BRMS1 Expression Research Articles

Anti-metastatic Effects of Bee Venom and Melittin in Breast Cancer Cells by Upregulation of BRMS1 and DRG1 Genes.

Apitherapy has started to gain tremendous recognition because of extraordinary pharmacological importance of honeybee-related ingredients and their derivatives. There has been a renewed interest in the bee venom-based therapies. Interdisciplinary researchers are studying the chemistry and translational value of venom for effective cancer treatment. Bee venom and its major component, melittin, are cytotoxic in cancer cells. In this study, MTT and scratch assays were performed for analysis of melittin-mediated antimetastatic effects. QPCR was used for expression profiling of metastasis-related genes. Three anti-metastatic genes (BRMS1, DRG1, and KAI1/CD82) were studied for the first time after bee venom and melittin treatment in MDA-MB-231 breast cancer cells compared with normal breast cells, and two prometastatic genes (EGFR and WNT7B) were also examined. KAI1/CD82 and BRMS1 are the negative regulators of EGFR. WNT7B is a negative regulator of KAI1/CD82. Selective cytotoxicity of bee venom and melittin was found to be higher as compared to cisplatin. Melittin induced an increase in the expression of BRMS1 and DRG1, whereas bee venom upregulated DRG1 and KAI1/CD82 expression in breast cancer. WNT7B was downregulated in bee venom-treated breast cancer cells. Results suggested that bee venom/melittin exerted antimetastatic effects primarily through upregulation of BRMS1, DRG1, and KAI1/CD82, and downregulation of WNT7B.

Exploring the prognostic value of BRMS1 + microglia based on single-cell anoikis regulator patterns in the immunologic microenvironment of GBM

BackgroundAnoikis is a specialized form of programmed cell death induced by the loss of cell adhesion to the extracellular matrix (ECM). Acquisition of anoikis resistance is a significant marker for cancer cell invasion, metastasis, therapy resistance, and recurrence. Although current research has identified multiple factors that regulate anoikis resistance, the pathological mechanisms of anoikis-mediated tumor microenvironment (TME) in glioblastoma (GBM) remain largely unexplored.MethodsUtilizing single-cell RNA sequencing (scRNA-seq) data and employing non-negative matrix factorization (NMF), we identified and characterized TME cell clusters with distinct anoikis-associated gene signatures. Prognostic and therapeutic response analyses were conducted using TCGA and CGGA datasets to assess the clinical significance of different TME cell clusters. The spatial relationship between BRMS1 + microglia and tumor cells was inferred from spatial transcriptome RNA sequencing (stRNA-seq) data. To simulate the tumor immune microenvironment, co-culture experiments were performed with microglia (HMC3) and GBM cells (U118/U251), and microglia were transfected with a BRMS1 overexpression lentivirus. Western blot or ELISA were used to detect BRMS1, M2 macrophage-specific markers, PI3K/AKT signaling proteins, and apoptosis-related proteins. The proliferation and apoptosis capabilities of tumor cells were evaluated using CCK-8, colony formation, and apoptosis assays, while the invasive and migratory abilities of tumor cells were assessed using Transwell assays.ResultsNMF-based analysis successfully identified CD8 + T cell and microglia cell clusters with distinct gene signature characteristics. Trajectory analysis, cell communication, and gene regulatory network analyses collectively indicated that anoikis-mediated TME cell clusters can influence tumor cell development through various mechanisms. Notably, BRMS1 + AP-Mic exhibited an M2 macrophage phenotype and had significant cell communication with malignant cells. Moreover, high expression of BRMS1 + AP-Mic in TCGA and CGGA datasets was associated with poorer survival outcomes, indicating its detrimental impact on immunotherapy. Upregulation of BRMS1 in microglia may lead to M2 macrophage polarization, activate the PI3K/AKT signaling pathway through SPP1/CD44-mediated cell interactions, inhibit tumor cell apoptosis, and promote tumor proliferation and invasion.ConclusionThis pioneering study used NMF-based analysis to reveal the important predictive value of anoikis-regulated TME in GBM for prognosis and immunotherapeutic response. BRMS1 + microglial cells provide a new perspective for a deeper understanding of the immunosuppressive microenvironment of GBM and could serve as a potential therapeutic target in the future.

