title: Expression of adenovirus type 5 E1A in the methylotrophic yeast Pachia pastoris and the inhibitory effect on S-180 tumor growth.
abstract: The human adenovirus type 5 (Ad5) early-region 1A (E1A) proteins have been shown to have strong tumor-suppressive activities in human tumor cells and to enhance the sensitivity of a variety of malignant tumors to apoptosis induced by ionizing radiation and chemotherapeutic agents. However, the inherent limitations of E1A gene therapy prevent its application, such as the efficiency of expression, precision of targeting, and toxicity of vector. This prompted us to construct an E1A expression vector (pPIC9/E1A) and express the E1A protein in the methylotrophic yeast Pichia pastoris. The E1A protein was purified using two steps of ion-exchange column chromatography on HiTrap Q and HiTrap SP. The analysis indicated that the E1A protein/liposome inhibited S-180 tumor growth and also rendered the S-180 tumor strongly susceptible to the anticancer drug bleomycin in vivo. Furthermore, tunnel assay clearly revealed that the mechanism was induction of cellular apoptosis. Importantly, the E1A protein overcame the limitations of gene therapy. Thus the E1A protein may be a useful therapeutic agent for some malignant tumors.
authors.affiliation: Cancer Institute, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100021, China.
authors.forename: Yewei
authors.initials: Y
authors.lastname: Ma
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Zhou
authors.forename: Qingzheng
authors.initials: Q
authors.lastname: Zhao
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Li
authors.forename: Yuying
authors.initials: Y
authors.lastname: Liu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Yangpei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017500:Adenovirus E1A Proteins / Q000008:administration & dosage* / Q000096:biosynthesis; D000818:Animals; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D005822:Genetic Vectors / Q000008:administration & dosage; D006131:Growth Inhibitors / Q000008:administration & dosage* / Q000096:biosynthesis; D006801:Humans; D051379:Mice; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays / Q000379:methods*; D015003:Yeasts / Q000378:metabolism*
chemical_list: D017500:Adenovirus E1A Proteins; D006131:Growth Inhibitors