Accelerated degradation of caspase-8 protein correlates with TRAIL resistance in a DLD1 human colon cancer cell line

Lidong Zhang, Hongbo Zhu, Fuminori Teraishi, John J. Davis, Wei Guo, Zhen Fan, Bingliang Fang

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The tumor-selective cytotoxic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL.) makes TRAIL an attractive candidate as an anticancer agent. However, resistance to TRAIL poses a challenge in anticancer therapy with TRAIL. Therefore, characterizing the mechanisms of resistance and developing strategies to overcome the resistance are important steps toward successful TRAIL-mediated cancer therapy. In this study, we investigated mechanisms of acquired TRAIL resistance in a colon cancer DLD1 cell line. Compared with the TRAIL-susceptible DLD1 cell line, TRAIL-resistant DLD1/TRAIL-R cells have a low level of caspase-8 protein, but not its mRNA. Suppression of caspase-8 expression by siRNA in parental DLD1 cells led to TRAIL resistance. Restoration of caspase-8 protein expression by stable transfection rendered the DLD1/TRAIL-R cell line fully sensitive to TRAIL protein, suggesting that the low level of caspase-8 protein expression might be the culprit in TRAIL resistance in DLD1/TRAIL-R cells. Sequencing analysis of the caspase-8 coding region revealed a missense mutation that is present in both TRAIL-sensitive and TRAIL-resistant DLD1 cells. Subsequent study showed that the degradation of caspase-8 protein was accelerated in DLD1/TRAIL-R cells compared to parental DLD1 cells. Thus, accelerated degradation of caspase-8 protein is one of the mechanisms that lead to TRAIL resistance.

Original languageEnglish
Pages (from-to)594-602
Number of pages9
Issue number6
Publication statusPublished - Jun 2005
Externally publishedYes


  • Apoptosis
  • Caspase-8
  • Degradation
  • Resistance

ASJC Scopus subject areas

  • Cancer Research


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