蟾酥有效组份调控HIF-1α/EMT抑制索拉非尼治疗后肝癌侵袭转移的分子机制研究

Antiangiogenic drug sorafenib is a major drug to treat hepatic carcinoma，but the invasion and metastasis limits its clinical efficacy after treatment. The activation of HIF-1α/EMT under hypoxia environment caused by antiangiogenic is the major pathway to regulate invasion and metastasis. Chinese traditional medicine assumes “aidu” running contributes to tumor metastasis,and detoxifying herbs have the effect to inhibit tumor metastasis.In our previous studies,we found that bufalin,an effective ingredient of detoxifying herbs Toad cake,can downregulate HIF-1α and inhibit EMT.In addition,Bufalin can synerize with sorafenib and inhibit sorafenib induced-invasion and metastasis in an orthotopic xenograft model. Therefore, we assume that bufalin, the effective component of Toad cake may inhibit sorafenib-induced invasion and metastasis in hepatic carcinoma by inhibiting EMT via downregulating HIF-1α. In this study, hypoxic microenvironment is simulated in vitro, through which we aim to investigate the relevant molecular pathways involved in the inhibition of sorafenib-induced invasion and metastasis. To further confirm and validate our hypothesis, we also conduct in vivo studies. The study will provide collaborative route of administration of TCM for improve the efficacy of targeted drugs which widely used in cancer therapy to inhibit angiogenesis

抗血管生成药物索拉非尼（Sorafenib）是治疗肝癌的主要药物，但治疗后促进侵袭转移限制了其临床疗效。抗血管生成导致的乏氧激活HIF-1α/EMT是调控侵袭转移的主要通路。中医“癌毒”学说认为癌毒流注是肿瘤转移的原因，解毒中药具有抑制肿瘤转移的功效。我们前期研究发现解毒中药蟾酥有效组份蟾毒灵可下调HIF-1α并抑制EMT发生；且与索拉非尼有协同作用，并抑制索拉非尼治疗后肝癌裸鼠原位移植瘤侵袭转移能力。因此，我们认为蟾酥有效组份蟾毒灵抑制索拉非尼治疗后肝癌侵袭转移与干预HIF-1α/EMT信号传递过程有关。本课题将在体外模拟乏氧微环境，研究协同调控HIF-1α/EMT信号传递过程降低索拉非尼诱导的肝癌侵袭转移能力的相关分子机制，并在体内进行生物学验证，阐明其协同作用的可能机制。研究结果将为广泛应用于肿瘤治疗的抑制血管生成的靶向药物的疗效提高，提供中医药协同作用的途径.

索拉非尼治疗后诱发的肿瘤侵袭转移限制了其临床有效性，研究报道治疗后HIF-1α/EMT通路的激活是导致肿瘤转移的主要原因。我们前期研究发现蟾毒灵能够下调HIF-1α抑制肝癌侵袭转移。因此我们推测蟾毒灵调控HIF-1α/EMT抑制索拉非尼治疗后肝癌侵袭转移。本研究发现蟾毒灵和索拉非尼在体外具有协同作用，在最佳协同剂量下，蟾毒灵和索拉非尼联合能够显著抑制肝癌细胞侵袭迁移，同时体内两种药物的联合抑制肝原位肿瘤的生长。在乏氧条件下，蟾毒灵和索拉菲尼联合下调HIF-1α的表达，下调EMT过程中间质标志物N-cadherin和Vimentin，同时伴随着上皮标志物E-cadherin表达增加。机制研究发现，HIF-1α的表达和EMT转录因子Snail有显著正相关关系。在乏氧条件下，蟾毒灵和索拉菲尼联合显著下调Snail的表达。敲低Snail的表达，蟾毒灵和索拉菲尼联合对EMT的抑制减弱，同时细胞的侵袭转移能力减弱。综上，蟾毒灵联合索拉菲尼能够通过抑制HIF-1α/Snail介导的细胞EMT过程，从而抑制肝癌的侵袭转移。最后，本研究结果为提高抗血管生成靶向治疗药物的临床疗效提供了中医药协同作用的途径，同时为中药蟾毒灵的临床应用提供理论基础。