Tyrosine kinase inhibitor PTK/ZK enhances the antitumor effects of interferon-α/5-fluorouracil therapy for hepatocellular carcinoma cells.
OBJECTIVE
There is no standardized treatment for hepatocellular carcinoma (HCC) with portal vein tumor thrombus. We previously reported the efficacy of interferon-alpha and 5-fluorouracil combination (IFN/5-FU) therapy for these patients and the potential mechanism via the regulation of vascular endothelial growth factor (VEGF). In this study, we showed the VEGF-related effects of IFN/5-FU therapy using VEGF-receptor (VEGFR) selective inhibitor, PTK787/ZK222584 (PTK/ZK), in HCC cells.


METHODS
Using two VEGF secreting and VEGFR expressing human HCC cell lines, PLC/PRF/5 and HuH7, we performed growth inhibitory assays in vitro and in vivo, apoptosis assay, cell cycle analysis, and Western blot analysis for the mechanism, with or without PTK/ZK in IFN/5-FU therapy.


RESULTS
The combination of PTK/ZK and IFN/5-FU significantly inhibited cell growth in vitro and tended to reduce tumor growth in vivo in a HuH7 xenograft model in nude mice-in both cases without affecting VEGF secretion. PTK/ZK enhanced the IFN/5-FU induced apoptosis, based on increased proteins levels of Bax and reduced Bcl-xL and Bcl-2. Cell cycle analysis showed different results between the HCC cell lines following the combination therapy, possibly due to differences in p21 protein.


CONCLUSIONS
VEGF signaling inhibition would support an antitumor effect of IFN/5-FU therapy against HCC cell lines via induction of apoptosis and cell cycle delay.
Murakami
Masahiro
M
Department of Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan.
Kobayashi
Shogo
S
Marubashi
Shigeru
S
Tomimaru
Yoshito
Y
Noda
Takehiro
T
Wada
Hiroshi
H
Eguchi
Hidetoshi
H
Takeda
Yutaka
Y
Tanemura
Masahiro
M
Umeshita
Koji
K
Doki
Yuichiro
Y
Mori
Masaki
M
Nagano
Hiroaki
H
D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols; D000998:Antiviral Agents / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D005434:Flow Cytometry; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use*; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010793:Phthalazines / Q000627:therapeutic use*; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011725:Pyridines / Q000627:therapeutic use*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured
D000964:Antimetabolites, Antineoplastic; D000998:Antiviral Agents; D016898:Interferon-alpha; D010793:Phthalazines; D047428:Protein Kinase Inhibitors; D011725:Pyridines; C404768:vatalanib; D040262:Receptors, Vascular Endothelial Growth Factor; D005472:Fluorouracil