Breast Cancer Cells Imaging By Targeting Methionine Transporters with Gadolinium-Based Nanoprobe

The Role of Amino Acids in the Diagnosis, Risk Assessment, and Treatment of Breast Cancer: A Review

This review summarizes the role of amino acids in the diagnosis, risk assessment, imaging, and treatment of breast cancer. It was shown that the content of individual amino acids changes in breast cancer by an average of 10-15% compared with healthy controls. For some amino acids (Thr, Arg, Met, and Ser), an increase in concentration is more often observed in breast cancer, and for others, a decrease is observed (Asp, Pro, Trp, and His). The accuracy of diagnostics using individual amino acids is low and increases when a number of amino acids are combined with each other or with other metabolites. Gln/Glu, Asp, Arg, Leu/Ile, Lys, and Orn have the greatest significance in assessing the risk of breast cancer. The variability in the amino acid composition of biological fluids was shown to depend on the breast cancer phenotype, as well as the age, race, and menopausal status of patients. In general, the analysis of changes in the amino acid metabolism in breast cancer is a promising strategy not only for diagnosis, but also for developing new therapeutic agents, monitoring the treatment process, correcting complications after treatment, and evaluating survival rates.

Amino acid-modified PAMAM dendritic nanocarriers as effective chemotherapeutic drug vehicles in cancer treatment: a study using zebrafish as a cancer model

The use of nanomaterials for drug delivery offers many advantages including the targeted delivery of drugs and their controlled release. Nonetheless, entry into the target cells remains a challenge for many nanomaterials used for drug delivery. Moreover, cellular uptake limits the therapeutic efficiency of many anticancer drugs. An important goal is to increase the specific accumulation of these nanoparticles (NPs) at the desired cancerous tissues. Notably, cancer cells show a high demand for some amino acids and we have used this knowledge to develop novel carrier systems. In this study, drug carriers were produced by the conjugation of multiple amino acids such as l-histidine (H) and l-cysteine (C) or single amino acids such as only H with the G4.5 dendrimers (G) to produce GHC aggregates and GH NP carriers, respectively. Doxorubicin was loaded into the G4.5, GH, and GHC dendrimers (G/DOX, GH/DOX and GHC/DOX, respectively) and the release mechanism was demonstrated at pH 7.4 and pH 5.0. GH/DOX and GHC/DOX showed better stability under physiological conditions than the dendrimer alone (G/DOX). GH/DOX and GHC/DOX exhibited higher inhibition of HeLa cell proliferation in in vitro and in vivo studies in zebrafish, confirming the early release of DOX by disrupting the endosomal membrane and triggering the destabilization of carriers at a lower pH of 5.0.

Magnetic And pH Dual-Responsive Nanoparticles For Synergistic Drug-Resistant Breast Cancer Chemo/Photodynamic Therapy

BACKGROUND

Drug resistance is one of the prime reasons of chemotherapy failure in breast cancer and is also an important factor affecting prognosis.

PURPOSE

In this study, we constructed a functional magnetic mesoporous silica-based nanocomposite (MMSN) for breast cancer chemotherapy/photodynamic therapy.

METHODS

MMSN was characterized by scanning electron microscopy and transmission electron microscopy to observe the morphology. The size distribution and zeta potential of the MSNs were determined using Malvern Particle Size Analyzer. Anti-tumor activity in vitro was investigated by CCK-8 assay, flow cytometry and transwell experiment, and the anti-tumor activity in vivo was probed into by magnetic targeting, toxicity, and antitumor effects in breast cancer-bearing BABL/c nude mice.

RESULTS

The results showed that the release of doxorubicin in the nanocomposites was pH sensitive, and the cumulative release rate reached 80.53% at 60 h under acidic conditions. The nanocomposites had a high cellular uptake ability in MCF-7/ADR cells, and the IC50 value of the nanocomposites on MCF-7/ADR cells was 4.23 μg/mL, much smaller than that of free DOX (363.2 μg/mL). The nanocomposites could effectively reverse resistance and induce apoptosis of MCF-7/ADR cells. The blood biochemistry parameters and H&E staining results showed no serious adverse effects after treatment with the nanocomposites. Prussian blue staining showed that the nanocomposites were able to target tumor tissues in tumor-bearing mice under a magnetic field. The combined chemical/photodynamic therapy significantly inhibited tumor growth in vivo.