Abstract 6596: BRMS1 downregulation alters the tumor microenvironment and induces immunotherapy resistance in lung adenocarcinoma

Abstract Background: Lung cancer is the leading cause of cancer-related deaths globally. During cancer progression, tumor cells interact with tumor-infiltrating immune cells (TIICs) creating an immunosuppressive microenvironment. Therefore, it is essential to delineate the communication dynamics between cancer cells and TIICs to identify novel pathways for therapeutic targeting. BRMS1 is a metastasis suppressor gene that is frequently downregulated in lung adenocarcinoma (LUAD). We, and others, have shown that loss of BRMS1 results in increased distant metastatic disease. Given the strong correlation between immune suppression, metastasis, and immunotherapy resistance we sought to elucidate if BRMS1 contributes to these processes. Specifically, we hypothesized that loss of BRMS1 in LUAD cells influences the immune cell composition, shaping an immunosuppressive microenvironment and decreasing tumor response to immunotherapy. Methods: To experimentally address our hypothesis, we generated KrasG12D P53fl/fl Brms1−/− mice inducing spontaneous tumors with Ad-Cre intratracheal inoculation. RNA-seq scRNA-seq on Brms1+/+ and Brms1−/− tumors, coupled with cell type annotations using mMCP-counter and DCATS were used to identify diverse TIIC subsets. To validate our observation, we performed immunofluorescence and flow cytometry to assess the number of TIICs. To explore the impact of Brms1 loss on the efficacy of anti-PD1 immunotherapy, a syngeneic CMT167 mouse model with BRMS1KD cells implanted in the flank was treated with an anti-PD1 antibody. Results: Differential gene expression analysis of RNA-seq data revealed a reduction in CCL9, CCL24, CLEC1B, PYCARD and other proinflammatory molecules in Brms1−/− tumors. Gene ontology and GSEA highlighted a diminished immune response signature in Brms1−/- tumors. In contrast, hallmark gene sets like IFNγ response, IL6 signaling, and inflammation are highly enriched in Brms1+/+ tumors. mMCP-counter suggested a decrease in CD8+ T cells in Brms1−/- tumors. Likewise, scRNA-seq data confirmed a significant decrease in cytotoxic CD8+ T cells in the Brms1−/− mice. Immunofluorescence and flow cytometric analysis showed a reduction in cytotoxic CD8+ T cells with low proliferative potential (Ki67+) in the Brms1−/− mice. Postmortem on our syngeneic mouse tumors after a 30-day anti-PD1 antibody treatment revealed a significantly larger mean tumor size in the BRMS1KD group compared to the WT group (942.4 mm³ vs. 184 mm³; p<0.023). Immunophenotyping on these tumors using flow cytometry also demonstrated reduced cytotoxic CD8+ T cells in the KD group post-treatment. Conclusion: Our data suggest that reduced BRMS1 expression in LUAD alters CD8+ T cell composition and primary tumor response to immunotherapy. Implications of our findings underscore the potential of BRMS1 as a therapeutic target in the context of immunotherapy-resistant LUAD. Citation Format: Manendra B. Lankadasari, Yuan Liu, Brooke Mastrogiacomo, Yingjie Zhu, Elizabeth G. Dunne, Cameron N. Fick, Choudhary Harsha, Jorge S. Reis-Filho, David R. Jones. BRMS1 downregulation alters the tumor microenvironment and induces immunotherapy resistance in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6596.

BRMS1 in Gliomas-An Expression Analysis.

The metastatic suppressor BRMS1 interacts with critical steps of the metastatic cascade in many cancer entities. As gliomas rarely metastasize, BRMS1 has mainly been neglected in glioma research. However, its interaction partners, such as NFκB, VEGF, or MMPs, are old acquaintances in neurooncology. The steps regulated by BRMS1, such as invasion, migration, and apoptosis, are commonly dysregulated in gliomas. Therefore, BRMS1 shows potential as a regulator of glioma behavior. By bioinformatic analysis, in addition to our cohort of 118 specimens, we determined BRMS1 mRNA and protein expression as well as its correlation with the clinical course in astrocytomas IDH mutant, CNS WHO grade 2/3, and glioblastoma IDH wild-type, CNS WHO grade 4. Interestingly, we found BRMS1 protein expression to be significantly decreased in the aforementioned gliomas, while BRMS1 mRNA appeared to be overexpressed throughout. This dysregulation was independent of patients' characteristics or survival. The protein and mRNA expression differences cannot be finally explained at this stage. However, they suggest a post-transcriptional dysregulation that has been previously described in other cancer entities. Our analyses present the first data on BRMS1 expression in gliomas that can provide a starting point for further investigations.

