Methotrexate-conjugated quantum dots: synthesis,characterisation and cytotoxicity in drug resistant cancer cells

Methotrexate (MTX), a folic acid derivative, is a potent anticancer used for treatment of different malignancies, but possible initiation of drug resistance to MTX by cancer cells has limited its applications. Nanoconjugates (NCs) of MTX to quantum dots (QDs) may favour the cellular uptake via folate receptors (FRs)-mediated endocytosis that circumvents the efflux functions of cancer cells. We synthesised MTX-conjugated l-cysteine capped CdSe QDs (MTX-QD nanoconjugates) and evaluated their internalisation and cytotoxicity in the KB cells with/without resistancy to MTX. The NCs were fully characterised by high resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and optical spectroscopy. Upon conjugation with MTX, the photoluminescence (PL) properties of QDs altered, while an obvious quenching in PL of QDs was observed after physical mixing. The MTX-QD nanoconjugates efficiently internalised into the cancer cells, and induced markedly high cytotoxicity (IC₅₀, 12.0?µg/mL) in the MTX-resistant KB cells as compared to the free MTX molecules (IC₅₀,105.0?µg/mL), whereas, these values were respectively about 7.0 and 0.6?µg/mL in the MTX-sensitive KB cells. Based on these findings, the MTX-QD nanoconjugates are proposed for the targeted therapy of MTX-resistant cancers, which may provide an improved outcome in the relapsed FR-overexpressing cancers.     

CIK细胞对人肺腺癌AS49／DDP耐药细胞株的抗增殖及诱导凋亡形态学研究

目的研究多种细胞因子诱导的杀伤细胞（CIK）对A549／DDP肺癌耐药细胞株的抗增殖和诱导凋亡作用。方法应用细胞计数法设计细胞浓度,通过相差显微镜下观察CIK细胞对A549／DDP肺癌耐药细胞株形态学影响。结果随着CIK细胞与肺癌细胞效靶比增加及作用时间延长,抑制率明显增强,CIK细胞作用于肺癌细胞24h后,形态学观察肺癌细胞发生凋亡或坏死。结论体外制备的CIK细胞对肺癌耐药细胞株A549／DDP具有抑制增殖和促进凋亡作用。     

Measurement of accumulation of semiconductor nanocrystal quantum dots by pimephales promelas

As the production and use of nanomaterials increases, it is important to understand their environmental and biological fate. Because their unmatched chemical, physical, and optical properties make them useful in a wide variety of applications including biomedical imaging, photo-voltaics, and light emitting diodes, the use of semiconductor nanocrystals such as quantum dots (QDs) is increasing rapidly. Although QDs hold great potential in a wide variety of industrial and consumer applications, the environmental implications of these particles is largely unexplored. The nanocrystal core of many types of QDs contains the toxic metal cadmium (Cd), so possible release of Cd from the QD core is cause for concern. Because many types of QDs are miscible in water, QD interactions with aquatic organisms and their environment require more attention. In the present study we used fluorometry to measure time and dose dependent uptake, accumulation, and post-exposure clearance of accumulated QDs in the gut tract by the aquatic vertebrate Pimephales promelas. By using fluorometry, we were able to measure accumulated QD concentrations. To our knowledge, this is the first reported attempt to quantify accumulated QDs in an organism and is an important step in understanding the interactions among QDs in aquatic organisms and environments.     

量子点荧光探针用于汉坦病毒重组抗原的检测

目的应用量子点荧光探针对汉坦病毒（Hantavirus,HV）重组抗原进行检测。方法合成水溶性量子点荧光纳米颗粒,并在其表面修饰G蛋白和anti-HV抗体作为量子点荧光探针,对HV重组抗原进行检测并优化检测条件。结果量子点与抗体的最佳偶联条件：pH 6.0、反应时间2 h、抗体浓度为20μg/ml。用本方法检测HV重组抗原的最低检测值为5 ng/ml。结论该探针能有效的识别HV抗原,且操作简便快速,为HV重组抗原的检测和肾出血热综合征的诊断提供了新方法。     

The antitumour effects of eudesmin on lung cancer by inducing apoptosis via mitochondria-mediated pathway in the tumour cells

Context: Limonoids possess broad range of biological activities, including antitumour, antimicrobial and antioxidant activities, etc. Eudesmin (EDN) is a type of limonoid which also possesses various activities. However, there is no report on the antitumour lung cancer (LC) activities of this compound.

Objective: The present study investigates the antitumour effects of EDN and its potential molecular mechanisms.

