<p><b>OBJECTIVE</b>To investigate the
therapeutic value of inhibiting the expression of
insulin-like growth factor-I receptor (IGF-IR) using picropodophyllin (PPP) by studying the effects on proliferative and metastatic potentials of
human hepatocellular carcinoma (HCC) using an
in vitro cultured cell system.</p><p><b>
METHODS</b>IGF-IR expression in
human HCC
cell lines (Bel-7404, Bel-7402, HepG2, and Huh-7) and
human hepatocytes (L02) was assessed at baseline (pre-
treatment) and after PPP
treatment by
western blotting. Changes in
cell cycle were analyzed by
flow cytometry and in
cell viability by sulforhodamine B
staining. Early
apoptosis was detected by
annexin-V/
FITC and
propidium iodide double-
staining assay.
Caspase-3/7 activity was suppressed by z-VAD-FMK and analyzed by homogeneous
luminescence assay. Effects on
cell motility were tested by
wound-scratch test. Between-group differences were assessed by t-test or one-way
analysis of variance.</p><p><b>RESULTS</b>IGF-IR was markedly up-regulated in all HCC
cell lines (vs. non-
hepatoma hepatocytes). HCC
cells with PPP-inhibited IGF-IR showed
time-dependent decreases in
cell motility and viability.
After treatment with PPP for 24 hours, the proportion of HCC
cells in
G1 phase was 2.1% +/- 0.4%, in
S phase was 11.0% +/- 0.7%, and in G2/
M phase was 87.1% +/- 0.6%, and no healing was observed in the
wound-scratch assay. The PPP
treatment induced
cell apoptosis, as evidenced by enhanced
caspase-3/7 activity; the proportion of
annexin-V+/PI-
cells was significantly higher in the
HepG2 cells than in the non-
hepatoma hepatocytes (16.4% +/- 0.4% vs. 5.8% +/- 0.2%, t = 14.05, P less than 0.01). After z-VAD-FMK
treatment, the
apoptosis rate was significantly higher in the
HepG2 cells than in the non-
hepatoma hepatocytes (11.3% +/- 0.7% vs. 5.8% +/- 0.2%, t = 11.83, P less than 0.01).</p><p><b>CONCLUSION</b>IGF-IR is associated with
proliferation, cell motility, and
apoptosis of HCC
cells, and may be a promising molecular target for HCC.</p>