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Melatonin delays cell proliferation by inducing G 1 and G 2 /M phase arrest in a human osteoblastic cell line hFOB 1.19
Author(s) -
Liu Lifeng,
Zhu Yue,
Xu Ying,
Reiter Russel J.
Publication year - 2011
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.2010.00832.x
Subject(s) - melatonin , cell cycle , cyclin dependent kinase 1 , cell growth , viability assay , cyclin d1 , cyclin b1 , endocrinology , osteoblast , biology , medicine , cyclin , cyclin e , cell culture , cell , biochemistry , in vitro , genetics
A recent prospective study indicated that melatonin supplements may reduce the progression of idiopathic scoliosis, the most common deformity of the spine. This form of scoliosis occurs during rapid skeletal growth. To date, however, there is no direct evidence regarding an antiproliferative effect of melatonin at the level of osteoblasts. Herein, we investigated whether melatonin inhibits cell proliferation in a normal human fetal osteoblastic cell line hFOB 1.19. MTT staining showed that at 1 m m concentrations, melatonin significantly inhibited osteoblast proliferation in time‐dependent manner. Flow cytometry demonstrated that melatonin significantly increased the fraction of cells in G 0 /G 1 phase of the cell cycle, while simultaneously reducing the proportion in the G 2 /M phase rather than the S phase. Western blot and real‐time PCR analyses further confirmed that melatonin’s inhibitory effect was possibly because of downregulation of cyclin D1 and CDK4, related to the G 1 phase, and of cyclin B1 and CDK1, related to the G 2 /M phase. There was no downregulation of cyclin E, CDK2, and cyclin A, which are related to G 1 /S transition and S phase. In addition, the trypan blue dye exclusion assay showed that cell viability was not changed by melatonin relative to control cells. These findings provide evidence that melatonin may significantly delay osteoblast proliferation in a time‐dependent manner and this inhibition involves the downregulation of cyclin D1 and CDK4, related to the G 1 phase, and of cyclin B1 and CDK1, related to the G 2 /M phase.