Wu Chiao-En, Chen Chiao-Ping, Pan Yi-Ru, Jung Shih-Ming, Chang John Wen-Cheng, Chen Jen-Shi, Yeh Chun-Nan, Lunec John
Division of Haematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou Branch, Chang Gung University College of Medicine Taoyuan, Taiwan.
Liver Research Center, Chang Gung Memorial Hospital Linkou, Taoyuan, Taiwan.
Am J Cancer Res. 2022 Sep 15;12(9):4399-4410. eCollection 2022.
Intrahepatic cholangiocarcinoma (iCCA) is an adenocarcinoma arising from the intrahepatic bile duct and accounts for the second highest incidence of primary liver cancers after hepatocellular carcinoma. The lack of effective treatment leads to a poor prognosis for advanced iCCA, so new targeted therapy is needed. The impairment of wild-type (WT) p53 tumor suppressor function by its negative regulators frequently occurs in iCCA. Therefore, restoration of WT p53 function by inhibiting its negative regulators is a therapeutic strategy being explored for cancer treatment. Combining an MDM2 inhibitor (MDM2i, RG7388) to stabilize p53 and a WIP1 inhibitor (WIP1i, GSK2830371) to increase p53 phosphorylation enhances p53 function. The combination of MDM2 and WIP1 inhibitors has been reported in several cancer types but studies are lacking. In the current study, liver adenocarcinoma cell lines, RBE and SK-Hep-1, were treated with RG7388 alone and in combination with GSK2830371. Cell proliferation, clonogenicity, protein and mRNA expressions, and cell cycle distribution were performed to investigate the effect and mechanism of growth suppression. To evaluate the antitumor efficacy of RG7388 and GSK2830371 , SK-Hep-1 xenografts in NOD-SCID mice were treated with combination therapy for two weeks. The combination of MDM2i and WIP1i significantly increased the growth inhibition, cytotoxicty, p53 protein expression, and phosphorylation (Ser15), leading to transactivation of downstream targets (p21 and MDM2). The results demonstrated that the combination treatment can significantly inhibit tumor growth. In this study, the liver adenocarcinoma cell lines responded to combination treatment via reactivation of p53 function evidenced by increased p53 expression, phosphorylation and expression of its downstream targets. This efficacy was also demonstrated . The current research provides a novel strategy for targeting the p53 pathway in liver adenocarcinoma that warrants further investigation.
肝内胆管癌（iCCA）是一种起源于肝内胆管的腺癌，其发病率在原发性肝癌中仅次于肝细胞癌，位居第二。缺乏有效的治疗方法导致晚期iCCA预后较差，因此需要新的靶向治疗。野生型（WT）p53肿瘤抑制功能被其负调节因子损害的情况在iCCA中经常发生。因此，通过抑制其负调节因子来恢复WT p53功能是一种正在探索的癌症治疗策略。联合使用MDM2抑制剂（MDM2i，RG7388）来稳定p53和WIP1抑制剂（WIP1i，GSK2830371）来增加p53磷酸化可增强p53功能。MDM2和WIP1抑制剂的联合应用在几种癌症类型中已有报道，但相关研究较少。在本研究中，肝腺癌细胞系RBE和SK-Hep-1分别用RG7388单独处理以及与GSK2830371联合处理。通过检测细胞增殖、克隆形成能力、蛋白质和mRNA表达以及细胞周期分布来研究生长抑制的作用和机制。为了评估RG7388和GSK2830371的抗肿瘤疗效，对NOD-SCID小鼠体内的SK-Hep-1异种移植瘤进行联合治疗两周。MDM2i和WIP1i联合使用显著增强了生长抑制、细胞毒性、p53蛋白表达及其磷酸化（Ser15），导致下游靶点（p21和MDM2）的反式激活。结果表明联合治疗可显著抑制肿瘤生长。在本研究中，肝腺癌细胞系通过p53功能的重新激活对联合治疗产生反应，表现为p53表达增加、磷酸化及其下游靶点的表达增加。这种疗效也得到了证实。目前的研究为靶向肝腺癌中的p53通路提供了一种新策略，值得进一步研究。
