Lapillonne Helene, Konopleva Marina, Tsao Twee, Gold David, McQueen Teresa, Sutherland Robert L, Madden Timothy, Andreeff Michael
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.
Cancer Res. 2003 Sep 15;63(18):5926-39.
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.
过氧化物酶体增殖物激活受体γ（PPARγ）是核激素受体超家族的成员，在大量人类癌症中均有表达。在此，我们证明PPARγ在乳腺癌细胞中表达且具有转录活性，与细胞的p53、雌激素受体或人表皮生长因子受体2状态无关。2-氰基-3,12-二氧代齐墩果-1,9-二烯-28-酸（CDDO）是一种新型合成三萜类化合物，是PPARγ的配体。我们研究了CDDO对乳腺癌细胞增殖和凋亡的分子机制。在所有研究的乳腺癌细胞系中，CDDO反式激活PPARγ，诱导剂量和时间依赖性的细胞生长抑制、细胞周期阻滞于G1-S期和G2-M期以及凋亡。然后我们使用差异cDNA阵列分析来研究CDDO诱导的分子变化。将MCF-7和MDA-MB-435细胞暴露于CDDO 16小时后，我们发现两个细胞系中编码以下蛋白质的基因均上调：p21（Waf1/CIP1）；GADD153；CAAT/增强子结合蛋白转录因子家族成员；以及参与泛素-蛋白酶体途径的蛋白质。在下调的基因中，我们重点关注编码细胞周期蛋白D1、增殖细胞核抗原和胰岛素受体底物1的基因。使用蛋白质印迹分析和/或实时PCR，我们证实CDDO调节细胞周期蛋白D1、p21（Waf1/CIP1）和Bcl-2的表达。在基因改造的乳腺癌细胞系中，细胞周期蛋白D1和p21（Waf1/CIP1）还被确认为CDDO生长抑制的重要介质。在免疫缺陷小鼠体内，CDDO能够显著降低MDA-MB-435肿瘤细胞的生长。CDDO可靶向调控细胞周期、凋亡和乳腺癌发生的关键基因，这一发现提示CDDO可作为乳腺癌新型靶向治疗药物。
