Utility of BMI-1 and NANOG expression levels in survival prediction of pediatric acute lymphoblastic leukemia

ABSTRACT Background Acute lymphoblastic leukemia (ALL) is the most common malignancy in children characterized by the overproduction and accumulation of immature lymphoid cells in the bone marrow and peripheral blood. The BMI-1 is an important component of the Polycomb Repressive Complex-1 (PRC1). It is an important molecule for the self-renewal of hematopoietic stem cells (HSCs). The BMI-1 expression is generally high in HSCs and decreases after cell differentiation. The BMI-1 is required for the maintenance of normal and cancer stem cells and has been reported as an oncogene in various tumors. The NANOG is a homeodomain transcription factor responsible for maintaining the stem cell compartment at the blastocyst stage of developing embryos. The NANOG gene has been proven to be transcribed in CD34+ cells and different leukemic cells. Methods The ribonucleic acid (RNA) was extracted from the peripheral blood mononuclear cells (PBMNCs) of 30 pediatric ALL patients (16 B-ALL and 14 T-ALL) and 14 healthy controls. The Bmi-1 and NANOG expression levels were determined using the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Results Compared to normal controls, patients with ALL exhibited upregulated levels of Bmi-1 (p = 0.03). Patients who overexpressed Bmi-1 and NANOG displayed a significantly worse survival than low-expressing patients (hazard ratio (HR) 5.74, 95% confidence interval (CI):1.48-22, p = 0.012 and HR 3.8, 95% CI:1.009-14.3, p = 0.048, respectively). Conclusions Taken together, these data suggest that the Bmi-1 and NANOG might serve as a novel survival predictor in ALL patients. Our observation also suggests that the Bmi-1 and NANOG could serve as new therapeutic targets for treatment of pediatric ALL.

Targeting BMI-1-mediated epithelial-mesenchymal transition to inhibit colorectal cancer liver metastasis

Liver is the most common metastatic site for colorectal cancer (CRC), there is no satisfied approach to treat CRC liver metastasis (CRCLM). Here, we investigated the role of a polycomb protein BMI-1 in CRCLM. Immunohistochemical analysis showed that BMI-1 expression in liver metastases was upregulated and associated with T4 stage, invasion depth and right-sided primary tumor. Knockdown

Effect of Bmi-1 on invasion and metastasis of renal cancer cells and its related mechanism / 中国药理学通报

: Aim To detect the effect of B-cell-specific moloney murine leukemia virus in section site 1 (Bmi-1) on the migration and invasion of renal cancer cell line 786-0 and ACHN and its possible mechanism. Methods siRNA interfered with the expression of Bmi-1 in renal cancer cells, and the effects of Bmi-1 on the migration and invasion of renal cancer cells were detected by scratch healing and Transwell chamber assay. The expression of invasion and metastasis related proteins in 786-0 and ACHN after Bmi-1 knockdown were detected by Western blot. Results Protein expression of Bmi-1 increased in renal cancer cells. In vitro synthesis of specific Bmi-1 gene siRNA significantly inhibited the expression of Bmi-1 in 786-0 and ACHN cells. After silencing Bmi-1, the scratch healing ability and migration and invasion activity of renal cancer cells were significantly lower than those of control cells. The results of Western blot showed that epithelial markers E-cadherin increased after Bmi-1 silencing, while the expression of Vimentin decreased, and the phosphorylation level of Akt was also reduced. Conclusions Silencing Bmi-1 inhibits the migration and invasion of renal cancer cells, and its effect is related to the activation of Akt signaling pathway.

ABCB1 and BMI1 mRNA expression in patients with chronic myeloid leukemia: impact on imatinib efficacy

BACKGROUND: ATP-binding cassette transporters are important in the mechanism of multidrug resistance. ABCB1 displays a high affinity for imatinib. BMI1 is a polycomb group protein thought to be overexpressed in leukemic cells. METHODS: This study was conducted to investigate the prognostic value of ABCB1 and BMI1 expressions in chronic myeloid leukemia (CML). Expression levels were measured in 81 patients newly diagnosed with CML and 20 healthy controls by real time reverse transcription- PCR. RESULTS: The ABCB1 expression levels did not differ between patients with CML and controls. Low ABCB1 mRNA levels were observed in patients who achieved an optimal response compared to suboptimal and resistant cases (P=0.005). Non-responders showed the highest ABCB1 levels. ABCB1 expression did not affect the progression-free survival (PFS) of patients. BMI1 expression was higher in patients than that in controls (P=0.001). Patients in advanced phases expressed higher levels of BMI1 than those in the chronic phase (P=0.004). High BMI1 expression was associated with a shorter PFS. CONCLUSION: ABCB1 mRNA expression may serve as a predictor of the optimal response to imatinib treatment in patients with CML. BMI1 expression was higher in the accelerated and blastic crisis phases of CML and associated with a shorter PFS.

