Intelligent Nanoparticles for Advanced Drug Delivery in Cancer Treatment

Nanomedicine associated with photodynamic therapy for glioblastoma treatment

Glioblastoma, also known as glioblastoma multiforme (GBM), is the most recurrent and malignant astrocytic glioma found in adults. Biologically, GBMs are highly aggressive tumors that often show diffuse infiltration of the brain parenchyma, making complete surgical resection difficult. GBM is not curable with surgery alone because tumor cells typically invade the surrounding brain, rendering complete resection unsafe. Consequently, present-day therapy for malignant glioma remains a great challenge. The location of the invasive tumor cells presents several barriers to therapeutic delivery. The blood-brain barrier regulates the trafficking of molecules to and from the brain. While high-grade brain tumors contain some "leakiness" in their neovasculature, the mechanisms of GBM onset and progression remain largely unknown. Recent advances in the understanding of the signaling pathways that underlie GBM pathogenesis have led to the development of new therapeutic approaches targeting multiple oncogenic signaling aberrations associated with the GBM. Among these, drug delivery nanosystems have been produced to target therapeutic agents and improve their biodistribution and therapeutic index in the tumor. These systems mainly include polymer or lipid-based carriers such as liposomes, metal nanoparticles, polymeric nanospheres and nanocapsules, micelles, dendrimers, nanocrystals, and nanogold. Photodynamic therapy (PDT) is a promising treatment for a variety of oncological diseases. PDT is an efficient, simple, and versatile method that is based on a combination of a photosensitive drug and light (generally laser-diode or laser); these factors are separately relatively harmless but when used together in the presence of oxygen molecules, free radicals are produced that initiate a sequence of biological events, including phototoxicity, vascular damage, and immune responses. Photodynamic pathways activate a cascade of activities, including apoptotic and necrotic cell death in both the tumor and the neovasculature, leading to a permanent lesion and destruction of GBM cells that remain in the healthy tissue. Glioblastoma tumors differ at the molecular level. For example, gene amplification epidermal growth factor receptor and its receptor are more highly expressed in primary GBM than in secondary GBM. Despite these distinguishing features, both types of tumors (primary and secondary) arise as a result dysregulation of numerous intracellular signaling pathways and have standard features, such as increased cell proliferation, survival and resistance to apoptosis, and loss of adhesion and migration, and may show a high degree of invasiveness. PDT may promote significant tumor regression and extend the lifetime of patients who experience glioma progression.

Evolution and Clinical Translation of Drug Delivery Nanomaterials

With the advent of technology, the role of nanomaterials in medicine has grown exponentially in the last few decades. The main advantage of such materials has been exploited in drug delivery applications, due to their effective targeting that in turn reduces systemic toxicity compared to the conventional routes of drug administration. Even though these materials offer broad flexibility based on targeting tissue, disease, and drug payload, the demand for more effective yet highly biocompatible nanomaterial-based drugs is increasing. While therapeutically improved and safe materials have been introduced in nanomedicine platforms, issues related to their degradation rates and bio-distribution still exist, thus making their successful translation for human use very challenging. Researchers are constantly improving upon novel nanomaterials that are safer and more effective not only as therapeutic agents but as diagnostic tools as well, making the research in the field of nanomedicine ever more fascinating. In this review stress has been made on the evolution of nanomaterials that have been approved for clinical applications by the United States Food and Drug Administration Agency (FDA).

