Blood-brain barrier-penetrating amphiphilic polymer nanoparticles deliver docetaxel for the treatment of brain metastases of triple negative breast cancer

Multitargeted Nanoparticles Deliver Synergistic Drugs across the Blood-Brain Barrier to Brain Metastases of Triple Negative Breast Cancer Cells and Tumor-Associated Macrophages

Patients with brain metastases of triple negative breast cancer (TNBC) have a poor prognosis owing to the lack of targeted therapies, the aggressive nature of TNBC, and the presence of the blood-brain barrier (BBB) that blocks penetration of most drugs. Additionally, infiltration of tumor-associated macrophages (TAMs) promotes tumor progression. Here, a terpolymer-lipid hybrid nanoparticle (TPLN) system is designed with multiple targeting moieties to first undergo synchronized BBB crossing and then actively target TNBC cells and TAMs in microlesions of brain metastases. In vitro and in vivo studies demonstrate that covalently bound polysorbate 80 in the terpolymer enables the low-density lipoprotein receptor-mediated BBB crossing and TAM-targetability of the TPLN. Conjugation of cyclic internalizing peptide (iRGD) enhances cellular uptake, cytotoxicity, and drug delivery to brain metastases of integrin-overexpressing TNBC cells. iRGD-TPLN with coloaded doxorubicin (DOX) and mitomycin C (MMC) (iRGD-DMTPLN) exhibits higher efficacy in reducing metastatic burden and TAMs than nontargeted DMTPLN or a free DOX/MMC combination. iRGD-DMTPLN treatment reduces metastatic burden by 6-fold and 19-fold and increases host median survival by 1.3-fold and 1.6-fold compared to DMTPLN or free DOX/MMC treatments, respectively. These findings suggest that iRGD-DMTPLN is a promising multitargeted drug delivery system for the treatment of integrin-overexpressing brain metastases of TNBC.

Neuronanomedicine: An Up-to-Date Overview

The field of neuronanomedicine has recently emerged as the bridge between neurological sciences and nanotechnology. The possibilities of this novel perspective are promising for the diagnosis and treatment strategies of severe central nervous system disorders. Therefore, the development of nano-vehicles capable of permeating the blood⁻brain barrier (BBB) and reaching the brain parenchyma may lead to breakthrough therapies that could improve life expectancy and quality of the patients diagnosed with brain disorders. The aim of this review is to summarize the recently developed organic, inorganic, and biological nanocarriers that could be used for the delivery of imaging and therapeutic agents to the brain, as well as the latest studies on the use of nanomaterials in brain cancer, neurodegenerative diseases, and stroke. Additionally, the main challenges and limitations associated with the use of these nanocarriers are briefly presented.

Blood-Brain Delivery Methods Using Nanotechnology

Pathologies of the brain, of which brain cancer, Alzheimer's disease, Parkinson's disease, stroke, and multiple sclerosis, are some of the most prevalent, and that presently are poorly treated due to the difficulties associated with drug development, administration, and targeting to the brain. The existence of the blood-brain barrier, a selective permeability system which acts as a local gateway against circulating foreign substances, represents the key challenge for the delivery of therapeutic agents to the brain. However, the development of nanotechnology-based approaches for brain delivery, such as nanoparticles, liposomes, dendrimers, micelles, and carbon nanotubes, might be the solution for improved brain therapies.

Multifunctional smart hydrogels: potential in tissue engineering and cancer therapy

In recent years, clinical applications have been proposed for various hydrogel products. Hydrogels can be derived from animal tissues, plant extracts and/or adipose tissue extracellular matrices; each type of hydrogel presents significantly different functional properties and may be used for many different applications, including medical therapies, environmental pollution treatments, and industrial materials. Due to complicated preparation techniques and the complexities associated with the selection of suitable materials, the applications of many host-guest supramolecular polymeric hydrogels are limited. Thus, improvements in the design and construction of smart materials are highly desirable in order to increase the lifetimes of functional materials. Here, we summarize different functional hydrogels and their varied preparation methods and source materials. The multifunctional properties of hydrogels, particularly their unique ability to adapt to certain environmental stimuli, are chiefly based on the incorporation of smart materials. Smart materials may be temperature sensitive, pH sensitive, pH/temperature dual sensitive, photoresponsive or salt responsive and may be used for hydrogel wound repair, hydrogel bone repair, hydrogel drug delivery, cancer therapy, and so on. This review focuses on the recent development of smart hydrogels for tissue engineering applications and describes some of the latest advances in using smart materials to create hydrogels for cancer therapy.

Factors relating to the biodistribution & clearance of nanoparticles & their effects on in vivo application

Nanoparticles have promising biomedical applications for drug delivery, tumor imaging and tumor treatment. Pharmacokinetics are important for the in vivo application of nanoparticles. Biodistribution and clearance are largely defined as the key points of pharmacokinetics to maximize therapeutic efficacy and to minimize side effects. Different engineered nanoparticles have different biodistribution and clearance processes. The interactions of organs with nanoparticles, which are determined by the characteristics of the organs and the biochemical/physical properties of the nanoparticles, are a major factor influencing biodistribution and clearance. In this review, the clearance functions of organs and the properties related to pharmacokinetics, including nanoparticle size, shape, biodegradation and surface modifications are discussed.

