Expression of PPAR-γ and its apoptotic significance in lung cancer
HE Xiaoyan, ZHANG Min, CHEN Zhichao, YOU Yong, TIAN Lei, ZOU Ping. Department of Hematology, Xiehe Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R.China
Background and objective Peroxisome proliferator-activated receptor-gamma (PPAR-γ) is a kind of nuclear hormone receptor, which plays important roles in regulating metabolisms. Recently, PPAR-γ was found to express in tumor tissues and cells (including lung cancer), which could be activated by its ligands and affect the differentiation, proliferation and apoptosis of tumor cells. The aim of this study is to investigate the relationship between PPAR-γ expression and clinicopathological characteristics of lung cancer, and to discuss the effect of PPAR-γ activators on lung cancer growth and the mechanisms of apoptosis induction for lung cancer. Methods Expression of PPAR-γ was detected in 15 non-cancerous pulmonary tissues and 64 lung cancer tissues by immunohistochemistry, and the average OD values were investigated by image analysis. Expression of PPAR-γ was detected in lung cancer cell lines by RT-PCR and Western blot. After treated with PPAR-γ activators, apoptosis of cells was detected by TUNEL, and caspase-3 activity was detected by using caspase-3 activity detection kit. Results Expression of PPAR-γ in lung cancer tissues was significantly higher than that in non-cancerous pulmonary tissues. Expression of PPAR-γ was closely related to histological classification, cell differentiation and TNM stages of lung cancer. PPAR-γ could express in two lung cancer cell lines, in which caspase-3 activity was significantly increased and obvious apoptosis was induced after treated with PPAR-γ activators. Conclusion PPAR-γ is closely associated with clinicopathological characteristics of lung cancer. Activated PPAR-γ can increase caspase-3 activity to induce apoptosis of cells. PPAR-γ may be a new target for diagnosis and treatment of lung cancer in the future.