Expression Level Of Bmi-1 Research Articles

Abstract C072: Bmi1 expression is upregulated in response to injury/stress in the pancreas

Abstract Pancreatic homeostasis is regulated in part through epigenetic mechanisms that restrict or enable access of pancreatic lineage transcription factors to their target genes. These epigenetic protein cascades are also required for regeneration of the pancreas after injury. B-cell Moloney murine leukemia virus integration site 1 (Bmi1), a central protein in the Polycomb repressor complex 1 (PRC1), has been shown to be required for the regeneration of the pancreas after injury and its absence prevents pancreatic neoplasia in mice. Previous work also suggests that Bmi1 marks a subset of acinar cells contributing to pancreatic renewal and tissue maintenance. It remains unclear how Bmi1 expression levels are regulated in response to pancreatic stress and injury. Here we assess the baseline expression of Bmi1 in pancreatic tissue with a genetic reporter mouse model as well as changes in Bmi1 mRNA levels at different time points after the induction of pancreatitis in wild-type mice via RNA in situ hybridization (RNAscope). We also compare the ability of the murine pancreas to regenerate after acute pancreatitis in the presence and absence of Bmi1. Our data indicates that rather than a specific subpopulation, most, if not all, acinar cells in the pancreas express Bmi1 during their life and specific loss of Bmi1 in the pancreas impairs regeneration after acute pancreatitis. We also show an increase in Bmi1 mRNA levels within the pancreas shortly after the induction of acute pancreatitis which reduces as the pancreas resumes its normal histology. Altogether, our data indicate that Bmi1 expression is dynamic, responsive to injury and necessary for pancreatic homeostasis and regeneration. Citation Format: Nur Muhammad Renollet, Joyce K Thompson, Emily Wu, Osama Alkhalili, Nina Steele, Filip Bednar. Bmi1 expression is upregulated in response to injury/stress in the pancreas [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C072.

Lactiplantibacillus plantarum JM113 alleviates deoxynivalenol induced intestinal damage by microbial modulation in broiler chickens

Deoxynivalenol (DON) contamination causes the grievous injury in public and animal health, poultry suffer from the greater toxin challenge. Probiotic have been considered as a potential way to mitigate the deleterious effects of DON. In this study, a total of 144 1-day-old Arbor Acres chickens were randomly assigned into 3 groups: control group, DON group (5 mg/kg DON diet), DJ group (1×109 cfu Lactiplantibacillus plantarum JM113/kg DON diet). The results showed that Lactiplantibacillus plantarum JM113 (L. plantarum JM113) increased the growth performance of 21-day-old broilers that challenged by the DON (P < 0.05), and the DON-induced disorder of jejunal morphology was recovered in DJ group (P < 0.05). Compared with the DON group, the mRNA and protein levels of Nrf2 and NQO-1 were upregulated in jejunum of DJ group broilers (P < 0.05). Meanwhile, administration of L. plantarum JM113 effectively increased the expression level of barrier-related genes, and the protein abundance of occludin and claudin1 (P < 0.05). L. plantarum JM113 restored the mRNA and protein abundance of PCNA, and proliferation-linked gene (Lgr5 and Bmi1) expression levels in jejunum of DON-insulted broilers (P < 0.05). Furthermore, administration of L. plantarum JM113 significantly enhanced the relative abundance of s_Limosilactobacillus_reuteri in jejuna of DON-challenged broilers (P < 0.05). Spearman correlation analysis showed that s_Limosilactobacillus_reuteri was positively associated with the jejunal barrier related genes (P < 0.05). In conclusion, L. plantarum JM113 alleviated the toxic effects of DON by regulating the jejunal function through microbial adjustment. Our findings proposed a viable approach to mitigating the adverse effects of deoxynivalenol exposure in broilers.

Targeting Bmi1 for Enhancing Anoikis Sensitivity and Inhibiting Metastasis in Colorectal Cancer.

Patients diagnosed with advanced metastatic colorectal cancer (CRC) confront a bleak prognosis characterized by low survival rates. Anoikis, the programmed apoptosis resistance exhibited by metastatic cancer cells, is a crucial factor in this scenario. We employed bulk flow cytometry and RT-qPCR assays, conducted in vivo experiments with mice and zebrafish, and analyzed patient tissues to examine the effects of the B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi1)-midkine (MDK) axis on the cellular response to anoikis. Bmi1 is pivotal in tumorigenesis. This study elucidated the involvement of Bmi1 in conferring anoikis resistance in CRC and explored its downstream targets associated with metastasis. Elevated levels of Bmi1 expression correlated with distant metastasis in CRC. Suppression of Bmi1 significantly diminished the metastatic potential of CRC cells. Inhibition of Bmi1 led to an increase in the proportion of apoptotic SW620 cells detached from the matrix. This effect was further enhanced by the addition of irinotecan, a topoisomerase I inhibitor. Furthermore, Bmi1 was found to synergize with MDK in modulating CRC viability, with consistent expression patterns observed in in vivo models and clinical tissue specimens. In summary, Bmi1 acted as a regulator of CRC metastatic capability by conferring anoikis resistance. Additionally, it collaborated with MDK to facilitate invasion and distant metastasis. Targeting Bmi1 may offer a promising adjunctive therapeutic strategy when administering traditional chemotherapy regimens to patients with advanced CRC.

