Relationships of the mRNA and protein expression of gastrin with Fas/FasL and caspases in colorectal carcinoma

Abstract

To examine the correlation between the mRNA and proteins expressions of gastrin(GAS), and the association of protein expression of GAS with apoptosis index(AI) and apoptosis regulation gene Fas/FasL, caspases in colorectal cancer. The expressions of GAS mRNA in tumor tissues of 79 cases with colorectal cancer were detected by nested RT-PCR. Cell apoptosis was detected by molecular biology in situ apoptosis detecting technic(TUNEL). Protein expressions of GAS, Fas/FasL, and caspases were detected by immunohistochemical staining (SP method). The positive correlation was found between the mRNA and proteins expressions of GAS(rGAS=0.99, P<0.01). The mRNA and protein expressions of GAS in well and moderately differentiated cancers were significantly lower than those in poorly differentiated cancers (chi(2)(high vs low)=10.47, 10.23, P<0.01, chi(2)(middle vs low)=6.68, 4.95, P<0.05). The mRNA and protein expressions of GAS in papillary and tubular adenocarcinomas were significantly lower than those in mucinous adenocarcinomas, signet-ring cell carcinoma and undifferentiated carcinoma (chi(2)(papillary vs mucinous and signet-ring)=4.80, 6.22, chi(2)(papillary vs undifferentiation)=5.44, 8.43, chi(2)(tubular vs mucinous and signet-ring)=4.40, 4.38, chi(2)(tubular vs undifferentiation)=4.92, 6.43, P<0.05, respectively). The mRNA and protein expressions of GAS in Dukes' stages A, B were significantly lower than those in Dukes stages C, D (chi(2)=4.84, 4.45, P<0.01). The AI in GAS high and moderate expression groups of colorectal cancer were significantly lower than that in low expression group (q(high vs low)=6.71, q(middle vs low)=4.60, P<0.01). The positive expression rate of FasL was significantly different among GAS high, moderate and low expression groups of colorectal cancer (chi(2)=9.35, P<0.01). The positive expression rate of FasL in GAS high and moderate expression groups was higher than that in low expression group (chi(2)high vs low=6.24, chi(2)(middle vs low)=4.74, P<0.05). GAS plays an important role in the regulation of cell apoptosis in colorectal carcinoma, whose mechanism may be related to the aberrant expression of Fas/FasL. GAS will be one of the indicators of the biological behavior in colorectal carcinoma.