Methotrexate (MTX), a stoichiometric inhibitor of dihydrofolate reductase, is a chemotherapeutic agent for treating a variety of neoplasms. Impairment of drug import into cells and increase in drug export from cells may render cells resistant to MTX. MTX, when locally administered in a soluble form, is rapidly absorbed through capillaries into the circulatory system, which may also account for therapeutic failure in patients. To retain MTX within tumor cells for longer duration and alter its pharmacokinetic behavior, we proposed a new formulation of MTX bound to the gold nanoparticle (AuNP) that serves as drug carriers. In this study, we developed the MTX-AuNP conjugate and examined its cytotoxic effect in vitro and antitumor effect in vivo. Spectroscopic examinations revealed that MTX can be directly bound onto AuNP via the carboxyl group (-COOH) to form the MTX-AuNP complex and kinetically released from the nanoparticles. The accumulation of MTX is faster and higher in tumor cells treated with MTX-AuNP than that treated with free MTX. Notably, MTX-AuNP shows higher cytotoxic effects on several tumor cell lines compared with an equal dose of free MTX. This can be attributed to the "concentrated effect" of MTX-AuNP. Administration of MTX-AuNP suppresses tumor growth in a mouse ascites model of Lewis lung carcinoma (LL2), whereas an equal dose of free MTX had no antitumor effect. In conclusion, these results suggest that by combining nanomaterials with anticancer drugs MTX-AuNP may be more effective than free MTX for cancer treatment.

High atomic number material, such as gold, may be used in conjunction with radiation to provide dose enhancement in tumors. In the current study, we investigated the dose-enhancing effect and apoptotic potential of gold nanoparticles in combination with singledose clinical electron beams on B16F10 melanoma tumor-bearing mice. We revealed that the accumulation of gold nanoparticles was detected inside B16F10 culture cells after 18 h of incubation, and moreover, the gold nanoparticles were shown to be colocalized with endoplasmic reticulum and Golgi apparatus in cells. R adiation dose enhancement by high atomic number (Z) materials has long been investigated. In theory, loading high Z materials into the tumor could result in greater photoelectric absorption within the tumor than in surrounding tissues, and thereby enhance the dose delivered to a tumor during radiation therapy. At least 20 years ago, it was noted in vitro that this effect might be employed to enhance radiotherapy for cancer.(1) Accumulating studies have demonstrated the dose enhancement caused by high Z materials in kilovoltage beams (2)(3)(4) and in megavoltage beams.(5-8) Moreover, enhanced cell killing was also observed when cells were irradiated adjacent to high Z materials by kilovoltage X-rays. (9)(10)(11)(12) In clinical practice, electron beams from linear accelerators have increasingly taken the place of kilovoltage X-ray beams for skin and subcutaneous tumors because they offer distinct advantages in terms of dose uniformity in the target volume and in minimizing the dosage to deeper tissues.(13) Although kilovoltage beams could maximize tumor dose enhancement, it has technical restrictions. The use of kilovoltage X-rays produces significant dose heterogeneity inside the target tumor. (4,14) To be clinically useful, a radiosensitizer and/or dose enhancer should significantly increase the therapeutic ratio and should be readily available, easily utilized, and non-toxic. Gold (Au; Z = 79) or nanogold (gold nanoparticles, AuNP) showed doseenhancing effects in cell experiments, (15) the murine model,and through Monte Carlo calculations. (17) Gold nanoparticles have been actively investigated in a wide variety of biomedical applications due to their biocompatibility and ease of conjugation to biomolecules.(18-21) Besides, nanoparticles have the advantages of small size (1-100 nm) and ability to evade the immune system, (22,23) and also have been shown to preferentially accumulate in tumors. (24)(25)(26)(27)(28) While previous studies have primarily examined the dose enhancement factor by Au, it is also known that radiationinduced apoptosis is a significant component of radiation-induced cell death. Consequently, modulating the apoptotic response and thereby the radiosensitivity is of interest.(29-34) Therefore, in the current study, we investigated the dose-enhancing effect and apoptotic potential of gold nanoparticles in combination with single-dose clinical electron beams on B16F10 melanoma tumor-bearing mice. Materials and MethodsPreparatio...

