Bone morphogenetic proteins, breast cancer, and bone metastases: striking the right balance

Proteomic Analysis of Breast Cancer Subtypes Identifies Stromal Contributions that Dictate Aggressive Malignant Behavior

Breast cancer manifests as multiple subtypes with distinct patient outcomes and treatment strategies. Here, we optimized proteomic analysis of Formalin-Fixed Paraffin-Embedded (FFPE) specimens from patients diagnosed with five breast cancer subtypes, luminal A, luminal B, Her2, triple negative (TNBC) and metaplastic breast cancers (MBC), and from disease-free individuals undergoing reduction mammoplasty (RM). We identified and quantified ∼6,000 protein groups (with >2 peptides per protein) with significant changes in over 26% of proteins comparing each cancer subtype with control RM. Stringent statistical filters allowed us to deeply mine 576 significant conserved protein changes shared by all subtypes and protein changes unique to each subtype. The most aggressive subtype, MBC, revealed exacerbated stromal stress responses, as illustrated by a collagenolytic extracellular matrix (ECM) and immune participation biased towards neutrophils and eosinophils. Immunostaining of breast tissue sections confirmed differences across subtypes, in particular, a dramatic upregulation of SERPINH1, neutrophil-specific myeloperoxidase and eosinophil cationic protein in MBC. In summary, deep proteomic, digitalized protein abundance profiles, generated from FFPE breast cancer tissues, revealed significant changes in ECM and cellular proteins providing insight into clinically relevant states.

Implications of Mineralization Biomarkers in Breast Cancer Outcomes Beyond Calcifications

The aim of this work was to explore the biomarkers associated with epithelial to mesenchymal transition (EMT) and mineralization processes as new prognostic factors across different breast cancer phenotypes. To this end, 133 breast biopsies, including benign and malignant lesions, with or without microcalcifications, were retrospectively collected. Immunohistochemical analysis was performed to evaluate the expression of vimentin, BMP-2, BMP-4, RANKL, Runx2, OPN, PTX3, and SDF-1, while Kaplan-Meier plots were used to assess their prognostic impact on overall survival in a dataset of 2976 breast cancer patients. The expression of vimentin, BMP-2, BMP-4, and SDF-1 was significantly higher in malignant lesions compared to benign ones, regardless of the presence of microcalcifications. Notably, these markers showed no correlation with traditional prognostic factors, such as tumor grade or hormone receptor status. The bioinformatics analysis provided valuable insights into the possible prognostic and therapeutic significance of BMP-2, BMP-4, SDF-1, and vimentin in breast cancer. In fact, all these biomarkers impact on the overall survival in specific molecular breast cancer types. In addition, high expression of SDF-1 and vimentin is able to predict the response to chemotherapy. The findings here reported suggest that vimentin, BMP-2, BMP-4, and SDF-1 could be independent prognostic biomarkers in breast cancer, providing insights beyond traditional clinical factors.

BMP Stimulation Differentially Affects Phosphorylation and Protein Stability of β-Catenin in Breast Cancer Cell Lines

Increased expression and nuclear translocation of β-CATENIN is frequently observed in breast cancer, and it correlates with poor prognosis. Current treatment strategies targeting β-CATENIN are not as efficient as desired. Therefore, detailed understanding of β-CATENIN regulation is crucial. Bone morphogenetic proteins (BMP) and Wingless/Integrated (WNT) pathway crosstalk is well-studied for many cancer types including colorectal cancer, whereas it is still poorly understood for breast cancer. Analysis of breast cancer patient data revealed that BMP2 and BMP6 were significantly downregulated in tumors. Since mutation frequency in genes enhancing β-CATENIN protein stability is relatively low in breast cancer, we aimed to investigate whether decreased BMP ligand expression could contribute to a high protein level of β-CATENIN in breast cancer cells. We demonstrated that downstream of BMP stimulation, SMAD4 is required to reduce β-CATENIN protein stability through the phosphorylation in MCF7 and T47D cells. Consequently, BMP stimulation reduces β-CATENIN levels and prevents its nuclear translocation and target gene expression in MCF7 cells. Conversely, BMP stimulation has no effect on β-CATENIN phosphorylation or stability in MDA-MB-231 and MDA-MB-468 cells. Likewise, SMAD4 modulation does not alter the response of those cells, indicating that SMAD4 alone is insufficient for BMP-induced β-CATENIN phosphorylation. While our data suggest that considering BMP activity may serve as a prognostic marker for understanding β-CATENIN accumulation risk, further investigation is needed to elucidate the differential responsiveness of breast cancer cell lines.

Bioinformatics Analysis of the Genetic and Epigenetic Alterations of Bone Morphogenetic Protein Receptors in Metastatic Breast Cancer

The leading cause of mortality in patients with breast cancer is metastasis, and bone morphogenetic protein (BMP) signaling activation regulates metastasis in breast cancer. This study explored the genetic and epigenetic modification of BMP receptor genes associated with metastatic breast cancer cells using bioinformatics. The genetic and epigenetic alterations of BMP receptors (BMPR1A, BMPR1B, BMPR2, ACVR2A, ACVR1, ACVR2B, ACVR1B, HJV, and ENG) were examined using cBioportal and methSurv, respectively. mRNA expression was analyzed using TNM plot and bcgenex, and protein expression was studied using Human Protein Atlas. Prognostic value and ROC were investigated using Kaplan-Meier (KM) and ROC plot, respectively. Finally, mutant function was predicted using several databases, including PolyPhen-2, FATHMM, Mutation Assessor, and PredictSNP. Oncoprint analysis showed genetic alterations in BMPR1A (39%), BMPR1B (13%), BMPR2 (34%), ACVR2A (14%), ACVR1 (7%), ACVR2B (13), ACVR1B (35%), HJV (40%), and ENG (33%) across the patients with breast cancer in The Metastatic Breast Cancer Project. The mRNA and protein levels of BMPR2 were increased in metastatic breast tumor tissues compared with those in normal and breast tumor tissues. BMPR1A and BMPR2 showed the highest and lowest levels of epigenetic alterations among the BMP receptors, respectively. The patients with breast cancer who had low levels of BMPR2 had a better overall survival (OS) than those with high levels of BMPR2. Functional mutation prediction showed that mutants in BMPR2 (R272L, E274K, and L685F), ACVR2A (S127L), and ACVR1B (R484H), are deleterious, probably damaging, and possess a cancer phenotype. ROC plot revealed no BMP receptors correlated with endocrine therapy sensitivity. BMPR1B, BMPR2, and ACVR2A levels were significantly linked as moderate prediction of anti-HER2, BMPR2, and ACVR1B demonstrated moderate predictive potential for chemotherapy sensitivity. This study contributed in fully comprehending the significance of genetic and epigenetic alterations in BMP receptors and BMP signaling in metastatic breast cancer cells for the development of breast cancer treatment plans.

BMP6 inhibits gastric cancer growth and predicts good prognosis

BACKGROUND

Gastric cancer (GC) is a common tumors in the digestive tract, and effective treatment methods are still lacking. Bone morphogenetic protein 6 (BMP6) is closely related to the occurrence and development of various tumors, but its relevance to GC is still unclear. The aim of the study was to explore the relationship between BMP6 and the occurrence and development of GC.

METHODS

In this study, we investigated the relationship between BMP6 and the prognosis of GC patients using bioinformatics technology and clinical tissue samples. We also explored the connection between BMP6 and the biological behavior of GC cells through molecular biology experiments and relevant in vivo animal experiments. Finally, we examined the mechanisms by which BMP6 inhibits the onset and progression of GC.

RESULTS

Through analysis of The Cancer Genomics Atlas (TCGA) database, we observed that BMP6 is expressed at low levels in GC, and its low expression is associated with a poor prognosis in GC patients. Cell experiments demonstrated that BMP6 expression can influence the proliferation of GC cells both in vitro and in vivo. Furthermore, we discovered that BMP6 is linked to the nuclear factor-κB (NF-κB) pathway, and subsequent experiments confirmed that BMP6 can inhibit the biological activity of GC cells by activating the NF-κB pathway.