Effective encapsulation and biological activity of phosphorylated chemotherapeutics in calcium phosphosilicate nanoparticles for the treatment of pancreatic cancer

Drug resistant cancers like pancreatic ductal adenocarcinoma (PDAC) are difficult to treat, and nanoparticle drug delivery systems can overcome some of the limitations of conventional systemic chemotherapy. In this study, we demonstrate that FdUMP and dFdCMP, the bioactive, phosphorylated metabolites of the chemotherapy drugs 5-FU and gemcitabine, can be encapsulated into calcium phosphosilicate nanoparticles (CPSNPs). The non-phosphorylated drug analogs were not well encapsulated by CPSNPs, suggesting the phosphate modification is essential for effective encapsulation. In vitro proliferation assays, cell cycle analyses and/or thymidylate synthase inhibition assays verified that CPSNP-encapsulated phospho-drugs retained biological activity. Analysis of orthotopic tumors from mice treated systemically with tumor-targeted FdUMP-CPSNPs confirmed the in vivo up take of these particles by PDAC tumor cells and release of active drug cargos intracellularly. These findings demonstrate a novel methodology to efficiently encapsulate chemotherapeutic agents into the CPSNPs and to effectively deliver them to pancreatic tumor cells.

Nanoformulations for combination or cascade anticancer therapy

Nanoparticle drug formulations have been extensively investigated, developed, and in some cases, approved by the Food and Drug Administration (FDA). Synergistic combinations of drugs having distinct tumor-inhibiting mechanisms and non-overlapping toxicity can circumvent the issue of treatment resistance and may be essential for effective anti-cancer therapy. At the same time, co-delivery of a combined regimen by a single nanocarrier presents a challenge due to differences in solubility, molecular weight, functional groups and encapsulation conditions between the two drugs. This review discusses cellular and microenvironment mechanisms behind treatment resistance and nanotechnology-based solutions for effective anti-cancer therapy. Co-loading or cascade delivery of multiple drugs using of polymeric nanoparticles, polymer-drug conjugates and lipid nanoparticles will be discussed along with lipid-coated drug nanoparticles developed by our lab and perspectives on combination therapy.

Design of nanocarriers for nanoscale drug delivery to enhance cancer treatment using hybrid polymer and lipid building blocks

Polymer-lipid hybrid nanoparticles (PLN) are an emerging nanocarrier platform made from building blocks of polymers and lipids. PLN integrate the advantages of biomimetic lipid-based nanoparticles (i.e. solid lipid nanoparticles and liposomes) and biocompatible polymeric nanoparticles. PLN are constructed from diverse polymers and lipids and their numerous combinations, which imparts PLN with great versatility for delivering drugs of various properties to their nanoscale targets. PLN can be classified into two types based on their hybrid nanoscopic structure and assembly methods: Type-I monolithic matrix and Type-II core-shell systems. This article reviews the history of PLN development, types of PLN, lipid and polymer candidates, fabrication methods, and unique properties of PLN. The applications of PLN in delivery of therapeutic or imaging agents alone or in combination for cancer treatment are summarized and illustrated with examples. Important considerations for the rational design of PLN for advanced nanoscale drug delivery are discussed, including selection of excipients, synthesis processes governing formulation parameters, optimization of nanoparticle properties, improvement of particle surface functionality to overcome macroscopic, microscopic and cellular biological barriers. Future directions and potential clinical translation of PLN are also suggested.

The combined effect of thermal and chemotherapy on HeLa cells using magnetically actuated smart textured fibrous system

Thermal therapy combined with chemotherapy is one of the advanced and efficient methods to eradicate cancer. In this work, we fabricated magnetically actuated smart textured (MAST) fibrous systems and studied their candidacy for cancer treatment. The polycaprolactone-Fe₃ O₄ based MAST fibers were fabricated using electrospinning technique. These MAST fibrous systems contained carbogenic quantum dots as a tracking agent and doxorubicin hydrochloride anticancer drug. Additionally, as fabricated MAST fibrous systems were able to deliver anticancer drug and heat energy simultaneously to kill HeLa cells in a 10 min period in vitro. After treatment, the metabolic activity and morphology of HeLa cells were analyzed. In addition, the mechanism of cell death was studied using flow cytometry. Interestingly, the navigation of these systems in the fluid can be controlled with the application of gradient magnetic field. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 40-51, 2018.

