RESUMEN
BACKGROUND: Curdione is a sesquiterpene isolated from Curcumae Rhizoma that possesses high biological activity and extensive pharmacological effects. As a traditional Chinese medicine, Curcumae Rhizoma can inhibit the development of many types of cancer, especially colorectal cancer. However, the anti-colorectal mechanism of its monomer curdione remains unclear. METHODS: Colorectal cancer (CRC) cells were treated with curdione at doses of 12.5 µM, 25 µM, and 50 µM, and then the cells' activity was measured with methyl thiazolyl tetrazolium (MTT). Nude mice were administered different doses of curdione subcutaneously and oxaliplatin by tail vein injection, and then hematoxylin-eosin (HE) staining was adopted to examine tumor histology. Moreover, flow cytometry was applied to detect reactive oxygen species in cells and tissues. Kits were employed to detect the levels of iron ions, malondialdehyde, lipid hydroperoxide, and glutathione. Polymerase chain reaction (PCR) and Western blotting were adopted to detect ferroptosis and m6A modification-related factors. A methylation spot hybridization assay was performed to measure changes in overall methylation. SLC7A11 and HOXA13 were measured by MeRIP-qPCR. The shRNA-METTL14 plasmid was constructed to verify the inhibitory effect of curdione on CRC. RESULTS: A dose-dependent decrease in activity was observed in curdione-treated cells. Curdione increased the accumulation of reactive oxygen species in CRC cells and tumor tissues, greatly enhanced the levels of malondialdehyde, lipid hydroperoxide and Fe2+, and lowered the activity of glutathione. According to the qPCR and Western blot results, curdione promoted the expression of METTL14 and YTHDF2 in CRC cells and tissues, respectively, and decreased the expression of SLC7A11, SLC3A2, HOXA13, and glutathione peroxidase 4. Additionally, in animal experiments, the curdione-treated group showed severe necrosis of tumor cells, as displayed by HE staining. Furthermore, compared with the control group, levels of m6A modifying factors (namely, SLC7A11 and HOXA13) were increased in the tissues after drug intervention. METTL14 knockdown was followed by an increase in CRC cell activity and glutathione levels. However, the levels of reactive oxygen species, malondialdehyde, and iron ions decreased. The expression levels of SLC7A11, SLC3A2, HOXA13, and GPX4 were all increased after METTL14 knockdown. CONCLUSION: The results suggest that curdione induces ferroptosis in CRC by virtue of m6A methylation.
RESUMEN
This study aims to investigate the effect of Astragali Radix-Curcumae Rhizoma(AC) combination on the proliferation, migration, and invasion of colon cancer HT-29 cells based on epithelial-mesenchymal transition(EMT). HT-29 cells were respectively treated with 0, 3, 6 and 12 g·kg~(-1) AC-containing serum for 48 h. The survival and growth of cells were measured by thiazole blue(MTT) colorimetry, and the proliferation, migration, and invasion of cells were detected by 5-ethynyl-2'-deoxyuridine(EdU) test and Transwell assay. Cell apoptosis was examined by flow cytometry. The BALB/c nude mouse model of subcutaneous colon cancer xenograft was established, and then model mice were classified into blank control group, 6 g·kg~(-1) AC group, and 12 g·kg~(-1) AC group. The tumor weight and volume of mice were recorded, and the histopathological morphology of the tumor was observed based on hematoxylin-eosin(HE) staining. The expression of apoptosis-associated proteins B-cell lymphoma-2-associated X protein(Bax), cysteine-aspartic acid protease-3(caspase-3), and cleaved caspase-3, and EMT-associated proteins E-cadherin, MMP9, MMP2 and vimentin in HT-29 cells and mouse tumor tissues after the treatment of AC was determined by Western blot. The results showed that cell survival rate and the number of cells at proliferation stage decreased compared with those in the blank control group. The number of migrating and invading cells reduced and the number of apoptotic cells increased in the administration groups compared with those in the blank control group. As for the in vivo experiment, compared with the blank control group, the administration groups had small tumors with low mass and shrinkage of cells and karyopycnosis in the tumor tissue, indicating that the AC combination may improve EMT. In addition, the expression of Bcl2 and E-cadherin increased and the expression of Bax, caspase-3, cleaved caspase-3, MMP9, MMP2, and vimentin decreased in HT-29 cells and tumor tissues in each administration group. In summary, the AC combination can significantly inhibit the proliferation, invasion, migration, and EMT of HT-29 cells in vivo and in vitro and promote the apoptosis of colon cancer cells.