CONCLUSIONS

Our findings suggest that BMP6 is a potential prognostic biomarker in GC and can regulate the biological activity of GC cells through the NF-κB pathway. BMP6 may serve as a promising therapeutic target for GC, and our study introduces novel ideas for the prevention and treatment of this disease.

Unique macrophage phenotypes activated by BMP signaling in breast cancer bone metastases

Metastatic breast cancer (mBC) tissue in bone was systematically profiled to define the composition of the tumor microenvironment. Gene expression identified a high myeloid signature of patients with improved survival outcomes. Bone metastases were profiled by spatial proteomics to examine myeloid populations within the stroma that correlated with macrophage functions. Single-cell spatial analysis uncovered macrophage activation in the stroma of mBC bone lesions. Matched BC patient samples of primary breast tumor and bone metastasis tissues were compared for gene expression in the bone, where bone morphogenetic protein 2 (BMP2) was most significantly upregulated. Immune cell changes from breast to bone demonstrated a loss of lymphoid cells but a consistent population of macrophages. BMP-activated macrophages were increased uniquely in bone. Bone marrow-derived macrophage activation coupled with BMP inhibition increased inflammatory responses. Using experimental mouse models of mBC bone metastasis and trained immunity, we found that BMP inhibition restricts progression of metastases early in the macrophage activation state but not after tumors were established in the bone. This study revealed unique myeloid BMP activation states that are distinctly integrated with bone metastases.

Evaluation of BMP-2 as a Differentiating and Radiosensitizing Agent for Colorectal Cancer Stem Cells

BACKGROUND

Despite effective clinical responses, a large proportion of patients undergo resistance to radiotherapy. The low response rate to current treatments in different stages of colorectal cancer depends on the prominent role of stem cells in cancer.

OBJECTIVE

In the present study, the role of BMP-2 as an ionizing radiation-sensitive factor in colorectal cancer cells was investigated.

METHODS

A sphere formation assay was used for the enrichment of HCT-116 cancer stem cells (CSCs). The effects of combination therapy (BMP-2+ radiation) on DNA damage response (DDR), proliferation, and apoptosis were evaluated in HCT-116 and CSCs. Gene expressions of CSCs and epithelialmesenchymal transition (EMT) markers were also evaluated.

RESULTS

We found that the sphere formation assay showed a significant increase in the percentage of CSCs. Moreover, expression of CSCs markers, EMT-related genes, and DNA repair proteins significantly decreased in HCT-116 cells compared to the CSCs group after radiation. In addition, BMP-2 promoted the radiosensitivity of HCT-116 cells by decreasing the survival rate of the treated cells at 2, 4, and 6 Gy compared to the control group in HCT-116 cells.

CONCLUSION

Our findings indicated that BMP-2 could affect numerous signaling pathways involved in radioresistance. Therefore, BMP-2 can be considered an appealing therapeutic target for the treatment of radioresistant human colorectal cancer.

Simvastatin prevents BMP-2 driven cell migration and invasion by suppressing oncogenic DNMT1 expression in breast cancer cells

Both epigenetic and genetic changes in the cancer genome act simultaneously to promote tumor development and metastasis. Aberrant DNA methylation, a prime epigenetic event, is often observed in various cancer types. The elevated DNA methyltransferase 1 (DNMT1) enzyme creates DNA hypermethylation at CpG islands to drive oncogenic potential. This study emphasized to decipher the molecular mechanism of endogenous regulation of DNMT1 expression for finding upstream signaling molecules. Cancer database analyses found an upregulated DNMT1 expression in most cancer types including breast cancer. Overexpression of DNMT1 showed an increased cell migration, invasion, and stemness potential whereas 5-azacytidine (DNMT1 inhibitor) and siRNA mediated knockdown of DNMT1 exhibited inhibition of such cancer activities in breast cancer MDA-MB-231 and MCF-7 cells. Infact, cancer database analyses further found a positive correlation of DNMT1 transcript with both cholesterol pathway regulatory genes and BMP signaling molecules. Experimental observations documented that the cholesterol-lowering drug, simvastatin decreased DNMT1 transcript as well as protein, whereas BMP-2 treatment increased DNMT1 expression in breast cancer cells. In addition, expression of various key cholesterol regulatory genes was found to be upregulated in response to BMP-2 treatment. Moreover, simvastatin inhibited BMP-2 induced DNMT1 expression in breast cancer cells. Thus, this study for the first time reveals that both BMP-2 signaling and cholesterol pathways could regulate endogenous DNMT1 expression in cancer cells.

Targeting c-Jun Is a Potential Therapy for Luminal Breast Cancer Bone Metastasis

Luminal breast cancer has the highest bone metastasis frequency among all breast cancer subtypes; however, its metastatic mechanism has not been elucidated because of a lack of appropriate models. We have previously developed useful bone metastatic cell lines of luminal breast cancer using MCF7 cells. In this study, we characterized bone metastatic MCF7-BM cell lines and identified c-Jun as a novel bone metastasis marker of luminal breast cancer. The protein level of c-Jun was upregulated in MCF7-BM cells compared with that in parental cells, and its deficiency resulted in the suppression of tumor cell migration, transformation, and reduced osteolytic ability. In vivo, dominant-negative c-Jun exhibited smaller bone metastatic lesions and a lower metastatic frequency. Histologic analysis revealed that c-Jun expression was heterogeneous in bone metastatic lesions, whereas c-Jun overexpression mediated a vicious cycle between MCF7-BM cells and osteoclasts by enhancing calcium-induced migration and releasing the osteoclast activator BMP5. Pharmacological inhibition of c-Jun by the Jun amino-terminal kinase (JNK) inhibitor JNK-IN-8 effectively suppressed tumorigenesis and bone metastasis in MCF7-BM cells. Furthermore, c-Jun downstream signals were specifically correlated with the clinical prognosis of patients with the luminal subtype of breast cancer. Our results illustrate the potential benefits of a therapy that targets c-Jun to prevent bone metastasis in luminal breast cancer.

IMPLICATIONS

c-Jun expression mediates bone metastasis in luminal breast cancer by forming a vicious cycle in the bone microenvironment, which reveals potential strategies for subtype-specific bone metastasis therapy.

BMP4 upregulates glycogen synthesis through the SMAD/SLC2A1 (GLUT1) signaling axis in hepatocellular carcinoma (HCC) cells

BACKGROUND

Excessive hepatic glycogen accumulation benefits tumorigenesis and cancer cell survival. We previously reported that BMP4 has the strongest ability to promote glycogenesis among the 14 BMPs in hepatocytes and augmented hepatocellular carcinoma (HCC) cell survival under hypoxia and hypoglycemia conditions by promoting the glycolysis pathway. However, the mechanism underlying BMP4's effect on glycogenesis in HCC remains elusive.

METHODS

The expression of BMP4 and SLC2A1 were acquired by analyzing the TCGA-LIHC dataset, as well as by immunohistochemical analysis of the 40 pairs of human HCC samples and para-tumor tissues. Gene expressions were detected by qPCR, immunoflurorescence staining, and Western blotting. Overexpression and silencing of BMP4 were accomplished through adenoviruses Ad-B4 and Ad-siB4 infection. Hepatic glycogen was detected by PAS staining. SLC2A1 (GLUT1) function was blocked by the inhibitor BAY-876. ChIP assay was used to determine the binding of SMADs to the promoter region of SLC2A1 in HCC cells. Lastly, the in vivo effect of BMP4-regulated SLC2A1 on HCC tumor growth was assessed in a xenograft model of HCC.

