Moloney Murine Leukemia Virus Insertion Research Articles

B-cell specific Moloney murine leukemia virus insertion site 1 contributes to invasion, metastasis, and poor prognosis in salivary adenoid cystic carcinoma

Background/purposeUpregulation of B-cell specific Moloney murine leukemia virus insertion site 1 (BMI-1) has been involved in the invasion, metastasis, and poor prognosis of many cancers. The aim of this study was to evaluate the levels and clinical significance of BMI-1 in saliva of patients with salivary adenoid cystic carcinoma (SACC), and to analyze biological function and mechanism of BMI-1 in the invasion and metastasis of SACC. Materials and methodsThe levels of BMI-1 in saliva and tumor tissues of SACC patients were determined. The correlation of salivary BMI-1 levels with clinicopathological parameters and clinical outcomes in patients with SACC was analyzed. Additionally, the effects of BMI-1 on wound-healing, transwell invasion, and epithelial-mesenchymal transition (EMT)-related protein expression in vitro as well as on tumorigenicity and experimental lung metastasis in vivo were investigated through exogenous overexpression and silencing of BMI-1 in SACC cells. ResultsBMI-1 levels increased in saliva and tumor tissues in SACC patients with invasion or metastasis. High salivary BMI-1 levels were correlated with poor TNM stage, poor overall survival, and disease-free survival. Exogenous expression of BMI-1 in SACC-83 promoted its migration and invasion, while silencing BMI-1 in SACC-LM inhibited its migration and invasion in vitro and suppressed tumorigenesis and lung metastasis in vivo. Furthermore, BMI-1 regulated the expression of EMT-related proteins in SACC. ConclusionOur study shows that BMI-1 can serve as a valuable biomarker to identify tumor invasion and metastasis in SACC, predict its prognosis, and act as a promising therapeutic target for SACC.

Genome-wide association study identifies a novel BMI1A QTL allele that confers FLC expression diversity in Arabidopsis thaliana.

Identification and understanding of the genetic basis of natural variations in plants are essential for comprehending their phenotypic adaptation. Here, we report a genome-wide association study (GWAS) of FLOWERING LOCUS C (FLC) expression in 727 Arabidopsis accessions. We identified B LYMPHOMA MOLONEY MURINE LEUKEMIA VIRUS INSERTION REGION 1 HOMOLOG 1A (BMI1A) as a causal gene for one of the FLC expression quantitative trait loci (QTLs). Loss of function in BMI1A increases FLC expression and delays flowering time at 16 °C significantly compared with the wild type (Col-0). BMI1A activity is required for histone H3 lysine 27 trimethylation (H3K27me3) accumulation at the FLC, MADS AFFECTING FLOWERING 4 (MAF4), and MAF5 loci at low ambient temperature. We further uncovered two BMI1A haplotypes associated with the natural variation in FLC expression and flowering time at 16 °C, and demonstrated that polymorphisms in the BMI1A promoter region are the main contributor. Different BMI1A haplotypes are strongly associated with geographical distribution, and the low ambient temperature-sensitive BMI1A variants are associated with a lower mean temperature of the driest quarter of their collection sites compared with the temperature-non-responsive variants, indicating that the natural variations in BMI1A have adaptive functions in FLC expression and flowering time regulation. Therefore, our results provide new insights into the natural variations in FLC expression and flowering time diversity in plants.

Chondroitin Sulphate/Dermatan Sulphate Proteoglycans: Potential Regulators of Corneal Stem/Progenitor Cell Phenotype In Vitro.

