Rauwolfia vomitoria Extract Represses Colorectal Cancer Cell Autophagy and Promotes Apoptosis.

BACKGROUND: Colorectal cancer (CRC) is one of the most frequent digestive tract tumors in the world with an increasing incidence. Currently, surgical resection and chemotherapy are the main therapeutic options; however, their effects are limited by various adverse reactions. Rauwolfia vomitoria extract (Rau) has been shown to repress the progression of multiple human cancers; however, whether Rau plays a role in CRC remains undetermined. METHODS: Influences of Rau treatment on HCT-116 and LoVo cells were estimated via MTT and colony formation experiments. Flow cytometry analysis was adopted to evaluate the apoptosis rate of HCT-116 and LoVo cells. Apoptosis-related proteins (Bcl-2, Bax, and caspase-3) and autophagy-related proteins (LC3 and P62) were assessed by Western blotting. Effects of Rau on autophagy of HCT-116 and LoVo cell were evaluated through GFP-LC3 analysis. In vivo xenograft tumor assay was conducted to further examine the role of Rau in CRC tumor growth. RESULTS: Rau remarkably repressed HCT-116 and LoVo cell viability and promoted HCT-116 and LoVo cell apoptosis in vitro in a dose-dependent manner. Rau increased the expression of caspase-3 and Bax and decreased the expression of Bcl-2 in HCT-116 and LoVo cells. Moreover, Rau was demonstrated to decrease the LC3||/LC3| ratio and increase the level of P62 in HCT-116 and LoVo cells. In addition, we found that Rau repressed xenograft tumor growth and also repressed autophagy in vivo. CONCLUSION: Our findings revealed that Rau repressed CRC cell viability and autophagy in vitro and in vivo, suggesting that Rau might be a potent therapeutic agent of CRC.

Pectic polysaccharides ameliorate the pathology of ulcerative colitis in mice by reducing pyroptosis.

Background: Ulcerative colitis (UC) is an inflammatory bowel disease which seriously affects the quality of life of patients. There has been an increasing amount of research related to the therapeutic effects and mechanisms of natural plant substances in the treatment of recurrent UC. Rauwolfia verticillata var. Hainanensis is a medicinal plant that is native to Hainan Island, China. Some studies have documented that pectic polysaccharides (PPs) from Rauvolfia inhibited the progression of colon ulcers. However, their mechanisms of action have not been established. Studies have revealed that suppressing pyroptosis can attenuate the damage of experimental colitis. However, it is unclear whether PPs from Rauvolfia verticillata inhibit inflammation through pyroptosis. This study investigated the effects and potential mechanisms of PPs extracted from Rauvolfia verticillata on experimental UC in mice. Methods: Male C57 mice (6-8 weeks old) were allocated into the control group, the dextran sulfate sodium (DSS)-induced UC model group (DSS group), or the DSS with pectic polysaccharides treatment group (DSS + PP group). The body weights, rectal bleeding, and stool consistencies in the mice were observed, and the disease activity index (DAI) score was calculated. Colon tissues were collected for pathological analysis by histological hematoxylin and eosin (H&E) staining. The levels of caspase-1 and interleukin (IL)-1ß were detected by immunohistochemistry. Pyroptosis was assessed by transmission electron microscopy. Results: UC in mice induced by DSS resulted in decreased general physical activity and body weight, increased DAI score, significant histological changes, inhibited caspase-1 and IL-1ß expression, and promoted pyroptosis. These DSS-induced changes could be partially ameliorated by administration of PP. Conclusions: PPs exerted an ameliorative effect on DSS-induced UC in mice by reducing pyroptosis.

Mechanism of M2 macrophage-derived extracellular vesicles carrying lncRNA MEG3 in inflammatory responses in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. M2 macrophages possess certain anti-inflammation activity. Accordingly, the current study set out to investigate the potential mechanism of M2 macrophage-derived extracellular vesicles (M2-EVs) in UC inflammation. Firstly, mouse peritoneal macrophages were induced to M2 phenotype, and M2-EVs were isolated. , the murine model of UC was established, and the length and weight of the colon, disease activity index (DAI), apoptosis, and inflammatory response of UC mice were measured. Young adult mouse colon (YAMC) cells were induced with the help of lipopolysaccharide. LncRNA maternally expressed 3 (LncRNA MEG3), miR-20b-5p, and cAMP responsive element binding protein 1 (CREB1) expression patterns were detected in UC models. In addition, we analyzed the binding relationship among MEG3, miR-20b-5p, and CREB1. UC mice presented with shortened colon length, lightened weight, increased DAI score, enhanced apoptosis, and significant inflammatory cell infiltration, while M2-EVs reversed these trends. In vitro, M2-EVs increased UC cell viability and reduced inflammation. Mechanistic experimentation revealed that M2-EVs transferred MEG3 into YAMC cells to up-regulate MEG3 expression and promote CREB1 transcription by competitively binding to miR-20b-5p. Moreover, up-regulation of MEG3 in M2-EVs enhanced the protective effect of M2-EVs on UC cells, while over-expression of miR-20b-5p attenuated the aforementioned protective effect of M2-EVs on UC mice and cells. Collectively, our findings revealed that M2-EVs carrying MEG3 enhanced UC cell viability and reduced inflammatory responses via the miR-20b-5p/CREB1 axis, thus alleviating UC inflammation.