RESULTS

The elevated expression of BMP4 in HCC tumor tissues was highly correlated with hepatic glycogen accumulation in clinical samples. SLC2A1 was highly expressed in HCC tumor tissue and correlated with clinical stage and prognosis. Exogenous BMP4 augmented glycogen accumulation and upregulated the expression of glycogen synthesis-related genes in Huh7 and HepG2 cells, both of which were effectively blunted by SLC2A1inhibitor BAY-876. In mechanism, BMP4 activated SMAD5 to regulate the promoter of SLC2A1to enhance its expression. The in vivo xenograft experiments revealed that BMP4 promoted glycogen accumulation and tumor growth, which were effectively diminished by BAY-876.

CONCLUSION

These results demonstrate that BMP4 upregulates glycogen synthesis through the SMAD/SLC2A1 (GLUT1) signaling axis in HCC cells, which may be exploited as novel therapeutic targets for HCC treatment.

Aberrant expression of bone morphogenetic proteins in the disease progression and metastasis of breast cancer

Background

Bone morphogenetic proteins (BMPs) play crucial roles in the tumorigenesis and metastasis of cancers. Controversy remains about the exact implications of BMPs and their antagonists in breast cancer (BC), due to their diverse and complex biological functions and signalling. A comprehensive study of the whole family and their signalling in breast cancer is provoked.

Methods

Aberrant expression of BMP, BMP receptors and antagonists in primary tumours in breast cancer were analysed by using TCGA-BRCA and E-MTAB-6703 cohorts. Related biomarkers including ER, HER, proliferation, invasion, angiogenesis, lymphangiogenesis and bone metastasis were involved to identify the relationship with BMPs in breast cancer.

Results

The present study showed BMP8B was significantly increased in breast tumours, while BMP6 and ACVRL1 were decreased in breast cancer tissues. The expressions of BMP2, BMP6, TGFBR1 and GREM1 were significantly correlated with BC patients' poor overall survival. Aberrant expression of BMPs, together with BMP receptors, were explored in different subtypes of breast cancer according to ER, PR and HER2 status. Furthermore, higher levels of BMP2, BMP6 and GDF5 were revealed in triple negative breast cancer (TNBC) whilst BMP4, GDF15, ACVR1B, ACVR2B and BMPR1B were relatively higher in Luminal type BC. ACVR1B and BMPR1B were positively correlated with ERα but were inversely correlated with ERβ. High expression of GDF15, BMP4 and ACVR1B were associated with poorer overall survival in HER2 positive BC. BMPs also play dual roles in tumour growth and metastasis of BC.

Conclusion

A shift pattern of BMPs was showed in different subtypes of breast cancer suggesting a subtype specific involvement. It provokes more research to shed light on the exact role of these BMPs and receptors in the disease progression and distant metastasis through a regulation of proliferation, invasion and EMT.

The CDK4/6 Inhibitor Palbociclib Inhibits Estrogen-Positive and Triple Negative Breast Cancer Bone Metastasis In Vivo

CDK 4/6 inhibitors have demonstrated significant improved survival for patients with estrogen receptor (ER) positive breast cancer (BC). However, the ability of these promising agents to inhibit bone metastasis from either ER+ve or triple negative BC (TNBC) remains to be established. We therefore investigated the effects of the CDK 4/6 inhibitor, palbociclib, using in vivo models of breast cancer bone metastasis. In an ER+ve T47D model of spontaneous breast cancer metastasis from the mammary fat pad to bone, primary tumour growth and the number of hind limb skeletal tumours were significantly lower in palbociclib treated animals compared to vehicle controls. In the TNBC MDA-MB-231 model of metastatic outgrowth in bone (intracardiac route), continuous palbociclib treatment significantly inhibited tumour growth in bone compared to vehicle. When a 7-day break was introduced after 28 days (mimicking the clinical schedule), tumour growth resumed and was not inhibited by a second cycle of palbociclib, either alone or when combined with the bone-targeted agent, zoledronic acid (Zol), or a CDK7 inhibitor. Downstream phosphoprotein analysis of the MAPK pathway identified a number of phosphoproteins, such as p38, that may contribute to drug-insensitive tumour growth. These data encourage further investigation of targeting alternative pathways in CDK 4/6-insensitive tumour growth.

Bone morphogenetic protein pathway responses and alterations of osteogenesis in metastatic prostate cancers

BACKGROUND

Prostate cancer is a common cancer in men that annually results in more than 33 000 US deaths. Mortality from prostate cancer is largely from metastatic disease, reflecting on the great strides in the last century of treatments in care for the localized disease. Metastatic castrate resistant prostate cancer (mCRPC) will commonly travel to the bone, creating unique bone pathology that requires nuanced treatments in those sites with surgical, radio and chemotherapeutic interventions. The bone morphogenetic protein (BMP) pathway has been historically studied in the capacity to regulate the osteogenic nature of new bone. New mineralized bone generation is a frequent and common observation in mCRPC and referred to as blastic bone lesions. Less common are bone destructive lesions that are termed lytic.

METHODS

We queried the cancer genome atlas (TCGA) prostate cancer databases for the expression of the BMP pathway and found that distinct gene expression of the ligands, soluble antagonists, receptors, and intracellular mediators were altered in localized versus metastatic disease. Human prostate cancer cell lines have an innate ability to promote blastic- or lytic-like bone lesions and we hypothesized that inhibiting BMP signaling in these cell lines would result in a distinct change in osteogenesis gene expression with BMP inhibition.

RESULTS

We found unique and common changes by comparing these cell lines response and unique BMP pathway alterations. We treated human PCa cell lines with distinct bone pathologic phenotypes with the BMP inhibitor DMH1 and found distinct osteogenesis responses. We analyzed distinct sites of metastatic PCa in the TCGA and found that BMP signaling was selectively altered in commons sites such as lymph node, bone and liver compared to primary tumors.

CONCLUSIONS

Overall we conclude that BMPs in metastatic prostate cancer are important signals and functional mediators of diverse processes that have potential for individualized precision oncology in mCRPC.

Formation and characterization of BMP2/GDF5 and BMP4/GDF5 heterodimers

BACKGROUND

Proteins of the TGFβ family, which are largely studied as homodimers, are also known to form heterodimers with biological activity distinct from their component homodimers. For instance, heterodimers of bone morphogenetic proteins, including BMP2/BMP7, BMP2/BMP6, and BMP9/BMP10, among others, have illustrated the importance of these heterodimeric proteins within the context of TGFβ signaling.

RESULTS

In this study, we have determined that mature GDF5 can be combined with mature BMP2 or BMP4 to form BMP2/GDF5 and BMP4/GDF5 heterodimer. Intriguingly, this combination of a BMP2 or BMP4 monomer, which exhibit high affinity to heparan sulfate characteristic to the BMP class, with a GDF5 monomer with low heparan sulfate affinity produces a heterodimer with an intermediate affinity. Using heparin affinity chromatography to purify the heterodimeric proteins, we then determined that both the BMP2/GDF5 and BMP4/GDF5 heterodimers consistently signaled potently across an array of cellular and in vivo systems, while the activities of their homodimeric counterparts were more context dependent. These differences were likely driven by an increase in the combined affinities for the type 1 receptors, Alk3 and Alk6. Furthermore, the X-ray crystal structure of BMP2/GDF5 heterodimer was determined, highlighting the formation of two asymmetric type 1 receptor binding sites that are both unique relative to the homodimers.

CONCLUSIONS

Ultimately, this method of heterodimer production yielded a signaling molecule with unique properties relative to the homodimeric ligands, including high affinity to multiple type 1 and moderate heparan binding affinity.

