ABSTRACT
Objective:To construct superparamagnetic iron oxide nanoparticles targeting tumor angiogenesis and evaluate their potential value as contrast agent in magnetic resonance imaging (MRI) .Methods:Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles targeting tumor angiogenesis were prepared by using co-precipitation chemical method. Cyclic RGD(cRGD) containing the sequence of Arg-Gly-Asp were conjugated USPIO nanoparticles by using chemical conjugative method to prepare superparamagnetic imaging agent targeting tumor angiogenic vessles. The physical and chemical properties of cRGD-USPIO nanoparticles were detected. The specific binding capabilities of cRGD-USPIO and USPIO to human lung adenocarcinoma cells (A549) and human umbilical vein endothelial cells (HUVEC) were tested by Prussian blue staining. A549 xenografts were established in nude mice, then USPIO and cRGD-USPIO were injected though tail vein, and the MRI signal enhancement effect of cRGD-USPIO was evaluated.Results:We successfully prepared the cRGD-USPIO nanoparticles. Its core diameter was 5-10 nm and the average diameter was (43.97±10.10) nm and the quality saturation magnetic intensity was 59.94 A·m~2·kg~(-1). Cell-binding test suggested that cRGD-USPIO group showed strengthened positive staining. In vivo MRI experiments showed that signals of tumor were significantly reduced in cRGD-USPIO group than that in USPIO group (P<0.01). Conclusion:The constructed cRGD-USPIO nanoparticles can be developed as a potential tumor-specific MRI contrast agent for the early diagnosis of cancer.
ABSTRACT
Currently, animal somatic cell reprogramming into the induced pluripotent stem cell (iPS) is one of the hottest research target in the field of cell biology. We focused on the analysis of telomerase reverse transcriptase (TERT) gene expression during goat somatic fibroblasts reprogramming, and investigated the relationship between the expression of TERT and the pluripotency of reprogrammed cells. RNA samples of fetal tissues isolated from Guanzhong milk goat fetus, and the induced goat reprogramming cell clones were used to determine the relative expression levels of TERT by the real-time RT-PCR method. Goat embryonic fibroblasts (GEF) collected from the Guanzhong milk goat with normal karyotype were induced by 4 transcription factors to become reprogramming cells. The expression of TERT in reprogramming cells was detected by Real-time RT-PCR. The results showed that the expression of TERT in testis tissue was higher than that in epithelial tissues (P < 0.01). The expression level of TERT was higher in AP staining positive cells than that in AP staining negative cells (P < 0.01). This result indicated that TERT activity played an important role in cell reprogramming.