Troglitazone Enhances the Apoptotic Response of DLD-1 Colon Cancer Cells to Photodynamic Therapy.
OBJECTIVE
The aim of this study was to investigate whether the peroxisomal proliferator-activated receptor gamma (PPARγ) ligand troglitazone in combination with photodynamic therapy (PDT) enhances the apoptotic response of DLD-1 colon cancer cells.


METHODS
The effects of troglitazone, PDT, and troglitazone in combination with PDT on cell viability and apoptosis were assessed in DLD-1 cells. Cell viability and proliferation were evaluated using the tetrazolium-based MTT assay, and apoptosis was evaluated via cell staining with propidium iodide (PI) and annexin V-FITC. The levels of pro-caspase-3 were measured via Western blot analyses.


RESULTS
Treatment of troglitazone and PDT induced the growth retardation and cell death of DLD-1 cells in a dose-dependent manner, respectively. The combination treatment significantly suppressed cell growth and increased the apoptotic response of DLD-1 and resulted in apoptosis rather than necrosis, as shown by PI/annexin V staining and degradation of procaspase-3.


CONCLUSIONS



CONCLUSIONS
These results document the anti-proliferative and apoptotic activities of PDT in combination with the PPARγ ligand troglitazone and provide a strong rationale for testing the therapeutic potential of combination treatment in colon cancer.
Department of Physiology, Tissue Injury Defense Research Center, Ewha Womans University School of Medicine, Seoul, Korea.
Hyunju
H
Park
Department of Microbiology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Korea.
Si Hwan
SH
Ko
Department of Microbiology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Korea.
Jae Myun
JM
Lee
Department of Microbiology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Korea.
Jeon Han
JH
Park
Department of Physiology, Tissue Injury Defense Research Center, Ewha Womans University School of Medicine, Seoul, Korea. yc@ewha.ac.kr.
Youn Hee
YH
Choi
D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D002839:Chromans / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D047495:PPAR gamma / Q000378:metabolism / Q000494:pharmacology*; D010778:Photochemotherapy; D013778:Tetrazolium Salts; D013844:Thiazoles; D045162:Thiazolidinediones / Q000494:pharmacology* / Q000627:therapeutic use; D000077288:Troglitazone
D000970:Antineoplastic Agents; D002839:Chromans; D047495:PPAR gamma; D013778:Tetrazolium Salts; D013844:Thiazoles; D045162:Thiazolidinediones; D053148:Caspase 3; C022616:thiazolyl blue; D000077288:Troglitazone
PDT; apoptosis; troglitazone