Materials and methods: The in vitro antitumour effects of EDN on LC A549 cells were evaluated by using MTT assay. The in vivo antitumour effects were investigated on a xenograft athymic nude mouse model. The mice were administered orally with EDN (10, 20 and 40?mg/kg) once daily for 28 days. Effects of EDN on apoptosis-related or signalling proteins (Bcl-2, Bax, caspase-3, caspase-9, P53, Akt and JNK) were assayed by western blot analysis.

Results: EDN showed significant inhibitory effects on the growth of LC A549 cells in vitro with the half maximal inhibitory concentration (IC₅₀) of 18.3?μM. By treating with EDN (10, 20 and 40?μM), expression of caspase-3, caspase-9, Bax, P53 and phosphorylated JNK in A549 cells were significantly upregulated, whereas expression of Bcl-2 and Akt phosphorylation were significantly down-regulated. Interestingly, EDN-induced apoptosis could be attenuated by JNK inhibitor. In addition, in vivo experiments also indicated EDN (10, 20 and 40?mg/kg) had significant antitumour effects (p?Conclusions: Overall, the results indicated that EDN possesses significant antitumour effects on LC and the possible mechanism might be related to induction of mitochondria-mediated apoptosis.     

Doxorubicin-conjugated D-glucosamine- and folate- bi-functionalised InP/ZnS quantum dots for cancer cells imaging and therapy

Nanoscaled quantum dots (QDs), with unique optical properties have been used for the development of theranostics. Here, InP/ZnS QDs were synthesised and functionalised with folate (QD-FA), D-glucosamine (QD-GA) or both (QD-FA-GA). The bi-functionalised QDs were further conjugated with doxorubicin (QD-FA-GA-DOX). Optimum Indium to fatty acid (In:MA) ratio was 1:3.5. Transmission electron microscopy (TEM) micrographs revealed spherical morphology for the QDs (11?nm). Energy-dispersive spectroscopy (EDS) spectrum confirmed the chemical composition of the QDs. MTT analysis in the OVCAR-3 cells treated with bare QDs, QD-FA, QD-GA, QD-FA-GA and QD-FA-GA-DOX (0.2?mg/mL of QDs) after 24?h indicated low toxicity for the bare QDs and functionalised QDs (about 80–90% cell viability). QD-FA-GA-DOX nanoparticles elicited toxicity in the cells. Cellular uptake of the engineered QDs were investigated in both folate receptor (FR)-positive OVCAR-3 cells and FR-negative A549 cells using fluorescence microscopy and FACS flow cytometry. The FA-functionalised QDs showed significantly higher uptake in the FR-positive OVCAR-3 cells, nonetheless the GA-functionalised QDs resulted in an indiscriminate uptake in both cell lines. In conclusion, our findings indicated that DOX-conjugated FA-armed QDs can be used as theranostics for simultaneous imaging and therapy of cancer.     

Cytotoxic effect of CdSe quantum dots on mouse embryonic development

AIM: The aim of this study was to examine the cytotoxic effect of quantum dots (QD), a novel luminescent material, on early post-implantation embryonic development. METHODS: Mouse blastocysts were incubated in medium with or without CdSe-core QD (250 or 500 nmol/L) for 24 h. Cell apoptosis was analyzed by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling assay and Annexin V/propidium iodide staining, and proliferation was investigated by dual differential staining. Pre-implantation and post-implantation development was assessed by in vitro and in vivo analyses, respectively. RESULTS: The apoptotic staining analysis showed that CdSe-core QD induced apoptosis in mouse blastocysts in a dose-dependent manner. Pretreatment of blastocysts with CdSe-core QD inhibited cell proliferation, primarily in the inner cell mass. CdSe-core QD also inhibited post-implantation embryonic development; fewer CdSe-core QD-pretreated blastocysts reached the later stages of development compared to the controls. The pre-implantation development of morulas into blastocysts was also inhibited by CdSe-core QD. Furthermore, CdSe-core QD at 500 nmol/L were associated with resorption of post-implantation blastocysts and a decrease in fetal weight. The cytotoxicity of CdSe QD in embryonic development was significantly reduced by the addition of a ZnS coating. CONCLUSION: Our results show that CdSe-core QD induce apoptosis in mouse blastocysts, inhibit cell proliferation, retard early post-implantation blastocyst development, and increase early-stage blastocyst death in vitro and in vivo.     

