MKP-1 Effects on HIF-1alpha and Glycolytic Metabolism in Glioblastoma multiforme

描述（由申请人提供）：肿瘤细胞表型的两个主要特征是高应激条件下向糖酵解呼吸和凋亡抵抗的生物能量转变。这些通路共同的一个关键调控节点是缺氧诱导因子-1 （HIF-1）。多形性胶质母细胞瘤（GBM）微环境中的局部缺氧和相关的体细胞突变聚集在一起，刺激HIF-1活性，进一步促进肿瘤进展。在永生化的GBM细胞系和原发切除的肿瘤裂解物中，我们发现MAP激酶磷酸酶（MKP-1）的表达减少与HIF-1靶点单羧酸转运蛋白4 （MCT4）的诱导相关，MCT4是糖酵解肿瘤稳态的关键乳酸转运蛋白。通过基因调控U87和U251肿瘤细胞系中p53和MKP-1的水平，我们试图确定MKP-1和MCT4在GBM中的作用。MKP-1对糖酵解代谢的影响将通过转录分析来评估，以确定对参与代谢和生存的HIF-1靶点的影响。因此，代谢物分析将确定该信号通路的功能作用。然后，我们通过临床GBM样本中MKP-1和MCT4的Western和免疫组织化学联合分析，建立了这一途径的相关性。总的来说，这些研究试图将MKP-1和MCT4作为肿瘤分级的临床相关标志物，并研究它们在这种毁灭性疾病中的潜在治疗作用。

DESCRIPTION (provided by applicant): Two cardinal features of the tumor cell phenotype are a bioenergetic shift toward glycolytic respiration and apoptotic resistance under high stress conditions. A key regulatory node common to each of these pathways is the hypoxia inducible factor-1¿ (HIF-1¿). Regional hypoxia within the microenvironment of glioblastoma multiforme (GBM) and related somatic mutations converge to stimulate HIF-1¿ activity further enhancing tumor progression. In both immortalized GBM lines and primary resected tumor lysates we find that reduced expression of the MAP kinase phosphatase (MKP-1) correlates with the induction of the HIF-1¿ target mono- carboxylate transporter 4 (MCT4), a lactate transporter critical to homeostasis of glycolytic tumors. By genetically manipulating levels of p53 and MKP-1 in the U87 and U251 tumor lines, we seek to establish a role for MKP-1 and MCT4 in GBM. The effects of MKP-1 on glycolytic metabolism will be assessed using transcriptional analyses to identify effects on HIF-1¿ targets involved in metabolism and survival. Consequently, metabolite analyses will establish the functional role of this signaling pathway. We then establish the relevance of this pathway through the combined Western and immunohistochemical analysis of MKP-1 and MCT4 in clinical GBM samples. In aggregate these studies seek to implicate MKP-1 and MCT4 as clinically relevant markers tumor grade, and to investigate their potential role therapeutic targets for this devastating disease.