A Group of Tumor-Suppressive micro-RNAs Changes Expression Coordinately in Colon Cancer

MicroRNAs (miRNAs) are molecules with a role in the post-transcriptional regulation of messenger RNA, being involved in a wide range of biological and pathological processes. In the present study, we aim to characterize the behavior of a few miRNAs with roles in the cell cycle and differentiation of colon cancer (CC) cells. The present work considers miRNAs as reflections of the complex cellular processes in which they are generated, their observed variations being used to characterize the molecular networks in which they are part and through which cell proliferation is achieved. Tumoral and adjacent normal tissue samples were obtained from 40 CC patients, and the expression of miR-29a, miR-146a, miR-215 and miR-449 were determined by qRT-PCR analysis. Subsequent bioinformatic analysis was performed to highlight the transcription factors (TFs) network that regulate the miRNAs and functionally characterizes this network. There was a significant decrease in the expression of all miRNAs in tumor tissue. All miRNAs were positively correlated with each other. The analysis of the TF network showed tightly connected functional modules related to the cell cycle and associated processes. The four miRNAs are downregulated in CC; they are strongly correlated, showing coherence within the cellular network that regulates them and highlighting possible approach strategies.

The Impact of BMP-4 Tissue Expression on Progression and Survival in Breast Cancer

Background

Bone morphogenetic protein -4 (BMP-4) plays important role in many aspects of carcinogenesis but is also involved in progression and metastasis of breast cancer where its precise role is yet to be elucidated.

Objective

Since the majority of studies related to BMP-4 expression in breast cancer were conducted on cell lines of mouse models, we aimed to investigate BMP-4 tissue expression in primary human breast cancer and to correlate it with standard pathological factors for breast cancer, progression and survival.

Methods

We analyzed immunohistochemical expression of BMP-4 in primary breast cancer tissue of 97 patients, correlated it with standard pathological factors for breast cancer and investigated its impact on progression and survival.

Results

BMP-4 expression was positive in 74.23% breast cancer tissue specimens. We found that hormone positive breast tumors are more likely to show BMP-4 strong granular staining pattern (p<0.01; p=0.029, respectively). There was significant association between stage group and BMP-4 expression in order that stage III breast cancer group were predominantly BMP-4 positive tumors (p=0.046). Although the most common site of distant metastases in patients with BMP-4 positive tumors were bones, we found no significant association (p>0.05). Patients with BMP-4 positive breast cancer showed longer overall and progression-free survival, but the results did not reach statistical significance (p>0.05).

Conclusion

The results of our study in some extent can confirm the current available data and suggest that the role of BMP-4 in breast cancer is ambiguous, acting both as tumor suppressor and tumor promoter in breast cancer. For final elucidation of its impact on survival and progression in breast cancer, multicentric studies on larger sample size are required.

Bone morphogenetic proteins, activins, and growth and differentiation factors in tumor immunology and immunotherapy resistance

The TGF-β superfamily is a group of secreted polypeptides with key roles in exerting and regulating a variety of physiologic effects, especially those related to cell signaling, growth, development, and differentiation. Although its central member, TGF-β, has been extensively reviewed, other members of the family-namely bone morphogenetic proteins (BMPs), activins, and growth and differentiation factors (GDFs)-have not been as thoroughly investigated. Moreover, although the specific roles of TGF-β signaling in cancer immunology and immunotherapy resistance have been extensively reported, little is known of the roles of BMPs, activins, and GDFs in these domains. This review focuses on how these superfamily members influence key immune cells in cancer progression and resistance to treatment.

Biological and Clinical Aspects of Metastatic Spinal Tumors

Simple Summary

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Our literature review aimed to describe the up-to-date knowledge about the molecular pathways and biomarkers engaged in the spine’s metastatic processes. Moreover, we described current data regarding bone-targeted treatment, the emerging targeted therapies, radiotherapy, and immunotherapy used for the treatment of spine metastases. We hope that knowledge comprehensively presented in our review will contribute to the development of novel drugs targeting specific biomarkers and pathways. The more we learn about the molecular aspects of cancer metastasis, the easier it will be to look for treatment methods that will allow us to precisely kill tumor cells.

Abstract

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Thanks to continuous research, there appears more and more detailed knowledge about cancer and metastasis, but these transformations are extremely complicated, e.g., due to the complexity of reactions, the variety of places where they occur, or the participation of both tumor cells and host cells in these transitions. The right target points in tumor metastasis mechanisms are still being researched; that will help us in the proper diagnosis as well as in finding the right treatment. In this literature review, we described the current knowledge about the molecular pathways and biomarkers engaged in metastatic processes involving the spine. We also presented a current bone-targeted treatment for spine metastases and the emerging therapies targeting the discussed molecular mechanisms.

The expression of BMP, integrin, ZEB2 in ovarian high-grade serous carcinoma in relation with lymph node metastasis

Ovarian cancer (OC) is clinically important because it is diagnosed late and has metastasis when it is diagnosed. Mortality risk increases 2.75 times in the presence of lymph node (LN) metastasis. During metastasis, many molecules including BMPs originated from stroma, and tumor cells participate through transcription factors and integrins for cytoskeleton regulation during cell migration. We hypothesized an inverse correlation between BMP2 and BMP7 along with changes in ZEB2, and integrin α5β1 in high-grade OCs in relation to LN metastasis. The BMP2 immunoreactivity was strong along with strong ZEB2 and weak integrins' immunoreactivity in samples with LN metastasis. Strong immunoreactivity of BMP7 was accompanied by strong immunoreactivity of integrins in the samples without LN metastasis. Study results showed BMP2's strong positive immunoreactivity and weak BMP7 immunoreactivity in tumor cells with a significantly weak inverse correlation. This inverse correlation should be considered as both BMPs have different effects in the window of cancer progression and invasion.

Lysosomal protein transmembrane 5 promotes lung-specific metastasis by regulating BMPR1A lysosomal degradation

Organotropism during cancer metastasis occurs frequently but the underlying mechanism remains poorly understood. Here, we show that lysosomal protein transmembrane 5 (LAPTM5) promotes lung-specific metastasis in renal cancer. LAPTM5 sustains self-renewal and cancer stem cell-like traits of renal cancer cells by blocking the function of lung-derived bone morphogenetic proteins (BMPs). Mechanistic investigations showed that LAPTM5 recruits WWP2, which binds to the BMP receptor BMPR1A and mediates its lysosomal sorting, ubiquitination and ultimate degradation. BMPR1A expression was restored by the lysosomal inhibitor chloroquine. LAPTM5 expression could also serve as an independent predictor of lung metastasis in renal cancer. Lastly, elevation of LAPTM5 expression in lung metastases is a common phenomenon in multiple cancer types. Our results reveal a molecular mechanism underlying lung-specific metastasis and identify LAPTM5 as a potential therapeutic target for cancers with lung metastasis.

The mechanisms that confer lung-specific metastasis in renal cell carcinomas (RCC) remain to be detailed. Here the authors show that LAPTM5 contributes to lung-specific metastasis of RCCs by suppressing BMP signalling and thus, enhancing self-renewal and cancer stem cell-like traits of RCCs.

Embryonic Programs in Cancer and Metastasis—Insights From the Mammary Gland

Cancer is characterized as a reversion of a differentiated cell to a primitive cell state that recapitulates, in many aspects, features of embryonic cells. This review explores the current knowledge of developmental mechanisms that are essential for embryonic mouse mammary gland development, with a particular focus on genes and signaling pathway components that are essential for the induction, morphogenesis, and lineage specification of the mammary gland. The roles of these same genes and signaling pathways in mammary gland or breast tumorigenesis and metastasis are then summarized. Strikingly, key embryonic developmental pathways are often reactivated or dysregulated during tumorigenesis and metastasis in processes such as aberrant proliferation, epithelial-to-mesenchymal transition (EMT), and stem cell potency which affects cellular lineage hierarchy. These observations are in line with findings from recent studies using lineage tracing as well as bulk- and single-cell transcriptomics that have uncovered features of embryonic cells in cancer and metastasis through the identification of cell types, cell states and characterisation of their dynamic changes. Given the many overlapping features and similarities of the molecular signatures of normal development and cancer, embryonic molecular signatures could be useful prognostic markers for cancer. In this way, the study of embryonic development will continue to complement the understanding of the mechanisms of cancer and aid in the discovery of novel therapeutic targets and strategies.

