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Recently, hollow structures have attracted much attention due to their high specific surface area, clear interior space, low density and good permeability. Among them, manganese dioxide (MnO2) hollow structure has also been widely studied for catalysis, drug delivery and energy storage. Based on the characteristics of low pH and high GSH concentration in tumor microenvironment, it is possible to develop an intelligent drug delivery system with pH/GSH response based on hollow mesoporous MnO2 nanospheres. In addition, the excellent physical and chemical properties of MnO2 nanomaterials provide conditions for its synergistic photothermal therapy. For example, Mn2+ released after manganese dioxide reacts with GSH can enhance T1-MAGNETIC resonance (MR) imaging. Meanwhile, manganese dioxide can also react with H2O2 in tumor microenvironment to release oxygen and alleviate tumor hypoxia. In order to prevent drug loss during delivery, a GSH-responsive hollow mesoporous manganese dioxide microsphere was selected as the drug carrier in this paper, and a series of studies were carried out on the performance of the carrier. Hollow mesoporous MnO2 nanospheres with particle size below 100 nm were prepared by hydrothermal method, and their response to tumor microenvironment was simulated in vitro. It has been proved that hollow mesoporous MnO2 nanospheres can be desorbed at low pH and GSH response, and can be used to deliver drugs or photothermal agents, as well as for collaborative cancer imaging and treatment. [ABSTRACT FROM AUTHOR]

Aim: To construct recombinant clostridium sporogenes modified with the extracellular domain of human oncogene HER2/neu, to lay a foundation for further study of its antitumor effect., Methods: The extracellular domain (ECD) of HER2/neu gene was attached to the downstream of promoter and signal sequence of clostridia endo-1, 4-glucanase (eglAp) by SOE-PCR to construct fusion gene eglAp-HER2/neu, which was then inserted into E.coli-clostridia shuttle plasmid pIMP1 to construct recombinant plasmid pIMP1-eHER2/neu. The recombinant plasmid was firstly transformed into E.coli DH5α.Then the correct construct was identified and introduced into C. sporogenes by electroporation. Positive clones were selected by erythromycin resistance, bacteria PCR were used for verification., Results: Restriction map and sequencing result showed that the sequence and ORF of fusion gene eglAp-HER2/neu in recombinant plasmid pIMP1-eHER2/neu was correct. Bacteria PCR results indicated that the recombinant plasmid pIMP1-eHER2/neu was successfully transformed into C.sporogenes. After more than 20 passages under antibiotic pressure, C.sporogenes transformants could stably carry the recombinant plasmid pIMP1-eHER2/neu., Conclusion: Stable C.sporogenes transformants with the recombinant plasmid pIMP1-eHER2/neu are successfully acquired, which laid a foundation for further anti-tumor study.

Aim: To construct recombinant vectors expressing siRNA that target CD59 gene and a stable-inhibit cell line A2780 in order to analyze the role of CD59 in the protection to complement-mediated cytolysis., Methods: The 60 bp encoded targeting CD59 gene shRNA sequence was cloned into pSUPER vector with DNA recombinant technique. The ovary cancer cell A2780 was transfected with this recombinant plasmid using liposome and the stable strains was selected by using G418-medium, CD59 mRNA and protein level was detected by RT-PCR and Western blot, and its function was analysed by dye release assay., Results: The pSUPER-siRNA expressing vector was successfully constructed. And a stable cell line A2780 was selected and was detected the expression of GFP. The siRNA vector effectively inhibited the CD59 gene expression from mRNA and protein level. Dye release assay suggested that CD59's protection to complement-mediated cytolysis decreased., Conclusion: The siRNA vector targeting CD59 gene could consistently inhibit CD59 expression. Furthermore, it decreased CD59's protection against complement. These results may pave the way for studying the role of CD59 in the immune escape of tumors cells as well as in tumor therapy.