Diverse biological effect and Smad signaling of bone morphogenetic protein 7 in prostate tumor cells

Effects of CCN6 overexpression on the cell motility and activation of p38/bone morphogenetic protein signaling pathways in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancer types that is highly resistant to conventional treatments, such as chemotherapy and radiotherapy. As the demand for more effective therapeutics for PDAC treatment increases, various approaches have been studied to develop novel targets. The cellular communication network (CCN) family is a matricellular protein that modulates various cellular functions, including cell adhesion, proliferation, migration, and invasiveness. Despite this, little is known about the role of CCN6 in PDAC. The current study investigated the role of CCN6 in PDAC by generating CCN6-overexpressing PANC-1 cells (PANC-1-CCN6) by infecting lentivirus particles containing CCN6. PANC-1-CCN6 induces cell viability and tumorigenesis than PANC-1 cells with empty vector (control). The PANC-1-CCN6 formed more colonies, and the size of spheroids increased compared to the control. The upregulation of CCN6 enhances the expression of bone morphogenetic proteins (BMPs) genes and the upregulation of p38 mitogen-activated protein kinases (MAPKs). In PANC-1-CCN6 cells, the levels of N-cadherin, VEGF, and Snail expression were higher than the control, while E-cadherin expression was lower, which is associated with upregulation of epithelial-to-mesenchymal transition (EMT). Consistent with the changes in EMT-related proteins in PANC-1-CCN6, the migratory ability and invasiveness were enhanced in PANC-1-CCN6. Xenografted PANC-1-CCN6 in immunocompromised mice exhibited accelerated tumor growth than the control group. In immunohistochemistry (IHC), the PANC-1-CCN6 xenografted tumor showed an increased positive area of PCNA and Ki-67 than the control. These results suggest that CCN6 plays a tumorigenic role and induces the metastatic potential by the p38 MAPK and BMPs signaling pathways. Although the role of CCN6 has been introduced as an antitumor factor, there was evidence of CCN6 acting to cause tumorigenesis and invasion in PANC-1.

BMP2 as a promising anticancer approach: functions and molecular mechanisms

Bone morphogenetic protein 2 (BMP2), a pluripotent factor, is a member of the transforming growth factor-beta (TGF-β) superfamily and is implicated in embryonic development and postnatal homeostasis in tissues and organs. Experimental research in the contexts of physiology and pathology has indicated that BMP2 can induce macrophages to differentiate into osteoclasts and accelerate the osteolytic mechanism, aggravating cancer cell bone metastasis. Emerging studies have stressed the potent regulatory effect of BMP2 in cancer cell differentiation, proliferation, survival, and apoptosis. Complicated signaling networks involving multiple regulatory proteins imply the significant biological functions of BMP2 in cancer. In this review, we comprehensively summarized and discussed the current evidence related to the modulation of BMP2 in tumorigenesis and development, including evidence related to the roles and molecular mechanisms of BMP2 in regulating cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), cancer angiogenesis and the tumor microenvironment (TME). All these findings suggest that BMP2 may be an effective therapeutic target for cancer and a new marker for assessing treatment efficacy.

The role of miR-370 and miR-138 in the regulation of BMP2 suppressor gene expression in colorectal cancer: preliminary studies

PURPOSE

Colorectal cancer (CRC) is the fourth-most common cancer worldwide and the second most common cancer cause of death in the world. The components of the TGFβ-signalling pathway, which are often affected by miRNAs, are involved in the regulation of apoptosis and cell cycle. Therefore, in the current study, the expression of BMP2 gene in CRC tissues at different clinical stages compared to the non-tumour tissues has been assessed. Moreover, the plasma BMP2 protein concentration in the same group of CRC patients has been validated. Due to the constant necessity to conduct further research of the correlation between specific miRNAs and mRNAs in CRC, in silico analysis has been performed to select miRNAs that regulate BMP2 mRNA.

METHODS

The cDNA samples from tumor and non-tumor tissue were used in a qPCR reaction to determine the mRNA expression of the BMP2 gene and the expression of selected miRNAs. The concentration of BMP2 protein in plasma samples was also measured.

RESULTS

It was indicated that BMP2 was downregulated in CRC tissue. Moreover, miR-370 and miR-138 expression showed an upward trend. Decreased BMP2 with accompanied increasing miR-370 and miR-138 expression was relevant to the malignant clinicopathological features of CRC and consequently poor patient prognosis.

CONCLUSION

Our data suggest that miR-370 with its clear expression in plasma samples may be a potential diagnostic marker to determine the severity of the disease in patients at a later stage of colorectal cancer.

The Prognostic Value of Bone Morphogenetic Proteins and Their Receptors in Lung Adenocarcinoma

Background

Bone morphogenetic proteins (BMPs) regulate tumor progression via binding to their receptors (BMPRs). However, the expression and clinical significance of BMPs/BMPRs in lung adenocarcinoma remain unclear due to a lack of systematic studies.

Methods

This study screened differentially expressed BMPs/BMPRs (deBMPs/BMPRs) in a training dataset combining TCGA-LUAD and GTEx-LUNG and verified them in four GEO datasets. Their prognostic value was evaluated via univariate and multivariate Cox regression analyses. LASSO was performed to construct an initial risk model. Subsequently, after weighted gene co-expression network analysis (WGCNA), differential expression analysis, and univariate Cox regression analysis, hub genes co-expressed with differentially expressed BMPs/BMPRs were filtered out to improve the risk model and explore potential mechanisms. The improved risk model was re-established via LASSO combining hub genes with differentially expressed BMPs/BMPRs as the core. In the testing cohort including 93 lung adenocarcinoma patients, immunohistochemistry (IHC) was performed to verify BMP5 protein expression and its association with prognosis.

Results

BMP2, BMP5, BMP6, GDF10, and ACVRL1 were verified as downregulated in lung adenocarcinoma. Survival analysis identified BMP5 as an independent protective prognostic factor. We also found that BMP5 was significantly correlated with EGFR expression and mutations, suggesting that BMP5 may play a role in targeted therapy. The initial risk model containing only BMP5 showed a significant correlation (HR: 1.71, 95% CI: 1.28−2.28, p: 3e-04) but low prognostic accuracy (AUC of 1-year survival: 0.6, 3-year survival: 0.6, 5-year survival: 0.63). Seventy-nine hub genes co-expressed with BMP5 were identified, and their functions were enriched in cell migration and tumor metastasis. The re-established risk model showed greater prognostic correlation (HR: 2.58, 95% CI: 1.92–3.46, p: 0) and value (AUC of 1-year survival: 0.72, 3-year survival: 0.69, and 5-year survival: 0.68). IHC results revealed that BMP5 protein was also downregulated in lung adenocarcinoma and higher expression was markedly associated with better prognosis (HR: 0.44, 95% CI: 0.23–0.85, p: 0.0145).

Conclusion

BMP5 is a potential crucial target for lung adenocarcinoma treatment based on significant differential expression and superior prognostic value.

