Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
PLoS One. 2013;8(3):e60014. doi: 10.1371/journal.pone.0060014. Epub 2013 Mar 29.
Lymphangioleiomyomatosis (LAM), a multisystem disease of women, is manifest by the proliferation of smooth muscle-like cells in the lung resulting in cystic lung destruction. Women with LAM can also develop renal angiomyolipomas. LAM is caused by mutations in the tuberous sclerosis complex genes (TSC1 or TSC2), resulting in hyperactive mammalian Target of Rapamycin (mTOR) signaling. The mTOR inhibitor, Rapamycin, stabilizes lung function in LAM and decreases the volume of renal angiomyolipomas, but lung function declines and angiomyolipomas regrow when treatment is discontinued, suggesting that factors induced by mTORC1 inhibition may promote the survival of TSC2-deficient cells. Whether microRNA (miRNA, miR) signaling is involved in the response of LAM to mTORC1 inhibition is unknown. We identified Rapamycin-dependent miRNA in LAM patient angiomyolipoma-derived cells using two separate screens. First, we assayed 132 miRNA of known significance to tumor biology. Using a cut-off of >1.5-fold change, 48 microRNA were Rapamycin-induced, while 4 miRs were downregulated. In a second screen encompassing 946 miRNA, 18 miRs were upregulated by Rapamycin, while eight were downregulated. Dysregulation of miRs 29b, 21, 24, 221, 106a and 199a were common to both platforms and were classified as candidate "RapamiRs." Validation by qRT-PCR confirmed that these microRNA were increased. miR-21, a pro-survival miR, was the most significantly increased by mTOR-inhibition (p<0.01). The regulation of miR-21 by Rapamycin is cell type independent. mTOR inhibition promotes the processing of the miR-21 transcript (pri-miR-21) to a premature form (pre-miR-21). In conclusion, our findings demonstrate that Rapamycin upregulates multiple miRs, including pro-survival miRs, in TSC2-deficient patient-derived cells. The induction of miRs may contribute to the response of LAM and TSC patients to Rapamycin therapy.
淋巴管平滑肌瘤病（LAM）是一种女性多系统疾病，其特征是肺内平滑肌样细胞增生，导致囊性肺破坏。患有 LAM 的女性也可能发生肾血管平滑肌脂肪瘤。LAM 是由结节性硬化复合物基因（TSC1 或 TSC2）突变引起的，导致哺乳动物雷帕霉素靶蛋白（mTOR）信号过度活跃。mTOR 抑制剂雷帕霉素可稳定 LAM 的肺功能并减少肾血管平滑肌脂肪瘤的体积，但当治疗停止时，肺功能下降且血管平滑肌脂肪瘤重新生长，这表明 mTORC1 抑制诱导的因素可能促进 TSC2 缺陷细胞的存活。miRNA（miR，miR）信号是否参与 LAM 对 mTORC1 抑制的反应尚不清楚。我们使用两种独立的筛选方法鉴定了 LAM 患者血管平滑肌脂肪瘤衍生细胞中依赖雷帕霉素的 miRNA。首先，我们测定了 132 种已知对肿瘤生物学有重要意义的 miRNA。使用 >1.5 倍变化的截止值，48 个 microRNA 被雷帕霉素诱导，而 4 个 miR 被下调。在第二个包含 946 个 miRNA 的筛选中，18 个 miR 被雷帕霉素上调，而 8 个被下调。miR-29b、21、24、221、106a 和 199a 的失调在两个平台上都是常见的，被归类为候选“RapamiRs”。qRT-PCR 验证证实这些 microRNA 增加。miR-21 是一种促生存的 miR，被 mTOR 抑制（p<0.01）显著上调。miR-21 的调节是细胞类型独立的。mTOR 抑制促进 miR-21 转录物（pri-miR-21）加工成前体形式（pre-miR-21）。总之，我们的研究结果表明，雷帕霉素在 TSC2 缺陷的患者源性细胞中上调多种 miR，包括促生存的 miR。miRs 的诱导可能有助于 LAM 和 TSC 患者对雷帕霉素治疗的反应。
