Clinical significance of long intergenic noncoding RNA-p21 in colorectal cancer.

BACKGROUND

Long intergenic noncoding RNAs (lincRNAs) have been shown to be novel regulators for both transcription and posttranscriptional/translation. One of them, lincRNA-p21, was regulated by p53 and contributed to apoptosis in mouse embryonic fibroblasts. However, the impact of such regulation on colorectal cancer (CRC) remains to be determined.

METHODS

Total RNA was extracted from CRC cell lines and snap fresh frozen CRC samples from 2 CRC patient cohorts. The expression of lincRNA-p21 was quantified by quantitative real-time polymerase chain reaction analysis.

RESULTS

We discovered that the expression level of lincRNA-p21 was increased by elevated wild-type p53 induced by nutlin-3 in HCT-116 colon cancer cells. The expression level of lincRNA-p21 was significantly (P = .0208) lower in CRC tumor tissue when compared with the paired normal tissue from the same patient. There was no significant correlation of lincRNA-p21 with p53 status (wild-type vs. mutant). Tumors in the rectum showed a higher level of lincRNA-p21 than tumors in the colon (P = .00005). In addition, lincRNA-p21 in patients with stage III tumors was significantly higher than in those with stage I tumors (P = .007). Elevated levels of lincRNA-p21 were significantly associated with higher pT (P = .037 between pT 2 and 3) and vascular invasion (P = .017).

CONCLUSIONS

These results indicate that lincRNA-p21 may contribute to CRC disease progression.