Evidence of three-level trophic transfer of quantum dots in an aquatic food chain by using bioimaging

Abstract

In this study, we demonstrated the three-level trophic transfer of quantum dots (QDs) within the aquatic food chain. Using bioimaging, we observed QD transfer from protozoa (Astasia longa) to zooplankton (Moina macrocopa) to fish (Danio rerio). Bioimaging is an effective tool that can improve our understanding of the delivery of nanomaterials in vivo. Measurement with an intravital multiphoton laser scanning microscope visually proved the transfer of QDs from the first to the second and the second to the third levels. As QDs may be passed from lower organisms to humans via the food chain, our findings have implications for the safety of their use.     

Penetration of intact skin by quantum dots with diverse physicochemical properties.

Skin is the largest organ of the body and is a potential route of exposure to engineered nanomaterials, but the permeability of the skin to these nanomaterials is unknown. We selected commercially available quantum dots (QD) of two core/shell sizes and shapes and three different surface coatings to determine if QD could penetrate intact skin in a size- or coating-dependent manner. Spherical 4.6 nm core/shell diameter QD 565 and ellipsoid 12 nm (major axis) by 6 nm (minor axis) core/shell diameter QD 655 with neutral (polyethylene glycol), anionic (carboxylic acids) or cationic (polyethylene glycol-amine) coatings were topically applied to porcine skin in flow-through diffusion cells at an occupationally relevant dose for 8 h and 24 h. Confocal microscopy revealed that spherical QD 565 of each surface coating penetrated the stratum corneum and localized within the epidermal and dermal layers by 8 h. Similarly, polyethylene glycol- and polyethylene glycol-amine-coated ellipsoid QD 655 localized within the epidermal layers by 8 h. No penetration of carboxylic acid-coated QD 655 was evident until 24 h, at which time localization in the epidermal layers was observed. This study showed that quantum dots of different sizes, shapes, and surface coatings can penetrate intact skin at an occupationally relevant dose within the span of an average-length work day. These results suggest that skin is surprisingly permeable to nanomaterials with diverse physicochemical properties and may serve as a portal of entry for localized, and possibly systemic, exposure of humans to QD and other engineered nanoscale materials.     

西瑞香素对肺癌A549细胞侵袭及迁移能力的影响

目的探讨西瑞香素对肺癌A549细胞侵袭及迁移能力的影响。方法通过Transwell小室分析西瑞香素对肺癌A549细胞侵袭能力的影响;划痕实验检测西瑞香素对肺癌A549细胞迁移能力的影响;Western blotting检测西瑞香素作用于A549细胞后MMP-2、MMP-9侵袭相关蛋白的表达。结果 Transwell小室实验结果提示,西瑞香素对A549细胞侵袭能力有抑制作用;划痕实验结果提示,西瑞香素对A549细胞迁移能力有抑制作用;Western blotting结果提示,西瑞香素抑制MMP-2、MMP-9侵袭相关蛋白的表达。随着药物浓度增加,MMP-2、MMP-9表达减少,具有剂量依赖性。结论西瑞香素对A549细胞体外侵袭及迁移有抑制作用,这种作用与抑制MMP-2、MMP-9表达有关。     

miR-552通过PTEN/AKT信号通路促进非小细胞肺癌A549细胞的恶性生物学行为

目的 探讨miR-552通过调控PTEN/AKT信号通路促进人非小细胞肺癌A549细胞的恶性生物学行为及其相关机制。方法 通过qRT-PCR检测人肺癌组织样本和人非小细胞肺癌A549细胞系中miR-552、PTEN mRNA的表达情况;通过Western blotting检测PTEN、AKT、p-AKT蛋白的表达情况;通过CCK-8检测miR-552表达对A549细胞增殖能力的影响;通过Transwell小室检测miR-552表达对A549细胞迁移和侵袭能力的影响;通过流式细胞术检测miR-552表达对A549细胞凋亡能力的影响。结果 miR-552在肺癌组织和A549细胞中的表达显著上调。过表达miR-552可显著促进A549细胞的增殖、迁移和侵袭,并抑制细胞凋亡,而抑制其表达则结果相反。与癌旁组织相比,肺癌组织中PTEN表达显著下调。过表达miR-552可下调PTEN蛋白表达,上调p-AKT蛋白表达,对AKT蛋白无影响,而抑制其表达则结果相反。结论 miR-552可能通过PTEN/AKT信号通路促进人非小细胞肺癌A549细胞的恶性生物学行为。     

Quantum dots in cancer therapy

Introduction: Quantum dots (QDs) are nanometer-size luminescent semiconductor nanocrystals. Their unique optical properties, such as high brightness, long-term stability, simultaneous detection of multiple signals and tunable emission spectra, make them appealing as potential diagnostic and therapeutic systems in the field of oncology.

