Polyethylene glycol-polylactic acid nanoparticles modified with cysteine-arginine-glutamic acid-lysine-alanine fibrin-homing peptide for glioblastoma therapy by enhanced retention effect

A bacterial enzyme may correct 2-HG accumulation in human cancers

A significant proportion of lower-grade glioma as well as many other types of human cancers are associated with neomorphic mutations in IDH1/2 genes (mIDH1/2). These mutations lead to an aberrant accumulation of 2-hydroxyglutarate (2-HG). Interestingly, even cancers without mIDH1/2 can exhibit increased levels of 2-HG due to factors like hypoxia and extracellular acidity. Mounting evidence demonstrates that 2-HG competitively inhibits α-ketoglutarate dependent enzymes, such as JmjC-domain-containing histone demethylases (JHDMs), ten-eleven translocation enzymes (TETs), and various dioxygenases (e.g., RNA m6A demethylases and prolyl hydroxylases). Consequently, the hypermethylation of DNA, RNA, and histones, and the abnormal activities of hypoxia-inducible factors (HIFs) have profound impacts on the establishment of cancer metabolism and microenvironment, which promote tumor progression. This connection between the oncometabolite 2-HG and glioma holds crucial implications for treatments targeting this disease. Here, I hypothesize that an ectopic introduction of a bacterial 2-hydroxyglutarate synthase (2-HG synthase) enzyme into cancer cells with 2-HG accumulation could serve as a promising enzyme therapy for glioma and other types of cancers. While absent in human metabolism, 2-HG synthase in bacterial species catalyzes the conversion of 2-HG into propionyl-CoA and glyoxylate, two metabolites that potentially possess anti-tumor effects. For a broad spectrum of human cancers with 2-HG accumulation, 2-HG synthase-based enzyme therapy holds the potential to not only correct 2-HG induced cancer metabolism but also transform an oncometabolite into metabolic challenges within cancer cells.

Overcoming the blood-brain barrier for the therapy of malignant brain tumor: current status and prospects of drug delivery approaches

Besides the broad development of nanotechnological approaches for cancer diagnosis and therapy, currently, there is no significant progress in the treatment of different types of brain tumors. Therapeutic molecules crossing the blood-brain barrier (BBB) and reaching an appropriate targeting ability remain the key challenges. Many invasive and non-invasive methods, and various types of nanocarriers and their hybrids have been widely explored for brain tumor treatment. However, unfortunately, no crucial clinical translations were observed to date. In particular, chemotherapy and surgery remain the main methods for the therapy of brain tumors. Exploring the mechanisms of the BBB penetration in detail and investigating advanced drug delivery platforms are the key factors that could bring us closer to understanding the development of effective therapy against brain tumors. In this review, we discuss the most relevant aspects of the BBB penetration mechanisms, observing both invasive and non-invasive methods of drug delivery. We also review the recent progress in the development of functional drug delivery platforms, from viruses to cell-based vehicles, for brain tumor therapy. The destructive potential of chemotherapeutic drugs delivered to the brain tumor is also considered. This review then summarizes the existing challenges and future prospects in the use of drug delivery platforms for the treatment of brain tumors.

Local Delivery and Glioblastoma: Why Not Combining Sustained Release and Targeting?

Glioblastoma is one of the most aggressive brain tumors and is associated with a very low overall median survival despite the current treatment. The standard of care used in clinic is the Stupp's protocol which consists of a maximal resection of the tumor when possible, followed by radio and chemotherapy using temozolomide. However, in most cases, glioblastoma cells infiltrate healthy tissues and lead to fatal recurrences. There are a lot of hurdles to overcome in the development of new therapeutic strategies such as tumor heterogeneity, cell infiltration, alkylating agent resistance, physiological barriers, etc., and few treatments are on the market today. One of them is particularly appealing because it is a local therapy, which does not bring additional invasiveness since tumor resection is included in the gold standard treatment. They are implants: the Gliadel^® wafers, which are deposited post-surgery. Nevertheless, in addition to presenting important undesirable effects, it does not bring any major benefit in the therapy despite the strategy being particularly attractive. The purpose of this review is to provide an overview of recent advances in the development of innovative therapeutic strategies for glioblastoma using an implant-type approach. The combination of this local strategy with effective targeting of the tumor microenvironment as a whole, also developed in this review, may be of interest to alleviate some of the obstacles encountered in the treatment of glioblastoma.

Berberine-Loaded Thiolated Pluronic F127 Polymeric Micelles for Improving Skin Permeation and Retention

Background

Challenges associated with local antibacterial and anti-inflammatory drugs include low penetration and retention of drugs at the expected action site. Additionally, improving these challenges allows for the prevention of side effects that are caused by drug absorption into the systemic circulation and helps to safely treat local skin diseases.

