The inhibitory effects of parthenolide （PTL） on angiogenesis induced by multiple myeloma （MM） cells in vitro and the mechanism were investigated. Human MM line RPMI8226 cells were cultured in vitro. The effects of...The inhibitory effects of parthenolide （PTL） on angiogenesis induced by multiple myeloma （MM） cells in vitro and the mechanism were investigated. Human MM line RPMI8226 cells were cultured in vitro. The effects of MM culture supernatant on the migration and tubule formation ability of human umbilical vein endothelial cells （HUVECs） treated with PTL were observed. By using Western blot, the expression of p65 and IкB-α in MM cells was detected. RT-PCR was used to assay the expression of VEGF, IL-6, MMP2 and MMP9 mRNA in MM cells. ELISA was used to measure the levels of VEGF and IL-6 in MM cell culture supernatant. The expression of MMP2 and MMP9 in MM cells was examined by immunohistochemistry. （1） In 3.5, 5.0, 7.5 and 10 μmol/L PTL groups the number of migrated cells was 310±56, 207±28, 127±21 and 49±10 respectively, which was significantly different from that in positive control group （598±47） （P〈0.01）. In 3.5 and 5.0 μmol/L PTL groups the areas of capillary-like structures were 0.092±0.003 and 0.063±0.002 mm2, significantly less than in positive control group （0.262±0.012 mm2） （P〈0.01）, but in 7.5 and 10 μmol/L PTL groups no capillary-like structures were found; （2） After treatment with different concentrations of PTL for 48 h, the expression of p65 protein was gradually decreased, while that of IкB-α was gradually enhanced with the increased concentration of PTL; （3） After treatment with 3.5, 5.0, 7.5 and 10 μmol/L PTL for 48 h, the VEGF levels in the supernatant were 2373.4±392.2, 1982.3±293.3, 1247.0±338.4 and 936.5±168.5 pg/mL respectively, significantly different from those in positive control group （2729±440.0 pg/mL） （P〈0.05）. After treatment with 7.5 and 10 μmol/L PTL, the IL-6 levels in the culture supernatant were 59.6±2.8 and 41.4±9.8 pg/mL respectively, signifi- cantly lower than in positive control group （1287.3±43.5 pg/mL） （P〈0.05）; （4） RT-PCR revealed that PTL could significantly inhibit the expression of VEGF and IL-6 mRNA in MM cells, but not influence the expression of MMP2 and MMP9 mRNA.; （5） Immunohistochemistry indicated that PTL had no significant effects on the expression of MMP2 and MMP9 protein in MM cells. It was concluded that the abilities of the culture supernatant of MM cells treated with PTL to induce endothelial cells migration and tubule formation were significantly reduced, suggesting PTL could obviously inhibit the angiogenesis induced by MM cells. PTL could decrease NF-kappaB activity and significantly suppress the expression of VEGF and IL-6 mRNA and protein, which might contribute to the mechanism by which PTL inhibited the angiogenesis induced by MM cells.展开更多
This study examined the mechanism of the inhibitory effect of parthenolide（PTL） on the activity of NF-κB in multiple myeloma（MM）. Human multiple myeloma cell line RPMI 8226 cells were treated with or without diff...This study examined the mechanism of the inhibitory effect of parthenolide（PTL） on the activity of NF-κB in multiple myeloma（MM）. Human multiple myeloma cell line RPMI 8226 cells were treated with or without different concentrations of PTL for various time periods, and then MTT assay was used to detect cell proliferation. Cell cycle and apoptosis were flow cytometrically detected. The level of protein ubiquitination was determined by using immunoprecipitation. Western blotting was employed to measure the level of total protein ubiquitination, the expression of IκB-α in cell plasma and the content of p65 in nucleus. The content of p65 in nucleus before and after PTL treatment was also examined with immunofluorescence. Exposure of RPMI 8226 cells to PTL attenuated the level of ubiquitinated Nemo, increased the expression of IκB-α and reduced the level of p65 in nucleus, finally leading to the decrease of the activity of NF-κB. PTL inhibited cell proliferation, induced apoptosis and blocked cell cycle. Furthermore, the levels of ubiquitinated tumor necrosis factor receptor-associated factor 6（TRAF6） and total proteins were decreased after PTL treatment. By using Autodock software package, we predicted that PTL could bind to TRAF6 directly and tightly. Taken together, our findings suggest that PTL inhibits the activation of NF-κB signaling pathway via directly binding with TRAF6, thereby suppressing MM cell proliferation and inducing apoptosis.展开更多
