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

 描述（由申请人提供）：评估实体瘤对治疗的反应的既定指南基于常规成像指标，如肿瘤大小和血管分布，旨在促进对靶向灌注良好微环境中增殖细胞的全身给药化疗药物的反应进行统一评估。一个新出现的肿瘤复发的影像学表型表明，一个完整的放射学反应可能是由可变的潜伏期，没有明显的增长，在灌注不良的微环境。这种成像表型突出了癌细胞使其生长程序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措施的发展是至关重要的有效的临床前和临床反应成像。经动脉化疗栓塞术（TACE）治疗肝细胞癌（HCC）提供了一个令人信服的临床相关性，这种成像缺陷。TACE利用HCC的血管生物学剥夺肿瘤的营养，导致坏死;然而，只有44%的大型治疗病变在病理学上表现出广泛的坏死，强调了HCC细胞对营养剥夺的适应性反应。这种适应性反应反映在组织病理学上坏死区域附近存在存活的肿瘤细胞，并且与在随访成像中经常发现的潜伏期后的快速复发一致。因此，TACE提供了一个有用的模型，用于识别癌细胞动员的机制，以生存严重缺血。在初步研究中，我们已经证明了TACE样严重缺血诱导存活细胞的静止，并且这些细胞激活代谢应激反应（MSR），包括缺氧诱导因子，未折叠蛋白反应和自噬，其重新编程代谢以使其能够在缺血条件下存活。动态超极化~（13）C核磁共振波谱和波谱成像（DNP-13 C-NMRS）的最新发展在肝细胞疾病的代谢研究中取得了可喜的成果。这项技术代表了一种独特的资源，可以将我们对MSR的理解转化为一种非侵入性的、临床适用的成像模式，以识别在缺血中存活的休眠癌细胞。将使用HCC细胞的靶向代谢组学、蛋白质组学和表观遗传学分析来检查在代谢应激下持续存活而不增殖的常规TACE后成像表型，以开发基于DNP-13 C-NMRS的成像方法。本申请的主要目的是：a）表征营养微环境以及在缺血应激存活的细胞中作为MSR诱导的代谢适应的基础的表观遗传和蛋白质组学改变，B）开发基于DNP-13 C-NMRS的代谢成像方法以使得能够在体外非侵入性检测缺血应激存活的细胞，和c）将该方法转化为表征在体内经动脉栓塞中存活的细胞。

 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.