ABSTRACT
Telomere maintenance plays a critical role in cancer progression.Approximately 85% human cancer cells maintain their telomere length through activation of telomerase.Other 15%of cancers maintain telomere length independently of telom-erase by alternative lengthening of telomeres (ALT)pathway. Both events are equally important for telomere length mainte-nance of cancer cells.Human telomere consists of a series of G rich DNA sequences,which could form G-quadruplex.The for-mation of this structure can block the extension of telomeres by telomerase or ALT,resulting in cancer cell death.Thereby,G-quadruplex has been one of the focuses of anticancer therapy in recent years.This review focuses on the latest progress of G-quadruplex stabilizers.
ABSTRACT
To investigate the therapeutical effect of the chitosan (CS) nana-paritclessingle administration of Bla g 7 polypeptide - CS nanoparticles used as a BLa g7 polypeptide antigen in the sensitized mice and to explore its immune mechanism, the polypeptide Bla g 7 was enclosed into CS to develop the Bla g 7 polypeptide entrapped CS nano-particles. In the present experiment, 25 BALB/c mice were divided randomly into the Bla g 7 polypeptide treated group(group A , n= 5) , Bla g 7 polypeptide plus CS treated group(group B , n= 5) , CS=control group (group C , n= 5),model group (group D , n= 5) and negative control group (group E, n= 5), After sensitization by intraperitoneal route and challenged by intranasal instillation with crude extracts of German cockroach , the inflammatory changes in the mouse lung tissues were observed after the lung tissues were fixed and stained with haematoxylin and eosin(H&E). The total cell number and the cellular composition of bronchoalveolar lavage fluid (BALF) were detected; and the changes of the mouse airway hyper-reactivity were determined by the whole body plethysmograohy pre-and post-treatments. In these ways, the Bla g7 peptide CS nano-particel vaccine was successfully developed. It was found that the pathological changes in mouse lungs in group D were not so prominent in comparison with those of group A of mice sensitized with crude extract of German cockroach. in which the development of eosinophil infiltration in the airway of mice in D group could be demonstrated. The lung inflammatory reactions and the mucus secretion in lungs of D group were significantly alleviated than those of the B group. but there was no therapeutical effect for the mice fed with the isodoses of Bla g 7 polypeptide or CS. It was also shown that the airway hyper-reactivity of mice was depressed after treatment (P<0.05). It is evident that CS nano-particles show definite therapeutical effect and may serve as a powerful vehicle to improve the tolerance effect of the Bla g 7 polypeptide-CS nanoparticle vaccine, and a single administration of Bla g 7 polypeptide-CS nanoparticle vaccine may hold promise as a new strategy to desensitize the Bla g 7 sensitized disease.
ABSTRACT
Objective To clone the gene of arginine kinase (AK) from Periplaneta americana, produce its recombinant protein and investigate its allergenicity. Method The cDNA of AK was cloned using specific primers from the total RNA of P. americana. The cloned gene was inserted into pMD18-T vector and digested by BamHI and HindⅢ. The cDNA was sequenced and subcloned into pET-28a expression vector. The cloned AK cDNA gene was expressed in Escherichia coli BL21 (DE3) by IPTG induction. The recombinant AK (rAK) was purified by metal (Ni2+) chelating affinity chromatography. Its allergenicity was examined by both Western blotting and enzyme-linked immunosorbent assay (ELISA). Result The cloned cDNA ORF sequence (Accession no. EU429466) contained 1 068 bp and encoded 365 amino acids. Its sequence homology with the published one (Accession no. AY563004) was 99.9% at nucleotide level. The allergen rAK was highly expressed in E. coli BL21 (DE3) as a soluble protein mainly with the molecular weight of about Mr 45 000 under induction of IPTG and purified by 6-His-tag purification system. Both in the non-denaturalization and denaturalization conditions, the recombinant allergen was identified as its affinity to IgE antibodies from the cockroach-allergic patient sera by Western blotting and ELISA. Conclusion The recombinant cockroach arginine kinase has been obtained with proper allergenicity.