Prognostic role of high Bmi-1 expression in Asian and Caucasian patients with solid tumors: a meta-analysis

Glucose and Cell Context-Dependent Impact of BMI-1 Inhibitor PTC-209 on AKT Pathway in Endometrial Cancer Cells

PURPOSE

In our study, the glucose and cell context-dependent impact of the BMI-1 inhibitor PTC-209 on the AKT pathway in endometrial cancer cells was determined.

METHODS

The expression of BMI-1 was inhibited by PTC-209 in endometrial cancer cells HEC-1A and Ishikawa stimulated with insulin and grown in different glucose concentrations. The migration, invasion, viability, and proliferative potential after PTC-209 treatment was assessed using wound-healing, Transwell assay, Matrigel-coated inserts, and MTT tests. Chromatin immunoprecipitation was used to determine the localization of BMI-1 protein at promoter sites of the genes tested.

RESULTS

BMI-1 inhibition caused an increase in PHLPP1/2 expression and a decrease in phospho-AKT level in both cell lines. The glucose concentration and insulin stimulation differentially impact the AKT pathway through BMI-1 in cells differing in PTEN statuses. The expression of BMI-1 is dependent on the glucose concentration and insulin stimulation mostly in PTEN positive HEC-1A cells. In high glucose concentrations, BMI-1 affects AKT activity through PHLPPs and in hypoglycemia mostly through PTEN. BMI-1 inhibition impacts on genes involved in SNAIL, SLUG, and CDH1 and reduces endometrial cancer cells' migratory and invasive potential.

CONCLUSIONS

Our results indicate that the relationship between BMI-1 and phosphatases involved in AKT regulation depends on the glucose concentration and insulin stimulation.

Targeting cancer stemness mediated by BMI1 and MCL1 for non-small cell lung cancer treatment

Lung cancer is the leading cause of cancer‐associated death, with a global 5‐year survival rate <20%. Early metastasis and recurrence remain major challenges for lung cancer treatment. The stemness property of cancer cells has been suggested to play a key role in cancer plasticity, metastasis and drug‐resistance, and is a potential target for drug development. In this study, we found that in non‐small cell lung cancer (NSCLC), BMI1 and MCL1 play crucial roles of cancer stemness including invasion, chemo‐resistance and tumour initiation. JNK signalling serves as a link between oncogenic pathway or genotoxicity to cancer stemness. The activation of JNK, either by mutant EGFR or chemotherapy agent, stabilized BMI1 and MCL1 proteins through suppressing the expression of E3‐ubiquitin ligase HUWE1. In lung cancer patient samples, high level of BMI1 is correlated with poor survival, and the expression of BMI1 is positively correlated with MCL1. A novel small‐molecule, BI‐44, was developed, which effectively suppressed BMI1/MCL1 expressions and inhibited tumour formation and progression in preclinical models. Targeting cancer stemness mediated by BMI1/MCL1 with BI‐44 provides the basis for a new therapeutic approach in NSCLC treatment.

Roles of BMI1 in the Initiation, Progression, and Treatment of Hepatocellular Carcinoma

Liver cancer has high rates of morbidity and mortality, and its treatment is a global health challenge. Hepatocellular carcinoma (HCC) accounts for 90% of all primary liver cancer cases. B-lymphoma Mo-MLV insertion region 1 (BMI1) has been identified as a proto-oncogene, which contributes to the initiation and progression of many malignant tumors. BMI1 expression is upregulated in HCC, and it influences the occurrence and development of HCC by various mechanisms, such as the INK4a/ARF locus, NF-κB signaling pathway, and PTEN/PI3K/AKT signaling pathway. In addition, the expression of BMI1 is related to prognosis and recurrence of HCC. Hence, there is clear evidence that BMI1 is a novel and valid therapeutic target for HCC. Accordingly, the development of therapeutic strategies targeting BMI1 has been a focus of recent research, providing new directions for HCC treatment. This review summarizes the role of BMI1 in the occurrence and treatment of HCC, which will provide a basis for using BMI1 as a potential target for the development of therapeutic strategies for HCC.

High BMI1 Expression with Low CD8+ and CD4+ T Cell Activity Could Promote Breast Cancer Cell Survival: A Machine Learning Approach

BMI1 is known to play a key role in the regulation of stem cell self-renewal in both endogenous and cancer stem cells. High BMI1 expression has been associated with poor prognosis in a variety of human tumors. The aim of this study was to reveal the correlations of BMI1 with survival rates, genetic alterations, and immune activities, and to validate the results using machine learning. We investigated the survival rates according to BMI1 expression in 389 and 789 breast cancer patients from Kangbuk Samsung Medical Center (KBSMC) and The Cancer Genome Atlas, respectively. We performed gene set enrichment analysis (GSEA) with pathway-based network analysis, investigated the immune response, and performed in vitro drug screening assays. The survival prediction model was evaluated through a gradient boosting machine (GBM) approach incorporating BMI1. High BMI1 expression was correlated with poor survival in patients with breast cancer. In GSEA and in in silico flow cytometry, high BMI1 expression was associated with factors indicating a weak immune response, such as decreased CD8+ T cell and CD4+ T cell counts. In pathway-based network analysis, BMI1 was directly linked to transcriptional regulation and indirectly linked to inflammatory response pathways, etc. The GBM model incorporating BMI1 showed improved prognostic performance compared with the model without BMI1. We identified telomerase inhibitor IX, a drug with potent activity against breast cancer cell lines with high BMI1 expression. We suggest that high BMI1 expression could be a therapeutic target in breast cancer. These results could contribute to the design of future experimental research and drug development programs for breast cancer.