Mechanisms, Diagnosis and Treatment of Bone Metastases

Bone and bone marrow are among the most frequent metastatic sites of cancer. The occurrence of bone metastasis is frequently associated with a dismal disease outcome. The prevention and therapy of bone metastases is a priority in the treatment of cancer patients. However, current therapeutic options for patients with bone metastatic disease are limited in efficacy and associated with increased morbidity. Therefore, most current therapies are mainly palliative in nature. A better understanding of the underlying molecular pathways of the bone metastatic process is warranted to develop novel, well-tolerated and more successful treatments for a significant improvement of patients' quality of life and disease outcome. In this review, we provide comparative mechanistic insights into the bone metastatic process of various solid tumors, including pediatric cancers. We also highlight current and innovative approaches to biologically targeted therapy and immunotherapy. In particular, we discuss the role of the bone marrow microenvironment in the attraction, homing, dormancy and outgrowth of metastatic tumor cells and the ensuing therapeutic implications. Multiple signaling pathways have been described to contribute to metastatic spread to the bone of specific cancer entities, with most knowledge derived from the study of breast and prostate cancer. However, it is likely that similar mechanisms are involved in different types of cancer, including multiple myeloma, primary bone sarcomas and neuroblastoma. The metastatic rate-limiting interaction of tumor cells with the various cellular and noncellular components of the bone-marrow niche provides attractive therapeutic targets, which are already partially exploited by novel promising immunotherapies.

Association between chronic periodontitis and the risk of Alzheimer's disease: combination of text mining and GEO dataset

BACKGROUND

Although chronic periodontitis has previously been reported to be linked with Alzheimer's disease (AD), the pathogenesis between the two is unclear. The purpose of this study is to analyze and screen the relevant and promising molecular markers between chronic periodontitis and Alzheimer's disease (AD).

METHODS

In this paper, we analyzed three AD expression datasets and extracted differentially expressed genes (DEGs), then intersected them with chronic periodontitis genes obtained from text mining, and finally obtained integrated DEGs. We followed that by enriching the matching the matching cell signal cascade through DAVID analysis. Moreover, the MCODE of Cytoscape software was employed to uncover the protein-protein interaction (PPI) network and the matching hub gene. Finally, we verified our data using a different independent AD cohort.

RESULTS

The chronic periodontitis gene set acquired from text abstracting was intersected with the previously obtained three AD groups, and 12 common genes were obtained. Functional enrichment assessment uncovered 12 cross-genes, which were mainly linked to cell morphogenesis involved in neuron differentiation, leading edge membrane, and receptor ligand activity. After PPI network creation, the ten hub genes linked to AD were retrieved, consisting of SPP1, THY1, CD44, ITGB1, HSPB3, CREB1, SST, UCHL1, CCL5 and BMP7. Finally, the function terms in the new independent dataset were used to verify the previous dataset, and we found 22 GO terms and one pathway, "ECM-receptor interaction pathways", in the overlapping functional terms.

CONCLUSIONS

The establishment of the above-mentioned candidate key genes, as well as the enriched signaling cascades, provides promising molecular markers for chronic periodontitis-related AD, which may help the diagnosis and treatment of AD patients in the future.

Intracellular Signaling Responses Induced by Radiation within an In Vitro Bone Metastasis Model after Pre-Treatment with an Estrone Analogue

2-Ethyl-3-O-sulfamoyl-estra-1,3,5(10)16-tetraene (ESE-16) is an in silico-designed estradiol analogue which has improved the parent compound’s efficacy in anti-cancer studies. In this proof-of-concept study, the potential radiosensitizing effects of ESE-16 were investigated in an in vitro deconstructed bone metastasis model. Prostate (DU 145) and breast (MDA-MB-231) tumor cells, osteoblastic (MC3T3-E1) and osteoclastic (RAW 264.7) bone cells and human umbilical vein endothelial cells (HUVECs) were representative components of such a lesion. Cells were exposed to a low-dose ESE-16 for 24 hours prior to radiation at non-lethal doses to determine early signaling and molecular responses of this combination treatment. Tartrate-resistant acid phosphatase activity and actin ring formation were investigated in osteoclasts, while cell cycle progression, reactive oxygen species generation and angiogenic protein expression were investigated in HUVECs. Increased cytotoxicity was evident in tumor and endothelial cells while bone cells appeared to be spared. Increased mitotic indices were calculated, and evidence of increased deoxyribonucleic acid damage with retarded repair, together with reduced metastatic signaling was observed in tumor cells. RAW 264.7 macrophages retained their ability to differentiate into osteoclasts. Anti-angiogenic effects were observed in HUVECs, and expression of hypoxia-inducible factor 1-α was decreased. Through preferentially inducing tumor cell death and potentially inhibiting neovascularization whilst preserving bone physiology, this low-dose combination regimen warrants further investigation for its promising therapeutic application in bone metastases management, with the additional potential of limited treatment side effects.

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.

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.

High Levels of BMP2 Promote Liver Cancer Growth via the Activation of Myeloid-Derived Suppressor Cells

Bone morphogenetic protein 2 (BMP2) signaling had significant roles in diverse pathological processes, such as cancer. Nevertheless, the interaction between BMP2 and carcinoma development remained largely unknown. In particular, the roles that BMP2 play in the development of liver cancer remained controversial, and mechanisms were unclear. BMP2 with strong osteogenic potential had been manufactured into various bone materials. However, cancer risk concerns were raised in recent years. Thus, we focused on analyzing the effects of exogenous BMP2 on the growth of liver cancer and the detailed mechanisms. We found that both intravenous injection of rhBMP2 and in vivo implantation of rhBMP2 materials could lead to the expansion of myeloid-derived suppressor cells (MDSCs) in peripheral blood and subsequently enhanced the infiltration of MDSCs into tumor in vivo. Furthermore, BMP2 signaling-activated MDSCs could secrete IL6 to enhance cell proliferation of liver cancer cells in vitro and facilitate liver cancer growth in vivo. Our study indicated that increased concentration of BMP2 within the peripheral blood could enhance liver cancer growth via the activation of MDSCs. In this study, the roles that BMP2 played in liver cancer growth were further confirmed and the detailed mechanisms about how BMP2 enhanced liver cancer growth were also elucidated.

Deregulated bone morphogenetic proteins and their receptors are associated with disease progression of gastric cancer

Bone morphogenetic proteins (BMP) are members of the transforming growth factor β superfamily (TGF-β). BMPs are involved in tumourigenesis and disease progression of certain malignancies. To date, the role played by BMPs in gastric cancer (GC) remains largely unknown. In the present study, we systematically analysed the expression and clinical significance of BMP and BMP receptors (BMPR) in TCGA gastric cancer database and GEO database and explored the possible mechanism of action. BMP5 is reduced in gastric cancer tissues, while ACVRL1, ACVR1, TGFBR1, and BMPR2 were significantly increased in the gastric tumours. BMP3, ACVR1, TGFBR1, BMPR1B (also known as ALK6), TGFBR2 and BMPR2 were significantly associated with poorer overall survival of GC patients. A negative correlation was seen between BMP/BMPR and proliferation markers which was supported by their correlation with the cell cycle promoters and inhibitors. More interestingly, further analyses showed that BMPs and their receptors are positively correlated with matrix metalloproteinases (MMPs), epithelial mesenchymal transition (EMT) markers and stemness in GC. Furthermore, positive correlations were also frequently seen between BMP receptors and markers/regulators of angiogenesis and lymphangiogenesis in the gastric tumours. Taken together, these findings suggest that BMPs play dual roles in GC. They may inhibit proliferation of GC cells. On the other hand, they can also promote disease progression through a promotion of invasion, EMT and stemness. The elevated expression of BMP receptors in GC were also highly associated with tumour associated angiogenesis and lymphangiogenesis which facilitate tumour growth, expansion and spread.

