Muñoz-Gámez José Antonio, Rodríguez-Vargas José Manuel, Quiles-Pérez Rosa, Aguilar-Quesada Rocío, Martín-Oliva David, de Murcia Gilbert, Menissier de Murcia Josiane, Almendros Antonio, Ruiz de Almodóvar Mariano, Oliver F Javier
Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd) and Laboratory of Medical Research, Academical Hospital San Cecilio, Granada, Spain.
Autophagy. 2009 Jan;5(1):61-74. doi: 10.4161/auto.5.1.7272. Epub 2009 Jan 27.
Autophagy is a lysosome-dependent degradative pathway frequently activated in tumor cells treated with chemotherapy or radiation. PARP-1 has been implicated in different pathways leading to cell death and its inhibition potentiates chemotherapy-induced cell death. Whether PARP-1 participates in the cell's decision to commit to autophagy following DNA damage is still not known. To address this issue PARP-1 wild-type and deficient cells have been treated with a dose of doxorubicin that induces autophagy. Electron microscopy examination and GFP-LC3 transfection revealed autophagic vesicles and increased expression of genes involved in autophagy (bnip-3, cathepsin b and l and beclin-1) in wild-type cells treated with doxo but not in parp-1(-/-) cells or cells treated with a PARP inhibitor. Mechanistically the lack of autophagic features in PARP-1 deficient/PARP inhibited cells is attributed to prevention of ATP and NAD(+) depletion and to the activation of the key autophagy regulator mTOR. Pharmacological or genetical inhibition of autophagy results in increased cell death, suggesting a protective role of autophagy induced by doxorubicin. These results suggest that autophagy might be cytoprotective during the response to DNA damage and suggest that PARP-1 activation is involved in the cell's decision to undergo autophagy.
自噬是一种依赖溶酶体的降解途径，在接受化疗或放疗的肿瘤细胞中经常被激活。聚（ADP-核糖）聚合酶-1（PARP-1）参与了导致细胞死亡的不同途径，其抑制作用可增强化疗诱导的细胞死亡。PARP-1在DNA损伤后是否参与细胞进入自噬的决定仍不清楚。为了解决这个问题，用诱导自噬的阿霉素剂量处理了PARP-1野生型和缺陷型细胞。电子显微镜检查和绿色荧光蛋白-微管相关蛋白轻链3（GFP-LC3）转染显示，在用阿霉素处理的野生型细胞中存在自噬小泡，且参与自噬的基因（bnip-3、组织蛋白酶b和l以及beclin-1）表达增加，但在PARP-1基因敲除（-/-）细胞或用PARP抑制剂处理的细胞中未出现这种情况。从机制上讲，PARP-1缺陷型/PARP抑制型细胞中缺乏自噬特征归因于ATP和烟酰胺腺嘌呤二核苷酸（NAD(+)）消耗的预防以及关键自噬调节因子哺乳动物雷帕霉素靶蛋白（mTOR）的激活。自噬的药理学或遗传学抑制导致细胞死亡增加，这表明阿霉素诱导的自噬具有保护作用。这些结果表明，在对DNA损伤的反应过程中自噬可能具有细胞保护作用，并表明PARP-1激活参与了细胞进入自噬的决定。
