Phenethyl isothiocyanate potentiates anti-tumour effect of doxorubicin through Akt-dependent pathway

The present study aims to investigate the in vivo and in vitro anti-tumour properties of phenethyl isothiocyanate (PEITC) alone and in combination with doxorubicin (Dox). The anti-tumour activity was evaluated in vitro by MTT assay using cultured human breast cancer cell line (MCF-7) and human hepatoma cell line (HepG-2) cell lines. In vivo, Ehrlich solid tumour model was used. Tumour volume, weight and antioxidant parameters were determined. Immunohistochemistry analysis for active (cleaved) caspase-3 was also performed. We tested the effect of PEITC treatment on pAkt/Akt ratio, NF-κB p65 DNA binding activity and caspase-9 enzyme activity in both MCF-7 and HepG-2 cell lines. Effect of PEITC treatment on cell migration was assessed by wound healing assay. PEITC and/or Dox treatment significantly inhibited solid tumour volume and tumour weight when compared with control mice. PEITC treatment significantly reduced oxidative stress caused by Dox treatment as indicated by significant increase in total antioxidant capacity and decrease in malondialdehyde level. Microscopic examination of tumour tissues showed a significant increase in active (cleaved) caspase-3 expression in PEITC and/or Dox treated groups. PEITC showed a dose-dependent inhibition of MCF-7 and HepG-2 cellular viability. PEITC inhibited Akt and NF-κB activation and increased caspase-9 activity in a dose-dependent manner. PEITC treatment effectively inhibited both MCF-7 and HepG-2 cell migration. We can conclude that PEITC acts via multiple molecular targets to elicit anti-carcinogenic activity. PEITC/Dox combination therapy might be a potential novel strategy, which may benefit patients with breast and liver cancers.