Kachel Paul, Trojanowicz Bogusz, Sekulla Carsten, Prenzel Hanna, Dralle Henning, Hoang-Vu Cuong
Department of General, Visceral and Vascular Surgery, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Halle/Saale, Germany.
Department of Internal Medicine II, Faculty of Medicine, Martin-Luther-University of Halle-Wittenberg, Halle/Saale, Germany.
BMC Cancer. 2015 Mar 18;15:140. doi: 10.1186/s12885-015-1135-y.
Lactate dehydrogenase A (LDHA) and Pyruvate Kinase M2 (PKM2) are important enzymes of glycolysis. Both of them can be phosphorylated and therefore regulated by Fibroblast growth factor receptor 1 (FGFR1). While phosphorylation of LDHA at tyrosine10 leads to tetramerization and activation, phosphorylation of PKM2 at tyrosine105 promotes dimerization and inactivation. Dimeric PKM2 is found in the nucleus and regulates gene transcription. Up-regulation and phosphorylation of LDHA and PKM2 contribute to faster proliferation under hypoxic conditions and promote the Warburg effect.
Using western blot and SYBR Green Real time PCR we investigated 77 thyroid tissues including 19 goiter tissues, 11 follicular adenomas, 16 follicular carcinomas, 15 papillary thyroid carcinomas, and 16 undifferentiated thyroid carcinomas for total expression of PKM2, LDHA and FGFR1. Additionally, phosphorylation status of PKM2 and LDHA was analysed. Inhibition of FGFR was performed on FTC133 cells with SU-5402 and Dovitinib.
All examined thyroid cancer subtypes overexpressed PKM2 as compared to goiter. LDHA was overexpressed in follicular and papillary thyroid cancer as compared to goiter. Elevated phosphorylation of LDHA and PKM2 was detectable in all analysed cancer subtypes. The highest relative phosphorylation levels of PKM2 and LDHA compared to overall expression were found in undifferentiated thyroid cancer. Inhibition of FGFR led to significantly decreased phosphorylation levels of PKM2 and LDHA.
Our data shows that overexpression and increased phosphorylation of PKM2 and LHDA is a common finding in thyroid malignancies. Phospho-PKM2 and Phospho-LDHA could be valuable tumour markers for thyroglobulin negative thyroid cancer.
乳酸脱氢酶A（LDHA）和丙酮酸激酶M2（PKM2）是糖酵解的重要酶。它们均可被磷酸化，因此受成纤维细胞生长因子受体1（FGFR1）调控。酪氨酸10位点的LDHA磷酸化导致四聚化并激活，而酪氨酸105位点的PKM2磷酸化促进二聚化并使其失活。二聚体PKM2存在于细胞核中并调节基因转录。LDHA和PKM2的上调及磷酸化有助于在缺氧条件下更快地增殖，并促进瓦伯格效应。
我们使用蛋白质免疫印迹法和SYBR Green实时荧光定量PCR，研究了77例甲状腺组织，包括19例甲状腺肿组织、11例滤泡性腺瘤、16例滤泡癌、15例乳头状甲状腺癌和16例未分化甲状腺癌中PKM2、LDHA和FGFR1的总表达情况。此外，还分析了PKM2和LDHA的磷酸化状态。使用SU-5402和多韦替尼对FTC133细胞进行FGFR抑制。
与甲状腺肿相比，所有检测的甲状腺癌亚型均过表达PKM2。与甲状腺肿相比，滤泡状和乳头状甲状腺癌中LDHA过表达。在所有分析的癌症亚型中均检测到LDHA和PKM2的磷酸化水平升高。与总体表达相比，未分化甲状腺癌中PKM2和LDHA的相对磷酸化水平最高。FGFR抑制导致PKM2和LDHA的磷酸化水平显著降低。
我们的数据表明，PKM2和LHDA的过表达及磷酸化增加在甲状腺恶性肿瘤中是常见现象。磷酸化PKM2和磷酸化LDHA可能是甲状腺球蛋白阴性甲状腺癌的有价值的肿瘤标志物。
