Erythropoietin and Breast Cancer Stem Cells

描述(申请人提供)：这项研究探索辐射和促红细胞生成素(EPO)是否协同改变乳腺癌干细胞(BCSCs)的自我更新，并将分化的乳腺癌(BC)细胞重新编程为诱导的乳腺癌干细胞(IBCSCs)。利用已建立的细胞系和对接受放射治疗(RT)的乳腺癌患者的乳腺癌干细胞、患者来源的肿瘤样本和临床预处理血液样本进行成像的独特系统，它将探索EPO是否直接作用于辐射后的BCSC，是否改变BCSC的NICH，以及在EPO存在的情况下，在辐射诱导分化的BC细胞重新编程过程中参与了哪些途径。在一项前瞻性的临床研究中，我们将测试高血清EPO水平是否与保乳手术(BCS)和放疗后的BCSC负荷、结节状态和局部控制相关。我们假设，电离辐射将分化的乳腺癌细胞重新编程为耐辐射的iBCSCs，内源性EPO与辐射协同作用增加BCSCs池，从而损害放射治疗结果。局限性乳腺癌通常采用乳房切除术或BCS+RT治疗。对于RT，低血红蛋白(Hb)水平预示着早期治疗失败。试图使用EPO提高Hb水平会导致BC患者预后较差，这表明通过EPO受体传递的信号促进了肿瘤的生长。最近的研究表明，BCs是由一小群BCSC层级组织起来的，能够重新生长肿瘤，而他们的后代缺乏这一特征。根据肿瘤干细胞(CSC)假说，只有消除所有的CSCs才有可能治愈，这表明EPO的有害作用是通过EPO对BCSCs的作用来实现的。由于BCSCs的稀有性质，EPO对这些细胞的影响尚未被研究。BCSC的辐射抗性相对较强。此外，EPOR在肿瘤细胞上的表达与预后呈负相关，rh Epo和RT在体外可能通过RT诱导分化的BC细胞重编程为iBCSC而增加BCSCs的数量。这一假设将通过1)研究EPO和RT对BCSCs的影响，2)探索在重编程过程中激活的通路，以及3)测试内源性EPO是否在临床上影响BCSCs来验证。癌症相关性贫血是癌症患者中发病率较高的疾病。这项提案将研究是否 促红细胞生成素激活与放射协同作用的通路，以增加耐药的BCSCs池，并评估内源性EPO水平是否与BCSC负担和临床结果相关。这项建议的长期目标是研究在什么情况下EPO会干扰BCSC数量和治疗结果。了解这些途径可能会导致新的联合治疗方法，从而改善BC的治疗结果。

DESCRIPTION (provided by applicant): This study explores if radiation and erythropoietin (Epo) synergize to alter the self-renewal of breast cancer stem cells (BCSCs) and to reprogram differentiated breast cancer (BC) cells into induced breast cancer stem cells (iBCSCs). Using established cell lines and a unique imaging system for breast cancer stem cells, patient-derived tumor samples and clinical pretreatment blood samples of BC patients undergoing radiation treatment (RT) it will explore if Epo acts on irradiated BCSCs directly, if it alters the BCSC nich, and which pathways are engaged during radiation-induced reprogramming of differentiated BC cells in the presence of Epo. In a prospective clinical study we will test, if high serum Epo level correlate with high BCSC burden, nodal status and local control after breast-conserving surgery (BCS) and RT. We hypothesize, that ionizing radiation reprograms differentiated breast cancer cells into radioresistant iBCSCs and that endogenous Epo synergizes with radiation to increase the BCSCs pool, thereby impairing radiation therapy outcome. Limited stage BC is usually treated with mastectomy or BCS and RT. For RT, low hemoglobin (Hb) levels predict early treatment failure. Attempts to increase Hb levels using Epo led to inferior outcome of BC patients, suggesting that signaling through the Epo receptor promotes tumor growth. Recent studies indicate that BCs are organized hierarchically with a small population of BCSCs, capable of re-growing a tumor while their progeny lack this feature. According to the cancer stem cell (CSC) hypothesis, cure is only possible if all CSCs are eliminated, suggesting that the deleterious effects of Epo were mediated by effects of Epo on BCSCs. Because of the rare nature of BCSCs, the effects of Epo on these cells have not been investigated. BCSCs are relatively radioresistant. Furthermore, EpoR expression on tumor cells is inversely correlated with prognosis and rhEpo and RT increases the number of BCSCs in vitro possibly through RT-induced reprogramming of differentiated BC cells into iBCSCs. The hypothesis will be tested by 1) investigating the effects of Epo and RT on BCSCs, 2) exploring the pathways activated during reprogramming, and 3) testing if endogenous Epo affects BCSCs clinically. Cancer-related anemia is a condition with a high incidence in cancer patients. This proposal will study if erythropoietin activates pathways that synergize with radiation to increase the pool of therapy-resistant BCSCs and evaluate if endogenous Epo level correlate with BCSC burden and clinical outcome. The long-term goals of this proposal are to study under which circumstances Epo interferes with BCSC numbers and treatment outcome. Understanding the pathways may lead to novel combined treatments that will improve BC treatment outcome.