Abstract 3142: BRMS1 alters the tumor inflammatory signature and immune infiltration in lung adenocarcinoma

Abstract Background: Lung adenocarcinoma (LUAD) is the leading cause of cancer-related deaths. Metastatic cancer is highly fatal which contributes to at least 90% of cancer-associated morbidities and mortalities. During metastasis, tumor cells alter their signaling cascade and interact with the immune cells in the tumor microenvironment Therefore, it is necessary to characterize and understand how these cancer cells influence tumor-infiltrating immune cells to facilitate and even enhance their ability to metastasize. BRMS1 is a metastasis suppressor gene which is frequently downregulated in LUAD. We, and others, have shown that loss of BRMS1 results in distant metastatic disease. Given the strong correlation between immune suppression, metastasis, and therapy resistance we sought to elucidate if BRMS1 contributes to these processes. Specifically, we hypothesized that LUAD cells downregulate BRMS1 which influences the immune cell composition in the tumor. This creates an immune-suppressive tumor microenvironment aiding in metastasis. Methods: To test our hypothesis, we generated KrasG12D P53fl/fl Brms1-/- mice which spontaneously develop tumors with Ad-Cre intratracheal inoculation. To elucidate the role of BRMS1 in the context of cancer, we performed RNA sequencing on tumors from Brms1 wild type and knockout background. We used MCP counter, an in silico cellular deconvolution algorithm on our bulk RNA seq data to identify various subsets of tumor-infiltrating immune cells. Furthermore, our observations were validated by immunofluorescence and flow cytometry. Results: Differential gene expression analysis using RNA seq data revealed a reduction in CXCL9, CCL5, CLEC1B, CCL9, CCL7 and other proinflammatory molecules in the Brms1-/- tumors. Gene ontology and gene set enrichment analysis highlighted a diminished immune response signature in Brms1-/- tumors. Hallmarks like interferon and IL6 signaling, complement and inflammation are highly enriched in Brms1+/+ tumors. MCP counter also suggested a significant increase in NK cells and reduction in CD8+ T cell population in the Brms1-/- tumors. To validate our observation, we performed immunofluorescence and flow cytometry to assess the number of infiltrating immune cells in the tumor microenvironment. Immunofluorescence data showed reduced cytotoxic T cells (CD8+ T cells) in Brms1-/- mice. The flow cytometric analysis also revealed a reduction in the proliferative potential of these CD8+ T cells along with the increased presence of myeloid-derived suppressor cells in the Brms1-/- mice. Conclusion: Our data suggest for the first time that reduced BRMS1 expression which is generally observed in multiple tumors not only influences metastasis but also alters tumor-infiltrating immune cell composition. Thus, BRMS1 downregulation presents as one of the potential immune evasion mechanisms that could be targeted for an improved therapy outcome in LAUD. Citation Format: Manendra B. Lankadasari, Yuan Liu, Di He, Samhita Bapat, Brooke Mastrogiacomo, Harry B. Lengel, David R. Jones. BRMS1 alters the tumor inflammatory signature and immune infiltration in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3142.

Metastasis Inhibition by Cell Type Specific Expression of BRMS1 Gene under The Regulation of miR200 Family Response Elements.

ObjectiveSpecific expression of therapeutic genes in cancer therapy has been per used for many years. One of the innovative strategies that have recently been introduced is employing miRNA response elements (MREs) of microRNAs (whose expression are reduced or inhibited in cancerous cells) into the 3´UTR of the therapeutic genes for their specific expression. Accordingly, MREs of anti-metastatic miRNA family have been used in 3´UTR of the metastasis suppressor gene in the corresponding cells to evaluate the level of metastatic behavior.Material and MethodsIn this experimental study, 3´UTR of the ZEB1 gene with 592 bp length, encompassing multiple MREs of miR-141, miR-429, miR-200b and miR-200c, was employed to replace BRMS1 3´UTR. The obtained vector was then assessed in the context of MCF-10A, MDA-MB231 and MCF-7 cells.ResultsIt was shown that the employed MREs are able to up-regulate BRMS expression in the metastatic MDA- MB231 cells (almost 3.5-fold increase), while it was significantly reduced within tumorigenic/non-metastatic MCF-7 cells. Specific expression of BRMS1 in metastatic cells led to a significant reduction in their migratory and invasive characteristics (about 65% and 55%, respectively). Two-tailed student’s t test was utilized for statistical analysis.ConclusionIt was demonstrated that a chimeric vector containing BRMS1 which is regulated by miR-200 family response element may represent a promising therapeutic tool. This is due to the capability of the chimeric vector for cell type-specific expression of anti-metastatic genes with lowest side-effects. It consequently prohibits the invasive characteristics of metastatic cells.