Importance of integrating nanotechnology with pharmacology and physiology for innovative drug delivery and therapy - an illustration with firsthand examples

Nanotechnology has been applied extensively in drug delivery to improve the therapeutic outcomes of various diseases. Tremendous efforts have been focused on the development of novel nanoparticles and delineation of the physicochemical properties of nanoparticles in relation to their biological fate and functions. However, in the design and evaluation of these nanotechnology-based drug delivery systems, the pharmacology of delivered drugs and the (patho-)physiology of the host have received less attention. In this review, we discuss important pharmacological mechanisms, physiological characteristics, and pathological factors that have been integrated into the design of nanotechnology-enabled drug delivery systems and therapies. Firsthand examples are presented to illustrate the principles and advantages of such integrative design strategies for cancer treatment by exploiting 1) intracellular synergistic interactions of drug-drug and drug-nanomaterial combinations to overcome multidrug-resistant cancer, 2) the blood flow direction of the circulatory system to maximize drug delivery to the tumor neovasculature and cells overexpressing integrin receptors for lung metastases, 3) endogenous lipoproteins to decorate nanocarriers and transport them across the blood-brain barrier for brain metastases, and 4) distinct pathological factors in the tumor microenvironment to develop pH- and oxidative stress-responsive hybrid manganese dioxide nanoparticles for enhanced radiotherapy. Regarding the application in diabetes management, a nanotechnology-enabled closed-loop insulin delivery system was devised to provide dynamic insulin release at a physiologically relevant time scale and glucose levels. These examples, together with other research results, suggest that utilization of the interplay of pharmacology, (patho-)physiology and nanotechnology is a facile approach to develop innovative drug delivery systems and therapies with high efficiency and translational potential.

Apatinib + CPT-11 + S-1 for treatment of refractory brain metastases in patient with triple-negative breast cancer: Case report and literature review

RATIONALE

Brain metastasis (BM) is a rising challenge in forward-looking oncology, as its treatment choices are very limited, especially, after the failure of local treatment schemes.

PATIENT CONCERNS

We report on a 39-year-old Chinese woman who was diagnosed with stage IV triple-negative breast cancer(TNBC) with multiple brain, lung, and bone metastases. She had previously, undergone whole-brain radiation therapy. Paclitaxel, platinum, UTD1, capecitabine, gemcitabine, vinorelbine, and single-agent apatinib were then administered as first- to fifth-line therapies. She exhibited progression each time after a short period of disease stabilization.

DIAGNOSES

Triple-negative breast cancer.

INTERVENTIONS

The patient chose treatment with apatinib+CPT-11+S-1 as the sixth-line therapy.

OUTCOMES

A remarkable response of the brain, and lung metastases, and alleviation of the brain edema were achieved, and these effects persisted for 7 months.

LESSONS

We describe the significant anti-tumor effect of apatinib + CPT-11 + S-1 against BMs from breast cancer. This report is the first to suggest potential approaches to BM treatment using this scheme and describes the effects of an apatinib-containing regimen on BMs.

Clinically advancing and promising polymer-based therapeutics

In this review article, we will examine the history of polymers and their evolution from provisional World War II materials to medical therapeutics. To provide a comprehensive look at the current state of polymer-based therapeutics, we will classify technologies according to targeted areas of interest, including central nervous system-based and intraocular-, gastrointestinal-, cardiovascular-, dermal-, reproductive-, skeletal-, and neoplastic-based systems. Within each of these areas, we will consider several examples of novel, clinically available polymer-based therapeutics; in addition, this review will also include a discussion of developing therapies, ranging from the in vivo to clinical trial stage, for each targeted area of treatment. Finally, we will emphasize areas of patient care in need of more effective, accessible, and targeted treatment approaches where polymer-based therapeutics may offer potential solutions.

Role of the blood-brain barrier in metastatic disease of the central nervous system

Systemic therapy is an important backbone in the multimodal treatment approach of brain metastases. However, the blood-brain barrier or, more correctly, the blood-tumor barrier, as the properties of tumor-associated vessels differ from the physiologic state, potentially limits the passage of systemic drugs. Indeed, several preclinical and clinical investigations showed that the distribution of drugs is very heterogeneous within a given brain metastasis, despite the contrast enhancement in magnetic resonance imaging. Brain metastases may show lower intratumoral concentrations of some drugs as compared to extracranial tumor sites, resulting in mixed responses. Therefore, a more profound understanding of the role of the blood-brain/blood-tumor barrier is needed to effectively formulate clinical trial approaches on systemic therapy options in patients with brain metastases.