Chondroitin sulphate (CS) proteoglycans with variable sulphation-motifs along their glycosaminoglycan (GAG) chains are closely associated with the stem cell niche of articular cartilage, where they are believed to influence the characteristics of the resident stem cells. Here, we investigated the immunohistochemical distribution of hybrid CS/dermatan sulphate (DS) GAGs in the periphery of the adult chicken cornea, which is the location of the cornea's stem cell niche in a number of species, using a monoclonal antibody, 6C3, that recognises a sulphation motif-specific CS/DS GAG epitope. This revealed positive labelling that was restricted to the subepithelial corneal stroma, as well as nearby bony structures within the sclera, called ossicles. When cultivated on cell culture dishes coated with 6C3-rich CS/DS, corneal stromal cells (keratocytes) that had been isolated from embryonic chicken corneas formed circular colonies, which took several days to reach confluency. A flow cytometric analysis of these keratocytes revealed changes in their expression levels of the indicative stem cell markers, Connexin 43 (Cx43), Paired Box 6 (PAX6), B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1), and C-X-C Chemokine Receptor 4 (CXCR4) suggestive of a less-differentiated phenotype compared with expression levels in cells not exposed to CS/DS. These findings support the view that CS/DS promotes the retention of a stem cell phenotype in corneal cells, much as it has been proposed to do in other connective tissues.

Natural Compounds with BMI1 Promoter Inhibitory Activity from Mammea siamensis and Andrographis paniculata.

A new coumarin derivative (1) and 30 known compounds were isolated from Mammea siamensis and Andrographis paniculata, guided by B cell-specific Moloney murine leukemia virus insertion region 1 (BMI1) promoter inhibitory activity. Among the isolated compounds, 15 compounds showed BMI1 promoter inhibitory activity, and five compounds were found to be cytotoxic. 14-Deoxy-11,12-dehydroandrographolide (18) was highly cytotoxic to DU145 cells with an IC50 value of 25.4 µM. Western blotting analysis of compound 18 in DU145 cells suggested that compound 18 suppresses BMI1 expression.

TERT/BMI1-transgenic human dermal papilla cells enhance murine hair follicle formation in vivo

BackgroundDermal papilla cells (DPCs) are one type of mesenchymal cells; they play a key role on hair follicle induction. Their hair inductivity and proliferation abilities are rapidly lost during the 2-dimensional culture. Cell senescence is induced by inadequate culture conditions and telomere shortening. We previously reported that overexpression of TERT coding telomerase reverse transcriptase and BMI1 coding human B-cell-specific Moloney murine leukemia virus insertion region 1 (BMI1) avoided senescence of murine DPC and restored hair inductive activity. ObjectiveTo evaluate the function of TERT and BMI1 in the human DPCs (hDPCs). MethodsCultured hDPCs obtained from human scalp hair were transduced with TERT alone (hDP-T), BMI1 alone (hDP-B), both TERT and BMI1 (hDP-TB) and empty vector (hDP-E). The hair inductive activity of those cells was assessed by chamber assay in vivo. Gene expressions were analyzed by quantitative PCR (q-PCR). ResultshDP-TB proliferated more than hDP-T and hDP-B in vitro and only hDP-TB showed hair inductivity in vivo. Moreover, the expressions of VCAN, CTNNB1, LEF1, FGF7 and VEGFA in hDP-TB were elevated compared to those in hDP-E. ConclusionOverexpression of both TERT and BMI1 extends the life span of cultured hDPCs and ameliorates their hair inducing ability on mouse hair follicles.

Effects of BMI1 Gene on Regulating Apoptosis, Invasion, and Migration of HEC-1B Cells Induced by Ionizing Radiation.

