5th March 2019
Hepatocellular carcinoma (HCC) is a common malignant cancer. Glypican-3 (GPC3), a cellular membrane proteoglycan, is highly expressed in more than 70% of HCC patients and therefore may be an ideal biomarker for in vivo HCC diagnosis and imaging. Antibody reagents have limitations such as immunogenicity, easy degradation, and high cellular cytotoxicity effect in vivo so aptamers are an ideal substitute.
Selection of specific aptamers to GPC3 was achieved in multiple rounds of capillary electrophoresis-SELEX (CE-SELEX) with 19 clones identified. Fluorescent microscopy showed clear presence of GPC3 in Huh7 and PLC/PRF/5 (GPC3-positive cell lines) and not L02 or A549, two GPC3-negative cell lines.
Additional experiments also showed that fluorescently modified aptamers also worked as flow cytometry regents binding specifically to Huh7 cells. A truncated version of one specific aptamer APS613-1 demonstrated higher GPC3-binding affinity than the original APS613 clone, this was also further improved with chemical modifications. This was then followed up with tissue staining use the highest affinity aptamer APS613-1, the tissue staining showed clear localisation to the subcutaneous cancer tissue and similar localising with an anti-GPC3 antibody.
Results also showed the aptamer was a suitable in vivo agent, showing stability and specificity to GPC3-positive HCC cells up to 4 hours to xenograft tumors in nude mice.
Aptamer Group has also successfully selected cell based biomarkers, and also delivers minimal fragment OptimersTM for improved binding over standard aptamers. Modified bases can also be included if desired for stability. If you would like more information on aptamers for your research contact us using the form below.
Dong, L., Zhou, H., Zhao, M., Gao, X., Liu, Y., Liu, D., Guo, W., Hu, H., Xie, Q., Fan, J., Lin, J., Wu, W. (2019). Phosphorothioate-Modified AP613-1 Specifically Targets GPC3 when Used for Hepatocellular Carcinoma Cell Imaging. Molecular Therapy – Nucleic Acids. 2018 Dec 7; 13: 376–386