Relationship between the expression of cyclooxygenase-2, inhibitor of apoptosis proteins and chemosensitivities in gastrointestinal carcinomas

Objective To investigate the re'ationship between the expression of cyclooxygenase-2 (COX-2), inhibitor of apoptosis proteins (IAPs, including p53, Survivin, bcl-2) and chemosensitivities in gastrointestinal carcinomas. Methods The expression of COX-2 ,p53, Survivin and bcl-2 was detected immunohistochemically, and the chemosenisitivities of 9 drugs was measured by MTT assay in 84 tissue specimens of gastrointestinal carcinomas. Results The positive expression rate of COX-2, p53, Survivin and bcl-2 was 70.3% ,64. 3% ,89. 3% and 60.7% respectively. There was a significant correlation between the expression of COX-2 and Survivin, and COX-2 and bcl-2 (r=0. 5072,0. 3783, both P<0. 01). In terms of relationship between the expression of four MDR-related factors and inhibition rate of tumor cells, the inhibition rate for PTX,eADM and OPT in COX-2 strong expression group was lower than that in weak group (all P<0.05). The inhibition rate to PTX and DDP was significantly lower in the p53 strong expression group than in the weak group (both P<0.05). When Survivin was expressed strongly,the inhibition rate for VCR and DDP was reduced significantly (both P<0.05). There was the lower inhibition rate for 5-Fu,VCR,eADM and OXA in bcl-2 strong expression group (all P<0. 05). Conclusion COX-2 could participate in MDR of gastrointestinal carcinomas by inhibiting the apoptosis of tumor cells. Key words: Gastrointestine tumors; Multidrug resistance; Cyclooxygenase-2; Inhibitor of apoptosis proteins