GTF2IRD1 on chromosome 7 is a novel oncogene regulating the tumor-suppressor gene TGFβR2 in colorectal cancer

Chromosome 7q (Ch.7q) is clonally amplified in colorectal cancer (CRC). We aimed to identify oncogenes on Ch.7q that are overexpressed through DNA copy number amplification and determine the biological and clinical significance of these oncogenes in CRC. We identified general transcription factor 2I repeat domain‐containing protein 1 (GTF2IRD1) as a potential oncogene using a CRC dataset from The Cancer Genome Atlas with a bioinformatics approach. We measured the expression of GTF2IRD1 in 98 patients with CRC using immunohistochemistry and RT‐quantitative PCR (RT‐qPCR). The biological effects of GTF2IRD1 expression were explored by gene set enrichment analysis (GSEA). Next, we undertook in vitro cell proliferation and cell cycle assays using siGTF2IRD1‐transfected CRC cells. We further investigated the oncogenic mechanisms through which GTF2IRD1 promoted CRC progression. Finally, we assessed the clinical significance of GTF2IRD1 expression by RT‐qPCR. GTF2IRD1 was overexpressed in tumor cells and liver metastatic lesions. The GSEA revealed a positive correlation between GTF2IRD1 expression and cell cycle progression‐related genes. GTF2IRD1 knockdown inhibited cell proliferation and induced cell cycle arrest in Smad4‐mutated CRC. GTF2IRD1 downregulated the expression of the gene encoding transforming growth factor β receptor 2 (TGFβR2), a tumor‐suppressor gene in Smad4‐mutated CRC. On multivariate analysis, high GTF2IRD1 expression was an independent poor prognostic factor. Clinicopathological analysis showed that GTF2IRD1 expression was positively correlated with liver metastasis. In conclusion, GTF2IRD1 promoted CRC progression by downregulating TGFβR2 and could be a prognostic biomarker on Ch.7q in CRC. GTF2IRD1 could also be a novel oncogene in CRC.

ACVR1 Function in Health and Disease

Activin A receptor type I (ACVR1) encodes for a bone morphogenetic protein type I receptor of the TGFβ receptor superfamily. It is involved in a wide variety of biological processes, including bone, heart, cartilage, nervous, and reproductive system development and regulation. Moreover, ACVR1 has been extensively studied for its causal role in fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder characterised by progressive heterotopic ossification. ACVR1 is linked to different pathologies, including cardiac malformations and alterations in the reproductive system. More recently, ACVR1 has been experimentally validated as a cancer driver gene in diffuse intrinsic pontine glioma (DIPG), a malignant childhood brainstem glioma, and its function is being studied in other cancer types. Here, we review ACVR1 receptor function and signalling in physiological and pathological processes and its regulation according to cell type and mutational status. Learning from different functions and alterations linked to ACVR1 is a key step in the development of interdisciplinary research towards the identification of novel treatments for these pathologies.

CDK8-Novel Therapeutic Opportunities

Improvements in cancer therapy frequently stem from the development of new small-molecule inhibitors, paralleled by the identification of biomarkers that can predict the treatment response. Recent evidence supports the idea that cyclin-dependent kinase 8 (CDK8) may represent a potential drug target for breast and prostate cancer, although no CDK8 inhibitors have entered the clinics. As the available inhibitors have been recently reviewed, we focus on the biological functions of CDK8 and provide an overview of the complexity of CDK8-dependent signaling throughout evolution and CDK8-dependent effects that may open novel treatment avenues.

Expression of Bone Morphogenetic Protein-7 Significantly Correlates With Non-small Cell Lung Cancer Progression and Prognosis: A Retrospective Cohort Study

Background

Bone morphogenetic protein-7 (BMP-7) is a signaling molecule belonging to the transforming growth factor-β superfamily. Recent studies have demonstrated that BMP-7 is expressed in various human cancers and plays an important role in the progression of their cancers. The purpose of this study was to investigate the clinicopathologic and prognostic impact of BMP-7 expression in clinical samples of non-small cell lung cancer.

Methods

This study enrolled 160 patients with non-small cell lung cancer who underwent complete resection. Expression of BMP-7 in cancer tissue was evaluated by immunohistochemistry. Correlations between expression of BMP-7 and clinicopathologic factors and prognosis were analyzed.

Results

In non-small cell lung cancer, BMP-7 expression was identified not only in cell membranes but also in the cytoplasm of cancer cells. Expression of BMP-7 correlated with p-T (P = .047), N factor (P = .013), and p-stage (P = .046). Overall survival rate was significantly lower in the BMP-7-positive group than in the BMP-7-negative group (P = .004). Multivariate analysis indicated that BMP-7 expression was one of the independent prognosis factors of overall survival (P = .021). Furthermore, among patients with postoperative recurrence (n = 58), the BMP-7-positive group (n = 29) had a significantly poorer prognosis than the BMP-7-negative group (n = 29) (P = .012).

Conclusions

Expression of BMP-7 in non-small cell lung cancer was correlated with clinicopathologic factors and poorer prognosis. BMP-7 expression may be a useful predictor of aggressive activity of tumor behavior and postoperative outcome of patients with non-small cell lung cancer.

Opposing roles and potential antagonistic mechanism between TGF-β and BMP pathways: Implications for cancer progression

The transforming growth factor β (TGF-β) superfamily participates in tumour proliferation, apoptosis, differentiation, migration, invasion, immune evasion and extracellular matrix remodelling. Genetic deficiency in distinct components of TGF-β and BMP-induced signalling pathways or their excessive activation has been reported to regulate the development and progression of some cancers. As more in-depth studies about this superfamily have been conducted, more evidence suggests that the TGF-β and BMP pathways play an opposing role. The cross-talk of these 2 pathways has been widely studied in kidney disease and bone formation, and the opposing effects have also been observed in some cancers. However, the antagonistic mechanisms are still insufficiently investigated in cancer. In this review, we aim to display more evidences and possible mechanisms accounting for the antagonism between these 2 pathways, which might provide some clues for further study in cancer.

•

Describe the basics of TGF-β and BMP signalling

•

Summarize the potential mechanisms accounting for the antagonism between TGF-β and BMP pathways

•

Provide some evidence about the antagonistic effects between pathways observed in some cancers

Expression of bone morphogenetic protein 6 in non-small cell lung cancer and its significance

The present study investigated the expression and clinical significance of bone morphogenetic protein 6 (BMP-6) in patients with non-small cell lung cancer (NSCLC). The tumor and adjacent normal lung tissues were harvested from 65 patients with NSCLC. BMP-6 mRNA expression was measured by reverse transcription-quantitative polymerase chain reaction, while protein expression was measured using immunohistochemistry or an ELISA. Cell viability was determined using Cell Counting Kit-8. The association of BMP-6 mRNA expression with the prognosis of patients with NSCLC was analyzed using the Kaplan-Meier plotter database. BMP-6 mRNA expression in NSCLC tumor tissues was significantly reduced, compared with the adjacent normal lung tissues (P<0.001), yet no significant differences were observed between patients with different clinicopathological features (P>0.05). The expression level of BMP-6 protein in NSCLC tumor tissues was significantly reduced, compared with the adjacent normal lung tissues (P<0.05). Analysis with the Kaplan-Meier plotter database revealed that patients with NSCLC with low BMP-6 mRNA expression had a reduced overall survival rate (P<0.01). The active BMP6 protein significantly inhibited cell proliferation in H460, H1299, A549 and H520 cells. In conclusion, BMP-6 is a tumor suppressor in lung cancer and loss of BMP-6 expression is significantly associated with a poor prognosis in patients with NSCLC.

