ABSTRACT
BACKGROUND: Tumor necrosis factor-associated protein 1 (TRAP1) is a heat-shock protein 90-related mitochondrial chaperone. Accumulative evidence has demonstrated that TRAP1 overexpression is closely related to carcinogenesis. However, the exact function and mechanism of TRAP1 in the occurrence of laryngeal carcinoma remains unclear. OBJECTIVE: To investigate whether RNA interference can inhibit TRAP1 overexpression and to explore its effects on growth and apoptosis of CD133+CD44+ laryngeal carcinoma stem cells. METHODS: CD133+CD44+ laryngeal carcinoma stem cells were sorted from human laryngeal carcinoma Hep-2 cellsusing immunomagnetic beads. The shRNA sequence of TRAP1 was designed and synthesized and CD133+CD44+ laryngeal carcinoma stem cells were transfected with LipofectamineTM 2000. Cell counting kit-8 assay, colony formation assay and flow cytometry were used to investigate the effects of interference of TRAP1 expression on growth and apoptosis of CD133+CD44+ laryngeal carcinoma stem cells. Spectrophotometric method was used to detect the activity of caspase-3, -8 and -9. RESULTS AND CONCLUSION: TRAP1 mRNA and protein expression levels were significantly decreased in TRAP1 shRNA-transfected CD133+CD44+ laryngeal carcinoma stem cells (P < 0.01). Compared with the blank control and negative control groups, the growth and colony formation of CD133+CD44+ laryngeal carcinoma stem cells were significantly inhibited in the TRAP1 shRNA-transfected group (P < 0.05). Apoptosis of CD133+CD44+ laryngeal carcinoma stem cells was significantly inhibited in the TRAP1 shRNA-transfected group as compared with the blank control and negative control groups (P < 0.05). TRAP1 shRNA-mediated cell apoptosis was associated with the activation of caspase-3, -8 and -9. These results suggest that RNA interference targeting inhibition of TRAP1 suppresses cell growth but promotes apoptosis in CD133+CD44+ aryngeal carcinoma stem cells. TRAP1 is likely to be a gene target for treatment of laryngeal carcinoma.