ABSTRACT
BACKGROUND/AIMS: TRAIL-induced apoptosis was believed to occur in tumor cell lines, while not in normal cells, which suggested that TRAIL might be safe as an antitumor therapy. Some authors advocate that this exclusive TRAIL-induced apoptosis depended on whether or not TRAIL-R3 mRNA was expressed. In this study we investigated the difference in the expression of TRAIL and its receptors mRNA between human hepatocellular carcinoma (HCC) and surrounding liver tissues. METHODS: Intra-operative sampling of HCC and paired surrounding liver tissue was performed in 12 patients who underwent hepatic resection due to HCC. After RT-PCR, using total RNA extracts from the tissues, amplified RT-PCR, products were analyzed qualitatively for the expression of TRAIL and its receptors mRNA. Both tissues were compared semi-quantitatively for the expression of TRAIL-R3 mRNA with beta-actin using the method of Nicoletti et al. RESULTS: 1) TRAIL mRNA was expressed in HCC and surrounding liver tissues in all cases. 2) TRAIL-R1, -R2, and -R3 mRNA were also expressed in HCC and surrounding liver tissues in all cases. 3) The ratio of the expression of TRAIL-R3 mRNA to beta-actin mRNA was 0.22+/-0.15 in HCC and 0.34+/-0.21 in surrounding liver tissues (p=0.124, paired t-test). 4) TRAIL, TRAIL-R1, -R2 and -R3 mRNA were expressed in all HCC cases irrespective of the degree of tumor cell differentiation. CONCLUSIONS: TRAIL, TRAIL-R1, -R2, and TRAIL-R3 mRNA were expressed in all of the HCC and surrounding liver tissues. There was no quantitative difference in the expression of TRAIL-R3 mRNA between both tissues.