Biological effects of BMP7 on small-cell lung cancer cells and its bone metastasis

Small-cell lung cancer (SCLC) is typically fatal if untreated. It is characterized by early and widespread metastases, and has the ability to rapidly develop resistance to chemotherapy. Bone morphogenetic protein 7 (BMP7), a member of the BMP family of signaling molecules, has been implicated in various types of cancer, particularly prostate cancer and breast cancer. However, there is little knowledge of the function of BMP7 in SCLC. The aim of the present study was to investigate the biological function of recombinant human (rh)BMP7 on SCLC cells and the underlying molecular basis for this regulatory mechanism. The effect of rhBMP7 on SCLC cell lines and associated signaling pathways was investigated. Results suggested that rhBMP7 significantly inhibited the proliferation, motility and invasion of SBC-3 and SBC-5 cells. However, rhBMP7 exhibited no effect on the apoptosis of SBC-5 cells, but promoted apoptosis of SBC-3 cells. Furthermore, cell cycle analysis revealed that rhBMP7 was able to increase the proportion of cells in G1 phase and decrease the S phase proportion. Total and membrane BMP receptor (BMPR)IA and BMPRIB were highly expressed in SBC-5 cells, whereas cytoplasmic BMPRIA and BMPRIB expression was higher in SBC-3 cells. However, activin A receptor type I expression was higher in SBC-3 cells in total and cytoplasmic proteins. Furthermore, following stimulation with rhBMP7, Smad2, Smad4 and p21 were downregulated. We hypothesized that rhBMP7 inhibited the progressiveness of SCLC cells by inducing G1 phase arrest and inhibiting S phase entry. The results of the present study indicated that BMP7 serves a key function in regulating the progression of SCLC.

Bone Cell Activity in Clinical Prostate Cancer Bone Metastasis and Its Inverse Relation to Tumor Cell Androgen Receptor Activity

Advanced prostate cancer frequently metastasizes to bone and induces a mixed osteoblastic/osteolytic bone response. Standard treatment for metastatic prostate cancer is androgen-deprivation therapy (ADT) that also affects bone biology. Treatment options for patients relapsing after ADT are limited, particularly in cases where castration-resistance does not depend on androgen receptor (AR) activity. Patients with non-AR driven metastases may, however, benefit from therapies targeting the tumor microenvironment. Therefore, the current study specifically investigated bone cell activity in clinical bone metastases in relation to tumor cell AR activity, in order to gain novel insight into biological heterogeneities of possible importance for patient stratification into bone-targeting therapies. Metastasis tissue obtained from treatment-naïve (n = 11) and castration-resistant (n = 28) patients was characterized using whole-genome expression analysis followed by multivariate modeling, functional enrichment analysis, and histological evaluation. Bone cell activity was analyzed by measuring expression levels of predefined marker genes representing osteoclasts (ACP5, CTSK, MMP9), osteoblasts (ALPL, BGLAP, RUNX2) and osteocytes (SOST). Principal component analysis indicated a positive correlation between osteoblast and osteoclast activity and a high variability in bone cell activity between different metastases. Immunohistochemistry verified a positive correlation between runt-related transcription factor 2 (RUNX2) positive osteoblasts and tartrate-resistant acid phosphatase (TRAP, encoded by ACP5) positive osteoclasts lining the metastatic bone surface. No difference in bone cell activity was seen between treatment-naïve and castration-resistant patients. Importantly, bone cell activity was inversely correlated to tumor cell AR activity (measured as AR, FOXA1, HOXB13, KLK2, KLK3, NKX3-1, STEAP2, and TMPRSS2 expression) and to patient serum prostate-specific antigen (PSA) levels. Functional enrichment analysis indicated high bone morphogenetic protein (BMP) signaling in metastases with high bone cell activity and low tumor cell AR activity. This was confirmed by BMP4 immunoreactivity in tumor cells of metastases with ongoing bone formation, as determined by histological evaluation of van Gieson-stained sections. In conclusion, the inverse relation observed between bone cell activity and tumor cell AR activity in prostate cancer bone metastasis may be of importance for patient response to AR and/or bone targeting therapies, but needs to be evaluated in clinical settings in relation to serum markers for bone remodeling, radiography and patient response to therapy. The importance of BMP signaling in the development of sclerotic metastasis lesions deserves further exploration.

Opposing roles of TGFβ and BMP signaling in prostate cancer development

SMAD4 constrains progression of Pten-null prostate cancer and serves as a common downstream node of transforming growth factor β (TGFβ) and bone morphogenetic protein (BMP) pathways. Here, we dissected the roles of TGFβ receptor II (TGFBR2) and BMP receptor II (BMPR2) using a Pten-null prostate cancer model. These studies demonstrated that the molecular actions of TGFBR2 result in both SMAD4-dependent constraint of proliferation and SMAD4-independent activation of apoptosis. In contrast, BMPR2 deletion extended survival relative to Pten deletion alone, establishing its promoting role in BMP6-driven prostate cancer progression. These analyses reveal the complexity of TGFβ-BMP signaling and illuminate potential therapeutic targets for prostate cancer.

Emerging roles of the bone morphogenetic protein pathway in cancer: potential therapeutic target for kinase inhibition

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-β (TGF-β) family signalling pathway. Similar to TGF-β, the complex roles of BMPs in development and disease are demonstrated by their dichotomous roles in various cancers and cancer stages. Although early studies implicated BMP signalling in tumour suppressive phenotypes, the results of more recent experiments recognize BMPs as potent tumour promoters. Many of these complexities are becoming illuminated by understanding the role of BMPs in their contextual role in unique cell types of cancer and the impact of their surrounding tumour microenvironment. Here we review the emerging roles of BMP signalling in cancer, with a focus on the molecular underpinnings of BMP signalling in individual cancers as a valid therapeutic target for cancer prevention and treatment.

Activation of the pro-migratory bone morphogenetic protein receptor 1B gene in human MDA-MB-468 triple-negative breast cancer cells that over-express CYP2J2

Secondary metastases are the leading cause of mortality in patients with breast cancer. Cytochrome P450 (CYP) 2J2 (CYP2J2) is upregulated in many human tumors and generates epoxyeicosanoids from arachidonic acid that promote tumorigenesis and metastasis, but at present there is little information on the genes that mediate these actions. In this study MDA-MB-468 breast cancer cells were stably transfected with CYP2J2 (MDA-2J2 cells) and Affymetrix microarray profiling was undertaken. We identified 182 genes that were differentially expressed in MDA-2J2 cells relative to control (MDA-CTL) cells (log[fold of control] ≥2). From gene ontology pathway analysis bone morphogenetic protein (BMP) receptor 1B (BMPR1B) emerged as an important upregulated gene in MDA-2J2 cells. Addition of the BMPR1B ligand BMP2 stimulated the migration of MDA-2J2 cells, but not MDA-CTL cells, from 3D-matrigel droplets. Migration of MDA-2J2 cells was prevented by the BMPR antagonist dorsomorphin. These findings indicate that over-expression of CYP2J2 in MDA-MB-468-derived breast cancer cells activates BMPR1B expression that may contribute to increased migration. Targeting BMPR1B may be a novel approach to inhibit the metastatic activity of breast cancers that contain high levels of CYP2J2.