Effects of Bmi1 on proliferation of cranial suture mesenchymal cells in mice / 中华整形外科杂志

Objective@#To explore the effects of Bmi1 on proliferation of mouse cranial suture mesenchymal cells.@*Methods@#Primary posterior frontal and sagittal suture derived cells were isolated from the 2-5 d old C57BL/6 suckling mice (n=6) of the same brood and cultured. Flow cytometry and multilineage differentiation assay were performed to identify the mesenchymal stem cells (MSCs) characteristics of the 2 kinds of cranial suture-derived cells. The mRNA expression of stem cell related genes, Bmi1, Twist1, Gli1 and Axin2 were detected by real-time quantitative polymerase chain reaction (RT-PCR). Then, the proliferation and downstream protein expression were analyzed after down-regulation of Bmi1 in the sagittal suture derived MSCs by transfecting Bmi1 siRNA. The t test was used to compare the mean between two groups. Statistical significance was set at P<0.05.@*Results@#The mouse cranial suture derived cells were successfully cultured in vitro. These cells expressed typical MSCs markers, CD44, CD90, CD73, except for CD34. These cells had osteogenic, adipogenic and chondrogenic differentiation potency. RT-PCR results showed that the mRNA expressions of Bmi1 (0.006 30±0.000 58 vs 0.002 60±0.000 34, t=5.430, P=0.005 6), Twist1(0.000 31±0.000 04 vs 0.000 15±0.000 02, t=3.343, P=0.028 8), Axin2(0.000 33±0.000 03 vs 0.000 17±0.000 05, t=3.067, P=0.037 4) and Gli1 (0.001 10±0.000 13 vs 0.000 60±0.000 33, t=3.956, P=0.016 7) were significantly decreased in the posterior frontal suture MSCs compared with those in sagittal suture derived cells. Among them, Bmi1 has the largest decline. After down-regulation of Bmi1 in sagittal suture MSCs, the protein expression level of Ink4a was significantly up-regulated compared with the control group, and the cell proliferation ability was significantly decreased.@*Conclusions@#Inhibition of Bmi1 expression can up-regulate the expression of Ink4a protein and decrease the proliferation ability of suture MSCs, which may lead to craniosynostosis.

Regulatory effects of Bmi-1 and MDR1 on the chemosensitivity of human non-small cell lung cancer cells to cisplatin / 医学研究生学报

Objective The purpose of this study was to investigate the mechanism of Bmi-1 regulating the sensitivity of non-small cell lung cancer (NSCLC) to chemotherapy by observing its effects on multidrug-resistance protein 1 (MDR1) and apoptosis-related proteins. Methods Small interfering RNAs (siRNA) targeting Bmi-1 were transfected into A549 and A549/DDP cells of NSCLC and the logarithmic-phase cells were randomly divided into a siRNA-Bmi-1, a siRNA-negative control and a blank control group. The A549 cells were treated with siRNA-Bmi-1, DDP or Bmi-1+DDP, or left untreated (the control). CCK8 assay was employed to measure the 50% inhibitory concentration (IC50) of cisplatin in the A549 and A549/DDP cells before and after treatment. The apoptosis of the cells was detected by flow cytometry, the mRNA expression of Bmi-1 determined by RT-PCR, and the relationship of Bmi-1 with MDR1 and cleaved caspase-3 proteins analyzed by Western blot. Results After transfection, the relative mRNA and protein expressions of Bmi-1 in the A549 and A549/DDP cells were significantly lower in the siRNA-Bmi-1 than in the blank control group (P < 0.05), but higher in the A549/DDP than in the A549 cells. The survival rates of the A549 and A549/DDP cells were decreased with the increased concentration of cisplatin (P < 0.05), even lower in the Bmi-1+DDP than in the DDP subgroup (P < 0.05). The apoptosis rate of the A549 cells was markedly higher in the Bmi-1+DDP than in the DDP, Bmi-1 and control groups ([39.65±3.41]% vs [23.11±1. 62] %, [2.05±1.56]% and [1.98±1.05]%, P < 0.05). After 24 hours of treatment with DDP, both the expressions of Bmi-1 and MDR1 were remarkably elevated, while the down-regulation of Bmi-1 significantly decreased the expression of MDR1 and increased that of cleaved caspase-3. Conclusion The expression of siRNA-Bmi-1 makes non-small lung cancer cells more sensitive to cisplatin, which might be associated with its inhibition of MDR1 expression and activation of apoptosis-related proteins.