Correlations between C-myc expression, BMI-1 expression, and vaginal microecology with HPV-DNA load in patients with different cervical lesions.

To investigate the correlations between the expressions of proto-oncogenes C-myc and B-cell-specific Moloney leukemia virus integration site-1 (BMI-1), vaginal microecology, and human papillomavirus-DNA (HPV-DNA) load in patients with different cervical lesions. A total of 51 patients with cervix squamous cell carcinoma (CSCC), 72 patients with cervical intraepithelial neoplasia (CIN) and 50 patients with normal cervix (NC) who were diagnosed or admitted between Jan. 1st 2020 and Dec. 31st 2022 at the Suzhou Hospital of Integrated Traditional Chinese and Western Medicine were selected and divided into three groups, i.e., the CSCC group, the CIN group and the NC group, for a retrospective analysis. Hybrid capture 2 (hc2) was used to detect the HPV-DNA load in each group. Immunohistochemistry was performed to detect C-myc and BMI-1 expressions in each group. The indicators of vaginal microecology in patients were compared among groups to analyze the correlations between C-myc, BMI-1 expressions, vaginal microecology and HPV-DNA load. The HPV-DNA load and expression levels of positive C-myc and BMI-1 in the CSCC group were all higher than those of the CIN and NC groups (P<0.05). The detection rate of lactobacillus in the CSCC group was lower than that of the CIN and NC groups. The percentages of leukocyte esterase (LE) positivity and pH ≥4.6 were higher in the CSCC group than those in the CIN and NC groups (P<0.05). The difference in the detection rate of spores among the three groups was not significant (P>0.05). Both C-myc and BMI-1 scores were positively correlated with HPV-DNA load in the 173 samples. The proto-oncogenes C-myc and BMI-1 were highly expressed in the cervical tissues of CIN and CSCC patients, whose vaginal microecology was also altered. Both may play an important role in the progression of cervical lesions.

Unfolded protein response inhibits KAT2B/MLKL-mediated necroptosis of hepatocytes by promoting BMI1 level to ubiquitinate KAT2B.

Unfolded protein response (UPR) plays an important role in the pathogenesis of many liver diseases. BMI1 has a liver protection effect, but whether it participates in the regulation of hepatocyte death through UPR is not well defined. Herein, the endoplasmic reticulum stress model was established by inducing hepatocyte line (MIHA) with tunicamycin (TM, 5 µg/ml). Cell counting kit-8 assay and flow cytometry were used to evaluate the viability and apoptosis of hepatocytes. The expression levels of BMI1, KAT2B, and proteins related to UPR (p-eIF2α, eIF2α, ATF4, and ATF6), NF-κB (p65 and p-p65), apoptosis (cleaved caspase-3, bcl-2, and bax) and necroptosis (p-MLKL and MLKL) were determined by Western blot. The relationship between KAT2B and BMI1 was determined by co-immunoprecipitation and ubiquitination assay. The results showed that TM not only promoted UPR, apoptosis, and necroptosis in hepatocytes but also upregulated the expression levels of BMI1 and KAT2B and activated NF-κB pathway. BAY-117082 reversed the effects of TM on viability, apoptosis, NF-κB pathway, and BMI1 but strengthened the effects of TM on KAT2B/MLKL-mediated necroptosis. BMI1 promoted the ubiquitination of KAT2B, and BMI1 overexpression reversed the effects of TM on viability, apoptosis, and KAT2B/MLKL-mediated necroptosis. In summary, overexpression of BMI1 promotes the ubiquitination of KAT2B to block the MLKL-mediated necroptosis of hepatocytes.

Alpha-tocopherol enhances spermatogonial stem cell proliferation and restores mouse spermatogenesis by up-regulating BMI1.

