RRM2诱导宫颈癌细胞上皮-间质转化的机制研究

Cervical cancer is the second leading cause of cancer-related mortalities in women worldwide, invasion and metastasis of which is the leading cause of death in patients.Epithelial-mesenchymal transition(EMT) has played an important role in cancer metastasis. Studies have shown that HPV related cervical cancer has much higher invasion and metastasis rate and HPVE7 could cause EMT to epithelium, but the mechanism underlying them is unknown. RRM2 is highly expressed in a variety of cancers and invovled in the invasion and metastasis of cancer. Our previous work showed that RRM2 is transcriptionally regulated by HPVE7 and can promote the invasion and metastasis and EMT of cervical cancer cells，which is dependent on the activity of ERK signaling pathway. In this project, we will further investigate whether HPVE7/RRM2/ROS/PLD/PA/Raf/MAPK/EMT pathway is invovled in RRM2 mediated invasion and metastasis of cervical cancer and whether RRM2 could be an independent indicator about prognosis and relapse of cervical cancer. Through studies in cell culture systems, animal models and clinical specimen, we wish to clarify the relationship between expression of RRM2 and HPV infecion/cervical cancer clinical pathological parameter. We also wish to verify that ROS mediates RRM2 caused EMT in cervical cancer by activating PLD which can promote Raf translocation to cell membrance and activate ERK signaling pathway.The above studies will provide an insight into the mechanism of HPVE7 carcinogenesis which may lead to new therapeutic targets and better anticancer strategies.

宫颈癌位居全世界女性恶性肿瘤死亡率第二位，肿瘤侵袭转移是患者死亡主要原因，而上皮-间质转化（EMT）是肿瘤侵袭转移的重要机制。HPV导致的宫颈癌侵袭转移率高，HPVE7能导致细胞EMT，但确切的机制尚不清楚。RRM2基因高表达能促进多种肿瘤侵袭转移而具体机制不明。我们前期研究发现RRM2是E7下游靶基因，RRM2能增强宫颈癌细胞侵袭转移和EMT发生，这与ERK通路激活相关。本项目将在此基础上探讨宫颈癌是否通过HPVE7/RRM2/ROS/PLD/PA/Raf/MAPK/EMT途径促进侵袭转移，RRM2能否作为判断宫颈癌预后和复发的新指标。拟通过病例研究、体外细胞和动物实验来明确RRM2表达与宫颈癌临床病理指标和HPV感染的关系；验证RRM2是否通过ROS激活PLD，促Raf上膜活化ERK，致EMT发生。本项目将为深入揭示HPVE7下游致癌通路提供新线索，为发现新宫颈癌治疗靶标奠定基础。

宫颈癌在全球女性恶性肿瘤中发病率位居第二位，肿瘤侵袭转移是患者死亡的主要原因，而上皮-间质转化（EMT）是肿瘤侵袭转移的重要机制。HPV导致的宫颈癌是一个多步骤、多因素且侵袭转移率高的恶性肿瘤，HPVE7能导致细胞EMT，但确切的机制尚不清楚。相关文献报道，RRM2基因高表达能促进多种肿瘤侵袭转移而具体机制不明。我们前期研究发现RRM2是E7下游靶基因，RRM2能增强宫颈癌细胞侵袭转移和EMT发生与ERK通路激活相关。在此基础上，本项目运用免疫组化实验在组织水平确定了RRM2表达与宫颈癌临床分期、局部浸润程度、淋巴结转移、肿瘤复发和生存率的关系，发现RRM2与宫颈癌分期和生存率相关，并可以作为宫颈癌预后的独立指标。进一步在细胞系中运用siRNA干扰和流式细胞试验发现下调RRM2表达可抑制细胞增殖，细胞周期G1期阻滞，发生细胞凋亡等细胞生物学特性发生改变。其机制可能与RRM2过表达增强宫颈癌细胞内活性氧(ROS)的水平，进而激活PI3K/Akt调控E-cadherin的表达促进宫颈癌细胞的侵袭转移相关。鉴于以上结果，我们构建了稳转细胞系，在动物模型中对RRM2在裸鼠体内生长及转移的影响以及EMT相关标志蛋白之间的相关性进行验证，发现稳定低表达的RRM2可以抑制肿瘤的生长，并抑制了AKT的活化。通过本项目的研究初步确定RRM2通过ROS活化PI3K/Akt促进宫颈癌EMT的分子机制，为深入揭示HPVE7下游致癌通路提供新线索，为RRM2作为新的宫颈癌转移预测指标和治疗靶标点提供重要的理论和实验依据。