Image-Based Phenotyping of Hepatocellular Carcinoma Cell Survival Under Ischemic Stress: Toward Metabolic Imaging of Cancer Dormancy Using Hyperpolarized Carbon-13 Technology

 描述(申请人提供)：已建立的评估实体肿瘤治疗反应的指南是基于传统的成像指标，如肿瘤大小和血管，旨在促进对系统管理的化疗药物的反应的统一评估，这些化疗药物以良好灌流的微环境中的增殖细胞为靶点。肿瘤复发的一种新的成像表型表明，在完全的放射学反应之后，可能伴随着不同的潜伏期，在灌流不良的微环境中没有明显的生长。这种成像表型突出了癌细胞调整其生长计划以适应其微环境并影响肿瘤休眠的能力。这种改变的肿瘤代谢的功能测量的发展对于有效的临床前和临床反应成像是至关重要的。肝细胞癌的肝动脉化疗栓塞术(TACE)为这一影像缺陷提供了令人信服的临床证据。TACE利用肝癌的血管生物学来剥夺肿瘤的营养，导致肿瘤坏死；然而，在接受治疗的大型病变中，只有44%的病变在病理上表现出广泛的坏死，这突显了肝癌细胞对营养缺乏的适应性反应。这种适应性反应反映在组织病理学上邻近坏死区的活肿瘤细胞的存在，并与在后续成像中经常发现的一段潜伏期后的快速复发相一致。因此，TACE为确定癌细胞动员以生存严重缺血的机制提供了一个有用的模型。在初步研究中，我们已经证明了TACE样的严重缺血诱导存活细胞静止，这些细胞激活代谢应激反应(MSR)，包括低氧诱导因子、未折叠蛋白反应和自噬，从而重新编程代谢，使其能够在缺血条件下存活。动态超极化~(13)C核磁共振波谱和光谱成像(DNP-13C-NMRS)的最新进展在肝细胞疾病代谢研究中取得了可喜的成果。这项技术代表着一种独特的资源，可以将我们对MSR的理解进展转化为一种非侵入性的、临床适用的成像范例，以识别在缺血中存活的休眠癌细胞。利用靶向代谢组学、蛋白质组学和表观遗传学对肝癌细胞进行靶向代谢组学、蛋白质组学和表观遗传学分析，以开发基于DNP-13C-NMRS的成像方法，研究TACE后在代谢应激下持续存活而没有增殖的常规成像表型。这项应用的主要目标是：a)表征营养微环境以及MSR诱导的缺血应激存活细胞的表观遗传学和蛋白质组变化；b)开发基于DNP-13C-NMRS的代谢成像方法，以实现对体外缺血应激存活细胞的非侵入性检测；以及c)将该方法转化为体内动脉栓塞术中存活细胞的特征。

 DESCRIPTION (provided by applicant): Established guidelines for assessing response of solid tumors to therapy are based on conventional imaging indices, such as tumor size and vascularity, and were intended to facilitate a uniform assessment of response to systemically administered chemotherapeutics that target proliferating cells in a well-perfused microenvironment. An emerging imaging phenotype of tumor recurrence indicates that a complete radiographic response may be followed by variable periods of latency without perceptible growth in poorly perfused microenvironments. This imaging phenotype highlights the capability of cancer cells to adapt their growth program to their microenvironment and effect tumor dormancy. The development of functional measures of this altered tumor metabolism is critical to effective preclinical and clinical imaging of response. Trans-arterial chemoembolization (TACE) for the treatment of hepatocellular carcinoma (HCC) provides a compelling clinical correlate to this imaging deficiency. TACE exploits the vascular biology of HCC to deprive tumors of nutrients, leading to necrosis; however, only 44% of large treated lesions demonstrate extensive necrosis on pathology, underscoring the adaptive response of HCC cells to nutrient deprivation. This adaptive response is reflected by the presence of viable tumor cells adjacent to regions of necrosis on histopathology, and is consistent with the rapid recurrence following a period of latency that is often discovered on follow-up imaging. Thus, TACE provides a useful model for identifying the mechanisms mobilized by cancer cells to survive severe ischemia. In preliminary studies, we have demonstrated that TACE-like severe ischemia induces quiescence in surviving cells and that these cells activate a metabolic stress response (MSR) including hypoxia-inducible factors, the unfolded protein response and autophagy, which reprogram metabolism to enable survival under ischemic conditions. The recent development of Dynamic Hyperpolarized Carbon-13 Nuclear Magnetic Resonance spectroscopy and spectroscopic imaging (DNP-13C-NMRS) has yielded promising results in studies of metabolism in hepatocellular disease. This technology represents a unique resource to translate advances in our understanding of the MSR into a non-invasive, clinically applicable imaging paradigm to identify dormant cancer cells surviving ischemia. The conventional post-TACE imaging phenotype of sustained survival without proliferation under metabolic stress will be examined using targeted metabolomics, proteomic and epigenetic profiling of HCC cells to develop a DNP-13C-NMRS based imaging approach. The primary objectives of this application are to: a) characterize the nutrient microenvironment as well as the epigenetic and proteomic alterations underlying MSR-induced metabolic adaptation in cells surviving ischemic stress, b) develop a DNP- 13C-NMRS based metabolic imaging approach to enable the non-invasive detection of cells surviving ischemic stress in vitro, and c) translate this approach to characterize cells surviving trans-arterial embolization in vivo.