The aim of this study was to examine the role of B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1) gene in regulating the apoptosis, invasion, and migration of human endometrial adenocarcinoma cell line (HEC-1B) cells induced by ionizing radiation. The expression of BMI1 mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR), and the positive expression of BMI1 was detected by immunohistochemistry (IHC) staining. HEC-1 B cells were randomly divided into three groups: control group, BMI1 overexpression group, and BMI1 inhibitor group. Cell proliferation was detected by cell counting kit-8 (CCK-8); cell migration and invasion were detected by Transwell test; cell apoptosis was detected by flow cytometry; and the expression of MMP2, MMP7, MMP9, Rock1, RhoA, P53, P21, and Bax protein was detected by the western blot. The results suggested that the expression of BMI1 mRNA and tissue positive in endometrial cancer tissues was increased significantly. After ionizing radiation, compared with the control group, the proliferation, cell migration, and invasion of HEC-1B cells were increased significantly in the BMI1 overexpression group, while the proliferation, cell migration, and invasion of HEC-1B cells were decreased significantly in BMI1 inhibitor group. The apoptosis rate of BMI1 overexpression group was decreased significantly, while the BMI1 inhibitor group was increased significantly. The levels of MMP2, MMP7, MMP9, Rock1, RhoA and p53, p21, Bax protein in BMI1 overexpression group were significantly increased, while the levels of MMP2, MMP7, MMP9, Rock1, RhoA and p53, p21, Bax protein in BMI1 inhibitor group were significantly decreased. BMI1 is highly expressed in endometrial cancer tissues, and inhibiting BMI1 expression can reduce the proliferation, migration, and invasion of HEC-1B cells after ionizing radiation and promote apoptosis, which offers new insights into the clinical radiotherapy of tumors.

Canine Natural Killer Cell-Derived Exosomes Exhibit Antitumor Activity in a Mouse Model of Canine Mammary Tumor.

Natural killer (NK) cells are key immune cells engaged in fighting infection and malignant transformation. In this study, we found that canine NK cell-derived exosomes (NK-exosomes) separated from activated cytotoxic NK cell supernatants express specific markers including CD63, CD81, Alix, HSP70, TSG101, Perforin 1, and Granzyme B. We examined the antitumor effects of NK-exosomes in an experimental murine mammary tumor model using REM134 canine mammary carcinoma cell line. We observed changes in tumor size, tumor initiation, progression, and recurrence-related markers in the control, tumor group, and NK-exosome-treated tumor group. We found that the tumor size in the NK-exosome-treated tumor group decreased compared with that of the tumor group in the REM134-driven tumorigenic mouse model. We observed significant changes including the expression of tumorigenesis-related markers, such as B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1), vascular endothelial growth factor (VEGF), matrix metallopeptidase-3 (MMP-3), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), multidrug resistance protein (MDR), tumor suppressor protein p53 (p53), proliferating cell nuclear antigen (PCNA), and the apoptotic markers, B cell lymphoma-2 associated X (Bax) and B cell lymphoma-extra large (Bcl-xL) belonging to the Bcl-2 family, in the tumor group compared with those in the control group. The expression of CD133, a potent cancer stem cell marker, was significantly higher than that of the control. By contrast, the NK-exosome-treated tumor group exhibited a significant reduction in Bmi-1, MMP-3, IL-1β, IL-6, TNF-α, Bax, Bcl-xL, and PCNA expression compared with that in the tumor group. Furthermore, the expression of CD133, which mediates tumorigenesis, was significantly decreased in the NK-exosome-treated tumor group compared with that in the tumor group. These findings indicate that canine NK-exosomes represent a promising therapeutic tool against canine solid tumors, including mammary carcinoma.

BTF3-mediated regulation of BMI1 promotes colorectal cancer through influencing epithelial-mesenchymal transition and stem cell-like traits

The critical roles of transcription factors in cell differentiation and the delineation of cell phenotypes have been reported. The current study aimed to characterize the functions of the basic transcription factor 3 (BTF3) gene and its regulation of the intestinal stem cell marker B cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) gene in colorectal cancer (CRC). Stem cell-like traits and epithelial-mesenchymal transition (EMT) of cultured human CRC cell line HCT116 were evaluated by CD133+ subpopulation counting, colony formation, tumorosphere generation, and expression of EMT-specific markers and stem cell markers. The interaction of BTF3 with BMI1 was analyzed. BTF3 was overexpressed in CRC tissues, which was associated with poor patient survival. BTF3 knockdown impaired the retention of stem cell-like traits of HCT116 and inhibited the EMT of HCT116 cells. BMI1 expression changed in a BTF3-dependent manner, and its overexpression could partially restore stem cell-like traits and EMT of cultured HCT116 cells after BTF3 knockdown. In parallel, treatment with the BMI1 inhibitor PTC-209 mimicked the effects of BTF3 knockdown on stem cell-like traits and EMT of cultured HCT116 cells. Together, these results support the notion that BTF3 and BMI1 are potential therapeutic targets to limit CRC metastasis.