Knockdown of long non-coding RNA ANRIL inhibits tumorigenesis in human gastric cancer cells via microRNA-99a-mediated down-regulation of BMI1

Long non-coding RNA antisense non-coding RNA in the INK4 locus (ANRIL) has been reported to promote tumorigenesis via regulating microRNA (miR)-99a in gastric cancer cells. However, the role of each component involved in it is still not well understood. This study aimed to verify the role of ANRIL in gastric cancer as well as the underlying mechanisms. ANRIL levels in clinical gastric cancer tissues and cell lines were tested by qPCR. Effects of ANRIL silence on cell viability, migration and invasion, apoptosis, and miR-99a expression in MKN-45 and SGC-7901 cells were measured using CCK-8, Transwell assay, flow cytometry, and qPCR assays, respectively. Then, effects of miR-99a inhibition on ANRIL-silenced cells were evaluated. B-lymphoma Mo-MLV insertion region 1 (BMI1) expression, after abnormal expression of ANRIL and miR-99a, was determined. Finally, expression of key proteins in the apoptotic, Notch, and mTOR pathways was assessed. ANRIL level was elevated in gastric cancer tissues and cell lines. Knockdown of ANRIL suppressed cell viability, migration, and invasion, and increased apoptosis through up-regulating miR-99a. Furthermore, ANRIL silence down-regulated BMI1 via up-regulating miR-99a. BMI1 silence down-regulated Bcl-2 and key kinases in the Notch and mTOR pathways and up-regulated p16 and cleaved caspases. We verified the tumor suppressive effects of ANRIL knockdown in gastric cancer cells via crosstalk with miR-99a. Together, we provided a novel regulatory mechanism for ANRIL in gastric cancer, in which ANRIL silence down-regulated BMI1 via miR-99a, along with activation of the apoptotic pathway and inhibition of the Notch and mTOR pathways.

The expression and correlation of BMI1 gene in gastrointestinal stromal tumor / 医学研究生学报

Objective The role of BMI1 gene in the development of gastrointestinal stromal tumor (GIST) has not yet been clarified. This study aimed to explore the expression of BMI1 gene in gastrointestinal stromal tumor,and analyze its relationship with clinical pathological features of GIST. Methods The clinical data of 68 GIST patients treated in The First People's Hospital of Nan-ning from August 2012 to October 2015 were analyzed retrospectively. The expression of BMI1 in normal gastrointestinal tissues and GIST tissues were detected with immunohistochemistry method,and analyzed the relationship between various clinicopathological pa-rameters of GIST and BMI1. The expression of BMI1 protein was detected by Western blot. Results The positive rate of BMI1 was much higher in GIST group than in non-GIST (76.47% vs 36.84%,P<0.05). The difference in the expression of BMI1 protein between the different risk groups was statistically significant (P<0.05). The positive expression rate was the highest in the high-risk group (93.75%),but had no statistically significant difference among different genders,age,locations,histological types and whether me-tastasis (P>0.05). Expression of proliferation genes such as PCNA,CyclinD1 mRNA in BMI1 positive group were higher than those in BMI1 negative group,the expression of Pro-apoptotic genes such as Caspase-7,Smac mRNA were lower than those in BMI1 negative group,the expression of anti-apoptosis genes such as Livin,p53,Bcl-2 mRNA were higher than those in BMI1 negative group (P<0.05). Conclusion The expression of BMI1 protein was increased in GIST tissue. It is correlated with the risk classification,and is an important factor affecting the prognosis of patients.

