Phenethyl Isothiocyanate Induces Apoptotic Cell Death Through the Mitochondria-dependent Pathway in Gefitinib-resistant NCI-H460 Human Lung Cancer Cells In Vitro

Abstract

Background/aim: Some lung cancer patients treated with gefitinib develop resistance to this drug resulting in unsatisfactory treatment outcomes. Phenethyl isothiocyanate (PEITC), present in our common cruciferous vegetables, exhibits anticancer activities in many human cancer cell lines. Currently, there is no available information on the possible modification of gefitinib resistance of lung cancer in vitro by PEITC. Thus, the effects of PEITC on gefitinib resistant lung cancer NCI-H460 cells were investigated in vitro.

Materials and methods: The total cell viability, apoptotic cell death, production of reactive oxygen species (ROS) and Ca²⁺, levels of mitochondria membrane potential (ΔΨ_m) and caspase-3, -8 and -9 activities were measured by flow cytometry assay. PEITC induced chromatin condensation was examined by DAPI staining.

Results: PEITC-induced cell morphological changes, decreased total viable cell number and induced apoptotic cell death in NCI-H460 and NCI-H460/G cells. PEITC decreased ROS production in NCI-H460 cells, but increased production in NCI-H460/G cells. PEITC increased Ca²⁺ production, decreased the levels of ΔΨ_m and increased caspase-3, -8 and -9 activities in both NCI-H460 and NCI-H460/G cells. Western blotting was used to examine the effect of apoptotic cell death associated protein expression in NCI-H460 NCI-H460/G cells after exposure to PEITC. Results showed that PEITC increased expression of cleaved caspase-3, PARP, GADD153, Endo G and pro-apoptotic protein Bax in NCI-H460/G cells.

Conclusion: Based on these results, we suggest that PEITC induces apoptotic cell death via the caspase- and mitochondria-dependent pathway in NCI-H460/G cells.

Keywords: NCI-H460 human lung cancer cells; Phenethyl isothiocyanate; apoptosis; gefitinib.