ABSTRACT
Objective To screen the differentially expressed microRNAs (miRNAs) in colorectal cancer tissues with high expression of gastrin (GAS) by gene chip technique. Methods The level of GAS in tumor tissues from 71 patients with colorectal cancer was detected by enzyme linked immumosorbent assay (ELISA), and the relationship between positive expression of GAS and clinicopathological features was analyzed. Human colorectal cancer tissues with high positive GAS expression (high-expression group, n=4) or negative GAS expression (control group, n=4) were analyzed by miRNA microarray, and the selected differentially expressed miRNAs were validated by qPCR. Results There were 17 cases (23.9%) with GAS content ≥50.00 pg/g (positive GAS expression), while the remaining 54 cases (76.1%) had negative GAS expression. The expression level of GAS was related to the degree of differentiation, Dukes stage and histological type (P200.00 pg/g) compared with the control group, of which 159 miRNAs were up-regulated and 77 were down-regulated. A total of 24 miRNAs were screened out, which differentially expressed more than 3 folds in the high-expression group, with 17 up-regulated and 7 down-regulated. Three up-regulated or down-regulated miRNAs were selected for qPCR verification, and the results were consistent with the microarray analysis. Conclusion The miRNAs are differentially expressed in the colorectal cancer tissues with high expression of GAS, and they would be potential targets for the treatment of the colorectal cancer with high GAS expression.
ABSTRACT
<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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).</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>