Eukaryotic
initiation factor 5A (eIF-5A) contains an unusual
amino acid,
hypusine, which is formed post-translationally. Although
eIF-5A and its
hypusine modification are essential for eukaryotic cell viability, the precise physiological function of it has remained elusive. The aim of the study is to investigate how
hypusine formation modulate the proliferation, cell cycle and apoptosis in leukaemia cells. The effects of
1,7-diaminoheptane (DAH), a potent inhibitor of
deoxyhypusine synthase, on proliferation and cell viability of
leukemia cell lines (Mo7e, TF-1 and THP-1) and MCF-7 cells, were investigated.
eIF-5A expression level was detected after cell synchronization. The results showed that inhibition of cell proliferation by DAH was in a concentration-dependent manner while apoptosis was also induced at the same time. Upon treatment of the cell lines with DAH, cell growth was inhibited. Cell cycle analysis showed that DAH induced cell growth arrest at the G(1)-S boundary of the cell cycle. In synchronized MCF-7 cells, the expression level of
eIF-5A peaked at G(1) phase but very low at S and G(2)/M phases. It is concluded that
hypusine formation of
eIF-5A exits in the regulation of cell cycle and the results suggest that
eIF-5A is involved in the expression of
proteins regulating transition of G(1)-S phase of cell cycle.