Project 1 - Siah 1 in ER and Mitochondrial Function and Homeostasis in Melanoma

总结-项目1：ER中的SIAH 1和线粒体功能和稳态 黑素瘤 越来越多的证据表明，适应性未折叠蛋白反应（UPR）的激活发生在 黑色素瘤细胞后药物治疗。UPR感知氧化应激、线粒体功能障碍和 动态和解决ER中的蛋白质错误折叠，在黑色素瘤肿瘤细胞中经常失调的活动。 值得注意的是，UPR信号传导的程度在黑色素瘤亚型之间不同，这与肿瘤的发生和发展是一致的。 异质性和可塑性，并且是适应化疗和相关应激刺激的倾向的基础。 最近，肿瘤抗性与主基因的表达和活性改变有关。 调节剂PGC 1 α和MITF，线粒体和黑素细胞/黑色素瘤生物发生的中心因子， 分别最近的研究，包括我们的初步结果，表明，放松管制的效应， UPR包括ATF 4、CHOP和IRE 1 α，在黑色素瘤中起着基础性作用。本P01支持的工作 确定了泛素连接酶Siah 1/2对放大UPR信号传导至关重要，并鉴定了Siah 1亚型 2（Siah 1 is 2）作为BRAFi（PLX 4032）诱导的主要亚型，并与PGC 1 α和MITF相关 表情我们的新模型是Siah 1 is 2是一个关键的传感器，它可以精细地调节ATF 4-IRE 1 α的调节作用。 轴控制PGC 1 α和MITF活动，黑色素瘤倾向的关键因素，以适应 与耐药性和转移能力相关的环境条件。协调努力 项目2和3以及核心B和C将进一步确定PGC 1 α和MITF表达和活性的调节 评估ATF 4、CHOP和Siah 1 is 2对治疗反应的贡献。为了检验这一假设 UPR和Siah 1 is 2控制的信号传导参与并微调PGC 1 α和MITF调节 网络改变代谢和转录程序，这是黑色素瘤耐药性的基础， 转移我们建议确定（i）Siah 1 is 2如何控制ATF 4-PGC 1 α-MITF调节 轴定义黑色素瘤抗性和转移表型和（ii）ATF 4/CHOP如何调节 黑色素瘤转移和耐药性？我们的研究将依赖于同类黑色素瘤，幼稚或 对治疗有抗性的同类Braf/Pten衍生的黑色素瘤系CRSPER'd的UPR和Siah 1 is 2基因，和 与Atf 4、Chop或Siah 1突变动物杂交的遗传性黑素瘤模型。我们的研究有望 导致前所未有的新的洞察力的确切作用选择普遍定期审议的组成部分发挥控制 黑色素瘤的可塑性，其潜在的耐药性和转移表型的倾向， 代表了一个关键的未满足的临床需求。

SUMMARY – PROJECT 1: SIAH1 IN ER AND MITOCHONDRIAL FUNCTION AND HOMEOSTASIS IN MELANOMA   Growing evidence indicates that activation of the adaptive unfolded protein response (UPR) occurs in melanoma cells following drug therapy. The UPR senses oxidative stress, mitochondrial dysfunction and dynamics and resolve protein misfolding in the ER, activities often deregulated in melanoma tumor cells. Notably, the degree of UPR signaling differs among melanoma subtypes, which is consistent with tumor heterogeneity and plasticity and underlies the propensity to adapt to chemotherapy and related stress stimuli. More recently, tumor resistance has been associated with altered expression and activity of the master regulators PGC1α and MITF, factors central for mitochondrial and melanocyte/melanoma biogenesis, respectively. Recent studies, including our preliminary results, demonstrate that deregulation of effectors of the UPR, including ATF4, CHOP and IRE1α, plays a fundamental role in melanoma. Work supported by this P01 established that the ubiquitin ligases Siah1/2 are critical to amplify UPR signaling and identified Siah1 isoform 2 (Siah1is2) as the major isoform induced by the BRAFi (PLX4032) and correlated with PGC1α and MITF expression. Our emerging model is that Siah1is2 is a key sensor that finely tunes the ATF4–IRE1α regulatory axis to control PGC1α and MITF activities, key elements in the propensity of melanoma to adapt to environmental conditions associated with drug resistance and metastatic capacity. Efforts coordinated with Projects 2 and 3 and Cores B and C will further define regulation of PGC1α and MITF expression and activity and evaluate the contribution of ATF4, CHOP, and Siah1is2 to therapeutic responses. To test the hypothesis that UPR- and Siah1is2-controlled signaling engages and fine-tunes the PGC1α and MITF regulatory network to alter metabolic and transcriptional programs, which underlie melanoma resistance and metastasis. We proposed to determine (i) how does Siah1is2 control of the ATF4–PGC1α–MITF regulatory axis define melanoma resistance and metastatic phenotypes and (ii) how does ATF4/CHOP regulate melanoma metastasis and drug resistance? Our studies will rely on congenic melanoma tumors, naive or resistant to therapy, congenic Braf/Pten derived melanoma lines CRSPER'd for UPR and Siah1is2 genes, and genetic melanoma models crossed with Atf4, Chop or Siah1 mutant animals. Our studies are expected to lead to unprecedented new insight into the precise role select UPR components play in control of melanoma plasticity, underlying its propensity to resistance and metastatic phenotypes—which represent a key unmet clinical need.