Leucine-rich repeat-containing G protein-coupled receptor 5 marks different cancer stem cell compartments in human Caco-2 and LoVo colon cancer lines.

BACKGROUNDColon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers. It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5)-expressing stem cells, these so-called “tumour-initiating” cells, reminiscent in their properties of the normal intestinal stem cells (ISCs), may explain the apparent heterogeneity of colon cancer cell lines. Also, colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5. Furthermore, in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.AIMTo investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.METHODSA portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines (Caco-2 and LoVo). These cells were then characterized according to their proliferation capacity, gene expression signatures of ISC markers, and their tumorigenic properties in vivo and in vitro.RESULTSThe data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2, but not from the LoVo, cell lines, in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog (+4 crypt) stem cells. This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny. Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein (EYFP) from this cell line exhibit tumorigenic-like properties in vivo and in vitro. In contrast, cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties. Thus, cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells, but not LoVo cells.CONCLUSIONOur findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines. Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data. We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.

Circular RNA circ-0016068 Promotes the Growth, Migration, and Invasion of Prostate Cancer Cells by Regulating the miR-330-3p/BMI-1 Axis as a Competing Endogenous RNA.

Prostate cancer is a common neoplasm worldwide, and the sixth most common cause of cancer-related mortality. Biomarkers for earlier diagnosis and improved treatment alternatives are critical. Circular RNAs (circRNAs) can promote the growth and progression of various cancers; however, prostate cancer-specific circRNAs have not been found. We identified circ-0016068, a circRNA that was expressed more strongly in prostate cancer tumors vs. normal paired tissue, and confirmed its relatively high expression in prostate cancer tissues and cell lines. We also discerned that circ-0016068 promotes the epithelial-to-mesenchymal transition (EMT) and the growth, migration, and invasion of prostate cancer cells in vitro; and promotes the growth and metastasis of tumors in a mouse model of prostate cancer. Moreover, we found that circ-0016068 competes with the B-lymphoma Moloney murine leukemia virus insertion region-1 (BMI-1) for binding to miR-330-3p. In so doing, circ-0016068 sequesters miR-330-3p and frees BMI-1 to enhance the proliferation, migration, and invasion of prostate cancer cells, and the metastasis of xenograft tumors. These results suggest that circ-0016068 may be a promising diagnostic biomarker for early stage prostate cancer and a potential target for novel cancer therapeutics.

Bmi1 Severs as a Potential Tumor-Initiating Cell Marker and Therapeutic Target in Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a frequent malignant tumor with low 5-year overall survival. Targeting ESCC tumor-initiating cells (TICs) may provide a new research avenue to achieve better therapeutic effects of ESCC. However, the identity and characteristics of ESCC TICs remain poorly understood. Through genetic lineage tracing approach, we found that a group of Moloney murine leukemia virus insertion site 1- (Bmi1-) expressing cell populations present in the invasive front of the esophageal epithelium, providing a continuous flow of tumor cells for ESCC. Subsequently, we found that ablation of Bmi1+ cells from mice with ESCC led to inhibition of tumor growth. In addition, our results demonstrated that PTC-209, an inhibitor of Bmi1, was able to inhibit ESCC progression when combined with cisplatin. In summary, our data suggest that Bmi1+ cells serve as TICs in ESCC.