The Signaling Pathways Associated With Breast Cancer Bone Metastasis

BACKGROUND

Breast cancer (BC) is now the leading cause of cancer in women, and bone is the primary site of distant BC metastasis. BC bone metastasis seriously affects the quality of life of patients and increases the mortality rate. However, the mechanism of BC bone metastasis is not fully understood.

MAIN BODY

Paget's "seed and soil" hypothesis led experts to explore the relationship between surface markers and receptors in breast tumors and various growth factors in bone. The relevant breast tumor markers serve as "seeds", and the bone microenvironment that is suitable for the survival of the tumor serves as the "soil". These factors interact to make up an entire system and form feedback pathways that accelerate the production of various cytokines, attracting BC cells to migrate to bone tissue, which worsens the development of BC and seriously affects the prognosis of patients. This process is a vicious cycle. At present, there are seven major signaling pathways involved in BC bone metastasis: the OPG/RANK/RANKL signaling pathway, TGF-β signaling pathway, IGF system, PI3K-AKT-mTOR signaling pathway, Wnt signaling pathway and Hippo signaling pathway. In addition, FGF-FGFR signaling pathway, androgen-AR/LSD1-target gene pathway, Notch signaling pathway, JAK-STAT signaling pathway and CaN/NFATC1 signaling pathway also seem to be associated with BC bone metastasis.

CONCLUSION

This review focuses on the signaling pathways related to BC bone metastasis and explores the interactions among these pathways, which will lay a solid theoretical foundation for further understanding the mechanism of BC bone metastasis and developing effective targeted therapeutic drugs.

Advancing Treatment of Bone Metastases through Novel Translational Approaches Targeting the Bone Microenvironment

Bone metastases represent a lethal condition that frequently occurs in solid tumors such as prostate, breast, lung, and renal cell carcinomas, and increase the risk of skeletal-related events (SREs) including pain, pathologic fractures, and spinal cord compression. This unique metastatic niche consists of a multicellular complex that cancer cells co-opt to engender bone remodeling, immune suppression, and stromal-mediated therapeutic resistance. This review comprehensively discusses clinical challenges of bone metastases, novel preclinical models of the bone and bone marrow microenviroment, and crucial signaling pathways active in bone homeostasis and metastatic niche. These studies establish the context to summarize the current state of investigational agents targeting BM, and approaches to improve BM-targeting therapies. Finally, we discuss opportunities to advance research in bone and bone marrow microenvironments by increasing complexity of humanized preclinical models and fostering interdisciplinary collaborations to translational research in this challenging metastatic niche.

BMP4 enhances anoikis resistance and chemoresistance of breast cancer cells through canonical BMP signaling

Bone morphogenetic proteins (BMPs) regulate cell fate during development and mediate cancer progression. In this study, we investigated the role of BMP4 in proliferation, anoikis resistance, metastatic migration, and drug resistance of breast cancer cells. We utilized breast cancer cell lines and clinical samples representing different subtypes to understand the functional effect of BMP4 on breast cancer. The BMP pathway was inhibited with the small molecule inhibitor LDN193189 hydrochloride (LDN). BMP4 signaling enhanced the expression of stem cell genes CD44, ALDH1A3, anti-apoptotic gene BCL2 and promoted anoikis resistance in MDA-MB-231 breast cancer cells. BMP4 enhanced self-renewal and chemoresistance in MDA-MB-231 by upregulating Notch signaling while LDN treatment abrogated anoikis resistance and proliferation of anoikis resistant breast cancer cells in the osteogenic microenvironment. Conversely, BMP4 downregulated proliferation, colony-forming ability, and suppressed anoikis resistance in MCF7 and SkBR3 cells, while LDN treatment promoted tumor spheroid formation and growth. These findings indicate that BMP4 has a context-dependent role in breast cancer. Further, our data with MDA-MB-231 cells representing triple-negative breast cancer suggest that BMP inhibition might impair its metastatic spread and colonization.

BMP2-induction of FN14 promotes protumorigenic signaling in gynecologic cancer cells

We previously reported that bone morphogenetic protein (BMP) signaling promotes tumorigenesis in gynecologic cancer cells. BMP2 enhances proliferation of ovarian and endometrial cancer cells via c-KIT induction, and triggers epithelial-mesenchymal transition (EMT) by SNAIL and/or SLUG induction, leading to increased cell migration. However, the downstream effectors of BMP signaling in gynecological cancer cells have not been clearly elucidated. In this study, we performed RNA-sequencing of Ishikawa endometrial and SKOV3 ovarian cancer cells after BMP2 stimulation, and identified TNFRSF12A, encoding fibroblast growth factor-inducible 14 (FN14) as a common BMP2-induced gene. FN14 knockdown suppressed BMP2-induced cell proliferation and migration, confirmed by MTS and scratch assays, respectively. In addition, FN14 silencing augmented chemosensitivity of SKOV3 cells. As a downstream effector of BMP signaling, FN14 modulated both c-KIT and SNAIL expression, which are important for growth and migration of ovarian and endometrial cancer cells. These results support the notion that the tumor promoting effects of BMP signaling in gynecological cancers are partially attributed to FN14 induction.

Exosomal non-coding RNAs in Hepatobiliary Cancer: A Rising Star

Hepatobiliary cancers are a heterogeneous group of malignancies with a dismal prognosis. Despite intensive research efforts focused on these tumors, methods for early diagnosis and effective targeted therapies are still lacking. Exosomes, released by most cells, exist in all kinds of body fluids and play an important role in cell-to-cell communication. They are small membranous vesicles containing biological molecules, such as noncoding RNAs (ncRNAs), which are not translated into proteins, but they exert effects on the regulation of gene transcription and translation. There is growing evidence for the essential roles of ncRNAs in exosomes in both physiological and pathological conditions of hepatobiliary cancers. They have been identified as sensitive diagnostic biomarkers as well as potential therapeutic targets. The present review discusses recent findings in the crosstalk between hepatobiliary cancers cells and the surrounding cells of the microenvironment and discuss their potential clinical usage.

Role of the BMP6 protein in breast cancer and other types of cancer

The BMP6 protein (Bone Morphogenetic Protein 6) is part of the superfamily of transforming growth factor-beta (TGF-β) ligands, participates in iron homeostasis, inhibits invasion by increasing adhesions and cell-cell type interactions and induces angiogenesis directly on vascular endothelial cells. BMP6 is coded by a tumor suppressor gene whose subexpression is related to the development and cancer progression; during neoplastic processes, methylation is the main mechanism by which gene silencing occurs. This work presents a review on the role of BMP6 protein in breast cancer (BC) and other types of cancer. The studies carried out to date suggest the participation of the BMP6 protein in the epithelial-mesenchymal transition (EMT) phenotype, cell growth and proliferation; however, these processes are affected in a variable way in the different types of cancer, the methylated CpG sites in BMP6 gene promoter, as well as the interaction with other proteins could be the cause of such variation.

Osteolytic metastasis in breast cancer: effective prevention strategies

INTRODUCTION

Breast cancer is the most common cancer in women throughout the world. Patients who are diagnosed early generally have better prognosis and survivability. Indeed, advanced stage breast cancer often develops osteolytic metastases, leading to bone destruction. Although there are select drugs available to treat bone metastatic disease, these drugs have shown limited success.

AREA COVERED

This paper emphasizes updated mechanisms of bone remodeling and osteolytic bone metastases of breast cancer. This article also aims to explore the potential of novel natural and synthetic therapeutics in the effective prevention of breast cancer-induced osteolysis and osteolytic metastases of breast cancer.

