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Original Research

Apoptosis-promoting effect of rituximab-conjugated magnetic nanoprobes on malignant lymphoma cells with CD20 overexpression

, , , , , , , & show all
Pages 921-936 | Published online: 01 Feb 2019
 

Abstract

Background

Cancer targeting nanoprobes with precisely designed physicochemical properties may show enhanced pharmacological targeting and therapeutic efficacy. As a widely used commercialized antibody, rituximab has been in clinical use for three decades and has lengthened or even saved thousands of lives. However, many people cannot benefit from rituximab treatment because of drug resistance or side effects.

Methods

In this study, a 13-nm rituximab-conjugated magnetic nanoparticle was developed as a therapeutic nanoprobe targeting CD20 overexpressing malignant lymphoma cells to enhance the treatment effects of rituximab. The magnetic cores (2,3-dimercaptosuccinicacid modified Fe3O4 nanoparticles, Fe3O4@DMSA) of the nanoprobes with an average diameter of 6.5 nm were synthesized using a co-precipitation method. Rituximab was then conjugated on the surface of Fe3O4@DMSA using a cross-linking agent (carbodiimide/N-hydroxysulfosuccinimide sodium salt). Based on theoretical calculations, approximately one antibody was coupled with one nanoparticle, excluding the multivalent antibody effect.

Results

Cell targeting experiments and magnetic resonance (MR) signal and T2 measurements showed that the Fe3O4@DMSA@Ab nanoprobes have specific binding affinity for CD20-positive cells. Compared to rituximab and Fe3O4@DMSA, Fe3O4@DMSA@Ab nanoprobes significantly reduced cell viability and promoted Raji cell apoptosis. Initiating events of apoptosis, including increased intracellular calcium and reactive oxygen species, were observed in nanoprobe-treated Raji cells. Nanoprobe-treated Raji cells also showed the most drastic decrease in mitochondrial membrane potential and Bcl-2 expression, compared to rituximab and Fe3O4@DMSA-treated Raji cells.

Conclusion

These results indicate that Fe3O4@DMSA@Ab nanoprobes have the potential to serve as MRI tracers and therapeutic agents for CD20-positive cells.

Acknowledgments

This research was supported by the National Key Research and Development Program of China (No 2017YFA0205502), the National Basic Research Program of China (973 program No 2013CB733800), National Natural Science Foundation of China (No 81571806, 81671820, 81771899), the Jiangsu Provincial Special Program of Medical Science (BL2013029), and the Fundamental Research Funds for the Central Universities.

Disclosure

The authors report no conflicts of interest in this work.