BMI1-KLF4 axis deficiency improves responses to neoadjuvant concurrent chemoradiotherapy in patients with rectal cancer

PurposeNeoadjuvant concurrent chemoradiotherapy (CCRT) is a gold standard treatment for patients with stage II/III rectal cancer. B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) is a member of the polycomb group of proteins that are involved in regulating gene expression. High levels of BMI1 have been demonstrated to contribute to the malignant phenotypes of several cancers; however, its relevance in rectal cancer treated with CCRT is largely unknown. Methods and materialsWe used two patient cohorts to address the clinical relevance of BMI1 in human cancers. In addition, HT-29 and HCT-116 cells were chosen as our in vitro models to verify the role of BMI1 in cell response to ionizing radiation. Stemness-related proteins were analyzed by western blotting and cell survival was determined using clonogenic assays. ResultsBMI1 overexpression was found to significantly correlate with advanced pre-treatment nodal status (N1-N2; p < 0.001), post-treatment tumor stage (T1-T2; p = 0.015), inferior tumor regression grade (p = 0.001), and also an independent prognosis factor in 172 rectal cancer patients receiving CCRT. Serial cell-based functional examination indicated that BMI1 deficiency sensitized cells to radiation treatment by modulating the gene expression of Kruppel-like factor 4 (KLF4) and enhanced radiosensitivity in microsatellite stable (MSS) colorectal cancers. Overexpression of KLF4 partially overcame BMI1-deficiency-mediated γ-H2AX expression after ionizing radiation exposure. Consistent with in vitro data, an analysis of an additional 30 rectal cancer tissue specimens revealed a positive correlation between BMI1 and KLF4 (p = 0.02). ConclusionHigher levels of BMI1 are associated with poor therapeutic response and adverse outcomes in rectal cancer patients receiving CCRT.

Expression and correlation of Bmi-1, AEG-1 and FHIT in bladder transitional cell carcinoma.

BackgroundTo explore the expression and correlation of B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1), astrocyte elevated gene-1 (AEG-1) and fragile histidine triad (FHIT) in bladder transitional cell carcinoma (BTCC).MethodsForty-six tissue samples were obtained from patients diagnosed with primary bladder cancer during the first radical cystectomy between June 2010 and January 2014. The expression of Bmi-1, AEG-1 and FHIT in normal tissues and BTCC tissues in different histological cell types, clinical pathological stages and lymph node metastatic status were evaluated by quantitative real time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry. Relationships between Bmi-1, AEG-1 and FHIT were determined using linear correlation coefficient.ResultsThe results of qRT-PCR showed the relative expression of Bmi-1 and AEG-1 were higher and the expression of FHIT was lower in BTCC tissues than those in normal tissues, whether in different histological cell types, clinical pathological stages or lymph node metastatic status (P<0.05). Similarly, the up-regulated expression of Bmi-1 and AEG-1 and down-regulated expression of FHIT in BTCC tissues were observed by the Western blot and immunohistochemistry compared with normal tissues (P<0.05). Linear correlation analysis showed the expression of Bmi-1 was positively correlated with AEG-1 (r>0.90, P<0.01), which was negatively correlated with the expression of FHIT, respectively (r=−0.84, P<0.05).ConclusionsThe study demonstrated the up-regulated expression of Bmi-1 and AEG-1 and the down-regulated expression of FHIT in BTCC tissues. The interaction of Bmi-1, AEG-1 and FHIT may involve in the tumorigenesis, progression and invasion of BTCC through NF-κB/MMP-9 pathway.

The Polycomb Protein Bmi1 Plays a Crucial Role in the Prevention of 1,25(OH)2 D Deficiency-Induced Bone Loss.

