The Role of Caspase 9b Expression in NSCLC Survival/Chemotherapeutic Sensitivity

Caspase 9b 表达在 NSCLC 生存/化疗敏感性中的作用

• 批准号: 8764706
• 负责人: CHARLES E. CHALFANT
• 金额: --
• 依托单位: VA VETERANS ADMINISTRATION HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8764706
• 关键词: AKT Signaling Pathway; Accounting; Alternative Splicing; Anchorage-Independent Growth; Apoptosis; Apoptotic; Applications Grants; Biological; Cancer Model; Caspase; Cause of Death; Cell Proliferation; Cells; Ceramide Signaling Pathway; Ceramides; Cessation of life; Cisplatin; Clinic; Data; Developed Countries; Development; Disease; Distal; Effectiveness; Elements; Enzymes; Epidermal Growth Factor Receptor; Epithelial Cells; Event; Exclusion; Exons; Family; Family member; Generations; Goals; Growth; Health; Heterogeneous-Nuclear Ribonucleoprotein L; Human; In Vitro; Laboratories; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Mediator of activation protein; Messenger RNA; Mutation; Non-Small-Cell Lung Carcinoma; Oncogenic; PI3K/AKT; Paclitaxel; Pathway interactions; Patients; Phenotype; Phosphorylation; Physiological; Play; Production; Protein Isoforms; Protein Phosphatase 2A Regulatory Subunit PR53; Proto-Oncogene Proteins c-akt; RNA; RNA Splicing; Radiation; Reporting; Repression; Research; Resistance; Role; Signal Pathway; Signal Transduction; Sphingolipids; Testing; Time; Transcript; Tumor Suppression; United States; Unresectable; Veterans; Woman; Work; anti-cancer therapeutic; base; cancer cell; caspase-9; cell transformation; ceramide-activated protein phosphatase; chemotherapeutic agent; chemotherapy; clinically relevant; combat; dihydroceramide desaturase; in vivo; mRNA Precursor; men; metaplastic cell transformation; mortality; mouse model; novel; novel therapeutics; outcome forecast; palliative; pre-clinical; preclinical study; protein complex; senescence; tumor; tumorigenic

DESCRIPTION (provided by applicant): Today, lung cancer is the leading cause of death in both men and women in industrialized countries, accounting for an estimated 28% of all cancer deaths in the United States. Non-small cell lung cancers (NSCLC) represent the majority of lung cancers and carry a poor prognosis with a median survival of less than 12 months. Most patients present with unresectable disease and current treatment options of chemotherapy and radiation are palliative at best. Therefore, new strategies are needed in the treatment of NSCLC in order to impact this disease. In this study, we are focusing on NSCLC models for examining distal signaling mechanisms that modulate the chemotherapy sensitivity, generation, and maintenance of NSCLC cells/tumors. Specifically, this grant application focuses on the survival/oncogenic signaling pathways activated by caspase 9b. The expression of caspase 9b is regulated by alternative splicing via the inclusion or exclusion of a four exon cassette (exons 3, 4, 5, and 6). Inclusion of this exon cassette into the mature transcript produces the pro- apoptotic caspase 9 (caspase 9a) while the exclusion produces the anti-apoptotic and survival signaling factor, caspase 9b. Studies from our laboratory have demonstrated that NSCLC tumors present with a dysregulated (e.g. low) ratio of caspase 9/caspase 9b analogous to an anti-apoptotic/chemotherapy resistance phenotype. Subsequent studies by our laboratory demonstrated that the alternative splicing of caspase 9 had important functions in the anchorage-independent growth (AIG) of NSCLC cells, AIG induced by oncogenic mutation in non-transformed human bronchial epithelial cells, and chemotherapy sensitivity (e.g. cisplatinum and paclitaxel). Mechanistically, our laboratory identified an exonic splicing silencer (C9/E3-ESS) in exon 3 that regulates the inclusion of the exon 3, 4, 5, and 6 cassette of caspase 9 pre-mRNA. hnRNP L was shown to associate with this RNA cis-element, repress the inclusion of the exon cassette, and induce caspase 9b expression. Importantly, phosphorylation of hnRNP L on ser52 (observed only in transformed cells) was required for repression of the exon 3,4,5,6 cassette. Lastly, ser52 phosphorylation of hnRNP L was shown as a required mediator of the tumorigenic capacity of NSCLC cells via the alternative splicing of caspase 9. These key mechanisms are specific to transformed cells, translatable to >70% of NSCLCs, and at an extreme distal point in oncogenic pathways. Therefore, these distal mechanisms are plausible and highly desired targets for the development of new anti-cancer therapeutics. The proposed studies will determine the mechanisms and cell signaling pathways regulated by the survival product of caspase 9 RNA splicing, caspase 9b. These studies will also examine naturally occurring tumor suppression pathways (e.g. sphingolipid pathways) that block the production of caspase 9b, and thereby inhibit the growth of NSCLC tumors. Furthermore, we are proposing pre-clinical studies to determine whether the specific targeting of caspase 9b is effective for treating NSCLC by enhancing the effectiveness of current chemotherapeutic agents used in the clinic (e.g. cisplatinum and paclitaxel).

