MACC1调控葡萄糖代谢抑制胃癌细胞衰老的机制研究

It is known that celluar senescence can be induced by metabolic stress, while cancer cells usually resist against senescence by adopting a unique metabolic manner (i.e. Warburg effect). Recently, more and more oncogenes are proved to take part in cancer cell metabolism and senescence regulation. Metastasis-associated in colon cancer-1 (MACC1) is a newly identified oncogene, and we first reported that MACC1 regulated the cell-cycle and ensured the viability of gastric cancer (GC) cells. Currently, the relation between MACC1 and tumor metabolism as well as cancer senescence resistance remains unknown. Our latest experiments on GC discovered that metabolic stress increased MACC1 expression, and that MACC1 upregulation enhanced glucose metabolism and suppressed GC cell senescence. These suggested that MACC1 might play a significant role in regulating GC glucose metabolism and senescence-resistance. Accordingly, we hypothesize that MACC1 compensatory upregulation helps GC cells resist against metabolic stress-induced senescence by promoting Warburg effect. Current project will be carried out by means of metabolic status assay, cellular functional experiments, and molecular biological experiments at clinical, animal, cellular, and molecular levels. The results of this study will clarify the relationship among MACC1, Warburg effect and senescence resistance.

已知代谢应激能诱发机体细胞衰老，而肿瘤细胞却能以独特的葡萄糖代谢方式（Warburg效应）抵抗衰老。近年，许多癌基因被证实参与肿瘤细胞代谢和衰老调控。结肠癌转移相关基因-1（MACC1）是新近发现的癌基因，我们首次报道了MACC1能影响胃癌的细胞周期和活力，并影响患者预后。但尚不知：MACC1与肿瘤代谢、衰老的关系是什么？我们近期发现代谢应激能够上调胃癌细胞MACC1表达，MACC1过表达能增强葡萄糖代谢并抑制细胞衰老，提示MACC1可能在抵抗胃癌细胞衰老和代谢调控中发挥重要作用。因此我们假设：代谢应激代偿性地使胃癌细胞MACC1升高，MACC1通过Warburg效应抵抗其衰老。本项目拟借助代谢状态检测、细胞功能实验及分子生物学实验等手段，从临床、动物、细胞和分子四个层次展开研究，阐明MACC1与胃癌细胞代谢调控及抗衰老调控的关系。

1.背景：.肿瘤微环境中，营养缺乏导致的代谢应激现象普遍存在，肿瘤细胞对其抵抗进而适应的机制仍未阐明。前期研究发现，代谢应激可激活结直肠癌相关转移基因MACC1的表达，抑制细胞凋亡，但是其具体机制尚未阐明。我们的预实验发现：MACC1存在一个反义Lnc RNA MACC1-AS1，本项目研究MACC1-AS1抵抗胃癌细胞代谢应激的机制，探索其与MACC1的调控关系。.2. 研究内容及研究结果：（1）MACC1-AS1在胃癌组织的表达情况及与临床预后的关系：123例胃癌标本中（其中TNM I-III期85例，TNM IV期38例），MACC1-AS1不表达8例（占6.5%），低表达64例（占52.0%），高表达51例（占41.5%）； 癌组织MACC1-AS1的表达高于癌旁组织；MACC1-AS1高表达患者的OS和PFS较MACC1-AS1低表达患者明显缩短；TCGA数据库及连续切片染色显示MACC1-AS1与MACC1的表达呈正相关关系；动物模型证实MACC1-AS1可促进胃癌的生长和转移，对瘤组织行免疫组化显示其增值指标Ki 67增加，糖酵解指标HK2，GLUT1的表达增加，而氧化损伤标志物8-OHdG减少。（2）代谢应激与MACC1-AS1的关系。结果：通过无糖培养，H2O2及葡萄糖类似物2-DG模拟代谢应激，发现代谢应激通过活性氧生成促进MACC1-AS1表达，这一过程可被活性氧清除剂所逆转；过表达MACC1-AS1后抑胃癌细胞代谢应激条件下的凋亡，并促进其增值；MACC1-AS1通过促进GLUT1，HK2和LDH的表达促进糖酵解过程，葡萄糖吸收率增加，糖酵解产物ATP，乳酸的生成增加；MACC1-AS1促进NADPH，GSH的生成，抑制活性氧，抵抗代谢应激；（3）MACC1-AS1对MACC1的调控与代谢应激的关系：mRNA 稳定性实验证实MACC1-AS1 促进MACC1 mRNA的稳定性促进MACC1的表达，这一过程依赖于AMPK/Lin 28通路的激活；最终证实：MACC1-AS1通过调控MACC1 mRNA稳定性促进MACC1表达，抵抗代谢应激。.3. 研究意义：代谢应激在肿瘤微环境中普遍存在，抗代谢疗法一直是肿瘤治疗的研究方向。 我们发现MACC1-AS1 / MACC1轴在代谢调控中的重要作用为抗代谢治疗提供了新的策略。