TGF-beta receptor mediated telomerase inhibition, telomere shortening and breast cancer cell senescence

Human telomerase reverse transcriptase (hTERT) plays a central role in telomere lengthening for continuous cell proliferation, but it remains unclear how extracellular cues regulate telomerase lengthening of telomeres. Here we report that the cytokine bone morphogenetic protein-7 (BMP7) induces the hTERT gene repression in a BMPRII receptor- and Smad3-dependent manner in human breast cancer cells. Chonic exposure of human breast cancer cells to BMP7 results in short telomeres, cell senescence and apoptosis. Mutation of the BMPRII receptor, but not TGFbRII, ACTRIIA or ACTRIIB receptor, inhibits BMP7-induced repression of the hTERT gene promoter activity, leading to increased telomerase activity, lengthened telomeres and continued cell proliferation. Expression of hTERT prevents BMP7-induced breast cancer cell senescence and apoptosis. Thus, our data suggest that BMP7 induces breast cancer cell aging by a mechanism involving BMPRII receptor- and Smad3-mediated repression of the hTERT gene.

Effect of recombinant human bone morphogenetic protein-2 on a novel lung cancer spine metastasis model in rodents

Lung cancer is the second most prevalent cancer. Spinal metastases are found in 30-90% of patients with death attributed to cancer. Due to bony destruction caused by metastases, surgical intervention is often required to restore spinal alignment and stability. While some research suggests that BMP-2 may possess tumorigenic effects, other studies show possible inhibition of cancer growth. Thirty-six athymic rats underwent intraosseous injection of lung adenocarcinoma cells into the L5 vertebral body. Cells were pre-treated with vehicle control (Group A) or rhBMP-2 (Group B) prior to implantation. At 4 weeks post-implantation, in vivo bioluminescent imaging (BLI) was performed to confirm presence of tumor and quantify signal. Plain radiographs and microComputed Tomography (microCT) were employed to establish and quantitate osteolysis. Histological analysis characterized pathologic changes in the vertebral body. At 4 weeks post-implantation, BLI showed focal signal in the L5 vertebral body in 93% of Group A animals and 89% of Group B animals. Average tumor burden by BLI radiance was 7.43 × 10(3)  p/s/cm(2) /sr (Group A) and 1.11 × 10(4)  p/s/cm(2) /sr (Group B). Radiographs and microCT demonstrated osteolysis in 100% of animals showing focal BLI signal. MicroCT demonstrated significant bone loss in both groups compared to age-matched controls but no difference between study groups. Histological analysis confirmed tumor invasion in the L5 vertebral body. These findings provide a reliable in vivo model to study isolated spinal metastases from lung cancer. Statement of Clinical Significance: The data support the notion that exposure to rhBMP-2 does not promote the growth of A549 lung cancer spine lesions. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1274-1281, 2016.

Bone Morphogenetic Proteins

Bone morphogenetic proteins (BMPs), originally identified as osteoinductive components in extracts derived from bone, are now known to play important roles in a wide array of processes during formation and maintenance of various organs including bone, cartilage, muscle, kidney, and blood vessels. BMPs and the related "growth and differentiation factors" (GDFs) are members of the transforming growth factor β (TGF-β) family, and transduce their signals through type I and type II serine-threonine kinase receptors and their intracellular downstream effectors, including Smad proteins. Furthermore, BMP signals are finely tuned by various agonists and antagonists. Because deregulation of the BMP activity at multiple steps in signal transduction is linked to a wide variety of human diseases, therapeutic use of activators and inhibitors of BMP signaling will provide potential avenues for the treatment of the human disorders that are caused by hypo- and hyperactivation of BMP signals, respectively.

Bone morphogenetic protein signaling in musculoskeletal cancer

PURPOSE

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-β (TGF-β) superfamily of proteins; they were initially named after their ability to induce ectopic bone formation. Published studies have proved BMPs' role in a variety of biological processes such as embryogenesis and patterning of body axes, and maintaining adult tissue homeostasis. Other studies have focused on BMPs properties, functions and possible involvement in skeletal diseases, including cancer.

METHODS

A literature search mainly paying attention to the role of BMPs in musculoskeletal tumors was performed in electronic databases.

RESULTS

This article discusses BMPs synthesis and signaling, and summarizes their prominent roles in the skeletal system for the differentiation of osteoblasts, osteocytes and chondrocytes.

CONCLUSIONS

The review emphasizes on the role of BMP signaling in the initiation and progression of musculoskeletal cancer.

Effect of siRNA mediated bone morphogenetic protein 7 knockdown on cell proliferation and migration in human hepatoma cell line HepG2

AIM: To investigate the effect of small interfering RNA (siRNA) mediated bone morphogenetic protein 7 (BMP7) knockdown on the proliferation and migration of human hepatoma HepG2 cells.

METHODS: Three pairs of siRNAs targeting BMP7 were transiently transfected into HepG2 cells using TransLipid HL Transfection Reagent. HepG2 cells were divided into five groups including a normal control group, a negative-siRNA group and three transfected groups (transfected with BMP7-siRNA-1, BMP7-siRNA-2, and BMP7-siRNA-3, respectively). The expression of BMP7 mRNA and protein was measured by reverse transcript-polymerase chain reaction (RT-PCR) and Western blot, respectively, and the optimal siRNA sequence for BMP7 silencing was selected. The proliferation and migration of HepG2 cells after transfection were assessed by MTT assay and transwell migration assay, respectively. The expression of apoptosis-related proteins (Bax, Bcl-2, and Caspase3) in each group was determined by Western blot, and the cell cycle was analyzed by flow cytometry.

RESULTS: BMP7-siRNA-3 group demonstrated the lowest level of BMP7 expression among the five groups (P < 0.01). Cell growth was significantly slower in the BMP7-siRNA-3 group than in the control groups 48 h and 72 h after cells were transfected (P < 0.01). The numbers of cell passing the membrane were significantly lower in the BMP7-siRNA-3 group than in the control groups 24 h after cells were transfected (P < 0.01). The expression of Bax and Caspase3 (P < 0.01) was significantly increased after BMP7 silencing, and there was no statistically significant difference in the Bcl-2 expression. Flow cytometery showed that cells were significantly blocked in G₂ phase 48 h after cells were transfected with BMP7-siRNA-3 (P < 0.01).

CONCLUSION: SiRNA mediated BMP7 knockdown can inhibit HepG2 cell proliferation and migration, promote apoptosis and block cells in G₂ phase.

Bone morphogenetic proteins in tumour associated angiogenesis and implication in cancer therapies

Bone morphogenetic protein (BMP) belongs to transforming growth factor-β superfamily. To date, more than 20 BMPs have been identified in humans. BMPs play a critical role in embryonic and postnatal development, and also in maintaining homeostasis in different organs and tissues by regulating cell differentiation, proliferation, survival and motility. They play important roles in the development and progression of certain malignancies, including prostate cancer, breast cancer, lung cancer, etc. Recently, more evidence shows that BMPs are also involved in tumour associated angiogenesis. For example BMP can either directly regulate the functions of vascular endothelial cells or indirectly influence the angiogenesis via regulation of angiogenic factors, such as vascular endothelial growth factor (VEGF). Such crosstalk can also be reflected in the interaction with other angiogenic factors, like hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF). All these factors are involved in the orchestration of the angiogenic process during tumour development and progression. Review of the relevant studies will provide a comprehensive prospective on current understanding and shed light on the corresponding therapeutic opportunity.

