Hu Bo, Xu Yang, Li Yuan-Cheng, Huang Jun-Feng, Cheng Jian-Wen, Guo Wei, Yin Yue, Gao Yang, Wang Peng-Xiang, Wu Sui-Yi, Zhou Jian, Fan Jia, Yang Xin-Rong
Department of Liver Surgery & Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, P.R. China.
Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai, P. R. China.
Clin Transl Med. 2020 Dec;10(8):e233. doi: 10.1002/ctm2.233.
CD13 is a new marker for liver cancer stem cells (CSCs) that contributes to sorafenib resistance in hepatocellular carcinoma (HCC). However, the underlying mechanism of CD13 in HCC sorafenib resistance remains enigmatic.
The expression of CD13 in HCC cell lines and tissues was assayed by RT-PCR, western-blot, and immunohistochemistry staining. Athymic BALB/c nu/nu mice model was used to study the in vivo functions of CD13. Clinical significance of CD13 was evaluated by Kaplan-Meier methods. Cellular proliferation rate was evaluated by cell counting kit-8 cell proliferation assay and colony formation assay. Tunel assay was used to detect cell death ratio. Transwell assay was used to evaluate the motility of cells. Immunoprecipitation (IP), liquid chromatography-mass spectrometry (LC-MS)/MS, and co-IP were applied to investigate potential protein interactions of CD13.
In this research, we found that CD13 expression was higher in metastatic HCC samples, and its overexpression was predicted worse prognosis for patients after surgical resection. Functionally, CD13 promoted HCC proliferation, invasion, cell cycle progression as well as sorafenib resistance. Mechanistically, CD13 interacted with histone deacetylase5 (HDAC5) to promote its protein stability, thus resulting in HDAC5-mediated lysine-specific demethylase 1 (LSD1) deacetylation and protein stabilization. Consequently, LSD1 decreased the NF-κB catalytic unit p65 methylation that led to p65 protein stability. A CD13 inhibitor ubenimex in combination with sorafenib, suppressed the tumor growth and attenuated the resistance of HCC cells toward sorafenib in patient-derived xenograft models.
CD13 promotes HCC progression and induces sorafenib resistance, mainly via interacting with HDAC5 to prevent the degradation of p65 and activate NF-kB signaling pathway. CD13 is a prognostic indicator for HCC patients underwent curative resection as well as a predictor of response to treatment with sorafenib. Our study establishes the new therapeutic potential of targeting CD13-HDAC5-LSD1-NF-κB in HCC.
CD13是肝癌干细胞（CSCs）的一种新标志物，其在肝细胞癌（HCC）中导致对索拉非尼耐药。然而，CD13在HCC索拉非尼耐药中的潜在机制仍不清楚。
采用RT-PCR、蛋白质免疫印迹法和免疫组织化学染色检测HCC细胞系和组织中CD13的表达。利用无胸腺BALB/c nu/nu小鼠模型研究CD13的体内功能。采用Kaplan-Meier方法评估CD13的临床意义。通过细胞计数试剂盒-8细胞增殖试验和集落形成试验评估细胞增殖率。采用Tunel试验检测细胞死亡率。采用Transwell试验评估细胞的运动能力。应用免疫沉淀（IP）、液相色谱-质谱联用（LC-MS）/MS和免疫共沉淀研究CD13潜在的蛋白质相互作用。
在本研究中，我们发现转移性HCC样本中CD13表达较高，其过表达预示手术切除后患者预后较差。在功能上，CD13促进HCC增殖、侵袭、细胞周期进程以及对索拉非尼的耐药。机制上，CD13与组蛋白去乙酰化酶5（HDAC5）相互作用以促进其蛋白质稳定性，从而导致HDAC5介导的赖氨酸特异性去甲基化酶1（LSD1）去乙酰化和蛋白质稳定。因此，LSD1降低了NF-κB催化亚基p65的甲基化，导致p65蛋白质稳定。在患者来源的异种移植模型中，CD13抑制剂乌苯美司与索拉非尼联合使用可抑制肿瘤生长并减弱HCC细胞对索拉非尼的耐药性。
CD13主要通过与HDAC5相互作用以防止p65降解并激活NF-κB信号通路，促进HCC进展并诱导索拉非尼耐药。CD13是接受根治性切除的HCC患者的预后指标以及索拉非尼治疗反应的预测指标。我们的研究确立了在HCC中靶向CD13-HDAC5-LSD1-NF-κB的新治疗潜力。
