Mechanism and Prevention of Doxorubicin-Induced Lymphedema

项目摘要/摘要 淋巴水肿是乳腺癌放疗和/或手术后的主要并发症。不幸的是，在那里 没有有效治疗它的药物。严重的并发症包括疼痛、淋巴管炎、蜂窝织炎、溃疡和 恶性淋巴管肉瘤的发展。阿霉素(DOX)是一种中枢化疗药物 治疗乳腺癌，但它会使淋巴水肿的风险增加4-5倍。DOX的作用机制 淋巴水肿的发生原因尚不清楚，但被认为与其细胞毒作用有关。 然而，我们认为临床浓度的DOX直接抑制淋巴的节律性收缩。 血管(LV)，推动淋巴液从组织回到心脏，以防止淋巴水肿。这些宫缩 受到LV中钙浓度和氧化还原状态的严格控制。高分辨率活体成像也 结果显示，全身给药的DOX显著减少了淋巴流量。左心室收缩功能的抑制 DOX的作用在很大程度上被临床上可用的兰诺定阻断剂丹曲林(Dantrolene，DANT)所阻止 受体(RYRs)和线粒体特异性活性氧(MitoROS)清除剂MitoTEMPO。 这些数据，以及DOX激活RYRs和诱导纹状体线粒体功能障碍的知识 肌肉和最近在LV中发现的功能性RYR，让我们假设：DOX敏锐地打开 RYRs增加淋巴肌细胞(LMCs)胞浆钙和有丝分裂原，导致 左室收缩，并引起淋巴淤滞和淋巴损伤。因此，我们将探讨是否 Dant是FDA批准的RyR阻滞剂，可以预防DOX引起的淋巴功能障碍。三个目标将 使用综合技术来探索这一假说，并将依赖于蛋白质和功能分析 分离的淋巴肌肉细胞和整个LV，使用光学成像评估体内的体积淋巴流量 对DOX和RyR阻滞剂的反应，并研究DANT作为一种潜在的治疗方法在大鼠乳腺中的应用 肿瘤模型。目标1将量化RyR亚型的基因和蛋白质表达谱并确定 DOX是否激活RYRs增加胞浆钙和有丝分裂原的生成作为一种机制 抑制左心室收缩。Aim 2将评估DANT是否代表着预防DOX的潜在治疗选择- 诱导抑制淋巴流动，预防DOX所致淋巴损伤。目标3将调查这些影响 DANT对DOX在乳腺癌大鼠模型中抗癌活性的影响。因此，我们计划探索RYR作为 DOX相关性淋巴水肿的新治疗靶点和评价RyR阻滞剂是否可以改变用途 作为抗淋巴浮肿的药物。

PROJECT SUMMARY/ABSTRACT Lymphedema is a major complication after radiation and/or surgery for breast cancer. Unfortunately, there are no medications to effectively treat it. Serious complications include pain, lymphangitis, cellulitis, ulcers, and the development of malignant lymphangiosarcomas. Doxorubicin (DOX) is a central chemotherapeutic agent for treating breast cancer, but it increases the risk of lymphedema by 4- to 5-fold. The mechanism by which DOX contributes to the development of lymphedema is unknown, but it is thought to relate to its cytotoxic action. However, we propose that clinical concentrations of DOX directly inhibit the rhythmic contractions of lymph vessels (LVs) that propel lymph fluid from tissues back to the heart to prevent lymphedema. These contractions are tightly controlled by the calcium concentration and redox state in LVs. High-resolution in vivo imaging also reveals that systemically administered DOX profoundly reduces lymph flow. The suppression of LV contractile function by DOX is largely prevented by both dantrolene (DANT), a clinically available blocker of ryanodine receptors (RYRs), and MitoTEMPO, a mitochondrial-specific reactive oxygen species (mitoROS) scavenger. These data, along with knowledge that DOX activates RYRs and induces mitochondrial dysfunction in striated muscle and recent discoveries of functional RYRs in LVs, have led us to hypothesize that: DOX acutely opens RYRs to increase cytosolic calcium and mitoROS in lymph muscle cells (LMCs), resulting in the loss of LV contractions and inducing lymphostasis and lymphatic injury. Accordingly, we will explore whether DANT, an FDA-approved RYR blocker, can prevent DOX-induced lymphatic dysfunction. Three aims will use an integration of techniques to explore this hypothesis and will rely on protein and functional analysis of isolated lymph muscle cells and whole LVs, use optical imaging to assess volumetric lymph flow in vivo in response to DOX and RYR blockade, and investigate the utility of DANT as a potential therapeutic in a rat breast tumor model. Aim 1 will quantify the gene and protein expression profiles of RYR subtypes and determine whether DOX activates RYRs to increase cytosolic calcium and mitoROS generation as a mechanism of inhibiting LV contractions. Aim 2 will evaluate if DANT represents a potential therapeutic option to prevent DOX- induced suppression of lymph flow and prevent DOX-induced lymphatic injury. Aim 3 will investigate the effects of DANT on the anticancer activity of DOX in a rat model of breast cancer. Thus, we plan to explore RYRs as new therapeutic targets for DOX-related lymphedema and evaluate whether RYR blockers can be repurposed as anti-lymphedema medications.