Methods

In the current study, we successfully prepared a thiolated pluronic F127 polymer micelles (BTFM), which binds to keratin through a disulphide bond, to produce skin retention. In addition, the small particle size of polymer micelles promotes the penetration of carriers into the skin. The current study was divided into two experiments: an in vitro experiment; an in vivo experiment that involved the penetration of the micelle-loaded drugs into the skin of rats, the skin irritation test and the anti-inflammatory activity of the drug-loaded micelles on dimethyl benzene-induced ear edema in mice.

Results

Results from our in vitro transdermal experiment revealed that the amount of drug absorbed through the skin was decreased after the drug was loaded in the BTFM. Further, results from the vivo study, which used fluorescence microscopy to identify the location of the BTFM after penetration, revealed that there was strong fluorescence in the epidermis layer, but there was no strong fluorescence in the deep skin layer. In addition, the BTFM had a very good safety profile with no potentially hazardous skin irritation and transdermal administration of BTFM could significantly suppress ear edema induced by dimethyl benzene. Therefore, these findings indicated that BTFM reduced the amount of drug that entered the systemic circulation. Our results also demonstrated that the BTFM had a certain affinity for keratin.

Conclusion

Our experimental results suggest that the BTFM may be an effective drug carrier for local skin therapy with good safety profile.

High-throughput quantitative microscopy-based half-life measurements of intravenously injected agents

Accurate analysis of blood concentration and circulation half-life is an important consideration for any intravenously administered agent in preclinical development or for therapeutic application. However, the currently available tools to measure these parameters are laborious, expensive, and inefficient for handling multiple samples from complex multivariable experiments. Here we describe a robust high-throughput quantitative microscopy-based method to measure the blood concentration and circulation half-life of any fluorescently labeled agent using only a small (2 µL) amount of blood volume, enabling additional end-point measurements to be assessed in the same subject. To validate this method, we demonstrate its use to measure the circulation half-life in mice of two types of fluorescently labeled polymeric nanoparticles of different sizes and surface chemistries and of a much smaller fluorescently labeled monoclonal antibody. Furthermore, we demonstrate the improved accuracy of this method compared to previously described methods.

A dual brain-targeting curcumin-loaded polymersomes ameliorated cognitive dysfunction in intrahippocampal amyloid-β1-42-injected mice

Due to the impermeability of the blood–brain barrier and the nonselective distribution of drugs in the brain, the therapeutic access to intractable neurological disorders is challenging. In this study, dual brain-targeting polymersomes (POs) functionalized by transferrin and Tet-1 peptide (Tf/Tet-1-POs) promoted the transportation of curcumin into the brain and provided neuroprotection. The modification of the ligands that bind to the surface of POs was revealed by X-ray photoelectron spectroscopy analysis. The cell uptake of a coculture model of mouse brain capillary endothelial cells with neurons showed that the Tf/Tet-1-POs had significant transportation properties and possessed affinity for neurons. The pharmacokinetic analysis showed that the blood–brain barrier permeability–surface efficiency of the Tf/Tet-1-POs was 0.28 mL/h/g and that the brain tissue uptake rate (% ID/g) was 0.08, which were significant compared with the controls (P<0.05). The curcumin-encapsulated Tf/Tet-1-POs provided neuroprotection and ameliorated cognitive dysfunction in intrahippocampal amyloid-β_1–42-injected mice. These results suggest that the dual brain-targeting POs are more capable of drug delivery to the brain that can be exploited as a multiple noninvasive vehicle for targeting therapeutics.

Improved anti-glioblastoma efficacy by IL-13Rα2 mediated copolymer nanoparticles loaded with paclitaxel

Glioma presents one of the most malignant brain tumors, and the therapeutic effect is often limited due to the existence of brain tumor barrier. Based on interleukin-13 receptor α2 (IL-13Rα2) over-expression on glioma cell, it was demonstrated to be a potential receptor for glioma targeting. In this study, Pep-1-conjugated PEGylated nanoparticles loaded with paclitaxel (Pep-NP-PTX) were developed as a targeting drug delivery system for glioma treatment. The Pep-NP-PTX presented satisfactory size of 95.78 nm with narrow size distribution. Compared with NP-PTX, Pep-NP-PTX exhibited significantly enhanced cellular uptake in C6 cells (p < 0.001). The in vitro anti-proliferation evaluation showed that the IC50 were 146 ng/ml and 349 ng/ml of Pep-NP-PTX and NP-PTX, respectively. The in vivo fluorescent image results indicated that Pep-NP had higher specificity and efficiency in intracranial tumor accumulation. Following intravenous administration, Pep-NP-PTX could enhance the distribution of PTX in vivo glioma section, 1.98, 1.91 and 1.53-fold over that of NP-PTX group after 0.5, 1 and 4 h, respectively. Pep-NP-PTX could improve the anti-glioma efficacy with a median survival time of 32 days, which was significantly longer than that of PTX-NP (23 days) and Taxol(®) (22 days). In conclusion, Pep-NP-PTX is a potential targeting drug delivery system for glioma treatment.