O22: CONJUGATED IRON NANOPARTICLES AS THERAPEUTIC CARRIERS FOR SPECIFIC TARGETING OF CANCER CELLS

Abstract

Abstract Introduction Precision medicine with minimal side effects remains the goal of cancer therapy. Iron oxide nanoparticles are non-toxic, successful carriers of substances, targeting tissues and delivering high payloads of conjugated agents. Interfering RNA (siRNA) disrupts protein expression, an effective treatment e.g. for hereditary amyloidosis. This study tested transferrin-conjugated dopamine-coated iron oxide nanoparticle (TF-dpFe3O4) delivery of siRNA to cells overexpressing transferrin receptor (TFR). Method Cells were cultured in FBS-DMEM/F12. Fe3O4 nanoparticles were prepared by co-precipitation, dopamine coated +/- transferrin conjugation. LDH/MTT assays assessed cell viability responses to [TF-dpFe3O4] or [dpFe3O4]. Protein expression was examined by PAGE, densitometry and immunofluorescence. Targeting efficacy was determined by MEK2 gene silencing using siRNA-conjugated TF-dpFe3O4 or dpFe3O4. Result T-47D cells expressed high levels of TFR and MEK2. No significant effect on cell viability was observed with ≤2.5mg/mL TF-dpFe3O4 or dpFe3O4. By conventional transfection, 10nM siRNA lowered MEK2 expression levels to 25% (48hr); levels rebounded to 50% by 72hr. 10nM siRNA-conjugated TF-dpFe3O4 (2.5mg/mL) reduced MEK2 expression by 50% (72hr) without rebound; expression of a-tubulin (control) was unaffected. In contrast, as MEK2 levels decreased, TFR levels increased 2.2-fold (72hrs). Conclusion TF-dpFe3O4 nanoparticles are safe/efficient vehicles for delivering siRNA to cancer cells over-expressing TFR. Over 72hrs, protein expression of MEK2 reduced by 50%, a target superior to conventional methods. Notably: as the MAPK pathway was inhibited, increases in TFR levels were observed, suggesting adaptations to damage or stress. Take-home message TF-dpFe3O4 nanoparticles are a safe and efficient vehicle for delivering siRNA to cancer cells over-expressing TFR, allowing for successful targeting and inhibition of MAPK pathway proteins, such as MEK2, that drive tumour growth.