Huang Guohao, Zhang Mengfan, Wang Manzhou, Xu Wenze, Duan Xuhua, Han Xinwei, Ren Jianzhuang
Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 P.R. China.
Oncol Lett. 2024 Feb 19;27(4):160. doi: 10.3892/ol.2024.14294. eCollection 2024 Apr.
Hypoxia is a hallmark of solid tumors. Hypoxic cancer cells adjust their metabolic characteristics to regulate the production of cellular reactive oxygen species (ROS) and facilitate ROS-mediated metastasis. Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that regulates the transcription of fatty acid metabolism-related genes that have a key role in the survival and proliferation function of hypoxic cancer cells. In the present study, mRNA expression in HepG2 cells under chemically induced hypoxia was assessed. The protein expression levels of hypoxia-inducible factor 1α (HIF-1α) were measured using western blotting. Following treatment with the PPARγ agonist pioglitazone, cell viability was assessed using a Cell Counting Kit-8 assay, whilst cell proliferation and death were determined using 5-ethynyl-2'-deoxyuridine incorporation staining, and calcein-acetoxymethyl ester and propidium iodide staining, respectively. Cellular ROS production was assessed using dihydroethidium staining. Cobalt chloride was used to induce hypoxia in HepG2 cells, which was evaluated using HIF-1α expression. The results revealed that the mRNA expression of PPARγ, CD36, acetyl-co-enzyme A dehydrogenase (ACAD) medium chain (ACADM) and ACAD short-chain (ACADS) was downregulated in hypoxic HepG2 cells. The PPARγ agonist pioglitazone decreased the cell viability of hypoxic HepG2 cells by inhibiting cell proliferation and inducing cell death. Following treatment with the PPARγ agonist pioglitazone, hypoxic HepG2 cells produced excessive ROS. ROS-mediated cell death induced by the PPARγ agonist pioglitazone was rescued with the antioxidant N-acetyl-L-cysteine. The downregulated mRNA expression of PPARγ, CD36, ACADM and ACADS was not reverted by a PPARγ agonist in hypoxic HepG2 cells. By contrast, the PPARγ agonist suppressed the mRNA expression of BCL2, which was upregulated in hypoxic HepG2 cells. In summary, the PPARγ agonist stimulated excessive ROS production to inhibit cell proliferation and increase the death of hypoxic HepG2 cells by decreasing BCL2 mRNA expression, suggesting a negative association between PPARγ and BCL2 in the regulation of ROS production in hypoxic HepG2 cells.
缺氧是实体瘤的一个标志。缺氧癌细胞会调整其代谢特征，以调节细胞活性氧（ROS）的产生，并促进ROS介导的转移。过氧化物酶体增殖物激活受体γ（PPARγ）是一种核受体，可调节脂肪酸代谢相关基因的转录，这些基因在缺氧癌细胞的存活和增殖功能中起关键作用。在本研究中，评估了化学诱导缺氧条件下HepG2细胞中的mRNA表达。使用蛋白质印迹法测量缺氧诱导因子1α（HIF-1α）的蛋白质表达水平。用PPARγ激动剂吡格列酮处理后，使用细胞计数试剂盒-8测定法评估细胞活力，同时分别使用5-乙炔基-2'-脱氧尿苷掺入染色、钙黄绿素-乙酰氧基甲酯和碘化丙啶染色来测定细胞增殖和死亡情况。使用二氢乙锭染色评估细胞ROS的产生。使用氯化钴诱导HepG2细胞缺氧，并通过HIF-1α表达进行评估。结果显示，缺氧HepG2细胞中PPARγ、CD36、乙酰辅酶A脱氢酶（ACAD）中链（ACADM）和ACAD短链（ACADS）的mRNA表达下调。PPARγ激动剂吡格列酮通过抑制细胞增殖和诱导细胞死亡，降低了缺氧HepG2细胞的活力。用PPARγ激动剂吡格列酮处理后，缺氧HepG2细胞产生了过量的ROS。抗氧化剂N-乙酰-L-半胱氨酸挽救了PPARγ激动剂吡格列酮诱导的ROS介导的细胞死亡。在缺氧HepG2细胞中，PPARγ激动剂并未使PPARγ、CD36、ACADM和ACADS下调的mRNA表达恢复。相比之下，PPARγ激动剂抑制了缺氧HepG2细胞中上调的BCL2的mRNA表达。总之，PPARγ激动剂通过降低BCL2 mRNA表达，刺激过量ROS产生，从而抑制细胞增殖并增加缺氧HepG2细胞的死亡，这表明在缺氧HepG2细胞的ROS产生调节中，PPARγ与BCL2之间存在负相关。
