Monitoring of breast cancer progression via aptamer-based detection of circulating tumor cells in clinical blood samples

Abstract

Introduction: Breast cancer (BC) diagnostics lack noninvasive methods and procedures for screening and monitoring disease dynamics. Admitted CellSearch® is used for fluid biopsy and capture of circulating tumor cells of only epithelial origin. Here we describe an RNA aptamer (MDA231) for detecting BC cells in clinical samples, including blood. The MDA231 aptamer was originally selected against triple-negative breast cancer cell line MDA-MB-231 using cell-SELEX.Methods: The aptamer structure in solution was predicted using mFold program and molecular dynamic simulations. The affinity and specificity of the evolved aptamers were evaluated by flow cytometry and laser scanning microscopy on clinical tissues from breast cancer patients. CTCs were isolated form the patients’ blood using the developed method of aptamer-based magnetic separation. Breast cancer origin of CTCs was confirmed by cytological, RT-qPCR and Immunocytochemical analyses.Results: MDA231 can specifically recognize breast cancer cells in surgically resected tissues from patients with different molecular subtypes: triple-negative, Luminal A, and Luminal B, but not in benign tumors, lung cancer, glial tumor and healthy epithelial from lungs and breast. This RNA aptamer can identify cancer cells in complex cellular environments, including tumor biopsies (e.g., tumor tissues vs. margins) and clinical blood samples (e.g., circulating tumor cells). Breast cancer origin of the aptamer-based magnetically separated CTCs has been proved by immunocytochemistry and mammaglobin mRNA expression.Discussion: We suggest a simple, minimally-invasive breast cancer diagnostic method based on non-epithelial MDA231 aptamer-specific magnetic isolation of circulating tumor cells. Isolated cells are intact and can be utilized for molecular diagnostics purposes.

Selection of internalizing RNA aptamers into human breast cancer cells derived from primary sites

“…As mentioned previously, a significant part of our knowledge of breast cancer is based on studies carried out with cell lines obtained from metastatic sites. 7,8 These cell lines were also used in publications that performed Cell-SELEX and Cell-Internalization SELEX to select specific aptamers for different breast cancer cell subtypes: MCF-7, [27][28][29][30] MDA-MB-231, [31][32][33] TUBO, 29 and SK-BR-3 cells. 34 Another group developed a novel aptamer-based histochemistry assay to identify different breast cancer subtypes using cell lines MCF-7, SK-BR-3, MDA-MB-231 MCF-10A, and MF3Ec.…”

Research History, Current Trends, and Future Prospects of Liquid Biopsy in Triple-Negative Breast Cancer: An Analysis from a Global Perspective

“…The migratory properties of CTC present opportunities for enhancing early diagnosis, re ning therapeutic approaches through speci c target or biomarker identi cation, and providing prognostic value, including predicting the likelihood of recurrence [13]. Studies based on liquid biopsy techniques have explored multiple factors contributing to the spread of TNBC tumors.…”

Recent Progress in Enhanced Cancer Diagnosis, Prognosis, and Monitoring Using a Combined Analysis of the Number of Circulating Tumor Cells (CTCs) and Other Clinical Parameters

“…Moreover, with the application of aptamers, research on designing different aptamers for the purpose of more specific and comprehensive CTC detection is also increasing. The application of DNA or RNA aptamers has already produced impressive results in lung and breast cancer [160,161]. Especially in the detection of CTCs in non-epithelial cell cancers such as glial brain tumors, the application of aptamers also has considerable potential [162].…”