GPNMB诱导休眠胆囊癌细胞的干细胞特性的机制研究

Gallbladder cancer (GBC) is a high malignant cancer and its pathogenesis is still unknown. Gallbladder cancer stem cell (GBCSC) is closely correlated with tumorigenesis and development of gallbladder cancer. I have reported that the transmembrane glycoprotein nmb (GPNMB) was highly expressed in breast cancer stem cell (BCSC), and its expression location in BCSC was altered. GPNMB was exposed on the cell surface of BCSC and promoted the acquisition of stem cell-like properties of breast cancer cells. Furthermore, the tyrosine residue in GPNMB was found to play a decisive role in regulating the expression of stem cell marker genes. However, the roles of GPNMB in GBCSC have not been clarified. In the pre-experiments, we found that GPNMB was highly expressed in GBCSC and the expression of stem cell marker genes was also significantly increased. Moreover, the expression of GPNMB was detected on the cell surface of GBCSC. Therefore, we assume that GPNMB could promote the oncogenesis and metastasis of gallbladder cancer by regulating GBCSC characteristics. This project will further explore the expression and distribution of GPNMB in patients’ gallbladder cancer tissues and its correlation with clinical pathology and prognosis. The role of GPNMB in the progress of gallbladder cancer was investigated by using animal models. We will further inhibit GPNMB activity to elucidate the signaling pathway of how GPNMB and its synergistic differential expression genes regulate the characteristics of dormant GBCSC. This study will provide a new theoretical basis for targeted therapy of cancer stem cells.

胆囊癌恶性程度高，发病机制不明；胆囊癌干细胞（GBCSC）与胆囊癌的发生发展密切相关。申请人前期报道了，跨膜糖蛋白GPNMB在乳腺癌干细胞（BCSC）中高表达,同时其在BCSC中表达定位发生改变，暴露于膜表面的GPNMB促使乳腺癌细胞获得干细胞样特性，并且发现GPNMB的酪氨酸残基，在调控干细胞基因表达中起决定性作用。但是GPNMB在GBCSC中的作用尚未阐明。本课题预实验发现GPNMB在GBCSC中高表达，同时干细胞标志基因也显著升高，并检测到GBCSC膜表面GPNMB。据此我们推测，GPNMB通过调控GBCSC特性来促进胆囊癌发生和转移。本课题拟进一步探究GPNMB在胆囊癌病人组织中的表达分布及与临床病理、预后的相关性；采用动物模型，明确GPNMB在胆囊癌疾病进程中的作用；抑制GPNMB活性，阐明其协同差异基因调控休眠GBCSC特性的信号通路，为肿瘤干细胞靶向性治疗提供新的理论依据。

胆囊癌是胆道系统最常见的恶性肿瘤，在世界范围内高发于南美洲印第安人，印度北部地区，在中美洲、中欧和东欧，日本和中国也很常见。胆囊癌的早期发现比较困难，然而其恶性程度较高，易发生浸润性转移，临床预后极差。胆囊癌确诊后仅有15～47％的切除率；5年总体生存率接近3％，根治性切除术后也只有16.5％左右。通过建立胆囊癌类器官模型，发现GPNMB、干细胞标志基因NANOG和CD44、和EMT诱导转录基因SNAIL，在胆囊癌干细胞中高表达。利用通过特征图（FeaturePlot）和小提琴图（ViolinPlot）展示目的基因在所有细胞亚群（或分组）中有较大的表达分布差异。研究揭示了胆囊癌干细胞自我更新的调控作用及分子网络机制，GPNMB具有调控胆囊癌干细胞自我更新及胆囊癌发生的机理，明确GPNMB作为胆囊癌干预新靶点的临床意义，为胆囊癌的临床诊断标志物和抗癌药物的开发提供理论依据。