EGF receptor targeted tumor imaging with biotin-PEG-EGF linked to 99mTc-HYNIC labeled avidin and streptavidin

Size-adaptable and ligand (biotin)-sheddable nanocarriers equipped with avidin scavenging technology for deep tumor penetration and reduced toxicity

The conventional active-targeting nano-chemotherapy suffers from poor tumor tissue penetration and non-negligible toxicity due to the size/ligand dilemmas and insufficient target selectivity. In this report, a stimuli-responsive size-adaptable and ligand (biotin)-sheddable drug delivery system (DDS) combined with two-step strategy of biotin-avidin system was designed to seek a balance between tumor targeting and penetration as well as to self-scavenge the nonresponsive nanocarriers in normal tissues. This DDS was composed of 'multi-seed' polymeric liposomes (ASL-BIO-MPL) with asulacrine-loaded micelles as seeds in their aqueous cavities. The shell of such liposomes was modified with MMP-9 cleavable polymer-polypeptide functionalized with the tumor targeting ligand biotin. ASL-BIO-MPL could disintegrate into mixture of irregularly-shaped liposomes (~200 nm) and scattered tiny micelles (~40 nm) after incubation with MMP-9. The fluorescence-labeled BIO-MPL could travel to the center of the 4T1 breast tumor spheroids under the action of MMP-9, possibly benefited from the relay of released tiny micelles. Conversely, neither the biotin-modified micelles nor non-MMP-9-responsive multi-seed liposomes could penetrate into the spheroids possibly due to the potent binding-site barrier of biotin and large size, respectively. In tumor-bearing mice, ASL-BIO-MPL exhibited the strongest drug penetrability and thus the optimal inhibition of tumor growth compared to other formulations. Following administration of avidin with a rational dosage regimen, the number of apoptotic cells in normal tissues induced by ASL-BIO-MPL reduced without affecting their targeting effect, suggesting the followed administration of adivin could scavenge the DDS in non-target site. Overall, the size/ligand adapting MPL system combined with two-step strategy of biotin-avidin may provide potential avenues for nanocarriers to enhance deep tumor tissue targeting and protect normal tissues.

pH-sensitive doxorubicin-loaded polymeric nanocomplex based on β-cyclodextrin for liver cancer-targeted therapy

BACKGROUND

Doxorubicin (DOX) is one of the most effective treatments for hepatocellular carcinoma (HCC), but is restricted by its poor pharmacokinetics. Herein, we exploited efficient targeted drug delivery systems and they have been found to be a worthy strategy for liver cancer therapy.

MATERIALS AND METHODS

We investigated polymeric nanoparticles which were synthesized based on host-guest interaction between β-cyclodextrin and benzimidazole. The properties of nanoparticles with regard to size/shape, encapsulation efficiency, and drug release were investigated using conventional experiments. Cell proliferation assay in vitro, cell uptake assay, and cell apoptosis analysis were used to investigate cytotoxicity, uptake, and mechanism of targeted supramolecular prodrug complexes (TSPCs)-based self-assemblies and supramolecular prodrug complexes (SPCs)-based self-assemblies.

RESULTS

The pH-sensitive lactobionic acid (LA)-modified pH-sensitive self-assemblies were synthesized successfully. The results of in vitro released assay showed that the accelerated released of DOX from TSPCs-based self-assemblies with the decrease of pH value. When TSPCs-based self-assemblies were taken up by HepG2 cells, they demonstrated a faster release rate under acidic conditions and proved to have higher cytotoxicity than in the presence of LA. A mechanistic study revealed that TSPCs-based self-assemblies inhibited liver cell proliferation by inducing cell apoptosis.

CONCLUSION

The pH-sensitive nanocomplex, as liver-targeted nanoparticles, facilitated the efficacy of DOX in HepG2 cells, offering an appealing strategy for the treatment of HCC.

Synthesis of Two-Photon Active Tricomponent Fluorescent Probe for Distinguishment of Biotin Receptor Positive and Negative Cells and Imaging 3D-Spheroid

A fluorescence microscopy-based distinguishment between biotin receptor (BiR) positive and negative cell lines via receptor-mediated endocytosis has been demonstrated. A water-soluble, three-component, two-photon (2P) active solvatofluorochromic probe has been designed and synthesized. The applicability of the probe for 2P microscopy and 3D-spheroid was also assessed.

