Anamaria Orza

Electrically conductive gold-coated collagen nanofibers for placental-derived mesenchymal stem cells enhanced differentiation and proliferation.

Gold-coated collagen nanofibers (GCNFs) were produced by a single-step reduction process and used for the growth and differentiation of human adult stem cells. The nanomaterials were characterized by a number of analytical techniques including electron microscopy and spectroscopy. They were found to be biocompatible and to improve the myocardial and neuronal differentiation process of the mesenchymal stem cells isolated from the placental chorionic component. The expression of specific differentiation markers (atrium, natriuretic peptide, actin F and actin monomer, glial fibrilary acidic protein, and neurofilaments) was investigated by immunocytochemistry.

Reversing chemoresistance of malignant glioma stem cells using gold nanoparticles

The low rate of survival for patients diagnosed with glioblastoma may be attributed to the existence of a subpopulation of cancer stem cells. These stem cells have certain properties that enable them to resist chemotherapeutic agents and ionizing radiation. Herein, we show that temozolomide-loaded gold nanostructures are efficient in reducing chemoresistance and destroy 82.7% of cancer stem cells compared with a 42% destruction rate using temozolomide alone. Measurements of in vitro cytotoxicity and apoptosis indicate that combination with gold facilitated the ability of temozolomide, an alkylating drug, to alter the resistance of these cancer stem cells, suggesting a new chemotherapy strategy for patients diagnosed with inoperable recurrent malignant glioma.

Photoacoustic and photothermal cytometry using photoswitchable proteins and nanoparticles with ultrasharp resonances.

Photoswitchable fluorescent proteins (PSFPs) with controllable spectral shifts in emission in response to light have led to breakthroughs in cell biology. Conventional photoswitching, however, is not applicable to weakly fluorescent proteins. As an alternative, photothermal (PT) and photoacoustic (PA) spectroscopy have demonstrated a tremendous potential for studying absorbing nonfluorescent proteins and nanoparticles. However, little progress has been made in the development of switchable PT and PA probes with controllable spectral shifts in absorption. Here, we introduce the concept of photothermally switchable nanoparticles (PTSNs). To prove the concept, we demonstrated fast, reversible magnetic-PT switching of conventional and gold-coated magnetic nanoparticle clusters in cancer cells in vitro and PT switching of nonlinear ultrasharp plasmonic resonances in gold nanorods molecularly targeted to circulating cells in vivo. We showed that genetically encoded PSFPs with relatively slow switching can serve as triple-modal fluorescent, PT, and PA probes under static conditions, while PTSNs with ultrafast switching may provide higher PA sensitivity in the near-infrared window of tissue transparency under dynamic flow conditions. Application of nonlinear phenomena for super-resolution spectral PT and PA cytometry, microscopy, and spectral burning beyond the diffraction and spectral limits are also proposed.

Progress in materials for thermal ablation of cancer cells

Owing to the complexity of cancer biology, successful treatments must make use of multidisciplinary approaches that include genetic biology, materials science, chemistry, and physics. The development of nanotechnology as a mature science has provided new tools for the early detection and treatment of cancer by combining the synthesis of multifunctional nanosystems with the advanced capability of the targeted delivery of drugs and genes down to a single cell level. Nanomaterials with their unique optical, magnetic, and electrical properties have proven to be excellent candidates as thermal agents under the excitation of various electromagnetic fields (laser, alternating magnetic fields, or radiofrequency) that are capable of producing enough thermal energy for the specific destruction of the cancer cells both in vitro and in vivo. As a result, the use of such nanomaterials could open a new field in the area of cancer medicine given their ability to act as high resolution contrast agents and to thermally ablate tumors or individual cancer cells and to overcome some of the current limitations in cancer treatment.

