Functional and Therapeutic Significance of PLK4 in Melanoma

摘要： 这项研究的目的是确定Polo-like kinase4(Plk4)是否与其他黑色素瘤驱动因素一起 通路，是黑色素瘤治疗的可操作药物靶点，以及 Plk4在黑素细胞转化和肿瘤进展过程中的作用机制和相互作用伙伴。 黑色素瘤是一种临床上具有挑战性的皮肤癌，如果不及早诊断的话。流行病学和基因组数据 提示BRAFV600E突变可能是黑色素细胞痣的起始病变；然而，这些突变 单靠这些是不足以实现恶变的。紫外线辐射(UVR)和其他辐射的激活 已知的致癌途径有助于黑素细胞的肿瘤进展。在最近的过去， 随着批准，晚期黑色素瘤治疗的前景发生了戏剧性的变化 新药，如BRAF抑制剂和免疫检查点抑制剂。然而，这些治疗方法是 与获得性耐药性有关的患者接近50%。因此，新的机制基础上 这种可怕的肿瘤需要有效的治疗方法。基于有限的 最近的一些研究表明，Plk4被认为是治疗某些癌症的潜在药物靶点。Plk4 抑制已被证明导致中心粒和中心体复制失败，而其 过度表达会导致过量的中心粒形成，这足以驱动中心体放大。 (CA)和与致癌有关的基因组不稳定。最近的一项研究表明，Plk4在 通过调节PI3K/AKT信号通路实现上皮-间充质转化。我们最近证明了 Plk4在黑色素瘤中显著过表达，而小分子Plk4抑制导致显著 多个黑色素瘤细胞系中的抗增殖反应[摩尔癌症研究，2018年]。我们的初步数据显示 显示Plk4 CRISPR K/O A375黑色素瘤细胞在黑色素瘤中显示出明显的肿瘤生长抑制 异种移植提示Plk4在黑色素瘤中起重要作用。我们还发现联合抑制Plk4 联合抑制BRAF和MEK对黑色素瘤细胞具有协同抗增殖作用。在这项研究中，我们 提出挑战Plk4信号和其他黑素细胞驱动通路的假说 转化和肿瘤进展，将提供治疗可操作的新的联合靶向 治疗黑色素瘤的方法。提出了三个目标：1)确定两者之间的联系 Plk4和其他体外黑素细胞转化和肿瘤进展的驱动通路；2) 探讨Plk4在人黑色素瘤发生、发展和转移中的作用及机制 活体在多种人类相关的基因工程小鼠模型中的应用；3)确定治疗 Plk4抑制的意义，单独或与其他有希望的靶向抗黑色素瘤药物联合使用 活体内的模式。我们期望我们的研究将确定Plk4在黑色素瘤中的确切作用，以及它的 此肿瘤的诊断/预后及治疗意义。

SUMMARY: The objective of this study is to determine if the polo-like kinase 4 (PLK4) along with other melanoma driver pathways, is a therapeutically actionable druggable target for melanoma management, and what are the mechanisms and interacting partners of PLK4, during melanocytic transformation and neoplastic progression. Melanoma is a clinically challenging skin cancer, if not diagnosed early. Epidemiological and genomic data suggest that BRAFV600E mutations may be the initiating lesion in melanocytic nevi; however, these mutations alone are not sufficient for malignant transformation. Ultraviolet radiation (UVR) and activation of other oncogenic pathways are known to contribute to the neoplastic progression of melanocytes. In the recent past, the treatment landscape for advanced melanoma management has seen dramatic changes with the approval of new drugs such as BRAF inhibitors as well as immune-checkpoint inhibitors. However, these treatments are linked with acquired resistance occurring in nearly 50% of patients. Therefore, novel mechanism-based therapeutic approaches are needed for effective management of this dreaded neoplasm. Based on limited number of recent studies, PLK4 is being considered as a potential druggable target for certain cancers. PLK4 inhibition has been shown to cause a failure of centriole and centrosome duplication, whereas its overexpression results in excess centriole formation, which are sufficient to drive centrosome amplification (CA) and genome instability that is linked to carcinogenesis. A recent study has suggested a role of PLK4 in epithelial-mesenchymal transition (EMT) via modulating PI3K/AKT pathway. We recently demonstrated that PLK4 is significantly overexpressed in melanoma, and small molecule PLK4 inhibition resulted in a significant anti-proliferative response in multiple melanoma cell lines [Mol Cancer Res, 2018]. Our preliminary data has shown that PLK4 CRISPR K/O A375 melanoma cells show significantly decreased tumor growth in melanoma xenografts suggesting an important role of PLK4 in melanoma. We also found that combined inhibition of PLK4 with BRAF and MEK inhibition exerted synergistic antiproliferative effect in melanoma cells. In this study, we propose to challenge a hypothesis that PLK4 signaling, together with other driver pathways of melanocytic transformation and neoplastic progression, will provide therapeutically-actionable novel co-targeting approaches, for melanoma management. Three aims are proposed to; 1) determine the association between PLK4 and other driver pathways of melanocytic transformation and neoplastic progression ex vivo; 2) determine the functional and mechanistic significance of PLK4 in melanoma progression and metastasis in vivo in a variety of human-relevant genetically engineered mouse models; 3) determine the therapeutic significance of PLK4 inhibition, alone and in combination with other promising target-based anti-melanoma modalities in vivo. We expect that our study will establish the exact role of PLK4 in melanoma, and its diagnostic/prognostic as well as therapeutic significance in this neoplasm.