Effect of sorafenib combined with cytostatic agents on hepatoblastoma cell lines and xenografts

Abstract

Background:Sorafenib has recently been shown to reduce tumour growth in hepatoblastoma (HB) xenografts. The effect of a combined administration with cytostatic agents was now investigated.Methods:Cell viability after treatment with sorafenib and different cytostatic agents was evaluated in two HB cell lines (HUH6 and HepT1) using MTT assay. ERK signalling was investigated by western blot, NOXA expression by rt-PCR, and formation of DNA adducts using immunocytology. NMRI mice bearing subcutaneous HUH6-derived tumours were treated with sorafenib alone or in combination with cisplatin. Tumour progression, viability, apoptosis, and vascularisation were monitored by tumour volume, AFP levels, TUNEL assay, and CD31 immunostaining, respectively.Results:The combination of sorafenib and cisplatin led to a remarkable decrease in cell viability. The cisplatin-induced enhanced ERK1/2 activation, but not NOXA expression and the formation of DNA adducts was partly abrogated by sorafenib. In HB xenografts, both, sorafenib and alternated application of sorafenib and cisplatin significantly reduced tumour growth (P<0.05). Levels of AFP were lower in both treated groups (P=0.08). Relative apoptotic areas were increased (P=0.003). Mean vascular density was the lowest in the sorafenib/CDDP group (P=0.02).Conclusion:The combination of sorafenib with cisplatin might be a promising treatment option for high risk or recurrent HB.

Anti-tumor activity of sorafenib in a model of a pediatric hepatocellular carcinoma

“…Growth inhibition of 50% was assessed at nearly the same concentrations found in the HB cell lines HUH6 and HepT1. Western blot analyses confirmed potent inhibition of the Raf/MEK/ ERK signaling pathway in HC-AFW1 cells as well as in tumor xenografts, which is known to be the key mechanism of inhibiting cell proliferation by sorafenib, already described for the aHCC cell lines PLC/PRF/5, Huh7 as well as for HB cell lines [15,16,22].…”

“…To evaluate tumor response, tissue histology and mean vascular density (MDV) were performed as previously described [15,16]. Capillaries were revealed by CD31-immunostaining using the monoclonal rat anti-mouse CD31 antibody (1:20; Dianova, Hamburg, Germany) and the Avidin-biotin-peroxidase-complex (Linaris, Wertheim, Germany) according to manufacturer's protocol.…”

“…Cells were stimulated with 10% FCS for 10 min before lysis or were left untreated. ERK and phosphorylated ERK (pERK) were assessed using electrophoresis and western blot as previously described [15,16].…”

“…Inhibiting angiogenesis and signal transduction through the Raf/Mek/ERK pathway, sorafenib was approved for treatment of liver and renal carcinoma in adults [13,14]. Moreover, sorafenib also showed a high anti-tumoral activity in pediatric liver tumors like Hepatoblastoma in preclinical studies [15,16]. A pilot study considered sorafenib in combination with cisplatin and doxorubicin in pHCC [7].…”

Synergistic growth inhibition by sorafenib and cisplatin in human osteosarcoma cells

“…ERK and its upstream kinase MEK localize to the extraluminal face of autophagosomes and ERK phosphorylation is upregulated by lipidation of autophagic protein LC3 (32). It has been shown that the treatment of various types of cancer, such as ovarian carcinoma (33), melanoma (34), and liver cancer cells (35) with CDDP caused ERK activation and cell death, and this latter effect was potentiated by ERK inhibitors, indicating that ERKs behave as survival-inducing kinases in these cells. Consistent with those results, our study has shown that CDDP caused ERK activation in Saos-2 cells.…”