We analyzed the skeletal phenotypes of heterozygous null Cyp27b1 (Cyp27b1+/- ) mice and their wild-type (WT) littermates to determine whether haploinsufficiency of Cyp27b1 accelerated bone loss, and to examine potential mechanisms of such loss. We found that serum 1,25-dihydroxyvitamin D [1,25(OH)2 D] levels were significantly decreased in aging Cyp27b1+/- mice, which displayed an osteoporotic phenotype. This was accompanied by a reduction of expression of the B lymphoma Moloney murine leukemia virus (Mo-MLV) insertion region 1 (Bmi1) at both gene and protein levels. Using chromatin immunoprecipitation (ChIP)-PCR, electrophoretic mobility shift assay (EMSA) and a luciferase reporter assay, we then showed that 1,25(OH)2 D3 upregulated Bmi1 expression at a transcriptional level via the vitamin D receptor (VDR). To determine whether Bmi1 overexpression in mesenchymal stem cells (MSCs) could correct bone loss induced by 1,25(OH)2 D deficiency, we overexpressed Bmi1 in MSCs using Prx1-driven Bmi1 transgenic mice (Bmi1Tg ) mice. We then compared the bone phenotypes of Bmi1Tg mice on a Cyp27b1+/- background, with those of Cyp27b1+/- mice and with those of WT mice, all at 8 months of age. We found that overexpression of Bmi1 in MSCs corrected the bone phenotype of Cyp27b1+/- mice by increasing osteoblastic bone formation, reducing osteoclastic bone resorption, increasing bone volume, and increasing bone mineral density. Bmi1 overexpression in MSCs also corrected 1,25(OH)2 D deficiency-induced oxidative stress and DNA damage, and cellular senescence of Cyp27b1+/- mice by reducing levels of reactive oxygen species (ROS), elevating serum total superoxide dismutase levels, reducing the percentage of γH2 A.X, p16, IL-1β, and TNF-α-positive cells and decreasing γH2A.X, p16, p19, p53, p21, IL-1β, and IL-6 expression levels. Furthermore, 1,25(OH)2 D stimulated the osteogenic differentiation of MSCs, both ex vivo and in vitro, from WT mice but not from Bmi1-/- mice and 1,25(OH)2 D administration in vivo increased osteoblastic bone formation in WT, but not in Bmi1 -/- mice. Our results indicate that Bmi1, a key downstream target of 1,25(OH)2 D, plays a crucial role in preventing bone loss induced by 1,25(OH)2 D deficiency. © 2019 American Society for Bone and Mineral Research.

MicroRNA-218 regulates the epithelial-to-mesenchymal transition and the PI3K/Akt signaling pathway to suppress lung adenocarcinoma progression by directly targeting BMI-1.

To investigate the role of miR-218 in the development of lung adenocarcinoma (LA) and its underlying mechanism. Fifty-two pairs of human LA samples and adjacent para-carcinoma tissue samples were collected from our hospital between June 2015 and March 2017. Meanwhile, one normal human pulmonary epithelial cell line BEAS-2B and four human LA cell lines (H1299, PC-9, A549, and SPC-A1) were cultured. The cells' ability of proliferation and migration was detected by MTT assays and Transwell assays, respectively. The target gene was clarified by dual-luciferase reporter assay. The related protein and mRNA expression levels were detected by immunohistochemistry (IHC), Western blot and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. At last, the tumor xenograft model was made for further exploring the mechanism. MiR218 expressions were notably reduced in LA tissues in comparison with controls. In addition, the declined miR218 expressions were correlated with the poor OS and worse clinicopathological parameters of LA patients. Furthermore, miR218 overexpression could suppress the proliferation, migration and invasion capacities of LA cells via regulation of PI3K/Akt signaling pathway and epithelial-mesenchymal transition (EMT) respectively. Results in the current study also revealed that miR-218 upregulation could suppress the tumor growth rate and tumor size of LA mice. B-lymphoma Moloney murine leukemia virus insertion region-1 (BMI-1) was confirmed to be a direct target for miR-218 and upregulated in LA tissues, which indicated the poor prognosis of LA patients. MiR-218 exerted anti-tumor functions in LA partially via the regulation of BMI-1, suggesting that BMI-1/miR-218 axis may provide a novel insight into tumorigenesis and the basis for the development of miRNA-targeting therapies against LA.

