Gadd 45 genes sensors of stress and tumor modulators

Gadd 45 应激基因传感器和肿瘤调节剂

• 批准号: 8138188
• 负责人: DAN A LIEBERMANN
• 金额: $ 9.06万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8138188
• 关键词: Apoptosis; Binding; Cell Aging; Cell Cycle Arrest; Cell Cycle Regulation; Cell Death; Cell Nucleus; Cell Survival; Cells; Complement; DNA Repair; Data; Development; Dose; Embryo; Exposure to; Family; Fibroblasts; GADD45; GADD45A gene; GADD45B; GADD45G; Genes; Genotoxic Stress; HRAS gene; In Vitro; Ionizing radiation; JNK-activating protein kinase; Laboratories; M cell; MAP Kinase Gene; MAPK14 gene; MAPK8 gene; Mammalian Cell; Mediating; Molecular; Mouse Strains; Mus; Nature; Oncogenes; Oncogenic; Outcome; Phenotype; Phosphotransferases; Physiological; Play; Predisposition; Proteins; Resistance; Role; Signal Pathway; Signal Transduction; Specificity; Stimulus; Stress; Testing; Tissues; Tumor Promoters; Tumor Suppressor Proteins; biological adaptation to stress; breast tumorigenesis; cancer therapy; carcinogenesis; cell type; in vivo; malignant breast neoplasm; mutant; protein function; research study; response; senescence; sensor; stressor; tool; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Gadd45 genes (a, b, g) are stress sensors that modulate the response of cells to genotoxic/physiological stress, & modulate tumor formation. Gadd45 proteins interact with other stress response proteins, including PCNA, p21, Cdc2/CyclinB1, MEKK4 & p38 kinase. To what extent the functions of Gadd45 proteins overlap, & how the nature of stress stimuli dictate Gadd45 functions to signal cell survival or cell death is unclear. The hypothesis tested is that the nature/magnitude of stress dictates which partners Gadd45 proteins will associate with to signal cell survival or cell death. In response to low stress Gadd45 proteins may interact with p21, cdc2/cyclinB1 & PCNA to activate cell cycle arrest and DNA repair to promote cell survival, whereas in response to high stress, including cellular aging & activated oncogenes, Gadd45 proteins may interact with stress kinases (MEKK4, p38, JNK) to promote apoptosis or senescence. It is surmised that stress sensing functions of Gadd45 proteins play a role in modulating tumor formation. Mice deficient for one or more gadd45 genes & Gadd45 mutant proteins deficient in binding to particular partners were generated to test the hypothesis. Aim 1 will assess the role of Gadd45 & interacting partners in the response of cells to varying doses of genotoxic stress. The effect of Gadd45 deficiencies on cell cycle arrest, survival or apoptosis in gadd45 KO & WT cells in vitro & in vivo, following exposure to low/high levels of genotoxic stress will be tested. Also, the role of Gadd45/partner protein interactions will be explored by testing the ability of transduced wt/mutant gadd45 genes to rescue wt phenotypes. Aim 2 will assess role of Gadd45 & partners in the response of MEFs to physiological/oncogenic stress. Gadd45a-/- & gadd45g-/- MEFs were found to escape replicative & oncogene mediated senescence, whereas gadd45b-/- MEFs lose viability. Gadd45a-/- & gadd45g-/- MEFs were also found to be susceptible to ras transformation, whereas gadd45a/gadd45g double KO MEFs were susceptible for transformation by ras or myc. The role Gadd45 & interacting partners play in senescence, survival & susceptibility to transformation will be explored. Aim 3 will assess function of gadd45 genes as modulators of tumor development. Breast cancer prone MMTV-ras & MMTV-myc mice wt or null for gadd45a were generated. Gadd45a deficiency accelerated MMTV-ras tumor formation, yet retarded MMTV-myc carcinogenesis, indicating that gadd45a functions as tumor promoter/suppressor depending on the oncogene. Experiments are targeted at assessing the role stress response functions of gadd45 genes play in differentially modulating ras/myc driven breast tumorigenesis. Data obtained will be of great importance to better understand the role of stress sensors in tumorigenesis, & how treatment resistance in cancer therapy can arise & be abrogated.

描述（由申请人提供）：Gadd45 基因（a、b、g）是调节细胞对基因毒性/生理应激的反应并调节肿瘤形成的应激传感器。 Gadd45 蛋白与其他应激反应蛋白相互作用，包括 PCNA、p21、Cdc2/CyclinB1、MEKK4 和 p38 激酶。 Gadd45 蛋白的功能在多大程度上重叠，以及应激刺激的性质如何决定 Gadd45 发挥细胞生存或细胞死亡信号的功能尚不清楚。测试的假设是，压力的性质/强度决定了 Gadd45 蛋白将与哪些伙伴结合以发出细胞生存或细胞死亡的信号。在应对低应激时，Gadd45 蛋白可能与 p21、cdc2/cyclinB1 和 PCNA 相互作用，激活细胞周期停滞和 DNA 修复，从而促进细胞存活；而在应对高应激（包括细胞衰老和激活癌基因）时，Gadd45 蛋白可能与应激激酶（MEKK4、p38、JNK）相互作用，促进细胞凋亡或衰老。据推测，Gadd45 蛋白的应激感应功能在调节肿瘤形成中发挥作用。产生一种或多种 gadd45 基因缺陷的小鼠和缺乏与特定伴侣结合的 Gadd45 突变蛋白的小鼠来检验这一假设。目标 1 将评估 Gadd45 及其相互作用伙伴在细胞对不同剂量的基因毒性应激的反应中的作用。将测试暴露于低/高水平的基因毒性应激后，Gadd45 缺陷对体外和体内 gadd45 KO 和 WT 细胞的细胞周期停滞、存活或凋亡的影响。此外，将通过测试转导的 wt/突变体 gadd45 基因拯救 wt 表型的能力来探索 Gadd45/伴侣蛋白相互作用的作用。目标 2 将评估 Gadd45 及其合作伙伴在 MEF 对生理/致癌应激的反应中的作用。发现 Gadd45a-/- 和 gadd45g-/- MEF 可以逃避复制和癌基因介导的衰老，而 gadd45b-/- MEF 则失去活力。还发现 gadd45a-/- 和 gadd45g-/- MEF 对 ras 转化敏感，而 gadd45a/gadd45g 双 KO MEF 对 ras 或 myc 转化敏感。将探讨 Gadd45 和相互作用的伙伴在衰老、生存和转化易感性中发挥的作用。目标 3 将评估 gadd45 基因作为肿瘤发展调节剂的功能。生成了易患乳腺癌的 MMTV-ras 和 MMTV-myc 小鼠，gadd45a 为 wt 或 null。 Gadd45a 缺陷加速了 MMTV-ras 肿瘤的形成，但延缓了 MMTV-myc 的致癌作用，表明 gadd45a 根据癌基因发挥肿瘤启动子/抑制子的作用。实验旨在评估 gadd45 基因的应激反应功能在差异调节 ras/myc 驱动的乳腺肿瘤发生中的作用。获得的数据对于更好地了解压力传感器在肿瘤发生中的作用以及癌症治疗中的治疗耐药性如何产生和消除具有重要意义。