Mechanisms of action of bone morphogenetic proteins in cancer

The bone morphogenetic proteins (BMPs) play fundamental roles in embryonic development and control differentiation of a diverse set of cell types. It is therefore of no surprise that the BMPs also contribute to the process of tumourigenesis and regulate cancer progression through various stages. We summarise here key roles of BMP ligands, receptors, their signalling mediators, mainly focusing on proteins of the Smad family, and extracellular antagonists, that contribute to the onset of tumourigenesis and to cancer progression in diverse tissues. Overall, the BMP pathways seem to act as tumour suppressors that maintain physiological tissue homeostasis and which are perturbed in cancer either via genetic mutation or via epigenetic misregulation of key gene components. BMPs also control the self-renewal and fate choices made by stem cells in several tissues. By promoting cell differentiation, including inhibition of the process of epithelial-mesenchymal transition, BMPs contribute to the malignant progression of cancer at advanced stages. It is therefore reasonable that pharmaceutical industries continuously develop biological agents and chemical modulators of BMP signalling with the aim to improve therapeutic regimes against several types of cancer.

The BMP signaling pathway leads to enhanced proliferation in serous ovarian cancer-A potential therapeutic target

Members of the transforming growth factor-β (TGF-β) superfamily transduce signals via SMAD proteins. SMAD2 and SMAD3 mediate TGF-β signaling, whereas SMAD1, SMAD5, and SMAD8/9 transduce bone morphogenetic protein (BMP) signals. We would like to identify the function of BMP/SMAD5 signaling in serous ovarian cancer. The protein levels of total SMAD5 and phosphorylated SMAD5 (pSMAD5) were examined by immunohistochemical analysis using clinical serous ovarian cancer samples. Following treatment with either recombinant BMP2 (rBMP2) or Dorsomorphin (DM), western blotting was performed to observe pSMAD5 protein in the cytoplasm and the nucleus, separately. Cell proliferation was detected in SMAD5 knockdown serous ovarian cancer cell lines cultured with DM or rBMP2. The impact of DM or rBMP2 on tumor growth was observed in a mouse model of serous ovarian cancer. An inverse correlation was observed between pSMAD5 levels in the nucleus and the prognosis of patients with serous ovarian cancer. The treatment of SK-OV-3 with rBMP2 stimulated pSMAD5 translocation from the cytoplasm to the nucleus, and the addition of DM inhibited this effect. The proliferation of ovarian cancer cell lines was enhanced by BMP2 and suppressed by DM via SMAD5 in vitro. In vitro and in vivo experiments clearly demonstrated BMP2-stimulated proliferation of serous ovarian cancer and inhibition of this effect by DM. Our data suggests that BMP/SMAD5 signaling plays an important role and, therefore, becomes a potential therapeutic target in serous ovarian cancer. © 2015 Wiley Periodicals, Inc.

Upregulation of CRMP4, a new prostate cancer metastasis suppressor gene, inhibits tumor growth in a nude mouse intratibial injection model

Prostate cancer, the most commonly diagnosed male cancer in North America, has a high incidence of bone metastasis. Our previous study showed collapsin response mediator protein 4 (CRMP4) gene inhibited prostate cancer migration and invasion. In this study, we investigated whether overexpression of CRMP4 gene in prostate cancer cells inhibit tumor bone metastasis. The stable prostate cancer cells overexpressing the CRMP4 gene were constructed using lentivirus infection. Prostate cancer bone metastasis nude mouse model was built though orthotopic prostate implantation, intracardiac injection and intratibial injection with CRMP4 overexpress and control cancer cells. Small animal PET/CT scanning results showed no difference of bone metastatic capacity in orthotopic and intracardiac injection models between CRMP4 overexpression and control group, while CRMP4 overexpression inhibited tumor growth in the intratibial injection model. Moreover, our in vitro study showed CRMP4 overexpression downregulates the Neuropilin1 (NRP1) expression and upregulate the Noggin expression. Immunohistochemical staining of the hind limbs of intratibial injection model was confirmed with cytological experiments. Taken together, our research indicated CRMP4 inhibits prostate cancer cells growth in the nude mouse bone microenvironment and this effect may relate with regulation of NRP1 and Noggin expression.

CD44 and hyaluronan promote the bone morphogenetic protein 7 signaling response in murine chondrocytes

OBJECTIVE

Cell-matrix interactions promote cartilage homeostasis. We previously found that Smad1, the transcriptional modulator of the canonical bone morphogenetic protein 7 (BMP-7) pathway, interacted with the cytoplasmic domain of CD44, the principal hyaluronan receptor on chondrocytes. To elucidate the physiologic function of CD44-Smad1 interactions, as well as the role of hyaluronan, we studied the response of chondrocytes isolated from CD44(-/-) and BALB/c (wild-type [WT]) mice to stimulation with BMP-7.

METHODS

In primary murine chondrocytes, CD44 expression was decreased by small interfering RNA (siRNA) transfection or was enhanced by plasmid transfection. Pericellular hyaluronan was removed by hyaluronidase treatment, or its endogenous synthesis was inhibited. Changes in response to BMP-7 stimulation were evaluated by Western blotting of Smad1 phosphorylation and aggrecan messenger RNA (mRNA) expression.

RESULTS

Chondrocytes from CD44(-/-) mice and WT mice transfected with CD44 siRNA were less responsive than untransfected chondrocytes from WT mice to BMP-7. CD44(-/-) mouse chondrocytes transfected with pCD44 showed increased sensitivity to BMP-7. Significant increases in aggrecan mRNA were observed in WT mouse chondrocytes in response to 10 ng/ml of BMP-7, whereas at least 100 ng/ml of BMP-7 was required for CD44(-/-) mouse chondrocytes. However, in chondrocytes from CD44(-/-) and WT mice, hyaluronidase treatment decreased cellular responses to BMP-7. Treatment of both bovine and murine chondrocytes with 4-methylumbelliferone to reduce the synthesis of endogenous hyaluronan confirmed that hyaluronan promoted BMP-7 signaling.

CONCLUSION

Taken together, these investigations into the mechanisms underlying BMP-7 signaling in chondrocytes revealed that while hyaluronan-dependent pericellular matrix is critical for BMP-7 signaling, the expression of CD44 promotes the cellular response to lower concentrations of BMP-7.

BMP9 inhibits the bone metastasis of breast cancer cells by downregulating CCN2 (connective tissue growth factor, CTGF) expression

Bone morphogenetic proteins (BMPs), which belong to the transforming growth factor-β superfamily, regulate a wide range of cellular responses including cell proliferation, differentiation, adhesion, migration, and apoptosis. BMP9, the latest BMP to be discovered, is reportedly expressed in a variety of human carcinoma cell lines, but the role of BMP9 in breast cancer has not been fully clarified. In a previous study, BMP9 was found to inhibit the growth, migration, and invasiveness of MDA-MB-231 breast cancer cells. In the current study, the effect of BMP9 on the bone metastasis of breast cancer cells was investigated. After absent or low expression of BMP9 was detected in the MDA-MB-231 breast cancer cells and breast non-tumor adjacent tissues using Western blot and immunohistochemistry, In our previous study, BMP9 could inhibit the proliferation and invasiveness of breast cancer cells MDA-MB-231 in vitro and in vivo. This paper shows that BMP9 inhibit the bone metastasis of breast cancer cells by activating the BMP/Smad signaling pathway and downregulating connective tissue growth factor (CTGF); however, when CTGF expression was maintained, the inhibitory effect of BMP9 on the MDA-MB-231 cells was abolished. Together, these observations indicate that BMP9 is an important mediator of breast cancer bone metastasis and a potential therapeutic target for treating this deadly disease.