B-lymphoma moloney murine leukemia virus insertion region 1 promotes epithelial-mesenchymal transition and invasion of colorectal cancer cell HT-29 cells in inflammatory microenvironment

Objective Investigate the effect and mechanism of B-lymphoma Moloney murine leukemia virus insertion region 1 (Bmi-1) on tumor migration and epithelial-mesenchymal transition (EMT) of HT-29 cells in inflammatory microenvironment. Methods Detect the gene and protein levels of Bmi-1, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by qPCR and Western blotingt respectively, and the levels of TNF-α and IL-6 in culture medium supernatant by enzyme linked immunosorbent assay (ELISA). Evaluate the proliferation, migration and invasion in HT-29 cells by MTT assay and Transwell assays. EMT-related markers and nuclear factor-κB (NF-κB) pathway key proteins were detected by Western blotting. Results The mRNA levels of Bmi-1, TNF-α and IL-6 was significantly increased in HT29 cells after THP-1 Conditioned-Medium (THP-1-CM) stimulation (1.86±0.08 vs.1.00±0.05, 2.38±0.13 vs.1.00±0.14, 3.00±0.15 vs.1.00±0.05, P<0.01, respectively), as well as the protein levels[1.68±0.08 vs.1.00±0.05, (73±4) pg/ml vs. (32±4) pg/ml, (140±9) pg/ml vs. (42±9) pg/ml, P<0.01, respectively]. Knockdown of Bmi-1 expression remarkably repressed the secretion of cytokines[ (31±3), (56±8) pg/ml]. THP-1-CM accelerated the protein synthesis of vimentin, N-cadherin and phosphorylation of NF-κB, enhanced invasion and metastasis. Inversely, knockdown of Bmi-1 expression remarkably repressed THP-1-CM-induced EMT and NF-κB activity, but had no effect on cell proliferation in vitro. Conclusion Bmi-1 may be involved in the cytokines secretion of HT-29 cells induced by THP-1-CM, and has effect on migration and invasion through epithelial-mesenchymal transformation, which is related to NF-κB pathway activity. Bmi-1 can be treated as a potential molecular target for metastatic colorectal cancer. Key words: B-lymphoma moloney murine leukemia virus insertion region 1 gene; Tumor inflammatory microenvironment; Metastatic colorectal cancer

Acute exposure to deoxynivalenol inhibits porcine enteroid activity via suppression of the Wnt/β-catenin pathway

The intake of food containing deoxynivalenol frequently causes damage to the intestine, the renewal of which is driven by intestinal stem cells (ISCs). Nevertheless, the toxicity of deoxynivalenol on ISCs and its underlying mechanisms remain to be elucidated. As pigs are the most sensitive animals to deoxynivalenol, we used piglets for investigation in this study. Here, we show that intestinal epithelial cell activity, B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi1) protein level, and Wnt/β-catenin pathway activity were suppressed with acute expose to deoxynivalenol. We further established a novel system for porcine crypt isolation and ex vivo cultivation. Crypts and crypt cells expanded and budded with typical enteroid morphologies under this system. Our results show that both acute in vivo and in vitro administration of deoxynivalenol significantly decreased enteroid activity. Simultaneously, protein levels of β-catenin and leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5) in enteroids were reduced by deoxynivalenol exposure. In conclusion, we established a reliable culture system for porcine enteroids and demonstrated for the first time that the activity of ISCs and the Wnt/β-catenin pathway is sensitively suppressed by acute deoxynivalenol exposure.

Clinicopathological and Prognostic Significance of Expression of B-Cell-Specific Moloney Murine Leukemia Virus Insertion Site 1 (BMI-1) Gene and Protein in Gastrointestinal Stromal Tumors.

