In vivo monitoring of tumor microenvironment regulation for macrophages

缺氧和巨噬细胞驱动肿瘤侵袭性和治疗结果导致更差的预后 乳腺癌患者。与急性缺氧相反，在急性缺氧中，组织动态平衡对发育和修复至关重要， 实体瘤中观察到的慢性低氧通过过度的血管内皮细胞刺激非生产性血管生成 生长因子表达导致血管功能障碍，使缺氧和酸性细胞外持续存在 PH值；限制化疗和放射治疗等治疗方式有效灌注的因素以及 促进肿瘤侵袭性。巨噬细胞密切参与调节非生产性血管生成 通过分泌支持这一活性的可溶性因子。在家长的资助中，我们提出了电子顺磁 基于磁共振(EPR)的动物体内肿瘤微环境实时监测技术 癌症模型。使用这些方法，我们展示了巨噬细胞缺氧诱导转录因子(HIF)- 1α和HIF-2α在调节TME参数如氧和苯丙氨酸中具有不同的作用，它们通过结构和 决定多西紫杉醇疗效的血管功能改变。我们发现缺氧诱导因子-1的α增强了表达 巨噬细胞表面内皮细胞酪氨酸激酶受体(TIE2)的表达 以前被报道为“促血管生成”，但现在更好地被血管调节失调定义为“促低氧”。 导致血流灌注不良。更新的总体目标是研究巨噬细胞的位置和功能 这使缺氧性TME持续存在，不利于治疗方式的灌流。要实现这一中心 目的：我们提出这些具体目标：(SA1)：优化磁共振成像方式 局部肿瘤组织参数的体内多功能标测。顺磁探头和顺磁材料的研究进展 快速扫描EPR成像和Overhauser增强MRI等成像技术允许进行映射 缺氧和酸中毒的特定区域及其与肿瘤巨噬细胞局部区域的关系 人口。(SA2)：阐明肿瘤巨噬细胞在调节缺氧和 乳癌小鼠模型中的酸中毒。我们将对PYMT中的肿瘤来源和缺氧区进行采样 应用图像引导活检了解TME和TME双向成形的乳腺癌模型 巨噬细胞导致血管灌流不良和缺氧。(SA3)：调查招募人员和组织-- 常驻巨噬细胞种群及其在肿瘤缺氧和死亡中的作用 决定化疗效果的酸中毒。我们将追踪荧光骨髓单核细胞到肿瘤 来源，并产生条件巨噬细胞缺陷的乳腺肿瘤小鼠系统地确定原因 特定巨噬细胞群的作用。总结，体内标测肿瘤缺氧和酸中毒使用 在缺乏特定巨噬细胞群或缺乏的小鼠中采用创新的磁共振技术 低氧调节的巨噬细胞在乳腺癌小鼠模型中的功能可能为研究 巨噬细胞/TME轴抑制临床相关抗癌治疗的疗效。

Hypoxia and macrophages drive tumor aggressiveness and treatment outcome leading to worse prognosis for breast cancer patients. Contrary to acute hypoxia where tissue homeostasis is vital for development and repair, chronic hypoxia observed in solid tumors stimulate unproductive angiogenesis by excessive vascular endothelial growth factor expression leading to dysfunctional vessels that perpetuate hypoxia and acidic extracellular pH; factors that limit effective perfusion of treatment modalities like chemotherapies and radiotherapies and promote tumor aggressiveness. Macrophages are intimately involved in regulating unproductive angiogenesis thru secretion of soluble factors that support this activity. In the parent grant, we advanced electron paramagnetic resonance (EPR)-based techniques towards in vivo real-time tumor microenvironment (TME) profiling in animal cancer models. Using these approaches, we showed macrophage hypoxia-inducible transcription factors (HIF)- 1α and HIF-2α had disparate roles in regulating TME parameters like oxygen and pHe through structural and functional alterations in vessels that dictated docetaxel efficacy. We showed that HIF-1α augments expression of endothelial tyrosine kinase (TIE2) receptor on macrophages called TIE2-expressing macrophages (TEMs) previously-reported to be “pro-angiogenic”, but now better defined as “pro-hypoxic” by dysregulating vessels leading to poor perfusion. The overall objective of the renewal is to investigate macrophage location and function that perpetuates a hypoxic TME detrimental to perfusion of therapeutic modalities. To achieve this central objective, we propose these specific aims: (SA1): To optimize magnetic resonance imaging modalities for in vivo multifunctional mapping of local tumor tissue parameters. Advances in paramagnetic probes and imaging technologies such as rapid scan EPR imaging and Overhauser-enhanced MRI allow for mapping specific areas of hypoxia and acidosis and characterizing their relationship to tumor macrophage locoregional populations. (SA2): Elucidate tumor macrophage location-specific functions in regulating hypoxia and acidosis in a mouse model of breast cancer. We will sample tumor origin and regions of hypoxia in PyMT breast cancer models using image-guided biopsy to understand the bi-directional shaping of TME and macrophages that contribute to poor vessel perfusion and hypoxia. (SA3): Investigate recruited and tissue- resident macrophage populations and their respective roles in contributing to tumor hypoxia and acidosis that dictate chemotherapy effectiveness. We will track fluorescent bone marrow monocytes to tumor origin, and generate conditional macrophage-deficient breast tumor mice to systematically determine a causal role of specific macrophage populations. Summarizing, in vivo mapping of tumor hypoxia and acidosis using innovative magnetic resonance technology in mice deficient in specific macrophage populations or lacking hypoxia-regulated macrophage functions in a mouse model of breast cancer may provide new insight into a macrophage/TME axis that suppresses the efficacy of clinically-relevant anti-cancer therapies.