BMI1 in the heart: Novel functions beyond tumorigenesis

The BMI1 protein, a member of the PRC1 family, is a well recognised transcriptional suppressor and has the capability of maintaining the self-renewal and proliferation of tissue-specific stem cells. Numerous studies have established that BMI1 is highly expressed in a variety of malignant cancers and serves as a key regulator in the tumorigenesis process. However, our understanding of BMI1 in terminally differentiated organs, such as the heart, is relatively nascent. Importantly, emerging data support that, beyond the tumor, BMI1 is also expressed in the heart tissue and indeed exerts profound effects in various cardiac pathological conditions. This review gives a summary of the novel functions of BMI1 in the heart, including BMI1-positive cardiac stem cells and BMI1-mediated signaling pathways, which are involved in the response to various cardiac pathological stimuli. Besides, we summarize the recent progress of BMI1 in some novel and rapidly developing cardiovascular therapies. Furtherly, we highlight the properties of BMI1, a therapeutic target proved effective in cancer treatment, as a promising target to alleviate cardiovascular diseases.

Personalized Medicine-Current and Emerging Predictive and Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide and is heterogeneous both morphologically and molecularly. In an era of personalized medicine, the greatest challenge is to predict individual response to therapy and distinguish patients likely to be cured with surgical resection of tumors and systemic therapy from those resistant or non-responsive to treatment. Patients would avoid futile treatments, including clinical trial regimes and ultimately this would prevent under- and over-treatment and reduce unnecessary adverse side effects. In this review, the potential of specific biomarkers will be explored to address two key questions—1) Can the prognosis of patients that will fare well or poorly be determined beyond currently recognized prognostic indicators? and 2) Can an individual patient’s response to therapy be predicted and those who will most likely benefit from treatment/s be identified? Identifying and validating key prognostic and predictive biomarkers and an understanding of the underlying mechanisms of drug resistance and toxicity in CRC are important steps in order to personalize treatment. This review addresses recent data on biological prognostic and predictive biomarkers in CRC. In addition, patient cohorts most likely to benefit from currently available systemic treatments and/or targeted therapies are discussed in this review.

Prognostic Biomarkers for Gastric Cancer: An Umbrella Review of the Evidence

Introduction: Biomarkers are biological molecules entirely or partially participating in cancerous processes that function as measurable indicators of abnormal changes in the human body microenvironment. Aiming to provide an overview of associations between prognostic biomarkers and gastric cancer (GC), we performed this umbrella review analyzing currently available meta-analyses and grading the evidence depending on the credibility of their associations. Methods: A systematic literature search was conducted by two independent investigators of the PubMed, Embase, Web of Science, and Cochrane Databases to identify meta-analyses investigating associations between prognostic biomarkers and GC. The strength of evidence for prognostic biomarkers for GC were categorized into four grades: strong, highly suggestive, suggestive, and weak. Results: Among 120 associations between prognostic biomarkers and GC survival outcomes, only one association, namely the association between platelet count and GC OS, was supported by strong evidence. Associations between FITC, CEA, NLR, foxp3+ Treg lymphocytes (both 1- and 3-year OS), CA 19-9, or VEGF and GC OS were supported by highly suggestive evidence. Four associations were considered suggestive and the remaining 108 associations were supported by weak or not suggestive evidence. Discussion: The association between platelet count and GC OS was supported by strong evidence. Associations between FITC, CEA, NLR, foxp3+ Treg lymphocytes (both 1- and 3-year OS), CA 19-9, or VEGF and GC OS were supported by highly suggestive evidence, however, the results should be interpreted cautiously due to inadequate methodological quality as deemed by AMSTAR 2.0.

Association of Elevated Peripheral Blood Micronucleus Frequency and Bmi-1 mRNA Expression with Metastasis in Iranian Breast Cancer Patients

Background:

In order to find cytogenetic and molecular metastasis biomarkers detectable in peripheral blood the spontaneous genomic instability expressed as micronuclei and Bmi-1 expression in peripheral blood of breast cancer (BC) patients were studied in different stages of the disease compared with unaffected first-degree relatives (FDRs) and normal control.

Methods:

The Cytokinesis Block Micronuclei Cytome (CBMN cyt) and nested real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assays, were respectively used to measure genomic instability and Bmi-1 gene expression in 160 Iranian individuals comprised of BC patients in different stages of the disease, unaffected FDRs and normal control groups.

Result:

The frequency of micronuclei and Bmi-1 expression were dramatically higher in distant metastasis compared with non-metastatic BC. In spite of micronucleus frequency with no association with lymph node (LN) involvement and hormone receptor status, the Bmi-1 expression level was higher in LN positive and triple negative patients.

