Sun Yang, Gallacchi Dana, Zhang Erik Y, Reynolds Samuel B, Robinson Lauren, Malinowska Izabela A, Chiou Terry T, Pereira Ana M, Li Chenggang, Kwiatkowski David J, Lee Po-Shun, Yu Jane J
Brigham and Women's Hospital/Harvard Medical School, Boston, Massachusetts.
Am J Respir Cell Mol Biol. 2014 Dec;51(6):738-49. doi: 10.1165/rcmb.2014-0033OC.
Lymphangioleiomyomatosis (LAM) is a female-predominant cystic lung disease that can lead to respiratory failure. LAM cells typically have inactivating tuberous sclerosis complex 2 (TSC2) mutations and mammalian target of rapamycin (mTOR) complex (mTORC) 1 activation. Clinical response to the mTORC1 inhibitors has been limited, prompting a search for additional therapy for LAM. In this study, we investigated the impact of TSC2 on the expression of poly (ADP-ribose) polymerase (PARP)-1 that initiates the DNA repair pathway, and tested the efficacy of PARP1 inhibitors in the survival of TSC2-deficient (TSC2(-)) cells. We analyzed publicly available expression arrays of TSC2(-) cells and validated the findings using real-time RT-PCR, immunoblotting, and immunohistochemistry. We examined the impact of rapamycin and Torin 1 on PARP1 expression. We also tested the effect of PARP1 inhibitors, 8-hydroxy-2-methylquinazoline-4-one and 3,4-dihydro-5[4-(1-piperindinyl)butoxy]-1(2H)-isoquinoline, on the survival of TSC2(-) cells. We identified the up-regulation of PARP1 in TSC2(-) cells relative to cells in which wild-type TSC2 has been reintroduced (TSC2-addback [TSC2(+)] cells). The transcript levels of PARP1 in TSC2(-) cells were not affected by rapamycin. PARP1 levels were increased in TSC2(-) cells, xenograft tumors of rat-derived TSC2(-) cells, renal cystadenomas from Tsc2(+/-) mice, and human LAM nodules. RNA interference of mTOR failed to reduce PARP1 levels. Proliferation and survival of TSC2(-) cells was reduced in response to PARP1 inhibitor treatment, more so than TSC2(+) cells. TSC2(-) cells exhibit higher levels of PARP1 relative to TSC2(+) cells in an mTOR-insensitive manner. PARP1 inhibitors selectively suppress the growth and induce apoptosis of TSC2(-) cells from patients with LAM. Targeting PARP1 may be beneficial in the treatment of LAM and other neoplasm with mTORC1 activation.
淋巴管平滑肌瘤病(LAM)是一种以女性为主的囊性肺部疾病,可导致呼吸衰竭。LAM细胞通常具有结节性硬化复合物2(TSC2)失活突变和雷帕霉素哺乳动物靶标(mTOR)复合物(mTORC)1激活。对mTORC1抑制剂的临床反应有限,这促使人们寻找LAM的其他治疗方法。在本研究中,我们研究了TSC2对启动DNA修复途径的聚(ADP-核糖)聚合酶(PARP)-1表达的影响,并测试了PARP1抑制剂对TSC2缺陷(TSC2(-))细胞存活的疗效。我们分析了公开可用的TSC2(-)细胞表达阵列,并使用实时RT-PCR、免疫印迹和免疫组织化学验证了结果。我们研究了雷帕霉素和Torin 1对PARP1表达的影响。我们还测试了PARP1抑制剂8-羟基-2-甲基喹唑啉-4-酮和3,4-二氢-5[4-(1-哌啶基)丁氧基]-1(2H)-异喹啉对TSC2(-)细胞存活的影响。我们发现相对于重新引入野生型TSC2的细胞(TSC2回补[TSC2(+)]细胞),TSC2(-)细胞中PARP1上调。TSC2(-)细胞中PARP1的转录水平不受雷帕霉素影响。PARP1水平在TSC2(-)细胞、大鼠来源的TSC2(-)细胞的异种移植肿瘤、Tsc2(+/-)小鼠的肾囊肿腺瘤和人LAM结节中升高。mTOR的RNA干扰未能降低PARP1水平。与TSC2(+)细胞相比,PARP1抑制剂处理后TSC2(-)细胞的增殖和存活减少得更多。相对于TSC2(+)细胞,TSC2(-)细胞以mTOR不敏感的方式表现出更高水平的PARP1。PARP1抑制剂选择性抑制LAM患者TSC2(-)细胞生长并诱导其凋亡。靶向PARP1可能对LAM和其他具有mTORC1激活的肿瘤的治疗有益。