Spermatogonial stem cells (SSCs) are essential for maintaining reproductive function in males. B-lymphoma Mo-MLV insertion region 1 (BMI1) is a vital transcription repressor that regulates cell proliferation and differentiation. However, little is known about the role of BMI1 in mediating the fate of mammalian SSCs and in male reproduction. This study investigated whether BMI1 is essential for male reproduction and the role of alpha-tocopherol (α-tocopherol), a protective agent for male fertility, as a modulator of BMI1 both in vitro and in vivo. Methyl thiazolyl tetrazolium (MTT) and 5-ethynyl-2'-deoxyuridine (EDU) assays were used to assess the effect of BMI1 on the proliferative ability of the mouse SSC line C18-4. Real-time polymerase chain reaction (PCR), western blotting, and immunofluorescence were applied to investigate changes in the mRNA and protein expression levels of BMI1. Male mice were used to investigate the effect of α-tocopherol and a BMI1 inhibitor on reproduction-associated functionality in vivo. Analysis revealed that BMI1 was expressed at high levels in testicular tissues and spermatogonia in mice. The silencing of BMI1 inhibited the proliferation of SSCs and DNA synthesis and enhanced the levels of γ-H2AX. α-tocopherol enhanced the proliferation and DNA synthesis of C18-4 cells, and increased the levels of BMI1. Notably, α-tocopherol rescued the inhibition of cell proliferation and DNA damage in C18-4 cells caused by the silencing of BMI1. Furthermore, α-tocopherol restored sperm count (Ctrl vs. PTC-209, p = 0.0034; Ctrl vs. PTC-209 + α-tocopherol, p = 0.7293) and normalized sperm malformation such as broken heads, irregular heads, lost and curled tails in vivo, as demonstrated by its antagonism with the BMI1 inhibitor PTC-209. Analysis demonstrated that α-tocopherol is a potent in vitro and in vivo modulator of BMI1, a transcription factor that plays an important role in in SSC proliferation and spermatogenesis. Our findings identify a new target and strategy for treating male infertility that deserves further pre-clinical investigation.

Establishment of a patient-derived organoid model and living biobank for nasopharyngeal carcinoma

Background Recurrent nasopharyngeal carcinoma (NPC) remains a major challenge for clinicians and scientists. Tumor organoid is a revelational disease model that highly resembled the heterogeneity and histopathological characteristics of original tumors. This study aimed to optimize the modeling process of patient-derived NPC organoids (NPCOs), and establish a living-biobank of NPCs to study the mechanism and explore the more effective treatment of the disease.MethodsSixty-two fresh NPC tissue samples and 15 normal mucosa samples were collected for 3-dimensional (3D) organoid culture. The organoids were confirmed using hematoxylin and eosin assays. The expression levels of CD133, CD44, BMI-1, and Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) were detected by immunohistochemistry (IHC) and in situ hybridization (ISH). Recurrent NPCOs were frozen in liquid nitrogen for 6 months and then resuscitated and passaged.ResultsWe identified a novel two-step enzymatic strategy for the treatment of NPC and nasal mucosa specimens and an optimal medium for culturing NPCOs and nasal mucosa organoids (NMOs). Organoid cultures were generated from 34 primary NPC samples, 28 recurrent NPC samples, and 15 normal mucosa samples. The success rates for primary NPCO, recurrent NPCO, and NMO formation were 47.06%, 81.25%, and 86.5%, respectively. All the NPCOs were EBER positive and CK7 negative. Recurrent NPCOs had higher expressions of stem cell markers, including BMI-1, CD44, and CD133. Additionally, recurrent NPCOs could be cultured to passage 4 and frozen and revived repeatedly, while primary NPCOs were challenging to culture.Conclusions In summary, we successfully established a living biobank using the NPCO model, which has enormous potential in basic and clinical research on NPC.

The expression and clinical significance of Bmi-1 gene in oral leukoplakia with different prognosis

