Breast cancer is the most common cancer in women. Although chemotherapy is still broadly used in its treatment, adverse effects remain a challenge. In this scenario, aptamers emerge as a promising alternative for theranostic applications. Studies using breast cancer cell lines provide useful information in laboratory and preclinical investigations, most of which use cell lines established from metastatic sites. However, these cell lines correspond to cell populations of the late stage of tumor progression. On the other hand, studies using breast cancer cells established from primary sites make it possible to search for new theranostic approaches in the early stages of the disease. Therefore, this work aimed to select RNA aptamers internalized by MGSO-3 cells, a human breast cancer cell line, derived from a primary site previously established in our laboratory. Using the Cell-Internalization SELEX method, we have selected two candidate aptamers (ApBC1 and ApBC2). We evaluated their internalization efficiencies, specificities, cellular localization by Reverse Transcription-qPCR (RT-qPCR) and confocal microscopy assays. The results suggest that both aptamers were efficiently internalized by human breast cancer cells, MACL-1, MDA-MB-231, and especially by MGSO-3 cells. Furthermore, both aptamers could effectively distinguish human breast cancer cells derived from normal human mammary cell (MCF 10A) and prostate cancer cell (PC3) lines. Therefore, ApBC1 and ApBC2 could be promising candidate molecules for theranostic applications, even in the early stages of tumor progression.

中文翻译：

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选择内化 RNA 适体进入源自原发位点的人乳腺癌细胞

乳腺癌是女性最常见的癌症。尽管化疗仍广泛用于其治疗，但副作用仍然是一个挑战。在这种情况下，适体成为治疗诊断应用的一种有前途的替代品。使用乳腺癌细胞系的研究为实验室和临床前研究提供了有用的信息，其中大多数使用从转移部位建立的细胞系。然而，这些细胞系对应于肿瘤进展晚期的细胞群。另一方面，使用从原发部位建立的乳腺癌细胞进行的研究使得在疾病的早期阶段寻找新的治疗诊断方法成为可能。因此，这项工作旨在选择由 MGSO-3 细胞内化的 RNA 适体，MGSO-3 细胞是一种人乳腺癌细胞系，源自我们实验室先前建立的原发位点。使用 Cell-Internalization SELEX 方法，我们选择了两个候选适体（ApBC1 和 ApBC2）。我们通过逆转录 qPCR (RT-qPCR) 和共聚焦显微镜检测评估了它们的内化效率、特异性、细胞定位。结果表明，两种适体均被人乳腺癌细胞 MACL-1、MDA-MB-231，尤其是 MGSO-3 细胞有效内化。此外，两种适体都能有效区分源自正常人乳腺细胞（MCF 10A）和前列腺癌细胞（PC3）系的人乳腺癌细胞。因此，即使在肿瘤进展的早期阶段，ApBC1 和 ApBC2 也可能成为治疗诊断应用的有希望的候选分子。