一种新型 RNA 适体将质膜 ATP 合酶β亚基鉴定为侵袭性癌症的早期标志物和治疗靶点。

PURPOSE: Primary breast and prostate cancers can be cured, but metastatic disease cannot. Identifying cell factors that predict metastatic potential could guide both prognosis and treatment. METHODS: We used Cell-SELEX to screen an RNA aptamer library for differential binding to prostate cancer cell lines with high vs. low metastatic potential. Mass spectroscopy, immunoblot, and immunohistochemistry were used to identify and validate aptamer targets. Aptamer properties were tested in vitro, in xenograft models, and in clinical biopsies. Gene expression datasets were queried for target associations in cancer. RESULTS: We identified a novel aptamer (Apt63) that binds to the beta subunit of FF ATP synthase (ATP5B), present on the plasma membrane of certain normal and cancer cells. Apt63 bound to plasma membranes of multiple aggressive breast and prostate cell lines, but not to normal breast and prostate epithelial cells, and weakly or not at all to non-metastasizing cancer cells; binding led to rapid cell death. A single intravenous injection of Apt63 induced rapid, tumor cell-selective binding and cytotoxicity in MDA-MB-231 xenograft tumors, associated with endonuclease G nuclear translocation and DNA fragmentation. Apt63 was not toxic to non-transformed epithelial cells in vitro or adjacent normal tissue in vivo. In breast cancer tissue arrays, plasma membrane staining with Apt63 correlated with tumor stage (p < 0.0001, n = 416) and was independent of other cancer markers. Across multiple datasets, ATP5B expression was significantly increased relative to normal tissue, and negatively correlated with metastasis-free (p = 0.0063, 0.00039, respectively) and overall (p = 0.050, 0.0198) survival. CONCLUSION: Ecto-ATP5B binding by Apt63 may disrupt an essential survival mechanism in a subset of tumors with high metastatic potential, and defines a novel category of cancers with potential vulnerability to ATP5B-targeted therapy. Apt63 is a unique tool for elucidating the function of surface ATP synthase, and potentially for predicting and treating metastatic breast and prostate cancer.

目的：原发性乳腺癌和前列腺癌可以治愈，但转移性疾病无法治愈。确定预测转移潜能的细胞因子可以指导预后和治疗。

方法：我们使用细胞 SELEX 筛选 RNA 适体文库，以筛选具有高转移潜能与低转移潜能的前列腺癌细胞系的差异结合。质谱、免疫印迹和免疫组化用于鉴定和验证适体靶标。在体外、异种移植模型和临床活检中测试适体特性。查询癌症中的基因表达数据集以确定靶标相关性。

结果：我们发现了一种新型适体（Apt63），它与 FF ATP 合酶的β亚基（ATP5B）结合，存在于某些正常和癌细胞的质膜上。Apt63 与多种侵袭性乳腺癌和前列腺癌细胞系的质膜结合，但不与正常乳腺和前列腺上皮细胞结合，与非转移性癌细胞的结合较弱或不存在；结合导致细胞迅速死亡。单次静脉注射 Apt63 可诱导 MDA-MB-231 异种移植肿瘤中肿瘤细胞选择性结合和细胞毒性，与内切核酸酶 G 核易位和 DNA 片段化相关。Apt63 在体外对非转化上皮细胞或体内相邻正常组织没有毒性。在乳腺癌组织阵列中，Apt63 的质膜染色与肿瘤分期相关（p<0.0001，n=416），与其他癌症标志物无关。在多个数据集上，ATP5B 的表达相对正常组织显著增加，并且与无转移生存（p=0.0063，0.00039）和总生存（p=0.050，0.0198）呈负相关。

结论：Apt63 与质膜外 ATP5B 的结合可能会破坏具有高转移潜能的肿瘤亚群中的一个重要生存机制，并定义了一类潜在易受 ATP5B 靶向治疗影响的新型癌症。Apt63 是阐明表面 ATP 合酶功能的独特工具，并且可能用于预测和治疗转移性乳腺癌和前列腺癌。