Targeting Rheostatic Mechanisms of Melanoma Progression

皮肤黑色素瘤是高度致命的，是美国第五大常见癌症。 老年人，但老年人，年轻人，甚至儿童受到影响。在所有癌症类型中，黑色素瘤是 在极早期转移的倾向中是最具侵略性的。转移性黑色素瘤很难 迫切需要新的治疗方法来限制疾病的进展。黑色素瘤的遗传原因 沿着RAS蛋白信号传导的连续体排列，其中BRAFV 600 E突变是最常见的驱动因素。的 突变型BRAFV 600 E蛋白依赖于MAPK信号传导来启动和维持肿瘤生长。 用RAF和MEK抑制剂靶向这种异常激活的通路在治疗糖尿病方面取得了有限的成功。 这种疾病是由于MAPK信号重新激活，引起耐药性。因此，更机械的见解是 为了开发出能够规避耐药性的联合疗法，我们报告说， 控制细胞内运输的蛋白质小GTP酶ARF 6的激活，加速了肿瘤的转移。 BRAFV 600 E黑素瘤。在转移之前，我们未发表的数据显示，蛋白ARF 6也是转移所必需的。 在具有BRAFV 600 E黑素瘤的小鼠中有效的肿瘤发展和生长。这将ARF 6定位为关键 在疾病进展的多个点调节。事实上，我们的初步数据表明，ARF 6的新作用 通过调节活化的磷酸化ERK的核定位，在MAPK信号传导中起作用，磷酸化ERK是MAPK信号传导的关键效应蛋白， BRAF。因此，我们假设ARF 6调节BRAFV 600 E介导的肿瘤进展，控制MAPK 信号传导并提供用于肿瘤生长和转移的药理学抑制的脆弱节点。 使用遗传和药理学方法，包括我们独特的小鼠模型和特定的ARF 6抑制剂 我们的目标是剖析ARF 6在MAPK信号传导中的作用，发现ARF 6在MAPK信号传导中的新作用， ARF 6在肿瘤细胞功能中的作用，并测试ARF 6抑制剂在限制肿瘤进展中的功效。根据 为了实现这些目标，我们将：1）检验ARF 6控制BRAFV 600 E-黑色素瘤中MAPK信号传导的假设; 2）检验 ARF 6对BRAFV 600 E黑色素瘤的增殖和存活至关重要的假设; 3）检验假设 ARF 6的药理学抑制在BRAFV 600 E黑色素瘤患者源性 异种移植物（MPDX）。成功完成本提案中的目标将确定新的机制， 黑色素瘤进展，适合治疗干预，并可能定位ARF 6作为一个潜在的 RAS突变型癌症的治疗靶点。

Cutaneous melanoma is highly lethal and the fifth most common cancer in the U.S. Peak incidence is in middle age adults but the elderly, young adults and even children are affected. Among all cancer types, melanoma is one of the most aggressive in its propensity for extremely early metastasis. Metastatic melanoma is difficult to eradicate and new therapies are urgently needed to limit disease progression. Genetic causes of melanoma align along a continuum of RAS protein signaling whereby BRAFV600E mutation is the most common driver. The mutant BRAFV600E protein depends on MAPK signaling for both initiation and maintenance of tumor growth. Targeting this abnormally-activated pathway with RAF and MEK inhibitors have had limited success in treating this disease due to MAPK signaling reactivation, causing drug resistance. Thus, more mechanistic insights are needed in order to develop combination therapies that can circumvent resistance. We reported that aberrant activation of the small GTPase ARF6, a protein that controls intracellular trafficking, accelerates metastasis of BRAFV600E melanoma. Prior to metastasis, our unpublished data reveal that the protein ARF6 is also required for efficient tumor development and growth in mice with BRAFV600E melanoma. This positions ARF6 as a key regulator at multiple points in disease progression. Indeed, our preliminary data suggest a novel role for ARF6 in MAPK signaling by regulating the nuclear localization of activated, phospho-ERK, a key effector protein for BRAF. Thus, we hypothesize that ARF6 modulates BRAFV600E-mediated tumor progression, controlling MAPK signaling and providing a vulnerable node for pharmacologic inhibition of both tumor growth and metastasis. Using genetic and pharmacologic approaches, including our unique mouse models and a specific ARF6 inhibitor that we helped develop, our goals are to dissect the roles of ARF6 in MAPK signaling, discover new role(s) for ARF6 in tumor cell function, and test the efficacy of ARF6 inhibitors in restricting tumor progression. Pursuant to these goals, we will: 1) Test the hypothesis that ARF6 controls MAPK signaling in BRAFV600E-melanoma; 2) Test the hypothesis that ARF6 is critical for proliferation and survival of BRAFV600E melanoma; 3) Test the hypothesis that pharmacologic inhibition of ARF6 has therapeutic efficacy in BRAFV600E melanoma patient-derived xenografts (MPDX). Successful completion of the aims in this proposal will identify new mechanisms of melanoma progression that are amenable to therapeutic intervention and may position ARF6 as a potential therapeutic target in RAS-mutant cancers.