Thymoquinone induces apoptosis through downregulation of c-FLIP and Bcl-2 in renal carcinoma Caki cells

Oncol Rep. 2016 Oct;36(4):2261-7. doi: 10.3892/or.2016.5019. Epub 2016 Aug 12.

Abstract

Renal carcinoma is a common and frequently fatal carcinoma occurring worldwide and death rates due to this carcinoma are increasing with time. In the present study, we investigated the potential of thymoquinone a natural compound to induce apoptosis in renal carcinoma Caki cells. Thymoquinone efficiently enhanced the apoptotic population of Caki cells in a dose-dependent manner. Moreover, thymoquinone-mediated apoptosis caused downregulation of c-FLIP and Bcl-2, the master regulators of the anti-apoptotic mechanism. However, we did not find any changes in mRNA expression level of c-FLIP, therefore; this regulation of c-FLIP was a result of post-translation modification by thymoquinone. In contrast, expression of the Bcl-2 protein was observed at both transcriptional and translational level. However, we also observed that thymoquinone enhanced the level of intracellular reactive oxygen species (ROS) in Caki cells, which resulted in reduction of mitochondrial membrane potential (MMP) and cytochrome c release into cytoplasm. Our results postulate that thymoquinone induces apoptosis through downregulating c-FLIP and Bcl-2 which can be utilized as a chemotherapeutic agent to treat renal carcinoma.

MeSH terms

  • Apoptosis / drug effects*
  • Benzoquinones / administration & dosage*
  • CASP8 and FADD-Like Apoptosis Regulating Protein / biosynthesis*
  • CASP8 and FADD-Like Apoptosis Regulating Protein / genetics
  • Carcinoma, Renal Cell / drug therapy*
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / pathology
  • Cell Line, Tumor
  • Cytochromes c / genetics
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Membrane Potential, Mitochondrial / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • RNA, Messenger / biosynthesis
  • Reactive Oxygen Species / metabolism

Substances

  • Benzoquinones
  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • CFLAR protein, human
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • Reactive Oxygen Species
  • Cytochromes c
  • thymoquinone