BackgroundGastrointestinal stromal tumor (GIST) is an uncommon visceral sarcoma that arises predominantly in the gastrointestinal tract. Since GISTs are encountered infrequently and inflexible to traditional therapy, the aim of the present study was to explore the correlation of B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI-1) mRNA and BMI-1 protein levels with the clinicopathological characteristics and prognosis significance of GISTs.Material/MethodsGIST tissues and normal tissues were collected from 156 patients who had undergone surgical treatment. RT-qPCR and immunohistochemistry were used to measure the BMI-1 mRNA and protein levels in GIST tissues and normal tissues. Univariate survival analysis was used for determination of the factors that affect prognosis of GIST patients. Cox proportional hazards model was plotted to determine the independent risk factors for prognosis of GIST patients.ResultsThe BMI-1 mRNA and protein levels in GIST tissues were higher than those in normal tissues. BMI-1 mRNA and positive protein levels were correlated with the National Institutes of Health (NIH) risk grade, tumor diameter and infiltration, and metastasis. There was a short survival period for the patients with a positive protein level and a high mRNA level of BMI-1. The site of primary tumor, tumor diameter, NIH risk grade, infiltration, and metastasis, as well as BMI-1 mRNA and protein levels were independent risk factors for prognosis of GIST patients.ConclusionsTaken together, these findings suggest there might be a relationship between BMI-1 mRNA and protein levels, and clinicopathological characteristics, including NIH risk grade, tumor size as well as infiltration and metastasis, of GIST patients. In addition, BMI-1 mRNA and protein levels were identified as independent risk factors for prognosis of GIST patients.

B lymphoma Moloney murine leukemia virus insertion region 1: An oncogenic mediator in prostate cancer

B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1), a core member of polycomb repressive complex 1 (PRC1), has been intensely investigated in the field of cancer epigenetics for decades. Widely known as a critical regulator in cellular physiology, BMI1 is essential in self-renewal and differentiation in different lineages of stem cells. BMI1 also plays a significant role in cancer etiology for its involvement in pathological progress such as epithelial–mesenchymal transition (EMT) and cancer stem cell maintenance, propagation, and differentiation. Importantly, overexpression of BMI1 is predictive for drug resistance, tumor recurrence, and eventual therapy failure of various cancer subtypes, which renders the pharmacological targeting at BMI1 as a novel and promising therapeutic approach. The study on prostate cancer, a prevalent hormone-related cancer among men, has promoted enormous research advancements in cancer genetics and epigenetics. This review summarizes the role of BMI1 as an oncogenic and epigenetic regulator in tumor initiation, progression, and relapse of prostate cancer.

Lactobacillus plantarum IS-10506 activates intestinal stem cells in a rodent model.

This study investigated the probiotic effect of Lactobacillus plantarum IS-10506 in activating and regenerating leucine-rich repeat-containing G-protein-coupled receptor (Lgr)5- and B lymphoma Moloney murine leukaemia virus insertion region (Bmi)1-expressing intestinal stem cells in rodents following Escherichia coli serotype 055:B5 lipopolysaccharide (LPS) exposure. Male Sprague-Dawley rats (n=64) were randomised into control (KN), LPS (KL), probiotic + LPS (KL-Pr), and sequential probiotic + LPS + probiotic (KPR-7L) groups. Microencapsulated L. plantarum IS-10506 (2.86×1010 cfu/day) was administered via a gastric tube once daily for up to 7 days, and LPS (250 ng/kg body weight) was administered via a gastric tube on the first day of the experiment to all but the KN group. On day 3, 4, 6, and 7, four rats per group were sacrificed, and Lgr5, Bmi1, extracellular signal-regulated kinase (ERK), and β-catenin expression in the ileum was assessed by immunohistochemistry. LPS treatment reduced Lgr5 (P≤0.05) and Bmi1 (P=0.000) levels in intestinal epithelial cells, whereas probiotic treatment increased levels of Lgr5 (KPR-7L, P=0.008) and Bmi1 (KL-Pr, P=0.008; and KPR-7L, P=0.000). Lgr5 expression was upregulated in the KL-Pr group on day 3, 4, 6, and 7 (P=0.056). Additionally, ERK levels were elevated in Bmi1- and Lgr5-expressing cells in rats treated with probiotics (KL-Pr and KPR-7L), whereas β-catenin levels were increased in Lgr5-expressing cells from KPR-7L rats and in Bmi1-expressing cells from KL-Pr and KPR-7L rats on day 3 and 4. These results demonstrated that the probiotic L. plantarum IS-10506 activated intestinal stem cells to counter inflammation and might be useful for maintaining intestinal health, especially when used as a prophylactic agent.