磷酸化p62的积累与肝细胞癌中NF-E2相关因子2的激活有关。

Accumulation of phosphorylated p62 is associated with NF-E2-related factor 2 activation in hepatocellular carcinoma.

作者信息

Shimizu Takayuki, Inoue Ken-Ichi, Hachiya Hiroyuki, Shibuya Norisuke, Aoki Taku, Kubota Keiichi

机构信息

Second Department of Surgery, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi, 321-0293, Japan.

Center for Research Support, Dokkyo Medical University, Tochigi, Mibu, Japan.

出版信息

J Hepatobiliary Pancreat Sci. 2016 Aug;23(8):467-71. doi: 10.1002/jhbp.364. Epub 2016 Jul 15.

DOI:10.1002/jhbp.364

PMID:27246794

Abstract

BACKGROUND

Frequent alterations are observed in glucose metabolism in hepatocellular carcinoma (HCC). Activation of various enzymes, including ones involved in the pentose phosphate pathway, by NF-E2-related factor 2 (NRF2), controls redox homeostasis in HCC. However, the mechanisms mediating NRF2 activation remain unclear. Here, we aimed to investigate the correlation between NRF2, Kelch-like ECH-associated protein 1 (KEAP1) syntheses and p62 phosphorylation in HCC.

METHODS

Biospecimens were collected from 30 patients with HCC. Protein samples were prepared through subcellular localization. Protein synthesis and phosphorylation were measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. Statistical correlations among immunoblotting data and clinical features were analyzed using SPSS.

RESULTS

Compared to non-tumor counterpart, phosphorylated p62 was accumulated in HCC (12/30; 40% of patients). Nuclear localization of NRF2 was frequently augmented in HCC (19/30; 63.3%). Statistically, p62 phosphorylation was associated with augmented activation of NRF2 (P = 0.001). Accumulation of p62 per se was moderately associated with NRF2 activation (P = 0.132). Loss of KEAP1 protein, on the other hand, poorly correlated with NRF2 activation (P = 1.000).

CONCLUSION

In Japanese HCC, NRF2 activation is associated with phosphorylation of p62, but not with KEAP1 status.

摘要

背景

肝细胞癌（HCC）中常观察到葡萄糖代谢的频繁改变。核因子E2相关因子2（NRF2）激活包括参与磷酸戊糖途径的各种酶，控制HCC中的氧化还原稳态。然而，介导NRF2激活的机制仍不清楚。在此，我们旨在研究HCC中NRF2、 Kelch样ECH相关蛋白1（KEAP1）合成与p62磷酸化之间的相关性。

方法

收集30例HCC患者的生物标本。通过亚细胞定位制备蛋白质样品。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳和免疫印迹法测量蛋白质合成和磷酸化。使用SPSS分析免疫印迹数据与临床特征之间的统计相关性。

结果

与非肿瘤对应物相比，磷酸化p62在HCC中积累（12/30；40%的患者）。NRF2的核定位在HCC中经常增加（19/30；63.3%）。统计学上，p62磷酸化与NRF2激活增加相关（P = 0.001）。p62本身的积累与NRF2激活中度相关（P = 0.132）。另一方面，KEAP1蛋白的缺失与NRF2激活相关性较差（P = 1.000）。