Objective: To detect the expression of Bmi-1 in oral leukoplakia (OL) cells and tissues, and analyze its role and clinical significance in the malignant transformation of OL. Methods: Immunohistochemistry was used to evaluate Bmi-1 expression in OL samples from 109 patients (51 males, 58 females, age range: 18-74 years) who were treated in the Department of Stomatology, the Affiliated Wuxi People's Hospital of Nanjing Medical University and the Center of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, between 1996 and 2018. The correlation between Bmi-1 expression level and clinicopathological parameters and prognosis in patients with OL was analyzed. The mRNA and protein expression levels of Bmi-1 gene in normal oral mucosal epithelial cells, OL cells, oral squamous cell carcinoma (OSCC) cells, OL tissues and paired adjacent normal tissues were detected by real-time PCR and Western blotting. The effects of Bmi-1 on the proliferation, colony formation and apoptosis were investigated by silencing expression of Bmi-1 in OL cell lines Leuk-1. Results: The protein level of Bmi-1 in OL tissue with severe and mild dysplasia was statistically different (6 819±994 vs 4 713±372, P=0.017). The OSCC-free survival rate of OL patients with high Bmi-1 expression was 65.5% (36/55), which was lower than that of OL patients with low Bmi-1 expression (88.9%, 48/54, P=0.003). Multivariate Cox proportional analysis indicated that Bmi-1 expression was the independent predictor for malignant transformation of OL (HR=2.522, 95%CI: 1.128-5.640, P=0.024). The mRNA level of Bmi-1 in OL specimens was 0.455±0.120, which was higher than that in paired adjacent normal tissues (0.063±0.009, P=0.014). The Bmi-1 mRNA level in malignant transformed OL specimens was (1.405±0.397), which was higher than that in untransformed OL specimens (0.145±0.017, P<0.001). After transfection of Bmi-1-shNC and Bmi-1-shRNA2 adenovirus into OL cell line Leuk-1, there were significant differences in the number of clone formation (824±40 vs 414±38, P=0.002) and apoptosis rate (17.7%±2.3% vs 36.0%±2.0%, P=0.004). Conclusions: The up-regulation of Bmi-1 expression promotes the malignant biological behavior of OL cells. Bmi-1 expression can be used as a predictor for malignant transformation of OL.

Repression of the Antioxidant Pyrroloquinoline Quinone in Skin Aging Induced by Bmi-1 Deficiency.

It is uncertain whether Bmi-1 deficiency could lead to skin aging by redox imbalance and DNA damage. In this study, we first confirmed that Bmi-1 had a relatively high expression level in the skin and Bmi-1 expression levels gradually decreased with age. Then, we studied the role of Bmi-1 in the skin using a Bmi-1−/− mouse model. Bmi-1−/− mice were supplemented with or without pyrroloquinoline quinone (PQQ) for 5 weeks, and their skin phenotypes were compared with Bmi1−/− and wild-type littermates. Our results showed that Bmi-1−/− mice displayed decreased vertical thickness of skin, sparse hair follicles, and thinner and more irregular collagen bundles. Mechanistically, increased oxidative stress with reducing antioxidant capacity and induced DNA damage occurred in Bmi-1−/− mice. Subsequently, this would lead to reduced cell proliferation, increased cell senescence and matrix metalloproteinases (MMPs), and the degradation of fibroblast function and further reduce collagen synthesis. All pathological alterations in the skin of Bmi-1−/− mice were alleviated by PQQ supplementation. These results demonstrated that Bmi-1 might play a key role in protection from skin aging by maintaining redox balance and inhibiting DNA damage response and will be a novel and potential target for preventing skin aging.

Preclinical Evaluation of the First in Class BMI1 Inhibitor PTC-028 Confirms Potent Efficacy to Target BMI1-Addiction in Multiple Myeloma