EXPERT OPINION

Targeting TGFβ and BMP signaling pathways, along with osteoclast activity, appears to be a promising therapeutic strategy in the prevention of breast cancer-induced osteolytic bone destruction and metastatic growth at bone metastatic niches. Pilot studies in animal models suggest various natural and synthetic compounds and monoclonal antibodies as putative therapeutics in the prevention of breast cancer stimulated osteolytic activity. However, comprehensive pre-clinical studies demonstrating the PK/PD and in-depth understanding of molecular mechanism(s) by which these potential molecules exhibit anti-tumor growth and anti-osteolytic activity are still required to develop effective therapies against breast cancer-induced osteolytic bone disease.

Secreted BMP antagonists and their role in cancer and bone metastases

Bone morphogenetic proteins (BMPs) are multifunctional secreted cytokines that act in a highly context-dependent manner. BMP action extends beyond the induction of cartilage and bone formation, to encompass pivotal roles in controlling tissue and organ homeostasis during development and adulthood. BMPs signal via plasma membrane type I and type II serine/threonine kinase receptors and intracellular SMAD transcriptional effectors. Exquisite temporospatial control of BMP/SMAD signalling and crosstalk with other cellular cues is achieved by a series of positive and negative regulators at each step in the BMP/SMAD pathway. The interaction of BMP ligand with its receptors is carefully controlled by a diverse set of secreted antagonists that bind BMPs and block their interaction with their cognate BMP receptors. Perturbations in this BMP/BMP antagonist balance are implicated in a range of developmental disorders and diseases, including cancer. Here, we provide an overview of the structure and function of secreted BMP antagonists, and summarize recent novel insights into their role in cancer progression and bone metastasis. Gremlin1 (GREM1) is a highly studied BMP antagonist, and we will focus on this molecule in particular and its role in cancer. The therapeutic potential of pharmacological inhibitors for secreted BMP antagonists for cancer and other human diseases will also be discussed.

Sensitivity to differential NRF1 gene signatures contributes to breast cancer disparities

PURPOSE

Nuclear respiratory factor 1 (NRF1) drives estrogen-dependent breast tumorigenesis. Herein we examined the impact of NRF1 activity on the aggressiveness and disparate molecular signature of breast cancer in Black, White, Asian, and Hispanic women.

METHODS

NRF1 activity by transcription factor target enrichment analysis and causal NRF1-target gene signatures by Bayesian Network Inference with Java Objects (BANJO) and Markov Chain Monte Carlo (MCMC)-based gene order were examined in The Cancer Genome Atlas (TCGA) breast cancer cohorts.

RESULTS

We are the first to report increased NRF1 activity based on its differential effects on genome-wide transcription associated with luminal A and B, HER2+ and triple-negative (TN) molecular subtypes of breast cancer in women of different race/ethnicity. We observed disparate NRF1 motif-containing causal gene signatures unique to Black, White, Asian, and Hispanic women for luminal A breast cancer. Further gene order searches showed molecular heterogeneity of each subtype of breast cancer. Six different gene order sequences involving CDK1, HMMR, CCNB2, CCNB1, E2F1, CREB3L4, GTSE1, and LMNB1 with almost equal weight predicted the probability of luminal A breast cancer in whites. Three different gene order sequences consisting of CCNB1 and GTSE1, and CCNB1, LMNB1, CDK1 or CASP3 predicted almost 100% probability of luminal B breast cancer in whites; CCNB1 and LMNB1 or GTSE predicted 100% HER2+ breast cancer in whites. GTSE1 and TUBA1C combined together predicted 100% probability of developing TNBC in whites; NRF1, TUBA1B and BAX with EFNA4, and NRF1 and BTRC predicated 100% TNBC in blacks. High expressor NRF1 TN breast tumors showed unfavorable prognosis with a high risk of breast cancer death in white women.

CONCLUSION

Our findings showed how sensitivity to high NRF1 transcriptional activity coupled with its target gene signatures contribute to racial differences in luminal A and TN breast cancer subtypes. This knowledge may be useful in personalized intervention to prevent and treat this clinically challenging problem.

Genome-wide DNA methylation analysis of KRAS mutant cell lines

Oncogenic RAS mutations are associated with DNA methylation changes that alter gene expression to drive cancer. Recent studies suggest that DNA methylation changes may be stochastic in nature, while other groups propose distinct signaling pathways responsible for aberrant methylation. Better understanding of DNA methylation events associated with oncogenic KRAS expression could enhance therapeutic approaches. Here we analyzed the basal CpG methylation of 11 KRAS-mutant and dependent pancreatic cancer cell lines and observed strikingly similar methylation patterns. KRAS knockdown resulted in unique methylation changes with limited overlap between each cell line. In KRAS-mutant Pa16C pancreatic cancer cells, while KRAS knockdown resulted in over 8,000 differentially methylated (DM) CpGs, treatment with the ERK1/2-selective inhibitor SCH772984 showed less than 40 DM CpGs, suggesting that ERK is not a broadly active driver of KRAS-associated DNA methylation. KRAS G12V overexpression in an isogenic lung model reveals >50,600 DM CpGs compared to non-transformed controls. In lung and pancreatic cells, gene ontology analyses of DM promoters show an enrichment for genes involved in differentiation and development. Taken all together, KRAS-mediated DNA methylation are stochastic and independent of canonical downstream effector signaling. These epigenetically altered genes associated with KRAS expression could represent potential therapeutic targets in KRAS-driven cancer.

Increased Expression of Gremlin1 Promotes Proliferation and Epithelial Mesenchymal Transition in Gastric Cancer Cells and Correlates With Poor Prognosis of Patients With Gastric Cancer

BACKGROUND/AIM

Gremlin1 (GREM1) plays an important role in certain malignancies by antagonising bone morphogenetic proteins and regulating angiogenesis directly/indirectly. The present study aimed to investigate the role of Gremlin1 in the development and progression of gastric cancer (GC).

MATERIALS AND METHODS

Expression of GREM1 in GCs was examined using quantitative real time PCR and The Cancer Genomic Atlas (TCGA) data. Influence on cellular functions was determined in both Gremlin1 knockdown and overexpression cell line models.

RESULTS

GREM1 expression was up-regulated in GCs, which was correlated with poorer survival. Increased GREM1 expression was significantly correlated with tumour growth/invasion and lymphatic metastasis. Gremlin1 promoted proliferation and tumourigenic capacity of GC cells in vitro. GREM1 expression was associated with epithelial mesenchymal transition (EMT), angiogenesis and lymphangiogenesis in GC.

CONCLUSION

Increased GREM1 expression in GCs is associated with disease progression and poor prognosis in which EMT, angiogenesis and lymphangiogenesis are likely involved.

Unresolved Complexity in the Gene Regulatory Network Underlying EMT

Epithelial to mesenchymal transition (EMT) is the process whereby a polarized epithelial cell ceases to maintain cell-cell contacts, loses expression of characteristic epithelial cell markers, and acquires mesenchymal cell markers and properties such as motility, contractile ability, and invasiveness. A complex process that occurs during development and many disease states, EMT involves a plethora of transcription factors (TFs) and signaling pathways. Whilst great advances have been made in both our understanding of the progressive cell-fate changes during EMT and the gene regulatory networks that drive this process, there are still gaps in our knowledge. Epigenetic modifications are dynamic, chromatin modifying enzymes are vast and varied, transcription factors are pleiotropic, and signaling pathways are multifaceted and rarely act alone. Therefore, it is of great importance that we decipher and understand each intricate step of the process and how these players at different levels crosstalk with each other to successfully orchestrate EMT. A delicate balance and fine-tuned cooperation of gene regulatory mechanisms is required for EMT to occur successfully, and until we resolve the unknowns in this network, we cannot hope to develop effective therapies against diseases that involve aberrant EMT such as cancer. In this review, we focus on data that challenge these unknown entities underlying EMT, starting with EMT stimuli followed by intracellular signaling through to epigenetic mechanisms and chromatin remodeling.

