Activation of peroxisome proliferator-activated receptor gamma by a novel synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid induces growth arrest and apoptosis in breast cancer cells.
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the nuclear hormonal receptor superfamily expressed in a large number of human cancers. Here, we demonstrate that PPARgamma is expressed and transcriptionally active in breast cancer cells independent of their p53, estrogen receptor, or human epidermal growth factor receptor 2 status. 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), a novel synthetic triterpenoid, is a ligand for PPARgamma. We investigated the molecular mechanisms of CDDO on proliferation and apoptosis in breast cancer cells. In all breast cancer cell lines studied, CDDO transactivated PPARgamma, induced dose- and time-dependent cell growth inhibition, cell cycle arrest in G(1)-S and G(2)-M, and apoptosis. We then used differential cDNA array analysis to investigate the molecular changes induced by CDDO. After 16-h exposure of MCF-7 and MDA-MB-435 cells to CDDO, we found genes encoding the following proteins to be up-regulated in both cell lines: p21(Waf1/CIP1); GADD153; CAAT/enhancer binding protein transcription factor family members; and proteins involved in the ubiquitin-proteasome pathway. Among the down-regulated genes, we focused on the genes encoding cyclin D1, proliferating cell nuclear antigen, and the insulin receptor substrate 1. Using Western blot analysis and/or real-time PCR, we confirmed that CDDO regulated the expression of cyclin D1, p21(Waf1/CIP1), and Bcl-2. Cyclin D1 and p21(Waf1/CIP1) were additionally confirmed as important mediators of CDDO growth inhibition in genetically modified breast cancer cell lines. CDDO was able to significantly reduce the growth of MDA-MB-435 tumor cells in immunodeficient mice in vivo. The finding that CDDO can target genes critical for the regulation of cell cycle, apoptosis, and breast carcinogenesis suggests usage of CDDO as novel targeted therapy in breast cancer.
Lapillonne
Helene
H
Department of Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009, USA.
Konopleva
Marina
M
Tsao
Twee
T
Gold
David
D
McQueen
Teresa
T
Sutherland
Robert L
RL
Madden
Timothy
T
Andreeff
Michael
M
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000096:biosynthesis / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D016867:Immunocompromised Host; D051379:Mice; D008819:Mice, Nude; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
C116817:2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid; C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D019938:Cyclin D1; D009828:Oleanolic Acid