Yanli An

OxLDL-targeted iron oxide nanoparticles for in vivo MRI detection of perivascular carotid collar induced atherosclerotic lesions in ApoE-deficient mice.

Atherosclerotic disease is a leading cause of morbidity and mortality in developed countries, and oxidized LDL (OxLDL) plays a key role in the formation, rupture, and subsequent thrombus formation in atherosclerotic plaques. In the current study, anti-mouse OxLDL polyclonal antibody and nonspecific IgG antibody were conjugated to polyethylene glycol-coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, and a carotid perivascular collar model in apolipoprotein E-deficient mice was imaged at 7.0 Tesla MRI before contrast administration and at 8 h and 24 h after injection of 30 mg Fe/kg. The results showed MRI signal loss in the carotid atherosclerotic lesions after administration of targeted anti-OxLDL-USPIO at 8 h and 24 h, which is consistent with the presence of the nanoparticles in the lesions. Immunohistochemistry confirmed the colocalization of the OxLDL/macrophages and iron oxide nanoparticles. The nonspecific IgG-USPIO, unconjugated USPIO nanoparticles, and competitive inhibition groups had limited signal changes (p < 0.05). This report shows that anti-OxLDL-USPIO nanoparticles can be used to directly detect OxLDL and image atherosclerotic lesions within 24 h of nanoparticle administration and suggests a strategy for the therapeutic evaluation of atherosclerotic plaques in vivo.

Inhibition of heat-shock protein 90 sensitizes liver cancer stem-like cells to magnetic hyperthermia and enhances anti-tumor effect on hepatocellular carcinoma-burdened nude mice

Purpose To explore the thermoresistance and expression of heat-shock protein 90 (HSP90) in magnetic hyperthermia-treated human liver cancer stem-like cells (LCSCs) and the effects of a heat-shock protein HSP90 inhibitor 17-allylamino-17-demethoxgeldanamycin (17-AAG) on hepatocellular carcinoma-burdened nude mice. Methods CD90+ LCSCs were isolated by magnetic-activated cell sorting from BEL-7404. Spheroid formation, proliferation, differentiation, drug resistance, and tumor formation assays were performed to identify stem cell characteristics. CD90-targeted thermosensitive magnetoliposomes (TMs)-encapsulated 17-AAG (CD90@17-AAG/TMs) was prepared by reverse-phase evaporation and its characteristics were studied. Heat tolerance in CD90+ LCSCs and the effect of CD90@17-AAG/TMs-mediated heat sensitivity were examined in vitro and in vivo. Results CD90+ LCSCs showed significant stem cell-like properties. The 17-AAG/TMs were successfully prepared and were spherical in shape with an average size of 128.9±7.7 nm. When exposed to magnetic hyperthermia, HSP90 was up-regulated in CD90+ LCSCs. CD90@17-AAG/TMs inhibited the activity of HSP90 and increased the sensitivity of CD90+ LCSCs to magnetic hyperthermia. Conclusion The inhibition of HSP90 could sensitize CD90+ LCSCs to magnetic hyperthermia and enhance its anti-tumor effects in vitro and in vivo.

Analysis of in situ and ex vivo αVβ3 integrin expression during experimental carotid atherogenesis.