Objective. Angiogenesis plays a part in the pathogenesis of rheumatoid arthritis (RA), and nanogold inhibits the activity of an angiogenic factor, vascular endothelial growth factor (VEGF). We therefore investigated whether intraarticular delivery of nanogold ameliorates collagen-induced arthritis (CIA) in rats.Methods. Binding of 13-nm nanogold to VEGF in human RA synovial fluid (SF) and its effects on RA SF-induced endothelial cell proliferation and migration were assessed. Nanogold was administered intraarticularly to rats with CIA before the onset of arthritis. Progression of CIA was monitored by measures of clinical, radiologic, and histologic changes. In addition, the microvessel density and extent of infiltrating macrophages as well as levels of tumor necrosis factor ␣ (TNF␣) and interleukin-1␤ (IL-1␤) in the ankle joints were determined.Results. Nanogold bound to VEGF in RA SF, resulting in inhibition of RA SF-induced endothelial cell proliferation and migration. Significant reductions in ankle circumference, articular index scores, and radiographic scores were observed in the nanogoldtreated rats with CIA compared with their control counterparts. In addition, the histologic score (of synovial hyperplasia, cartilage erosion, and leukocyte infiltration), microvessel density, macrophage infiltration, and levels of TNF␣ and IL-1␤ were also significantly reduced in the ankle joints of nanogold-treated rats.Conclusion. Our results are the first to demonstrate that intraarticular administration of nanogold ameliorates the clinical course of CIA in rats. Nanogold exerted antiangiogenic activities and subsequently reduced macrophage infiltration and inflammation, which resulted in attenuation of arthritis. These results demonstrate proof of principle for the use of nanogold as a novel therapeutic agent for the treatment of

Background-Growing evidence suggests that intramyocardial biomaterial injection improves cardiac functions after myocardial infarction (MI) in rodents. Cell therapy is another promising approach to treat MI, although poor retention of transplanted cells is a major challenge. In this study, we hypothesized that intramyocardial injection of self-assembling peptide nanofibers (NFs) thickens the infarcted myocardium and increases transplanted autologous bone marrow mononuclear cell (MNC) retention to attenuate cardiac remodeling and dysfunction in a pig MI model. Methods and Results-A total of 40 mature minipigs were divided into 5 groups: sham, MIϩnormal saline, MIϩNFs, MIϩMNCs, and MIϩMNCs/NFs. MI was induced by coronary occlusion followed by intramyocardial injection of 2 mL normal saline or 1% NFs with or without 1ϫ10 8 isolated autologous MNCs. NF injection significantly improved diastolic function and reduced ventricular remodeling 28 days after treatment. Injection of MNCs alone ameliorated systolic function only, whereas injection of MNCs with NFs significantly improved both systolic and diastolic functions as indicated by ϩdP/dt and ϪdP/dt (1214.5Ϯ91.9 and Ϫ1109.7Ϯ91.2 mm Hg/s in MIϩNS, 1693.7Ϯ84.7 and Ϫ1809.6Ϯ264.3 mm Hg/s in MIϩMNCs/NFs, respectively), increased transplanted cell retention (29.3Ϯ4.5 cells/mm 2 in MIϩMNCs and 229.4Ϯ41.4 cells/mm 2 in MIϩMNCs/NFs) and promoted capillary density in the peri-infarct area. Conclusions-We demonstrated that NF injection alone prevents ventricular remodeling, whereas cell implantation withNFs improves cell retention and cardiac functions after MI in pigs. This unprecedented combined treatment in a large animal model has therapeutic effects, which can be translated to clinical applications in the foreseeable future. (Circulation. 2010; 122[suppl 1]:S132-S141.)Key Words: biomaterials Ⅲ bone marrow mononuclear cells Ⅲ cardiac tissue engineering Ⅲ myocardial infarction C ongestive heart failure is a leading cause of death in the United States and other developed countries. The dominant cause of heart failure is loss of myocardium due to coronary artery disease and the limited regeneration potential of cardiomyocytes. Cardiac tissue engineering is a promising and actively developing area of research aiming to repair, replace, and regenerate the myocardium. Several studies have demonstrated the feasibility of this approach and indicated that direct injection of biomaterials into the infarcted myocardium may be beneficial in preventing deleterious remodeling and reducing cardiac dysfunction. [1][2][3][4] Previous studies using intramyocardial injection of self-assembling peptide nanofibers (NFs), a highly biocompatible 5,6 and biodegradable 7 material, have also revealed their therapeutic potentials for angiogenesis, controlled drug/growth factor release, cell delivery, and stem cell recruitment. [5][6][7][8][9][10] These results indicate that NFs may impact a broad spectrum of applications in myocardial tissue engineering.Cell therapy is another promising approach to h...

An intramyocardial microenvironment was created using nanofibers and VEGF for endogenous cardiac repair after infarction.