Role of CCL25-CCR9 in Prostate Cancer

描述（由申请人提供）：尽管最近在前列腺癌（PCa）治疗药物的临床设备中增加了激素难治性转移性疾病，但绝大多数（约90%）PCa死亡伴骨转移，特别是骨转移。大多数目前可用的用于PCa的化疗方案（包括多西他赛）基本上非选择性地靶向快速分裂的细胞群，因此呈现使人衰弱的毒性。其他主要限制是由于雄激素非依赖性的出现以及转移性疾病的较低增殖能力。因此，鉴定由较少增殖的， 雄激素非依赖性转移性前列腺癌细胞可能导致这种可怕疾病的几乎完全消除。趋化因子-配体轴在肿瘤细胞运输和器官特异性转移的发展中起着至关重要的作用。我们的实验室是第一个表明CC趋化因子受体9（CCR 9）在前列腺癌中选择性过表达，而在正常前列腺上皮中的表达可忽略不计。我们最近发表的和初步的数据表明：1）CCR 9由PCa细胞高度表达，并介导PCa细胞的体外迁移、侵袭和存活，2）CCR 9在临床前列腺癌组织样品中也高度表达，3）CCL 25，CCR 9的天然配体，由PCa临床样品以旁分泌方式表达，并在PCa患者血清中也升高，4）荷瘤小鼠骨髓基质细胞产生CCL 25的能力显著高于非荷瘤小鼠。5）抑制CCR 9-CCL 25轴可使PCa细胞对化疗的反应敏感。基于这些令人鼓舞的数据，我们假设CCR 9-CCL 25轴在前列腺癌转移中起关键作用，并且是癌症选择性治疗靶点。靶向这一轴将使新的化疗策略的发展，以及改善现有的敏感性前列腺癌细胞目前可用的方案。为了验证我们的假设，我们提出确定CCR 9-CCL 25轴在（i）诱导前列腺癌细胞迁移和侵袭，（ii）前列腺癌细胞存活和凋亡，（iii）触发前列腺癌生长和转移iv）增强临床方案的化疗功效中的作用。为了实现我们的目标，我们已经产生了CCR 9条件性敲除细胞，其将用于体外测定以确定其在PCa细胞迁移、侵袭和存活中的作用，并确定其在肿瘤生长、转移和多西他赛治疗功效中的潜在作用。此外，针对CCR 9驱动的信号分子的siRNA双链体或特异性药理学抑制剂将用于评估CCR 9-CCL 25轴在促进转移中的作用。我们乐观地认为，这些研究的成功完成将确定这种新发现的趋化因子在PCa中的作用， 大大有助于我们理解趋化因子在介导疾病侵袭性方面的作用。此外，它将能够设计和开发针对PCa的CCR 9-CCL 25轴的合理疗法。

DESCRIPTION (provided by applicant): Despite recent additions in the clinical armamentarium of drugs for prostate cancer (PCa) therapy, hormone refractory metastatic disease accounts for an overwhelming majority (~90%) of PCa deaths with skeletal metastases, particularly in bones. Most currently-available chemotherapeutic regimens for PCa including docetaxel essentially target rapidly dividing cell populations non-selectively, thus presenting debilitating toxicities. Other major limitations are owing to the emergence of androgen-independence as well as lower proliferative capacity of the metastatic disease. Thus, identification of novel molecular targets that are selectively presented by the less-proliferative, androgen-independent metastatic prostate cancer cells might result in the near-complete elimination of this dreaded disease. It is becoming well appreciated that the chemokine-ligand axis is crucially involved in tumor cell trafficking and the development of organ-specific metastases. Our laboratory is the first to show that CC chemokine receptor 9 (CCR9) is selectively over expressed in prostate cancers with negligible expression in normal prostate epithelia. Our recently published and preliminary data demonstrate that 1) CCR9 is highly expressed by PCa cells and mediates PCa cell migration, invasion and survival in vitro, 2) CCR9 is also highly expressed in clinical prostate cancer tissue samples, 3) CCL25, a natural ligand of CCR9, is expressed in a paracrine manner by PCa clinical sample and also elevated in PCa patient serum, 4) bone marrow stromal cells of tumor-bearing mice significantly produce CCL25, compared to non-tumor bearing ones, 5) inhibition of CCR9-CCL25 axis sensitizes cellular responses to chemotherapy in PCa cells. Based upon these encouraging data, we hypothesize that CCR9-CCL25 axis plays a crucial role in prostate cancer metastasis and is a cancer-selective therapeutic target. Targeting this axis will enable development of new chemotherapeutic strategies as well as improving existing ones by sensitizing prostate cancer cells to currently available regimens. To validate our hypothesis, we propose to determine the role of CCR9-CCL25 axis in (i) inducing prostate cancer cell migration and invasion, (ii) prostate cancer cell survival and apoptosis, (iii) triggering prostate cancer growth and metastases iv) enhancing chemotherapeutic efficacy of clinical regimens. To accomplish our aims, we have generated CCR9 conditional knockout cells that will be used for in vitro assays to determine its role in PCa cell migration, invasion and survival, and determining its potential role in tumor growth, metastasis and therapeutic efficacy of docetaxel. In addition, siRNA duplexes or specific pharmacological inhibitors against CCR9 driven signaling molecules will be used to evaluate the role of CCR9-CCL25 axis in promotion of metastases. We are optimistic that the successful completion of these studies will define the role of this newly identified chemokine in PCa and will go a long way to enhance our understanding of chemokines in mediating disease aggressiveness. Furthermore, it will enable the design and development of rational therapies directed against the CCR9-CCL25 axis for PCa.