BRMS1 downregulation is a poor prognostic biomarker in anaplastic thyroid carcinoma patients.

BackgroundAnaplastic thyroid carcinoma (ATC) is the most aggressive cancer in humans with no optimal treatment strategy available. The molecular mechanisms of ATC remain unclear. The aim of this study was to investigate the prognostic value and role of BRMS1 in the progression of ATC.MethodsBRMS1 expression was examined in thyroid cell lines using Western blot analysis. Immunohistochemistry was also performed to assess BRMS1 expression in ATC and papillary thyroid cancer (PTC) tissue. Cell proliferation assays, colony formation analysis, cell migration assays, cell apoptosis analysis, and animal studies were used to examine the effects of BRMS1 expression on ATC progression.ResultsThe expression of BRMS1 was significantly lower in ATC than in PTC and was associated with poor prognosis in ATC patients. Downregulation of BRMS1 expression promoted the proliferation and migration of 8505C cells and decreased their expression of CX43. Over-expressed BRMS1 promoted the apoptosis and impaired the proliferation and migration of CAL-62 cells via upregulated CX43. In vivo, BRMS1 significantly promoted apoptosis and impaired cell proliferation.ConclusionTaken together, these findings demonstrate that decreased expression of BRMS1 is a poor prognostic biomarker in ATC patients. BRMS1 significantly promoted apoptosis and impaired cell proliferation via CX43 and P53. Loss of BRMS1 expression is therefore, one of the key pathomechanisms in ATC.

Identification of mRNAs related to endometrium function regulated by lncRNA CD36\u2013005 in rat endometrial stromal cells

BackgroundPolycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder in women of reproductive age and is commonly complicated by adverse endometrial outcomes. Long non-coding RNAs (lncRNAs) are a class of non-protein-coding transcripts that are more than 200 nucleotides in length. Accumulating evidence indicates that lncRNAs are involved in the development of various human diseases. Among these lncRNAs, lncRNA CD36–005 (CD36–005) is indicated to be associated with the pathogenesis of PCOS. However, the mechanisms of action of CD36–005 have not yet been elucidated.MethodsThis study determined the CD36–005 expression level in the uteri of PCOS rat model and its effect on the proliferation activity of rat primary endometrial stromal cells. RNA sequencing (RNA-seq) and bioinformatics analysis were performed to detect the mRNA expression profiles and the biological pathways in which these differentially expressed mRNAs involved, after CD36–005 overexpression in the primary endometrial stromal cells. The differential expression of Hmgn5, Nr5a2, Dll4, Entpd1, Fam50a, and Brms1 were further validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR).ResultsCD36–005 is highly expressed in the uteri of PCOS rat model and promotes the proliferation of rat primary endometrial stromal cells. A total of fifty-five mRNAs differentially expressed were identified in CD36–005 overexpressed stromal cells. Further analyses identified that these differentially expressed mRNAs participate in many biological processes and are associated with various human diseases. The results of qRT-PCR validation were consistent with the RNA-seq data.ConclusionsThese data provide a list of potential target mRNA genes of CD36–005 in endometrial stromal cells and laid a foundation for further studies on the molecular function and mechanism of CD36–005 in the endometrium.

VSP-17, a New PPARγ Agonist, Suppresses the Metastasis of Triple-Negative Breast Cancer via Upregulating the Expression of E-Cadherin.

Triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer, shows higher metastases and relapse rates than other subtypes. The metastasis of TNBC is the main reason for the death of TNBC patients. Increasing evidence has shown that inhibiting the metastasis of TNBC is a good method for TNBC treatment. Here, VSP-17 was designed and synthesized as an agonist of PPARγ, evidenced by upregulating the expression of CD36 and increasing the activity of PPARγ reporter gene. VSP-17 obviously inhibited the migration and invasion process of MDA-MB-231 cells but showed little effect on the viability of MDA-MB-231 cells. Notably, VSP-17 could selectively promote the expression of E-cadherin without affecting the expression of BRMS1, CXCL12, MMP9, Orai1, Stim1, TGF-β, and VEGF. In addition, VSP-17 significantly suppressed the metastasis of liver and promoted the expression of E-cadherin in MDA-MB-231 xenograft model. In conclusion, VSP-17 inhibited the metastasis process of TNBC via upregulating the expression of E-cadherin.

