Effects of triptolide on RIZ1 expression, proliferation, and apoptosis in multiple myeloma U266 cells

Abstract

Aim: To investigate the effects of triptolide on proliferation and apoptosis as well as on the expression of RIZ1 in the human multiple myeloma cell line U266 in vitro. Methods: The effect of triptolide on the growth of U266 cells was studied by MTT assay. Apoptosis was detected by Hoechst 33258 staining and Annexin V/PI double-labeled flow cytometry, and caspase-3 mRNA was measured by RT-PCR. Western blotting, flow cytometry and RT-PCR were used to assess the expression of RIZ1, and the location and expression of H3K9me1 were detected by confocal microscopy and Western blotting. Results: Triptolide significantly inhibited the proliferation of U266 cells in a time-and concentration-dependent manner (the IC 50 value for a 24-h exposure was 157.19±0.38 nmol/L). Triptolide induced typical apoptotic morphological changes. Triptolide 40, 80, and 160 nmol/L treatment induced significant caspase-3-dependent apoptosis compared with control group (10.5%±1.23%, 37.9%±2.45%, and 40.5%±2.30% vs 3.8%±1.98%, P<0.05). Compared with peripheral blood monocular cells (PBMC) from healthy donors, the protein expression of RIZ1 in U266 cells was relatively low, but the mRNA and protein expression of RIZ1 were strikingly increased by triptolide in a concentration-dependent manner. Triptolide increased the protein expression of RIZ1 and RIZ1 methylates histone H3 lysine 9 in U266 cells. Conclusion: Triptolide increased the protein expression of RIZ1, inhibited the proliferation, and induced caspase-dependent apoptosis in U266 cells.

Triptolide induces cell-cycle arrest and apoptosis of human multiple myeloma cells in vitro via altering expression of histone demethylase LSD1 and JMJD2B

“…The rates of inhibition by 50, 100, and 150 nmol/L triptolide were 34.7%, 29.4%, and 39.6%, respectively; (P<0.05 vs untreated control) ( Figure 7B). We also found that the expression of trimethylated H3K9 decreased in RPMI8226 cells, and monomethylated H3K9 was elevated in U266 cells in a dose-dependent manner following treatment with increasing concentrations of triptolide [15,18] .…”

“…H3K36me2/me3 are enriched mostly in the transcribed region of active genes and are associated with the later stages of transcription in actively transcribed regions [18] . However, a direct association between H3K36me2 and proapoptotic genes has not been proven; further investigation will be required to clarify this relationship.…”

Hif-1α Overexpression Improves Transplanted Bone Mesenchymal Stem Cells Survival in Rat MCAO Stroke Model

“…Cells were resuspended in 200 μL Annexin-binding buffer containing 10 μL Annexin V-FITC and 5 μL PI. After 30 min of incubation in the dark, 300 μL phosphate buffer saline (PBS) were added into cells, and the apoptotic cells were distinguished under a flow cytometry (Beckman Coulter, CA, USA) immediately (Zhao et al, 2010). …”

LLDT-67 attenuates MPTP-induced neurotoxicity in mice by up-regulating NGF expression

“…Therefore, the search for novel drugs for the treatment of PD is an important endeavor. Triptolide is one of the major active components of the Chinese herb Tripterygium wilfordii Hook F. It is well known that triptolide has anti-inflammatory, immunosuppressive, contraceptive and antitumor properties [3][4][5] . Some studies indicate that PD is a chronic neuroinflammatory process, and triptolide has been found to possess antiparkinsonian effects [6] .…”