CONCLUSION

Nanocomposites with magnetic and pH dual-responsive performance has shown a promising platform for enhanced drug-resistant breast cancer treatment.

Acute Toxicity Evaluation of Glycosylated Gd3+-Based Silica Nanoprobe

PURPOSE

Early stage diseases diagnosed using magnetic resonance imaging (MRI) techniques is of high global interest as a potent noninvasive modality. MRI contrast agents are improved through modifications in structural and physicochemical properties of the applied nanoprobes. But, the potential toxic effects of nanoprobes upon exposure to biological systems are still a major concern.

PROCEDURE

In this study, the acute toxicity of glycosylated Gd³⁺-based silica mesoporous nanospheres (GSNs) as a MRI contrast agent was evaluated in Balb/c mice. In order to evaluate in vivo toxicity of GSN, preclinical studies, daily weight monitoring, hematological/blood chemistry tests, and histological assessment were conducted. Magnetic resonance relaxivities of GSN was determined using a MRI scanner.

RESULTS

The obtained results suggest that in vivo toxicity of GSN was mostly influenced by nanoparticle surface area, functionality, and nanoparticle zeta potential. The maximum tolerated dose (MTD) increased in the following order: mesoporous silica nanospheres (MSNs) at 1 mg/mice < GSN (aspect ratio 1, 2, 8) at 40 mg/mice. The results also indicate GSN, one of the best cell imaging contrast agent, which does not show any significant toxicity on multiple vital organs following injection of 20 mg/mice, while a significant T₁-weighted enhancement was observed in whole body of a Balb/c mice 15 min postinjection of (5 μmol/kg) of body weight of GSN.

CONCLUSIONS

These results shed light on the functionality of MSNs to minimize in vivo toxicity. Also, glyconanoprobe can be beneficially used for nanomedicine and cellular imaging applications without any significant toxicity.

Synthesis, Stability and Relaxivity of TEEPO-Met: An Organic Radical as a Potential Tumour Targeting Contrast Agent for Magnetic Resonance Imaging

Cancer is a widespread and life-threatening disease and its early-stage diagnosis is vital. One of the most effective, non-invasive tools in medical diagnostics is magnetic resonance imaging (MRI) with the aid of contrast agents. Contrast agents that are currently in clinical use contain metals, causing some restrictions in their use. Also, these contrast agents are mainly non-specific without any tissue targeting capabilities. Subsequently, the interest has notably increased in the research of organic, metal-free contrast agents. This study presents a new, stable organic radical, TEEPO-Met, where a radical moiety 2,2,6,6-tetraethylpiperidinoxide (TEEPO) is attached to an amino acid, methionine (Met), as a potentially tumour-targeting moiety. We describe the synthesis, stability assessment with electron paramagnetic resonance (EPR) spectroscopy and relaxation enhancement abilities by an in vitro nuclear magnetic resonance (NMR) and phantom MRI studies of TEEPO-Met. The new compound proved to be stable notably longer than the average imaging time in conditions mimicking a biological matrix. Also, it significantly reduced the relaxation times of water, making it a promising candidate as a novel tumour targeting contrast agent for MRI.

Mesoporous silica nanoparticles functionalized with folic acid/methionine for active targeted delivery of docetaxel

Mesoporous silica nanoparticles (MSNs) are known as carriers with high loading capacity and large functionalizable surface area for target-directed delivery. In this study, a series of docetaxel-loaded folic acid- or methionine-functionalized mesoporous silica nanoparticles (DTX/MSN-FA or DTX/MSN-Met) with large pores and amine groups at inner pore surface properties were prepared. The results showed that the MSNs were successfully synthesized, having good pay load and pH-sensitive drug release kinetics. The cellular investigation on MCF-7 cells showed better performance of cytotoxicity and cell apoptosis and an increase in cellular uptake of targeted nanoparticles. In vivo fluorescent imaging on healthy BALB/c mice proved that bare MSN-NH2 are mostly accumulated in the liver but MSN-FA or MSN-Met are more concentrated in the kidney. Importantly, ex vivo fluorescent images of tumor-induced BALB/c mice organs revealed the ability of MSN-FA to reach the tumor tissues. In conclusion, DTX/MSNs exhibited a good anticancer activity and enhanced the possibility of targeted drug delivery for breast cancer.