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）作为光动力治疗（PDT）前列腺癌（CaP）特异性光敏剂。图1描述了这个建议背后的基本概念。我们建议合成一个分子信标（MB），由任何反义寡脱氧核苷酸（AS-ON）序列与靶癌细胞特异性mRNA互补组成。MB含有单链DNA，可以形成茎环结构。循环序列是AS-ON。所述杆通过对位于所述环序列两侧的两个互补臂序列进行退火而形成。染料(D)附着于一臂的末端，猝灭剂(Q)同样附着于另一端。D和Q的接近通过能量转移猝灭了染料的荧光和光反应性。在肿瘤特异性mRNA存在的情况下，MB与mRNA杂交，破坏茎的氢键。淬灭器从达因的附近移除。在光照射下，染料发出荧光并产生细胞毒性单线态氧。信标既可以作为定向光动力治疗（PDT）剂，也可以作为肿瘤特异性诊断剂。我们建议合成含有针对DD3 mRNA的茎环AS-ON序列的BCh1- mbs[图1中D= bacterio叶绿素（BCh1）， Q=类胡萝卜素（Car）]。我们选择DD3作为分子靶标，因为它是迄今为止描述的最特异性的CaP基因之一，并且在CaP中高度过表达。这种基于MB的PDT药物应该是CaP特异性的。我们将重点合成能与DD3 mRNA杂交的BChl-MB，使其荧光和单线态产氧量显著增加。我们将开发细胞特异性肽作为Bchl-MB的递送试剂，并确认该试剂到达目标位点。最后，我们将在两种人类前列腺癌细胞系中验证基于MB的PDT药物的概念。最后，我们将在LNCaP（过表达DD3）和DU145（不表达DD3）两种人类前列腺癌细胞系中验证基于MB的PDT药物的概念。

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).