Do BRCA 1 mutations affect selected molecular variables in women with breast and ovarian cancer carrying cerebral metastases?

e13017 Background: Cerebral metastases develop in 10-30% of patients with breast cancer and in around 3.3 to 4% of patients with ovarian cancer. The present study evaluates the expression of ER alpha and beta receptors, PR, HER2 and markers associated with metastases: stromal cell-derived factor-1 (SDF1) and its receptor CXCR4, breast cancer metastasis suppressor (BRMS1), astrocyte elevated gene (AEG-1), depending on the status of BRCA1 protein in cancerous cells of the patients (somatic mutation). Methods: The material originated from 30 women with breast cancer and 22 patients with ovarian cancer in whom cerebral metastases were detected. The studies were conducted on paraffin block sections, the markers were detected using immunocytochemistry, employing specific antibodies. Results: In the breast cancer group, BRCA 1 protein expression was detected in 11 patients, absence of the protein in 19. No significant differences were disclosed in the grade of ER, PR, HER2, SDF1, CXCR4, BRMS1 or AG-1 expression which would be dependent on the status of BRCA1. Expression of the proteins failed to correlate with patients' age, clinical advancement at diagnosis, presence of metastases to lymph nodes. Patients with no PR expression significantly more frequently manifested high expression of CXCR4 (p = 0.0436). The ovarian cancer group included 7 patients with expression of BRCA1 protein, absence of such expression was recorded in 15 patients. No statistically significant differences were disclosed in the expression of the studied factors which would be related to the status of BRCA1 in cancer cells. Also, no differences were detected in the expression of the studied factors which would depend on the patient’s age, primary advancement of the disease or histological type of the cancer. Conclusions: Among numerous molecular factors examined in women with breast or ovarian cancer no statistically significant differences were detected which would depend on BRCA1 protein status in cancer cells. The absence of PR expression in women with breast cancer was associated with high expression of CXCR4, which might indicate that PR-negative women with breast cancer exhibit higher metastatic potential.

Expression of SOCS1 and CXCL12 Proteins in Primary Breast Cancer Are Associated with Presence of Circulating Tumor Cells in Peripheral Blood

Circulating tumor cells (CTCs) are independent prognostic factors in the primary and metastatic breast cancer patients and play crucial role in hematogenous tumor dissemination. The aim of this study was to correlate the presence of CTCs in peripheral blood with the expression of proteins in tumor tissue that have a putative role in regulation of cell growth and metastatic potential. This prospective study included 203 primary breast cancer patients treated by definitive surgery. CTCs were detected by quantitative real-time PCR for the expression of epithelial (CK19) or epithelial-to-mesenchymal transition–inducing transcription factor genes (TWIST1, SNAIL1, SLUG, and ZEB1). Expression of APC, ADAM23, CXCL12, E-cadherin, RASSF1, SYK, TIMP3, BRMS1, and SOCS1 proteins in primary breast tumor tissue was evaluated by immunohistochemistry. CTCs with epithelial markers were found in 17 (9.2%) patients. Their occurrence was associated with inhibition of SOCS1 expression (odds ratio [OR] = 0.07; 95% confidence interval [CI], 0.03-0.13; P < .001). CTCs with positive epithelial-to-mesenchymal transition markers were detected in 30 (15.8%) patients; however, no association with analyzed protein expressions was found. Overall, CTCs were detected in 44 (22.9%) patients. Presence of any CTC marker was significantly associated with positive CXCL12 expression (OR = 3.08; 95% CI, 1.15-8.26; P = .025) and lack of SOCS1 expression (OR = 0.10; 95% CI, 0.04-0.25; P < .001) in patient’s tumor tissues. As both CXCL12 and SOCS1 proteins are involved in cytokine signaling, our results provide support for the hypothesis that aberrant signaling cross talk between cytokine and chemokine responses could have an important role in hematogenous dissemination of tumor cells in breast cancer.

Effect of BRMS1 expression on proliferation, migration and adhesion of mouse forestomach carcinoma.