描述（由申请人提供）： 如今，肺癌已成为工业化国家男性和女性死亡的主要原因，估计占美国所有癌症死亡的28％。非小细胞肺癌（NSCLC）代表大多数肺癌，并且预后较差，中位存活率少于12个月。大多数患者出现了不可切除的疾病和当前的化学疗法和放射治疗选择，充其量是姑息性的。因此，为了影响这种疾病，需要采取新的策略来治疗NSCLC。在这项研究中，我们关注的是NSCLC模型，用于检查远端信号传导机制，以调节NSCLC细胞/肿瘤的化学疗法敏感性，生成和维持。具体而言，该赠款的应用集中在caspase 9b激活的生存/致癌信号通路上。 caspase 9b的表达通过包含或排除四个外显子盒（外显子3、4、5和6）的替代剪接来调节。将这种外显子盒纳入成熟的转录本中会产生凋亡的caspase 9（caspase 9a），而排除产生抗凋亡和存活信号传导因子caspase 9b。我们实验室的研究表明，NSCLC肿瘤的caspase 9/caspase 9B表现出与抗凋亡/抗凋亡/化学疗法耐药性表型相似的（例如低）比率。 我们实验室的随后研究表明，caspase 9的替代剪接在非转化的人支气管上皮细胞中致癌突变引起的NSCLC细胞的锚固非依赖性生长（AIG）中具有重要功能，以及化学疗法的敏感性（例如，化学疗法）。 从机械上讲，我们的实验室确定了外显子3中的外显微剪接消音器（C9/E3-ESS）调节外显子3、4、5和6 caspase 9的盒式盒子9前MRNA。 HNRNP L显示与此RNA顺式元素相关，抑制外显子盒的包含，并诱导caspase 9b表达。重要的是，Ser52上HNRNP L的磷酸化（仅在转化的细胞中观察到）才能抑制外显子3,4,5,6盒式盒。最后，HNRNP L的SER52磷酸化显示为NSCLC细胞通过caspase 9的替代拼接的替代介质的介体。这些关键机制特定于转化的细胞，可翻译成> 70％的NSCLC，以及在基因生成途径的极端远端点。因此，这些远端机制对于开发新的抗癌治疗剂是合理且高度期望的靶标。拟议的研究将确定由caspase 9 RNA剪接（caspase 9b的生存产物）调节的机制和细胞信号通路。这些研究还将检查自然存在的肿瘤抑制途径（例如鞘脂途径），以阻断caspase 9b的产生，从而抑制NSCLC肿瘤的生长。此外，我们正在提出临床前研究，以确定caspase 9b的特异性靶向是否通过增强临床中使用的当前化学治疗剂的有效性来有效治疗NSCLC（例如顺铂和紫杉醇）。