Affiliations: School of Studies in Biochemistry, Jiwaji University,
Gwalior-474011, India | Biochemistry & Molecular Biology Laboratory,
Center of Advanced Study in Zoology, Banaras Hindu University, Varanasi-221005,
India
Abstract: An increase in cell number is one of the most prominent
characteristics of cancer cells. This may be caused by an increase in cell
proliferation or decrease in cell death. Queuine is one of the modified base
which is found at first anticodon position of specific tRNAs. It is
ubiquitously present throughout the living system except mycoplasma and yeast.
The tRNAs of Q-family are completely modified to Q-tRNAs in terminally
differentiated somatic cells, however hypomodification of Q-tRNA is closely
associated with cell proliferation and malignancy. Queuine participates at
various cellular functions such as regulation of cell proliferation, cell
signaling and alteration in the expression of growth associated
proto-oncogenes. Like other proto-oncogenes bcl2 is known to involve in
cell survival by inhibiting apoptosis. Queuine or Q-tRNA is suggested to
inhibit cell proliferation but the mechanism of regulation of cell
proliferation by queuine or Q-tRNA is not well understood. Therefore, in the
present study regulation in cell proliferation by queuine in vivo and
in vitro as well as the expression of cell death regulatory protein Bcl2
are investigated. For this DLAT cancerous mouse, U87 cell line and HepG2 cell
line are treated with different concentrations of queuine and the effect of
queuine on cell proliferation and apoptosis are studied. The results indicate
that queuine down regulates cell proliferation and expression of Bcl2 protein,
suggesting that queuine promotes cell death and participates in the regulation
of cell proliferation.
