Mark Howell

Multifunctional chitosan magnetic-graphene (CMG) nanoparticles: a theranostic platform for tumor-targeted co-delivery of drugs, genes and MRI contrast agents

Combing chemotherapy with gene therapy has been one of the most promising strategies for the treatment of cancer. The noninvasive MRI with superparamagnetic iron oxide (SPIO) as contrast agent is one of the most effecitve techniques for evaluating the antitumor therapy. However, to construct a single system that can deliver efficiently gene, drug and SPIO to the cancer site remains a challenge. Herein, we report a chitosan functionalized magnetic graphene nanoparticle (CMG) platform for simultaneous gene/drug and SPIO delivery to tumor. The phantom and ex vivo MRI images suggest CMG as a strong T2 contrast-enhancing agent. The CMGs are biocompatible as evaluated by the WST assay and predominantly accumulate in tumors as shown by biodistribution studies and MRI. The anticancer drug doxorubicin (DOX) loaded CMGs (DOX-CMGs) release DOX faster at pH 5.1 than at pH 7.4, and more effective (IC50 = 2 μM) in killing A549 lung cancer cells than free DOX (IC50 = 4 μM). CMGs efficiently deliver DNA into A549 lung cancer cells and C42b prostate cancer cells. In addition, i.v. administration of GFP-plasmid encapsulated within DOX-CMGs into tumor-bearing mice has showed both GFP expression and DOX accumulation at the tumor site at 24 and 48 hrs after administration. These results indicate CMGs provide a robust and safe theranostic platform, which integrates targeted delivery of both gene medicine and chemotherapeutic drug(s), and enhanced MR imaging of tumors. The integrated chemo- and gene- therapeutic and diagnostic design of CMG nanoparticles shows promise for simultaneous targeted imaging, drug delivery and real -time monitoring of therapeutic effect for cancer.

A chitosan-modified graphene nanogel for noninvasive controlled drug release

UNLABELLED A near infrared (NIR) triggered drug delivery platform based on the chitosan-modified chemically reduced graphene oxide (CRGO) incorporated into a thermosensitive nanogel (CGN) was developed. CGN exhibited an NIR-induced thermal effect similar to that of CRGO, reversible thermo-responsive characteristics at 37-42 °C and high doxorubicin hydrochloride (DOX) loading capacity (48 wt%). The DOX loaded CGN (DOX-CGN) released DOX faster at 42 °C than at 37 °C. The fluorescence images revealed DOX expression in the cytoplasm of cancer cells when incubated with DOX-CGN at 37 °C but in the nucleus at 42 °C. Upon irradiation with NIR light (808 nm), a rapid, repetitive DOX release from the DOX-CGN was observed. Furthermore, the cancer cells incubated with DOX-CGN and irradiated with NIR light displayed significantly greater cytotoxicity than without irradiation owing to NIR-triggered increase in temperature leading to nuclear DOX release. These results demonstrate CGNs promising application for on-demand drug release by NIR light. FROM THE CLINICAL EDITOR These investigators report the successful development of a novel near infrared triggered drug delivery platform based on chitosan-modified chemically reduced graphene oxide (CRGO) incorporated into a thermosensitive nanogel (CGN).

A 3D Fibrous Scaffold Inducing Tumoroids: A Platform for Anticancer Drug Development

The development of a suitable three dimensional (3D) culture system for anticancer drug development remains an unmet need. Despite progress, a simple, rapid, scalable and inexpensive 3D-tumor model that recapitulates in vivo tumorigenesis is lacking. Herein, we report on the development and characterization of a 3D nanofibrous scaffold produced by electrospinning a mixture of poly(lactic-co-glycolic acid) (PLGA) and a block copolymer of polylactic acid (PLA) and mono-methoxypolyethylene glycol (mPEG) designated as 3P. Cancer cells cultured on the 3P scaffold formed tight irregular aggregates similar to in vivo tumors, referred to as tumoroids that depended on the topography and net charge of the scaffold. 3P scaffolds induced tumor cells to undergo the epithelial-to-mesenchymal transition (EMT) as demonstrated by up-regulation of vimentin and loss of E-cadherin expression. 3P tumoroids showed higher resistance to anticancer drugs than the same tumor cells grown as monolayers. Inhibition of ERK and PI3K signal pathways prevented EMT and reduced tumoroid formation, diameter and number. Fine needle aspirates, collected from tumor cells implanted in mice when cultured on 3P scaffolds formed tumoroids, but showed decreased sensitivity to anticancer drugs, compared to tumoroids formed by direct seeding. These results show that 3P scaffolds provide an excellent platform for producing tumoroids from tumor cell lines and from biopsies and that the platform can be used to culture patient biopsies, test for anticancer compounds and tailor a personalized cancer treatment.

