Dual-Aptamer-Targeted Immunomagnetic Nanoparticles to Accurately Explore the Correlations between Circulating Tumor Cells and Gastric Cancer

Abstract

It has been acknowledged that circulating tumor cells (CTCs) are promising biomarkers in liquid biopsy for cancer diagnosis and prognosis. However, the relationship between the CTC number and gastric cancer has scarcely been quantitatively investigated. Moreover, the single criterion of epithelial cell adhesion molecule (EpCAM) antibody/aptamer to specifically recognize epithelial CTCs cannot be universally applied for clinical applications, as it fails to recognize EpCAM-negative CTCs. Herein, we propose simple, low-cost, dual-aptamer (EpCAM and PTK7)modified immunomagnetic Fe 3 O 4 particles (IMNs) for efficient capture of heterogeneous CTCs and downstream analysis in gastric cancer patients. High PTK7 expression and a significant negative correlation between PTK7 and EpCAM expression were observed in primary gastric cancer tissues. Taking MGC-803 and BGC-823 cells as CTC models, the obtained dual-targeting IMNs could distinguishably recognize these cells with both high or low EpCAM and PTK7 expressions, which enhanced the accuracy of CTC recognition in gastric cancer. More than 95% of these two kinds of cells could be captured within 20 min of incubation, which was significantly more efficient than that of single EpCAM-or PTK7-modified IMNs. With this strategy, as low as five CTCs could be captured from phosphate-buffered saline (PBS), a cell mixture containing THP-1 cells, and lysed blood mediums. Moreover, the obtained CTCs can be used for subsequent gene analysis. Finally, the fabricated IMNs were successfully applied for CTC capture in 1.0 mL of peripheral blood samples from patients with gastric cancer. The detected CTC numbers in 72 participants were found to have close relationships with chemotherapy sensitivity, diagnosis, stage, and distant metastasis of patients. This work provides important references for further investigations on CTC-related diagnosis and individualized treatment.

Capture of Heterogeneous Circulating Tumor Cells in Colorectal Cancer Patients on an Immunomagnetic and Anti-Nonspecific Adsorption Platform

“…The chemical structure of Fe 3 O 4 @SiO 2 @PTMAO was further characterized by FT-IR. As shown in Figure E, the strong absorption peak at 579 cm –1 belonged to the characteristic peak of Fe 3 O 4 . The weak peak around 1090 cm –1 was produced by the SiOSi bond .…”

“…As shown in Figure 1E, the strong absorption peak at 579 cm −1 belonged to the characteristic peak of Fe 3 O 4 . 34 The weak peak around 1090 cm −1 was produced by the Si�O�Si bond. 37 The broad band in the region 3100−3500 cm −1 was attributed to the N�H stretching vibrations.…”

“…Biotin- or fluorescein-labeled EpCAM and CSV aptamers were synthesized by Sangon Biotech Co., Ltd. (Shanghai, China). The sequences of EpCAM and CSV aptamers were CACTA­CAGA­GGTTG­CGTCT­GTCCC­ACGTT­GTCAT­GGGGG­GTTG­GCCTG and CACGC­ATAGC­CTTTG­CTCCT­CGTCT­GGAAC­GTCGC­AGCTT­TAGTT­CTGGG­CCTAT­GCGTG, respectively. FITC-labeled CSV antibody was bought from Abnova.…”

“…The currently employed Canpatrol and CTCBIOPSY instruments for CTC isolation and typing are not only costly but also require at least 2.0 or even 5.0 mL of blood. Immunomagnetic nano- or microparticles functionalized with cell targeting agents (antibody or aptamer) have been widely proved to be promising CTC isolation strategies, which provide advantages of facile operation of magnetic separation from a biofluid sample, improved cell–material interactions, and enhanced cell capture efficiency . However, due to the severe nonspecific adsorptions by biomolecules, cells, and microorganisms in the complex blood environment, the capture performances are often reduced when CTC is captured from blood, which represents a great challenge for CTC research. , To create a clean and nonfouling surface used for CTC capture, we had the idea of using hydrophilic materials to modify the immunomagnetic interface.…”

Clinical application and detection techniques of liquid biopsy in gastric cancer

“…Bioenrichment relies on immunological antibodies, allowing for the specific capture of CTCs. This approach includes positive selection with antibodies against tumor-associated antigens such as EpCAM, CKs, mucin-1, human epidermal growth factor receptor 2, or epithelial growth factor receptor [50][51][52] and negative selection with antibodies against the common leukocyte antigen CD45 [53]. The CellSearch system (Veridex) is the most widely used antibody-based isolation technique and the only one approved by the Food and Drug Administration (FDA) for the detection of CTCs in the blood of some tumor patients [54][55][56], which has a greater benefit as a diagnostic and prognostic indicator for patients with metastatic disease [34,37].…”