Profiling iron-regulated metabolic reprogramming for nucleotide biosynthesis in colon tumors

结直肠癌（CRC）是美国癌症相关死亡的第三大原因。了解 CRC发展的机制对于改善治疗至关重要。增加小鼠和 与结肠肿瘤发生的增加有关。然而，铁的确切机制 对结肠癌发生的作用尚不清楚。正常人和癌症之间的代谢差异 细胞正在被询问以发现潜在的新治疗方法。许多肿瘤细胞表现出 增加葡萄糖消耗、谷氨酰胺代谢和核苷酸合成。这项提案将考验 铁驱动的细胞代谢重编程促进DNA合成和结肠癌的中心假设 肿瘤发生这一假设是基于：1）铁补充增加，而螯合铁， 去铁胺（DFO）抑制患者来源的CRC类结肠的生长和细胞增殖; 2）治疗小鼠 高铁饮食增加结肠癌的发生率，而低铁饮食减少结肠癌的发生率和进展; 3)代谢组学分析表明，过量的铁影响葡萄糖刺激的核苷酸合成， 促进低氧非依赖性"Warburg样效应"并在类结肠中促进戊糖磷酸途径; 4） 通过DFO限制铁导致谷氨酰胺积累和核苷酸生物合成中代谢物的减少 结肠中的通路。根据这些观察，该提案将测试以下三个具体目标： 确定过量铁影响CRC中葡萄糖刺激的DNA生物合成的机制; 2）研究 铁限制对CRC中谷氨酰胺依赖性核苷酸合成的影响; 3）表征 DNA聚合酶在铁调节的核苷酸代谢和CRC中的作用我们将利用高度临床相关的CRC 患者来源的类结肠培养、代谢组学分析和各种动物模型。完成上述任务 目的将为肿瘤细胞如何适应铁信号合成提供精确的分子机制 促进肿瘤增殖的核苷酸。这些研究将填补我们对铁如何调节 CRC生长和进展。

Colorectal cancer (CRC) is the third leading cause of cancer-related death in US. Understanding the mechanisms of CRC development is essential to improve treatment. Increased tissue iron in both mice and humans is associated with increased colon tumorigenesis. However, the precise mechanisms for how iron contributes to colon carcinogenesis are still unclear. The metabolic differences between normal and cancer cells are being interrogated to uncover potential new therapeutic approaches. Many tumor cells exhibit increased glucose consumption, glutamine metabolism and nucleotide synthesis. This proposal will test the central hypothesis that iron-driven cellular metabolic reprograming promotes DNA synthesis and colon tumorigenesis. This hypothesis is based on: 1) iron supplement increases, whereas chelation of iron by deferoxamine (DFO) inhibits the growth and cell proliferation of patient-derived CRC colonoids; 2) treating mice with high-iron diet increases, while low-iron diet decreases colon tumor multiplicity, incidence and progression; 3) metabolomics analysis reveals that excess iron impacts glucose-stimulated nucleotide synthesis by promoting hypoxia-independent “Warburg-like effect” and fueling pentose phosphate pathway in colonoids; 4) iron restriction by DFO leads to glutamine accumulation and reduction of metabolites in nucleotide biosynthesis pathways in colonoids. Based on these observations, the proposal will test the following three Specific Aims: 1) Define the mechanism by which excess iron affects glucose-stimulated DNA biosynthesis in CRC; 2) Study the impact of iron restriction on glutamine-dependent nucleotide synthesis in CRC; 3) Characterize the role of a DNA polymerase in iron-regulated nucleotide metabolism and CRC. We will utilize highly clinic-relevant CRC patient-derived colonoid culture, metabolomics analysis, and various animal models. Accomplishing the above Aims will provide precise molecular mechanisms for how tumor cells are adapted to iron signal to synthesize nucleotides for facilitating tumor proliferation. These studies will fill our knowledge gap of how iron regulates CRC growth and progression.