To discuss the effect of BRMS1 on the proliferation, migration and adhesion of mouse forestomach carcinoma. The constructed pCMV-myc-BRMS1 recombinant plasmid and blank plasmid were transfected into mouse forestomach carcinoma. MTT method was employed to measure the activity of gastric cancer cell; the scratch assay and Transwell assay to measure the migration and invasion of gastric cancer cell; the adhesion assay to measure the adhesion of gastric cancer cell; while the Western blot assay to measure the expression of The NF-κB signal pathway, downstream matrix metalloproteinase (MMP)-2, MMP-9 and osteopontin and E-cadherin in the gastric cancer cell. Besides, the transplanted animal model of gastric cancer in mice was constructed to measure the size of tumor xenograft. Results of MTT assay showed that, compared with the empty vector control group, the activity of gastric cancer cell was not affected in the BRMS1 transfection group. The improved expression of BRMS1 could inhibit the adhesion, migration and invasion of gastric cancer cell (P<0.01). Besides, compared with the empty vector control group, the phosphorylation of NF-κB p65 and IκBα was reduced in the BRMS1 transfection group, with the decreased expression of MMP-2, MMP-9 and osteopontin and the increased expression of E-cadherin (P<0.01). Results of animal experiment also showed that the expression of BRMS1 did not affect the transplanted tumor. The expression of BRMS1 can significantly inhibit the adhesion, migration, invasion and metastasis of mouse forestomach carcinoma gastric cancer cell, which is related to The NF-κB signal pathway.

Histone demethylase JARID1C promotes breast cancer metastasis cells via down regulating BRMS1 expression

Metastasis is the leading cause of death in breast cancer patients. However, until now, the mechanisms of breast cancer metastasis remain elusive. Epigenetic switch, including histone methylation or demethylation, which can either activates or represses transcription. The JARID1C is a histone demethylase that promotes cancer cell growth and is involved in transcriptional regulation and chromatin remodeling, cause X-linked mental retardation. But the pathogenic breadth and mechanistic aspects of this effect relative to breast cancer have not been defined. In this study, we aimed to investigate the role of JARID1C in breast cancer. In clinical breast cancer samples, we found that JARID1C expression was significantly upregulated in cancer lesions compared with paired normal breast tissues and its expression level is positively correlated with metastasis. Silencing JARID1C in breast cancer cells could inhibit cell migration and invasion. Moreover, we also found that the expression of BRMS1 was modulated by JARID1C. Silencing of JARID1C dramatically increased BRMS1 expression both at mRNA and protein level. Mechanistically, we found JARID1C exerts its function through modulation of H3K4me3 at the BRMS1 gene promoter, which was associated with inactive BRMS1 transcription. BRMS1 knockdown reversed shJARID1C-induced migration inhibition. Further, BRMS1 expression in human breast cancer is negatively correlated with JARID1C expression. Our results, for the first time, portray a pivotal role of JARID1C in regulating metastatic behaviors of breast cancer cells.

Breast Cancer Metastasis Suppressor-1 Promoter Methylation in Primary Breast Tumors and Corresponding Circulating Tumor Cells

Breast cancer metastasis suppressor-1 (BRMS1) differentially regulates the expression of multiple genes, leading to metastasis suppression without affecting orthotopic tumor growth. For the first time, BRMS1 promoter methylation was evaluated as a prognostic biomarker in primary breast tumors and a subset of corresponding circulating tumor cells (CTC). Formalin-fixed paraffin embedded samples were analyzed for BRMS1 methylation status using methylation-specific PCR in a human specimen cohort consisting of noncancerous tissues, benign fibroadenomas, and primary breast tumors, including some with adjacent noncancerous tissues. Peripheral blood mononuclear cells from a large subset of these patients were fixed in cytospins and analyzed. In addition, BRMS1 expression in cytospins was examined by double-immunofluorescence using anti-BRMS1 and pan-cytokeratin antibodies. BRMS1 promoter methylation was not detected in noncancerous breast tissues or benign fibroadenomas; however, methylation was observed in more than a third of primary breast tumors. Critically, BRMS1 promoter methylation in primary tumors was significantly associated with reduced disease-free survival with a trend toward reduced overall survival. Similarly, a third of cytospin samples were positive for the presence of CTCs, and the total number of detected CTCs was 41. Although a large fraction of CTCs were negative or maintained low expression of BRSM1, promoter methylation was observed in a small fraction of samples, implying that BRSM1 expression in CTCs was either downregulated or heterogeneous. In summary, these data define BRMS1 promoter methylation in primary breast tumors and associated CTCs. This study indicates that BRSM1 promoter methylation status has biomarker potential in breast cancer.