Contextual effect of repression of bone morphogenetic protein activity in prostate cancer

Several studies have focused on the effect of bone morphogenetic protein (BMP) on prostate cancer homing and growth at distant metastatic sites, but very little effect at the primary site. Here, we used two cell lines, one (E8) isolated from a primary tumor and the other (cE1) from a recurrent tumor arising at the primary site, both from the conditional Pten deletion mouse model of prostatic adenocarcinoma. Over-expression of the BMP antagonist noggin inhibited proliferation of cE1 cells in vitro while enhancing their ability to migrate. On the other hand, cE1/noggin grafts grown in vivo showed a greater mass and a higher proliferation index than the cE1/control grafts. For suppression of BMP activity in the context of cancer-associated fibroblasts (CAFs), we used noggin-transduced CAFs from the same mouse model to determine their effect on E8- or cE1-induced tumor growth. CAF/noggin led to increased tumor mass and greater de-differentiation of the E8 cell when compared with tumors formed in the presence of CAF/control cells. A trend of increase in the size of the tumor was also noted for cE1 cells when inoculated with CAF/noggin. Together, the results may point to a potential inhibitory role of BMP in the growth or re-growth of prostate tumor at the primary site. Additionally, results for cE1/noggin, and cE1 mixed with CAF/noggin, suggested that suppression of BMP activity in the cancer cells may have a stronger growth-enhancing effect on the tumor than its suppression in the fibroblastic compartment of the tumor microenvironment.

Endoglin-mediated suppression of prostate cancer invasion is regulated by activin and bone morphogenetic protein type II receptors

Mortality from prostate cancer (PCa) is due to the formation of metastatic disease. Understanding how that process is regulated is therefore critical. We previously demonstrated that endoglin, a type III transforming growth factor β (TGFβ) superfamily receptor, suppresses human PCa cell invasion and metastasis. Endoglin-mediated suppression of invasion was also shown by us to be dependent upon the type I TGFβ receptor, activin receptor-like kinase 2 (ALK2), and the downstream effector, Smad1. In this study we demonstrate for the first time that two type II TGFβ receptors are required for endoglin-mediated suppression of invasion: activin A receptor type IIA (ActRIIA) and bone morphogenetic protein receptor type II (BMPRII). Downstream signaling through these receptors is predominantly mediated by Smad1. ActRIIA stimulates Smad1 activation in a kinase-dependent manner, and this is required for suppression of invasion. In contrast BMPRII regulates Smad1 in a biphasic manner, promoting Smad1 signaling through its kinase domain but suppressing it through its cytoplasmic tail. BMPRII’s Smad1-regulatory effects are dependent upon its expression level. Further, its ability to suppress invasion is independent of either kinase function or tail domain. We demonstrate that ActRIIA and BMPRII physically interact, and that each also interacts with endoglin. The current findings demonstrate that both BMPRII and ActRIIA are necessary for endoglin-mediated suppression of human PCa cell invasion, that they have differential effects on Smad1 signaling, that they make separate contributions to regulation of invasion, and that they functionally and physically interact.

Loss of survivin in the prostate epithelium impedes carcinogenesis in a mouse model of prostate adenocarcinoma

The inhibitor of apoptosis protein survivin is expressed in most cancers. Using the conditional PTEN deletion mouse model, we previously reported that survivin levels increase with prostate tumor growth. Here we evaluated the functional role of survivin in prostate tumor growth. First, we demonstrated that mice lacking the survivin gene in prostate epithelium were fertile and had normal prostate growth and development. We then serially, from about 10-56 weeks of age, evaluated histopathologic changes in the prostate of mice with PTEN deletion combined with survivin mono- or bi-allelic gene deletion. While within this time period most of the animals with wild-type or monoallelic survivin deletion developed adenocarcinomas, the most severe lesions in the biallelic survivin deleted mice were high-grade prostatic intra-epithelial neoplasia with distinct histopathology. Many atypical cells contained large hypertrophic cytoplasm and desmoplastic reaction in the prostatic intra-epithelial neoplasia lesions of this group was minimal until the late ages. A reduced proliferation index as well as apoptotic and senescent cells were detected in the lesions of mice with compound PTEN/survivin deficiency throughout the time points examined. Survivin deletion was also associated with reduced tumor expression of another inhibitor of apoptosis member, the X-linked inhibitor of apoptosis. Our findings suggest that survivin participates in the progression of prostatic intraepithelial neoplasia to adenocarcinoma, and that survivin interference at the prostatic intraepithelial neoplasia stages may be a potential therapeutic strategy to halt or delay further progression.

Bone Morphogenetic Proteins stimulate mammary fibroblasts to promote mammary carcinoma cell invasion

Bone Morphogenetic Proteins (BMPs) are secreted cytokines that are part of the Transforming Growth Factor β (TGFβ) superfamily. BMPs have been shown to be highly expressed in human breast cancers, and loss of BMP signaling in mammary carcinomas has been shown to accelerate metastases. Interestingly, other work has indicated that stimulation of dermal fibroblasts with BMP can enhance secretion of pro-tumorigenic factors. Furthermore, treatment of carcinoma-associated fibroblasts (CAFs) derived from a mouse prostate carcinoma with BMP4 was shown to stimulate angiogenesis. We sought to determine the effect of BMP treatment on mammary fibroblasts. A large number of secreted pro-inflammatory cytokines and matrix-metallo proteases (MMPs) were found to be upregulated in response to BMP4 treatment. Fibroblasts that were stimulated with BMP4 were found to enhance mammary carcinoma cell invasion, and these effects were inhibited by a BMP receptor kinase antagonist. Treatment with BMP in turn elevated pro-tumorigenic secreted factors such as IL-6 and MMP-3. These experiments demonstrate that BMP may stimulate tumor progression within the tumor microenvironment.

Bone Morphogenetic Proteins stimulate mammary fibroblasts to promote mammary carcinoma cell invasion

Bone Morphogenetic Proteins (BMPs) are secreted cytokines that are part of the Transforming Growth Factor β (TGFβ) superfamily. BMPs have been shown to be highly expressed in human breast cancers, and loss of BMP signaling in mammary carcinomas has been shown to accelerate metastases. Interestingly, other work has indicated that stimulation of dermal fibroblasts with BMP can enhance secretion of pro-tumorigenic factors. Furthermore, treatment of carcinoma-associated fibroblasts (CAFs) derived from a mouse prostate carcinoma with BMP4 was shown to stimulate angiogenesis. We sought to determine the effect of BMP treatment on mammary fibroblasts. A large number of secreted pro-inflammatory cytokines and matrix-metallo proteases (MMPs) were found to be upregulated in response to BMP4 treatment. Fibroblasts that were stimulated with BMP4 were found to enhance mammary carcinoma cell invasion, and these effects were inhibited by a BMP receptor kinase antagonist. Treatment with BMP in turn elevated pro-tumorigenic secreted factors such as IL-6 and MMP-3. These experiments demonstrate that BMP may stimulate tumor progression within the tumor microenvironment.

