Rotundic Acid Regulates the Effects of Let-7f-5p on Caco2 Cell Proliferation

Background & Objective: Nowadays, the interaction between natural products and microRNAs provides a promising field for exploring the chemo preventive agents for various cancers.As a member of microRNAs, the expression of let-7f-5p is universally down regulated in colorectal cancer (CRC). The present study aimed to uncover the function of let-7f-5p in the proliferation of human colon cancer cell line Caco2 and explored chemo preventive agents from natural resources that can prevent the development of CRC. Methods: Herein, Caco2 cells were transfected with let-7f-5p mimic and inhibitor to manipulate let-7f-5p levels, and the expression of let-7f-5p wasper formed by RT‑qPCR. Next, we determined how let-7f-5p regulates Caco2 cell proliferation by using MTT, wound-healing, cell cycle,and colony formation assays.Besides, to further understand the effect of let-7f-5p, we evaluated the protein level of AMER3 and SLC9A9 by using western blotting assays. Results: The results showed a suppressive function of let-7f-5p on Caco2 cell proliferation and then put forward a triterpenoid (rotundic acid, RA) which significant antagonized the effect of cell proliferation, restitution after wounding,and colony formation caused by let-7f-5p. Moreover, the western blot results further indicated that the inhibitory effect of RA might be due to its suppressive role in let-7f-5p-targeted AMER3 and SLC9A9 regulation. Conclusion: Our validation study results confirmed that let-7f-5p was a potent tumor suppressor gene of Caco2 cell proliferation,and RA showed as a regulator of the effect oflet-7f-5p on cell proliferation and then could be a potential chemo preventive agent for CRC treatment.