Pluronic Nanotechnology for Overcoming Drug Resistance

Intracellular Delivery of Anti-Kirsten Rat Sarcoma Antibodies Mediated by Polymeric Micelles Exerts Strong In Vitro and In Vivo Anti-Tumorigenic Activity in Kirsten Rat Sarcoma-Mutated Cancers

The Kirsten rat sarcoma viral oncogene (KRAS) is one of the most well-known proto-oncogenes, frequently mutated in pancreatic and colorectal cancers, among others. We hypothesized that the intracellular delivery of anti-KRAS antibodies (KRAS-Ab) with biodegradable polymeric micelles (PM) would block the overactivation of the KRAS-associated cascades and revert the effect of its mutation. To this end, PM-containing KRAS-Ab (PM-KRAS) were obtained using Pluronic F127. The feasibility of using PM for antibody encapsulation as well as the conformational change of the polymer and its intermolecular interactions with the antibodies was studied, for the first time, using in silico modeling. In vitro, encapsulation of KRAS-Ab allowed their intracellular delivery in different pancreatic and colorectal cancer cell lines. Interestingly, PM-KRAS promoted a high proliferation impairment in regular cultures of KRAS-mutated HCT116 and MIA PaCa-2 cells, whereas the effect was neglectable in non-mutated or KRAS-independent HCT-8 and PANC-1 cancer cells, respectively. Additionally, PM-KRAS induced a remarkable inhibition of the colony formation ability in low-attachment conditions in KRAS-mutated cells. In vivo, when compared with the vehicle, the intravenous administration of PM-KRAS significantly reduced tumor volume growth in HCT116 subcutaneous tumor-bearing mice. Analysis of the KRAS-mediated cascade in cell cultures and tumor samples showed that the effect of PM-KRAS was mediated by a significant reduction of the ERK phosphorylation and a decrease in expression in the stemness-related genes. Altogether, these results unprecedently demonstrate that the delivery of KRAS-Ab mediated by PM can safely and effectively reduce the tumorigenicity and the stemness properties of KRAS-dependent cells, thus bringing up new possibilities to reach undruggable intracellular targets.

pH-sensitive polymer-based carriers as a useful approach for oral delivery of therapeutic protein: A review

There are many proteins and enzymes in the human body, and their dysfunction can lead to disease. The use of proteins as a drug is common in various diseases such as diabetes. Proteins are hydrophilic molecules whose spatial structure is critical to their correct function. There are different ways to the administration of proteins. Protein structures are degraded by gastric acid and enzymes in the gastrointestinal tract and have a slight ability to permeation from the gastrointestinal epithelium due to their large hydrophilic nature. Therefore, their oral use has limitations. Since the oral use of drugs is one of the best and easiest routes for patients, many studies have been done to increase the stability, penetration and ultimately increase the bioavailability of proteins through oral administration. One of the studied strategies for oral delivery of protein is the use of pH-sensitive polymer-based carriers. These carriers use different pH-sensitive polymers such as eudragit®, chitosan, dextran, and alginate. The use of pH-sensitive polymer-based carriers by protecting the protein from stomach acid (low pH) and degrading enzymes, increasing permeability, and maintaining the spatial structure of the protein leads to increased bioavailability. In this review, we focus on the various polymers used to prepare pH-sensitive polymer-based carriers for the oral delivery of proteins.

Highlights in poloxamer-based drug delivery systems as strategy at local application for vaginal infections

Infectious diseases related to the vagina include diseases caused by the imbalance of the vaginal flora and by sexually transmitted infections. Some of these present themselves as a public health problem due to the lack of efficient treatment that leads to their complete cure, and others due to the growing resistance to drugs used in therapy. In this sense, new treatment strategies are desirable, with vaginal administration rout being a great choice since can bypass first-pass metabolism and decrease drug interactions and adverse effects. However, it is worth highlighting limitations related to patient's discomfort at application time. Thereby, the use of poloxamer-based drug delivery systems is desirable due its stimuli-sensitive characteristic. Therefore, the present review reports a brief overview of poloxamer properties, biological behavior and advances in poloxamer applications in controlled drug release systems for infectious diseases related to the vagina treatment and prevention.

New Formulation of a Methylseleno-Aspirin Analog with Anticancer Activity towards Colon Cancer

Aspirin (ASA) has attracted wide interest of numerous scientists worldwide thanks to its chemopreventive and chemotherapeutic effects, particularly in colorectal cancer (CRC). Incorporation of selenium (Se) atom into ASA has greatly increased their anti-tumoral efficacy in CRC compared with the organic counterparts without the Se functionality, such as the promising antitumoral methylseleno-ASA analog (1a). Nevertheless, the efficacy of compound 1a in cancer cells is compromised due to its poor solubility and volatile nature. Thus, 1a has been formulated with native α-, β- and γ-cyclodextrin (CD), a modified β-CD (hydroxypropyl β-CD, HP-β-CD) and Pluronic F127, all of them non-toxic, biodegradable and FDA approved. Water solubility of 1a is enhanced with β- and HP- β-CDs and Pluronic F127. Compound 1a forms inclusion complexes with the CDs and was incorporated in the hydrophobic core of the F127 micelles. Herein, we evaluated the cytotoxic potential of 1a, alone or formulated with β- and HP- β-CDs or Pluronic F127, against CRC cells. Remarkably, 1a formulations demonstrated more sustained antitumoral activity toward CRC cells. Hence, β-CD, HP-β-CD and Pluronic F127 might be excellent vehicles to improve pharmacological properties of organoselenium compounds with solubility issues and volatile nature.

