Mechanisms of Cell Death after Photodynamic Therapy

光动力治疗后细胞死亡的机制

基本信息

批准号：
7665420
负责人：
ANNA-LIISA NIEMINEN
金额：
$ 25.07万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-09-14 至 2011-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7665420
关键词：
Abbreviations Adenine Apoptosis Apoptotic Binding Biochemical Bioenergetics Biological Assay Calpain Cancer Patient Caspase Cathepsins Cell Death Cells Cessation of life Chelating Agents Complex Confocal Microscopy Cultured Cells Cyclosporine Cytosol Data Deferoxamine Methanesulfonate Diamines Endoplasmic Reticulum Esters Ethane Etiology Event Failure Fluorescence Fluorogenic Substrate Fractionation Generations Goals Green Fluorescent Proteins Heterogeneity Inner mitochondrial membrane Inositol Intervention Intracellular Membranes Iron Knock-out Laser Scanning Confocal Microscopy LysoTracker Lysosomes Measurement Measures Mediating Membrane Membrane Potentials Membrane Proteins Mitochondria Mitochondrial Proteins Morphologic artifacts Necrosis Organelles PC4 Gene Pathway interactions Peptide Hydrolases Permeability Photochemotherapy Process Propidium Diiodide Proteins Pump Reactive Oxygen Species Regulation Research Personnel Role Ru 360 Ruthenium Sampling Signal Transduction Singlet Oxygen Starch Superoxide Dismutase Swelling Techniques Therapeutic Effect Time Toxic effect Translations aluminum phthalocyanine cancer cell cell killing cellular imaging chelation crosslink cyclophilin D cytochrome c design dichlorofluorescin enhancing factor inhibitor/antagonist killings mitochondrial dysfunction mitochondrial membrane neoplastic cell phthalocyanine prevent programs promoter red fluorescent protein research study response salicylate spatial relationship tetrakis(4-benzoic acid)porphyrin tetramethylrhodamine tripolyphosphate tumor uptake

项目摘要

DESCRIPTION (provided by applicant): Photodynamic therapy (PDT) with the phthalocyanine photosensitize PC 4 causes rapid generation of reactive oxygen species (ROS), mitochondrial permeability transition (MPT), depolarization and swelling, release of cytochrome c, and activation of both necrosis and caspase-dependent apoptosis in tumor cells. However, PC 4 and a recently synthesized PC 4 derivative PC 181 also localize to endoplasmic reticulum (ER) and lysosomes. We hypothesize that damage to these organelles by PC 4 and PC 181 leads to additional perturbations, such as Ca2+, iron and protease release that ultimately promote MPT-dependent cell killing after PDT. Our goal is to further characterize the role of the MPT in PDT-induced killing of cancer cells and to determine the interactions of damage to ER and lysosomes in promotion of death pathways. In Aim 1, we will characterize changes of cytosolic, mitochondrial and ER Ca2+ after PDT using compartmentally localized fluorescence indicators and Confocal microscopy. Using specific interventions, we will determine whether depletion of ER Ca2+ stores, inhibition of mitochondrial Ca2+ uptake and intramitochondrial chelation act to suppress MPT after PDT and prevent subsequent cell killing. We also determine whether increased cytosolic Ca2+ may activate Ca2+-dependent calpains, to cause Bid processing and translocation to mitochondria with con- sequent mitochondrial dysfunction, MPT, and cell death. In Aim 2, we will investigate the contribution of lysosomal iron and protease release in relation to the MPT and cell death. We will measure cytosolic and mitochondrial chelatable iron using specific fluorescent indicator and determine the effects of compartmentally loaded iron chelators. Similarly, we will assess protease release into the cytosol and investigate the protection conferred by specific cathepsin indicators and knock-out cells. We expect iron and protease release from lysosomes to synergistically promote mitochondrial permeabilization by activating Bid cleavage and translocation to mitochondria. In Aim 3, we will investigate strategies to enhance PDT toxicity in cultured cells and in isolated mitochondria. We will evaluate the ability of salicylate to decrease the threshold of MPT onset and to enhance tumor killing after PDT. The proposed studies will enhance our understanding how to enhance PDT-induced killing of cancer cells and further increase the efficacy of PDT translation to the benefit for cancer patients.

描述（由申请人提供）：使用酞菁光敏剂 PC 4 的光动力疗法 (PDT) 会导致活性氧 (ROS) 的快速产生、线粒体通透性转变 (MPT)、去极化和肿胀、细胞色素 c 的释放以及两种坏死的激活和肿瘤细胞中半胱天冬酶依赖性细胞凋亡。然而，PC 4 和最近合成的 PC 4 衍生物 PC 181 也定位于内质网 (ER) 和溶酶体。我们假设 PC 4 和 PC 181 对这些细胞器的损伤会导致额外的扰动，例如 Ca2+、铁和蛋白酶的释放，最终促进 PDT 后 MPT 依赖性细胞杀伤。我们的目标是进一步表征 MPT 在 PDT 诱导的癌细胞杀伤中的作用，并确定 ER 和溶酶体损伤在促进死亡途径中的相互作用。在目标 1 中，我们将使用区室局部荧光指示器和共聚焦显微镜来表征 PDT 后细胞质、线粒体和 ER Ca2+ 的变化。通过特定的干预措施，我们将确定内质网 Ca2+ 储存的消耗、线粒体 Ca2+ 摄取的抑制和线粒体内螯合是否会在 PDT 后抑制 MPT 并防止随后的细胞死亡。我们还确定增加的胞质 Ca2+ 是否可能激活 Ca2+ 依赖性钙蛋白酶，从而导致 Bid 加工并易位至线粒体，从而导致线粒体功能障碍、MPT 和细胞死亡。在目标 2 中，我们将研究溶酶体铁和蛋白酶释放对 MPT 和细胞死亡的影响。我们将使用特定的荧光指示剂测量细胞质和线粒体的可螯合铁，并确定区室负载的铁螯合剂的效果。同样，我们将评估蛋白酶释放到细胞质中，并研究特定组织蛋白酶指示剂和敲除细胞所赋予的保护作用。我们预计铁和蛋白酶从溶酶体中释放，通过激活 Bid 裂解和易位至线粒体，协同促进线粒体透化。在目标 3 中，我们将研究增强培养细胞和分离线粒体中 PDT 毒性的策略。我们将评估水杨酸盐降低 MPT 起始阈值和增强 PDT 后肿瘤杀伤的能力。拟议的研究将增强我们对如何增强 PDT 诱导的癌细胞杀伤的理解，并进一步提高 PDT 转化的功效，造福癌症患者。