Novel Strategy for Lung Cancer Treatment using IGFBP-3

使用 IGFBP-3 治疗肺癌的新策略

• 批准号: 7060360
• 负责人: HO-YOUNG LEE
• 金额: $ 24.18万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7060360
• 关键词: antineoplastics; apoptosis; binding proteins; biological signal transduction; clinical research; confocal scanning microscopy; genetically modified animals; human tissue; immunocytochemistry; insulinlike growth factor; laboratory mouse; neoplasm /cancer chemotherapy; neoplasm /cancer pharmacology; neoplasm /cancer therapy; nonsmall cell lung cancer; phosphorylation; protein localization; serine threonine protein kinase; western blottings

DESCRIPTION (provided by applicant): Non-small cell lung cancer (NSCLC) is the major cause of cancer mortality in both women and men with a dismal <15% 5-year survival rate. Clearly, there is an urgent need for novel strategies to treat this disease. One strategy is to use the natural IGF binding protein, IGFBP-3, which regulates the insulin-like growth factor (IGF) pathway that plays a critical role in cell proliferation, antiapoptosis, survival, and neoplastic transformation. This proposal was based on preliminary data which have shown that: A) IGF pathway is selectively activated in NSCLC cells; B) targeting the IGF pathway selectively blocks the growth of NSCLC cells; C) IGFBP-3 has a dual role as a targeted therapeutic strategy for lung cancer treatment because it mediates IGF-independent intracellular antiproliferative and pro-apoptotic effects in addition to its IGF-dependent growth-regulatory function. The two separate pathways of IGFBP-3 may cooperate in an additive or synergistic manner to exert enhanced anti-tumor effects relative to each pathway alone; D) frequent loss of IGFBP-3 expression observed in samples from patients with stage I NSCLC were strongly associated with poor prognosis of stage I NSCLC One potential concern about the use of IGFBP-3 in lung cancer therapy is the presence of an activated protein kinase B (Akt) because we found that Akt induces the phosphorylation of IGFBP-3 leading to its degradation. Akt can be activated in NSCLC cells by IGF as well as by ras mutations and/or overexpression of members of EGFR family and their ligands, such as transforming growth factor alpha (TGF-alpha), which have been observed in 30-80% NSCLC patients. Because Akt can be activated via the Ras pathway even in cells treated with IGFBP-3 that blocks the IGF-mediated Akt activation, we hypothesize that agents, which inhibit IGF-independent Akt activity could enhance the antiproliferative effects of IGFBP-3 in NSCLC cells. Indeed, pharmacologic approach that inhibit Ras activation augmented IGFBP-3 protein level by increasing its stability and enhanced the growth inhibitory effects of IGFBP-3. This suggests that Akt plays a critical role in the function of cellular IGFBP-3 as an IGF-independent growth modulator in NSCLC cells. These and other studies have led to the following hypotheses: 1) IGFBP-3 inhibits lung cancer cell growth by virtue of its ability to bind to IGFs in addition to its IGF-independent effects. 2) Akt may inactivate IGF-independent growth-inhibitory function of IGFBP-3 by decreasing its stability due to phosphorylation in NSCLC cells. 3) Strategies to inhibit Akt activity in addition to suppressing IGF signaling will enhance the therapeutic effects of IGFBP-3 in lung cancer. In this revised RO1 application, I propose to test these hypotheses by exploring the following Specific Aims: 1) To determine whether the incidence and growth of lung tumors are inhibited by an increase in IGFBP-3 level and enhanced by loss of IGFBP-3 through the use of IGF-I transgenic mice and IGFBP-3 null mice. 2) To investigate a) whether inhibition of Akt activity will sensitize NSCLC cells to IGF-independent antiproliferative effects of IGFBP-3, and b) the mechanism through which the activation of Akt leads to NSCLC cell resistance to IGF- independent IGFBP-3 actions. 3) To explore the lung cancer therapeutic activity of a combined gene therapy approach using bicistronic adenoviral vector that inhibits the Akt activity and increases IGFBP-3 expression in IGF-I transgenic mice. We expect that the understanding the mechanism by which IGFBP-3 mediates signals for apoptosis and the mechanism that attenuates the antiproliferative effects of IGFBP-3 in NSCLC cells may lead to the development of more effective approaches to the treatment of lung cancer using IGFBP-3.