Pluronic P123 modified nano micelles loaded with doxorubicin enhanced tumor-suppressing effect on drug-resistant breast cancer cells

OBJECTIVE

Nano micelles (NMs) have been widely used for various biomedical applications due to its unique physiochemical properties. This study aimed to investigated the anti-tumor effect of doxorubicin (Dox)-loaded Pluronic P123 (P123) and PEG2000-DSPE mixed NMs in drug-resistant breast cancer cells.

RESULTS

The expression of P-gp and MDR1 gene was highly expressed in MCF-7R but not MCF-7 cells. The cellular uptake of P123-PEG2000-DSPE (Dox) was higher than that of free Dox and PEG2000-DSPE (Dox) in MCF-7R cells. Furthermore, compared with free Dox, both PEG2000-DSPE (Dox) and P123-PEG2000-DSPE (Dox) significantly diminished cell viability, and promoted cell apoptosis in MCF-7R cells. In addition, the P123-modified NMs obviously inhibited the expression of P-gp and MDR1.

CONCLUSIONS

P123-PEG2000-DSPE (Dox) had a superior anti-tumor activity than PEG2000-DSPE (Dox) in MCF-7R cells through P-gp-mediated drug excretion and drug resistance mechanisms.

METHODS

The PEG2000-DSPE NMs (PEG2000-DSPE), P123 and PEG2000-DSPE mixed NMs (P123-PEG2000-DSPE), Dox-loaded PEG2000-DSPE NMs (PEG2000-DSPE (Dox)), and Dox-loaded Pluronic P123 and PEG2000-DSPE mixed NMs (P123-PEG2000-DSPE (Dox)) were prepared, and then the morphologies and the size distribution of PEG2000-DSPE (Dox) and P123-PEG2000-DSPE (Dox) were observed by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively.

Polymeric Micellar Formulation Enhances Antimicrobial and Anticancer Properties of Salinomycin

PURPOSE

Salinomycin (SAL) is a polyether compound that exhibits strong antimicrobial as well as anticancer activity. Nanomedicine has been at the forefront of drug delivery research with the aim of increasing the efficacy, specificity and reduce toxicity of drugs. There is an intersection between infection and cancer, and cancer patients are prone to bacterial infections. In this study, polymeric micelles were prepared using Pluronic® F127 (PM) to encapsulate SAL (PM_SAL) with the view of enhancing antimicrobial and anticancer activity.

METHODS

A Quality by Design (QbD) approach was utilized to synthesize PM_SAL, and nanoformulation activity was determined against bacterial (S. aureus, MRSA and E. coli). Effects on cancer cell line A549, i.e. cell viability, prevention of P-gp efflux, vimentin expression, effects on migratory ability of A549 cells. Anticancer activity was determined by ability to eradicate cancer stem-like cells.

RESULTS

PM_SAL demonstrated only efficacy against MRSA, being even higher than that obtained with SAL. In A549 cells, a 15-fold increase in P-gp's expression as well as a significant decrease of the cell's migration, was observed.

CONCLUSIONS

PM_SAL can interfere with the oncogenic protein VIM, involved in the crucial mechanisms EMT, downregulating its expression. Altogether data obtained indicates that this antibiotic and the developed polymeric micelle system is a very promising inhibitor of tumor cell growth.

Using superparamagnetic iron oxide nanoparticles to enhance bioavailability of quercetin in the intact rat brain

Background

Quercetin (QT) as a bioactive flavonoid has a potential therapeutic activity for numerous neuronal injuries and neurodegenerative diseases. However, the low absorption rate of QT, especially through the blood-brain barrier, restricts its bioactivity in the body. The current research took the advantage of superparamagnetic iron oxide nanoparticles (SPIONs) to enhance the bioavailability of quercetin.

Methods

Quercetin conjugated with SPIONs was prepared by means of nanoprecipitation method and was characterized by X-ray diffractometer, scanning electron microscope, and Fourier transformed infrared spectrometer analyses. Wistar male rats were orally fed by gavage with QT and QT-SPION at 50 and 100 mg/kg daily doses for 7 days. Using high-performance liquid chromatography (HPLC) method, biodistribution of QT was evaluated in plasma and brain tissue.

Results

The outcomes of this research revealed a higher concentration in the plasma and brain of the rats fed with QT-SPION in comparison to free QT.

Conclusion

The results of this study confirm that SPION as a targeted drug delivery system enhances the bioavailability of quercetin in the brain about ten folds higher than free quercetin and could be used for the treatment of neurodegenerative disorders.