Mingqi Zhao

Multifunctional selenium nanoparticles as carriers of HSP70 siRNA to induce apoptosis of HepG2 cells

Small interfering RNA (siRNA) as a new therapeutic modality holds promise for cancer treatment, but it is unable to cross cell membrane. To overcome this limitation, nanotechnology has been proposed for mediation of siRNA transfection. Selenium (Se) is a vital dietary trace element for mammalian life and plays an essential role in the growth and functioning of humans. As a novel Se species, Se nanoparticles have attracted more and more attention for their higher anticancer efficacy. In the present study, siRNAs with polyethylenimine (PEI)-modified Se nanoparticles (Se@PEI@siRNA) have been demonstrated to enhance the apoptosis of HepG2 cells. Heat shock protein (HSP)-70 is overexpressed in many types of human cancer and plays a significant role in several biological processes including the regulation of apoptosis. The objective of this study was to silence inducible HSP70 and promote the apoptosis of Se-induced HepG2 cells. Se@PEI@siRNA were successfully prepared and characterized by various microscopic methods. Se@PEI@siRNA showed satisfactory size distribution, high stability, and selectivity between cancer and normal cells. The cytotoxicity of Se@PEI@siRNA was lower for normal cells than tumor cells, indicating that these compounds may have fewer side effects. The gene-silencing efficiency of Se@PEI@siRNA was significantly much higher than Lipofectamine 2000@siRNA and resulted in a significantly reduced HSP70 mRNA and protein expression in cancer cells. When the expression of HSP70 was diminished, the function of cell protection was also removed and cancer cells became more sensitive to Se@PEI@siRNA. Moreover, Se@PEI@siRNA exhibited enhanced cytotoxic effects on cancer cells and triggered intracellular reactive oxygen species, and the signaling pathways of p53 and AKT were activated to advance cell apoptosis. Taken together, this study provides a strategy for the design of an anticancer nanosystem as a carrier of HSP70 siRNA to achieve synergistic cancer therapy.

Molecular Identification and Epidemiological Features of Human Adenoviruses Associated with Acute Respiratory Infections in Hospitalized Children in Southern China, 2012-2013.

Background Acute respiratory infections (ARI) are the major worldwide health problem associated with high morbidity and mortality rates. Human adenovirus (HAdV) is one of the most common pathogens associated with viral ARI, and thus calls for specific diagnosis and better understanding of the epidemiology and clinical characteristics. Methods Total 4,130 children with ARI requiring hospitalization from 2012 to 2013 were retrospectively studied. Throat swab specimens were collected from each patient. Fluorescence Quantitative PCR was performed to detect adenovirus as well as other common ARI-related pathogens. The seven HAdV hypervariable regions (HVRs) of the hexon gene from fifty-seven HAdVs-positive samples collected in the seasonal peaks were sequenced. Phylogenetic analysis of HVRs was also conducted to confirm the molecular types and genetic variation. In addition, epidemiological features and co-infection with other human respiratory pathogens were investigated and analyzed. Results Of 4,130 hospitalized pediatric patients tested, the positive rates of respiratory syncytial virus (RSV), Mycoplasma pneumoniae (MP), and HAdV were 13.7%, 13.2%, and 12.0%, respectively. The HAdV positive patients accounted for 7.9%, 17.2%, 17.5% and 10.7% in age groups <1, 1–3, 3–6 and 6–14 years, respectively. Eighty-four HAdV positive children were co-infected with other respiratory pathogens (84/495, 17.0%). The most common co-infection pathogens with HAdV were MP (57.1%) and Human Bocavirus (HBoV) (16.7%). The majority of HAdV infected patients were totally recovered (96.9%, 480/495); However, four (0.8%) patients, who were previously healthy and at the age of 2 years or younger died of pneumonia. Seasonal peaks of HAdV infection occurred in the summer season of 2012 and 2013; the predominant HAdV type was HAdV-3 (70%), followed by HAdV-7 (28%). These epidemiological features were different from those in Northern China. The HAdV-55 was identified and reported for the first time in Guangzhou metropolitan area. Phylogenetic analysis indicated that all the HVR sequences of the hexon gene of HAdV-3 and -7 strains have high similarity within their individual types, and these strains were also similar to those circulating in China currently, indicating the conservation of hexon genes of both HAdV-3 and HAdV-7. Conclusions Knowledge of the epidemiological features and molecular types of HAdV, a major pathogen of pediatric ARI, as well as other co-infected respiratory pathogens circulating in Guangzhou, southern China, is vital to predict and prevent future disease outbreaks in children. This study will certainly facilitate HAdV vaccine development and treatment of HAdV infections in children.