描述（由申请人提供）：非小细胞肺癌 (NSCLC) 是女性和男性癌症死亡的主要原因，其 5 年生存率低于 15%。显然，迫切需要新的策略来治疗这种疾病。一种策略是使用天然 IGF 结合蛋白 IGFBP-3，它调节胰岛素样生长因子 (IGF) 通路，在细胞增殖、抗凋亡、存活和肿瘤转化中发挥关键作用。该提议基于初步数据，这些数据表明： A) IGF 通路在 NSCLC 细胞中被选择性激活； B) 靶向IGF通路选择性阻断NSCLC细胞的生长； C) IGFBP-3作为肺癌治疗的靶向治疗策略具有双重作用，因为除了其IGF依赖性生长调节功能之外，它还介导IGF独立的细胞内抗增殖和促凋亡作用。 IGFBP-3的两条独立途径可能以相加或协同的方式合作，相对于单独的每条途径发挥增强的抗肿瘤作用； D) 在 I 期 NSCLC 患者样本中观察到的 IGFBP-3 表达频繁缺失与 I期 NSCLC 的不良预后密切相关，在肺癌治疗中使用 IGFBP-3 的一个潜在担忧是存在激活的蛋白激酶 B (Akt)，因为我们发现 Akt 诱导 IGFBP-3 磷酸化，导致其降解。 Akt 可在 NSCLC 细胞中被 IGF 以及 ras 突变和/或 EGFR 家族成员及其配体（例如转化生长因子 α (TGF-α)）的过度表达激活，这种情况已在 30-80% 的 NSCLC 患者中观察到。因为即使在用 IGFBP-3 处理的细胞中，Akt 也可以通过 Ras 途径激活，从而阻断 IGF 介导的 Akt 激活，因此我们假设抑制 IGF 独立的 Akt 活性的药物可以增强 IGFBP-3 在 NSCLC 细胞中的抗增殖作用。事实上，抑制 Ras 激活的药理学方法通过增加 IGFBP-3 的稳定性来提高 IGFBP-3 蛋白水平，并增强 IGFBP-3 的生长抑制作用。这表明 Akt 在 NSCLC 细胞中作为 IGF 独立生长调节剂的细胞 IGFBP-3 功能中发挥着关键作用。这些研究和其他研究得出了以下假设：1) IGFBP-3 除了具有不依赖于 IGF 的作用外，还凭借其与 IGF 结合的能力来抑制肺癌细胞生长。 2) Akt 可能会因 NSCLC 细胞中的磷酸化而降低 IGFBP-3 的稳定性，从而使 IGFBP-3 的不依赖于 IGF 的生长抑制功能失活。 3) 除了抑制 IGF 信号传导之外，抑制 Akt 活性的策略将增强 IGFBP-3 在肺癌中的治疗效果。在这个修订后的 RO1 申请中，我建议通过探索以下具体目标来测试这些假设：1) 通过使用 IGF-I 转基因小鼠和 IGFBP-3 缺失小鼠，确定 IGFBP-3 水平的增加是否会抑制肺肿瘤的发生和生长，以及 IGFBP-3 的缺失是否会增强肺肿瘤的发生和生长。 2) 研究 a) Akt 活性的抑制是否会使 NSCLC 细胞对 IGFBP-3 的 IGF 独立的抗增殖作用敏感，以及 b) Akt 的激活导致 NSCLC 细胞对 IGF 独立的 IGFBP-3 作用产生抵抗的机制。 3) 探索使用双顺反子腺病毒载体抑制 Akt 活性并增加 IGF-I 转基因小鼠中 IGFBP-3 表达的联合基因治疗方法的肺癌治疗活性。我们期望了解 IGFBP-3 介导细胞凋亡信号的机制以及减弱 IGFBP-3 在 NSCLC 细胞中的抗增殖作用的机制可能会导致开发出更有效的使用 IGFBP-3 治疗肺癌的方法。