Journal Article

Transformation of Madin-Darby canine kidney (MDCK) epithelial cells by Epstein-Barr virus latent membrane protein 1 (LMP1) induces expression of Ets1 and invasive growth

Harada, Shizuko, Hasegawa, Kazuki, Furukawa, Mitsuru, Horikawa, Toshiyuki, Yoshizaki, Tomokazu, Seiki, Motoharu, Sato, Hiroshi, Miyamori, Hisashi, Kim, Kwang-Rok

2000

Overview

The Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) has a significant role in initiating EBV-associated lymphoproliferative disease and EBV-related malignancies. In view of clinical features related to the type of EBV latency, LMP1 may influence invasiveness of EBV associated tumors categorized as types II and III as represented on nasopharyngeal carcinoma (NPC). To screen for genes associated with invasion of epithelial cells transformed by LMP1, Madin-Darby canine kidney (MDCK) epithelial cells were transformed by LMP1. Stable transfection of a LMP1 gene into MDCK cells induced morphological change from cobblestone to a long spindle-shape, reduced cell-cell adhesion and caused high cell motility. Parental MDCK cells, which form spherical cysts in three-dimensional collagen gel matrix, form branching tubules following exposure to hepatocyte growth factor (HGF). MDCK cells transformed by LMP1 showed invasive growth to form branching tubules into collagen gel without HGF-treatment. mRNA differential display and Northern hybridization identified plasminogen activator inhibitor-1 (PAI-1), urokinase type plasminogen activator (uPA) and ets1 as genes upregulated during transformation by LMP1. Expression of a dominant negative type of Etsl in LMP1-transformed cells downregulated uPA expression and cell motility. Deletion of LMP1 cytoplasmic carboxy-terminal activating region 1 (CTAR1) domain abolished transformation, but a deletion mutant lacking CTAR2 domain still retained transforming and uPA-inducing ability. Expression of Ets1 was immunolocalized in tumor cells of NPC tissue which frequently express LMP1. Taken together, it is suggested that LMP1 induces expression of Ets1 which may contribute to invasion of NPC by stimulating cell motility and uPA expression.

• Publisher: Nature Publishing,Nature Publishing Group
• Subject: Amino acids / Animals / Biological and medical sciences / Cell adhesion / Cell Line / Cell Movement / Cell physiology / Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes / Cell Transformation, Neoplastic / Cells / Clonal deletion / Collagen / Cysts / Deletion mutant / Differential display / Dogs / Epithelial cells / Epithelial Cells - cytology / Epithelial Cells - physiology / Epstein-Barr virus / Ets-1 protein / Ets1 protein / Fundamental and applied biological sciences. Psychology / Gene Expression / Genetic transformation / Growth factors / Hepatocyte growth factor / Herpesvirus 4, Human - physiology / Hybridization / Immunoproliferative diseases / Invasiveness / Kinases / Latency / Latent membrane protein 1 / LMP1 protein / Lymphocytes / Medical research / Membrane proteins / Molecular and cellular biology / Motility / mRNA / Nasopharyngeal carcinoma / Nasopharyngeal Neoplasms - metabolism / Nasopharyngeal Neoplasms - pathology / Neoplasm Invasiveness / Oncogene Proteins, Viral - biosynthesis / Oncogene Proteins, Viral - genetics / Plasminogen Activator Inhibitor 1 - genetics / Plasminogen activator inhibitors / Proteins / Proto-Oncogene Protein c-ets-1 / Proto-Oncogene Proteins - genetics / Proto-Oncogene Proteins - physiology / Proto-Oncogene Proteins c-ets / Throat cancer / Transcription Factors - genetics / Transcription Factors - physiology / Transfection / Transformed cells / Tubules / Tumor cells / Tumors / Urokinase-Type Plasminogen Activator - genetics / Viral Matrix Proteins - biosynthesis / Viral Matrix Proteins - genetics