基金a grant from Hubei Natural Sciences Foundation of China (No. 2007ABA027)
文摘The inhibitory effects of parthenolide （PTL） on angiogenesis induced by multiple myeloma （MM） cells in vitro and the mechanism were investigated. Human MM line RPMI8226 cells were cultured in vitro. The effects of MM culture supernatant on the migration and tubule formation ability of human umbilical vein endothelial cells （HUVECs） treated with PTL were observed. By using Western blot, the expression of p65 and IкB-α in MM cells was detected. RT-PCR was used to assay the expression of VEGF, IL-6, MMP2 and MMP9 mRNA in MM cells. ELISA was used to measure the levels of VEGF and IL-6 in MM cell culture supernatant. The expression of MMP2 and MMP9 in MM cells was examined by immunohistochemistry. （1） In 3.5, 5.0, 7.5 and 10 μmol/L PTL groups the number of migrated cells was 310±56, 207±28, 127±21 and 49±10 respectively, which was significantly different from that in positive control group （598±47） （P〈0.01）. In 3.5 and 5.0 μmol/L PTL groups the areas of capillary-like structures were 0.092±0.003 and 0.063±0.002 mm2, significantly less than in positive control group （0.262±0.012 mm2） （P〈0.01）, but in 7.5 and 10 μmol/L PTL groups no capillary-like structures were found; （2） After treatment with different concentrations of PTL for 48 h, the expression of p65 protein was gradually decreased, while that of IкB-α was gradually enhanced with the increased concentration of PTL; （3） After treatment with 3.5, 5.0, 7.5 and 10 μmol/L PTL for 48 h, the VEGF levels in the supernatant were 2373.4±392.2, 1982.3±293.3, 1247.0±338.4 and 936.5±168.5 pg/mL respectively, significantly different from those in positive control group （2729±440.0 pg/mL） （P〈0.05）. After treatment with 7.5 and 10 μmol/L PTL, the IL-6 levels in the culture supernatant were 59.6±2.8 and 41.4±9.8 pg/mL respectively, signifi- cantly lower than in positive control group （1287.3±43.5 pg/mL） （P〈0.05）; （4） RT-PCR revealed that PTL could significantly inhibit the expression of VEGF and IL-6 mRNA in MM cells, but not influence the expression of MMP2 and MMP9 mRNA.; （5） Immunohistochemistry indicated that PTL had no significant effects on the expression of MMP2 and MMP9 protein in MM cells. It was concluded that the abilities of the culture supernatant of MM cells treated with PTL to induce endothelial cells migration and tubule formation were significantly reduced, suggesting PTL could obviously inhibit the angiogenesis induced by MM cells. PTL could decrease NF-kappaB activity and significantly suppress the expression of VEGF and IL-6 mRNA and protein, which might contribute to the mechanism by which PTL inhibited the angiogenesis induced by MM cells.
基金supported by the National Natural Science Foundation of China(No.81272624)
文摘This study examined the mechanism of the inhibitory effect of parthenolide（PTL） on the activity of NF-κB in multiple myeloma（MM）. Human multiple myeloma cell line RPMI 8226 cells were treated with or without different concentrations of PTL for various time periods, and then MTT assay was used to detect cell proliferation. Cell cycle and apoptosis were flow cytometrically detected. The level of protein ubiquitination was determined by using immunoprecipitation. Western blotting was employed to measure the level of total protein ubiquitination, the expression of IκB-α in cell plasma and the content of p65 in nucleus. The content of p65 in nucleus before and after PTL treatment was also examined with immunofluorescence. Exposure of RPMI 8226 cells to PTL attenuated the level of ubiquitinated Nemo, increased the expression of IκB-α and reduced the level of p65 in nucleus, finally leading to the decrease of the activity of NF-κB. PTL inhibited cell proliferation, induced apoptosis and blocked cell cycle. Furthermore, the levels of ubiquitinated tumor necrosis factor receptor-associated factor 6（TRAF6） and total proteins were decreased after PTL treatment. By using Autodock software package, we predicted that PTL could bind to TRAF6 directly and tightly. Taken together, our findings suggest that PTL inhibits the activation of NF-κB signaling pathway via directly binding with TRAF6, thereby suppressing MM cell proliferation and inducing apoptosis.
