CCL5-CCR5介导的肾癌“干性”调控研究：基于间充质干细胞与肾癌“对话”机制

The metastatic and recurrent Renal Cell Carcinoma lead to an poor prognosis for RCC patients. The increase of stemness characteristic is one of the important mechanisms which cause tumor metastasis and recurrence. Currently, the potential regulatory mechanisms for stemness ability are still unclear. Previous studies mainly focused on the disorder by endogenous signaling pathway, few of which focused on the interaction between RCC and tumor microenvironment (TME). The tumor and the surrounding microenvironment are closely related and interact constantly by paracrine and endocrine. Bone marrow mesenchymal stem cells (BM-MSCs) is one of the most important stromal cells in tumor micro environment. BM-MSCs is one of the circulating immune cell located in the bone marrow which can be recruited into the tumor site specifically, and also the accumulating evidences showed the important role in promoting malignant tumor progression. In our study, we found that the circulating BM-MSCs can be recruited into renal tumor sites and increased the metastatic ability of RCC. We further revealed that the increased metastatic ability of RCC was due to the increased stem population in renal tumors. CCL5-CCR5 signal pathway was dominantly up-regulated in in vivo and in vitro experiments. In this study, we’d like to dissect the CCL5-CCR5 signal roles and potential mechanisms during the interaction process between RCC and BM-MSCs by molecular and cellular experiments. Hopefully we can find a new and more effective approach for mRCC treatment by CCL5-CCR5 signal blockage treatment.

肾细胞癌转移与复发是导致患者预后不良的主要原因。肿瘤干细胞特性的增加是导致肿瘤转移与复发的重要机制。当前对于肾细胞癌“干性”的调节机制尚不明确。既往研究多聚焦于肾细胞癌内源性信号通路的失调，对于“肿瘤微环境”诱发的信号与肿瘤细胞间的“对话”过程缺乏关注。骨髓间充质干细胞是存在于肿瘤微环境中重要的间质细胞。预实验发现肾细胞癌能够特异性招募骨髓间充质干细胞，通过与间充质细胞的交互性“对话”增加肿瘤细胞“干性”而促进肿瘤进展，同时伴有CCL5-CCR5信号的特异性激活。因此我们假设：CCL5-CCR5信号特异性介导肾细胞癌“干性”调节过程，其有可能成为进展期肾细胞癌治疗靶点。本研究拟通过临床标本研究明确异常激活CCL5-CCR5信号与肿瘤特异性招募骨髓间充质干细胞间的相关性，应用分子生物学、细胞学实验方法验证CCL5-CCR5信号通路介导的肾细胞癌与骨髓间充质干细胞间“对话”机制及潜在治疗价值。

骨髓间充质干细胞(BM-MSCs)是存在于肿瘤微环境中重要的效应细胞，是存在于骨髓中的初代骨细胞，在骨质形成、组织修复过程中发挥了重要作用。近期研究证实间充质干细胞具有“肿瘤趋向性”，恶性肿瘤细胞通过自分泌及旁分泌的形式趋化间充质干细胞进入原发肿瘤局部，二者间通过细胞间的“交互对话”过程促进肿瘤恶性进展，而在肾细胞癌中的作用尚未证实。CCL5作为一种趋化因子参与炎症反应和介导白细胞（T细胞）的游走和浸润，近年来报道证实其直接参与恶性肿瘤进展过程。基于上述背景，我们推测BM-MSCs通过CCL5-CCR5信号参与肾癌细胞分化过程，在肾细胞癌进展中可能发挥至关重要作用。.本课题通过离体和在体实验发现，透明细胞肾癌能够招募骨髓间充质干细胞聚集；进一步实验表明，骨髓间充质干细胞与肾癌细胞系（RCC）共培养后，能够促进肾癌细胞的侵袭、迁移过程；提取共培养条件培养基后，检测到细胞因子CCL5的浓度明显升高；通过外源性加入重组人CCL5，可增加RCC侵袭迁移指标的表达并激活PI3K/pAkt/mTOR通路，加入CCR5抑制剂Maraviroc可以抑制相关变化；提取肾癌患者的临床标本进行表达及预后相关分析；最后通过裸鼠体内实验验证体外细胞实验结果。.在离体试验中，CCL5参与了BM-MSCs与RCC的交互对话过程，阻断其信号可显著逆转细胞侵袭迁移能力；CCL5表达水平与肾透明细胞癌患者病理特征及预后关系密切；BM-MSCs能促进肾癌裸鼠瘤的生长，增加肿瘤的恶性程度，且细胞生物学特性良好。研究骨髓间充质干细胞对肾癌细胞系的影响能为临床治疗提供依据和参考，CCL5异常高表达可能是促进肾透明细胞癌发生发展的重要原因，并有可能作为肾透明细胞癌早期检测指标及潜在治疗靶点，具有较高的临床应用价值。

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