacon (MB) consisting of any antisense oligodeoxynucleotide (AS-ON) sequence complementary to an mRNA specific for the target cancer cells. The MB contains a single- stranded DNA that can form a stem-loop structure. The loop sequence is an AS-ON. The stem is formed by the annealing of two complementary arm sequences that are on either side of the loop sequence. A dye (D) is attached to the end of one arm and a quencher (Q) is similarly attached to the other end. Proximity of D and Q quenches fluorescence and photoreactivity of the dye by energy transfer. In the presence of the tumor specific mRNA, the MB hybridizes with the mRNA, disrupting the hydrogen bonds of the stem. The quencher is removed from the immediate vicinity of the dyne. Upon irradiating with light, the dye emits fluorescence and generates cytotoxic singlet oxygen. The beacon serves both as a directed photodynamic therapy (PDT) agent and as a tumor specific diagnostic agent. We are proposing to synthesize BCh1-Mbs [in Fig. 1 D= bacteriochlorophyll (BCh1), Q= carotenoid (Car)] containing stem-loop AS-ON sequence targeted at the DD3 mRNA.. We have selected DD3 as the molecular target because it is one of the most CaP- specific genes described to date and is highly over-expressed in CaP. Such MB based PDT agents should be CaP-specific. We will focus on the synthesis of the BChl-MB that can hybridize with DD3 mRNA resulting in the significant increase of the fluorescence and the singlet oxygen production. We will develop cell-specific peptides as delivery reagents fort Bchl-MB and confirm that this agent reaches the target sites. Finally, we will validate the concept of MB based PDT agents in two human prostate cancer cell lines. Finally, we will validate the concept of MB based PDT agents in tow human prostate cancer cell lines, LNCaP (over-expressing DD3) and DU145 (not expressing DD3).