title: PpIX induces mitochondria-related apoptosis in murine leukemia L1210 cells.
abstract: BACKGROUND
  Protoporphyrin IX (PpIX), a well-known sensitizer that can enhance laser light or ultrasound induced cytotoxicity in photodynamic and sonodynamic therapy. However, PpIX alone could effectively cause anti-tumor effect and the underlying mechanisms are rarely been reported. Therefore, this study was to investigate the possible mechanism by which PpIX revealed anti-proliferative effect on murine leukemia L1210 cells.
  
  
  METHODS
  The accumulation of PpIX in L1210 cells and normal peripheral blood mononuclear cells (PBMCs) was evaluated with flow cytometry. The subcellular localization of PpIX and apoptosis-inducing factor (AIF) translocation were determined by confocal microscope. The cell viability was examined by MTT assay. Annexin V-PE/7-AAD and DAPI staining were used to detect apoptotic cells. The mitochondrial membrane potential (MMP) changes were tested by rhodamine123 staining. DNA damage was measured by comet assay.
  
  
  RESULTS
  PpIX preferentially accumulated in L1210 cells compared to PBMCs and PpIX mainly located in the mitochondria of L1210 cells. PpIX at a concentration of 1 µg/ml or above exerted significant anti-tumor effect and the cell viability loss presented PpIX dose-dependent manner. Typical apoptotic features such as chromatin condensation were observed by DAPI staining. Annexin V-PE/7-AAD analysis showed 5 µg/ml PpIX could induce about 24% cell apoptosis, which was inhibited by cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition pore. In addition, the PpIX caused MMP loss, AIF translocation to nucleus and serious DNA damage were also suppressed by CsA.
  
  
  CONCLUSIONS
  The results indicate mitochondria-dependent apoptosis were involved in PpIX caused cell damage on L1210 cells.
authors: Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University , Xi'an , China.
authors: Xiaomin
authors: X
authors: Su
authors: Yan
authors: Y
authors: Chen
authors: Xiaobing
authors: X
authors: Wang
authors: Yuan
authors: Y
authors: Wang
authors: Pan
authors: P
authors: Wang
authors: Long
authors: L
authors: Li
authors: Quanhong
authors: Q
authors: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D007939:Leukemia L1210 / Q000188:drug therapy*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects; D000083162:Mitochondrial Permeability Transition Pore; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000494:pharmacology; D011524:Protoporphyrins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D017319:Photosensitizing Agents; D011524:Protoporphyrins; C028025:protoporphyrin IX
keywords: Cytotoxicity; DNA damage; mitochondria damage; murine leukemia l1210 cells; protoporphyrin IX