[Down-regulation of survivin in growth inhibition of hepatoma cells induced by a selective cyclooxygenase-2 inhibitor].

Background/aims: Cyclooxygenase-2 (COX-2) inhibitors reportedly inhibit the growth of hepatocellular carcinoma (HCC) via caspase-dependent or caspase-independent apoptosis, which is due to COX-2 being associated with hepatocarcinogenesis. Survivin is highly expressed in most human cancers, but the mechanism regulating survivin expression remains unclear. We investigated the regulatory expression of survivin in selective-COX-2-inhibitor-induced growth inhibition of hepatoma cells.
Methods: After treatment with NS-398 (a selective COX-2 inhibitor) at various concentrations (10, 50, 100, 150, and 200 micrometer), the growth inhibition of Hep3B hepatoma cells was assessed by an MTT cell-viability assay, DNA fragmentation gel analysis, and flow cytometry. The expression of survivin transcript was analyzed by reverse-transcription polymerase chain reactions.
Results: NS-398 inhibited the growth of hepatoma cells by an amount dependent on the concentration and the time since treatment. Apoptotic DNA ladder and flow-cytometry shifting to the sub-G1 phase were revealed in NS-398-induced growth inhibition of hepatoma cells. NS-398 suppressed the expression of the survivin gene in a concentration- and time-dependent manner.
Conclusions: Survivin was down-regulated in the growth inhibition of hepatoma cells induced by a selective COX-2 inhibitor, NS-398, in a concentration- and time-dependent manner. These results suggest the therapeutic inhibition of COX-2 via suppression of survivin in HCC.