Background:Treatment modalities for multiple myeloma (MM) patients suffering from refractory or high-risk disease are still limited. Although translational research efforts previously identified key players and promising drug targets in MM biology (e.g. IRF4, MYC, FOXM1), direct modulation of these factors is impeded by the lack of clinically effective inhibitors. Initially linked to the pathogenesis of MM more than a decade ago, the polycomb group protein BMI1 represents a prominent intrinsic driver of MM without a suitable clinical grade inhibitor. We recently confirmed BMI1 overexpression as a hallmark of MM and proved its essential role in MM cell survival using a small molecule inhibitor that affects BMI1 transcript levels (PTC209). Based on these observations, here, we explored the anti-myeloma efficacy of the first in class BMI1 protein inhibitor PTC028 and confirmed its applicability to target a so far not drug-able key molecule in MM.Methods:The anti-MM efficacy of PTC028 (kindly provided by PTC Therapeutics Inc.) was studied in vitro using human MM cell lines (HMCLs) and primary MM cells. Candidate gene expression levels were analyzed by quantitative PCR (qPCR), Western Blot and/or flow cytometry (FC). Mechanistic studies were conducted via FC and immunoblot experiments. Confirmatory studies are employed using lentiviral transduction of BMI1 overexpression or knockout plasmids, respectively.Results:PTC028 induced a time-dependent reduction of BMI1 protein levels in HMCLs. Evaluation of the in vitro efficacy demonstrated potent anti-MM activity in all primary MM cells and HMCLs tested (median IC50: 39 nM, range: 11-102 nM). This activity persisted in the presence of bone marrow stromal cells and in proteasome inhibitor (PI) resistant HMCLs. Importantly, median IC50 values were significantly reduced compared to PTC209 (median IC50 680 nM, P <0.05) confirming superior activity of PTC028. We also observed a significant correlation between PTC028 IC50 values and the reduction of BMI1 protein levels in HMCLs (R=0.86, P=0.01), suggesting that a rapid drop of BMI1 levels could serve as predictive marker for treatment efficacy.Mechanistically, treatment with PTC028 led to an accumulation of cells in the G2/M phase of the cell cycle and induction of apoptosis (verified by the presence of cleaved PARP and depolarization of the mitochondrial membrane potential). To better segregate the sequence of these events we performed time course experiments with U266 and KMS-12-BM cells. This demonstrated rapid induction of G2/M cell cycle arrest (evident 6h post treatment) and subsequent induction of apoptosis. Western Blot analysis demonstrated accumulation of CDK1 and Cyclin B1 in line with the G2/M cell cycle stop. In addition, we evaluated MCL1 protein levels due to its known degradation during mitotic arrest and indeed observed a time dependent downregulation of this key MM survival factor. In contrast, neither BIM nor BAX were found to be deregulated. Further validation of these results was obtained by qPCR analysis. PTC028 induced rapid upregulation of mitosis associated genes (CCNB1, AURKA, BIRC5) 6h and 24h post treatment indicating mitotic arrest which was accompanied by MCL1 downregulation. No impact was found on the gene expression levels of BMI1 and other cell cycle (CCND1, CDKN2A, CDKN1A, CDKN1B) or apoptosis (BAX, BIM, NOXA) related genes.Due to the close interaction between BMI1, MYC and FOXM1 we were finally interested whether PTC028 also affects these key factors. Intriguingly, PTC028 treatment led to rapid downregulation of both proteins suggesting that targeting of BMI1 via PTC028 offers a novel strategy to attack this MM high-risk network.Conclusion:This study demonstrates potent preclinical activity of the first in class BMI1 inhibitor PTC028 in a panel of HMCLs, primary MM cells, PI-resistant HMCLs and in the presence of BMSCs. This suggests efficacy in the context of the MM microenvironment and drug resistance. Moreover, our data point to significant impact on a currently not targetable high-risk network consisting of BMI1, MYC and FOXM1. These results strongly support further evaluation of PTC028 in the clinical setting. Detailed results about the impact of PTC028 on BMI1 associated signaling networks as well as preliminary in vivo efficacy results will be provided at the meeting. DisclosuresWeetall:PTC Therapeutics: Employment. Branstrom:PTC Therapeutics: Employment. Zojer:Celgene, Janssen, Amgen, Takeda, BMS: Consultancy, Honoraria, Research Funding.

Polycomb group protein Bmi1 is required for the neuronal differentiation of mouse induced pluripotent stem cells.

Induced pluripotent stem cells (iPSCs) reprogrammed by somatic cells may be used as a potentially novel treatment regimen in stem cell regenerative medicine, particularly in the central nervous system (CNS). In the present study, iPSCs were generated using mouse embryonic fibroblasts by ectopic overexpression of Sox-2, Oct-3/4, Klf-4 and c-Myc, and cultured under the same conditions as that used for embryonic stem cells. The neuronal differentiation capacity of mouse iPSCs was examined, and the involvement of the formation of embryoid bodies was assessed. The results suggested that after 15 days of neuronal inducement, Nestin, Vimentin and Glast protein expression levels were significantly increased in the mouse iPSC-derived cells. Additionally, Bmi1, which is selectively expressed in differentiated postnatal adult stem cells. such as hematopoietic stem cells and neural stem cells, was required for establishment of the neuronal differentiation of mouse iPSCs. In order to assess the effects of Bmi1 in neuronal differentiation, Bmi1 expression levels were inhibited with the small molecule PTC-209. The results showed that inhibition of Bmi1 expression reduced the expression of neuronal markers, such as Nestin, compared with the controls. These results suggested that mouse iPSCs can be induced to achieve neuronal differentiation. More interestingly, Bmi1 was required during the neuronal differentiation of mouse iPSCs.

BMI1-Inhibitor PTC596 in Combination with MCL1 Inhibitor S63845 or MEK Inhibitor Trametinib in the Treatment of Acute Leukemia.