Vincristine liposomes with smaller particle size have stronger diffusion ability in tumor and improve tumor accumulation of vincristine significantly

The passive targeting is the premise of active targeting that could make nanocarrier detained in tumor tissue. The particle size is the most important factor that influences the diffusion and distribution of nanoparticle both in vivo and in vitro. In order to investigate the relationship between particle size and diffusion ability, two kinds of liposome loaded with Vincristine (VCR-Lip) were prepared. The diffusion behavior of VCR-Lip with different particle size and free VCR was compared through diffusion stability study. The diffusion ability from 12-well culture plate to Millipore transwell of each formulation reflected on HepG-2 cytotoxicity results. Different cell placement methods and drug adding positions were used to study the VCR-Lip diffusion behaviors, which influenced the apoptosis of HepG-2 cell. The different cell uptake of Nile red–Lip and free Nile red was compared when changed the adding way of fluorescent fluorescein. To study the penetration ability in HepG-2 tumor spheroids, we constructed 30 nm and 100 nm Cy5.5-Lip to compare with free Cy5.5. Then the anti-tumor effect, tissue distribution of free VCR injection, 30 nm and 100 nm VCR-Lip were further investigated on the HepG-2 tumor bearing nude mice. The results of these study showed that the diffusion ability of free drug and fluorescent fluorescein was remarkable stronger than which encapsulated in liposomes. Moreover, diffusion ability of smaller liposome was stronger than larger one. In this way, 30 nm liposome had not only faster and stronger tumor distribution than 100 nm liposome, but also higher tumor drug accumulation than free drug as well. Our study provided a new thinking to improve the targeting efficiency of nano drug delivery system, no matter passive or active targeting.

Biodegradable Micelles Based on Poly(ethylene glycol)-b-polylipopeptide Copolymer: A Robust and Versatile Nanoplatform for Anticancer Drug Delivery

Poly(ethylene glycol)-b-polypeptide block copolymer micelles, with excellent safety, are one of the most clinically studied nanocarriers for anticancer drug delivery. Notably, self-assembled nanosystems based on hydrophobic polypeptides showing typically a low drug loading and burst drug release are limited to preclinical studies. Here, we report that poly(ethylene glycol)-b-poly(α-aminopalmitic acid) (PEG-b-PAPA) block copolymer could be easily prepared with tailored M_n through ring-opening polymerization of α-aminopalmitic acid N-carboxyanhydride (APA-NCA). Interestingly, PEG-b-PAPA copolymers exhibited superb solubility in common organic solvents (including CHCl₃, CH₂Cl₂, and THF), while stable nanomicelles were formed in phosphate buffer, with a small size of 59 nm and a low critical micelle concentration of 2.38 mg/L. These polylipopeptide micelles (Lipep-Ms) allowed facile loading of a potent anticancer drug, docetaxel (DTX), likely due to the existence of a strong interaction between the lipophilic drug and polylipopeptide in the core. Notably, cRGD-peptide-functionalized Lipep-Ms (cRGD-Lipep-Ms) were also obtained with similar biophysical characteristics. The in vitro studies showed efficient cellular uptake of DTX-loaded cRGD-Lipep-Ms by B16F10 cells and fast intracellular drug release due to the enzymatic degradation of PAPA blocks in endo/lysosome, leading to a pronounced anticancer effect (IC₅₀ = 0.15 μg DTX equiv/mL). The in vivo therapy studies showed that DTX-cRGD-Lipep-Ms exhibited superior tumor growth inhibition of B16F10 melanoma, improved survival rate, and little side effects as compared to free DTX. These polylipopeptide micelles appear as a promising and robust nanoplatform for anticancer drug delivery.

Nanoparticles as Theranostic Vehicles in Experimental and Clinical Applications-Focus on Prostate and Breast Cancer

Prostate and breast cancer are the second most and most commonly diagnosed cancer in men and women worldwide, respectively. The American Cancer Society estimates that during 2016 in the USA around 430,000 individuals were diagnosed with one of these two types of cancers, and approximately 15% of them will die from the disease. In Europe, the rate of incidences and deaths are similar to those in the USA. Several different more or less successful diagnostic and therapeutic approaches have been developed and evaluated in order to tackle this issue and thereby decrease the death rates. By using nanoparticles as vehicles carrying both diagnostic and therapeutic molecular entities, individualized targeted theranostic nanomedicine has emerged as a promising option to increase the sensitivity and the specificity during diagnosis, as well as the likelihood of survival or prolonged survival after therapy. This article presents and discusses important and promising different kinds of nanoparticles, as well as imaging and therapy options, suitable for theranostic applications. The presentation of different nanoparticles and theranostic applications is quite general, but there is a special focus on prostate cancer. Some references and aspects regarding breast cancer are however also presented and discussed. Finally, the prostate cancer case is presented in more detail regarding diagnosis, staging, recurrence, metastases, and treatment options available today, followed by possible ways to move forward applying theranostics for both prostate and breast cancer based on promising experiments performed until today.