Tumor-preferential sustained drug release enhances antitumor activity of block copolymer micelles

A Robust and Highly Precise Alternative against the Proliferation of Intestinal Carcinoma and Human Hepatocellular Carcinoma Cells Based on Lanthanum Strontium Manganite Nanoparticles

In this report, lanthanum strontium manganite at different Sr²⁺ ion concentrations, as well as Gd³⁺ or Sm³⁺ ion substituted La_0.5-YM_YSr_0.5MnO₃ (M = Gd and Sm, y = 0.2), have been purposefully tailored using a sol gel auto-combustion approach. XRD profiles confirmed the formation of a monoclinic perovskite phase. FE-SEM analysis displayed a spherical-like structure of the La_0.8Sr_0.2MnO₃ and La_0.3Gd_0.2Sr_0.2MnO₃ samples. The particle size of the LSM samples was found to decrease with increased Sr²⁺ ion concentration. For the first time, different LSM concentrations were inspected for their cytotoxic activity against CACO-2 (intestinal carcinoma cells) and HepG-2 (human hepatocellular carcinoma cells). The cell viability for CACO-2 and HepG-2 was assayed and seen to decrease depending on the Sr²⁺ ion concentration. Half maximal inhibitory concentration IC₅₀ of CACO-2 cell and HepG-2 cell inhibition was connected with Sr²⁺ ion ratio. Low IC₅₀ was noticable at low Sr²⁺ ion content. Such results were correlated to the particle size and the morphology. Indeed, the IC₅₀ of CACO-2 cell inhibition by LSM at a strontium content of 0.2 was 5.63 ± 0.42 µg/mL, and the value increased with increased Sr²⁺ ion concentration by up to 0.8 to be = 25 ± 2.7 µg/mL. Meanwhile, the IC₅₀ of HepG-2 cell inhibition by LSM at a strontium content of 0.2 was 6.73 ± 0.4 µg/mL, and the value increased with increased Sr²⁺ ion concentration by up to 0.8 to be 31± 3.1 µg/mL. All LSM samples at different conditions were tested as antimicrobial agents towards fungi, Gram positive bacteria, and Gram negative bacteria. For instance, all LSM samples were found to be active towards Gram negative bacteria Escherichia coli, whereas some samples have presumed antimicrobial effect towards Gram negative bacteria Proteus vulgaris. Such results confirmed that LSM samples possessed cytotoxicity against CACO-2 and HepG-2 cells, and they could be considered to play a substantial role in pharmaceutical and therapeutic applications.

Modeling of Nanotherapy Response as a Function of the Tumor Microenvironment: Focus on Liver Metastasis

The tumor microenvironment (TME) presents a challenging barrier for effective nanotherapy-mediated drug delivery to solid tumors. In particular for tumors less vascularized than the surrounding normal tissue, as in liver metastases, the structure of the organ itself conjures with cancer-specific behavior to impair drug transport and uptake by cancer cells. Cells and elements in the TME of hypovascularized tumors play a key role in the process of delivery and retention of anti-cancer therapeutics by nanocarriers. This brief review describes the drug transport challenges and how they are being addressed with advanced in vitro 3D tissue models as well as with in silico mathematical modeling. This modeling complements network-oriented techniques, which seek to interpret intra-cellular relevant pathways and signal transduction within cells and with their surrounding microenvironment. With a concerted effort integrating experimental observations with computational analyses spanning from the molecular- to the tissue-scale, the goal of effective nanotherapy customized to patient tumor-specific conditions may be finally realized.

Leukemia Inhibitory Factor-Loaded Nanoparticles with Enhanced Cytokine Metabolic Stability and Anti-Inflammatory Activity

PURPOSE

To synthesize and assess the in vitro biological activity of nanoparticles containing leukemia inhibitory factor (LIF). These NanoLIF particles are designed to prolong the neuroprotective and anti-inflammatory actions of LIF in future preclinical studies of ischemic stroke.

METHODS

LIF was packaged in nanoparticles made of poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) polymer to form LIF-loaded nanoparticles (NanoLIF). The surface of NanoLIF was also modified with the CD11b antibody (CD11b-NanoLIF) targeting activated peripheral macrophages to increase cytokine delivery to inflammatory macrophages. ELISA was used to quantify bioactive cytokine inside and releasing from NanoLIF. NanoLIF biological activity was measured using the M1 murine leukemia cell proliferation assay.

