posted on 2022-12-30, 16:12authored byYanbing Lu, Xin Li, Yun Liu, Jiabin Li, Zhezhou Chen, Xianmeng Meng, Wanming Li, Jin Fang
Liquid biopsy provides non-invasive and real-time detection
for
cancer diagnosis, but the lack of specific markers targeted to liquid
biopsy components, such as circulating tumor cells (CTCs) and exosomes,
has impeded its effective utilization in clinical settings. W3 is
an aptamer, and its target has been previously demonstrated to be
a predictor of colorectal cancer (CRC) metastasis. Herein, we developed
a W3-based molecular beacon (MAB-W3-3G) to specifically detect CTCs
and exosomes derived from CRC patients by modifying the W3 sequence
and adding a fluorescent group FAM at the 5′ end and a quencher
group BHQ1 at the 3′ end, resulting in a detectable green fluorescence
only in the presence of the target. MAB-W3-3G retained features similar
to those of the original W3, including high specificity and affinity
for metastatic CRC cells, as well as excellent plasma stability. Notably,
W3 target-positive CTCs were visualized, positive exosomes were quantified
in CRC patients’ whole blood without any sample pretreatment,
and both detections could be finished in one step without any routine
washing procedures. For CRC, the W3 target-positive CTC enumeration
in metastasis was higher than that in non-metastasis (p < 0.01), and the quantitation of positive exosomes was correlated
with CRC patients (p < 0.0001). Moreover, the
MAB-W3-3G-based simultaneous detection of CTCs and exosomes was proven
to have the potential for more precise clinical diagnosis. In conclusion,
MAB-W3-3G could detect CTCs and exosomes in the blood samples of tumor
patients with simple manipulation, rapid analysis, and high specificity,
providing an effective liquid biopsy tool for the prediction of CRC.