Polyethylenimine-functionalized silver nanoparticle-based co-delivery of paclitaxel to induce HepG2 cell apoptosis.

Hepatocarcinoma is the third leading cause of cancer-related deaths around the world. Recently, a novel emerging nanosystem as anticancer therapeutic agents with intrinsic therapeutic properties has been widely used in various medical applications. In this study, surface decoration of functionalized silver nanoparticles (AgNPs) by polyethylenimine (PEI) and paclitaxel (PTX) was synthesized. The purpose of this study was to evaluate the effect of Ag@ PEI@PTX on cytotoxic and anticancer mechanism on HepG2 cells. The transmission electron microscope image and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that Ag@PEI@PTX had satisfactory size distribution and high stability and selectivity between cancer and normal cells. Ag@PEI@PTX-induced HepG2 cell apoptosis was confirmed by accumulation of the sub-G1 cells population, translocation of phosphatidylserine, depletion of mitochondrial membrane potential, DNA fragmentation, caspase-3 activation, and poly(ADP-ribose) polymerase cleavage. Furthermore, Ag@PEI@PTX enhanced cytotoxic effects on HepG2 cells and triggered intracellular reactive oxygen species; the signaling pathways of AKT, p53, and MAPK were activated to advance cell apoptosis. In conclusion, the results reveal that Ag@ PEI@PTX may provide useful information on Ag@PEI@PTX-induced HepG2 cell apoptosis and as appropriate candidate for chemotherapy of cancer.

Silver Nanoparticle Based Codelivery of Oseltamivir to Inhibit the Activity of the H1N1 Influenza Virus through ROS-Mediated Signaling Pathways

As the therapeutic agent for antiviral applications, the clinical use of oseltamivir is limited with the appearance of drug-resistant viruses. It is important to explore novel anti-influenza drugs. The antiviral activity of silver nanoparticles (AgNPs) has attracted increasing attention in recent years and was a possibility to be employed as a biomedical intervention. Herein, we describe the synthesis of surface decoration of AgNPs by using oseltamivir (OTV) with antiviral properties and inhibition of drug resistance. Compared to silver and oseltamivir, oseltamivir-modified AgNPs (Ag@OTV) have remarkable inhibition against H1N1 infection, and less toxicity was found for MDCK cells by controlled-potential electrolysis (CPE), MTT, and transmission electron microscopy (TEM). Furthermore, Ag@OTV inhibited the activity of neuraminidase (NA) and hemagglutinin (HA) and then prevented the attachment of the H1N1 influenza virus to host cells. The investigations of the mechanism revealed that Ag@OTV could block H1N1 from infecting MDCK cells and prevent DNA fragmentation, chromatin condensation, and the activity of caspase-3. Ag@OTV remarkably inhibited the accumulation of reactive oxygen species (ROS) by the H1N1 virus and activation of AKT and p53 phosphorylation. Silver nanoparticle based codelivery of oseltamivir inhibits the activity of the H1N1 influenza virus through ROS-mediated signaling pathways. These findings demonstrate that Ag@OTV is a novel promising efficient virucide for H1N1.

