糖皮质激素内分泌治疗胰腺癌的机理及药物动力学/药效动力学研究

Pancreatic cancer is one of the most aggressive forms of cancer, with a low mean 5-year survival rate of 3–5%, and it is the fourth leading cause of cancer-related death. Therefore, it is of great importance and urgency to find novel therapeutic targets and medications for the treatment of pancreatic cancer, and 90% of pancreatic cancer comes from pancreatic ductal adenocarcinoma (PDAC). Recently, emerging studies have found that the activation of estrogen receptor(ER) signaling pathways plays a pivotal role in the genesis and progression of several cancers, such as lung cancer and gastric cancers, which are traditionally considered as estrogen non-dependent cancers. Accordingly, blockage of estrogen signaling pathway appears to be a promising approach for these cancer treatment. It has been proven that glucocorticoids (GCs), including dexamethasone (DEX), produced significant tumor inhibition in breast cancer and non-small cell lung cancer as endocrine therapeutic agents, which is associated with induction of estrogen sulfotransferase (EST) and down-regulating the intratumoral estrogen level. However, the anti-estrogenic efficacy of GCs on PDAC, application of GCs to PDAC therapy as well as their modes of actions in tumor cells have not yet been well explored. Based on literature researches, as well as the promising outcomes of our recent preliminary studies of the inhibitory effects of GCs on the tumor growth of both SW1990 (a human PDAC cell line) xenografts and patient derived xenografts (PDX), we raised a hypothesis that the intervention of estrogen metabolism is one of the most important mechanisms in the treatment of PDAC by GCs. Our specific aims in the current research proposal accordingly are: (1) to investigate the function of ER signaling pathway in the treatment of PDAC using Elisa, real-time PCR, Western blot assay; (2) to evaluate the inhibitory effects of GCs on the proliferation of PDAC cells, and the anti-cancer effects of GCs on both xenograft models; (3) to elucidate the corresponding anti-cancer mechanisms on the basis of siRNA technique, flow cytometry analysis, immunohistochemical labelling, and so on; (4) to determine the concentrations of different GCs in both plasma and tumor tissues using LC-MS/MS methods and to evaluate their pharmacokinetic (PK) characteristics, and to establish the pharmacokinetic/pharmacodynamic (PK/PD) models of them, which would be further applied to predict and optimize dose regimens by simulations; (5) to characterize the relationship of anti-cancer effect between these two animal xenografts quantitatively and to preliminarily realize the in-vitro to in-vivo extrapolation and inter species extrapolation. It is our expectation that the results from conducting the proposed research projects could contribute greatly to: (i) finding novel therapeutic targets and medications for PDAC treatment; (ii) providing optimized regimens which may be referred to clinically. Furthermore, our future investigation will provide beneficial information to our understanding of PDAC and other adenocarcinomas, thus suggesting a broad application prospect of GCs.

对于恶性程度高且非常难治的胰腺癌，寻找新靶点和新药物迫在眉睫。近期研究证明雌激素受体(ER)通路对肺癌等“非激素依赖型”肿瘤的进展起重要作用，ER可作为此类癌症内分泌治疗的新靶点。糖皮质激素(GC)可降低瘤内雌激素水平来抑制乳腺和肺肿瘤的生长，但GC内分泌治疗胰腺癌的研究尚属空白。通过前期研究和文献调研提出假设：GC通过干预雌激素代谢等作用可以内分泌治疗胰腺癌。本研究拟通过RT-PCR、免疫组化等多种方法验证ER亚型在胰腺癌中的靶点作用；在人胰腺癌细胞和病人肿瘤组织接种的两种移植瘤模型中，考察系列GCs对胰腺癌的药效和安全性，主要考察内分泌治疗相关抗癌机理；评价不同GC的药动学(PK)和药效学(PD)性质并建立PK/PD模型，通过模型仿真优化治疗方案，并初步实现GCs从体外到体内、动物到人的大致外推。课题将为胰腺癌治疗提供新靶点、新药物和合理给药方案，具有重要理论价值和广阔的应用转化前景。

寻找有效治疗胰腺癌的靶点和药物十分急迫，雌激素受体（ER）可能成为“非激素依赖型”胰腺癌治疗的新靶点，糖皮质激素（GCs）在乳腺癌和肺癌中可起到抗雌激素的内分泌治疗作用。本项目探究了GCs干预雌激素水平而治疗胰腺癌的药效及机理，并建立PK/PD模型进行转化研究。..主要研究内容：①考察GCs对胰腺癌SW1990及PANC-1细胞的体外药效，对其作用于糖皮质激素受体（GR）及下游相关分子和EMT过程的相关机理进行验证；②建立胰腺癌细胞接种的荷瘤鼠模型及人源肿瘤组织接种的荷瘤鼠模型（PDX），考察GCs对肿瘤大小及瘤内相关信号分子的影响，分别采用GR特异性抑制剂RU486和雌激素合成酶特异性抑制剂来曲唑（LTZ）验证GR和ER的相关机理；③建立GCs抑制肿瘤生长的PK/PD模型，根据模型结果进行不同GCs间的体外-体内、临床前-临床的药效/剂量外推；④拓展考察地塞米松（DEX）与多巴胺D2亚型受体（D2DR）拮抗剂舒必利(SUL)联用治疗耐药性乳腺癌的药效与机理；建立同时量化药效和安全性影响的生存期模型。..重要结果和数据：①证实了GCs可通过上调EST表达，降低雌激素水平而抑制胰腺肿瘤生长的药效及内分泌相关机理；②证实了雌激素及不同ER亚型在胰腺癌发生发展中的作用，ERα表达较高的胰腺肿瘤对抗雌激素的内分泌治疗响应更好；③证实了GCs在GR高表达的胰腺肿瘤中通过激动GR、影响NF-κB p65、IL-6、VEGF和EMT过程等相关因子，发挥抗胰腺癌药效；④建立不同GCs在临床前移植瘤模型中治疗胰腺癌的PK/PD模型，建立体内药效参数与体外受体亲和性参数之间的相关性，进行体外-体内的外推；结合PK/PD模型结果与人体PK参数，外推GCs的临床有效剂量；⑤证实了SUL降低肿瘤干细胞比例而与DEX协同治疗耐药性乳腺癌的药效及机制；建立了定量描述肿瘤体积和动物体重变化的生存期模型。..研究意义：本研究证实了GCs抑制胰腺癌的药效和相关机理，为胰腺癌的精准治疗提供了合理治疗方案和定量参考依据。