Nanomaterials for targeted drug delivery to cancer stem cells

Abstract Recent developments in cancer biology have identified the existence of a sub-poplulation of cells – cancer stem cells (CSC) that are resistant to most traditional therapies (e.g. chemotherapy and radiotherapy) and have the ability to repair their damaged DNA. These findings have necessitated a break with traditional oncology management and encouraged new perspectives concerning cancer treatment. Understanding the functional biology of CSCs – especially the signaling pathways that are involved in their self-renewal mechanisms – is crucial for discovering new forms of treatment. In this review, we highlight current and future prospects for potential cancer therapies based on the use of nano-sized materials. Nanomaterials could revolutionize cancer management because of their distinctive features – unique surface chemistry, strong electronic, optic, and magnetic properties – that are found neither in bulk materials nor in single molecules. Based on these distinct properties, we believe that nanomaterials could be excellent candidates for use in CSC research in order to optimize cancer therapeutics. Moreover, we propose these nanomaterials for the inhibition of the self-renewal pathways of CSCs by focusing on the Hedgehog, Notch, and Wnt/β-catenin self-renewal mechanisms. By introducing these methods for the detection, targeting, and destruction of CSCs, an efficient alternative treatment for the incurable disease of cancer could be provided.

Multistructural biomimetic substrates for controlled cellular differentiation

Multidimensional scaffolds are considered to be ideal candidates for regenerative medicine and tissue engineering based on their potential to provide an excellent microenvironment and direct the fate of the cultured cells. More recently, the use of stem cells in medicine has opened a new technological opportunity for controlled tissue formation. However, the mechanism through which the substrate directs the differentiation of stem cells is still rather unclear. Data concerning its specific surface chemistry, topology, and its signaling ability need to be further understood and analyzed. In our study, atomic force microscopy was used to study the stiffness, roughness, and topology of the collagen (Coll) and metallized collagen (MC) substrates, proposed as an excellent substrate for regenerative medicine. The importance of signaling molecules was studied by constructing a new hybrid signaling substrate that contains both collagen and laminin extracellular matrix (ECM) proteins. The cellular response-such as attachment capability, proliferation and cardiac and neuronal phenotype expression on the metallized and non-metallized hybrid substrates (collagen + laminin)-was studied using MTT viability assay and immunohistochemistry studies. Our findings indicate that such hybrid materials could play an important role in the regeneration of complex tissues.

A nanocomposite of Au-AgI core/shell dimer as a dual-modality contrast agent for x-ray computed tomography and photoacoustic imaging

PURPOSE To develop a core/shell nanodimer of gold (core) and silver iodine (shell) as a dual-modal contrast-enhancing agent for biomarker targeted x-ray computed tomography (CT) and photoacoustic imaging (PAI) applications. METHODS The gold and silver iodine core/shell nanodimer (Au/AgICSD) was prepared by fusing together components of gold, silver, and iodine. The physicochemical properties of Au/AgICSD were then characterized using different optical and imaging techniques (e.g., HR- transmission electron microscope, scanning transmission electron microscope, x-ray photoelectron spectroscopy, energy-dispersive x-ray spectroscopy, Z-potential, and UV-vis). The CT and PAI contrast-enhancing effects were tested and then compared with a clinically used CT contrast agent and Au nanoparticles. To confer biocompatibility and the capability for efficient biomarker targeting, the surface of the Au/AgICSD nanodimer was modified with the amphiphilic diblock polymer and then functionalized with transferrin for targeting transferrin receptor that is overexpressed in various cancer cells. Cytotoxicity of the prepared Au/AgICSD nanodimer was also tested with both normal and cancer cell lines. RESULTS The characterizations of prepared Au/AgI core/shell nanostructure confirmed the formation of Au/AgICSD nanodimers. Au/AgICSD nanodimer is stable in physiological conditions for in vivo applications. Au/AgICSD nanodimer exhibited higher contrast enhancement in both CT and PAI for dual-modality imaging. Moreover, transferrin functionalized Au/AgICSD nanodimer showed specific binding to the tumor cells that have a high level of expression of the transferrin receptor. CONCLUSIONS The developed Au/AgICSD nanodimer can be used as a potential biomarker targeted dual-modal contrast agent for both or combined CT and PAI molecular imaging.