Manganese-loaded lipid-micellar theranostics for simultaneous drug and gene delivery to lungs

Gadolinium (Gd) contrast agents are predominantly used for T(1) MR imaging. However, the high toxicity of Gd(3+) and potential side effects including nephrogenic systemic fibrosis have led to the search for alternative T(1) contrast agents. Since manganese (Mn) has paramagnetic properties with five unpaired electrons that permit high spin number, long electronic relaxation times, and labile water exchange, we evaluated Mn as a T(1) magnetic resonance imaging (MRI) contrast agent for lung imaging. Here we report on the design and synthesis of multifunctional lipid-micellar nanoparticles (LMNs) containing Mn oxide (M-LMNs) for MRI that can also be used for DNA and drug delivery. Oleic acid-coated MnO nanoparticles were encapsulated in micelles composed of polyethylene glycol (PEG-2000), phosphatidylethanolamine (PE), DC-cholesterol, and dioleoyl-phosphatidylethanolamine (DOPE). The particles are taken up in vitro by human embryonic kidney (HEK293), Lewis lung carcinoma (LLC1), and A549 cells and are devoid of cytotoxicity. When administered to mice intranasally, they preferentially accumulate in the lungs. In vitro phantom and ex vivo lung MRI results confirmed that M-LMNs are able to enhance T(1) MRI contrast. M-LMNs loaded with plasmid DNA and/or doxorubicin are efficiently taken up by HEK293 cells in vitro and by target cells in vivo. Taken together, these results demonstrate that M-LMNs are capable of simultaneously providing MRI contrast and DNA and/or drug delivery to target cells in the lung and therefore may prove useful as a lung theranostic, especially for lung cancers.

Dual-function theranostic nanoparticles for drug delivery and medical imaging contrast: perspectives and challenges for use in lung diseases

Theranostic nanoparticles with both therapeutic and imaging abilities have the promise to revolutionize diagnosis, therapy, and prognosis. Early and accurate detection along with swift treatment are the most important steps in the successful treatment of any disease. Over the last decade, a variety of nanotechnology-based platforms have been created in the hope of improving the treatment and diagnosis of a wide variety of diseases. However, significant hurdles still remain before theranostic nanoparticles can bring clinical solutions to the fight against chronic respiratory diseases. Some fundamental issues such as long-term toxicity, a precise understanding of the accumulation, degradation and clearance of these particles, and the correlation between basic physicochemical properties of these nanoparticles and their in vivo behavior have to be fully understood before they can be used clinically. To date, very little theranostic nanoparticle research has focused on the treatment and diagnosis of chronic respiratory illnesses. Nanomedicine approaches incorporating these theranostic nanoparticles could potentially be translated into clinical advances to improve diagnosis and treatment of these chronic respiratory diseases and enhance quality of life for the patients.

Phospholipid micelle encapsulated gadolinium oxide nanoparticles for imaging and gene delivery

We encapsulated gadolinium oxide (Gd2O3) nanoparticles within phospholipid micelles as a novel low cytotoxic T1-weighted MRI imaging contrast agent (MGdNPs) that can also deliver small molecules such as DNA plasmids. MGdNPs show relatively good MRI relaxivity values, negligible cytotoxicity, excellent cellular uptake and expression of DNA plasmids in vivo. Biodistribution studies in mice show that intranasal and intraperitoneal administration of MGdNPs can effectively target specific organs.

NOT THAT RIGID MIDGETS AND NOT SO FLEXIBLE GIANTS: ON THE ABUNDANCE AND ROLES OF INTRINSIC DISORDER IN SHORT AND LONG PROTEINS

Intrinsically disordered proteins or proteins with disordered regions are very common in nature. These proteins have numerous biological functions which are complementary to the biological activities of traditional ordered proteins. A noticeable difference in the amino acid sequences encoding long and short disordered regions was found and this difference was used in the development of length-dependent predictors of intrinsic disorder. In this study, we analyze the scaling of intrinsic disorder in eukaryotic proteins and investigate the presence of length-dependent functions attributed to proteins containing long disordered regions.

