ABSTRACT
Esophageal cancer is a common cancer with high morbidity and mortality that severely threatens the safety and quality of human life. The strong metastatic nature of esophageal cancer enables it to metastasize more quickly and covertly, making it difficult for current diagnostic and treatment methods to achieve efficient early screening, as well as timely and effective treatment. As a promising solution, nucleic acid aptamers, a kind of special single-stranded DNA or RNA oligonucleotide selected by the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology, can specifically bind with different molecular targets. In this paper, random DNA single-stranded oligonucleotides were used as the initial library. Using TE-1 cells and HEEC cells as targets, specific binding sequences were selected by 15 rounds of the cell-SELEX method, and the aptamer sequence that binds to TE-1 cells with the most specificity was obtained and named Te4. The Te4 aptamer was further validated for binding specificity, binding affinity, type of target, in vitro cytotoxicity when conjugated with DOX(Te4-DOX), and in vivo distribution. Results of in vitro validation showed that Te4 has outstanding binding specificity with a Kd value of 51.16 ± 5.52 nM, and the target type of Te4 was preliminarily identified as a membrane protein. Furthermore, the cytotoxicity experiment showed that Te4-DOX has specific cytotoxicity towards cultured TE-1 cells. Finally, the results of the in vivo distribution experiment showed that the Te4 aptamer is able to specifically target tumor regions in nude mice, showing great potential to be applied in future diagnosis and targeted therapy of esophageal cancer.
ABSTRACT
Aptamers, a class of oligonucleotides that can bind with molecular targets with high affinity and specificity, have been widely applied in research fields including biosensing, imaging, diagnosing, and therapy of diseases. However, compared with the rapid development in the research fields, the clinical application of aptamers is progressing at a much slower speed, especially in the therapy of cancer. Obstructions including nuclease degradation, renal clearance, a complex selection process, and potential side effects have inhibited the clinical transformation of aptamer-conjugated drugs. To overcome these problems, taking certain measures to improve the biocompatibility and stability of aptamer-conjugated drugs in vivo is necessary. In this review, the obstructions mentioned above are thoroughly discussed and the methods to overcome these problems are introduced in detail. Furthermore, landmark research works and the most recent studies on aptamer-conjugated drugs for cancer therapy are also listed as examples, and the future directions of research for aptamer clinical transformation are discussed.
Subject(s)
Aptamers, Nucleotide , Neoplasms , Humans , Neoplasms/drug therapyABSTRACT
Traction and quantitative detection of trace amount of target cells inside of biochip system in real-time has been a challenge for biomedical and clinical researchers. In this manuscript, we report fabrication of a photoelectrochemical platform that has integrated both biometric recognition and signal acquisition through microfabrication technology. In this chip, a ternary ZnO/CdTe/Bi nanorod array is fabricated, which significantly extends the absorption wavelength from the UV to the visible and even near-infrared regions for both photocarrier generation and surface plasmon resonance, ultimately achieving the amplification of initial photocurrent responses. The artificially designed aptamers with amino groups are assembled on the surface of the outermost Bi nanoparticles, which are used as signal probes due to the specific recognition to the nasopharyngeal carcinoma 5-8F cell. We demonstrate that different concentration of 5-8F cells is captured by aptamers, and the signal changes accordingly with the amount of the cells that have been trapped. As a result, the proposed biochip demonstrates rapid response in a wide linear range of 102-107 cells·mL-1 with the detection limit as low as 32 cells·mL-1 and provides a potential useful model for a variety of biological analysis including clinical point-of-care testing.
