Su Tianhong, Huang Manling, Liao Junbin, Lin Shuibin, Yu Peng, Yang Jianhua, Cai Yuhong, Zhu Shenghua, Xu Lixia, Peng Zhenwei, Peng Sui, Chen Shuling, Kuang Ming
Department of Liver Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Hepatology. 2021 Sep;74(3):1339-1356. doi: 10.1002/hep.31766.
The dynamic N6-methyladenosine (m A) mRNA modification is essential for acute stress response and cancer progression. Sublethal heat stress from insufficient radiofrequency ablation (IRFA) has been confirmed to promote HCC progression; however, whether m A machinery is involved in IRFA-induced HCC recurrence remains open for study.
Using an IRFA HCC orthotopic mouse model, we detected a higher level of m A reader YTH N6-methyladenosine RNA binding protein 1-3 (YTHDF1) in the sublethal-heat-exposed transitional zone close to the ablation center than that in the farther area. In addition, we validated the increased m A modification and elevated YTHDF1 protein level in sublethal-heat-treated HCC cell lines, HCC patient-derived xenograft (PDX) mouse model, and patients' HCC tissues. Functionally, gain-of-function/loss-of-function assays showed that YTHDF1 promotes HCC cell viability and metastasis. Knockdown of YTHDF1 drastically restrains the tumor metastasis evoked by sublethal heat treatment in tail vein injection lung metastasis and orthotopic HCC mouse models. Mechanistically, we found that sublethal heat treatment increases epidermal factor growth receptor (EGFR) m A modification in the vicinity of the 5' untranslated region and promotes its binding with YTHDF1, which enhances the translation of EGFR mRNA. The sublethal-heat-induced up-regulation of EGFR level was further confirmed in the IRFA HCC PDX mouse model and patients' tissues. Combination of YTHDF1 silencing and EGFR inhibition suppressed the malignancies of HCC cells synergically.
The m A-YTHDF1-EGFR axis promotes HCC progression after IRFA, supporting the rationale for targeting m A machinery combined with EGFR inhibitors to suppress HCC metastasis after RFA.
动态N6-甲基腺苷（m⁶A）mRNA修饰对于急性应激反应和癌症进展至关重要。已证实，射频消融不足（IRFA）引起的亚致死热应激会促进肝癌进展；然而，m⁶A机制是否参与IRFA诱导的肝癌复发仍有待研究。
利用IRFA肝癌原位小鼠模型，我们检测到，在靠近消融中心的亚致死热暴露过渡区，m⁶A阅读器YTH N6-甲基腺苷RNA结合蛋白1-3（YTHDF1）的水平高于较远区域。此外，我们在亚致死热处理的肝癌细胞系、肝癌患者来源的异种移植（PDX）小鼠模型和患者的肝癌组织中验证了m⁶A修饰增加和YTHDF1蛋白水平升高。在功能上，功能获得/功能丧失实验表明，YTHDF1促进肝癌细胞活力和转移。在尾静脉注射肺转移和原位肝癌小鼠模型中，敲低YTHDF1可显著抑制亚致死热处理诱发的肿瘤转移。从机制上讲，我们发现亚致死热处理会增加5'非翻译区附近的表皮生长因子受体（EGFR）m⁶A修饰，并促进其与YTHDF1的结合，从而增强EGFR mRNA的翻译。在IRFA肝癌PDX小鼠模型和患者组织中进一步证实了亚致死热诱导的EGFR水平上调。YTHDF1沉默与EGFR抑制联合使用可协同抑制肝癌细胞的恶性肿瘤。
m⁶A-YTHDF1-EGFR轴促进IRFA后的肝癌进展，支持靶向m⁶A机制联合EGFR抑制剂以抑制RFA后肝癌转移的理论依据。