Analysis of the Epithelium-Mesenchymal Transition Process on Oral Squamous Cell Carcinomas

Abstract The aim of this study is to evaluate the immunohistochemical expression of E-cadherin, N-cadherin and Bmi-1, and their association with clinical parameters and with the degree of histopathological differentiation in oral squamous cell carcinomas. 65 squamous cell carcinoma samples were used for constructing a tissue microarray block, and then immunohistochemistry was performed for different markers. A semi-quantitative analysis of the amount of positive tumor cells was performed by two blind and calibrated observers (Kappa>0.75). The statistical Mann-Whitney and Kruskal-Wallis tests were used to evaluate the data. The correlation between variables was investigated by the Spearman test, and the significance level set at p<0.05. We observed higher expression of Bmi-1 in tumors located in the palate (p<0.0001). In addition, poorly differentiated tumors had a greater amount of Bmi-1 positive cells (p=0.0011). Regarding the other correlations between variables, no significant associations were detected. In conclusion, poorly differentiated squamous cell carcinomas located in the palate have higher immunostaining of Bmi-1, which can characterize activation of the Epithelial-Mesenchymal Transition process in these tumors.

Resumo O objetivo deste estudo foi avaliar a associação entre a expressão imunoistoquímica de E-caderina, N-caderina e Bmi-1, com os parâmetros clínicos e o grau de diferenciação em carcinomas espinocelulares bucais. Sessenta e cinco amostras foram selecionadas para a construção de um bloco de microarranjo tecidual, e a técnica de imunoistoquímica foi realizada para os diferentes marcadores. Uma análise semi-quantitativa das células tumorais positivas foi realizada por dois observadores calibrados e cegos (Kappa>0.75). Os testes estatísticos Mann-Whitney e Kruskal-Wallis foram utilizados para a análise dos dados e a correlação entre as variáveis foi investigada com o teste de Spearman. O nível de significância foi determinado em p <0.05. Observamos maior expressão de Bmi-1 em tumores localizados em palato (p <0.0001). Além disso, tumores pobremente diferenciados apresentaram maior quantidade de células positivas para Bmi-1 (p=0.0011). Não encontramos outras correlações ou associações significativas. Em conclusão, carcinomas espinocelulares pobremente diferenciados e localizados no palato apresentam maior marcação imunoistoquímica de Bmi-1, o que pode caracterizar a ativação do processo de transição epitélio-mesênquima nesses tumores.

Expression of BMI-1 in gastric cancer and its clinical significance / 肿瘤研究与临床

Objective To detect the expression of BMI-1, and to discuss its role in the development of gastric cancer. Methods The expression of BMI-1 protein and mRNA in gastric cancer and adjacent tissues was detected by immunohistochemical P-V method (78 cases) and semi-quantitative RT-PCR (30 cases). Results The positive expression rate of BMI-1 protein in gastric cancer patients was 66.7 % (52/78), and it was 19.2 % (15/78) in adjacent tissues, the difference was statistically significant (χ2= 35.815, P= 0.000). The expression of BMI-1 mRNA in 30 gastric cancer tissues was 0.23 ± 0.12, it was 0.03 ± 0.12 in adjacent tissues, the difference was statistically significant (t=8.372, P=0.000). The expression of BMI-1 protein and mRNA was correlated with the degree of tumor differentiation, depth of invasion, lymph node metastasis and TNM staging (all P< 0.05). Conclusion The expression of BMI-1 is closely related to the occurrence and development of gastric cancer, which may provide guidance for molecular pathogenesis, targeted therapy and prognosis of gastric cancer.

Effect of BMI-1 on radiosensitization of esophageal carcino-ma cells after silencing of BMI-1 gene / 中华放射肿瘤学杂志

Objective To investigate the effects of BMI-1 expression inhibition by RNA interference on the radiosensitivity of esophageal cancer TE-13 cells and its mechanism.Methods The siRNA based on the sequence of BMI-1 mRNA was synthesized to transfect cultured TE-13 cells as BMI-1 siRNA group,a negative one was synthesized to transfect cultured TE-13 cells as negative control group (NC group),and untransfected TE-13 cells were named as control group.The expression of the BMI-1 mRNA and protein in TE-13 cells was measured by quantitative real-time PCR and Western blot,respectively.The cell proliferation and the radiosensitivity of TE-13 cells were measured by MTS and colony-forming assay,respectively.Flow cytometry was used to analyze cell cycle and apoptosis.The expression of BCL-2 and BAX in TE-13 cells was measured by Western blot.Comparison between groups was made by analysis of variance.Results The BMI-1 siRNA group had significantly lower expression of BMI-1 mRNA and protein than the control group and the NC group (P=0.000,0.000).The proliferation of TE-13 cells in the BMI-1 siRNA group decreased significantly after irradiation (P=0.031).The colony-forming assay showed that the BMI-1 siRNA group had a significantly higher radiosensitivity than the control group and the NC group (P=0.000).After irradiation,the BMI-1 siRNA group had a significantly lower percentage of cells in G2/M phase than the control group and the NC group (P=0.000,0.000).The BMI-1 siRNA group had a significantly increased apoptosis rate (P=0.000,0.000),significantly reduced expression of BCL-2(P=0.000,0.000),and significantly increased expression of BAX after irradiation (P=0.000,0.000).Conclusions BMI-1 siRNA can inhibit the expression of BMI-1 gene in esophageal cancer TE-13 cells,eliminate the cell cycle arrest in G2/M phase,induce cell apoptosis after ionizing irradiation in vitro,and increase the radiosensitivity,which may be related to the regulation of the expression of BCL-2 and BAX.