Bone morphogenetic proteins mediate crosstalk between cancer cells and the tumour microenvironment at primary tumours and metastases (Review)

Bone morphogenetic proteins (BMP) are pluripotent molecules, co‑ordinating cellular functions from early embryonic and postnatal development to tissue repair, regeneration and homeostasis. They are also involved in tumourigenesis, disease progression and the metastasis of various solid tumours. Emerging evidence has indicated that BMPs are able to promote disease progression and metastasis by orchestrating communication between cancer cells and the surrounding microenvironment. The interactions occur between BMPs and epidermal growth factor receptor, hepatocyte growth factor, fibroblast growth factor, vascular endothelial growth factor and extracellular matrix components. Overall, these interactions co‑ordinate the cellular functions of tumour cells and other types of cell in the tumour to promote the growth of the primary tumour, local invasion, angiogenesis and metastasis, and the establishment and survival of cancer cells in the metastatic niche. Therefore, the present study aimed to provide an informative summary of the involvement of BMPs in the tumour microenvironment.

A Multi-Omics Analysis of Bone Morphogenetic Protein 5 (BMP5) mRNA Expression and Clinical Prognostic Outcomes in Different Cancers Using Bioinformatics Approaches

Cumulative studies have provided controversial evidence for the prognostic values of bone morphogenetic protein 5 (BMP5) in different types of cancers such as colon, breast, lung, bladder, and ovarian cancer. To address the inconsistent correlation of BMP5 expression with patient survival and molecular function of BMP5 in relation to cancer progression, we performed a systematic study to determine whether BMP5 could be used as a prognostic marker in human cancers. BMP5 expression and prognostic values were assessed using different bioinformatics tools such as ONCOMINE, GENT, TCGA, GEPIA, UALCAN, PrognoScan, PROGgene V2 server, and Kaplan-Meier Plotter. In addition, we used cBioPortal database for the identification and analysis of BMP5 mutations, copy number alterations, altered expression, and protein-protein interaction (PPI). We found that BMP5 is frequently down-regulated in our queried cancer types. Use of prognostic analysis showed negative association of BMP5 down-regulation with four types of cancer except for ovarian cancer. The highest mutation was found in the R321*/Q amino acid of BMP5 corresponding to colorectal and breast cancer whereas the alteration frequency was higher in lung squamous carcinoma datasets (>4%). In PPI analysis, we found 31 protein partners of BMP5, among which 11 showed significant co-expression (p-value < 0.001, log odds ratio > 1). Pathway analysis of differentially co-expressed genes with BMP5 in breast, lung, colon, bladder and ovarian cancers revealed the BMP5-correlated pathways. Collectively, this data-driven study demonstrates the correlation of BMP5 expression with patient survival and identifies the involvement of BMP5 pathways that may serve as targets of a novel biomarker for various types of cancers in human.

BMP-4 enhances epithelial mesenchymal transition and cancer stem cell properties of breast cancer cells via Notch signaling

Bone morphogenetic protein (BMP) signaling and Notch signaling play important roles in tumorigenesis in various organs and tissues, including the breast. BMP-4 enhanced epithelial mesenchymal transition (EMT) and stem cell properties in both mammary epithelial cell line and breast carcinoma cell line. BMP-4 increased the expression of EMT biomarkers, such as fibronectin, laminin, N-cadherin, and Slug. BMP-4 also activated Notch signaling in these cells and increased the sphere forming efficiency of the non-transformed mammary epithelial cell line MCF-10A. In addition, BMP-4 upregulated the sphere forming efficiency, colony formation efficiency, and the expression of cancer stem cell markers, such as Nanog and CD44, in the breast carcinoma cell line MDA-MB-231. Inhibition of Notch signaling downregulated EMT and stem cell properties induced by BMP-4. Down-regulation of Smad4 using siRNA impaired the BMP-4-induced activation of Notch signaling, as well as the BMP-4-mediated EMT. These results suggest that EMT and stem cell properties are increased in mammary epithelial cells and breast cancer cells through the activation of Notch signaling in a Smad4-dependent manner in response to BMP-4.

Multi-network approach to identify differentially methylated gene communities in cancer

BACKGROUND AND OBJECTIVE

High-throughput Next Generation Sequencing tools have generated immense quantity of genome-wide methylation and expression profiling data, resulting in an unprecedented opportunity to unravel the epigenetic regulatory mechanisms underlying cancer. Identifying differentially methylated regions within gene networks is an important step towards revealing the cancer epigenome blueprint. Approaches that integrate gene methylation and expression profiles assume their negative correlation and build a single scaffold network to cluster. However, the exact regulatory mechanism between gene expression and methylation is not precisely deciphered.

METHODS

A consensus-based clustering framework, namely, Differentially Methylated Gene Communities based on Multi-network (DMGC-M) is proposed, that takes multiple gene networks as input and builds a community structure out of evidences from all network types.

RESULTS

Experiments on six cancer datasets from The Cancer Genome Atlas (TCGA) reveal that multi-network approaches produce more discriminative gene communities than integrated approaches.

CONCLUSION

The proposed method will be useful to a number of researchers who seek to identify epigenetic dysregulations in pathways or molecular networks. The findings can also advance recent research efforts in Molecular Pathologic Epidemiology.

A humanized bone microenvironment uncovers HIF2 alpha as a latent marker for osteosarcoma

The quest for predictive tumor markers for osteosarcoma (OS) has not well progressed over the last two decades due to a lack of preclinical models. The aim of this study was to investigate if microenvironmental modifications in an original humanized in vivo model alter the expression of OS tumor markers. Human bone micro-chips and bone marrow, harvested during hip arthroplasty, were implanted at the flanks of NOD/scid mice. We administered recombinant human bone morphogenetic protein 7 (rhBMP-7) in human bone micro-chips/bone marrow group I in order to modulate bone matrix and bone marrow humanization. Ten weeks post-implantation, human Luc-SAOS-2 OS cells were injected into the humanized tissue-engineered bone organs (hTEBOs). Tumors were harvested 5 weeks post-implantation to determine the expression of the previously described OS markers ezrin, periostin, VEGF, HIF1α and HIF2α. Representation of these proteins was analyzed in two different OS patient cohorts. Ezrin was downregulated in OS in hTEBOs with rhBMP-7, whereas HIF2α was significantly upregulated in comparison to hTEBOs without rhBMP-7. The expression of periostin, VEGF and HIF1α did not differ significantly between both groups. HIF2α was consistently present in OS patients and dependent on tumor site and clinical stage. OS patients post-chemotherapy had suppressed levels of HIF2α. In conclusion, we demonstrated the overall expression of OS-related factors in a preclinical model, which is based on a humanized bone organ. Our preclinical research results and analysis of two comprehensive patient cohorts imply that HIF2α is a potential prognostic marker and/or therapeutic target. STATEMENT OF SIGNIFICANCE: This study demonstrates the clinical relevance of the humanized organ bone microenvironment in osteosarcoma research and validates the expression of tumor markers, especially HIF2α. The convergence of clinically proven bone engineering concepts for the development of humanized mice models is a new starting point for investigations of OS-related marker expression. The validation and first data set in such a model let one conclude that further clinical studies on the role of HIF2α as a prognostic marker and its potential as therapeutic target is a condition sine qua non.

Bone morphogenetic protein signaling in breast cancer progression

Breast cancer is the most prevalent type of cancer amongst women worldwide. The mortality rate for patients with early-stage breast cancer has been decreasing, however, the 5-year survival rate for patients with metastatic disease remains poor, currently at 27%. Here, we have reviewed the current understanding of the role of bone morphogenetic protein (BMP) signaling in breast cancer progression, and have highlighted the discordant results that are reported in different studies. We propose that some of these contradictory outcomes may result from signaling through either the canonical or non-canonical pathways in different cell lines and tumors, or from different tumor-stromal interactions that occur in vivo.

