胰腺癌细胞分泌MVs-mir-221介导胰腺星状细胞活化的作用及机制探讨

Stellate cell activation is closely related to pancreatic cancer invasion and metastasis. Our previous study found that pancreatic cancer cells can secrete functional mir-221 carried by microvesicels, cause the upregulation of exogenous mir-221 in PSCs and induce its activity phenotype. This project intends to detect the founction of MVs-mir-221 and relevant signal pathway during PSCs activation in vivo and in vitro, identify the detailed mechanism in cross-talk between pancreatic cancer and stellate cell, explore the further effect on tumor invasion and metastasis, investigate the possibility of inhibiting pancreatic cancer invasion and metastasis by targeting MVs-miRNA. This project is based on the pancreatic pathophysiology characteristics, focus on secretory miRNA mediated information transmission; intend to provide new mechanism involved in the cross-talk between pancreatic cancer cell and stellate cell, explore new molecular targets and strategies for the prevention and treatment of pancreatic cancer. The implementation of this project will help further clarify the way of information exchange between the tumor cells and the microenvironment, expand new vision in the study of tumor development and eventually provide experimental basis for primary prevention for the malignant tumor.

胰腺癌微环境中星状细胞活化和胰腺癌侵袭转移密切相关。我们前期研究发现胰腺癌细胞可分泌以微泡（MVs）为载体的活性mir-221，导致PSCs中外源性mir-221表达上调，诱导其活化。本课题拟通过检测体内及体外共培养体系中MVs-mir-221与PSCs活性调节信号通路的关系，明确MVs-mir-221介导胰腺癌和胰腺星状细胞对话的机制及其在肿瘤侵袭转移中的作用；探讨以微环境中MVs-mir221为靶点抑制胰腺癌侵袭转移的可能性。本课题基于胰腺癌的病理生理学特征，从分泌性miRNA介导细胞间信息传递的角度，深入探讨胰腺癌细胞和星状细胞对话在胰腺癌侵袭转移中的分子机制，为胰腺癌的防治提供新靶点和新策略。本项目的实施有助于深入阐明肿瘤细胞和微环境之间的信息交流方式，为肿瘤发生发展的分子机制研究提供新思路，并为探索恶性肿瘤的一级预防措施提供实验依据。

既往研究表明细胞微环境在肿瘤的发生发展过程中发挥重要作用。胰腺星状细胞（PSCs）是构建胰腺癌肿瘤微环境最主要的基质细胞之一，具有静息与活化两种状态。活化PSCs与胰腺癌细胞（PCs）相互作用，促进PCs增殖、侵袭转移、免疫逃逸和放化疗耐受。然而细胞间信号转导机制尚不明确。本研究使用ATRA诱导PSCs去活化的作用；研究去活化PSCs对胰腺癌细胞增殖、侵袭的影响；分析去活化PSCs中miRNA表达谱变化；探讨PSCs与胰腺癌细胞之间相互作用的分子机制。我们发现ATRA处理原代胰腺星状细胞HPaSteC，可以诱导α-SMA、desmin mRNA及蛋白表达水平下调、抑制细胞的增殖。探讨不同状态PSCs与胰腺癌细胞共培养，对胰腺癌细胞生物学行为变化的影响，发现去活化PSCs促进AsPC-1、BxPC-3胰腺癌细胞增殖、侵袭的能力明显减弱。研究PSCs去活化miRNA表达谱差异，发现经ATRA处理的PSCs中，其细胞及外泌体miRNA-29的表达明显下调。共培养体系中胰腺癌细胞的miRAN-29表达水平与胰腺星状细胞及外泌体中的表达一致。通过调节PSCs细胞miRNA-29的表达可以影响其外泌体miRNA-29表达，从而影响共培养胰腺癌细胞的生物学行为改变。因此外泌体miRNA在胰腺癌与胰腺星状细胞的信号转导过程中发挥重要作用，可能参与胰腺癌的发生发展，通过调节胰腺星状细胞活化状态或者靶向外泌体miRNA可能在胰腺癌的诊治方面具有潜在的临床应用价值。