Related Experiment Video
Updated: May 7, 2025
A Flow Cytometry-Based Cell Surface Protein Binding Assay for Assessing Selectivity and Specificity of an Anticancer Aptamer
Published on: September 13, 2022
Development of dual aptamers-functionalized c-MET PROTAC degraders for targeted therapy of osteosarcoma
Xuekun Fu1, Jie Huang1,2, Xinxin Chen1
1Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
Abstract:
Rationale: Osteosarcoma (OS) is the most common bone malignancy. c-MET is recognized as a therapeutic target. However, traditional c-MET inhibitors show compromised efficacy due to the acquired resistance and side effects. PROTACs targeting c-MET have displayed improved antitumor efficacy by overcoming drug resistance, whereas safety concern caused by lack of tumor-targeting ability is still a pending issue. AS1411 is an aptamer that recognizes and penetrates tumors by targeting nucleolin (NCL) overexpressed on the surface of tumor cells. Since NCL interacts with an E3 ligase MDM2 intracellularly, we repurposed AS1411 as an MDM2 recruiter by employing NCL as a bridge. Methods: We select the ssDNA c-MET aptamer SL1 as the c-MET ligand to design dual aptamer-functionalized PROTACs, as SL1 can be easily conjugated to AS1411 through base-pair complementarity using a nucleic acid linker. Four AS1411-SL1 chimeras are generated by linking AS1411 to either the 5' or 3' terminus of SL1 via two different lengths of nucleic acid linkers. The therapeutic efficacy of these PROTACs is evaluated through both in vitro and in vivo experiments. Results: The PROTACs enable the ubiquitination and degradation of c-MET. The PROTACs effectively inhibit growth, enhance apoptosis, and overcome drug resistance of OS cells in vitro. The PROTACs demonstrate in vivo tumor-targeting ability and facilitate the OS treatment with no detectable toxicity. Conclusion: This study suggests that the AS1411-SL1 chimeras could be promising c-MET degraders for targeted therapy of OS.
Insights
New PROTACs (proteolysis-targeting chimeras) effectively degrade c-MET in osteosarcoma. These novel aptamer-functionalized molecules show potent tumor targeting and anti-cancer effects with minimal toxicity.
Area of Science:
- Biomedical Engineering
- Oncology
- Molecular Biology
Background:
- Osteosarcoma (OS) is a prevalent bone cancer with limited treatment options.
- c-MET is a key therapeutic target, but conventional inhibitors face resistance and side effects.
- Existing Proteolysis-Targeting Chimeras (PROTACs) show promise but lack tumor specificity.
Purpose of the Study:
- To develop novel dual aptamer-functionalized PROTACs for targeted c-MET degradation in osteosarcoma.
- To leverage the AS1411 aptamer for tumor targeting and the SL1 aptamer for c-MET binding.
- To investigate the therapeutic potential and safety of these novel constructs.
Main Methods:
- Designed and synthesized four AS1411-SL1 chimera PROTACs with varying linker strategies.
- Evaluated PROTACs' ability to induce c-MET ubiquitination and degradation.
- Assessed *in vitro* efficacy (growth inhibition, apoptosis, drug resistance) and *in vivo* therapeutic effects and toxicity.
Main Results:
- The AS1411-SL1 PROTACs successfully induced c-MET degradation in osteosarcoma cells.
- PROTACs demonstrated significant *in vitro* inhibition of OS cell growth and enhanced apoptosis.
- *In vivo* studies confirmed tumor-targeting capability and effective OS treatment with no observable toxicity.
Conclusions:
- AS1411-SL1 chimeras represent a promising new class of c-MET degraders.
- These novel PROTACs offer targeted therapy potential for osteosarcoma.
- The dual aptamer strategy enhances efficacy and safety for osteosarcoma treatment.
