ELR-CXC chemokines: regulators of tumour progression

在受前列腺炎性疾病影响的狗中，前列腺癌的发病率比一般人群显著升高(5-7%)。患有转移性前列腺癌的狗的预后与人类没有什么不同--进展有时可以减缓，但我们现在使用的任何方法都不能减轻它。与人类的情况不同，我们对犬类肿瘤的免疫生物学知之甚少。许多G蛋白偶联受体(例如，CXCR1、CXCR2)直接参与了人类前列腺癌的进展，但其中一些也可以反式激活无关的生长因子受体(例如，EGF-R)，从而促进肿瘤的进展。我们知道，在人类肿瘤中，ELR-CXC趋化因子(例如，CXCL8)以多种方式促进肿瘤生长、血管生成、转移和对化疗药物的发展耐药，并且它们的表达在至少部分犬癌中表达升高，并预测预后。这表明，这些介体同样可以在狗的癌症的细胞和分子生物学中发挥重要作用。-我们的实验室开发了一种抗炎剂，牛‘G31P’，它拮抗ELR-CXC趋化因子的CXCR1和CXCR2受体，但与任何竞争对手CXCR1/CXCR2拮抗剂不同，它也减敏或抑制CXCR1/R2阳性细胞中无关GPCR(例如，C5aR)的激活。G31P在许多炎症模型中具有相当戏剧性的病理保护作用，但在异种免疫低下的SCID(免疫低下)小鼠模型中，它也~90%地减少了人PC-3前列腺癌的进展。因此，我们现在有了一些重要的新工具，可以用来询问ELR-CXC趋化因子的基本生物学。-我们的计划旨在探索这些趋化因子在犬癌中的作用，特别是评估CXCR1/CXCR2拮抗是否会阻止肿瘤进展。这一目标的实现将有助于在这一鲜为人知的犬类生物学领域提供基础知识。我们推测ELR-CXC趋化因子是狗肿瘤发生的基石，在1)原发肿瘤生长、2)血管生成和3)化疗耐药性的形成中具有深远的影响。我们将使用犬前列腺癌/SCID小鼠模型、已建立的犬前列腺癌细胞系和从肿瘤临床捐赠者那里获得的细胞来解决这些方面的每一个方面。具体地说，我们将利用犬和小鼠宿主PCR阵列、qRT-PCR和/或ELISA法绘制肿瘤细胞表达或诱导ELR-CXC趋化因子及其受体以及其他与肿瘤相关的GPCR受体及其配体的局部表达的水平。还将评估肿瘤细胞分泌血管生成因子的能力，以及这些趋化因子和异源gpr对肿瘤中这些过程的贡献。我们还将通过分析细胞因子、趋化因子和趋化因子受体的使用来证实它们在原发肿瘤进展中的作用。我们将绘制相关异源GPCR在肿瘤中的活性图谱，并评估它们的沉默是否改变了肿瘤生物学。细胞毒素耐药性的产生是癌症治疗中的一个主要因素；因此，我们将研究这些趋化因子在其中的作用，确定它们的拮抗作用是否有利于癌症化疗结果，以及这些过程背后的细胞和分子机制。-这些信息将为肿瘤生物学和ELR-CXC趋化因子在狗身上的生物学提供重要的新见解，并可能导致发现癌症治疗的新途径。拟议中的计划将为一些下一代研究人员提供培训，并可能为犬类免疫生物学研究打开一扇全新的大门。

Among dogs affected with prostatic inflammatory diseases, the incidence of prostate cancer is substantially elevated (5-7%) relative to the general population. The prognosis for dogs with metastatic prostate cancer is not unlike that in humans - progression can sometimes be slowed, but it is not abated by any of the approaches we now use. Unlike the human condition, we know little about the immunobiology of canine tumours. A number of G protein-coupled receptors (GPCR; e.g., CXCR1, CXCR2) have been directly implicated in human prostate tumour progression, but some of these can also transactivate unrelated growth factor receptors (e.g., EGF-R) that also foster tumour progression. We know that with human tumours the ELR-CXC chemokines (e.g., CXCL8) contribute in multiple ways to tumour growth, angiogenesis, metastasis, and the development resistance to chemotherapeutic agents, and their expression is both elevated in and prognostic of outcomes with at least some canine cancers. This suggests that these mediators could similarly play important roles in the cellular and molecular biology of cancer in dogs. - Our lab developed an anti-inflammatory agent, bovine `G31P', that antagonizes the CXCR1 and CXCR2 receptors for the ELR-CXC chemokines but, unlike any competitor CXCR1/CXCR2 antagonists, it also desensitizes or dampens activation of unrelated GPCR (e.g., the C5aR) in CXCR1/R2-positive cells. G31P has rather dramatic pathology-sparing effects in numerous models of inflammation, but it also ~90% reduces human PC-3 prostate cancer progression in a xenogeneic SCID (immunocompromised) mouse model. Thus, we now have some important new tools with which we can interrogate the basic biology of the ELR-CXC chemokines. - Our program is designed to explore the roles of these chemokines in canine cancer, specifically assessing whether CXCR1/CXCR2 antagonism will block tumour progression. Realization of this objective will contribute foundational knowledge in this largely unknown area of canine biology. We hypothesize that the ELR-CXC chemokines are cornerstones of tumourigenesis in dogs, having profound effects in i) primary tumour growth, ii) angiogenesis, and iii) the development of resistance to chemotherapics. We will address each of these facets using a canine prostate cancer/SCID mouse model, established canine prostate tumour cell lines and cells obtained from oncology clinic donors. Specifically, we will map the levels at which tumour cells express or induce local expression of ELR-CXC chemokines and their receptors, as well as other tumour-relevant GPCR receptors and their ligands by use of canine and mouse host PCR array, qRT-PCR and/or ELISA assays. The abilities of the tumour cells to secrete angiogenic factors will also be assessed, as will the contributions of these chemokines and heterologous GPCR to these processes in tumours. We will also confirm that they contribute to primary tumour progression, analyzing cytokine, chemokine & chemokine receptor useage. We will map the activity of relevant heterologous GPCR in tumours and assess whether their silencing changes tumour biology. Development of resistance to cytotoxins is a major confounder in cancer therapy; as such we will examine the roles of these chemokines therein, determining whether their antagonism will benefit cancer chemotherapeutic outcomes, as well as the cellular and molecular mechanisms underlying these processes. - This information will provide important new insights into the biology of tumours and ELR-CXC chemokines in dogs, and potentially lead to new avenues of discovery in cancer therapy. The proposed program will provide training for a number of next-generation researchers and potentially open an entirely new door in canine immunobiology research.