Co-expression of the carbamoyl-phosphate synthase 1 gene and its long non-coding RNA correlates with poor prognosis of patients with intrahepatic cholangiocarcinoma

The mechanisms leading to high rates of malignancy and recurrence of human intrahepatic cholangiocarcinoma (ICC) remain unclear. It is difficult to diagnose and assess the prognosis of patients with ICC in the clinic due to the lack of specific biomarkers. In addition, long non-coding RNAs (lncRNAs) have been reported to serve important roles in certain types of tumorigenesis however a role in ICC remains to be reported. The aim of the current study was to screen for genes and lncRNAs that are abnormally expressed in ICC and to investigate their biological and clinicopathological significance in ICC. The global gene and lncRNA expression profiles in ICC were measured using bioinformatics analysis. Carbamoyl-phosphate synthase 1 (CPS1) and its lncRNA CPS1 intronic transcript 1 (CPS1-IT1) were observed to be upregulated in ICC. The expression of CPS1 and CPS1-IT1 was measured in 31 tissue samples from patients with ICC and a number of cell lines. The effects of CPS1 and CPS1-IT1 on the proliferation and apoptosis of the ICC-9810 cell line were measured. In addition, the clinicopathological features and survival rates of patients with ICC with respect to the gene and lncRNA expression status were analyzed. CPS1 and CPS1-IT1 were co-upregulated in ICC tissues compared with non-cancerous tissues. Knockdown of CPS1 andor CPS1-IT1 reduced the proliferation and increased the apoptosis of ICC-9810 cells. Additionally, clinical analysis indicated that CPS1 and CPS1-IT1 were associated with poor liver function and reduced survival rates when the relative expression values were greater than 4 in cancer tissues. The comparisons between the high CPS1 expression group and the low expression group indicated significant differences in international normalized ratio (P=0.048), total protein (P=0.049), indirect bilirubin (P=0.025), alkaline phosphatase (P=0.003) and disease-free survival (P=0.034). In addition, there were differential trends in CA19-9 (P=0.068), globulin (P=0.052) and total bilirubin (P=0.066). The comparisons between the high CPS1-IT1 expression group and the low expression group indicated significant differences in lymphatic invasion (P=0.045), carbohydrate antigen 19-9 (P=0.044), disease-free survival (P=0.026), and non-significant differential trends in alkaline phosphatase were observed (P=0.085). In conclusion, CPS1 and CPS1-IT1 may serve an important role in ICC development by promoting the proliferation of ICC cells. Furthermore, CPS1 and CPS1-IT1 were associated with poor liver function and reduced survival rates. Thus, CPS1 and CPS1-IT1 may be potential prognostic indicators for patients with ICC.