Bmi-1 expression of bone marrow mesenchymal stem cells induced by fluid shear stress mediated with Akt signal molecule / 医用生物力学

Objective To investigate the effect of fluid shear stress (FSS) on the expression of B lymphoma Mo-MLV insertion region 1 (Bmi-1) in bone mesenchymal stem cells (BMSCs) and possible signal transduction mechanism. Methods BMSCs were isolated from SD rats and FSS at different magnitude (0.5, 1.5, 3.0 Pa) and under different time phase (1, 2, 6, 24 h) were loaded by parallel-plate flow chamber system. The expression of Bmi-1 was measured by real-time RT-PCR at mRNA level and the levels of phosphorylated Akt (p-Akt) and extracellular signalregulated kinase 1/2 (p-ERK1/2) were detected by Western blotting. The signaling inhibitors, wortmannin (PI3K specific inhabitor) and PD98059 (ERK1/2 specific inhabitor), were used to investigate possible mechanical signal transduction pathway. Results Bmi-1mRNA expression increased when BMSCs were exposed to 1.5 Pa FSS for 1 h and reached the peak at 24 h. All FSS with different magnitude could increase Bmi-1 expression, especial at high FSS (3.0 Pa). Meanwhile, FSS resulted in a significant activation of p-Akt and p-ERK1/2 in BMSCs. After treated with wortmannin, the expression of Bmi-1 was inhibited prominently, however, PD98059, the expression of Bmi-1 did not change. Conclusions FSS can activate the expression of Bmi-1, the amount of Bmi-1 expression was closely related to the stimulating time and the magnitude of FSS, and Akt signal molecule plays an important role during the process. These findings provide significant references for studying the mechanical biological mechanisms of stem cell differentiation.

Progress on the cell-surface markers and signaling pathways of colorectal cancer stem cells / 基础医学与临床

Colorectal stem cells have many bio-markers, including Lgr5 which expression is associated with THE stage of disease , also regulating the cell cycle , anothers is +4 stem cell , which is associated with tumor heteroge-neity, also expressed Bmi1, arresting cell cycle.Besides there is Msi1.Many studies show that those markers are highly expressed in colorectal cancer , which activate Notch and Wnt signaling pathway , and can promote the pro-gress of tumor .

Effect of RNAi targetingBMI-1 gene on radiosensitivity of esophageal carcinoma cells / 中国癌症杂志

Background and purpose:B cell-specific MLV integration site 1 (BMI-1) gene plays an important role in DNA damage after exposure to irradiation. The present study aimed to investigate the effect ofBMI-1 on radio-sensitivity of esophageal carcinoma cell after down-regulation of BMI-1 expression by silencing siRNA.Methods:Three pairs of siRNA based on the sequences of the BMI-1 mRNA were synthesized (siRNA1, siRNA2 and siRNA3) by compa-ny, and transfected into cultured TE13 cells as the BMI-1 siRNA groups, and a negative one was synthesized to be used as the negative control (NC) group. The untransfected group was named as the control group. BMI-1 mRNA and protein expression in esophageal cancer TE13 cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot in different groups. This study used flow cytometry assay to analyze cell cycle of transfected cells, and examined cellular growth and radiosensitivityin vitro by MTT and clone formation assay. mRNA and protein expression of p16 and CDK4 in esophageal cancer TE13 cells were detected by RT-PCR and Western blot.Results:The results of RT-PCR and Western blot showed that the expressions of BMI-1 at gene and protein levels were inhibited after silencing the BMI-1 gene. The mRNA and protein expression of BMI-1 in BMI-1 siRNA3 group were both significantly lower than that in BMI-1 siRNA1 and 2 groups. There was no significant difference in the cell proliferation among control, NC and BMI-1 siRNA3 groups. The values ofD0,Dq, and SF2 in BMI-1 siRNA3 group were 1.761, 2.122 and 0.6255, respectively, obvi-ously lower than those in control group (2.514, 2.694 and 0.8268) and those in NC group (2.506, 2.664 and 0.8231), while the value of N in BMI-1 siRNA3 group (3.336) was higher than that in control group (2.92) and that in NC group (2.895), which showed higher radiosensitivity in BMI-1 siRNA3 group. In addition, the cell cycle was arrested at G2/M phase after irradiation in control and NC groups. The percentage of G0/G1 phase in BMI-1 siRNA3 group was higher than that of control group and NC group, while the percentage of G2/M phase was lower than those in the latter. The up-regulation of p16 and down-regulation of CDK4 at gene and protein levels were detected after knockdown of BMI-1 expression by siRNA (P<0.01).Conclusion:siRNA could inhibitBMI-1 gene expression in esophageal cancer TE13 cells and enhance radiosensitivity, followed by eliminating the cell cycle arrest at G2/M stage after irradiationin vitro, which is related to the regulation of the protein expression ofp16 andCDK4.

