Optimizing cisplatin delivery to triple-negative breast cancer through novel EGFR aptamer-conjugated polymeric nanovectors

Abstract

Background Management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and limited targeted treatment options. Cisplatin represents a promising chemotherapeutic compound in neoadjuvant approaches and in the metastatic setting, but its use is limited by scarce bioavailability, severe systemic side effects and drug resistance. Novel site-directed aptamer-based nanotherapeutics have the potential to overcome obstacles of chemotherapy. In this study we investigated the tumor targeting and the anti-tumorigenic effectiveness of novel cisplatin-loaded and aptamer-decorated nanosystems in TNBC. Methods Nanotechnological procedures were applied to entrap cisplatin at high efficacy into polymeric nanoparticles (PNPs) that were conjugated on their surface with the epidermal growth factor receptor (EGFR) selective and cell-internalizing CL4 aptamer to improve targeted therapy. Internalization into TNBC MDA-MB-231 and BT-549 cells of aptamer-decorated PNPs, loaded with BODIPY505-515, was monitored by confocal microscopy using EGFR-depleted cells as negative control. Tumor targeting and biodistribution was evaluated by fluorescence reflectance imaging upon intravenously injection of Cyanine7-labeled nanovectors in nude mice bearing subcutaneous MDA-MB-231 tumors. Cytotoxicity of cisplatin-loaded PNPs toward TNBC cells was evaluated by MTT assay and the antitumor effect was assessed by tumor growth experiments in vivo and ex vivo analyses. Results We demonstrate specific, high and rapid uptake into EGFR-positive TNBC cells of CL4-conjugated fluorescent PNPs which, when loaded with cisplatin, resulted considerably more cytotoxic than the free drug and nanovectors either unconjugated or conjugated with a scrambled aptamer. Importantly, animal studies showed that the CL4-equipped PNPs achieve significantly higher tumor targeting efficiency and enhanced therapeutic effects, without any signs of systemic toxicity, compared with free cisplatin and untargeted PNPs. Conclusions Our study proposes novel and safe drug-loaded targeted nanosystems for EGFR-positive TNBC with excellent potential for the application in cancer diagnosis and therapy.

Selective Photo-Assisted Eradication of Triple-Negative Breast Cancer Cells through Aptamer Decoration of Doped Conjugated Polymer Nanoparticles

“…Then, cells were incubated with conjugated wheat germ agglutinin (WGA) Alexa Fluor 647 (Invitrogen, Carlsbad, CA, USA) for 20 min at RT and washed three times with DPBS. Finally, nuclei were stained with 1.5 µM 4′,6-diamidino-2-phenylindole (DAPI, D9542, Sigma-Aldrich) in DPBS for 5 min and coverslips were mounted with glycerol/DPBS over slides [ 27 ]. For internalization experiments, MDA-MB-231/cis cells were incubated with LysoTracker Red DND-99 1:1,000 (Invitrogen, Carlsbad, CA, USA) in RPMI-1640 medium supplemented with 10% FBS previous CPN incubation.…”

“…The exquisite selectivity of oligonucleotide aptamers for cancer cell targeting and their ability to actively internalize into target cells via receptor-mediated endocytosis [ 26 ] make these biomolecules excellent candidates to improve the cancer cell labelling capacity and PDT efficacy. We recently used the anti-EGFR CL4 aptamer [ 27 ] to confer tumor-targeting properties to cisplatin-loaded polymeric nanoparticles, which were used to treat mice bearing TNBC xenografts, thus overcoming the poor bioavailability of the drug [ 27 ]. Furthermore, a group of anti-TNBC nuclease-resistant RNA aptamers were generated by cell-SELEX and were shown to bind with high affinity and specificity to cell-surface receptors unique to TNBC cells [ 28 ].…”

Actively Targeted Nanomedicines in Breast Cancer: From Pre-Clinal Investigation to Clinic

“…This higher efficacy can be related to EGFR-1-mediated internalization, as in MDA-MB-231 depleted from EGFR-1, both nanoparticles exhibited a similar cytotoxic effect with IC 50 values of around 10 µm. This was also corroborated in vivo, as a higher tumor accumulation and a higher tumor growth inhibition were detected with targeted nanoparticles, suggesting the potential EGFR-1 ligand to improve conventional chemotherapy in TNBC [ 180 ]. An improvement in paclitaxel activity was also appreciated in in vivo models of MDA-MB-468-derived tumors in mice.…”

Profiling Cancer Cells by Cell-SELEX: Use of Aptamers for Discovery of Actionable Biomarkers and Therapeutic Applications Thereof

“…More recently, we synthesized cisplatin-loaded poly(lactic-co-glycolic)-block-poly ethylene glycol (PLGA-b-PEG)-based polymeric nanoparticles (PNPs), capable of specifically guiding the chemotherapeutic agent to TNBC xenografts in mice, thanks to the EGFR aptamer that decorates the nanoparticle's surface (Figure 3D). Notably, the CL4-equipped nanovectors showed significantly higher tumor targeting and anticancer activity than naked cisplatin and untargeted nanoparticles, and were also well tolerated with no signs of systemic toxicity [114].…”