Pten/AKT and Siah in Regulation of Hypoxia

Pten/AKT 和 Siah 在缺氧调节中的作用

• 批准号: 7713761
• 负责人: Ze'ev A Ronai
• 金额: $ 44.14万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7713761
• 关键词: 2-oxoglutarate 3-dioxygenase proline; Adaptor Signaling Protein; Address; Affect; Attenuated; Biochemistry; Biology; Cellular biology; Collaborations; Data; Development; Disease Outcome; Fingers; Foundations; Genes; Genetic; Genetic Transcription; Hypoxia; Hypoxia Inducible Factor; In Vitro; Laboratories; Link; Mammary gland; Maps; Mediating; Melanoma Cell; Metabolic Pathway; Metastatic Melanoma; Modeling; Molecular Biology; Mus; Neoplasm Metastasis; Pancreas; Pathway interactions; Play; Post-Translational Protein Processing; Process; Prostatic Neoplasms; Proteins; Proto-Oncogene Proteins c-akt; Ras Signaling Pathway; Ras/Raf; Regulation; Regulatory Pathway; Reporting; Role; Scaffolding Protein; Signal Pathway; Signal Transduction; Staging; TSC1/2 gene; Testing; Tumorigenicity; Work; base; in vivo; inhibitor/antagonist; melanocyte; melanoma; mouse model; pancreatic neoplasm; promoter; selective expression; tumor; tumorigenesis; ubiquitin ligase

Understanding mechanisms underlying control of tumorigenesis and metastasis is central to development of means to intervene in these processes. Reports from three laboratories suggest that the Siah ubiquitin ligases (Siahl and Siah2) function in pancreatic, mammary, melanoma and prostate tumor development and/or progression. Our studies revealed the role of Siah2 in melanoma development and progression through its effect on HIF and Ras signaling pathways. By regulating prolyl hydroxylase 3 stability, Siah2 controls HIFIa availability and the ability of melanoma cells to metastasize, without affecting tumorigenicity. By regulating Sprouty2 (SPRY2) stability, Siah2 regulates Ras and Raf signaling pathways, which dictate melanoma tumorigenicity. Consistent with these findings, Siah2 expression increases in more mestastatic melanomas, as determined by analysis of melanoma TMA. These findings provide a rationale to investigate mechanisms underlying regulation and function of Siah2 in melanoma. Our initial observations also suggest that AKT regulates Siah2 transcription. We will delineate mechanisms underlying Akt-mediated increase of Siah2 expression in melanoma where 50% of tumors contain a constitutively active Akt. Collectively, our findings indicate that: (i) Siah2 expression is upregulated in malignant melanomas, (ii) Siah2 inhibition attenuates melanoma tumorigenicity through SPRY2-Ras signaling, (iii) Siah2 inhibition attenuates melanoma metastasis through PHD3-HIF signaling, and (iv) AKT regulates Siah2 expression. Together, these observations provide the foundation for our hypothesis that under the control of AKT signaling, Siahl/2 plays a central role In regulation of melanoma tumorigenesis and metastasis. To test this hypothesis we will use biochemistry, molecular biology, cell biology and mouse models to: (1) extend our original findings defining AKT-dependent mechanisms underlying regulation of Siah2 transcription, and (2) characterize Siah2-Sprouty2 interaction relevant to different stages of melanoma tumor development. We will also (3) utilize Tg-N-Ras/Alnk4a mice, which develop metastatic melanoma, to assess the role of Siah (following crosses with Siah1a'':Siah2"''and Siah2"'":Siah1a*'' mice) in melanoma development and progression. Additional studies addressing Siah2 activity in tumorigenesis and metastasis will be carried out in collaboration with Project 2 to identify metabolic pathways affected by Siah2 and with Project 3, which focuses on identification and characterization of Siah2 inhibitors. Collectively this project should provide new important information regarding the role of Siah2 in regulating melanoma tumorigenesis and metastasis.

了解肿瘤发生和转移的潜在控制机制是 发展干预这些进程的手段。三个实验室的报告显示， Siah泛素连接酶（Siah 1和Siah 2）在胰腺、乳腺、黑素瘤和前列腺中起作用 肿瘤发展和/或进展。我们的研究揭示了Siah 2在黑色素瘤中的作用， 其通过对HIF和Ras信号通路的作用而发生和发展。通过调节 脯氨酰羟化酶3的稳定性，Siah 2控制HIFIa的可用性和黑色素瘤细胞的能力， 转移，而不影响致瘤性。通过调节Sprouty 2（SPRY 2）的稳定性，Siah 2调节 Ras和Raf信号通路，决定黑色素瘤致瘤性。符合这些 研究发现，Siah 2表达在更多的转移性黑色素瘤中增加，这是通过分析 黑素瘤TMA。 这些发现提供了一个理论基础，以调查机制的调控和功能， 黑色素瘤中的Siah 2。我们的初步观察还表明，AKT调节Siah 2转录。我们 将描述黑色素瘤中Akt介导的Siah 2表达增加的潜在机制， 50%的肿瘤含有组成型活性Akt。 总的来说，我们的研究结果表明：（i）Siah 2表达在恶性黑色素瘤中上调，（ii） Siah 2抑制通过SPRY 2-Ras信号传导减弱黑素瘤致瘤性。 通过PHD 3-HIF信号传导减弱黑素瘤转移，和（iv）AKT调节Siah 2 表情总之，这些观察结果为我们的假设提供了基础，即在 Siahl/2控制AKT信号传导，在调节黑色素瘤肿瘤发生中起核心作用， 转移为了验证这一假设，我们将使用生物化学，分子生物学，细胞生物学和小鼠 模型：（1）扩展我们最初的发现，定义AKT依赖性机制的调节 的Siah 2转录，和（2）表征Siah 2-Sprouty 2相互作用相关的不同阶段， 黑色素瘤肿瘤发展。我们还将（3）利用Tg-N-Ras/Alnk 4a小鼠，其发展转移性肿瘤， 黑色素瘤，以评估Siah的作用（与Siah 1a“：Siah 2”和Siah 2“：Siah 1a”杂交后） 小鼠）在黑色素瘤发展和进展中的作用。关于Siah 2活性的其他研究 肿瘤发生和转移将与项目2合作进行，以确定代谢 受Siah 2影响的途径和项目3，其重点是识别和表征 Siah 2抑制剂。总的来说，这个项目应该提供新的重要信息， siah 2在黑色素瘤发生和转移中的调控作用。