Objective: To investigate the inhibitory effect of RGDRGD-ES on HUVEC in vitro. Methods:A modified human
endostatin gene containing RGDRGD motif was obtained by rapid site-directed mutagenesis. The RGD mutated endostatin gene was
expressed by a prokaryotic expression vector and purified by Ni-NTA resin. Automated gene sequencing and Western blot analysis were
used to identify RGDRGD-ES gene and protein respectively. HUVEC cultured in vitro were exposed to RGDRGD-ES protein at different
concentrations (0 μg/ml,10 μg/ml,20 μg/ml,30 μg/ml,40 μg/ml,50 μg/ml) and ES at 30 μg/ml for different time duration (24 h,48 h,72
h,96 h). Cell viabilities were monitored by 3,4,5dimethyliazol-2,5diphenyltetrazolium bromide (MTT) assay. The apoptosis rates at 24 h
were detected by flow cytometric analysis. Results:Modified endostatin gene containing RGDRGD motif was confirmed by automated
gene sequencing. The prokaryotic expression vector containing RGDRGD-ES was successfully constructed,and RGDRGD-ES expression
was identified by Western blot. RGDRGD-ES clearly reduced HUVEC viability compared to control group (P<0.01) and ES group (P<0.
01). RGDRGD-ES induced loss of cell viability by a dose dependant manner among 10 μg/ml,20 μg/ml,30 μg/ml groups(P<0.01), while
no significant differences were found in 30 μg/ml ,40 μg/ml,50 μg/ml groups (P<0.01). RGDRGD-ES also induced loss of cell viability
by a time dependant manner within 72 h (P<0.01), however, there was no significant difference between 72 h and 96 h (P>0.05).
Consistent with MTT assay, RGDRGD-ES induced HUVEC apoptosis by a dose dependant manner among 10 μg/ml,20 μg/ml,30 μg/ml
groups (P<0.01), while no significant differences were found in 40 μg/ml,50 μg/ml groups (P>0.05). Conclusion:RGDRGD-ES can be
obtained by rapid site-directed mutagenesis and prokaryotic expression vector. RGDRGD-ES inhibits HUVEC cell viability and induces
cell apoptosis significantly. The optimal dose and time of RGDRGD-ES incubation are 30 μg/ml and 72 h. Modified endostatin with the
RGDRGD motif is more effective than ES in inhibition of HUVEC cell viability and induction of HUVEC cell apoptosis. |