丹皮酚逆转内质网应激诱导的HepG2细胞凋亡抵抗

目的 探讨丹皮酚逆转内质网应激诱导的HepG2肝癌细胞凋亡抵抗的作用机制.方法 采用MTT及末端双脱氧核苷酸转移酶介导的dUTP缺口标记技术(TUNEL)观察内质网应激诱导剂衣霉素对正常人肝细胞株HL-7702及人肝癌细胞株HepG2细胞的增殖抑制及凋亡作用;Western blot法测定内质网应激诱导剂衣霉素对正常肝细胞HL-7702及肝癌细胞HepG2的环氧合酶-2(COX-2)表达的影响;采用Western blot法及TUNEL法观察COX-2的选择性抑制剂塞来昔布对内质网应激下的肝癌细胞HepG2 COX-2的表达及凋亡的影响;采用MTT及TUNEL法观察丹皮酚对内质网应激下的HepG2肝癌细胞的增殖抑制及凋亡作用;Western blot法观察丹皮酚对内质网应激诱导的HepG2肝癌细胞 COX-2表达的影响:结果与正常肝细胞HL-7702相比,在 TM诱导的内质网应激作用下肝癌细胞HepG2的增殖抑制率及凋亡率减少(P＜0. 05),并且内质网应激可诱导肝癌细胞HepG2产生COX-2蛋白.而丹皮酚可下调内质网应激诱导的HepG2肝癌细胞中COX-2的表达,并使内质网应激诱导的肝癌细胞的凋亡增加.结论 丹皮酚可通过下调COX-2的表达从而逆转内质网应激诱导的HepG2肝癌细胞凋亡抵抗.

Paeonol increases HepG2 cells to endoplasmic reticulum stress-induced apoptosis resistance

Objective To investigate the mechanism of paeonol reversing apoptosis resistance in HepG2 cells induced by endoplasmic reticulum stress. Methods MTT and TUNEL were used to observe the inhibitory effect of endoplasmic reticulum stress inducer-tunicamycin or plus paeonol on human hepatocyte cell line HL-7702 and human hepatocellular carcinoma cell line HepG2. Changes in protein expression of cyclooxygenase-2 (COX-2) and GRP78 (a hallmark of ER stress) in both HepG2 and HL-7702 cells were observed through Western blot. Results Growth inhibition of tunicamycin on HL-7702 was dose dependent. But the growth inhibition of tunicamycin on HepG2 cells reached maximum inhibition in cells. Similar results were observed in TUNEL staining (P ＜0.05). Furthermore, the expression of COX-2 was increased in HepG2 cells but not in HL-7702 cells. Down-regulation of COX-2 expression using the COX-2 inhibitor, celecoxib, increased tunicamycin-induced apoptosis. However, co-treatment with tunicamycin and paeonol significantly increased the rate of apoptosis. Co-treatment with tunicamycin and paeonol also decreased the expression of COX-2. Conclusion Paeonol increases HepG2 cells to ER stress-induced apoptosis by down-regulating COX-2 expression.