Simple SummaryPrognosis for acute myeloid leukemia (AML) patients is poor, particularly in TP53 mutated AML, secondary, relapsed, and refractory AML, and in patients unfit for intensive treatment, thus highlighting an unmet need for novel therapeutic approaches. Targeting the stem cell oncoprotein BMI1 in leukemic cells may represent a promising novel treatment option for poor risk AML patients, especially in combination with other targeted therapies. Here we tested the BMI1 inhibitor PTC596 in combination with a variety of targeted therapies in AML cell lines and patient samples in vitro. In addition, we defined the biomarkers of response to the combination treatments in the leukemic cells. The combination treatment with the BMI1 inhibitor PTC596 and the MCL1 inhibitor S63845 may be an effective treatment in CD34+ adverse risk AML with elevated MN1 gene expression and MCL1 protein levels, while combination treatment with BMI1 inhibitor PTC596 and the MEK inhibitor trametinib may be more effective in CD34+ adverse risk AML with elevated BMI1 gene expression and MEK protein levels. The determination of gene and protein expression levels in leukemic cells as biomarkers of response to targeted combination therapies may be helpful to optimize treatment efficacy.Purpose: Prognosis for acute myeloid leukemia (AML) patients is poor, particularly in TP53 mutated AML, secondary, relapsed, and refractory AML, and in patients unfit for intensive treatment, thus highlighting an unmet need for novel therapeutic approaches. The combined use of compounds targeting the stem cell oncoprotein BMI1 and activating the tumor suppressor protein p53 may represent a promising novel treatment option for poor risk AML patients. Experimental Design: The BMI1 inhibitor PTC596, MCL1 inhibitor S63845, and MEK inhibitor trametinib, as well as the p53 activator APR-246 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells. AML cells represented all major morphologic and molecular subtypes including FLT3-ITD and FLT3 wild type, NPM1 mutant and wild type, as well as TP53 mutant and wild type AML cell lines and a variety of patient derived AML cells. Results: AML cell lines were variably susceptible to PTC596 and to combination treatments with PTC596 and MCL1 inhibitor S63845, MEK inhibitor trametinib, or TP53 activator APR-246, independent of TP53 mutational status. Susceptibility of patient samples for PTC596 in combination with S63845 or trametinib was significant for the majority of adverse risk primary and secondary AML with minimal efficacy in favorable risk AML, and correlated significantly with CD34 positivity of the samples. BMI1 and MN1 gene expression, and MCL1 and MEK1 protein levels were identified as biomarkers for response to PTC596 combination treatments. Conclusions: The combination of PTC596 and S63845 may be an effective treatment in CD34+ adverse risk AML with elevated MN1 gene expression and MCL1 protein levels, while PTC596 and trametinib may be more effective in CD34+ adverse risk AML with elevated BMI1 gene expression and MEK protein levels.

Neuronal Bmi-1 is critical for melatonin induced ubiquitination and proteasomal degradation of α-synuclein in experimental Parkinson's disease models

Epigenetic polycomb repressor complex-1 subunit BMI-1 plays a pivotal role in the process of gene repression to maintain the self-renewal and differentiation state of neurogenic tissues. Accumulating reports links lower expression of BMI-1 fails to regulate the repression of anti-oxidant response genes disrupt mitochondrial homeostasis underlying neurodegeneration. Interestingly, this negative relation between BMI-1 function and neurodegeneration is distinct but has not been generalized as a potential biomarker particularly in Parkinson's disease (PD). Hyperphosphorylated BMI-1 undergoes canonical polycomb E3 ligase function loss, thereby leads to reduce monoubiquitylation of histone 2A at lysine 119 (H2AK119ub) corroborates cellular accumulation of α-synuclein protein phosphorylated at serine 129 (pα-SYN (S129). In general, neuroprotectant suppressing pα-SYN (S129) level turns ineffective upon depletion of neuronal BMI-1. However, it has been observed that our neuroprotectant exposure suppresses the cellular pα-SYN (S129) and restore the the BMI-1 expression level in neuronal tissues. The pharmacological inhibition and activation of proteasomal machinery promote the cellular accumulation and degradation of neuronal pα-SYN (S129), respectively. Furthermore, our investigation reveals that accumulated pα-SYN (S129) are priorly complexed with BMI-1 undergoes ubiquitin-dependent proteasomal degradation and established as key pathway for therpeutic effect in PD. These findings linked the unestablished non-canonical role of BMI-1 in the clearance of pathological α-SYN and suspected to be a novel therapeutic target in PD.

Prognostic Significance of ALDH1, Bmi1, and OCT4 Expression in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma.

