ROS-MAPK-SOCS1信号通路在肝移植术后肝癌复发中的机制研究

Liver transplantation is currently one of the main therapies for liver carcinoma. However, tumor recurrence and lack of sensitive molecular markers for early diagnosis, seriously deteriorate prognosis. Our previous data showed tumor suppressor gene SOCS1 methylation was significantly associated with tumor recurrence post LT, but the detailed mechanism is unknown. Reactive oxygen Species (ROS) are the main products of ischemia-reperfusion injury, which induce MAPK activation and promote tumor recurrence. SOCS1 gene knockout cell can produce more ROS, which showed SOCS1 inhibit ROS. So we proposed ROS may induce MAPK activation and expression, which regulate SOCS1 methylation, result in tumor recurrence. In this study, the expression of MAPK (JNK, P38, ERK), phosphorylation status, and expression of SOCS1 in vitro cell line and in vivo animal model with ischemia-reperfusion injury, will be monitored, to explore ROS-induced MAPK activation, so as to regulate SOCS1 methylation, result in liver cancer recurrence. A molecular marker-based early warning system can be established by learning this mechanism. Blocking SOCS1 methylation, MAPK inhibitor could be the effective methods for prevention and treatment for HCC recurrence post transplantation.

肝移植是治疗肝癌的有效手段之一。但移植术后肝癌复发，且缺乏高效敏感的早期诊断标志物，严重影响预后。我们前期研究发现，抑癌基因SOCS1甲基化与移植术后肝癌复发显著相关，但机制不明；移植肝缺血再灌注损伤主要产物ROS，诱导MAPK活化，促进肝癌复发；SOCS1基因敲除能增加ROS产生，提示SOCS1抑制ROS。基于此，我们设想：ROS可能通过调节MAPK表达和活性，诱导SOCS1甲基化，致肝移植术后肝癌复发。本课题拟通过模拟体外和体内缺血再灌注背景，检测MAPK（JNK，P38，ERK）表达水平、磷酸化状态、SOCS1表达和甲基化水平，探讨ROS诱导MAPK活化、调控SOCS1甲基化的肝癌复发机制，寻找肝癌复发早期预警的敏感标志物，并利用临床样本证实这一机制。阻断SOCS1甲基化的药物、MAPK的抑制剂，将可能成为防治移植术后肝癌复发的有效药物。

背景：CDK蛋白家族的抑制剂已被批准用于多种肿瘤的治疗，然而，仅使用这类药物往往无效，并引起不良副作用。开发与CDK抑制剂联合应用的新药有望提高治疗效果。.方法：我们鉴定了细胞因子信号转导抑制因子1(SOCS1)在肝细胞癌(HCC)细胞模型和异种小鼠模型中的功能。通过转录组测序、Western blot和Co-IP验证了SOCS1调控细胞增殖的分子机制。.研究结果：当SOCS1的表达被人为上调时，肝癌细胞系被阻滞在细胞周期的G1-S过渡阶段。有趣的是，在此过程中，CyclinD1蛋白总量增加，但有效比例降低。我们发现细胞核中CyclinD1的缺失可能是由于基于泛素的P21和P27的降解导致细胞核CyclinD1稳定性降低，从而抑制了细胞周期向S期的进展。在P21表达增加后，使CyclinD1失活的成分水平如预期的那样下降。结果表明，P21对肿瘤有一定的促癌作用。.总结：SOCS1作为HCC中的一种肿瘤抑制因子，是预测预后、肿瘤大小和切除后长期生存的良好指标。SOCS1有望与CDK家族抑制剂联合成为药物靶点。