A review of Nucleic acid aptamers in diagnosis of colorectal cancer

A review of Nucleic acid aptamers in diagnosis of colorectal cancer
Javad Yaghmoorian Khojini,^1,* Ali Osmay Gure,²
1. department of cellular and molecular biology and microbiology, Faculty of Biological science and technologies , University of Isfahan, Isfahan, Iran
2. Genetics Department, Faculty of biological science, Tarbiat Modares University
Introduction: Aptamers are relatively small biomolecules (oligonucleotides ranging from 20 to 170 nucleotides or peptides with 12 to 30 amino acid residues) or short sequences of nucleic acid which have a unique three-dimensional structure that is influenced by their sequence and this structure affects the binding of aptamers to theirs specific ligands with High tendency and high specificity. Small size and fast and cheap production process along with high stability, ease of chemical production, simple storage and resistance to denaturation have made them attractive molecules in cancer research fields. Aptamers isolated from large combinatorial libraries through the Systematic Evolution of Ligands by Exponential enrichment (SELEX) procedure. Colorectal cancer (CRC) is one of the most common cancers worldwide with an estimated 1 million people diagnosed annually. In the world, colorectal cancer accounts for 9.5% of cancer rates in men and 10% of this rate in women and this cancer is considered as one of the most important cancers in both sexes. Although the effectiveness of current treatments for colorectal cancer is very low, early detection can help prevent it from growing rapidly in the body. This study Review recent advances in the development of nucleic acid aptamer-based methods for diagnosis and prognosis of colorectal cancer.
Methods: In this study, the method of library collection, search in various texts and authoritative scientific articles has been used.
Results: Nucleic acid aptamers are a class of high-affinity nucleic acid ligands and they can be used in laboratory research and in clinical diagnosis and treatment. Colorectal cancer (CRC) is the most frequently diagnosed cancer which causes many deaths in the world every year. Circulating carcinoembryonic antigen (CEA) is a tumor-associated glycoprotein antigen that has been used in clinical diagnosis and prognosis of CRC and it is first blood biomarker used for CRC detection. There are many studies which have developed aptamer-based diagnostic systems for detection of CEA. Circulating tumor cells (CTCs) are considered to play a key role in metastasis of cancers such as colorectal cancer and some aptamers like SYL3C can play role in isolation of them. MUC1 aptamer is a DNA aptamer specific for mucin-1 and is used for colorectal cancer DLD-1 cells. The PDGF aptamer has high promise to be used as an effective and specific inhibitor of PDGF in cancer therapy. Overexpression of PDGF-BB is associated with the development of colorectal cancer. Fluorescently labeled KCHA10 and KDED2a-3 DNA aptamers that they can also be used to diagnose some colorectal cancer cells. 488-labeled YJ-1 is one of the aptamers for capturing colorectal cancer cells. Fluorescently labeled anti- EpCAM DNA aptamer (SYL3C-CY3) as an effective probe for diagnosis of EpCAM-positive CRC cells in tissue samples derived from patients with CRC. A DNA aptamer named J3 labeled with Cy5 fluorescent dye is an excellent probe for imaging of tissue sections derived from CRC patients. XL-33-1 is also one of the aptamers that has a similar approximation capability to J3 aptemer. Fluorine-18 is one of the aptamers that binds to the extracellular domain of protein tyrosine kinase 7 (PTK7) and PTK7 is a transmembrane protein overexpressed in CRC. 5TR1 aptamer is one of the aptamers for in vivo MR imaging-guided drug delivery in a murine colorectal carcinoma model. There are many other aptamers that can be used to diagnose and treat cancers, especially colorectal cancer and further studies on them can further enhance their value.
Conclusion: Aptamer technology is a tool with new and extraordinary capabilities that help them in the diagnosis and treatment of various diseases, including cancers such as colorectal cancer. This review covers the reported applications of nucleic acid aptamers in the diagnosis of colorectal cancer. Given that many studies have been conducted on the importance of aptamers in the treatment of cancers, especially colorectal cancer, and this shows the importance of their existence. Further researches could shed more light on the importance and benefits of using aptamers in the treatment and diagnosis and prevention of colorectal cancer.
Keywords: CRC, Aptamer technology, Diagnosis