The effect of apoptosis induced by IL-21 in SUDHL-4 cell line and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the apoptosis effect of diffuse large B-cell lymphoma cell line (DLBCL) SUDHL-4 induced by IL-21 and its related mechanism.</p><p><b>METHODS</b>SUDHL-4 cells were treated with IL-21 at different concentration (1000 ng/ml, 100 ng/ml, 10 ng/ml, 1 ng/ml) for 24 h, 48 h, 72 h, respectively. The inhibitory rate of cell proliferation was detected by CCK-8 assay. The cell growth curves were drawn and half inhibitory concentration (IC(50)) values were calculated. The cell apoptosis were detected by flow cytometry (FCM), the expression of the caspase-9, caspase-3, cleaved caspase-3, Bcl-2, Bcl-XL, Bid, Bax and c-myc protein in SUDHL-4 cells treated with IL-21 by western blot, the mRNA expression of Bcl-2, Bcl-XL, Bid, Bax, c-myc by Survivin gene with RT-PCR.</p><p><b>RESULTS</b>IL-21 markedly inhibited SUDHL-4 cell growth in a time- and dose-dependent manner. The 48 hIC(50) was 140.9ng/ml; The FCM showed that the apoptosis proportion of SUDHL-4 cells treated with 100 ng/ml of IL-21 apoptosis (AnnexinV-FITC(+) positive cells) gradually increased (48 h: 19.7 ± 2.3%). The protein expression of caspase-9, caspase-3, Bcl-2 and Bcl-XL decreased in a time-dependent manner. The Bax and c-myc protein markedly increased, but the Bid protein level did not change. IL-21 up regulated c-myc and Bax gene expression, however down regulated Bcl-2 and BCL-XL gene expression, but the gene expression of Bid and Survivin hadn't been changed significantly.</p><p><b>CONCLUSIONS</b>IL-21 can inhibit proliferation and induce apoptosis of SUDHL-4 cell. The mechanism may involve in endogenous mitochondrial pathway mediated by the c-myc and the Bcl-2 genes.</p>

Silencing of survivin gene in Jeko-1 cell line with small interfering RNA / 中国实验血液学杂志

This study was aimed to investigate the impact of specific siRNA on survivin gene in transfected lymphoma cell line and provide experimental evidences for future treatment of mantle cell lymphoma. The small interfering RNA (siRNA) targeted survivin mRNA was synthesized in vitro and was transfected into Jeko-1 that showed high survivin expression in mRNA level. The levels of survivin mRNA and protein expression were detected by quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot respectively. The apoptosis effect was examined by calculating the ratio of Annexin V-FITC/PI positive cells using flow cytometry. The inhibition of cell proliferation was assayed with CCK-8 reagent after transfection. The results showed that expression of survivin mRNA was markedly suppressed by the siRNA. The relative expression levels were 0.49 ± 0.03, 0.38 ± 0.02 and 0.17 ± 0.02 at time points of 24, 48 and 72 h respectively, compared with the control group; the inhibitive rates of cell proliferation were (31.2 ± 2.1)%, (43.3 ± 3.4)% and (52.6 ± 2.5)%; the apoptotic rates of cells were (6.3 ± 0.5)%, (13.5 ± 1.1)% and (23.6 ± 1.6)% respectively; survivin protein expression levels were gradually reduced. It is concluded that the siRNA targeting survivin down-regulates the expressions of survivin mRNA and protein evidently. The siRNA of survivin displays the potent ability to inhibit the proliferation of lymphoma cell line Jeko-1; survivin may become a potential molecular target for the therapy of lymphoma in the future.

