A simple, straightforward, and reproducible strategy for the construction of a near-infrared (NIR) fluorescence nanoprobe was developed by coating CuInS2/ZnS quantum dots (CIS/ZnS QDs) with a novel amphiphilic bioconjugate. The amphiphilic bioconjugate with a tailor-designed structure of bovine serum albumin (BSA) as the hydrophilic segment and poly(ε-caprolactone) (PCL) as the hydrophobic part was fabricated by chemical coupling the hydrophobic polymer chain to BSA via the maleimide–sulfhydryl reaction. By incorporating CIS/ZnS QDs into the hydrophobic cores of the self-assembly of BSA-PCL conjugate, the constructed NIR fluorescence nanoprobe exhibited excellent fluorescent properties over a wide pH range (pH 3–10) and a good colloidal stability in PBS buffer (pH = 7.4) with or without 10% fetal bovine serum. The presence of the outer BSA shell effectively reduced the nonspecific cellular binding and imparted high biocompatibility and low-toxicity to the probe. Moreover, the NIR fluorescence nanoprobe could be functionalized by conjugating cyclic Arg-Gly-Asp (cRGD) peptide, and the decorated nanoprobe was shown to be highly selective for targeted integrin αvβ3-overexpressed tumor cell imaging. The feasibility of the constructed NIR fluorescence probe in vivo application was further investigated and the results demonstrated its great potential for in vivo imaging. This developed protocol for phase transfer of the CIS/ZnS QDs was universal and applicable to other nanoparticles stabilized with hydrophobic ligands.
Cancer is a major disease currently endangering the entire world population. Morbidity and mortality have increased substantially during recent decades. Radiotherapy is a primary treatment for malignant tumors, however side‑effects and tumor cell resistance to ionizing radiation reduce the efficacy of radiotherapy. In recent years, non‑thermal plasma (NTP) technology been used to treat cancer. In this study, we investigated the toxic effects of NTP on normal cells and tumor cells. We explored the inhibitory effect of NTP on tumor cell proliferation and evaluated the radiation‑sensitizing effects of NTP on tumor cells and its mechanisms. In short, we examined the effect of NTP‑combined radiation on proliferation, the cell cycle, apoptosis and DNA damage in normal and cancer cells. We found that NTP inhibited proliferation and induced apoptosis in tumor cells. NTP was more lethal to tumor cells than to normal cells. We found promising synergies of NTP with radiotherapy on cancer cells owing to their combined cytotoxic effects by generating ROS, inducing cell cycle arrest and apoptosis. NTP may be a new candidate for the treatment of cancer.
Radiation treatment for nasopharyngeal carcinoma (NPC) is common and effective. However, local recurrence occurs frequently. Endostar, a novel recombinant human endostatin, is an antiangiogenic drug with a potent antitumor effect. The present study aimed to observe and explore the radiosensitization effects of Endostar on NPC and its underlying mechanism. The NPC subcutaneous transplantation tumor animal model was established to evaluate the antitumor activity of Endostar combined with radiation (Endostar + radiation) treatment compared with monotherapy (Endostar or radiation). Tumor growth and tumor weight were measured to evaluate the antitumor effect. The level of vascular endothelial growth factor (VEGF) and microvessel density (MVD) were measured using immunohistochemical staining of the tumor tissues. Significant antitumor activity was found in the Endostar + radiation group. The tumor inhibition rates of Endostar, radiation and Endostar + radiation were 27.12, 60.45 and 86.11%, respectively. The VEGF levels in the tumor tissue in the Endostar + radiation group were lower than those in the radiation and control groups. The MVD in the tumor tissues in the Endostar + radiation group was 12.2±2.5, lower than that in the Endostar (29.3±3.4), radiation (23.5±3.6) and control (44.7±5.1) groups. These results suggest that Endostar increases the radiation sensitivity of NPC-transplanted tumors in nude mice by lowering VEGF expression. In this study, the NPC animal model was established, which reflects the efficacy of clinical combination therapies and the combination of Endostar and radiation. The mechanisms of the combination therapies should be further investigated using this model.
1 December 2021 in Ecotoxicology and Environmental Safety
Tritium is a water-soluble hydrogen isotope that releases beta rays during decay. In nature, tritium primarily exists as tritiated water (HTO), and its main source is nuclear power/processing plants. In recent decades, with the development of nuclear power industry, it is necessary to evaluate the impact of tritium on organisms. In this study, fertilized zebrafish embryos are treated with different HTO concentrations (3.7 × 103 Bq/ml, 3.7 × 104 Bq/ml, 3.7 × 105 Bq/ml). After treatment with HTO, the zebrafish embryos developed without evident morphological changes. Nevertheless, the heart rate increased and locomotor activity decreased significantly. In addition, RNA-sequencing shows that HTO can affect gene expressions. The differentially expressed genes are enriched through many physiological processes and intracellular signaling pathways, including cardiac, cardiovascular, and nervous system development and the metabolism of xenobiotics by cytochrome P450. Moreover, the concentrations of thyroid hormones in the zebrafish decrease and the expression of thyroid hormone-related genes is disordered after HTO treatment. Our results suggest that exposure to HTO may affect the physiology and behaviors of zebrafish through physiological processes and intracellular signaling pathways and provide a theoretical basis for ecological risk assessment of tritium.
The effects of ionizing radiation on the reproductive system have always been a matter of great interest. Both artificial and naturally occurring ionizing radiation can directly or indirectly affect the reproductive system via the introduction of DNA single-strand and double-strand breaks, the excitation of water molecules, and the generation of free radicals. In order to quantitatively investigate the effects of ionizing radiation on reproductive function, 60Co γ irradiation was applied on a model organism, Caenorhabditis elegans (C. elegans). The egg-laying and embryo-hatching activities were observed for the parent (F0) and the first 2 progeny (F1 and F2) generations. The incidence rate of ovipositor malformation was also recorded. Acridine orange was used to detect the number of apoptotic germ cells. With the above metrics, the effects of 60Co γ irradiation on the reproductive function of C. elegans were systematically evaluated. The results showed that the postirradiation egg-laying and embryo-hatching activities of the F0 generation were increasingly suppressed by increasing doses of 60Co γ irradiation. Those of the F1 generation showed a trend toward recovery although also suppressed by the radiation to the F0 generation compared with the control. Those activities were restored to normal or near-normal levels for the F2 generation. The incidence rate of ovipositor malformation was greatly increased by 60Co γ irradiation according to radiation doses. Gamma irradiation by 60Co also substantially induced germ cell apoptosis, and the apoptosis rate increased with increasing radiation doses. Therefore, 60Co γ irradiation affects the reproductive function of C. elegans. The suppression on its reproductive function increases with increasing radiation doses. The reproductive functions of progeny generations are also affected and weakened.