Objective Mural inflammation has been shown to contribute to the development of plaque, with the αVβ3 integrin highly expressed in atherosclerotic plaques. We herein examined αVβ3 integrin expression as a function of carotid atherosclerosis formation in the apolipoprotein E-deficient (apoE−/−) mouse. Methods and results Constrictive collars were placed around the left common carotid arteries of apo E−/− mice maintained on a high-fat diet (n = 14). Before and 21 days following collar placement, in vivo serial magnetic resonance imaging (MRI) measurements of the carotid aortic diameter were performed using a 7T magnetic resonance (MR) scanner. Near- infrared fluorescence (NIRF) imaging was performed (n = 6) using an in vivo imaging system 0–24 hours following administration of 1.0 nmol c(RGDyK)-Cy5.5 via the tail vein. A competition experiment was performed by the co-injection of a saturating dose of bicyclic RGD peptide H-Glu[cyclo(Arg-Gly-Asp-D-Tyr-Lys)]2 (n = 3). Following image acquisition and sacrifice at 24 hours after injection, carotid arteries were harvested for histological analyses. Neointima formation and arterial remodeling in the carotid arteries of apoE−/− mice were induced by the placement of a constrictive collar. Significantly greater fluorescent signals were obtained from constrictive collar left common carotid arteries as compared to uninvolved aortic segments in constrictive collar mice. Binding to stenotic lesions was efficiently blocked in competition experiments. Immunostaining confirmed the presence of mural αVβ3 integrin expression in macrophages in the neointima. Signal intensity increased in a macrophage density-dependent fashion in the stenotic segments. Conclusion Mural αVβ3 integrin expression, as determined using RGD-Cy5.5 near-infrared optical imaging, was increased in carotid arteries with constrictive collars in experimental mice. This expression can estimate the macrophage-bound inflammatory activity of atherosclerotic lesions.

Theranostic micelles based on upconversion nanoparticles for dual-modality imaging and photodynamic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is frequently metastatic once diagnosed and less likely to respond to curative surgery, emphasizing the need for the development of more sensitive and effective diagnostic and therapeutic strategies. Epithelial cell adhesion molecule (EpCAM) is deemed as the biomarker of cancer stem cells (CSCs), which are mainly responsible for the recurrence, metastasis and prognosis of HCC. In this study, we discuss the use of mitoxantrone (MX), an antitumor drug and a photosensitizer, for designing upconversion nanoparticle-based micelles grafted with the anti-EpCAM antibody, for dual-modality magnetic resonance/upconversion luminescence (MR/UCL)-guided synergetic chemotherapy and photodynamic therapy (PDT). The obtained micelles exhibit good biocompatibility, high specificity to HCC cells and superior fluorescent/magnetic properties in vitro. In vivo results demonstrate that the targeted micelles exhibited much better MR/UCL imaging qualities compared to the nontargeted micelles after the intravenous injection. More importantly, PEGylated UCNP micelles loaded with MX and grafted with anti-EpCAM antibody, denoted as anti-EpCAM-UPGs-MX, showcased the most effective synergetic antitumor efficacy compared with other treatment groups both in vitro and vivo. The remarkable antitumor effect, coupled with superior simultaneous dual-modality MR/UCL imaging as well as good biocompatibility and negligible toxicity, makes the UPG micelles promising for future translational research in HCC diagnosis and therapy.

Preparation of Folic Acid-Targeted Temperature-Sensitive Magnetoliposomes and their Antitumor Effects In Vitro and In Vivo

BackgroundOvarian cancer is a common gynecologic malignancy with poor prognosis, requiring innovative new therapeutic strategies. Temperature-controlled drug delivery to cancer cells represents a novel, promising, targeted treatment approach.ObjectiveWe prepared folate receptor-targeted thermosensitive liposomes wrapped with the HSP90 inhibitor 17-AAG and superparamagnetic material (17-AAG/MTSLs-FA), and tested the efficacy of these targeted magnetoliposomes in vitro and in vivo.MethodsMagnetic thermosensitive liposomes wrapped with 17-AAG were coprecipitated with Fe3O4 magnetic nanoparticles and prepared by a rotary evaporation method. Experiments were conducted with SKOV3 human ovarian cancer cells and MCF7 human breast carcinoma cells to evaluate the anti-tumor effects.Results17-AAG/MTSLs-FA prepared in this study met the basic requirements for therapeutic application. The preparation method is relatively simple and the raw materials are readily available. The product exhibited strong magnetism, high encapsulation efficiencies, and satisfactory performance. The liposomes combined with hyperthermia significantly inhibited the proliferation of SKOV3 cells and induced apoptosis. Experiments using a mouse subcutaneous model as well as an ascites tumor xenograft model indicated that 17-AAG/MTSLs-FA was stable in vivo and effectively targeted tumor tissues expressing the folate receptor.ConclusionsFolic acid-conjugated 17-AAG magnetic thermosensitive liposomes in combination with an alternating magnetic field for heating can achieve a synergistic anti-tumor effect of chemotherapy and heat treatment, potentially offering a new method for ovarian cancer treatment.

