SPP1靶向miR-34/p53信号网络调控胃癌细胞Warburg效应的作用和机制研究

SPP1 (Osteopontin) is a multifunctional matrix protein secreted by a variety of cells. High expression of SPP1 can promote the proliferation and metastasis of tumor cells. But its regulatory role in Warburg effect and its molecular mechanism has not been illustrated. It was found that high expression of SPP1 augmented the glucose uptake of tumor cells and regulated the activity of Akt, suggesting that SPP1 may regulate Warburg Effect in gastric cancer. In our previous study, we found the phenomenon of high expression of SPP1 in patients with gastric cancer, targeted regulation of SPP1 by miR-34, and potentially negative interaction between SPP1 and p53. The aim of the present study is to investigate whether different energy metabolic conditions affect SPP1 expression and whether different expression levels of SPP1 affect energy metabolism, confirming the role of SPP1 in regulating the Warburg effect in gastric cancer; to explore the mechanism of up-regulated SPP1 from the epigenetics perspective and to analyze the influence of different expression levels of SPP1 on miR-34/p53 signal activities, understanding the mechanisms of SPP1 regulating Warburg Effect in gastric cancer; to validate the correlations between SPP1 and its regulatory signaling molecules and Warburg effect-related biomarkers in clinical samples, and to analyze the clinical significance of SPP1 in combination with other molecules in gastric cancer. Elucidating the regulatory role of SPP1 in Warburg effect and its molecular mechanism can provide experimental evidence and a novel view for target therapy of gastric cancer.

作为一个可为多种细胞所分泌的多功能基质蛋白，SPP1基因（编码骨桥蛋白）高表达可促肿瘤增殖和转移，但其调节肿瘤Warburg效应的作用和机制尚无报道。研究报道SPP1高表达能增加肿瘤细胞葡萄糖的摄取并激活Akt活性。我们前期发现SPP1高表达于胃癌患者的血清和肿瘤组织，并且SPP1可受miR-34（microRNA-34）靶向调控同时可能与能量代谢相关的p53存在调控关系。本项目拟进一步观察不同代谢条件对SPP1基因表达以及SPP1不同表达水平对能量代谢的影响，以明确SPP1基因对胃癌Warburg效应的调控作用；鉴定SPP1与miR-34/p53信号网络的调控关系，以明确SPP1调控胃癌Warburg效应的机制；在临床标本中验证SPP1联合miR-34/p53信号网络相关分子在胃癌中的临床意义。对SPP1调控胃癌Warburg效应的作用和机制的阐明可为靶向能量代谢的胃癌诊治提供依据。

SPP1作为一个可为多种细胞所分泌的多功能基质蛋白。本研究证实SPP1基因中的SPP1a和SPP1b转录本可促肿瘤增殖和转移，并且通过检测Warburg系列相关表达指标，证实其可以促进肿瘤的糖酵解途径。在肿瘤组织和血清中，从蛋白和mRNA水平均发现SPP1高表达于胃癌患者的血清和肿瘤组织，该表达的差异在正常和肿瘤中区分度较高，曲线下面积达0.78-0.81。通过瞬转和稳转建立过表达的细胞株，证实SPP1可受miR-34b负性调控,而TP53可同时被miR-34b和miR-34c负性调控，然而我们并没有发现SPP1和TP53存在直接调控关系，提示 SPP1和p53表达的正相关可能与miR-34b的间接调控有关。我们进一步从基因水平、病毒感染、细菌感染探索胃癌的发病机理。在基因水平分析SPP1基因变异与胃癌的发病关系，发现携带SPP1 rs4754的个体胃癌发病风险是非携带者的1.75-1.95倍，SPP1 rs4754 和SPARC rs1054204、rs3210714、rs3549存在交互作用，研究成果已经发表在《Gene》，影响因子2.638。寻找可能影响胃癌炎症反应的外在因素。观察胃癌组织EBV感染与幽门螺杆菌感染可能负相关，与胃功能指标（PGI， PGI/II）正相关，研究成果已经发表在《Virus Research》，影响因子2.736。通过对2017年10月到2017年9月就诊于我院的胃癌进行EBV感染分析，发现EBV相关胃癌的预后优于EBV非感染性胃癌。在EBV相关胃癌中，EBV DNA load水平升高可提示胃癌复发，可作为EBV相关胃癌病情动态观察的生物标志物。研究成果发表在《International Journal of Cancer》，影响因子4.982。上述研究成果可能在将来胃癌的临床诊断和治疗方面作为参考依据。