ABSTRACT
CT120, a novel membrane-associated gene implicated in lung carcinogenesis, was previously identified from chromosome 17p13.3 locus, a hot mutation spot involved in human malignancies. In the present study, we further determined that CT120 ectopic expression could promote cell proliferation activity of NIH3T3 cells using MTS assay, and monitored the downstream effects of CT120 in NIH3T3 cells with Atlas mouse cDNA expression arrays. Among 588 known genes, 133 genes were found to be upregulated or downregulated by CT120. Two major signaling pathways involved in cell proliferation, cell survival and anti-apoptosis were overexpressed and activated in response to CT120: One is the Raf/MEK/Erk signal cascades and the other is the PI3K/Akt signal cascades, suggesting that CT120 might contribute, at least in part, to the constitutively activation of Erk and Akt in human lung cancer cells. In addition, some tumor metastasis associated genes cathepsin B, cathepsin D, cathepsin L, MMP-2/TIMP-2 were also upregulated by CT120, upon which CT120 might be involved in tumor invasiveness and metastasis. In addition, CT120 might play an important role in tumor progression through modulating the expression of some candidate "Lung Tumor Progression" genes including B-Raf, Rab-2, BAX, BAG-1, YB-1, and Cdc42.
Subject(s)
Gene Expression Profiling , Lung Neoplasms/genetics , Membrane Proteins/genetics , Animals , Cell Proliferation , Genetic Vectors/genetics , Humans , Membrane Proteins/metabolism , Mice , NIH 3T3 Cells , Neoplasm Proteins , Promoter Regions, Genetic/genetics , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/geneticsABSTRACT
We have identified IC53-2, a human homologue of the rat C53 gene from a human placenta cDNA library (GeneBank Accession No.AF217982). IC53-2 can bind to the CDK5 activator p35 by in vitro association assay. IC53-2 is mapped to human chromosome 17q21.31. The IC53-2 transcript is highly expressed in kidney, liver, skeletal muscle and placenta. It is abundantly expressed in SMMC-7721, C-33A, 3AO, A431 and MCF-7 cancer cell lines by RT-PCR assay. Stable transfection of IC53-2 cDNA into the hepatocellular carcinoma SMMC-7721 cell remarkably stimulates its growth in vitro. The above results indicate that IC53-2 is a novel human gene, which may be involved in the regulation of cell proliferation.
Subject(s)
Carcinoma, Hepatocellular/genetics , Carrier Proteins/isolation & purification , Cell Division/genetics , Cell Transformation, Neoplastic/genetics , Cyclin-Dependent Kinases/genetics , Intracellular Signaling Peptides and Proteins , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/isolation & purification , Carcinoma, Hepatocellular/metabolism , Carrier Proteins/genetics , Cell Cycle Proteins , Cell Transformation, Neoplastic/metabolism , Chromosomes, Human, Pair 17 , Cloning, Molecular , Cyclin-Dependent Kinase 5 , Gene Expression Regulation, Neoplastic/genetics , HeLa Cells , Humans , Molecular Sequence Data , Protein Binding/genetics , Protein Isoforms/genetics , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Transfection , Tumor Suppressor ProteinsABSTRACT
BACKGROUND & OBJECTIVE: A novel membrane-associated gene CT120 was isolated from chromosome 17p13.3 locus in our laboratory. Its mRNA was not expressed in human normal lung tissues, but was abundant in human lung cancer cell line SPC-A-1. This study was designed to investigate the differential expression patterns of CT120 in different lung cancer and noncancerous tissues using immunohistochemistry and to explore the effects of ectopic expression and overexpression of CT120 on cell growth in vitro and in vivo. METHODS: A polypeptide at the C-terminus of CT120 was selected by bioinformatics, then was synthesized and conjugated to KLH (a high molecular carrier). The chicken anti-CT120 antibody IgY was prepared with the synthesized antigen and was used to determine the different expression patterns of CT120 in various tumor cell lines and in lung cancer and noncancerous tissues. The effects of ectopic expression of CT120 on NIH/3T3 cell growth were investigated through colony formation analysis. The effect of overexpression of CT120 on the cell growth of A549 was analyzed using growth curve assay and tumor formation assay of transfected cells in nude mice. RESULTS: The novel gene CT120 expressed in various tumor cell lines and expressed remarkably higher in lung cancers than in noncancerous tissues as well as normal lung tissues. Also, it promoted the proliferation of NIH/3T3 and A549 cells in vitro and in vivo. CONCLUSION: CT120 gene may be a novel candidate gene closely related to lung carcinogenesis.