Areas covered: This paper summarizes the recent progress of promising applications of QDs in cancer therapy, from the following aspects: identifying molecular targets, sentinel lymph-node mapping, surgical oncology, drug delivery and tracking, fluorescence resonance energy transfer and photodynamic therapy, personalized and predictive medicine, and multifunctional design and development. Limitations and toxicity issues related to QDs in living organisms are also discussed.

Expert opinion: Bioconjugated QDs can be used to identify potential molecular biomarkers for cancer diagnosis, treatment and prognosis. They may allow the surgeon to map sentinel lymph nodes and perform a complete surgical resection. Their unique optical properties make them ideal donors of fluorescence resonance energy transfer and photodynamic therapy studies. Multifunctional QDs have become effective materials for synchronous cancer diagnosis, targeting and treatment. For QDs, toxicity remains the major barrier to clinical translation.     

Nanoparticles attenuate P-glycoprotein/MDR1 function in A549 human alveolar epithelial cells

P-glycoprotein/MDR1 (P-gp) is a well-characterised membrane transporter relevant in drug disposition and multi-drug resistance. In this study, we aimed to investigate how far nanoparticulates impair the function of the P-gp transport system and which particle properties govern these interactions.Expression and function of P-gp was confirmed in A549 cell monolayers. Rhodamine 123 (Rh123) release studies were carried out in the presence of known inhibitors of P-gp function (i.e., cyclosporine A and verapamil), under ATP depletion (NaN₃/DOG) and after acute exposure to nanoparticles (NPs) with different surface modifications, ζ-potentials and sizes (plain, carboxylated, and amine- and sulphate-modified). The cytotoxic potential of NPs on A549 monolayers was evaluated by MTT assay. The effects on P-gp protein level, after incubation with NPs, were investigated by Western blot analysis of A549 cell lysate and supernatant.Cellular retention of Rh123 was significantly (P < 0.05) increased in the presence of carboxylated (100 nm), amine- and sulphate-modified NPs. A slight, but not significant, decrease in Rh123 release was also observed for plain latex and carboxylated (500 nm) NPs. The MTT assay demonstrated that most NPs caused only marginal levels of cytotoxicity (78-88% cell viability); the positively charged amine-NPs, however, were considerably more cytotoxic. Western blot showed that NPs did not cause any cell membrane disruption.Our findings suggest that nanomaterials can attenuate membrane transporter function depending on their size and surface properties and hence might influence the disposition of xenobiotics as well as endogenous substrates.     

Determination of ketoprofen based on its quenching effect in the fluorescence of quantum dots

Ketoprofen is a potent nonsteroidal anti-inflammatory drug used for the treatment of inflammatory diseases and musculoskeletal injuries. Taking into account the increasing consumption of this drug, it is important to develop a rapid, easy, and reliable analytical strategy for its quality control. In this work, we present a novel method for ketoprofen determination, based on its quenching effect produced in the fluorescence of CdTe quantum dots modified by mercaptopropionic acid. Under optimized conditions, the method was linear in the range of 7.5–100 μg/mL, with a detection limit of 2.3 μg/mL and relative standard deviations lower than 2%. It was applied to the determination of ketoprofen in pharmaceutical formulations, obtaining results in good agreement with those provided by the manufacturer.     

夏枯草乙醇提取物体外诱导肺癌细胞A549凋亡的研究

目的探讨夏枯草乙醇提取物对人肺癌细胞系A549细胞的增殖、迁移、细胞周期及凋亡的影响。方法不同质量浓度夏枯草提取物作用于人肺癌A549细胞,采用MTT比色法、细胞划痕实验等检测其对肿瘤细胞的生长及迁移的抑制作用,应用流式细胞术检测细胞增殖周期及凋亡率的变化情况,并使用Annexin-V FITC和PI双染试剂盒进行凋亡分析。结果一定质量浓度的夏枯草提取物可明显抑制肺癌细胞的增殖和迁移,并呈量效和时效关系,可诱导细胞发生G0/G1期或G2/M期细胞周期阻滞,且Sub G1峰比例明显上升,在低、中质量浓度(1.0和2.0mg·L-1)时以晚期凋亡为主,在高质量浓度(4.0mg·L-1)时主要发生早期凋亡。结论夏枯草提取物可抑制肺癌A549细胞的增殖和迁移,改变细胞周期,诱导肿瘤细胞凋亡。     

