To investigate the combined effect of
human recombinant soluble TNF-related
apoptosis induced
ligand (hrsTRAIL) with
Ara-C or alone on HL-60
leukemia cell lines and its mechanism,
human leukemia cell lines HL-60 were cultured
in vitro.
HL-60 cells were divided into 5 groups
control group,
Ara-C group, rsTRAIL group,
Ara-C + rsTRAIL simultaneously given group,
Ara-C + rsTRAIL tandem given group (
Ara-C followed by rsTRAIL group). The cytotoxic effect was measured by MTT assay;
cell apoptosis rate was determined by
flow cytometry after
Annexin V/PI
staining; the expression level of DR5 on surface of
HL-60 cells treated with
Ara-C at different concentrations for 24 hours was determined by
flow cytometry. The expression level of DR5 on surface of
HL-60 cells and
caspase-8 activity in
HL-60 cells of rsTRAIL group and
Ara-C + rsTRAIL tandem group was determined by
flow cytometry. The result showed that rsTRAIL could inhibit the proliferation of
HL-60 cells and induce
apoptosis of
HL-60 cells in a concentration-dependent manner. The
apoptosis rate of
HL-60 cells in
Ara-C + rsTRAIL tandem given group was higher than that in
Ara-C + rsTRAIL simultaneously given group, the expression level of DR5 on surface of
HL-60 cells and intracellular activity of
caspase-8 in
Ara-C + rsTRAIL tandem given group were higher than those in rsTRAIL group. When
HL-60 cells treated with 5 and 10 mg/L of
Ara-C for 24 hours, the expression level of DR5 on surface of
HL-60 cells was higher than that in
control group. It is concluded that rsTRAIL can inhibit the proliferation of
HL-60 cells, and induce
apoptosis of
HL-60 cells.
Ara-C can upregulate DR5 expression on the surface of
HL-60 cells and enhance the effect of rsTRAIL-inducing
apoptosis. Tandem
treatment of
HL-60 cells with
Ara-C followed by rsTRAIL induce more
apoptosis than that of co-
treatment with rsTRAIL and
Ara-C.
Ara-C and rsTRAIL has a synergistic inhibitory effect on
growth of
HL-60 cells. The mechanism may correlate with
up-regulation of the expression level of DR5 and/or
caspase-8 in
HL-60 cells by
Ara-C.