Cell cycle kinetics, apoptosis rates, DNA damage and TP53 geneexpression in bladder cancer cells treated with allyl isothiocyanate(mustard essential oil).

Abstract

Allyl isothiocyanate (AITC) is present in plants of the cruciferous family and is abundant in mustard seed.Due to its high bioavailability in urine after ingestion, AITC has been considered a promising antineoplasticagent against bladder cancer. Because TP53 mutations are the most common alterations in bladder cancercells and are frequently detected in in situ carcinomas, in this study, we investigated whether the AITCeffects in bladder cancer cells are dependent on the TP53 status. Two bladder transitional carcinoma celllines were used: RT4, with wild-type TP53; and T24, mutated TP53 gene. AITC was tested at concentrationsof 0.005, 0.0625, 0.0725, 0.0825, 0.0925, 0.125 and 0.25 _M in cytotoxicity, cell and clonogenic survivalassays, comet and micronucleus assays and for its effects on cell cycle and apoptosis by flow cytometry andon TP53 gene expression. The data showed increased primary DNA damage in both cell lines; however,lower concentrations of AITC were able to induce genotoxicity in the mutant cells for the TP53 gene.Furthermore, the results demonstrated increased apoptosis and necrosis rates in the wild-type cells, butnot in mutated TP53 cells, and cell cycle arrest in the G2 phase for mutated cells after AITC treatment.No significant differences were detected in TP53 gene expression in the two cell lines. In conclusion,AITC caused cell cycle arrest, increased apoptosis rates and varying genotoxicity dependent on the TP53status. However, we cannot rule out the possibility that those differences could reflect other intrinsicgenetic alterations in the examined cell lines, which may also carry mutations in genes other than TP53.Therefore, further studies using other molecular targets need to be performed to better understand themechanisms by which AITC may exert its antineoplastic properties against tumor cells.