Gut microbiota and lipid metabolism alterations in mice induced by oral cadmium telluride quantum dots

The potential toxicity of cadmium-containing quantum dots (QDs) has received much attention because of increasing biomedical applications. However, little has been known about how cadmium telluride (CdTe) QDs influence the gut microbiota and lipid metabolism. In this study, mice were exposed orally to CdTe QDs (200 μL of 0.2, 2, 20 or 200 μm ; twice per week) for 4 weeks. The oral experiments showed CdTe QD exposure led to a decrease of the Firmicutes/Bacteroidetes (F/B) ratio of gut microbiota, which highly negatively correlated with the low-density lipoprotein (LDL), triglyceride (TG) and total cholesterol (TC) levels in serum. In addition, the low-dose (0.2 and 2 μm ) CdTe QDs significantly increased the diversity of gut microbiota, and did not elevate the LDL, TG and TC levels in serum. The medium dose (20 μm ) of CdTe QDs caused the biggest decrease of the F/B ratio, so it significantly increased the LDL, TG and TC levels compared with the control. Furthermore, high-dose (200 μm ) CdTe QDs caused various toxicities in the histopathology of liver and intestine, liver function and intestinal immunity, but did not significantly lead to changes of the LDL, TG and TC levels in serum. This study demonstrates that high-dose oral CdTe QDs mainly lead to tissue damage of the liver and intestine, while the medium and low doses of oral CdTe QDs induce shifts of gut microbiota structure, which are associated with blood lipid levels.     

姜黄素诱导人肺腺癌A549细胞脱落凋亡作用的研究

目的检测姜黄素诱导人肺腺癌细胞(A549)脱落凋亡的作用。方法采用DNA ladder法,流式细胞仪(FCM)技术结合PI及AnnexinV-FITC双标记染色试验方法及W estern-b lot法观察姜黄素是否能诱导A549脱落凋亡。结果A549细胞具有抗脱落凋亡的特性,而10μmol.L-1的姜黄素即可引起悬浮培养的A549细胞发生脱落凋亡。结论姜黄素可诱导人肺腺癌细胞(A549)脱落凋亡。     

MiR-342 attenuates lipopolysaccharide-induced acute lung injury via inhibiting MAPK1 expression

Micro RNA (miRNA) and mitogen-activated protein kinase (MAPK) are reported as the crucial regulators of inflammatory responses in acute lung injury (ALI). This study will explore the role of the miR-342/MAPK1 axis in regulation of lipopolysaccharide (LPS)-induced ALI. We found that miR-342 was down-regulated in LPS-induced A549 cells compared with the control group with DMSO, accompanied by elevated inflammatory cytokines and apoptosis. Over-expression of miR-342 reduced LPS-induced inflammatory responses and apoptosis in LPS-stimulated A549 cells, and had a protective role in LPS-treated mice with ALI by decreasing levels of inflammatory cytokines, improving survival of mice with ALI, and ameliorating the lung permeability. Dual-luciferase reporter gene assay demonstrated that miR-342 regulated the expression of MAPK1 by directly targeting its 3′ untranslated region (3′-UTR). Mechanistically, MAPK1 silencing abrogated LPS-induced inflammatory injury in A549 cells, and partially enhanced the protective effect of miR-342. Therefore, miR-342 attenuates LPS-induced ALI by targeting MAPK1 expression, thereby protecting against A549 cell injury induced by LPS and lung injury of mice with ALI.     

DNA damage in BV‐2 cells: An important supplement to the neurotoxicity of CdTe quantum dots

Microglial cells are resident immune cells in the central nervous system. Activation of microglia as induced by CdTe quantum dots (QDs) can trigger damage to neurons. To quantify the intracellular QDs, we monitored the intracellular Cd concentration in the QD‐exposed mouse microglial cells (BV‐2 cell line). The extent of cell injury at different times correlated with the Cd concentration in cells at that time. In addition to Cd ion detection, we also monitored the intracellular fluorescence of the QDs. More QDs accumulated in the nucleus than in the cytoplasm. Comet assays confirmed that QDs induce DNA damage. However, DNA cannot interact with QDs, so the DNA damage was not caused by CdTe QDs adducts to DNA but by the increase of the Cd ion concentration and the secondary oxidative damage. In addition to DNA damage, biofilm injury and endogenous reduced glutathione depletion were also apparent in QD‐exposed BV‐2 cells. These changes can be prevented or even reversed by exogenous reduced glutathione administration.