Effect of Doxycycline on Intrinsic Apoptosis of Myeloma Cell Line H929 and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To investigate the mechanism of the in vitro toxicity of doxycycline to myeloma cell line H929 and also the possible pathway involved its toxicity.@*METHODS@#Myeloma cell line H929 was treated with DOX, MEK inhibitor U0126 or RAS agonist ML-098, either alone or in combination. Then, the expression of p-MEK, caspase-3, caspase-9 and c-Jun in H929 were used to detected by Western blot; the cells proliferation and apoptosis were detected by CCK-8 assay and flow cytometry, respectively.@*RESULTS@#DOX significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK in H929 (P<0.05). MEK antagonist U0126 significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK (P<0.05). After Dox combined with ML-098 treatment of H929 cells, the apoptosis rate of H929 cells was lower than that of DOX alone treatment group(P<0.05). Compared with DOX alone treatment group, the expressions of p-MEK and p-ERK1/2 in DOX+ML-098 combined treatment group were increased, and the levels of cleaved caspase-3,9 in H929 cells were decreased (P<0.05). The levels of c-Jun mRNA and protein increased in H929 when treated by DOX alone (P<0.05).@*CONCLUSION@#DOX can induce apoptosis of H929 via intrinsic apoptosis pathway, and MEK/ERK pathway and c-Jun possibly play a role in this process.

Effect of Celastrol Based on IRAK4/ERK/p38 Signaling Pathway on Proliferation and Apoptosis of Multiple Myeloma Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of celastrol on the proliferation and apoptosis of human multiple myeloma (MM) cell lines, reveal the relationship between IRAK4/ERK/p38 signaling pathway and celastrol regulating the proliferation and apoptosis of H929 and ARP-1 cells, and explore whether celastrol combined with bortezomib has synergistic effect. @*METHODS@#CCK-8 method was used to detect the viability of MM cell lines H929 and ARP-1 treated by different concentrations of celastrol, bortezomib, and their combination, and the synergistic effect was determined by Kim's formula. The apoptosis rate of H929 cells and necrosis rate of ARP-1 were detected by Annexin V/PI method. The expression of key proteins and apoptosis proteins in IRAK4/ERK/p38 signaling pathway were detected by Western blot. @*RESULTS@#Celastrol could significantly inhibit the proliferation of H929 and ARP-1 cells (r=0.9018, r=0.9244) and induce apoptosis in a time-dependent manner. Compared with the control group, celastrol could significantly up-regulate the expression of PARP and cleaved caspase-3 while down-regulate the expression of p-IRAK4, p-ERK, and p-p38 in H929 and ARP-1 cells. Celastrol and bortezomib alone inhibited the proliferation of H929 and ARP-1 cells. Compared with celastrol and bortezomib alone, their combination had lower cell survival rate and higher apoptosis rate (P<0.05). @*CONCLUSION@#Celastrol can inhibit the proliferation and promote the apoptosis of H929 and ARP-1 cells, which may be related to inhibiting the phosphorylation of IRAK4 and blocking the activation of IRAK4/ERK/p38 signaling pathway. Celastrol combined with bortezomib has synergistic effect, which can more effectively inhibit the proliferation and induce apoptosis of H929 and ARP-1 cells.

Inhibitory effects of curcumin on human multiple myeloma cell lines and their mechanisms / 肿瘤

Objective: This study was designed to explore the effects of curcumin on the proliferation and apoptosis of human multiple myeloma cell lines H929 and RPMI8226, and to investigate their relevant mechanisms. Methods: MTT assay was used to detect the inhibitory effect of curcumin on cell proliferation. Flow cytometry (FCM) was applied to study cell cycle distribution and apoptosis rate changes. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of survivin, Bcl-2, and Bax. Results: Curcumin inhibited the proliferation of myeloma cells H929 and RPMI8226 in a time- and concentration-dependent manner. Curcumin induced apoptosis of RPMI8226 and arrested RPMI8226 cells at G2/M phase. Curcumin significantly down-regulated mRNA expression of survivin and Bcl-2 in both H929 and RPMI8226 cells, while markedly up-regulated Bax mRNA expression. Conclusion: Curcumin inhibites the proliferation and induces the apoptosis of human multiple myeloma cells. This work supposes that the effect of curcumin on transcriptions of survivin, Bcl-2 and Bax might be one of the mechanisms underlying tumor inhibitory effects of curcumin.