Id1 delays senescence of primary human melanocytes.
The Id family of helix-loop-helix transcription factors is upregulated in a variety of human malignancies and has been implicated in promoting tumorigenesis through effects on cell growth, differentiation, and tumor angiogenesis. While expression of Id proteins has been associated with tumorigenesis, the precise mechanistic relationship between Id expression and carcinogenesis has not been clearly delineated. We have previously shown that Id1 delays cellular senescence in primary mammalian cells through inhibition of the cell cycle regulatory protein and familial melanoma gene, p16/INK4a. We have also demonstrated that Id1 expression is upregulated in early stage primary human melanomas and may be an important marker for early malignancy. In order to further define the role of Id1 in human melanoma development, we have evaluated the function of Id1 in primary human melanocytes. Here we show that constitutive expression of Id1 in primary human melanocytes leads to delayed cellular senescence and decreased expression of the familial melanoma gene, p16/INK4a. Although melanocytes constitutively expressing Id1 are shown to possess extended lifespans, this is not associated with an appreciable change in cell growth or telomere length. We conclude that Id1 delays cellular senescence in primary human melanocytes through inhibition of p16/INK4a expression and suggest that Id1 may contribute to the malignant conversion of primary human melanocytes through extension of cellular lifespan.
Cummings
Staci D
SD
The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231-1000, USA.
Ryu
Byungwoo
B
Samuels
Michael A
MA
Yu
Xiaobing
X
Meeker
Alan K
AK
Healey
Megan A
MA
Alani
Rhoda M
RM
D002455:Cell Division / Q000502:physiology*; D002465:Cell Movement; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology*; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology*; D052816:Foreskin / Q000166:cytology / Q000502:physiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D051798:Inhibitor of Differentiation Protein 1 / Q000235:genetics / Q000502:physiology*; D008297:Male; D008544:Melanocytes / Q000166:cytology* / Q000502:physiology*; D008745:Methylation; D011401:Promoter Regions, Genetic; D016615:Telomere / Q000235:genetics / Q000502:physiology
C497453:ID1 protein, human; D051798:Inhibitor of Differentiation Protein 1