RESULTS

NanoLIF and CD11b-NanoLIF had diameters of approximately 30 nm, neutral surface charge, and physicochemical stability retaining biological activity of the cytokine during incubation at 25°C for 12 h. NanoLIF particles released LIF relatively fast from 0 to 6 h after incubation at 37°C followed by slow release from 24 to 72 h according to a two-phase exponential decay model. NanoLIF and CD11b-NanoLIF significantly decreased M1 cell proliferation over 72 h compared to free LIF.

CONCLUSIONS

NanoLIF and CD11b-NanoLIF preserved the metabolic stability and biological activity of LIF in vitro. These results are promising to improve the therapeutic potential of LIF in treating neurodegenerative and inflammatory diseases.

Magnetic and pH dual-responsive mesoporous silica nanocomposites for effective and low-toxic photodynamic therapy

Nonspecific targeting, large doses and phototoxicity severely hamper the clinical effect of photodynamic therapy (PDT). In this work, superparamagnetic Fe₃O₄ mesoporous silica nanoparticles grafted by pH-responsive block polymer polyethylene glycol-b-poly(aspartic acid) (PEG-b-PAsp) were fabricated to load the model photosensitizer rose bengal (RB) in the aim of enhancing the efficiency of PDT. Compared to free RB, the nanocomposites (polyethylene glycol-b-polyaspartate-modified rose bengal-loaded magnetic mesoporous silica [RB−MMSNs]) could greatly enhance the cellular uptake due to their effective endocytosis by mouse melanoma B16 cell and exhibited higher induced apoptosis although with little dark toxicity. RB−MMSNs had little dark toxicity and even much could be facilitated by magnetic field in vitro. RB−MMSNs demonstrated 10 times induced apoptosis efficiency than that of free RB at the same RB concentration, both by cell counting kit-8 (CCK-8) result and apoptosis detection. Furthermore, RB−MMSNs-mediated PDT in vivo on tumor-bearing mice showed steady physical targeting of RB−MMSNs to the tumor site; tumor volumes were significantly reduced in the magnetic field with green light irradiation. More importantly, the survival time of tumor-bearing mice treated with RB−MMSNs was much prolonged. Henceforth, polyethylene glycol-b-polyaspartate-modified magnetic mesoporous silica (MMSNs) probably have great potential in clinical cancer photodynamic treatment because of their effective and low-toxic performance as photosensitizers’ vesicles.

Optimization and evaluation of Oridonin-loaded Soluplus®-Pluronic P105 mixed micelles for oral administration

In this study, a new type of mixed micelles was developed using Soluplus^® (SOL) and Pluronic^® P105 (P105) for the encapsulation of Oridonin (ORN). Oridonin-loaded micelles (ORN-M) were simply prepared using solvent evaporation and characterized for particle size, particle morphology, encapsulation efficiency, and drug loading. In addition, the in vitro drug release behavior of ORN-M was assessed using the widely applied dialysis bag technique. The pharmacokinetic property of ORN was explored in rats after oral administration of ORN-M. Optimized ORN-M were of a small size (137.2±1.65nm) and spherical shape when the ratio of SOL:P105 was 3:1, with entrapment efficiency 90.48±1.85% and drug loading 15.08±0.38%. Oral absorption capacity of ORN was greatly enhanced with a relative bioavailability of 210.55% in comparison to that of in-house suspensions, which suggests that ORN-M shows significantly improved bioavailability and drug absorption characteristics. Overall, the optimized SOL-P105 dual mixed micelles show great potential for use as oral drug carriers for cancer treatment.

A Computational/Experimental Assessment of Antitumor Activity of Polymer Nanoassemblies for pH-Controlled Drug Delivery to Primary and Metastatic Tumors

PURPOSE

Polymer nanoassemblies (PNAs) with drug release fine-tuned to occur in acidic tumor regions (pH < 7) while sparing normal tissues (pH = 7.4) were previously shown to hold promise as nanoparticle drug carriers to effectively suppress tumor growth with reduced systemic toxicity. However, therapeutic benefits of pH-controlled drug delivery remain elusive due to complex interactions between the drug carriers, tumor cells with varying drug sensitivity, and the tumor microenvironment.