Expression of c-myc, Bmi-1, serum insulin-like growth factor-Ⅰ and insulin-like growth factor binding protein-3 and their significances in diffuse large B-cell lymphoma / 白血病·淋巴瘤

Objective To detect the expressions of c-myc,Bmi-1,serum insulin-like growth factor-Ⅰ (IGF-Ⅰ) and insulin-like growth factor binding protein-3 (IGFBP-3) in diffuse large B-cell lymphoma (DLBCL),and to analyze their relations with clinical stages,efficacy and prognosis.Methods 102 cases of incipient patients with DLBCL and 60 patients or health examination volunteers were chosen as DLBCL group and control group,respectively.Immunohistochemical method was used to detect expressions of c-myc and Bmi-1 in DLBCL wax samples.Chemiluminescence immunoassay method was used to determine the levels of serum IGF-Ⅰ and serum IGFBP-3.The expression differences of these factors between DLBCL group and control group and their relations with pathological types,clinical stage,IPI and chemotherapy were analyzed.Results The positive rates of c-myc and Bmi-1 were 71.6 ％ (73/102) and 61.8 ％(64/102) in the tissues of DLBCL,respectively.The positive rates of c-myc and Bmi-1 in non-GCB group were higher than those in GCB group [c-myc:80.0 ％ (48/60) vs 59.5 ％ (25/42);Bmi-1:71.7 ％ (43/60) vs 50.0 ％ (21/42)].With the increase of IPI score,the expressions of c-myc and Bmi-1 were enhanced,but there were no statistical differences between Ⅲ-Ⅳ group and Ⅰ-Ⅱ group (P ＞ 0.01).The differences of 3-year progression free survival (PFS) rate and 3-year overall survival (OS) rate between c-myc gene or Bmi-1 gene normal and abnormal had statistical significance,and 3-year PFS rate and 3-year OS rate of double-hit of c-myc gene and Bmi-1 were lower.C-myc gene and Bmi-1 gene aberrant were the independent prognosis factors.The levels of serum IGF-Ⅰ and serum IGFBP-3 in DLBCL group were significantly lower than those in the control group (P ＜ 0.01),however,the levels were increased after chemotherapy (P ＜ 0.01).Serum IGF-Ⅰ and serum IGFBP-3 levels had no significant differences between non-GCB group and GCB group (P ＞ 0.01).Their levels in stage Ⅳ group or high risk group were significantly lower than those in other groups.Serum IGF-Ⅰ level and serum IGFBP-3 level had no significant differences between the c-myc gene or Bmi-1 gene abnormal group and normal group (P ＞ 0.01),but their levels were lower in both c-myc gene and Bmi-1 gene abnormal group than those in normal group.Conclusions C-myc and Bmi-1 are related with the biological characteristics and prognosis of DLBCL.Serum IGF-Ⅰ level and serum IGFBP-3 level reflect clinical stages of DLBCL and the efficacy in a certain degree.The expressions of c-myc and Bmi-1 have some correlation with the levels of serum IGF-Ⅰ and IGFBP-3 in DLBCL.

