Overexpression of mRNA-decapping enzyme 1a affects survival rate in colorectal carcinoma

Abstract

Processing bodies (P-bodies) are one of the most well understood types of RNA granules, and are associated with a variety of diseases, including cancer. mRNA-decapping enzyme 1a (DCP1a), which may be used as a marker to analyze P-bodies, participates in the removal of the 5'-methylguanosine cap from eukaryotic mRNAs as a cofactor. The aim of the present study was to analyze the association between DCP1a expression and clinical features in colorectal carcinoma (CRC). The levels of DCP1a mRNA expression were detected by reverse transcription-quantitative polymerase chain reaction assay in carcinoma and non-carcinoma tissues from 75 patients, while the protein expression levels were evaluated by immunohistochemistry and western blotting. Additional associations between DCP1a expression and clinical characteristics were analyzed by χ² test and Cox regression analysis. In the 75 cases, the levels of DCP1a mRNA and protein expression were increased in colorectal carcinoma tissues compared with non-carcinoma tissues. A high expression of DCP1a was significantly associated with lower survival rates in patients with CRC compared with patients with low DCP1a expression (P=0.001). Associations with depth of invasion (P=0.008), lymph node metastasis (P=0.001) and tumor node metastasis stage (P=0.001) were also observed. Additional Cox regression analysis revealed that the DCP1a expression (P=0.012) is an independent factor in survival rate. It was also identified that DCP1a may have high expression in colorectal carcinoma tissues and be associated with poor prognosis. This suggests that DCP1a may be a diagnostic marker or prognostic indicator to assist with patient assessments and therapies.

Keywords: colorectal carcinoma; mRNA-decapping enzyme 1a; prognostic indicator; survival rate.

Figure 1.

Relative mRNA level of DCP1a in colorectal carcinoma and non-carcinoma tissues by reverse transcription quantitative polymerase chain reaction, and analyzed by Student's t-test. The relative level of DCP1a mRNA identified in carcinoma tissues was significantly increased compared with that in non-carcinoma tissues. Experiments were repeated three times (**P=0.0024). DCP1a, mRNA-decapping enzyme 1a.

Figure 2.

DCP1a protein expression in colorectal carcinoma and non-carcinoma tissues. (A) Immunohistochemical staining indicated that the level of DCP1a protein was visibly increased in carcinoma tissues compared with the non-carcinoma tissues (magnification, ×100). (B) Western blotting was performed to detect the levels of DCP1a, and representative gels of 3 patients are presented. All the experiments were repeated 3 times. DCP1a, mRNA-decapping enzyme 1a; NT, normal tissue; CT, carcinoma tissue.

Figure 3.

Overall survival of 118 patients with colorectal carcinoma in association with DCP1a expression levels. All patients with CRC were divided into high expression (n=86) and low expression (n=32) groups. The levels of DCP1a expression were compared with the normal tissues. Survival curves were analyzed by log-rank tests. The survival rate in the high-expression group was significantly decreased in comparison with that in the low-expression group (P=0.001).