The inhibition of H1N1 influenza virus-induced apoptosis by silver nanoparticles functionalized with zanamivir

As one of the most effective drugs for influenza virus infection, clinical application of zanamivir is restricted with the emergence of resistant influenza virus. It is crucial to manufacture novel pharmaceuticals against influenza virus infection. In recent years silver nanoparticles (AgNPs) have attracted wide attention in the antiviral field. In this study, we demonstrated surface decoration of AgNPs using zanamivir (ZNV) with antiviral properties. AgNPs co-delivery of the zanamivir nanosystem was designed to reverse influenza virus resistance. In brief, zanamivir modified AgNPs (Ag@ZNV) inhibited the neuraminidase activity of the H1N1 virus. Moreover, cytopathic effect showed that Ag@ZNV remarkably resisted H1N1 virus-induced apoptosis of MDCK cells, involving DNA fragmentation, chromatin condensation and caspase-3 activation. Ag@ZNV effectively reduced the accumulation of reactive oxygen species (ROS) induced by H1N1 virus and activation of both p38 and p53 signaling pathways. Taken together, our study indicates that Ag@ZNV is a novel promising pharmaceutical against H1N1 influenza virus infection.

Reversal of H1N1 influenza virus-induced apoptosis by silver nanoparticles functionalized with amantadine

Amantadine is an antiviral agent, but its clinical use against influenza viruses is limited because of the emergence of drug-resistant viruses. Thus, there is a need for novel anti-influenza agents. The antiviral activity of silver nanoparticles (AgNPs) has attracted increasing attention, with such nanoparticles being employed in biomedical interventions in recent years. Herein, we describe a simple method for surface decoration of AgNPs using amantadine. Co-delivery of AgNPs and amantadine was designed to overcome drug resistance. Compared with AgNPs and AM, amantadine-modified AgNPs (Ag@AM) were shown to inhibit H1N1 infection by CPE, MTT and TEM. Ag@AM also inhibited the activity of hemagglutinin (HA) and neuraminidase (NA). Mechanism investigations revealed that Ag@AM can block H1N1 from infecting host cells and prevent DNA fragmentation, chromatin condensation and activity of caspase-3. Ag@AM inhibited accumulation of reactive oxygen species (ROS) and reversed virus-induced apoptosis by H1N1 virus. Taken together, these findings suggest that Ag@AM is a novel promising efficient virucide for H1N1.

Delivery of VP1 siRNA to inhibit the EV71 virus using functionalized silver nanoparticles through ROS-mediated signaling pathways

Enterovirus 71 (EV71) is the primary causative agent of hand, foot, and mouth disease (HFMD). There is no effective drug therapy for EV71 at present. Small interfering RNA (siRNA), as a new therapeutic modality, provides a promising antiviral treatment, but it is unable to cross cell membranes. To overcome this limitation, nanotechnology has been proposed to mediate siRNA transfection. The antiviral activity of silver nanoparticles (AgNPs) has attracted increasing attention in recent years and can be employed in biomedical interventions. In this study, a simple method to prepare surface decorated AgNPs using polyethylenimine (PEI) and antiviral siRNA has been demonstrated. The development of AgNPs and PEI co-delivery of siRNA was designed to be antiviral. MTT assays and TEM images showed that PEI and siRNA-modified AgNPs (Ag@PEI@siRNA) have remarkable inhibition against EV71 infection and less toxicity to Vero cells. The mechanistic investigations revealed that Ag@PEI@siRNA could block EV71 from infecting host cells and prevent DNA fragmentation, chromatin condensation and activation of caspase-3. Ag@PEI@siRNA effectively inhibited the accumulation of reactive oxygen species (ROS) by the EV71 virus and activation of AKT and p53. Taken together, this study demonstrates that Ag@PEI@siRNA is a novel promising efficient virucide for EV71.

