Active monomer rtr-1 derived from the root of rhodomyrtus tomentosa induces apoptosis in gastric carcinoma cells by inducing er stress and inhibiting the stat3 signaling pathway

Abstract

Purpose: Rhodomyrtus tomentosa, aflowering plant from the Myrtaceae family, is con-sidered an antitumour substance with versatile biological and pharmacological activities. RTR-1 is an active monomer purified from the root of Rhodomyrtus tomentosa. However, the detail of mechanism involving in RTR-1 anti-cancer activity remains to be elucidated, and the effect on gastric cancer cells is unknown. Methods: Cell proliferation was determined by MTT and clone formation assay. The effect of RTR-1 on cell cycle distribution and apoptosis was analysed utilizing flow cytometry, respectively. Moreover, Western blotting was used to detect the expression of cell cycle-and apoptosis-related protein. Results: Based on MTT and clone formation assay, we noticed that RTR-1 inhibited the proliferation of gastric carcinoma (BGC823 and SGC7901) cells in a dose-and time-dependent manner. Furthermore, the results of flow cytometry and Western blotting showed that RTR-1 induced cell cycle arrest in the G2/M phase through the ATM-Chk2-p53-p21 signaling pathway and induced cell apoptosis by inhibiting the signal transducers and activators of transcription 3 (STAT3) pathway and activating the endoplasmic reticulum stress (ER stress) pathway. Conclusion: Taken together, these results demonstrate that RTR-1 induces cell cycle arrest and promotes apoptosis in gastric carcinoma, indicating its potential application for gastric cancer therapy.