title: Induction of tumorigenesis and metastasis by the murine orthologue of tumor protein D52.
abstract: Expression studies have consistently identified tumor protein D52 (TPD52) overexpression in tumor cells. Murine TPD52 (mD52) shares 86% identity with the human orthologue. To study a possible role for TPD52 in transformation, 3T3 fibroblasts were transfected with the full-length cDNA for mD52. Expression of mD52 was confirmed by reverse transcription-PCR (RT-PCR), real-time PCR, and Western blot analysis compared with 3T3 and vector-transfected 3T3 (3T3.V), and the resultant cell line was designated 3T3.mD52. At 4 weeks, 3T3.mD52 gained a 2-fold increase in growth rate, lost contact inhibition, and exhibited a marked phenotype change. Further characterization revealed an acquired ability for anchorage-independent cell growth. To determine whether 3T3.mD52 had become tumorigenic, naïve, healthy, immunocompetent syngeneic mice were inoculated subcutaneously with varying cell doses. Tumors measuring >1 cm(2) were detected 60 days postinoculation with 3T3.mD52, and a 50% subcutaneous tumor incidence was obtained with as few as 5 x 10(5) 3T3.mD52 cells. Remarkably, when lungs from 3T3.mD52 tumor-bearing mice were analyzed, numerous tumor nodules were observed, ranging from nodules less than 10 to nodules too numerous to count (inoculation with 1 x 10(5) and 5 x 10(6) cells, respectively). Further support for the metastatic capacity of 3T3.mD52 was the demonstration that transforming growth factor (TGF)-betaR1 (receptor) expression decreased and TGF-beta1 secretion increased in 3T3.mD52 compared with 3T3 controls. cDNA microarray analysis showed a gene expression pattern that further supported mD52-induced transformation and metastasis. Together, these data suggest that mD52 expression in 3T3 cells initiated cellular transformation, tumorigenesis, and progression to metastasis.
authors.affiliation: Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, 3601 4th Street, MS 6591, Lubbock, TX 79430, USA.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Lewis
authors.forename: Laura A
authors.initials: LA
authors.lastname: Payton
authors.forename: Jill G
authors.initials: JG
authors.lastname: Whitford
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Byrne
authors.forename: David I
authors.initials: DI
authors.lastname: Smith
authors.forename: Libang
authors.initials: L
authors.lastname: Yang
authors.forename: Robert K
authors.initials: RK
authors.lastname: Bright
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D005260:Female; D008175:Lung Neoplasms / Q000556:secondary*; D051379:Mice; D008807:Mice, Inbred BALB C; D041681:NIH 3T3 Cells; D009363:Neoplasm Proteins / Q000378:metabolism*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D009363:Neoplasm Proteins; C486415:Tpd52 protein, mouse; D053773:Transforming Growth Factor beta1