Chen Xiaowen, Huang Zhenqi, Wu Wei, Xia Ruixiang
Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, People's Republic of China.
Cancer Manag Res. 2020 Jun 22;12:4777-4787. doi: 10.2147/CMAR.S253367. eCollection 2020.
Skp2 is an E3 ubiquitin ligase that plays an important role in modulating tumor progression. The mechanisms underlying Skp2 in the promotion of proliferation and its function in the primary resistance to tyrosine kinase inhibitors (TKIs) in human CML remain to be determined. This study aimed to investigate the function of Skp2 in CML progression as well as its effects on TKI sensitivity.
Expression of Skp2 in leukocytes from patients with CML and normal blood samples was analyzed by qRT-PCR. Cell proliferation was analyzed by EdU incorporation and cell counting assays. Luciferase reporter and chromatin immunoprecipitation assays were used for examination of the effects of CREB on Skp2 expression. The apoptosis in vitro of K562 cells was analyzed by MTT and caspase 3/7 activity assays.
The present study demonstrates that Skp2 was expressed at a higher level in patients with CML compared with healthy donors, and the elevated expression of Skp2 is critical for CML cell proliferation. Mechanistically, Skp2 was transcriptionally upregulated by CREB responsive to the PI3K/Akt signaling pathway. Furthermore, inhibition of Skp2 expression by shRNAs or blocking the PI3K/Akt/CREB pathway greatly enhances the sensitivity of CML cells to Imatinib treatment.
We conclude that the PI3K/Akt/CREB axis regulates the sensitivity of K562 cells to Imatinib via mediating Skp2 expression. The present study revealed an unknown role of Skp2 in CML progression and provided new aspects on the Skp2-modulated TKI sensitivity in CML, contributing to the development of potential therapeutic anticancer drugs.
Skp2是一种E3泛素连接酶，在调节肿瘤进展中起重要作用。Skp2促进增殖的潜在机制及其在人类慢性粒细胞白血病（CML）对酪氨酸激酶抑制剂（TKIs）原发性耐药中的作用仍有待确定。本研究旨在探讨Skp2在CML进展中的作用及其对TKI敏感性的影响。
通过qRT-PCR分析CML患者白细胞和正常血液样本中Skp2的表达。通过EdU掺入和细胞计数分析检测细胞增殖。使用荧光素酶报告基因和染色质免疫沉淀分析检测CREB对Skp2表达的影响。通过MTT和caspase 3/7活性分析检测K562细胞的体外凋亡。
本研究表明，与健康供体相比，CML患者中Skp2的表达水平更高，Skp2的高表达对CML细胞增殖至关重要。机制上，Skp2通过对PI3K/Akt信号通路有反应的CREB转录上调。此外，shRNAs抑制Skp2表达或阻断PI3K/Akt/CREB通路可大大增强CML细胞对伊马替尼治疗的敏感性。
我们得出结论，PI3K/Akt/CREB轴通过介导Skp2表达来调节K562细胞对伊马替尼的敏感性。本研究揭示了Skp2在CML进展中的未知作用，并为Skp2调节的CML中TKI敏感性提供了新的方面，有助于开发潜在的抗癌治疗药物。