METHODS

We implement a combined computational and experimental approach to evaluate the in vivo antitumor activity of acid-sensitive PNAs controlling drug release in pH 5 ~ 7.4 at different rates [PNA1 (fastest) > PNA2 > PNA3 (slowest)].

RESULTS

Computational simulations projecting the transport, drug release, and antitumor activity of PNAs in primary and metastatic tumor models of colorectal cancer correspond well with experimental observations in vivo. The simulations also reveal that all PNAs could reach peak drug concentrations in tumors at 11 h post injection, while PNAs with slower drug release (PNA2 and PNA3) reduced tumor size more effectively than fast drug releasing PNA1 (24.5 and 20.3 vs 7.5%, respectively, as fraction of untreated control).

CONCLUSION

A combined computational/experimental approach may help to evaluate pH-controlled drug delivery targeting aggressive tumors that have substantial acidity.

Tailored functionalization of iron oxide nanoparticles for MRI, drug delivery, magnetic separation and immobilization of biosubstances

In this critical review, we outline various covalent and non-covalent approaches for the functionalization of iron oxide nanoparticles (IONPs). Tuning the surface chemistry and design of magnetic nanoparticles are described in relation to their applicability in advanced medical technologies and biotechnologies including magnetic resonance imaging (MRI) contrast agents, targeted drug delivery, magnetic separations and immobilizations of proteins, enzymes, antibodies, targeting agents and other biosubstances. We review synthetic strategies for the controlled preparation of IONPs modified with frequently used functional groups including amine, carboxyl and hydroxyl groups as well as the preparation of IONPs functionalized with other species, e.g., epoxy, thiol, alkane, azide, and alkyne groups. Three main coupling strategies for linking IONPs with active agents are presented: (i) chemical modification of amine groups on the surface of IONPs, (ii) chemical modification of bioactive substances (e.g. with fluorescent dyes), and (iii) the activation of carboxyl groups mainly for enzyme immobilization. Applications for drug delivery using click chemistry linking or biodegradable bonds are compared to non-covalent methods based on polymer modified condensed magnetic nanoclusters. Among many challenges, we highlight the specific surface engineering allowing both therapeutic and diagnostic applications (theranostics) of IONPs and magnetic/metallic hybrid nanostructures possessing a huge potential in biocatalysis, green chemistry, magnetic bioseparations and bioimaging.

Lanthanum strontium manganese oxide (LSMO) nanoparticles: a versatile platform for anticancer therapy

Multiple uses of LSMO nanoparticles in anticancer therapy.

Release, partitioning, and conjugation stability of doxorubicin in polymer micelles determined by mechanistic modeling

PURPOSE

To better understand the mechanistic parameters that govern drug release from polymer micelles with acid-labile linkers.

METHODS

A mathematical model was developed to describe drug release from block copolymer micelles composed of a poly(ethylene glycol) shell and a poly(aspartate) core, modified with drug binding linkers for pH-controlled release [hydrazide (HYD), aminobenzoate-hydrazide (ABZ), or glycine-hydrazide (GLY)]. Doxorubicin (Dox) was conjugated to the block copolymers through acid-labile hydrazone bonds. The polymer drug conjugates were used to prepare three polymer micelles (HYD-M, ABZ-M, and GLY-M). Drug release studies were performed to identify the factors governing pH-sensitive release of Dox. The effect of prolonged storage of copolymer material on release kinetics was also observed.

RESULTS

Biphasic drug release kinetics were observed for all three micelle formulations. The developed model was able to quantify observed release kinetics upon the inclusion of terms for unconjugated Dox and two populations of conjugated Dox. Micelle/water partitioning of Dox was also incorporated into the model and found significant in all micelles under neutral conditions but reduced under acidic conditions. The drug binding linker played a major role in drug release as the extent of Dox release at specific time intervals was greater at pH 5.0 than at pH 7.4 (HYD-M > ABZ-M > GLY-M). Mathematical modeling was also able to correlate changes in release kinetics with the instability of the hydrazone conjugation of Dox during prolonged storage.

CONCLUSION

These results illustrate the potential utility of mechanistic modeling to better assess release characteristics intrinsic to a particular drug/nanoparticle system.