Study of hypermethylation of SOCS gene in typical myeloproliferative disease / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical role of hypermethylation of suppressor of cytokine signaling (SOCS) on typical myeloproliferative disease (MPD) patients and its mechanism.</p><p><b>METHODS</b>Methylation specific PCR was used to detect SOCS1, 2, 3 methylation, direct DNA sequencing was performed to detect JAK2V617F mutation, real-time fluorescence quantitative PCR were applied to evaluate transcriptional activity of SOCS1, 2, 3.</p><p><b>RESULTS</b>Among 100 MPD patients, hypermethylation of SOCS1 was detected in 27 (27%), hypermethylation of SOCS2 in 9 (9%), hypermethylation of SOCS3 in 34 (34%); JAK2V617F mutation in 64 (64%). Hypermethylation of SOCS1, 3 greatly inhibited gene expression compared with unmethylated ones (P < 0.05). Presence of JAK2V617F mutation markedly down-regulated SOCS1, 3 gene mRNA expression compared with wild JAK2V617F (P < 0.05).</p><p><b>CONCLUSION</b>Hypermethylation of SOCS1, 3 and JAK2V617F mutation exist in MPD, which inhibited SOCS1, 3 gene expression. SOCS hypermethylation and JAK2V617F mutation can activate JAK-STAT signaling pathways, these observations may provide a potential therapeutic direction.</p>

Effect of hypoxia on HIF-1α and its sumoylation in Jurkat cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of hypoxia on sumoylation of HIF-1α, as well as transcriptional activity and protein stability of HIF-1α in Jurkat cells, and explore its effect and significance on modulating the transcriptional activity of down stream target gene.</p><p><b>METHODS</b>CoCl(2) was used as a chemical inducer to simulate the hypoxia environment. Real-time fluorescence quantitative PCR and western blot were used to evaluate transcriptional activity and protein stability of HIF-1α, levels of SUMO-1 and SENP1 protein, and gene transcripts of VEGF, mdr1, mdr3, Mcl-1 and survivin respectively.</p><p><b>RESULTS</b>After 4 h, 8 h, 16 h, 24 h and 72 h after hypoxia induction, the gene transcripts of HIF-1α were 0.79 ± 0.19, 2.65 ± 2.05, 4.19 ± 4.72, 2.77 ± 3.37, 0.09 ± 0.05 and 0.69 ± 0.55-fold (P > 0.01) of that of 0h in Jurkat cells, respectively, while the protein stability increased first, then decreased (P < 0.01). SENP-1 protein up-regulated first, then down-regulated, and the SUMO-1 protein changed in an opposite trend. Excepting for survivin gene, transcriptional activities of VEGF, mdr1, mdr3, and Mcl-1 were affected by the stability of HIF-1α protein.</p><p><b>CONCLUSION</b>Hypoxia induces changes in SENP-1 expression, which increases the stability of HIF-1α by decreasing the sumoylation of HIF-1α and affects biological process by regulating the transcriptional activities of VEGF, mdr1, mdr3 and Mcl-1 gene.</p>

Effect of VEGFR1 gene silencing by shRNA on proliferation, migration and apoptosis of U937 line / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of lentivirus-mediated RNA interference targeting vascular endothelial growth factor receptor 1 (VEGFR1) gene on the proliferation, migration and apoptosis of leukemic cell line U937.</p><p><b>METHODS</b>Short hairpin RNAs (shRNA) targeting VEGFR-1 was synthesized and cloned into pRNAT-U6.2 lentiviral vector. The expression vectors were transfected into 293T cell line to produce packaged lentivirus. After infected with the packaged lentivirus, the expression of VEGFR-1 gene of U937 cells at mRNA and protein level was detected by real-time PCR and Western blot. VEGF production by the cells was determined by ELISA. Cell proliferation and survival under regular culture and in the presence of cytarabine (Ara-C) was determined by CCK-8 assay. Migration assays were performed by 5 µm pore transwell inserts.</p><p><b>RESULTS</b>The lentiviral shRNA vector targeting VEGFR-1 was successfully constructed and transfected into U937 cells. The shRNA vector effectively inhibited the expression of VEGFR-1 gene in U937 cell line at mRNA and protein levels. As compared to that of the control, the proliferation rate of U937-shVEGFR-1 cells reduced; The VEGF production and migrated cell number of U937-shVEGFR-1 cells decreased dramatically. After treated with Ara-C, the inhibition rate and apoptotic rate of U937-shVEGFR-1 cells increased significantly. The number of migrated cells in the KD group under regular culture and in the presence of VEGF was markedly lower than that in the NC group and CON group. Bevacizumab could decrease the number of migrated cells in the NC group and CON group, but could not in the KD group.</p><p><b>CONCLUSIONS</b>Lentivirus-mediated RNA interference targeting VEGFR1 gene reduces the proliferation, migration of U937 cell line and enhances its sensitivity to Ara-C.</p>