乏氧微环境中HIF-1α/STAT3激活ZIP4促进头颈部鳞状细胞癌侵袭转移的机制研究

Abnormal activation of HIF-1α and STAT3 can mediate hypoxia resistance and invasion or metastasis in cancer cell. Our preliminary study indicated that ZIP4 was highly expressed in invasive front and co-localized with EGFR in HNSCC tumor samples. ZIP4 could be regulated by HIF-1α and STAT3 and the underling mechanism is still unclear. Thus, we propose the research hypothesis that HIF-1α/STAT3 triggers ZIP4 transcription to promote invasion and metastasis in HNSCC under hypoxia stress. In the current research program, we will study as follows: the expression character of HIF-1α/STAT3 and ZIP4/EGFR in the invasive front of HNSCC; the mechanism that HIF-1α/STAT3 triggers ZIP4 transcription; the downstream target genes regulated by ZIP4; the interaction mechanism between ZIP4 and EGFR under different Zn2+ concentration in vitro and in vivo. Expected research results will elucidate that HIF-1α/STAT3 triggers ZIP4 transcription to form cancer invasive front in HNSCC under hypoxia stress and provide novel strategy based on targeting HIF-1α/STAT3/EGFR to treat HNSCC.

HIF-1α和STAT3异常激活能介导肿瘤细胞参与乏氧耐受和侵袭转移。我们前期工作发现ZIP4在头颈部鳞状细胞癌（HNSCC）侵袭前缘表达增高并与EGFR共定位；ZIP4可能受HIF-1α和STAT3调控但具体机制不明。据此，我们提出“乏氧微环境中HIF-1α/STAT3转录激活ZIP4促进HNSCC侵袭转移”的科学假说。本项目拟开展：在HNSCC侵袭前缘肿瘤细胞中研究HIF-1α/STAT3与ZIP4/EGFR表达特征；在细胞系和动物模型中证明乏氧条件下HIF-1α/STAT3转录激活ZIP4；探究受ZIP4调节的下游靶基因；明确不同浓度锌离子对ZIP4/EGFR相互作用影响。预期结果阐明乏氧应激刺激下HIF-1α/STAT3调节ZIP4/EGFR参与肿瘤侵袭前缘形成的分子机制，为建立以ZIP4为核心针对HIF-1α/STAT3/EGFR通路治疗HNSCC新策略提供实验和理论依据。

本课题旨在阐明乏氧应激刺激下HIF-1α/STAT3调节ZIP4/EGFR参与肿瘤侵袭前缘形成的分子机制。本项研究首先阐明了ZIP4在HNSCC中高表达特征，并明确了ZIP4通过影响上皮间质转化调控HNSCC侵袭转移的作用机制。接下来，本研究对HNSCC中ZIP4调控机制做了初步探索，发现改变HIF-1α/STAT3表达水平影响ZIP4的mRNA和蛋白水平；活化的HIF-1α/STAT3分别和ZIP4启动子相应调控序列HRE和ISRE/GAS结合，共同启动ZIP4转录。第三，ZIP4通过和EGFR相互作用，影响HNSCC对cetuximab治疗敏感性。第四，ZIP4可以通过Caprin1/BDNF轴影响HNSCC神经侵犯。最后，本研究探索了ZIP4表观遗传学修饰，验证了ZIP4在N261位点存在糖基化修饰，并探索糖基化对ZIP4蛋白稳定性和功能发挥的重要作用。本课题组在British Journal of Cancer, Journal for Immuno Therapy of Cancer, Oncoimmunology等杂志发表SCI 论文共8篇(标注资助)，累计影响因子为55.643；另发表中文论文8篇。培养硕博士研究生共计12名；获得2020年度天津市科技进步二等奖。本研究通过明确ZIP4在HNSCC发生发展的中重要地位，为在HNSCC中开展以调控Zn2+或靶向ZIP4的治疗策略提供重要的理论依据和实验基础，同时指明了靶向ZIP4和抗EGFR治疗联合的“双靶策略”在HNSCC中重要应用前景，具有重要的转化医学意义。综上所述，本课题顺利完成了预定研究任务，达到了预期的效果。