Investigation into the Molecular Mechanisms underlying the Anti-proliferative and Anti-tumorigenesis activities of Diosmetin against HCT-116 Human Colorectal Cancer

Diosmetin (Dis) is a bioflavonoid with cytotoxicity properties against variety of cancer cells including hepatocarcinoma, breast and colorectal (CRC) cancer. The exact mechanism by which Dis acts against CRC however, still remains unclear, hence in this study, we investigated the possible molecular mechanisms of Dis in CRC cell line, HCT-116. Here, we monitored the viability of HCT-116 cells in the presence of Dis and investigated the underlying mechanism of Dis against HCT-116 cells at the gene and protein levels using NanoString and proteome profiler array technologies. Findings demonstrated that Dis exhibits greater cytotoxic effects towards HCT-116 CRC cells (IC50 = 3.58 ± 0.58 µg/ml) as compared to the normal colon CCD-841 cells (IC50 = 51.95 ± 0.11 µg/ml). Arrests of the cells in G2/M phase confirms the occurrence of mitotic disruption via Dis. Activation of apoptosis factors such as Fas and Bax at the gene and protein levels along with the release of Cytochrome C from mitochondria and cleavage of Caspase cascades indicate the presence of turbulence as a result of apoptosis induction in Dis-treated cells. Moreover, NF-ƙB translocation was inhibited in Dis-treated cells. Our results indicate that Dis can target HCT-116 cells through the mitotic disruption and apoptosis induction.

miR-125a/b inhibits tumor-associated macrophages mediated in cancer stem cells of hepatocellular carcinoma by targeting CD90

Cancer stem cells promote tumorigenesis and progression of hepatocellular carcinoma (HCC). Recently, emerging evidence indicates tumor-associated macrophages (TAMs) play an important role in tumor progression. However, TAMs often occurs with unknown mechanisms. As an important mediator in intercellular communications, exosomes secreted by host cells mediate the exchange of genetic materials and proteins, which involves tumor aggressiveness. The aim of the study was to investigate whether exosomes derived from TAMs mediate stem cell properties in HCC. TAMs were isolated from the tissues of HCC. microRNA (miRNA) expression profiles of TAMs were analyzed using miRNA microarray. In vitro cell coculture was further conducted to investigate the crosstalk between TAMs and tumor cells mediated by TAMs exosomes. In this study, we showed that TAMs exosomes promote HCC cell proliferation and stem cell properties. Using miRNA profiles assay, we identified significantly lower levels of miR-125a and miR-125b in exosomes and cell lysate isolated from TAMs. Functional studies revealed that the HCC cells were treated with TAM exosomes or transfected with miR-125a/b suppressed cell proliferation and stem cell properties by targeting CD90, a stem cell marker of HCC stem cells. The study indicated that miR-125a/b targeting CD90 played important roles in cancer stem cells of HCC.

HOXA11 antisense long noncoding RNA (HOXA11-AS): A promising lncRNA in human cancers

The cancers are the leading cause of disease‐related deaths worldwide with a high risk of morbidity and mortality. Long noncoding RNAs (lncRNAs) play a critical role in a wide range of biological processes, including tumorigenesis. HOXA11‐AS (NCRNA00076), the antisense strands of HOXA11 gene, was initially revealed in a mouse embryonic cDNA library in 2009 and it was a fairly novel lncRNA. This review summarized the advanced research progression concerning the expression and role of HOXA11‐AS in different human malignancies. The expression of HOXA11‐AS is aberrantly altered in many cancers, either as a tumor suppressor or as a tumor accelerator. The different underlying mechanism of HOXA11‐AS in different cancers (including, nonsmall cell lung cancers, osteosarcoma, uveal melanoma, glioma, hepatocellular carcinoma, gastric cancer, breast cancer, cervical cancer, ovarian cancer, colorectal cancer, ovarian cancer, and glioblastoma) was also detailed. These findings lead us to conclude that HOXA11‐AS participate in the complex network of cancers and plays an important role in the tumorigenesis and progression. Functional HOXA11‐AS could be a promising biomarker for early detection as well as prognosis evaluation in cancer patients. Future HOXA11‐AS‐targeted intervention may become a valuable novel therapeutic tool, improving the clinical management of cancers.

Deregulation of Negative Controls on TGF-β1 Signaling in Tumor Progression

The multi-functional cytokine transforming growth factor-β1 (TGF-β1) has growth inhibitory and anti-inflammatory roles during homeostasis and the early stages of cancer. Aberrant TGF-β activation in the late-stages of tumorigenesis, however, promotes development of aggressive growth characteristics and metastatic spread. Given the critical importance of this growth factor in fibrotic and neoplastic disorders, the TGF-β1 network is subject to extensive, multi-level negative controls that impact receptor function, mothers against decapentaplegic homolog 2/3 (SMAD2/3) activation, intracellular signal bifurcation into canonical and non-canonical pathways and target gene promotor engagement. Such negative regulators include phosphatase and tensin homologue (PTEN), protein phosphatase magnesium 1A (PPM1A), Klotho, bone morphogenic protein 7 (BMP7), SMAD7, Sloan-Kettering Institute proto-oncogene/ Ski related novel gene (Ski/SnoN), and bone morphogenetic protein and activin membrane-bound Inhibitor (BAMBI). The progression of certain cancers is accompanied by loss of expression, overexpression, mislocalization, mutation or deletion of several endogenous repressors of the TGF-β1 cascade, further modulating signal duration/intensity and phenotypic reprogramming. This review addresses how their aberrant regulation contributes to cellular plasticity, tumor progression/metastasis and reversal of cell cycle arrest and discusses the unexplored therapeutic value of restoring the expression and/or function of these factors as a novel approach to cancer treatment.

Microcalcifications in breast cancer: From pathophysiology to diagnosis and prognosis

The implementation of mammographic screening programmes in many countries has been linked to a marked increase in early detection and improved prognosis for breast cancer patients. Breast tumours can be detected by assessing several features in mammographic images but one of the most common are the presence of small deposits of calcium known as microcalcifications, which in many cases may be the only detectable sign of a breast tumour. In addition to their efficacy in the detection of breast cancer, the presence of microcalcifications within a breast tumour may also convey useful prognostic information. Breast tumours with associated calcifications display an increased rate of HER2 overexpression as well as decreased survival, increased risk of recurrence, high tumour grade and increased likelihood of spread to the lymph nodes. Clearly, the presence of microcalcifications in a tumour is a clinically significant finding, suggesting that a detailed understanding of their formation may improve our knowledge of the early stages of breast tumourigenesis, yet there are no reports which attempt to bring together recent basic science research findings and current knowledge of the clinical significance of microcalcifications. This review will summarise the most current understanding of the formation of calcifications within breast tissue and explore their associated clinical features and prognostic value.

Serum irisin associates with breast cancer to spinal metastasis

The aim of this study was to determine whether the serum level of irisin can be a candidate to predict the spinal metastasis in patients with breast cancer.In a cross-sectional study, 148 patients were recruited. Of those, 53 (35.8%) had spinal metastasis. The baseline characteristics were compared by status of spinal metastasis. Multiple logistic regression analysis was used to determine whether the serum irisin can be a candidate for predicting breast cancer to spinal metastasis. The correlation coefficient analysis was used to confirm the correlation between the serum irisin and lipid metabolic parameters and body mass index (BMI), respectively.The serum irisin was higher in patients without spinal metastasis (7.60 ± 3.80). Multivariable analysis showed that the serum irisin was protective to the presence of spinal metastasis in patients with breast cancer after adjustments of age and BMI (odds ratio, 0.873; 95% confidence interval, 0.764-0.999). Furthermore, there was a positive correlation between the serum irisin and BMI (r = 0.263). The patients with metabolisc syndrome (MetS) had a higher level in serum irisin. In addition, the higher numbers of MetS components were associated with higher serum irisin.Higher serum irisin can be a protective factor of spinal metastasis in patients with breast cancer. The BMI is positively associated with the serum level of irisin. Furthermore, patients with MetS tended to have a higher level of serum irisin.