Role for PPARγ and PPARδ in colonic carcinogenesis

过氧化物酶体增殖物激活受体（PPAR）是一个核受体家族，目前已知PPAR有三种亚型：PPARα、PPARδ和PPARγ。由于最近的报道表明PPAR参与了细胞增殖、分化和细胞死亡的调控，我们研究了PPAR配体在结肠上皮细胞中的作用，得到了以下结果。(1) PPARγ配体抑制结肠癌细胞系细胞生长反应，诱导细胞凋亡。(2) cDNA阵列实验显示，ppar γ诱导的细胞生长抑制与c-myc表达下调、c-jun和gadd153表达上调有关。(3)据报道，hTERT的表达受c-myc调控，而PPARγ配体也下调了hTERT的表达。(4) PPARα和PPARδ配体对结肠癌细胞系细胞生长反应无显著影响。

Peroxisome proliferator-activated receptor (PPAR) is a family of nuclear receptors and three subtypes of PPAR are known at present, PPARα, PPARδ, and PPARγ. Since recent reports suggest the involvement of PPAR in the regulation of cell proliferation, differentiation, and cell death, we studied the effect of PPAR ligands in colonic epithelial cells and obtained the following results. (1) PPARγ ligands suppressed cell growth response in colonic cancer cell lines and induced apoptosis. (2) cDNA array experiments revealed that PPARγ-induced cell growth suppression is associated with the downregulation of c-myc expression and upregulation of c-jun and gadd153 expression. (3) hTERT, of which expression is reported to be regulated by c-myc, was also downregulated by PPARγ ligands. (4) PPARα and PPARδ ligands had no significant effects on cell growth response in colonic cancer cell lines.