Preclinical evaluation of combined TKI-258 and RAD001 in hepatocellular carcinoma.

Abstract

PURPOSE:

RAD001 targets at the mammalian target of rapamycin (mTOR), while TKI-258 is a potent tyrosine kinase inhibitor targeting at fibroblast growth factor receptor, vascular endothelial growth factor receptor, platelet-derived growth factor receptor and c-kit. We aim to study the activity of combined RAD001 and TKI-258 in cell lines and xenograft model of hepatocellular carcinoma (HCC), with reference to the parallel and upstream pathways of Akt-mTOR axis.

METHODS:

A panel of 4 human HCC cell lines HepG2, Hep3B, PLC/PRF/5 and Huh7 and the Hep3B-derived xenograft were treated with TKI-258 or/and RAD001, respectively. Related mechanistic studies (including apoptosis and angiogenesis) were conducted.

RESULTS:

There was an enhanced increase in suppression of cell proliferation with combined TKI-258 and RAD001 compared with either drug alone. The combination could significantly suppress the phosphorylation of mTOR, MEK1/2 and p38 MAPK. Although the addition of the TKI258 only slightly suppressed the phosphorylation of AKT induced by RAD001, the pi-mTOR and its downstream signaling pathways including pi-p70S6K, pi-S6 and pi-4EBP1 were lowered in the combination. In Hep3B-derived xenograft, TKI-258 and RAD001 had shown an enhanced inhibition of tumor growth without impact on the weight of animals. There was a reduction in microvessel density in the xenograft with the combination, which indicated an enhanced inhibition on angiogenesis. Pro-caspases-3 and PARP cleavage were slightly detected at 48 h after treatment, suggesting that the combination mainly increased the cytostatic arrest ability.

CONCLUSIONS:

The combination of RAD001 and TKI-258 was active in HCC via inhibition of both mTOR-mediated signaling and its parallel pathways.

• Authors: Stephen L Chan, Chi-Hang Wong, Cecilia P Y Lau, Qian Zhou, Connie W C Hui, Vivian W Y Lui, Brigette B Y Ma, Anthony T C Chan, Winnie Yeo
• Journal: Cancer chemotherapy and pharmacology (Cancer Chemother Pharmacol) Vol. 71 Issue 6 Pg. 1417-25 (Jun 2013) ISSN: 1432-0843 [Electronic] Germany
• PMID: 23546591 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 4-amino-5-fluoro-3-(5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2-yl)quinolin-2(1H)-one
• Benzimidazoles
• Quinolones
• Everolimus
• Proto-Oncogene Proteins c-akt
• TOR Serine-Threonine Kinases
• Sirolimus

Topics

• Animals
• Antineoplastic Combined Chemotherapy Protocols (administration & dosage, pharmacology, therapeutic use)
• Apoptosis (drug effects)
• Benzimidazoles (administration & dosage)
• Blotting, Western
• Carcinoma, Hepatocellular (blood supply, drug therapy, pathology)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Cell Survival (drug effects)
• Everolimus
• Humans
• Liver Neoplasms (blood supply, drug therapy, pathology)
• Mice
• Mice, Nude
• Neovascularization, Pathologic (drug therapy, pathology)
• Proto-Oncogene Proteins c-akt (antagonists & inhibitors)
• Quinolones (administration & dosage)
• Sirolimus (administration & dosage, analogs & derivatives)
• TOR Serine-Threonine Kinases (antagonists & inhibitors)
• Xenograft Model Antitumor Assays