Low BRMS1 expression promotes nasopharyngeal carcinoma metastasis in vitro and in vivo and is associated with poor patient survival

BackgroundBreast cancer metastasis suppressor 1 (BRMS1) is a metastasis suppressor gene. This study aimed to investigate the impact of BRMS1 on metastasis in nasopharyngeal carcinoma (NPC) and to evaluate the prognostic significance of BRMS1 in NPC patients.MethodsBRMS1 expression was examined in NPC cell lines using quantitative reverse transcription-polymerase chain reaction and Western blotting. NPC cells stably expressing BRMS1 were used to perform wound healing and invasion assays in vitro and a murine xenograft assay in vivo. Immunohistochemical staining was performed in 274 paraffin-embedded NPC specimens divided into a training set (n = 120) and a testing set (n = 154).ResultsBRMS1 expression was down-regulated in NPC cell lines. Overexpression of BRMS1 significantly reversed the metastatic phenotype of NPC cells in vitro and in vivo. Importantly, low BRMS1 expression was associated with poor distant metastasis-free survival (DMFS, P < 0.001) and poor overall survival (OS, P < 0.001) in the training set; these results were validated in the testing set and overall patient population. Cox regression analysis demonstrated that low BRMS1 expression was an independent prognostic factor for DMFS and OS in NPC.ConclusionsLow expression of the metastasis suppressor BRMS1 may be an independent prognostic factor for poor prognosis in NPC patients.

Abstract 3416: Ubiquitous Brms1 expression is critical for mammary carcinoma metastasis suppression via promotion of apoptosis

Abstract Morbidity and mortality in breast cancer patients are drastically increased when primary tumor cells are able to spread to distant sites and proliferate to become secondary lesions. Effective treatment of metastatic disease has been limited; therefore, increased molecular understanding to identify biomarkers and targets is needed. We have previously shown that breast cancer metastasis suppressor 1 (Brms1) can suppress development of pulmonary metastases when expressed in a variety of cancer types, including metastatic mammary carcinoma. Our lab has developed two transgenic Brms1 mouse models, one which expresses murine Brms1 cDNA specifically in mammary tissue (expression by the mouse mammary tumor virus (MMTV) promoter) and a ubiquitous Brms1 expression model (expression by the chicken beta actin promoter). The goal of this study was to investigate mechanisms of Brms1-mediated metastasis suppression in transgenic mice that express Brms1 using a polyoma middle T (PyMT) oncogene-induced model. Brms1 expression, either ubiquitously or predominantly in the mammary gland, did not significantly alter growth of the primary tumor, confirming earlier studies. When expressed ubiquitously, Brms1 suppressed pulmonary metastasis and promoted tumor cell apoptosis in the lung but not in the mammary gland. However, selective expression of Brms1 in the mammary gland using the MMTV promoter did not significantly block metastasis nor did it promote apoptosis in mammary glands or lungs despite increased expression within primary tumors and the lungs. These results suggest tissue- or cell-type specific expression of Brms1 is a critical determinant for Brms1-mediated metastasis suppression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3416. doi:1538-7445.AM2012-3416

Cytoplasmic BRMS1 expression in malignant melanoma is associated with increased disease-free survival

Background/aimsBreast cancer metastasis suppressor 1 (BRMS1) blocks metastasis in melanoma xenografts; however, its usefulness as a biomarker in human melanomas has not been widely studied. The goal was to measure BRMS1 expression in benign nevi, primary and metastatic melanomas and evaluate its impact on disease progression and prognosis.MethodsParaffin-embedded tissue from 155 primary melanomas, 69 metastases and 15 nevi was examined for BRMS1 expression using immunohistochemistry. siRNA mediated BRMS1 down-regulation was used to study impact on invasion and migration in melanoma cell lines.ResultsA significantly higher percentage of nevi (87%), compared to primary melanomas (20%) and metastases (48%), expressed BRMS1 in the nucelus (p < 0.0001). Strong nuclear staining intensity was observed in 67% of nevi, and in 9% and 24% of the primary and metastatic melanomas, respectively (p < 0.0001). Comparable cytoplasmic expression was observed (nevi; 87%, primaries; 86%, metastases; 72%). However, a decline in cytoplasmic staining intensity was observed in metastases compared to nevi and primary tumors (26%, 47%, and 58%, respectively, p < 0.0001). Score index (percentage immunopositive celles multiplied with staining intensity) revealed that high cytoplasmic score index (≥ 4) was associated with thinner tumors (p = 0.04), lack of ulceration (p = 0.02) and increased disease-free survival (p = 0.036). When intensity and percentage BRMS1 positive cells were analyzed separately, intensity remained associated with tumor thickness (p = 0.024) and ulceration (p = 0.004) but was inversely associated with expression of proliferation markers (cyclin D3 (p = 0.008), cyclin A (p = 0.007), and p21Waf1/Cip1 (p = 0.009)). Cytoplasmic score index was inversely associated with nuclear p-Akt (p = 0.013) and positively associated with cytoplasmic p-ERK1/2 expression (p = 0.033). Nuclear BRMS1 expression in ≥ 10% of primary melanoma cells was associated with thicker tumors (p = 0.016) and decreased relapse-free period (p = 0.043). Nuclear BRMS1 was associated with expression of fatty acid binding protein 7 (FABP7; p = 0.011), a marker of invasion in melanomas. In line with this, repression of BRMS1 expression reduced the ability of melanoma cells to migrate and invade in vitro.ConclusionOur data suggest that BRMS1 is localized in cytoplasm and nucleus of melanocytic cells and that cellular localization determines its in vivo effect. We hypothesize that cytoplasmic BRMS1 restricts melanoma progression while nuclear BRMS1 possibly promotes melanoma cell invasion.Please see related article: http://www.biomedcentral.com/1741-7015/10/19

