Long non‑coding RNA RP11‑400N13.3 promotes the progression of colorectal cancer by regulating the miR‑4722‑3p/P2RY8 axis

Accumulating evidence has shown that long non-coding RNAs (lncRNAs) play significant roles in the development and progression of many types of cancer including colorectal cancer. RP11-400N13.3 is a novel lncRNA discovered recently and its biological function and underlying mechanism in colorectal cancer remain elusive. This study aimed to reveal the relationship between RP11-400N13.3 and colorectal cancer. Our results demonstrated that the expression of RP11-400N13.3 was significantly upregulated in both colorectal cancer tissues and cell lines as compared to normal adjacent tissues and normal colonic epithelial cells by RT-qPCR, respectively. Upregulation of RP11-400N13.3 was found to be correlated with a poor overall survival rate. Functional studies revealed that RP11-400N13.3 facilitated the proliferation, migration, invasion and tumor growth of colorectal cancer cells while inhibiting the apoptosis of cancer cells in vitro and in vivo. We also observed that RP11-400N13.3 serves as a sponge for miR-4722-3p, and that P2Y receptor family member 8 (P2RY8) was predicted to be a target of miR-4722-3p by bioinformatics analysis. Western blot assay indicated that the expression of P2RY8 was negatively or positively regulated by miR-4722-3p or RP11-400N13.3. In addition, rescue experiments revealed that RP11-400N13.3 promoted proliferation, migration and invasion by directly regulating the expression of miR-4722-3p and P2RY8. In conclusion, our results revealed that RP11-400N13.3 promoted colorectal cancer progression via modulating the miR-4722-3p/P2RY8 axis, thus suggesting RP11-400N13.3 as a potential therapeutic target for the treatment of colorectal cancer. Key words: RP11-400N13.3, colorectal cancer, miR-4722-3p, P2RY8