Department of Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Oncol Rep. 2010 Jun;23(6):1537-43. doi: 10.3892/or_00000793.
Notch and Hedgehog activate cell-cycle progression of adult and cancer stem cells. Notch is activated by DLL and Jag presents on neighboring cells. We investigated the effects of density of the Notch-activating ligand, Jag-1, and targeting Gli-1, in activation of division of paclitaxel/taxol-resistant, (PTX Res) ovarian cancer cells SKOV3 (SKOV3). We used the specific gamma-presenilin inhibitor, DAPT, to identify the specificity of activating signals for Notch-1 and created 'butterfly-duplex-3548-Gli-1-inhibitory RNA' (i-Gli-1.RNA) to inhibit cell division. To accurately quantify kinetics of division, the expression of CD44 and CD24 was determined in each gated population of divided cells. CD44 High proliferated when activated by Jag-1 Low and poorly when activated by Jag-1 High. DAPT inhibited proliferation of cells activated by Jag-1 Low, and increased proliferation of cells activated by Jag-1 High. Only 5-10% of cells activated by Jag-1 High and Jag-1 Low divided fast, polynomial, and symmetric. i-Gli-1.RNA eliminated more than 50% of the small CD44 High/CD24 Neg cells in divisions 3 and 4. This effect appeared specific compared with cells transfected with negative control siRNA. i-Gli-1.RNA had no effect on large CD44 High/CD24 Neg cells, but inhibited the population of CD44 High/CD24 Low cells. Expansion of CD44 High inversely correlated with Jag-1 density on activating autologous tumor and fibrosarcoma cells. Created i-RNAs may decrease the resting CSC pool. Notch and Gli-1 signals play an important role in proliferation/division and survival of cancer stem cells. Targeting Notch-1 through its enhancer Gl-1, should be significant for novel treatments to eliminate taxol-resistant cancer stem cells (CSC). i.Gli-1 RNA should be more effective if used together with Taxol.
Notch 和 Hedgehog 激活成年和癌症干细胞的细胞周期进程。Notch 通过 DLL 和 Jag 在相邻细胞上被激活。我们研究了 Notch 激活配体 Jag-1 的密度以及针对 Gli-1 的靶向作用对紫杉醇/紫杉醇耐药（PTX Res）卵巢癌细胞 SKOV3（SKOV3）分裂的影响。我们使用了特异性的γ-早老素抑制剂 DAPT，以确定 Notch-1 的激活信号的特异性，并创建了“蝶形双链 3548-Gli-1 抑制性 RNA”（i-Gli-1.RNA）来抑制细胞分裂。为了准确地量化分裂的动力学，在每个分裂细胞的门控群体中确定了 CD44 和 CD24 的表达。当 Jag-1 Low 激活时，CD44 High 增殖，而当 Jag-1 High 激活时增殖不佳。DAPT 抑制 Jag-1 Low 激活的细胞增殖，并增加 Jag-1 High 激活的细胞增殖。只有 5-10%的由 Jag-1 High 和 Jag-1 Low 激活的细胞快速、多项式和对称分裂。i-Gli-1.RNA 在第 3 和第 4 次分裂中消除了超过 50%的小 CD44 High/CD24 Neg 细胞。与转染阴性对照 siRNA 的细胞相比，这种效果似乎是特异性的。i-Gli-1.RNA 对大 CD44 High/CD24 Neg 细胞没有影响，但抑制了 CD44 High/CD24 Low 细胞群体。CD44 High 的扩增与激活自体肿瘤和纤维肉瘤细胞上的 Jag-1 密度呈反比。创建的 i-RNAs 可能会减少静止的 CSC 池。Notch 和 Gli-1 信号在癌症干细胞的增殖/分裂和存活中发挥重要作用。通过其增强子 Gl-1 靶向 Notch-1 应该对消除紫杉醇耐药癌症干细胞（CSC）的新型治疗方法具有重要意义。如果与 Taxol 一起使用，i.Gli-1 RNA 应该更有效。