Single-Step Synthesis of Gold Nanowires Using Biomolecules as Capping Agent/Template: Applications for Tissue Engineering

Gold nanochains/nanowires were prepared by simultaneously reducing the gold salt in the presence of stabilizing biomolecules —L-aspartate and L-lysine, Collagen—that acts as capping agent and as a template in the formation of two-dimensional gold nanostructures. L-aspartate and L-lysine were used in order to form nanochains due to their ability to cap gold nanoparticles through an oriented attachment mechanism that leads to the formation of one-dimensional nanostructures. The formation of the nanowires was controlled by reducing the gold salt onto the surface of the collagen template. Transmission electron microscopy (TEM) and x-ray powder diffraction were employed in order to demonstrate the morphological and structural properties of the nanowires. In order to provide evidence of the possible applications of gold nanostructures as biocompatible substrates for tissue engineering, mesenchymal stem cells were cultured in their presence. MTT proliferation assays, as well as immunohistochemistry assays, were performed. The experiments demonstrated that each nanostructure stimulates cell proliferation, but better results were obtained in the case of collagen. Moreover, we noticed that the nanostructures are tracked inside of the cells, most likely in the perinuclear region of the stem cells.

One-Step Facile Synthesis of Highly Magnetic and Surface Functionalized Iron Oxide Nanorods for Biomarker-Targeted Applications

We report a one-step method for facile and sustainable synthesis of magnetic iron oxide nanorods (or IONRs) with mean lengths ranging from 25 to 50 nm and mean diameters ranging from 5 to 8 nm. The prepared IONRs are highly stable in aqueous media and can be surface functionalized for biomarker-targeted applications. This synthetic strategy involves the reaction of iron(III) acetylacetonate with polyethyleneimine in the presence of oleylamine and phenyl ether, followed by thermal decomposition. Importantly, the length and diameter as well as the aspect ratio of the prepared IONRs can be controlled by modulating the reaction parameters. We show that the resultant IONRs exhibit stronger magnetic properties compared to those of the widely used spherical iron oxide nanoparticles (IONPs) at the same iron content. The increased magnetic properties are dependent on the aspect ratio, with the magnetic saturation gradually increasing from 10 to 75 emu g-1 when increasing length of the IONRs, 5 nm in diameter, from 25 to 50 nm. The magnetic resonance imaging (MRI) contrast-enhancing effect, as measured in terms of the transverse relaxivity, r2, increased from 670.6 to 905.5 mM-1 s-1, when increasing the length from 25 to 50 nm. When applied to the immunomagnetic cell separation of the transferrin receptor (TfR)-overexpressed medulloblastoma cells using transferrin (Tf) as the targeting ligand, Tf-conjugated IONRs can capture 92 ± 3% of the targeted cells under a given condition (2.0 × 104 cells/mL, 0.2 mg Fe/mL concentration of magnetic materials, and 2.5 min of incubation time) compared to only 37 ± 2% when using the spherical IONPs, and 14 ± 2% when using commercially available magnetic beads, significantly improving the efficiency of separating the targeted cells.

Combined Computed Tomorgraphy and Pgotoacustic Imaging using Dual Modal Targeted Contract Agents