Location, location, location: the BRMS1 protein and melanoma progression

The metastasis suppressor, BRMS1, has been demonstrated to cause dramatic regression of metastatic lesions without blocking orthotopic tumor growth. The role of BRMS1 is well-documented for several non-melanoma malignancies, such as breast cancer, ovarian cancer and non-small-cell lung cancer. However, its role in melanoma is just beginning to be understood, with a recent article by Slipicevic et al. highlighting the levels of expression of BRMS1 in benign nevi, primary and metastatic melanoma samples. Their findings emphasize that the intracellular location of BRMS1 protein (cytoplasmic or nuclear), appears to have a significant impact upon the metastatic capacity of melanoma cells. Interestingly, this selective localization translates into a statistically significant decrease in the relapse-free period in melanoma patients, further associated with a thicker Breslow's depth of primary melanomas. However, and more importantly, this study begins to define a clearer role for BRMS1 in melanoma that is strictly dependent upon its cellular location, with nuclear expression associated with invasive and metastatic capacity and cytoplasmic expression resulting in repressive effects upon progression and metastasis.Please see related article: http://www.biomedcentral.com/1471-2407/12/73

Location, location, location: the BRMS1 protein and melanoma progression

The metastasis suppressor, BRMS1, has been demonstrated to cause dramatic regression of metastatic lesions without blocking orthotopic tumor growth. The role of BRMS1 is well-documented for several non-melanoma malignancies, such as breast cancer, ovarian cancer and non-small-cell lung cancer. However, its role in melanoma is just beginning to be understood, with a recent article by Slipicevic et al. highlighting the levels of expression of BRMS1 in benign nevi, primary and metastatic melanoma samples. Their findings emphasize that the intracellular location of BRMS1 protein (cytoplasmic or nuclear), appears to have a significant impact upon the metastatic capacity of melanoma cells. Interestingly, this selective localization translates into a statistically significant decrease in the relapse-free period in melanoma patients, further associated with a thicker Breslow's depth of primary melanomas. However, and more importantly, this study begins to define a clearer role for BRMS1 in melanoma that is strictly dependent upon its cellular location, with nuclear expression associated with invasive and metastatic capacity and cytoplasmic expression resulting in repressive effects upon progression and metastasis.

Ubiquitous Brms1 expression is critical for mammary carcinoma metastasis suppression via promotion of apoptosis.

Morbidity and mortality of breast cancer patients are drastically increased when primary tumor cells are able to spread to distant sites and proliferate to become secondary lesions. Effective treatment of metastatic disease has been limited; therefore, an increased molecular understanding to identify biomarkers and therapeutic targets is needed. Breast cancer metastasis suppressor 1 (BRMS1) suppresses development of pulmonary metastases when expressed in a variety of cancer types, including metastatic mammary carcinoma. Little is known of Brms1 function throughout the initiation and progression of mammary carcinoma. The goal of this study was to investigate mechanisms of Brms1-mediated metastasis suppression in transgenic mice that express Brms1 using polyoma middle T oncogene-induced models. Brms1 expression did not significantly alter growth of the primary tumors. When expressed ubiquitously using a β-actin promoter, Brms1 suppressed pulmonary metastasis and promoted apoptosis of tumor cells located in the lungs but not in the mammary glands. Surprisingly, selective expression of Brms1 in the mammary gland using the MMTV promoter did not significantly block metastasis nor did it promote apoptosis in the mammary glands or lung, despite MMTV-induced expression within the lungs. These results strongly suggest that cell type-specific over-expression of Brms1 is important for Brms1-mediated metastasis suppression.