Surface Acoustic Waves (SAW)-Based Biosensing for Quantification of Cell Growth in 2D and 3D Cultures

Detection and quantification of cell viability and growth in two-dimensional (2D) and three-dimensional (3D) cell cultures commonly involve harvesting of cells and therefore requires a parallel set-up of several replicates for time-lapse or dose–response studies. Thus, developing a non-invasive and touch-free detection of cell growth in longitudinal studies of 3D tumor spheroid cultures or of stem cell regeneration remains a major unmet need. Since surface acoustic waves (SAWs) permit mass loading-based biosensing and have been touted due to their many advantages including low cost, small size and ease of assembly, we examined the potential of SAW-biosensing to detect and quantify cell growth. Herein, we demonstrate that a shear horizontal-surface acoustic waves (SH-SAW) device comprising two pairs of resonators consisting of interdigital transducers and reflecting fingers can be used to quantify mass loading by the cells in suspension as well as within a 3D cell culture platform. A 3D COMSOL model was built to simulate the mass loading response of increasing concentrations of cells in suspension in the polydimethylsiloxane (PDMS) well in order to predict the characteristics and optimize the design of the SH-SAW biosensor. The simulated relative frequency shift from the two oscillatory circuit systems (one of which functions as control) were found to be concordant to experimental data generated with RAW264.7 macrophage and A549 cancer cells. In addition, results showed that SAW measurements per se did not affect viability of cells. Further, SH-SAW biosensing was applied to A549 cells cultured on a 3D electrospun nanofiber scaffold that generate tumor spheroids (tumoroids) and the results showed the devices ability to detect changes in tumor spheroid growth over the course of eight days. Taken together, these results demonstrate the use of SH-SAW device for detection and quantification of cell growth changes over time in 2D suspension cultures and in 3D cell culture models, which may have potential applications in both longitudinal 3D cell cultures in cancer biology and in regenerative medicine.

Three- and Four-Dimensional Spheroid and FiSS Tumoroid Cultures: Platforms for Drug Discovery and Development and Translational Research

There have been remarkable improvements in our understanding of cancer biology. However, therapeutic improvements, with a few exceptions, have been minimal. Also, significant challenges remain in translating fundamental discoveries in cancer biology and genetics into effective drugs and cures. Traditional two-dimensional monolayer cell cultures lack predictive value, resulting in a >90% failure rate of compounds in clinical trials. A developing cancer is a symbiotic tissue consisting of cancer cells, including cancer stem cells (CSCs), and cohabitating with the components of its environment to form a tumor microenvironment (TME) niche. Throughout the process of tumorigenesis, ubiquitous autocrine and paracrine signaling between the cellular and noncellular components of the TME dictates the milieu and structure of this niche. Arising out of such interactions are the cancer cells phenotypic characteristics, such as stemness, epithelial mesenchymal transformation (EMT), and drug resistance which in turn greatly affect the response of these cells to drug therapy. For these reasons, in order to delineate the mechanism of tumorigenesis and in the process discover drugs that will have greatest impact on tumor growth, it becomes imperative to study the cancer cell in context of its microenvironment. In the present review, we enumerate the advantages of three- and four-dimensional (3D and 4D) cell cultures and describe the various cell culture platforms that are being used to study tumorigenesis in vitro. These culture systems will not only aid in the study of tumor progression complexities in a cost-effective and rapid manner; they also are expected to facilitate the discovery and delivery of therapeutic regimens that will have more success making it to the clinic.

Sertoli Cells Loaded with Doxorubicin in Lipid Micelles Reduced Tumor Burden and Dox-Induced Toxicity

The toxic side effects of doxorubicin (Dox) limit its long-term use as a lung cancer chemotherapeutic. Additionally, drug delivery to the deep lung is challenging. To address these challenges, isolated rat Sertoli cells (SCs) were preloaded with Dox conjugated to lipid micelle nanoparticles (SC-DLMNs) and delivered to mouse lungs. These immunocompetent cells, when injected intravenously, travel to the lung, deliver the payload, and get cleared by the system quickly without causing any adverse reaction. We observed that SC-DLMNs effectively treated Lewis lung carcinoma 1-induced lung tumors in mice and the drug efficacy was comparable to SC-Dox treatment. Mice treated with SC-DLMNs also showed significantly less toxicity compared to those treated with SC-Dox. The encapsulation of Dox in lipid micelle nanoparticles reduced the toxicity of Dox and the SC-based delivery method ensured drug delivery to the deep lung without evoking any immune response. Taken together, these results provide a novel SC-based nanoparticle drug delivery method for improved therapeutic outcome of cardiotoxic antilung cancer drugs.