Ligands for peroxisome proliferator-activated receptor gamma inhibit growth of pancreatic cancers both in vitro and in vivo.
Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed largely in adipose tissues and plays an important role in adipocyte differentiation. Several studies have recently shown that ligands of PPARgamma could lead to growth inhibition in some malignancies. In our study, we focused on pancreatic cancers, because the prognosis of advanced pancreatic cancer has not significantly improved due to its resistance to various chemotherapeutic regimens, so that a novel strategy should be required. We show here that PPARgamma is expressed in 5 pancreatic cancer cell lines detected in both mRNA and protein level as well as in human primary and metastatic pancreatic carcinomas examined by immunohistochemical studies. A specific ligand of PPARgamma, troglitazone, led to G1 accumulation with the increase in p27(Kip1), but not p21(Waf1/Cip1) and inhibited cellular proliferation in a pancreatic cancer cell line, Panc-1. The overexpression of PPARgamma in a pancreatic cancer cell line, KMP-3, caused lipid accumulation, which suggested cell growth in some cancers might be inhibited, at least in part, through terminal differentiation in the adipogenic lineage. In addition, implanted Panc-1 tumors in nude mice showed significant inhibition of tumor growth, when treated with pioglitazone, another specific ligand of PPARgamma. Our results suggest that ligands of PPARgamma may be a novel therapeutic agent for the treatment of pancreatic carcinomas.
Itami
A
A
Department of Surgery and Surgical Basic Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Watanabe
G
G
Shimada
Y
Y
Hashimoto
Y
Y
Kawamura
J
J
Kato
M
M
Hosotani
R
R
Imamura
M
M
D017667:Adipocytes / Q000166:cytology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis; D002454:Cell Differentiation; D002455:Cell Division; D002839:Chromans / Q000494:pharmacology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000096:biosynthesis; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000628:therapy*; D010641:Phenotype; D011379:Prognosis; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology; D045162:Thiazolidinediones; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000077288:Troglitazone; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis
D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D002839:Chromans; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D018076:DNA, Complementary; D008024:Ligands; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D013844:Thiazoles; D045162:Thiazolidinediones; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D012313:RNA; D008156:Luciferases; D000077288:Troglitazone