I order to improve the effectiveness of cancer treatment an accurate detection and localization of the tumor is necessary. By combining the Computed Tomography (CT) and Photoacoustic Imaging (PAT), a non-invasive anatomic diagnostic imaging and an intraoperative optical modality would be valuable to provide fine morphological details for accurate tumor detection and localization. Here, I report the development of new contrast agents as dual-modality molecules with extend properties (specific-targeting and therapy capability) able to combine the strengths of both CT and PAT imaging modality with resulted complementary diagnostic information.Background: Peritoneal dissemination is characterized by an aggressive clinical course, therapeutic resistance, and striking molecular heterogeneity. Cancer stem-likecells (CSCs) closely model this molecular heterogeneity and likely have a key role in tumor recurrence and therapeutic resistance. Emerging evidence indicates that signal transducer and activator of transcription3 (STAT3) is an important mediator of tumor cell survival, growth, and invasion in peritoneal dissemination that correlated with PIM-1 expression. Herein, we generated characterized 12 clones cells populations in gastric tumors with distinct properties that have stem cell-like characteristics, to evaluate the translational potential therapeutics by PIM-1 inhibitors.T discovery of CALR mutations in myeloproliferative neoplasms highlighted importance of Ca2+ homeostasis in megakaryocytic cells. Megakaryocytes express N-methyl-D-aspartate receptors (NMDARs) known to mediate glutamateinduced Ca2+ entry in other cells. However, the roles of glutamate and NMDARs in normal and malignant megakaryocytes are not known. The aim of this study was to determine whether NMDARs provide a novel pathway for Ca2+ entry into leukaemic megakaryoblasts and if so, whether modulating NMDAR activity could influence leukaemia cell growth. Expression of NMDAR subunits was examined in human bone marrow including neoplastic and megakaryoblastic leukaemia cell lines (Meg-01, Set-2 and K-562). Well-established NMDAR modulators (agonists and antagonists) were employed to determine NMDAR effects on the levels of intracellular Ca2+, cell viability, proliferation and differentiation. We found that human leukaemic cells expressed distinct combinations of the NMDAR subunits. Low concentrations of glutamate and NMDAR antagonists (riluzole, memantine, MK-801 and AP5; 5-100 μM) attenuated cell growth in culture mostly through the inhibition of cell proliferation. The use-dependent NMDAR antagonist, memantine (100 μM) reduced Meg-01 viability to 16±10% of controls (IC50 20 μM) and inhibited Meg-01 proliferation to 41±6% (IC50 36 μM). Further, after three days in the presence of NMDAR antagonists, cells acquired morphologic and immunophenotypic features of megakaryocytic differentiation. Our findings indicate that NMDARs provide a novel pathway for Ca2+ entry into leukaemic megakaryoblasts that supports cell proliferation. NMDAR inhibitors counteract these effects suggesting a novel way to interrupt growth of this type of leukaemia.O of the various therapies available for the treatment of colorectal cancer, chemotherapy was considered as the vastly used one owing to its faster availability of the drug mainly in the form of intravenous route by injections. But the main limitation associated with the chemotherapy is its harmful cytotoxic effects to the healthy cells, thereby minimizing the therapeutic effectiveness of various marketed drugs like oxaliplatin, 5-fluorouracil etc. Also cancer cells develop resistance to the above drugs after treatment for some time, which may be termed as multidrug resistance. So various alternatives of delivery systems such as nanoparticulate technology (like solid lipid nanoparticles, liposomes, enteric coated, pH-responsive, polymeric nanoparticles), Immuno conjugates (antibody conjugates, protein conjugates etc.) gained prominence for effective treatment of colorectal cancer by imparting site specificity of the active pharmaceutical ingredient there by reducing the toxicity of healthy cells and increasing the therapeutic efficacy of the drug. The nanoparticulate approach also helps in easy penetrability of the drug into the tumors owing to its decrease in particle size making it as an alternative for chemotherapy. As the particle size gets below 400 nm, it prevents elimination by reticulo endothelial system making it available mostly. Also the use of various lipids in the preparation of nanoparticles helps the drug to penetrate inside the tumor due to their hydrophobic outer layer as opposed to the chemotherapy where the drug is distributed evenly from systemic circulation to all rapidly dividing cells. Also so many drugs suffer from multi drug resistance (example; Cisplatin), which may be due to the efflux of the drug by p-gp glycoproteins present at the tumor cell surface. The alternatives to chemotherapy help the drug in bypassing the multi drug resistance by formulating them as immuno nanoparticles where they are conjugated with antibody thus helping in its intracellular penetration by receptor mediated endocytosis. These all limitations and novel approaches to overcome those limitations of chemotherapy demands for a detailed view on these alternatives.p regulates cell adhesion and migration by mediating tyrosine receptor kinase signaling. Tight regulation of p130Cas expression is critical for the maintenance of cell motility, survival and apoptosis in various cell types. Several studies reveal that transcriptional and post-translational control of p130Cas is important to maintain its expression and activity. To explore novel regulatory mechanisms for p130Cas expression, we investigated the effect of microRNAs on p130Cas level in human breast cancer cells. Here, we provide experimental evidences that miR-329 is a novel factor regulating p130Cas expression. miR-329 down-regulates cell migration and invasion thereby suppress tumor growth via down-regulating p130Cas. Ectopic expression of p130Cas restored the inhibitory effects of miR-329 in tumor progression. Interestingly, relative expression of miR-329 and p130Cas is inversely correlated between normal and breast cancers; miR-329 decreased, while p130Cas increased in breast cancers. Taken together, our results suggest that miR-329 is a novel factor regulating p130Cas expression and aberrant expression of p130Cas is responsible for tumor progression in breast cancers.