title: Gene transfer of vasostatin, a calreticulin fragment, into neuroendocrine tumor cells results in enhanced malignant behavior.
abstract: Vasostatin, a fragment of calreticulin, was transfected in the BON cell line to evaluate the feasibility of using it for gene therapy in neuroendocrine tumors. Vasostatin transfected cells were subcutaneously inoculated in nude mice. Burkitt lymphoma cell line, CA46, colorectal adenocarcinoma cell line, SW480, as well as endothelial cells PAE and SVEC4 were used for evaluating the function of vasostatin. The results demonstrated that vasostatin transfer caused enhanced malignant behavior of neuroendocrine tumor cell line, BON. Cell adhesion, spreading and cellular invasion were also enhanced in vasostatin-expressing BON cells. Tumor suppressor genes including p53, nm23, Rb and vinculin were down-regulated. Moreover, cell cycle regulatory protein, p27kip1, and cell differentiation-related protein kinase, PKR, were also significantly down-regulated. Furthermore, expression of NKG2D ligands, MICA and MICB, were down-regulated. Mice implanted with vasostatin-expressing BON cells showed an earlier and faster tumor growth compared to wild type. Anti-proliferative effects of vasostatin could not be proven in other cells except in PAE. These results indicated that vasostatin does probably not have a tumor growth inhibitory effect by itself, but rather modulates processes which are necessary for tumor growth. Therefore, one should be very careful when using vasostatin as an anti-tumoral agent in clinical trials, at least for neuroendocrine tumors.
authors.affiliation: Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Minghui
authors.initials: M
authors.lastname: Liu
authors.forename: Hassan
authors.initials: H
authors.lastname: Imam
authors.forename: Kjell
authors.initials: K
authors.lastname: Oberg
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D020533:Angiogenesis Inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D037282:Calreticulin / Q000235:genetics / Q000378:metabolism*; D002276:Carcinoid Tumor / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D016147:Genes, Tumor Suppressor / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D018358:Neuroendocrine Tumors / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D013552:Swine
chemical_list: D020533:Angiogenesis Inhibitors; D037282:Calreticulin; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D012333:RNA, Messenger; C121986:vasostatin