Targeted therapy of triple negative MDA-MB-468 breast cancer with curcumin delivered by epidermal growth factor-conjugated phospholipid nanoparticles

Triple-negative breast cancer (TNBC) is associated with poor survival as chemotherapy is currently limited to conventional cytotoxic agents. Curcumin has promising anticancer actions against TNBC, but its application is hindered by poor bioavailability and rapid degradation in vivo. In the present study, curcumin-loaded phospholipid nanoparticles (Cur-NPs) conjugated with epidermal growth factor (EGF) were prepared for specific targeting of EGF receptors overexpressed in TNBC. NP formulation was performed by reacting EGF peptide with N-hydroxysuccinimide-Polyethylene Glycol-1,2-Distearoyl-sn-Glycero-3-Phosphoethanolamine (NHS-PEG₁₀₀₀₀-DSPE), followed by efficient curcumin loading through lipid film hydration. EGF conjugation did not significantly affect NP size, zeta potential or morphology. Specific targeting was confirmed by EGF receptor activation and blocking of ¹²⁵I-labeled NP binding by excess EGF. EGF-Cur-NP dose-dependently suppressed MDA-MB-468 TNBC cell survival (IC50, 620 nM), and completely abolished their capacity to form colonies. The cytotoxic effects were more potent compared with those of free curcumin or Cur-NP. In mice bearing MDA-MB-468 tumors, injections of 10 mg/kg EGF-Cur-NP caused a 59.1% retardation of tumor growth at 3 weeks compared with empty NP, whereas the antitumor effect of Cur-NP was weak. These results indicate that EGF-conjugated NHS-PEG₁₀₀₀₀-DSPE phospholipid NPs loaded with curcumin may be useful for treating TNBCs that overexpress the EGF receptor.

Monoclonal antibody-conjugated superparamagnetic iron oxide nanoparticles for imaging of epidermal growth factor receptor-targeted cells and gliomas

The objective of this study was to successfully synthesize epidermal growth factor receptor monoclonal antibody-conjugated superparamagnetic iron oxide nanoparticles (EGFRmAb-SPIONs) and explore their biocompatibility and potential applications as a targeted magnetic resonance imaging (MRI) contrast agent for the EGFR-specific detection of brain glioma in vivo. After conjugation of EGFRmAb with SPIONs, the magnetic characteristics of EGFRmAb-SPIONs were investigated. Thereafter, the targeting abilities of EGFRmAb-SPIONs with MRI were qualitatively and quantitatively assessed in EGFR-positive C6 glioma cells in vitro and in a Wistar rat model bearing C6 glioma in vivo. Furthermore, the preliminary biocompatibility and toxicity of EGFRmAb-SPIONs were evaluated in normal rats through hematology assays and histopathologic analyses. Statistical analysis was performed using one-way analysis of variance and Student t-test, with a significance level of p < .05. From the results of EGFRmAb-SPION characterizations, the average particle size was 10.21 nm and the hydrodynamic diameter was 161.5 ± 2.12 nm. The saturation magnetization was 55 emu/g·Fe, and T2 relaxivity was 92.73 s-1mM-1 in distilled water. The preferential accumulation of the EGFRmAb-SPIONs within glioma and subsequent MRI contrast enhancement were demonstrated both in vitro in C6 cells and in vivo in rats bearing C6 glioma. After intravenous administration of EGFRmAb-SPIONs, T2-weighted MRI of the rat model with brain glioma exhibited an apparent hypointense region within glioma from 2 to 48 hours. The maximal image contrast was reached at 24 hours, where the signal intensity decreased and the R2 value increased by 30% compared to baseline. However, T2-weighted imaging of the rat model administered with SPIONs showed no visible signal changes within the tumor over the same time period. Moreover, no evident toxicities in vitro and in vivo with EGFRmAb-SPIONs were clearly identified based on the laboratory examinations. EGFRmAb-SPIONs could potentially be employed as a targeted contrast agent in the molecule-specific diagnosis of brain glioma in MRI.