Inhibition of BMI-1 expression increases the sensitivity to doxorubicin in human hepatocellular carcinoma cells / 肿瘤

Objective: To study the effect of B cell-specific murine leukemia virus integration site-1 (BMI-1) gene expression inhibited by RNA interference on doxorubicin (Dox)-resistance of hepatocellular carcinoma cells, and to explore its related molecular mechanism. Methods: The Dox-resistant MHCC-97H cell line was established and named as 97H/Dox, while the parental MHCC-97H cell line (named as 97H) was used as the control. The drug-resistance, cell colony-forming capacity and invasive ability were measured by MTT method, cell colony formation assay and in vitro Transwell invasive experiment, respectively. The mRNA and protein levels of tumor-related genes were detected by real-time fluorescent quantitative-PCR (RFQ-PCR) and Western blotting. Then the small interference RNA (siRNA) targeting BMI-1 gene (BMI-1-siRNA) was transfected into 97H/Dox and 97H cells. After BMI-1 gene silencing, the changes of Dox-resistance of 97H/Dox and 97H cells were detected by MTT method, and the change of expressions of tumor-related proteins in 97H cells was detected by Western blotting. Results: The 97H/Dox cell line had a stable multiple-drug resistance, and its colony formation capacity was higher than that of the control cell line 97H (P < 0.05). The levels of BMI-1, ATP-binding cassette superfamily G member 2 (ABCG2) and matrix metalloproteinase-2 (MMP-2) were significantly increased in 97H/Dox cells compared with those in the control 97H cells (all P < 0.05). Knockdown of BMI-1 gene by siRNA significantly increased the sensitivity to Dox in 97H/Dox and 97H cells (both P < 0.05), and resulted in a significant reduction of the expression levels of phospho-Akt (p-Akt), phospho-c-Jun N-terminal kinase (p-JNK) and ABCG2 in 97H cells (all P < 0.05). Conclusion: The upregulation of BMI-1 gene expression may be involved in the acquisition of Dox-resistance in hepatocellular carcinoma 97H cells. Inhibition of BMI-1 expression can enhance the sensitivity to Dox in hepatocellular carcinoma cells. Therefore, interfering the expression of BMI-1 gene may be a potential strategy for enhancing the response to chemotherapy in treatment of hepatocellular carcinoma.

Knockdown of Bmi1 inhibits bladder cancer cell growth both in vitro and in vivo by blocking cell cycle at G1 phase and inducing apoptosis / 华中科技大学学报（医学）（英德文版）

Bmi1 is a member of the polycomb group family of proteins, and it drives the carcinogenesis of various cancers and governs the self-renewal of multiple types of stem cells. However, its role in the initiation and progression of bladder cancer is not clearly known. The present study aimed to investigate the function of Bmi1 in the development of bladder cancer. Bmi1 expression was detected in human bladder cancer tissues and their adjacent normal tissues (n=10) by immunohistochemistry, qRT-PCR and Western blotting, respectively. Bmi1 small interference RNA (siRNA) was synthesized and transfected into human bladder carcinoma cells (EJ) by lipofectamine 2000. The Bmil expression at mRNA and protein levels was measured in EJ cells transfected with Bmil siRNA (0, 80, 160 nmol/L) by qRT-PCR and Western blotting, respectively. Cell viability and Ki67 expression (a marker of cell proliferation) were determined in Bmi1 siRNA-transfected cells by CCK-8 assay and qRT-PCR, respectively. Cell cycle of transfected cells was flow-cytometrically determined. Immunofluorescence and Western blotting were used to detect the expression levels of cell cycle-associated proteins cyclin D1 and cyclin E in the cells. Pro-apoptotic proteins Bax and caspase 3 and anti-apoptotic protein Bcl-2 were detected by Western blotting as well. Additionally, xenograft tumor models were established by inoculation of EJ cells (infected with Bmil shRNA/pLKO.1 lentivirus or not) into nude mice. The tumor volumes were measured every other day for 14 days. The results showed that the Bmil expression was significantly increased in bladder tumor tissues when compared with that in normal tissues (P<0.05). Perturbation of Bmi1 expression by using siRNA could significantly inhibit the proliferation of EJ cells (P<0.05). Bmi1 siRNA-transfected EJ cells were accumulated in G1 phase and the expression levels of cyclin D1 and cyclin E were down-regulated. Bax and caspase-3 expression levels were significantly increased and Bcl-2 levels decreased after Bmi1 knockdown. Tumor volume was conspicuously reduced in mice injected with EJ cells with Bmi1 knockdown. Our findings indicate that Bmi1 is a potential driver oncogene of bladder cancer and it may become a potential treatment target for human bladder cancer.

