Characterization of NYP Peptides in Prostate Cancer

摘要 肥胖与高级别前列腺癌（PC）、治疗后复发、转移和 PC死亡我们利用肥胖和侵袭性前列腺之间的联系来确定可操作的目标。本 最后，我们在肥胖小鼠中进行了靶向整个激酶组的shRNA基因组筛选。我们的屏幕显示 右开放阅读框架激酶2（RIOK 2），作为肥胖小鼠中有前途的PC靶点，并表明 核糖体生物合成在PC中起作用。我们随后的研究已经确定了非核糖体RIOK 2功能 将神经肽Y（NPY），一种与进食行为和肥胖有关的神经递质，与PC细胞生物学联系起来。 我们发现RIOK 2调节五种已知哺乳动物神经肽Y之一的神经肽Y2受体（NYP 2 R 命名为Y1至Y 5的受体，其与NPY结合。在机制上，RIOK 2结合NPY 2 R启动子 RIOK 2的缺失显著降低了NPY 2 R的表达。我们在PC细胞中发现了NPY 2 R的敲低， 在体外抑制PC细胞的增殖并降低其致瘤性。NPY，即NPY 2 R配体，主要是 下丘脑神经元产生，但男性生殖道也表达神经支配分泌的NPY， 包括在前列腺和前列腺周围脂肪细胞中。NPY在PC中进一步上调（~50倍）。事实上，NPY是一种 报告的PC生物标志物。然而，目前还不清楚这种神经递质是否在PC发育中发挥生物学作用， 进展增加不确定性的是，全长36个氨基酸的NPY 1 -36容易被切割成NPY 3 -36， 它是二肽基肽酶IV（DPP 4）的选择性NPY 2 R激动剂，膜蛋白酶也高度表达 在PC中。因此，NPY 3 -36可能占PC中NPY肽的很大一部分，这可能引起不同的信号传导 与全长NPY 1 -36相比，NPY 1 -36主要通过NPY 2 R引起的事件。然而，前列腺血清抗原又称激肽3， 前列腺血清生物标志物也是一种可作用于NPY的肽酶。我们的总体假设是， 容易被前列腺肽酶切割，并且NPY肽片段在PC中起作用。机械地说， 我们假设NPY被前列腺DPP 4和/或PSA切割，并且前列腺NPY切割肽具有 与全长NPY相比，差异下游信号级联和表型效应。为了验证这一 假设我们将（目的1）鉴定和表征前列腺NPY切割肽，（目的2）测试NPY是否 水平改变体内和离体人PC中的PC发育。

ABSTRACT Obesity is linked with greater risk of high-grade prostate cancer (PC), recurrence after therapy, metastases, and PC death. We exploited the link between obesity and aggressive prostate to identify actionable targets. To this end, we performed a shRNA genomic screen in obese mice targeting the entire kinome. Our screen identified Right Open Reading Frame Kinase 2 (RIOK2), as a promising PC target in obese mice and suggests that ribosomal biogenesis plays a role in PC. Our subsequent studies have identified non-ribosomal RIOK2 functions that link Neuropeptide Y (NPY), a neurotransmitter involved in feeding behavior and obesity, with PC cell biology. We found RIOK2 regulates Neuropeptide Y2 Receptor (NYP2R), one of five known mammalian neuropeptide Y receptors designated Y1 through Y5, which bind to NPY. Mechanistically, RIOK2 binds the NPY2R promoter and depletion of RIOK2 significantly reduces NPY2R expression. We found knockdown of NPY2R in PC cells, inhibits proliferation and reduces tumorigenic properties of PC cells in vitro. NPY, the NPY2R ligand, is chiefly produced in hypothalmic neurons, yet the male genital track also expresses NPY secreted from innervation, including in prostate and periprostatic adipocytes. NPY, is further upregulated in PC (~50 fold). In fact, NPY is a reported PC biomarker. Yet, it is unclear if this neurotransmitter plays a biological role in PC development or progression. Adding to the uncertainty, the full length 36 amino acid NPY1–36 is readily cleaved to NPY3–36, making it a selective NPY2R agonist by a dipeptidyl peptidase IV (DPP4), a membrane protease is also highly expressed in PC. Thus, NPY3-36 likely accounts for a large portion of NPY peptides in PC, which may elicit distinct signaling events compared to full length NPY1-36 primarily via NPY2R. However, prostate serum antigen aka kallikerin 3, a prostate serum biomarker is also a peptidase that may act on NPY. Our overarching hypothesis is that NPY is readily cleaved by prostatic peptidases and NPY peptide fragments play a role in PC. Mechanistically, we hypothesize that NPY is cleaved by prostatic DPP4 and/or PSA, and prostatic NPY cleavage peptides have differential downstream signaling cascades and phenotypic effects compared to full length NPY. To test this hypothesis we will (Aim 1) identify and characterize prostatic NPY cleaved peptides and (Aim 2) test if NPY levels alter PC development in vivo and in ex vivo human PCs.