Role of polo like kinase 4 in melanomagenesis and melanoma progression

总结： 黑色素瘤是最具侵袭性的人类癌症之一，约有87，110例新发黑色素瘤病例 2017年美国预计将有9,730例黑色素瘤相关死亡。此外，黑色素瘤是一个重要的问题， 在退伍军人。美军目前正在并一直在世界各地执行任务，包括 最近，在中东（伊拉克和阿富汗）。许多美国军事人员，谁是部署到高 热带和亚热带地区的紫外线（UV）指数气候可能具有更高的黑色素瘤风险。 此外，这些人员没有得到充分的保护，因为他们可能有其他生存优先事项， 避免紫外线照射。根据退伍军人事务部中央癌症登记处（VACCR），黑色素瘤是 VA癌症患者中最常诊断的五种癌症。 不幸的是，现有的治疗策略要么未能实现>25%的响应， 反应是短暂的，并对治疗产生耐药性。事实上，最近在理解方面的进展 黑色素瘤生物学的发展导致了靶向治疗的发展，如BRAF抑制剂（维罗非尼 和达拉非尼）在具有BRAF突变的黑色素瘤的化疗中获得了改善。然而，在这方面， 即使使用这些新的靶向方法，大多数患者也会产生耐药性，从而无法实现 持续的肿瘤消退因此，需要进一步的研究来了解黑色素瘤的发病机制 发展和进步。Polo样激酶4（PLK 4），一种丝氨酸/苏氨酸激酶，是细胞凋亡的主要调节因子。 中心粒重复PLK 4是一种低丰度的自杀激酶，已知其自身磷酸化， 促进其自身的破坏以限制中心粒在每个细胞周期复制一次。根据最近的研究，PLK 4是 成为癌症治疗的潜在靶点。PLK 4被建议参与某些 癌的有趣的是，PLK 4的过表达已被证明会导致额外的中心体， 转基因小鼠和胃癌细胞中初级纤毛的丧失。重要的是，初级纤毛存在于黑素细胞中 并且经常在黑色素瘤中丢失。虽然关于PLK的潜在作用的信息有限4 在某些癌症中，其在黑色素瘤发展和进展中的作用尚未得到评价。在我们 初步数据，我们发现PLK 4在黑色素瘤细胞和人体组织中过表达（在有限的时间内）。 研究的样本数量），其通过小分子抑制剂centrinone B的抑制导致 在多种人黑素瘤细胞系中的显著抗增殖应答。因此，根据现有的 根据文献和我们的初步数据，我们建议检验PLK 4在以下假设中起关键作用： 黑色素瘤的发展和进展，并可以作为黑色素瘤管理的新目标。的 提出了以下具体目的：1）确定PLK 4在黑素瘤发生和进展中的作用， 采用从退伍军人患者的回顾性黑素瘤组织创建的组织微阵列（TMA），以及 体外细胞转化模型; 2）确定PLK 4在细胞转化中的功能和机制意义。 黑色素瘤（下游机制和对纤毛形成的影响）; 3）确定 PLK 4在黑素瘤的人相关小鼠模型中的治疗意义，即， Braftm 1 Mmcm Ptentm 1Hwu Tg（Tyr-cre/ERT 2）13 Bos/BosJ模型和患者来源的异种移植物（PDX）模型。这 可能最终导致黑色素瘤的新诊断、预后或治疗方法的发展。 由于退伍军人人群中黑色素瘤的发病率似乎较高，我们提出的研究旨在 确定黑色素瘤发展的分子机制可能会导致识别新的策略， 这种致命肿瘤的治疗因此，我们建议的工作对《公约》的执行具有相关性和重要性。 退伍军人的医疗保健，并符合退伍军人事务部的使命。

SUMMARY: Melanoma is one of the most aggressive human cancers with approximately 87,110 new melanoma cases and 9,730 melanoma-related deaths predicted in the U.S. in 2017. Further, melanoma is a significant problem in Veterans. The US military currently is and has been engaged, in missions all over the world, including recently, in the Middle East (Iraq and Afghanistan). Many US military personnel, who are deployed to high ultraviolet (UV) index climates in tropical and subtropical zones are potentially at a higher risk for melanoma. Further, these personnel are not adequately protected because they possibly have survival priorities other than avoiding UV exposure. Based on the Veterans Affairs Central Cancer Registry (VACCR), melanoma is among the five most frequently diagnosed cancers among VA cancer patients. Unfortunately, the available therapeutic strategies have either failed to achieve >25% response or the responses are short-lived with developing resistance to therapy. Indeed, recent advances in the understanding of melanoma biology has led to the development of targeted therapies such as BRAF inhibitors (vemurafenib and dabrafenib) achieved improvement over chemotherapy for melanomas with BRAF-mutations. However, even with these new targeted approaches, most of the patients develop resistance, thereby failing to achieve lasting tumor regression. Therefore, further research is needed to understand the mechanism of melanoma development and progression. Polo-like kinase 4 (PLK4), a serine/threonine kinase, is the master regulator of centriole duplication. PLK4 is a low abundance suicidal kinase that is known to autophosphorylate itself to promote its own destruction to limit centriole duplication once per cell cycle. Based on recent research, PLK4 is emerging as a potential target for cancer treatment. PLK4 has been suggested to be involved in certain cancers. Interestingly, overexpression of PLK4 has been shown to result in supernumerary centrosomes and loss of primary cilia in transgenic mice and gastric cancer cells. Importantly, primary cilia exist in melanocytes and frequently lost in melanoma. Although limited information is available regarding the potential role of PLK4 in certain cancers, its involvement in melanoma development and progression has not been evaluated. In our preliminary data, we have found that PLK4 is overexpressed in melanoma cells and human tissues (in a limited number of specimens studied) and its inhibition via a small molecule inhibitor centrinone B results in a significant anti-proliferative response in multiple human melanoma cell lines. Thus, based on available literature and our preliminary data, we propose to test the hypothesis that PLK4 plays a critical role in melanoma development and progression and could serve as a novel target for melanoma management. The following specific aims are proposed; 1) to define the role of PLK4 in melanoma development and progression, employing a tissue microarray (TMA) created from retrospective melanoma tissues from Veteran patients, and an in vitro cell transformation model; 2) to determine the functional and mechanistic significance of PLK4 in melanoma (downstream mechanisms and effect on cilia formation), in vitro and in vivo; 3) to determine the therapeutic significance of PLK4 in melanoma in human-relevant mouse models of melanoma, namely, Braftm1Mmcm Ptentm1Hwu Tg(Tyr-cre/ERT2)13Bos/BosJ model and patient-derived xenografts (PDX) model. This may ultimately lead to development of novel diagnostic, prognostic or therapeutic approaches for melanoma. Since melanoma incidence seems to be higher in the Veteran population and our proposed study aimed at defining the molecular mechanism of melanoma development may lead to identification of novel strategies for the management of this deadly neoplasm. Therefore, our proposed work is relevant and significant to the health care of Veterans and is in line with the mission of the Department of Veteran Affairs.