title: Protein tyrosine phosphatase PRL-3 in malignant cells and endothelial cells: expression and function.
abstract: Protein tyrosine phosphatase PRL-3 mRNA was found highly expressed in colon cancer endothelium and metastases. We sought to associate a function with PRL-3 expression in both endothelial cells and malignant cells using in vitro models. PRL-3 mRNA levels were determined in several normal human endothelial cells exposed or unexposed to the phorbol ester phorbol 12-myristate 13-acetate (PMA) and in 27 human tumor cell lines. In endothelial cells, PRL-3 mRNA expression was increased in human umbilical vascular endothelial cells and human microvascular endothelial cells (HMVEC) exposed to PMA. An oligonucleotide microarray analysis revealed that PRL-3 was among the 10 genes with the largest increase in expression on PMA stimulation. Phenotypically, PMA-treated HMVEC showed increased invasion, tube formation, and growth factor-stimulated proliferation. A flow cytometric analysis of cell surface markers showed that PMA-treated HMVEC retained endothelial characteristics. Infection of HMVEC with an adenovirus expressing PRL-3 resulted in increased tube formation. In tumor cells, PRL-3 mRNA levels varied markedly with high expression in SKNAS neuroblastoma, MCF-7 and BT474 breast carcinoma, Hep3B hepatocellular carcinoma, and HCT116 colon carcinoma. Western blotting analysis of a subset of cell line lysates showed a positive correlation between PRL-3 mRNA and protein levels. PRL-3 was stably transfected into DLD-1 colon cancer cells. PRL-3-overexpressing DLD-1 subclones were assessed for doubling time and invasion. Although doubling time was similar among parental, empty vector, and PRL-3 subclones, invasion was increased in PRL-3-expressing subclones. In models of endogenous expression, we observed that the MCF-7 cell line, which expresses high levels of PRL-3, was more invasive than the SKBR3 cell line, which expresses low levels of PRL-3. However, the MDA-MB-231 cell line was highly invasive with low levels of PRL-3, suggesting that in some models invasion is PRL-3 independent. Transfection of a PRL-3 small interfering RNA into MCF-7 cells inhibited PRL-3 expression and cell invasion. These results indicate that PRL-3 is functional in both endothelial cells and malignant cells and further validate PRL-3 as a potentially important molecular target for anticancer therapy.
authors.affiliation: Genzyme Corp., 1 Mountain Road, Framingham, MA 01701, USA.
authors.forename: Cecile
authors.initials: C
authors.lastname: Rouleau
authors.forename: Andre
authors.initials: A
authors.lastname: Roy
authors.forename: Thia
authors.initials: T
authors.lastname: St Martin
authors.forename: Michael R
authors.initials: MR
authors.lastname: Dufault
authors.forename: Paula
authors.initials: P
authors.lastname: Boutin
authors.forename: Dapei
authors.initials: D
authors.lastname: Liu
authors.forename: Mindy
authors.initials: M
authors.lastname: Zhang
authors.forename: Kristin
authors.initials: K
authors.lastname: Puorro-Radzwill
authors.forename: Lori
authors.initials: L
authors.lastname: Rulli
authors.forename: Dave
authors.initials: D
authors.lastname: Reczek
authors.forename: Rebecca
authors.initials: R
authors.lastname: Bagley
authors.forename: Ann
authors.initials: A
authors.lastname: Byrne
authors.forename: William
authors.initials: W
authors.lastname: Weber
authors.forename: Bruce
authors.initials: B
authors.lastname: Roberts
authors.forename: Katherine
authors.initials: K
authors.lastname: Klinger
authors.forename: William
authors.initials: W
authors.lastname: Brondyk
authors.forename: Mariana
authors.initials: M
authors.lastname: Nacht
authors.forename: Steve
authors.initials: S
authors.lastname: Madden
authors.forename: Robert
authors.initials: R
authors.lastname: Burrier
authors.forename: Srinivas
authors.initials: S
authors.lastname: Shankara
authors.forename: Beverly A
authors.initials: BA
authors.lastname: Teicher
mesh_terms: D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology; D015870:Gene Expression / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic; D052138:Genes, Neoplasm / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000032:analysis / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; C408143:SMR3B protein, human; D012471:Salivary Proteins and Peptides; D013755:Tetradecanoylphorbol Acetate