Krebs Cycle Intermediate-Modified Carbonate Apatite Nanoparticles Drastically Reduce Mouse Tumor Burden and Toxicity by Restricting Broad Tissue Distribution of Anticancer Drugs

Mitigating off-target distribution and enhancing cytotoxicity in breast cancer cells with alpha-ketoglutaric acid-modified Fe/Mg-CA nanoparticles

Purpose

In this work, pH-sensitive alpha-ketoglutaric acid-modified Fe/Mg-carbonate apatite (α-KAM-Fe/Mg-CA) NPs were introduced and found to be capable of promoting the selective delivery of cancer-killing drug doxorubicin (DOX) in breast cancer cells, while simultaneously mitigating DOX toxicity on normal cells.

Methods

As part of the characterization and evaluation of α-KAM-Fe/Mg-CA NPs to target breast cancer cells, a series of assessments were performed, which included size measurements, morphological analysis, FTIR, cytotoxicity assessment, hemolysis, drug binding, cellular uptake, and pH-responsive drug release tests. Liquid chromatography-mass spectrometry was used to conduct the protein corona analysis of α-KAM-Fe/Mg-CA using 10% FBS (fetal bovine serum) and mice plasma. Furthermore, to investigate the distribution of DOX-loaded α-KAM-Fe/Mg-CA NPs in major tissues and the tumor, a biodistribution investigation was conducted in mammary tumor-induced Balb/c mouse models 24 h after the intravenous administration of DOX-loaded α-KAM-Fe/Mg-CA NPs.

Results

The in vitro pH-dependent release of DOX over time demonstrated that α-KAM-Fe/Mg-CA NPs were pH-responsive and degraded rapidly at acidic pH levels. When compared to free DOX, the DOX-loaded α-KAM-Fe/Mg-CA NPs demonstrated a potent antiproliferative effect on breast cancer cells. Confocal microscopy confirmed the effective internalization of DOX-loaded α-KAM-Fe/Mg-CA NPs in breast cancer cells. The protein corona analysis revealed an affinity for dysopsonins (serum albumin, apolipoproteins) and transport proteins that may assist in extending their blood circulation period. Furthermore, biodistribution data of DOX-loaded α-KAM-Fe/Mg-CA NPs in the mammary tumor-induced Balb/c mouse model indicated extended circulation in the bloodstream, reduced non-target distribution in major tissues, and increased drug accumulation in the tumor.

Conclusion

The results obtained suggest that α-KAM-Fe/Mg-CA NPs may emerge as a prospective candidate for delivering therapeutic cargos to treat malignant mammary tumors.

Silicon-Gold Nanoparticles Affect Wharton's Jelly Phenotype and Secretome during Tri-Lineage Differentiation

Multiple studies have demonstrated that various nanoparticles (NPs) stimulate osteogenic differentiation of mesenchymal stem cells (MSCs) and inhibit adipogenic ones. The mechanisms of these effects are not determined. The aim of this paper was to estimate Wharton’s Jelly MSCs phenotype and humoral factor production during tri-lineage differentiation per se and in the presence of silicon–gold NPs. Silicon (SiNPs), gold (AuNPs), and 10% Au-doped Si nanoparticles (SiAuNPs) were synthesized by laser ablation, characterized, and studied in MSC cultures before and during differentiation. Humoral factor production (n = 41) was analyzed by Luminex technology. NPs were nontoxic, did not induce ROS production, and stimulated G-CSF, GM-CSF, VEGF, CXCL1 (GRO) production in four day MSC cultures. During MSC differentiation, all NPs stimulated CD13 and CD90 expression in osteogenic cultures. MSC differentiation resulted in a decrease in multiple humoral factor production to day 14 of incubation. NPs did not significantly affect the production in chondrogenic cultures and stimulated it in both osteogenic and adipogenic ones. The major difference in the protein production between osteogenic and adipogenic MSC cultures in the presence of NPs was VEGF level, which was unaffected in osteogenic cells and 4–9 times increased in adipogenic ones. The effects of NPs decreased in a row AuNPs > SiAuNPs > SiNPs. Taken collectively, high expression of CD13 and CD90 by MSCs and critical level of VEGF production can, at least, partially explain the stimulatory effect of NPs on MSC osteogenic differentiation.

Carbonate Apatite and Hydroxyapatite Formulated with Minimal Ingredients to Deliver SiRNA into Breast Cancer Cells In Vitro and In Vivo

Introduction: Cancer is one of the top-ranked noncommunicable diseases causing deaths to nine million people and affecting almost double worldwide in 2018. Tremendous advancement in surgery, chemotherapy, radiation and targeted immunotherapy have improved the rate of cure and disease-free survival. As genetic mutations vary in different cancers, potential of customized treatment to silence the problem gene/s at the translational level is being explored too. Yet delivering therapeutics at the required dosage only to the affected cells without affecting the healthy ones, is a big hurdle to be overcome. Scientists worldwide have been working to invent a smart drug delivery system for targeted delivery of therapeutics to tumor tissues only. As part of such an effort, few organic nanocarriers went to clinical trials, while inorganic nanoparticles (NPs) are still in development stage despite their many customizable properties. Carbonate apatite (CA), a pH sensitive nanocarrier has emerged as an efficient delivery system for drugs, plasmids and siRNAs in preclinical models of breast and colon cancers. Like hydroxyapatite (HA) which serves as a classical tool for delivery of genetic materials such as siRNA and plasmid, CA is an apatite-based synthetic carrier. We developed simplified methods of formulating CA-in-DMEM and a DMEM-mimicking buffer and HA in a HEPES-buffered solution and characterized them in terms of size, stability, protein corona (PC) composition, cytotoxicity, siRNA delivery efficiency in breast cancer cells and siRNA biodistribution profile in a mouse model of breast cancer. Methods: Particle growth was analyzed via spectrophotometry and light microscopy, size was measured via dynamic light scattering and scanning electron microscopy and confirmation of functional groups in apatite structures was made by FT-IR. siRNA-binding was analyzed via spectrophotometry. Stability of the formulation solutions/buffers was tested over various time points and at different temperatures to determine their compatibility in the context of practical usage. Cellular uptake was studied via fluorescence microscopy. MTT assay was performed to measure the cytotoxicity of the NPs. Liquid chromatography—mass spectrometry was carried out to analyze the PC formed around all three different NPs in serum-containing media. To explore biodistribution of all the formulations, fluorescence-labeled siRNA-loaded NPs were administered intravenously prior to analysis of fluorescence intensity in the collected organs and tumors of the treated mice. Results: The size of NPs in 10% serum-containing media was dramatically different where CA-in-DMB and HA were much larger than CA-in-DMEM. Effect of media was notable on the PC composition of all three NPs. All three NPs bound albumin and some common protease inhibitors involved in bone metabolism due to their compositional similarity to our bone materials. Moreover, CA also bound heme-binding proteins and opsonins. Unlike CA, HA bound different kinds of keratins. Difference in PC constitution was likely to influence accumulation of NPs in various organs including those of reticuloendothelial system, such as liver and spleen and the tumor. We found 10 times more tumor accumulation of CA-in-DMB than CA-in-DMEM, which could be due to more stable siRNA-binding and distinct PC composition of the former. Conclusion: As a nanocarrier CA is more efficient than HA for siRNA delivery to the tumor. CA prepared in a buffer containing only the mere constituents was potentially more efficient than classical CA prepared in DMEM, owing to the exclusion of interference attributed by the inorganic ions and organic molecules present in DMEM.