Background:Increasing evidence suggests the involvement of cancer stem cells (CSCs) in both oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). Among the various CSC markers, aldehyde dehydrogenase (ALDH) 1, B cell-specific Moloney murine leukaemia virus integration site 1 (Bmi1), and octamer-binding protein 4 (OCT4) have been noted to increase in OSCC. The aim of the study was to analyze ALDH1, Bmi1, and OCT4 expression in OED and OSCC with clinicopathologic correlation and survival analysis.Methods:A total of 40 cases each of OED and OSCC were retrieved from departmental archives. Expression of ALDH1, Bmi1, and OCT4 was analyzed using immunohistochemistry and was correlated with clinicopathological parameters. A follow-up ranging from 6 to 52 months was considered for Kaplan-Meier survival analysis. The log-rank test was performed to analyze significant difference in survival rates.Results:The expression levels of ALDH1, Bmi1, and OCT4 increased significantly from OED through OSCC (P < .05). The expression of ALDH1 and OCT4 showed a significant correlation with lymph node metastasis. Positive cases of ALDH1 showed a significantly reduced survival rate compared to cases showing negative expression. Kaplan-Meier survival analysis showed a significant reduction of survival rate (P = .00) in patients showing a positive expression for all the 3 markers.Conclusion:ALDH1 and OCT4 could be used as individual prognostic markers for assessing prognosis. ALDH1, Bmi1, and OCT4 could be used as a collective panel of markers to enable surgeons in predicting the prognosis of patients and thereby carry out prompt follow-up for such cases.

BMI1-Mediated Pemetrexed Resistance in Non-Small Cell Lung Cancer Cells Is Associated with Increased SP1 Activation and Cancer Stemness.

Lung cancer is the leading cause of cancer death worldwide and the therapeutic strategies include surgery, chemotherapy and radiation therapy. Non-small cell lung cancers (NSCLCs) account for around 85% of cases of lung cancers. Pemetrexed is an antifolate agent that is currently used as the second line chemotherapy drug in the treatment of advanced NSCLC patients with a response rate of 20–40%. The search for any combination therapy to improve the efficacy of pemetrexed is required. The existence of cancer stem cells (CSCs) is considered as the main reason for drug resistance of cancers. In this study, we first found that pemetrexed-resistant NSCLC cells derived from A549 cells displayed higher CSC activity in comparison to the parental cells. The expression of CSC related proteins, such as BMI1 or CD44, and the epithelial–mesenchymal transition (EMT) signature was elevated in pemetrexed-resistant NSCLC cells. We next discovered that the overexpression of BMI1 in A549 cells caused the pemetrexed resistance and inhibition of BMI1 by a small molecule inhibitor, PTC-209, or transducing of BMI1-specific shRNAs suppressed cell growth and the expression of thymidylate synthase (TS) in pemetrexed-resistant A549 cells. We further identified that BMI1 positively regulated SP1 expression and treatment of mithramycin A, a SP1 inhibitor, inhibited cell proliferation, as well as TS expression, of pemetrexed-resistant A549 cells. Furthermore, overexpression of BMI1 in A549 cells also caused the activation of EMT in and the enhancement of CSC activity. Finally, we demonstrated that pretreatment of PTC-209 in mice bearing pemetrexed-resistant A549 tumors sensitized them to pemetrexed treatment and the expression of Ki-67, BMI1, and SP1 expression in tumor tissues was observed to be reduced. In conclusion, BMI1 expression level mediates pemetrexed sensitivity of NSCLC cells and the inhibition of BMI1 will be an effective strategy in NSCLC patients when pemetrexed resistance has developed.

Genistein inhibits lung cancer cell stem-like characteristics by modulating MnSOD and FoxM1 expression.

Manganese superoxide dismutase (MnSOD) promotes invasive and migratory activities by upregulating Forkhead box protein M1 (FoxM1) expression. The present study investigated whether modulation of MnSOD and FoxM1 expression was responsible for the antitumor effects of genistein on cancer stem-like cells (CSLCs) derived from non-small cell lung cancer cells (NSCLCs). Spheroids prepared from H460 or A549 cells were defined as lung cancer stem-like cells (LCSLCs) and were treated with genistein. The Cell Counting Kit-8 assay was performed to assess human lung fibroblast IMR-90 cell proliferation, as well as NSCLC H460 and A549 cell proliferation following treatment with genistein. MnSOD, FoxM1, cluster of differentiation (CD)133, CD44, BMI1 proto-oncogene, polycomb ring finger (Bmi1) and Nanog homeobox (Nanog) protein expression levels were examined via western blotting. The sphere formation assay was conducted to evaluate LCSLC self-renewal potential, and LSCLC migratory and invasive activities were analyzed using the wound healing and Transwell invasion assays, respectively. Knockdown and overexpression of MnSOD and FOXM1 via short hairpin-RNA or cDNA transfection were performed. The results indicated that genistein (80 and 100 µM) suppressed H460 and A549 cell viability compared with IMR-90 cells. Sub-cytotoxic concentrations of genistein (20 and 40 µM) inhibited sphere formation activity and decreased the protein expression levels of CD133, CD44, Bmi1 and Nanog in LCSLCs compared with the control group. Genistein also suppressed the migratory and invasive activities of LCSLCs compared with the control group. MnSOD and FoxM1 overexpression antagonized the effects of genistein (40 µM), whereas MnSOD and FoxM1 knockdown enhanced the inhibitory effects of genistein (20 µM) on CSLC characteristics of LCSLCs. Overall, the results suggested that genistein suppressed lung cancer cell CSLC characteristics by modulating MnSOD and FoxM1 expression levels.

