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，导致预后不良， 乳腺癌患者。与组织稳态对发育和修复至关重要的急性缺氧相反， 在实体瘤中观察到的慢性缺氧通过过度的血管内皮细胞刺激非生产性血管生成 生长因子的表达导致功能障碍的血管，使缺氧和酸性细胞外 pH值;限制化疗和放疗等治疗方式有效灌注的因素， 促进肿瘤的侵袭性。巨噬细胞密切参与调节非生产性血管生成 通过分泌支持这种活性的可溶性因子。在母基金中，我们推进了电子顺磁 基于EPR的技术用于动物体内实时肿瘤微环境（TME）分析 癌症模型。使用这些方法，我们发现巨噬细胞缺氧诱导转录因子（HIF）- 1α和HIF-2α通过结构和功能调节TME参数，如氧和pHe， 决定多西他赛疗效的血管功能改变。我们发现，HIF-1α增加表达， 内皮酪氨酸激酶（TIE 2）受体的巨噬细胞称为TIE 2表达巨噬细胞（TEM） 以前报告为“促血管生成”，但现在通过血管失调更好地定义为“促缺氧” 导致灌注不良。更新的总体目标是研究巨噬细胞的位置和功能 这使缺氧的TME持续存在，对治疗方式的灌注有害。为了实现这一中心目标， 目的，我们提出这些具体目标：（SA 1）：优化磁共振成像模式， 局部肿瘤组织参数的体内多功能映射。顺磁探针的研究进展 成像技术，如快速扫描EPR成像和Overhauser增强MRI允许映射 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中的位置特异性功能， 在乳腺癌小鼠模型中的酸中毒。我们将在PyMT中对肿瘤起源和缺氧区域进行采样， 使用图像引导活检的乳腺癌模型，以了解TME的双向成形， 巨噬细胞导致血管灌注不良和缺氧。(SA3)：调查招募和组织- 常驻巨噬细胞群体及其各自在促进肿瘤缺氧和 酸中毒决定了化疗的有效性我们将追踪荧光骨髓单核细胞到肿瘤 起源，并产生条件性巨噬细胞缺陷乳腺肿瘤小鼠，以系统地确定因果关系 特定巨噬细胞群体的作用。总之，肿瘤缺氧和酸中毒的体内绘图使用 创新的磁共振技术在缺乏特定巨噬细胞群体或缺乏 在乳腺癌小鼠模型中，低氧调节的巨噬细胞功能可能为乳腺癌的发生提供新的见解。 在某些实施方案中，TME轴抑制了巨噬细胞/TME轴，其抑制临床相关抗癌疗法的功效。

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.