Abstract
Cyclin D1 plays an important role in regulating the progression of cells through the G1 phase of the cell cycle. This gene is frequently overexpressed in human colon cancer. To address the role of cyclin D1 in growth control and tumorigenesis in this disease, we have overexpressed an antisense cyclin D1 cDNA construct in the human colon cancer cell line SW480E8, which expresses high levels of cyclin D1. The integration and expression of the antisense construct was verified by Southern and Northern blot analyses, respectively, and resulted in decreased expression of the cyclin D1 protein. This was associated with decreased levels of the Rb and p27Kip1 proteins. In addition, the hypophosphorylated form of Rb was increased in these cells. The SW480E8 antisense cyclin D1 cells displayed an increased doubling time, a decrease in saturation density, decreased plating efficiency and anchorage-independent growth, and a loss of tumorigenicity in nude mice. These findings provide direct evidence that increased expression of cyclin D1 in colon tumor cells contributes to their abnormal growth and tumorigenicity. The ability to revert the transformed phenotype of these cells with antisense cyclin D1 suggests that cyclin D1 or its associated cyclin-dependent kinase 4 may be useful targets in the therapy of colon cancer.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Biomarkers, Tumor / metabolism*
-
Cell Cycle
-
Cell Cycle Proteins*
-
Cell Division / drug effects
-
Colonic Neoplasms / genetics
-
Colonic Neoplasms / metabolism*
-
Colonic Neoplasms / pathology
-
Cyclin D1
-
Cyclin-Dependent Kinase 4
-
Cyclin-Dependent Kinase 6
-
Cyclin-Dependent Kinase Inhibitor p27
-
Cyclin-Dependent Kinases / metabolism
-
Cyclins / genetics
-
Cyclins / metabolism*
-
Cyclins / physiology
-
DNA, Antisense / metabolism*
-
Down-Regulation
-
Genetic Vectors
-
Humans
-
Mice
-
Mice, Nude
-
Microtubule-Associated Proteins / metabolism
-
Neoplasm Proteins / metabolism*
-
Oncogene Proteins / genetics
-
Oncogene Proteins / metabolism*
-
Oncogene Proteins / physiology
-
Protein Serine-Threonine Kinases / metabolism
-
Proto-Oncogene Proteins*
-
Retinoblastoma Protein / metabolism
-
Tumor Cells, Cultured
-
Tumor Suppressor Proteins*
Substances
-
Biomarkers, Tumor
-
Cdkn1b protein, mouse
-
Cell Cycle Proteins
-
Cyclins
-
DNA, Antisense
-
Microtubule-Associated Proteins
-
Neoplasm Proteins
-
Oncogene Proteins
-
Proto-Oncogene Proteins
-
Retinoblastoma Protein
-
Tumor Suppressor Proteins
-
Cyclin D1
-
Cyclin-Dependent Kinase Inhibitor p27
-
Protein Serine-Threonine Kinases
-
CDK4 protein, human
-
CDK6 protein, human
-
Cdk4 protein, mouse
-
Cdk6 protein, mouse
-
Cyclin-Dependent Kinase 4
-
Cyclin-Dependent Kinase 6
-
Cyclin-Dependent Kinases