Proliferative ability and accumulation of cancer stem cells in oral submucous fibrosis epithelium.

The driving force of the malignant transformation of epithelial cells during oral submucous fibrosis (OSF) is an unsettled debate. We hypothesized that the expression and accumulation of cancer stem cells (CSCs) are accompanied by epithelial atrophy in OSF. The expression levels of Ki67 (proliferation marker), SOX2, and Bmi1 (CSC marker) in the epithelium during the early, middle, and late stages of OSF were measured by immunohistochemistry. At the same time, we focused on the expression of three proteins in OSF patients with benign hyperkeratosis and epithelial dysplasia. The clinical cohort study showed upregulated expression of the proliferation-associated protein Ki67 in atrophic epithelium in patients with OSF. The expression levels of SOX2 and Bmi1 showed an increasing trend in the progression of OSF. Ki67, SOX2, and Bmi1 were highly expressed in OSF tissues with dysplasia. Moreover, the three proteins were located at the epithelial and mesenchymal junctions, and their expression showed a positive correlation with each other. The results suggest that CSC accumulation could be accompanied by epithelial atrophy during OSF, which may be responsible for the driving forces for OSF carcinogenesis.

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

BackgroundAcute 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.MethodsThe 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).ResultsCompared 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).ConclusionsTaken 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.

Long noncoding RNA DANCR knockdown inhibits proliferation, migration and invasion of glioma by regulating miR-135a-5p/BMI1

BackgroundGlioma is the most common and aggressive primary brain tumor with high mortality rate around the world. LncRNAs have been identified to play key roles in tumorigenesis in various cancers, including glioma. However, the precise mechanism of DANCR in progression of glioma remains poorly defined.MethodsThe expression levels of DANCR, miR-135a-5p and BMI1 were measured by qRT-PCR in glioma tissues and cells. Cell proliferation, migration and invasion were detected by CCK-8 assay and transwell assay, respectively. The possible binding sites of miR-135a-5p and DANCR or BMI1 were predicted by online software and verified using luciferase report assay and RNA immunoprecipitation (RIP) assay. Western blot analysis was carried out to detect the protein of BMI1 expression. A xenograft tumor model was established to investigate the functions of DANCR in glioma progression in vivo.ResultsDANCR was upregulated and miR-135a-5p was downregulated in glioma tissues and cells. Knockdown of DANCR inhibited cell proliferation, migration and invasion in glioma cells. In addition, miR-135a-5p was a direct target of DANCR, and its elevated expression could reverse miR-135a-5p inhibition-mediated progression of glioma. Moreover, miR-135a-5p could specially bind to BMI1, and the expression of BMI1 was obviously elevated in glioma tissues and cells. Furthermore, DANCR acted as a ceRNA to regulate BMI1 expression and BMI1-mediated effects on progression of glioma by sponging miR-135a-5p. Besides, inhibition of DANCR limited tumor growth by regulating miR-135a-5p and BMI1 expression in vivo.ConclusionDANCR knockdown inhibited cell proliferation, migration and invasion in glioma cells through regulating miR-135a-5p/BMI1 axis, providing viable therapeutic avenues for treatment of glioma.

The Study of SALL4 Gene and BMI-1 Gene Expression in Acute Myeloid Leukemia Patients.

In acute myeloid leukemia (AML), many genes have been studied as prognostic markers. SALL4 is expressed constitutively in human leukemia cell lines and primary AML cells. BMI-1 is expressed highly in purified hematopoietic stem cells (HSCs), and its expression declines with differentiation. To study the expression levels of SALL4 and BMI-1 and their clinical significance in patients with AML. The study was performed with 60 patients newly diagnosed with AML and 50 control individuals. SALL4 and BMI-1 expression detection were performed using real-time polymerase chain reaction (PCR). The expression of SALL4 and BMI-1 was significantly higher in cases of AML and showed a strong association with failure to achieve complete remission (CR) or with relapse (P = .02, P = .03, respectively). In multivariate analysis, these genes were the most powerful independent predictors of poor prognosis (P = .01 for SALL4, P = .02 for BMI-1). SALL4 and BMI-1 are significant prognostic factors in AML and could be strong targets for novel types of therapy.