Inhibitory activity of selenium nanoparticles functionalized with oseltamivir on H1N1 influenza virus

As an effective antiviral agent, the clinical application of oseltamivir (OTV) is limited by the appearance of drug-resistant viruses. Due to their low toxicity and excellent activity, the antiviral capabilities of selenium nanoparticles (SeNPs) has attracted increasing attention in recent years. To overcome the limitation of drug resistance, the use of modified NPs with biologics to explore novel anti-influenza drugs is developing rapidly. In this study, OTV surface-modified SeNPs with superior antiviral properties and restriction on drug resistance were synthesized. OTV decoration of SeNPs (Se@OTV) obviously inhibited H1N1 infection and had less toxicity. Se@OTV interfered with the H1N1 influenza virus to host cells through inhibiting the activity of hemagglutinin and neuraminidase. The mechanism was that Se@OTV was able to prevent H1N1 from infecting MDCK cells and block chromatin condensation and DNA fragmentation. Furthermore, Se@OTV inhibited the generation of reactive oxygen species and activation of p53 phosphorylation and Akt. These results demonstrate that Se@OTV is a promising efficient antiviral pharmaceutical for H1N1.

Surface decoration of selenium nanoparticles with curcumin induced HepG2 cell apoptosis through ROS mediated p53 and AKT signaling pathways

Hepatocellular carcinoma (HCC) is one of the most lethal cancers, and the morbidity and mortality are increasing continuously. Curcumin plays an important role in anticancer activity, while its clinical application is limited by its poor aqueous solubility. To develop an aqueous formulation and improve the anticancer activity of curcumin, curcumin-surface decorated selenium nanoparticles (Se@Cur) were designed in the present study. Transmission electron microscopy (TEM) images and MTT assays indicated Se@Cur dramatically suppressed the proliferation of HepG2 cells and showed low toxicity to normal cells. Compared with SeNPs and curcumin, Se@Cur significantly inhibited the migration ability of HepG2 cells. Moreover, induction of apoptosis in HepG2 cells by Se@Cur was proved by accumulation of the sub-G1 cell population, nuclear condensation and activation of caspase-3. Furthermore, Se@Cur promoted intracellular ROS overproduction and induced apoptosis via activating p53 and AKT signal pathways. Finally, in a xenograft nude mice model, Se@Cur suppressed the growth of tumors. Altogether, the findings in the present study demonstrated the application of Se@Cur as a safe and hopeful strategy for chemotherapeutics of HCC.

Targeted delivery of siRNA using RGDfC-conjugated functionalized selenium nanoparticles for anticancer therapy

Lack of biocompatible and effective delivery carriers is a significant shortcoming for siRNA-mediated cancer therapy. To overcome these limitations, selenium nanoparticles (SeNPs) have been proposed for siRNA transfection vehicles. In this study, we synthesized novel RGDfC peptide modified selenium nanoparticles (RGDfC-SeNPs) as a gene vehicle, which was expected to improve the tumor-targeted delivery activity. RGDfC-SeNPs were compacted with siRNAs (anti-Oct4) by electrostatic interaction, which was capable of protecting siRNA from degradation. RGDfC-SeNPs exhibited excellent ability to deliver siRNA into HepG2 cells. siRNA transfection assay showed that RGDfC-SeNPs presented a higher gene silencing efficacy than conventional lipofectamine 2000. The cytotoxicity of RGDfC-SeNPs/siRNA on normal cells was lower than that on tumor cells, indicating that RGDfC-SeNPs/siRNA exhibited selectivity between normal and cancer cells. Additionally, Oct4 knockdown mediated by the selenium nanoparticle transfection arrested HepG2 cells mainly at the G2/M phase and significantly induced HepG2 cell apoptosis. Western blotting results showed that RGDfC-SeNPs/siRNA might trigger Wnt/β-catenin signaling, and further activate a BCL-2 apoptosis-related signaling pathway to advance HepG2 cell apoptosis. In vivo biodistribution experiments indicated that RGDfC-SeNPs/siRNA nanoparticles were specifically targeted to the HepG2 tumors. Most importantly, RGDfC-SeNPs/siRNA inhibited tumor growth significantly and induced HepG2 cell apoptosis via silencing the Oct4 gene. In addition, the results of H&E staining demonstrated that RGDfC-SeNPs/siRNA had negligible toxicity on the major organs of mice. In a word, this study provides a novel strategy for the design of biocompatible and effective siRNA delivery vehicles in cancer therapy.