Intelligent polymeric micelles: development and application as drug delivery for docetaxel

Recent years, docetaxel (DTX)-loaded intelligent polymeric micelles have been regarded as a promising vehicle for DTX for the reason that compared with conventional DTX-loaded micelles, DTX-loaded intelligent micelles not only preserve the basic functions of micelles such as DTX solubilization, enhanced accumulation in tumor tissue, and improved bioavailability and biocompatibility of DTX, but also possess other new properties, for instance, tumor-specific DTX delivery and series of responses to endogenous or exogenous stimulations. In this paper, basic theories and action mechanism of intelligent polymeric micelles are discussed in detail, especially the related theories of DTX-loaded stimuli-responsive micelles. The relevant examples of stimuli-responsive DTX-loaded micelles are also provided in this paper to sufficiently illustrate the advantages of relevant technology for the clinical application of anticancer drug, especially for the medical application of DTX.

Synthesis and characterization of pH-responsive nanoscale hydrogels for oral delivery of hydrophobic therapeutics

pH-responsive, polyanionic nanoscale hydrogels were developed for the oral delivery of hydrophobic therapeutics, such as common chemotherapeutic agents. Nanoscale hydrogels were designed to overcome physicochemical and biological barriers associated with oral delivery of hydrophobic therapeutics such as low solubility and poor permeability due to P-glycoprotein related drug efflux. Synthesis of these nanoscale materials was achieved by a robust photoemulsion polymerization method. By varying hydrophobic monomer components, four formulations were synthesized and screened for optimal physicochemical properties and in vitro biocompatibility. All of the responsive nanoscale hydrogels were capable of undergoing a pH-dependent transition in size. Depending on the selection of the hydrophobic monomer, the sizes of the nanoparticles vary widely from 120nm to about 500nm at pH 7.4. Polymer composition was verified using Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance spectroscopy. Polymer biocompatibility was assessed in vitro with an intestinal epithelial cell model. All formulations were found to have no appreciable cytotoxicity, defined as greater than 80% viability after polymer incubation. We demonstrate that these nanoscale hydrogels possess desirable physicochemical properties and exhibit agreeable in vitro biocompatibility for oral delivery applications.

Phytochemicals and Biogenic Metallic Nanoparticles as Anticancer Agents

Cancer is a leading cause of death worldwide. Several classes of drugs are available to treat different types of cancer. Currently, researchers are paying significant attention to the development of drugs at the nanoscale level to increase their target specificity and to reduce their concentrations. Nanotechnology is a promising and growing field with multiple subdisciplines, such as nanostructures, nanomaterials, and nanoparticles. These materials have gained prominence in science due to their size, shape, and potential efficacy. Nanomedicine is an important field involving the use of various types of nanoparticles to treat cancer and cancerous cells. Synthesis of nanoparticles targeting biological pathways has become tremendously prominent due to the higher efficacy and fewer side effects of nanodrugs compared to other commercial cancer drugs. In this review, different medicinal plants and their active compounds, as well as green-synthesized metallic nanoparticles from medicinal plants, are discussed in relation to their anticancer activities.

Elastin-like polypeptides in drug delivery

The use of recombinant elastin-like materials, or elastin-like recombinamers (ELRs), in drug-delivery applications is reviewed in this work. Although ELRs were initially used in similar ways to other, more conventional kinds of polymeric carriers, their unique properties soon gave rise to systems of unparalleled functionality and efficiency, with the stimuli responsiveness of ELRs and their ability to self-assemble readily allowing the creation of advanced systems. However, their recombinant nature is likely the most important factor that has driven the current breakthrough properties of ELR-based delivery systems. Recombinant technology allows an unprecedented degree of complexity in macromolecular design and synthesis. In addition, recombinant materials easily incorporate any functional domain present in natural proteins. Therefore, ELR-based delivery systems can exhibit complex interactions with both their drug load and the tissues and cells towards which this load is directed. Selected examples, ranging from highly functional nanocarriers to macrodepots, will be presented.