PKD2调控上皮细胞间充质转化对肝癌索拉非尼耐药的影响及其机制研究

Sorafenib is the only targeted drug approved by US Food and Drug Administration for advanced hepatocellular carcinoma(HCC) . Sorafenib resistance significantly restricts the treatment effect of sorafenib on HCC. Epithelial mesenchymal transition (EMT)is a crucial process in tumor progression. EMT of tumor cells not only causes increased metastasis, but also contributes to drug resistance. Protein kinase D2(PKD2) plays an important and complicated role in cell proliferation,invasiveness as well as drug reisistance in many malignancies. However, little is known about the effect of PKD2 on drug resistance in HCC. We previously found that PKD2 regulated EMT of HCC both in vitro and in vivo. HCC cell lines with sorafenib resistance had upregulated expression of PKD2 and typical feature of EMT. We suppose that PKD2 could regulate sorafenib resistance of HCC through promoting EMT. We design to explore the role and mechanism of PKD2 in EMT and sorafenib resistance in HCC both in vitro and in vivo by artificial regulation of PKD2 expression using siRNA or plasmids. The relationship between PKD2 expression in clinical HCC tissue samples and sorafenib resistance as well as the prognosis of HCC patients will also be determined. Moreover, we will also investigate the effect of combination treatment of inhibitor of PKD2 and sorafenib in HCC both in vitro and in vivo. Our study would reveal a new regulatory mechanism in sorafenib resistance of HCC and may reveal new therapeutic targets for advanced HCC patients with sorafenib resistance.

索拉非尼是目前被批准用于晚期肝细胞癌的唯一靶向治疗药物，耐药的出现严重影响了索拉非尼的疗效。上皮细胞间充质转化(EMT) 是肝癌转移的基础，也是肝癌耐药的关键过程。蛋白激酶D2(PKD2) 参与调控多种肿瘤的增殖、侵袭和耐药，但其是否与肝癌的索拉非尼耐药相关目前未见报道。我们以往的研究发现，PKD2参与调控肝癌的EMT；索拉非尼耐药肝癌细胞中，PKD2表达上调，且耐药细胞呈现EMT特征；下调耐药细胞PKD2的表达可以增加细胞对索拉非尼的敏感性。这些结果提示PKD2可能通过调节EMT，诱导肝癌细胞对索拉非尼耐药。本项目拟在前期基础上，探究PKD2调控的EMT对肝癌索拉非尼耐药的影响及其调节机制；探讨PKD2与临床索拉非尼耐药的相关性；并通过抑制PKD2活性探索耐索拉非尼肝癌的治疗。本研究将进一步阐明肝癌索拉非尼耐药的机制，为索拉非尼耐药的晚期肝癌治疗寻找新的靶点。

索拉非尼是治疗晚期肝细胞癌的一线靶向药物，而耐药的出现严重影响了其疗效。上皮细胞间充质转化(EMT)是肝癌耐药的关键过程。蛋白激酶D2(PKD2)与肝癌的索拉非尼耐药是否相关目前未见报道。我们预实验发现，PKD2促进肝癌的EMT；索拉非尼耐药肝癌细胞呈现EMT特征，且PKD2表达上调；下调PKD2的表达可以增加耐药细胞对索拉非尼的敏感性。这些结果提示PKD2可能通过调节EMT，诱导肝癌细胞对索拉非尼耐药。.本项目研究进一步探究了PKD2对肝癌索拉非尼耐药及EMT的影响；探究了抑制PKD2活性对耐药肝癌的索拉非尼敏感性的影响；从转录因子水平探讨了PKD2调控肝癌索拉非尼耐药的下游机制；并初步探讨了PKD2的上游调控因子。此外，我们在临床标本中探讨了PKD2与患者索拉非尼疗效的相关性。.我们的主要研究结果如下：1. 体外细胞和小鼠肝癌模型中，敲低PKD2的表达可以增强索拉非尼对肝癌细胞的增殖及EMT的抑制作用，而过表达PKD2则可减弱索拉非尼的疗效。2.小鼠肝癌模型中，敲低PKD2的表达可以提高耐药肝癌细胞对索拉非尼的敏感性。3. PKD2通过促进转录因子Snail的表达，促进肝癌细胞对索拉非尼耐药。4.GNG12可以促进PKD2的活化，是PKD2调控肝癌耐药的上游调控分子。5.PKD2活化水平高的肝癌患者，对索拉非尼的反应较差、预后差。.综上所述，我们的研究结果表明，PKD2通过促进肝癌EMT促进肝癌细胞对索拉非尼耐药，而下调PKD2的表达可逆转肝癌索拉非尼耐药。GNG12通过促进PKD2的活化，增强转录因子Snail的表达，从而促进肝癌的耐药。我们的研究结果提示，靶向PKD2可能成为临床逆转肝癌索拉非尼耐药的新思路。