Noninvasive evaluation of the migration effect of transplanted endothelial progenitor cells in ischemic muscle using a multimodal imaging agent

Background Endothelial progenitor cells (EPCs) play an important role in repairing ischemia tissues. However, the survival, migration and therapeutic efficacy of EPCs after transplantation need to be better understood for further cell therapy. Purpose This study investigated the migration effect of EPCs labeled with a multimodal imaging agent in a murine ischemic hindlimb model, using magnetic resonance imaging (MRI) and optical imaging after transplantation. Methods EPCs derived from mouse bone marrow were labeled with a multimodal imaging agent and were administered through intracardiac delivery to mice with ischemic hindlimbs. The injected EPCs and their migration effect were observed via MRI and optical imaging in vivo, and then compared to a reference standard based on histological data. The quantification of gadolinium in tissue samples was done using inductively coupled plasma mass spectrometry (ICP-MS). Results Using in vivo MRI and optical imaging, the labeled EPCs were observed to migrate to ischemic muscle on days 3–5 after injection, while ex vivo, the EPCs were observed in the capillary vessels of the injured tissue. There were significant linear correlations between the Gd contents measured using ICP-MS in samples from the ischemic hindlimbs and livers and T1 relaxation times calculated using MRI, as well as the average fluorescence signal intensities recorded in optical images (T1 relaxation time: r=0.491; average signal from optical imaging: r=0.704, P<0.01). EPC treatment upregulated the levels of C-X-C chemokine receptor 4 and vascular endothelial growth factor (VEGF) receptor 2 and enhanced the expression of stromal cell-derived factor-1 and VEGF. Conclusion Transplanted EPCs can be monitored with noninvasive MRI and optical imaging in vivo and were found to enhance the paracrine secretion of angiogenic factors.

In vivo MR imaging of folate-receptor expression with the folate-specific nanospheres in a C6 glioblastoma model

Abstract Purpose: To assess the ability of magnetic albumin nanospheres conjugated with folate (FA-MAN) to provide FR-specific enhancement of C6 glioblastoma on magnetic resonance (MR) images. Procedures: Active targeting effect of magnetic albumin nanospheres conjugated with folate (FA-MAN) was evaluated based on MR images and histopathological analysis. MR imaging of subcutaneously transplanted C6 glioblastomas was performed after intravenous injection of FA-MAN, non-targeted (magnetic albumin nanospheres, MAN) and FA-inhibited (magnetic albumin nanospheres conjugated with folate plus folate, FA-MAN + FA) agents at designated time points. The T2 relaxation times in tumors were compared among different treatment groups and were correlated with histopathological findings. Prussian blue staining and in vivo toxicology assay were also performed simultaneously. Results: Upon MR imaging in vivo, T2 relaxation time of the tumor sites in the group administrated with FA-MAN (T2 is 49 ms, 46 ms and 45 ms at 24 h, 48 h and 72 h, respectively) has statistical difference compared to those in the groups of MAN (T2 is 56 ms, 56 ms and 61 ms at 24 h, 48 h and 72 h, respectively) and FA-MAN + FA nanospheres (T2 is 56 ms, 57 ms and 56 ms at 24 h, 48 h and 72 h, respectively). Prussian blue-stained results demonstrated that more iron particles accumulated in the tumors of the targeted group than those of the other groups. Toxicology assay showed that no noticeable body weight losses were observed after monitoring 31 days, and the results of routine blood parameters, liver and kidney function biomarkers also demonstrated that the nanoshperes did not influence the respectively physiological index. Besides, no obvious pathological injuries on the major organs were examined. Conclusion: Folate-conjugated magnetic albumin nanospheres were more effective in targeting C6 glioblastoma in vivo.