Defining SPINK1 as a tumor driver and therapeutic target in ovarian cancer

描述(申请人提供)：卵巢癌包括许多分子和病因上不同的疾病，但患者尚未受益于我们通过开发和翻译针对亚型的特定分子靶向治疗方法而不断发展的理解。我们假设，对于一小部分分子定义的卵巢癌患者，分泌型蛋白蛋白酶抑制剂SPINK1可能代表了肿瘤增殖、侵袭和化疗耐药的关键致癌基因驱动因素，并且SPINK1可能为这类女性提供了一个新的治疗靶点。我们进一步假设，SPINK1的这些活性不是通过抑制蛋白酶介导的，而是通过新发现的能够激活表皮生长因子受体(EGFR)的生长因子SPINK1的活性来调节的。在这里，我们提出了三个特定的目标，旨在检验这些假设。(1)利用卵巢癌细胞培养模型，结合SPINK1基因沉默和重组SPINK1治疗，明确SPINK1对卵巢癌细胞生长、侵袭和耐药的影响。我们还将测试SPINK1中和抗体抑制SPINK1阳性卵巢癌细胞的生长和侵袭的能力，以及使细胞对化疗敏感的能力。(2)我们将使用定量结合测量和X射线结晶学来定义SPINK1和EGFR之间的分子相互作用。我们还将确定EGFR信号在SPINK1在卵巢癌细胞中促癌活性中的作用。(3)我们将评估SPINK1在一大组侵袭性上皮性卵巢癌组织中的表达，测试其与EGFR信号通路激活和生存的关系。总而言之，这项工作有可能将SPINK1信号定义为以前未被识别的卵巢癌患者的恶性肿瘤的关键驱动因素，并作为新药开发的分子靶点。

DESCRIPTION (provided by applicant): Ovarian cancer encompasses many molecularly and etiologically distinct diseases, but patients have not yet benefitted from our evolving understanding through the development and translation of subtype-specific molecularly targeted therapies. We hypothesize that, for a small molecularly-defined subset of ovarian cancer patients, the secreted protein protease inhibitor SPINK1 may represent a key oncogenic driver of tumor proliferation, invasion, and chemoresistance, and that SPINK1 may offer a novel therapeutic target for this group of women. We further hypothesize that these activities of SPINK1 are mediated not through protease inhibition, but through a newly discovered activity of SPINK1 as a growth factor capable of activating the epidermal growth factor receptor (EGFR). Here, we propose three specific aims designed to test these hypotheses. (1) We will define how SPINK1 affects ovarian cancer cell growth, invasion, and drug resistance, using cell culture models of ovarian cancer in combination with SPINK1 gene silencing and recombinant SPINK1 treatment. We will also test the ability of SPINK1 neutralizing antibodies to inhibit the growth an invasion of SPINK1-positive ovarian cancer cells, and to sensitize cells to chemotherapy. (2) We will define the molecular interaction between SPINK1 and EGFR, using quantitative binding measurements and X-ray crystallography. We will also determine the role of EGFR signaling in the cancer-promoting activities of SPINK1 in ovarian cancer cells. (3) We will evaluate expression of SPINK1 in a large set of invasive epithelial ovarian cancer biospecimens, testing the association with EGFR signaling pathway activation and with survival. In aggregate, this work has the potential to define SPINK1 signaling as a key driver of malignancy for a previously unrecognized subset of ovarian cancer patients, and as a molecular target for novel drug development.