Proto-oncogene Bmi-1 and non-small cell lung cancer / 国际肿瘤学杂志

B-cell specific moloney leukemia virus insertion site 1(Bmi-1)gene is a core member of the polycomb group genes,considered to be a proto-oncogene;Bmi-1 plays an important role in cell self-renewal, proliferation and apoptosis. Several studies have shown that Bmi-1 is highly expressed in non-small cell lung cancer;furthermore,the expression level of Bmi-1 is closely related to the occurrence,development,incursion and prognosis of non-small cell lung cancer. Bmi-1 is expected to become a novel tumor molecular marker,and provides a new direction for the treatment of non-small cell lung cancer.

Effect of 5-FU on expression of Bmi-1, Sca-1 and Oct-4 in human breast cancer cell line MDA-MB-468 / 临床与实验病理学杂志

Purpose To explore the relation between the expression of Bmi-1 and cancer stem cells and its relation to chemotherapy re-sistance in breast cancer. Methods MTT method was applied to detect the inhibition effect on proliferation of different concentrations (0. 01, 0. 1, 1, 10 μg/ml) of 5-Fluorouracil (5-FU) to MDA-MB-468 cells with 48 and 72 hours culture, a curve of proliferation in-hibition rate was drawn, and a suitable experiment concentration of 5-FU was chosen. MDA-MB-468 cells was serially passaged under continuous interference with the suitable concentration of 5-FU, 6 generations of cells were collected, cells with 5-FU interference were designed as experiment group and a corresponding control group with no 5-FU was set. RT-PCR and Western blot were employed to ex-amine mRNA and protein expression of Bmi-1 and Sca-1, Oct-4 in the 6 generations of cells of both control group and experiment group. Results Results of the MTT test showed that 5-FU could inhibit the proliferation of human breast cancer cell line MDA-MB-468, the 5-FU concentration of 0. 1 μg/ml was chosen as the suitable experiment concentration. RT-PCR tests showed that the differ-ences between the relative mRNA expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were not sta-tistically significant in control group (all P>0. 05) and that the differences between the relative mRNA expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were of statistical significance in experiment group cells (all P<0. 05). The mRNA expression of Bmi-1, Sca-1 and Oct-4 showed the following tendency in the 6 generations of passaged cells:decrease (1st gen-eration)—increase (2nd generation)—continuous increase (3rd generation)—decrease (4th generation)—increase (5th genera-tion)—decrease (6th generation). Western blot tests indicated that the differences between the relative protein expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were not statistically significant in control group and that the differ-ences between the relative protein expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were of sta-tistical significance in experiment group cells (all P<0. 05). The expression of Bmi-1 was positively correlated with stem cell associat-ed factors Sca-1, Oct-4 (r=1, all P<0. 01). Conclusions The expression of Bmi-1 gene is positively correlated with expression of stem cell associated factors Sca-1 and Oct-4 in breast cancer cell line MDA-MB-468 cell, and Bmi-1 may be a novel marker for cancer stem cells in breast cancer. Administration of 5-FU can affect the expression level of Bmi-1 and the ration of cancer stem cells in breast cancer cell line MDA-MB-468. Bmi-1 gene may be associated with drug resistance to chemotherapy and recurrence in breast cancer.

Effect of BMI1 Knockdown on Cell Proliferation, Apoptosis, Invasiveness, and Migration of U251 Glioma Cells / 체질인류학회지

BMI1 belongs to the polycomb-repressive complex 1 (PRC1) family of genes that are conserved chromatin silencers. These are essential for maintaining both the normal and cancerous stem cell state. In this study, we evaluated the effect of siRNA-mediated BMI1 knockdown on tumor cell properties such as invasion, migration, and apoptosis, as well as on cell signaling pathways responsible for tumor progression in the human glioma cell line, U251. Knockdown of BMI1 induced apoptosis by activating cleavage of PARP and caspase-3. It also decreased the expression of anti-apoptotic proteins, survivin, XIAP, Bcl-xL, and Mcl1. Additionally, BMI1 knockdown significantly decreased cell invasion and cell migration ability. BMI1 knockdown also decreased the phosphorylation of Akt/FOXO1/3a signaling proteins. Our results suggest that BMI1 knockdown induces apoptosis and decreases cell invasion and cell migration. Moreover, we believe these phenomenona are associated with decreased phoshorylation of Akt signaling proteins, which contributes to cancer progression.