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Expression of p16INK4a suppresses the unbounded and anchorage-independent growth of a glioblastoma cell line that lacks p16INK4a.

Authors
Type
Published Article
Journal
Biochemical and biophysical research communications
Publication Date
Volume
231
Issue
3
Pages
743–750
Identifiers
PMID: 9070885
Source
Medline
License
Unknown

Abstract

p16INK4a is a inhibitory protein of Cyclin-dependent kinase 4(Cdk4).p16 negatively regulates the cell cycle progression from G1 to S phase. Functional p16 is absent from many human cancers, as well as from many established lines of tumor cells. However, it is not clear whether expression of p16 in p16-deficient tumor cells can suppress their anchorage-independent growth. Therefore, we introduced a cDNA for p16INK4a into the human glioblastoma cell line T98G, which lacks a gene for p16INK4a. We isolated several clones that stably expressed various amounts of p16 protein. The doubling time of the various clones was generally prolonged. Clones with high-level expression of p16 protein had characteristics of restricted growth, such as contact inhibition, while the parental T98G cells had no such characteristics. Furthermore, the efficiency of colony formation in soft agar was dramatically decreased in the case of cells that expressed exogenous p16. Our observations suggest that the expression of p16 protein restricts the unbounded growth and the anchorage-independent growth of tumor cells.

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