Conclusion:

Our results indicate that increased genomic instability expressed as micronuclei and higher Bmi-1 expression in peripheral blood are associated with metastasis in breast cancer. Therefore implementation of micronucleus assay and Bmi-1 expression analysis in blood as possible cytogenetic and molecular biomarkers in clinical level may potentially enhance the quality of management of patients with breast cancer.

MicroRNA-203 Increases Cell Radiosensitivity via Directly Targeting Bmi-1 in Hepatocellular Carcinoma

BACKGROUND

B-cell-specific moloney leukemia virus insertion site 1 (Bmi-1) plays important roles in various cancers, but its regulation through microRNAs (miRNAs) and its functions in hepatocellular carcinoma (HCC) remains unclear.

METHODS

We evaluated the expression and prognostic significance of Bmi-1 in HCC by using tissue samples and The Cancer Genome Atlas (TCGA) data sets. The relationship between miRNAs and Bmi-1 was verified by bioinformatics prediction and immunofluorescence. Colony formation and apoptosis assays were used to reveal the effect of miR-203 on radiosensitivity.

RESULTS

The Bmi-1 mRNA and protein were upregulated in HCC tissues. Cox regression multivariate analyses showed that Bmi-1 overexpression was an independent prognostic parameter for HCC patients. The expression level of Bmi-1 was negatively associated with miR-203 levels in HCC tissues. Dual-luciferase reporter assays showed that miR-203 could target the 3' untranslated region (3'-UTR) of Bmi-1 directly. Overexpression of miR-203 in HepG2 and Smmc-7721 cells increases their sensitivity to ionizing radiation in vitro and in vivo. Moreover, the improved cell radiosensitivity induced by miR-203 could be rescued by restoration of Bmi-1 expression.

CONCLUSIONS

Bmi-1 could improve the predictive accuracy for HCC patients' survival. Moreover, miR-203 enhance cell radiosensitivity in vitro and in vivo by targeting Bmi-1 in HCC.

Bmi-1 overexpression as an efficient prognostic marker in patients with nonsmall cell lung cancer

BACKGROUND

The prognostic effect of B-cell-specific Moloney leukemia virus insertion site 1 (Bmi-1) in patients with nonsmall cell lung cancer (NSCLC) remains controversial. We thus performed a meta-analysis to reveal the correlation between Bmi-1 with clinical features and overall survival (OS) in NSCLC.

METHODS

Relevant studies were searched through PubMed, Embase, and Web of Science. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) as well as odds ratios (ORs) and 95% CIs were calculated by using STATA version 12.0.

RESULTS

Fourteen studies consisting of 1323 patients were included for quantitative analysis. The results showed that Bmi-1 was significantly associated with tumor size (n = 7, OR = 1.79, 95% CI = 1.19-2.71, P = .005, fixed effect), poor differentiation (OR = 1.61, 95% CI = 1.11-2.33, P = .011, fixed effect), and distant metastasis (n = 4, OR = 4.69, 95% CI = 1.52-14.41, P = .007, fixed effect). In addition, high Bmi-1 expression also predicted poor OS (HR = 1.62, 95% CI = 1.14-2.3, P < .001). There was no significant publication bias for any of the analyses.

CONCLUSION

In conclusion, Bmi-1 overexpression was correlated with tumor size, poor differentiation, distant metastasis, and worse OS in NSCLC. Therefore, Bmi-1 could be recommended as an efficient prognostic marker for NSCLC.

Identification of Biomarkers for Breast Cancer Using Databases

Breast cancer is one of the major causes of cancer death in women. Many studies have sought to identify specific molecules involved in breast cancer and understand their characteristics. Many biomarkers which are easily measurable, dependable, and inexpensive, with a high sensitivity and specificity have been identified. The rapidly increasing technology development and availability of epigenetic informations play critical roles in cancer. The accumulated data have been collected, stored, and analyzed in various types of databases. It is important to acknowledge useful and available data and retrieve them from databases. Nowadays, many researches utilize the databases, including The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Surveillance, Epidemiology and End Results (SEER), and Embase, to find useful informations on biomarkers for breast cancer. This review summarizes the current databases which have been utilized for identification of biomarkers for breast cancer. The information provided by this review would be beneficial to seeking appropriate strategies for diagnosis and treatment of breast cancer.

Pluripotency transcription factors in lung cancer-a review

Lung cancer is the leading cause of cancer-related mortality worldwide. Diagnosis of lung cancer in an early stage is still a challenge due to the asymptomatic course of early stages of the disease and the lack of a standard screening program for the population. Nowadays, learning about the mechanisms that lead to cancerogenesis in the lung is crucial for the development of new diagnostic and therapeutic strategies. Recently, many studies have proved that cancer stem cells (CSCs) are responsible for the initiation, progression, metastasis, recurrence, and even resistance of chemo- and radiotherapeutic treatment in patients with lung cancer. The expression of pluripotency transcription factors is responsible for stemness properties. In this review, we summarize the current knowledge on the role of CSCs and pluripotency transcription factors in lung carcinogenesis.