Long-Term Treatment of Advanced Hepatocellular Carcinoma with the Tyrosine Kinase Inhibitor Erlotinib (Tarceva®) – A Case Report

Titanium Oxide Nanoparticles Improve the Chemotherapeutic Action of Erlotinib in Liver Cancer Cells

Background:

Hepatocellular carcinoma is the second leading cause of cancer-related deaths among other types of cancer due to lack of effective treatments and late diagnosis. Nanocarriers represent a novel method to deliver chemotherapeutic drugs, enhancing their bioavailability and stability.

Methods:

In the present study, we loaded gold nanoparticles (AuNPs) and titanium oxide nanoparticles (TiO2NPs) with ERL to investigate the efficiency of the formed composite in inducing apoptosis in HepG2 liver cancer cells. Cytotoxicity was assessed using MTT assay and cell phase distribution was assessed by flow cytometry along with apoptosis detection.

Results:

Data obtained indicated the efficiency of the formed composite to significantly induce cell death and arrest cell cycle and G2/M phase. IRF4 was downregulated after treatment with loaded ERL.

Conclusion:

Our data showed that loading ERL on TiO2NPs was more efficient than AuNPs. However, both nanocarriers were efficient compared with control.

Oxidative stress mediates an increased formation of vascular endothelial growth factor in human hepatocarcinoma cells exposed to erlotinib

The tyrosine kinase inhibitor erlotinib targets the receptor of epidermal growth factor (EGFR) involved in development of hepatocellular carcinoma (HCC).

Although inefficient in established HCC, erlotinib has been recently proposed for HCC chemoprevention. Since Cyp3A4 and Cyp1A2 enzymes metabolize erlotinib in the liver, the insights into the mechanisms of erlotinib effects on liver cells with maintained drug metabolizing activity are needed.

We applied erlotinib to both commercially available (SNU398, Huh7) and established in Austria HCC cell lines (HCC-1.2, HCC-3). Cyp3A4 and Cyp1A2, microarray gene expression, cell viability, LDH release, DHFC fluorescence were assessed. VEGF expression was analysed by real-time RT-PCR and ELISA.

Higher cumulative expression of erlotinib metabolizing enzymes was observed in HCC-1.2 and HCC-3 cells. Gene expression microarray analysis showed upregulation of VEGF signalling by erlotinib. VEGF was increased up to 134 ± 14% (n = 5, p = 0.002) in HCC-1.2, HCC-3 and Huh7 cells. Interventions by Cyp1A2 and Mek2siRNA, MEK inhibitor UO126, diphenylene iodonium, as well as a combination of N-acetylcysteine with selenium all inhibited VEGF upregulation caused by erlotinib.

Thus, erlotinib increases VEGF production by mechanisms involving Cyp1A2, oxidative stress and MEK1/2. VEGF may favour angiogenesis and growth of early HCC tumours limiting the therapeutic and chemopreventive effects of erlotinib.