title: Induction of chromosomal instability in colonic cells by the human polyomavirus JC virus.
abstract: Most colorectal cancers display chromosomal instability, which is characterized by gross chromosomal rearrangements, loss of heterozygosity and aneuploidy. We have previously demonstrated a link between JC virus strains Mad-1 and Delta98 and colorectal cancer. Others have also associated the virus to the induction of colon cancer and aneuploid brain tumors by producing a highly tumorigenic protein named T antigen (TAg), which binds to beta-catenin and inactivates key proteins such as p53. The aim is to demonstrate that JC virus is capable of inducing chromosomal instability in colonic cells. We used the human colon cancer cell line RKO as a model. The cell line has wild-type p53, wild-type beta-catenin and APC and is diploid. Neuroblastoma JCI cells, which are infected with the virus, VA13 fibroblasts, which are transformed by the SV40 TAg, were used as positive controls. HCT116, which has mutated beta-catenin, and SW480, which is a model of CIN, were also used as controls. The genomes of the Mad-1 and Delta98 strains were transfected into cells. As negative controls we used pUC or no plasmids. Cells were collected at 0, 7, 14, and 21 days after transfection. PCR was used for the detection of TAg and the regulatory region DNA sequences at different time frames and Southern blot of whole genomic extracts for viral DNA integration into the host genome. Immunofluorescence and Western blot were performed for TAg, viral capsid proteins, and nuclear beta-catenin expressions, whereas coimmunoprecipitation was used to detect protein interactions. Karyotype analysis and electron microscopy were performed to seek chromosomal instability and cell abnormalities, respectively. Retention of viral sequences was observed for Mad-1- and Delta98-transfected RKO cells at all time frames with PCR only, whereas Southern blot analysis showed nonintegrated sequences at T7 alone. TAg and capsid protein expressions, as well as increased p53 and nuclear beta-catenin, were observed between T0 and T7 for Mad-1 and Delta98 alone. Also, interaction between TAg and both p53 and beta-catenin was also observed between T0 and T7. Chromosomal instability, characterized by chromosomal breakage, dicentric chromosomes, and increasing ploidy, was observed at all time frames for Mad-1 and Delta98, as well as cell abnormalities. In conclusion, we demonstrate that JC virus Mad-1 and Delta98 are able to induce chromosomal instability in colonic cells with a hit and run mechanism that involves an early interaction with beta-catenin and p53.
authors: Department of Internal Medicine and Gastroenterology, University of Bologna, Via Massarenti 9, Pad 5 Stanza 28, 40138 Bologna, Italy. ricciard@med.unibo.it
authors: Luigi
authors: L
authors: Ricciardiello
authors: Michele
authors: M
authors: Baglioni
authors: Catia
authors: C
authors: Giovannini
authors: Milena
authors: M
authors: Pariali
authors: Giovanna
authors: G
authors: Cenacchi
authors: Alessandro
authors: A
authors: Ripalti
authors: Maria Paola
authors: MP
authors: Landini
authors: Hirofumi
authors: H
authors: Sawa
authors: Kazuo
authors: K
authors: Nagashima
authors: Richard J
authors: RJ
authors: Frisque
authors: Ajay
authors: A
authors: Goel
authors: C Richard
authors: CR
authors: Boland
authors: Mauro
authors: M
authors: Tognon
authors: Enrico
authors: E
authors: Roda
authors: Franco
authors: F
authors: Bazzoli
mesh_terms: D000957:Antigens, Viral, Tumor / Q000096:biosynthesis / Q000378:metabolism; D045744:Cell Line, Tumor; D002472:Cell Transformation, Viral / Q000235:genetics*; D043171:Chromosomal Instability; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000378:metabolism; D016679:Genome, Viral; D006801:Humans; D007577:JC Virus / Q000235:genetics*; D011230:Precancerous Conditions / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D015534:Trans-Activators / Q000096:biosynthesis / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051176:beta Catenin
chemical_list: D000957:Antigens, Viral, Tumor; C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; D051176:beta Catenin