Aim: To investigate curcumin (diferuloylmethane) induced apoptosis and its molecular mechanism of action in B-NHL cell line Raji cells. Methods: Raji cells were cultured in RPMI-1640 medium and treated with curcumin in different concentrations. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay was used to detect growth inhibition and Hoechst 33258 staining was used to detect apoptosis. Immunocytochemistry and Western blot were used to detect the expressions of histone deacetylase 1, 3, and 8 (HDAC1, HDAC3, and HDAC8) and acetylated histone H4 (Ac-histone H4) protein. Results: Curcumin inhibited the proliferation of B-NHL cell line Raji cells with a 36-h IC 50 value of 24.1±2.0 µmol/L. Hoechst 33258 staining showed that curcumin could induce Raji cell apoptosis. The expression levels of HDAC1, HDAC3, and HDAC8 proteins were downregulated following curcumin treatment in Raji cells, whereas Ac-histone H4 protein expression was upregulated after treatment with curcumin. Conclusion: Curcumin, as a new member of the histone deacetylase inhibitors, can inhibit the expression of class I HDACs (HDAC1, HDAC3, and HDAC8), and can increase the expression of Ac-histone H4 in Raji cells. Curcumin plays an important role in regulating B-NHL cell line Raji cell proliferation and apoptosis.
Background Myeloid-derived suppressor cells (MDSCs) and cancer stem cells (CSCs) are two important cellular components in the tumor microenvironment, which may modify the cancer phenotype and affect patient survival. However, the crosstalk between MDSCs and multiple myeloma stem cells (MMSCs) are relatively poorly understood. Methods The frequencies of granulocytic-MDSCs (G-MDSCs) in MM patients were detected by flow cytometry and their association with the disease stage and patient survival were analyzed. RT-PCR, flow cytometry, western blot and sphere formation assays were performed to investigate the effects of G-MDSCs, piRNA-823 and DNA methylation on the maintenance of stemness in MM. Then a subcutaneous tumor mouse model was constructed to analyze tumor growth and angiogenesis after G-MDSCs induction and/or piRNA-823 knockdown in MM cells. Results Our clinical dataset validated the association between high G-MDSCs levels and poor overall survival in MM patients. In addition, for the first time we showed that G-MDSCs enhanced the side population, sphere formation and expression of CSCs core genes in MM cells. Moreover, the mechanism study showed that G-MDSCs triggered piRNA-823 expression, which then promoted DNA methylation and increased the tumorigenic potential of MM cells. Furthermore, silencing of piRNA-823 in MM cells reduced the stemness of MMSCs maintained by G-MDSCs, resulting in decreased tumor burden and angiogenesis in vivo. Conclusion Altogether, these data established a cellular, molecular, and clinical network among G-MDSCs, piRNA-823, DNA methylation and CSCs core genes, suggesting a new anti-cancer strategy targeting both G-MDSCs and CSCs in MM microenvironment.
Aim: To explore the mechanisms underlying the oridonin-induced apoptosis and autophagy in human multiple myeloma cells in vitro. Methods: Human multiple myeloma RPMI8266 cells were used. The cell viability was assessed using MTT assay. Morphological changes of apoptosis and autophagy were observed under transmission electron microscope. TUNEL and annexin V-FITC/PI dual staining assays were used to measure apoptosis. Autophagy was analyzed using Western blot analysis and immunofluorescence staining with a QDs 605 nm -Anti-LC3 fluorescent probe. Intracellular ROS was estimated with flow cytometry using DCFH-DA fluorescent probe. Protein levels of active caspase 3, Beclin 1 and SIRT1 were determined with Western blot analysis. Results: Exposure to oridonin (1-64 µmol/L) inhibited the proliferation of RPMI8266 cells in a concentration-dependent manner with an IC 50 value of 6.74 µmol/L. Exposure to oridonin (7 µmol/L) simultaneously induced caspase 3-mediated apoptosis and Beclin 1-dependent autophagy of RPMI8266 cells. Both the apoptosis and autophagy were time-dependent, and apoptosis was the main effector pathway of cell death. Exposure to oridonin (7 µmol/L) increased intracellular ROS and reduced SIRT1 nuclear protein in a time-dependent manner. The blockade of intracellular generation of ROS by NAC (5 mmol/L) abrogated apoptosis, autophagy and the decrease of SIRT1 in the cells exposed to oridonin (7 µmol/L). The inhibition of autophagy by 3-MA (5 mmol/L) sensitized the cells to oridonin-induced apoptosis, which was accompanied by increased intracellular ROS and decreased SIRT1. Conclusion: Oridonin simultaneously induces apoptosis and autophagy of human multiple myeloma RPMI8266 cells via regulation of intracellular ROS generation and SIRT1 nuclear protein. The cytotoxicity of oridonin is mainly mediated through the apoptotic pathway, whereas the autophagy protects the cells from apoptosis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.