Viticchiè Guiditta, Agostini Massimiliano, Lena Anna Maria, Mancini Mara, Zhou Huiqing, Zolla Lello, Dinsdale David, Saintigny Gaelle, Melino Gerry, Candi Eleonora
Department of Experimental Medicine and Surgery, University of "Tor Vergata", 00133 Rome, Italy;
Department of Experimental Medicine and Surgery, University of "Tor Vergata", 00133 Rome, Italy; Toxicology Unit, Medical Research Council, Leicester LE1 9HN, United Kingdom;
Proc Natl Acad Sci U S A. 2015 Sep 15;112(37):11577-82. doi: 10.1073/pnas.1508871112. Epub 2015 Aug 31.
Short p63 isoform, ΔNp63, is crucial for epidermis formation, and it plays a pivotal role in controlling the turnover of basal keratinocytes by regulating the expression of a subset of genes involved in cell cycle and cell adhesion programs. The glycolytic enzyme hexokinase 2 (HK2) represents the first step of glucose utilization in cells. The family of HKs has four isoforms that differ mainly in their tissue and subcellular distribution. The preferential mitochondrial localization of HK2 at voltage-dependent anion channels provides access to ATP generated by oxidative phosphorylation and generates an ADP/ATP recycling mechanism to maintain high respiration rates and low electron leak. Here, we report that ΔNp63 depletion in human keratinocytes impairs mitochondrial basal respiration and increases mitochondrial membrane polarization and intracellular reactive oxygen species. We show ΔNp63-dependent regulation of HK2 expression, and we use ChIP, validated by p63-Chip sequencing genomewide profiling analysis, and luciferase assays to demonstrate the presence of one p63-specific responsive element within the 15th intronic region of the HK2 gene, providing evidence of a direct interaction. Our data support the notion of ΔNp63 as a master regulator in epithelial cells of a combined subset of molecular mechanisms, including cellular energy metabolism and respiration. The ΔNp63-HK2 axis is also present in epithelial cancer cells, suggesting that ΔNp63 could participate in cancer metabolic reprogramming.
短型p63异构体ΔNp63对表皮形成至关重要，它通过调节参与细胞周期和细胞黏附程序的一组基因的表达，在控制基底角质形成细胞的更新中起关键作用。糖酵解酶己糖激酶2（HK2）是细胞中葡萄糖利用的第一步。己糖激酶家族有四种异构体，主要在组织和亚细胞分布上有所不同。HK2在电压依赖性阴离子通道处优先定位于线粒体，可获取氧化磷酸化产生的ATP，并产生ADP/ATP循环机制以维持高呼吸速率和低电子泄漏。在此，我们报告人类角质形成细胞中ΔNp63的缺失会损害线粒体基础呼吸，增加线粒体膜极化和细胞内活性氧。我们展示了ΔNp63对HK2表达的依赖性调节，并使用经全基因组p63芯片测序分析验证的染色质免疫沉淀（ChIP）和荧光素酶测定，来证明HK2基因第15个内含子区域内存在一个p63特异性反应元件，提供了直接相互作用的证据。我们的数据支持ΔNp63作为上皮细胞中包括细胞能量代谢和呼吸在内的一组分子机制的主要调节因子的观点。ΔNp63-HK2轴也存在于上皮癌细胞中，这表明ΔNp63可能参与癌症代谢重编程。
