miR-1266-3p Suppresses Epithelial-Mesenchymal Transition in Colon Cancer by Targeting P4HA3.

Numerous studies have been conducted to demonstrate that miRNA is strongly related to colon cancer progression. Nevertheless, there are few studies regarding the function for miR-1266-3p in colon cancer, and the molecular mechanism remains poorly know. Our study was designed to examine the level of miR-1266-3p expression among the colon cancer tissue and cell and to study the role and regulatory mechanism for miR-1266-3p among colon cancer's malignant biologic behavior. First, we found that miR-1266-3p expression was distinctly lower in colonic carcinoma tissues and cells than in nontumor ones, and the prognosis of low miR-1266-3p patients was distinctly worse than that of high miR-1266-3p patients. Second, we predicted that the target gene of miR-1266-3p was prolyl 4-hydroxylase subunit alpha 3 (P4HA3) through bioinformatics, and the targeting relationship between the two was verified by a dual luciferase assay report. Furthermore, miR-1266-3p inhibited the growth and metastasis of colon cancer in vitro as well as in vivo, and this effect could be alleviated by overexpressing P4HA3. Even more importantly, our study demonstrated that miR-1266-3p inhibited epithelial-mesenchymal transition (EMT) by targeting P4HA3. In conclusion, miR-1266-3p could inhibit growth, metastasis, and EMT in colon cancer by targeting P4HA3. Our discoveries might offer a novel target for colon cancer diagnosis and treatment.

Prolyl 4-hydroxylase subunit alpha 3 facilitates human colon cancer growth and metastasis through the TGF-ß/Smad signaling pathway.

Prolyl 4-hydroxylase subunit alpha 3 (P4HA3) has been known to be associated with a variety of human cancers. However, the role of P4HA3 on colon cancer growth and metastasis is unclear. In this study, we investigated the effect of P4HA3 on the growth and metastasis of colon cancer and its possible molecular mechanism. First of all, we demonstrated that P4HA3 expression was greatly higher in cells and tissues of colon cancer than that in non-tumor tissues and cells, and the prognosis of patients who had higher P4HA3 was distinctively poorer than patients who had lower level of P4HA3. Second, it was shown that P4HA3 knockdown strongly inhibited the migration, proliferation and invasion ability of colon cancer cells. However, P4HA3 over-expression accelerated the abilities. Meanwhile, P4HA3 could promote subcutaneous tumorigenesis in nude mice in vivo. In addition, P4HA3 knockdown significantly decreased mesenchymal markers Vimentin, N-cadherin and Snail expression and increased epithelial marker E-cadherin expression. And conversely, over-expression of P4HA3 produced the opposite effects. In the current study, there was further evidence that down-regulating P4HA3 significantly reduced both TGF-ß and its following molecules including p-Smad2 as well as p-Smad3. However, overexpression of P4HA3 showed the opposite effect. In conclusion, this study shows that P4HA3 promotes the human colon cancer growth and metastasis by affecting TGF-ß/Smad signaling pathway. P4HA3 may become a new target for early diagnosis, treatment and prognosis assessment of colon cancer.