Overexpression of CD157 contributes to epithelial ovarian cancer progression by promoting mesenchymal differentiation

Epithelial ovarian carcinoma (EOC) is an aggressive tumor often diagnosed at an advanced stage, when there is little or no prospect of cure. Despite advances in surgical and chemotherapeutic strategies, only marginal improvements in patient outcome have been obtained. Hence, unraveling the biological mechanisms underpinning EOC progression is critical for improving patients’ survival. Recently, we reported that CD157 (an ectoenzyme regulating leukocyte diapedesis) is expressed in EOC and that high expression of the molecule is negatively correlated with the disease outcome in patients. Here, we demonstrate that forced overexpression of CD157 in OVCAR-3, TOV-21G, A2780 and OV-90 ovarian cancer cell lines promotes morphological and phenotypic changes characterized by disruption of intercellular junctions, downregulation of epithelial markers and upregulation of mesenchymal ones. These changes in cell shape and phenotype bring to reduced sensitivity to anoikis, increased anchorage-independent growth, cell motility and mesothelial invasion. Conversely, knockdown of CD157 in OV-90 and OC314 cells reverts the mesenchymal phenotype and reduces the cells’ migratory potential. Transcriptome profiling analysis highlighted 378 significantly differentially expressed genes, representing the signature of CD157-overexpressing OVCAR-3 and OV-90 cells. The modulation of selected genes translates into alteration of protein expression that give cells a highly malignant phenotype. The overall picture deduced from the analysis of the modulated transcripts is that high expression of CD157 strengthens a number of biological processes favoring tumor progression (including development and cell motility), and weakens several biological processes hindering tumor progression (such as apoptosis, cell death and response to stress). Together, these findings implicate CD157 in the progression of EOC to metastatic disease and suggest that CD157 may represent a valuable therapeutic target.

Prostate cancer cells and bone stromal cells mutually interact with each other through bone morphogenetic protein-mediated signals

Functional interactions between cancer cells and the bone microenvironment contribute to the development of bone metastasis. Although the bone metastasis of prostate cancer is characterized by increased ossification, the molecular mechanisms involved in this process are not fully understood. Here, the roles of bone morphogenetic proteins (BMPs) in the interactions between prostate cancer cells and bone stromal cells were investigated. In human prostate cancer LNCaP cells, BMP-4 induced the production of Sonic hedgehog (SHH) through a Smad-dependent pathway. In mouse stromal MC3T3-E1 cells, SHH up-regulated the expression of activin receptor IIB (ActR-IIB) and Smad1, which in turn enhanced BMP-responsive reporter activities in these cells. The combined stimulation with BMP-4 and SHH of MC3T3-E1 cells cooperatively induced the expression of osteoblastic markers, including alkaline phosphatase, bone sialoprotein, collagen type II α1, and osteocalcin. When MC3T3-E1 cells and LNCaP cells were co-cultured, the osteoblastic differentiation of MC3T3-E1 cells, which was induced by BMP-4, was accelerated by SHH from LNCaP cells. Furthermore, LNCaP cells and BMP-4 cooperatively induced the production of growth factors, including fibroblast growth factor (FGF)-2 and epidermal growth factor (EGF) in MC3T3-E1 cells, and these may promote the proliferation of LNCaP cells. Taken together, our findings suggest that BMPs provide favorable circumstances for the survival of prostate cancer cells and the differentiation of bone stromal cells in the bone microenvironment, possibly leading to the osteoblastic metastasis of prostate cancer.

Delayed onset of paralysis and slowed tumor growth following in situ placement of recombinant human bone morphogenetic protein 2 within spine tumors in a rat model of metastatic breast cancer

Object

Recombinant human bone morphogenetic proteins (rhBMPs) are FDA-approved for specific spinal fusion procedures, but their use is contraindicated in spine tumor resection beds because of an unclear interaction between tumor tissue and such growth factors. Interestingly, a number of studies have suggested that BMPs may slow the growth of adenocarcinomas in vitro, and these lesions represent the majority of bony spine tumors. In this study, the authors hypothesized that rhBMP-2 placed in an intraosseous spine tumor in the rat could suppress tumor and delay the onset of paresis in such animals.

Methods

Twenty-six female nude athymic rats were randomized into an experimental group (Group 1) or a positive control group (Group 2). Group 1 (tumor + 15 μg rhBMP-2 sponge,13 rats) underwent transperitoneal exposure and implantation of breast adenocarcinoma (CRL-1666) into the L-6 spine segment, followed by the implantation of a bovine collagen sponge impregnated with 15 μg of rhBMP-2. Group 2 (tumor + 0.9% NaCl sponge, 13 rats) underwent transperitoneal exposure and tumor implantation in the lumbar spine but no local treatment with rhBMP-2. An additional 8 animals were randomized into 2 negative control groups (Groups 3 and 4). Group 3 (15 μg rhBMP-2 sponge, 4 rats) and Group 4 (0.9% NaCl sponge, 4 rats) underwent transperitoneal exposure of the lumbar spine along with the implantation of rhBMP-2– and saline-impregnated bovine collagen sponges, respectively. Neither of the negative control groups was implanted with tumor. The Basso-Beattie-Bresnahan (BBB) scale was used to monitor daily motor function regression and the time to paresis (BBB score ≤ 7).

Results

In comparison with the positive control animals (Group 2), the experimental animals (Group 1) had statistically significant longer mean (25.8 ± 12.2 vs 13 ± 1.4 days, p ≤ 0.001) and median (20 vs 13 days) times to paresis. In addition, the median survival time was significantly longer in the experimental animals (20 vs 13.5 days, p ≤ 0.0001). Histopathological analysis demonstrated bone growth and tumor inhibition in the experimental animals, whereas bone destruction and cord compression were observed in the positive control animals. Neither of the negative control groups (Groups 3 and 4) demonstrated any evidence of neurological deterioration, morbidity, or cord compromise on either gross or histological analysis.

Conclusions

This study shows that the local administration of rhBMP-2 (15 μg, 10 μl of 1.5-mg/ml solution) in a rat spine tumor model of breast cancer not only fails to stimulate local tumor growth, but also decreases local tumor growth and delays the onset of paresis in rats. This preclinical experiment is the first to show that the local placement of rhBMP-2 in a spine tumor bed may slow tumor progression and delay associated neurological decline.

PI3K, Erk signaling in BMP7-induced epithelial-mesenchymal transition (EMT) of PC-3 prostate cancer cells in 2- and 3-dimensional cultures

We reported previously that bone morphogenetic protein 7 (BMP7) could induce epithelial-mesenchymal transition (EMT) in PC-3 prostate cancer cells grown in tissue culture plates. In this study, we examined BMP7-induced morphological and molecular expression changes that are characteristic of EMT using these cells under both two- (2D) and three-dimensional (3D) culture conditions. Filamentous outgrowths from spheroid structures that were formed from PC-3 cells in 3D cultures were strikingly evident when the spheroids were exposed to extracellular BMP7. This morphological change in 3D was accompanied by down-regulation of E-cadherin, which is an essential adhesion molecule for the integrity of epithelial phenotype. Invasiveness of the cancer cells was significantly enhanced with BMP7 treatment along with activation and up-regulation of proteases such as MMP1, MMP13, and urokinase plasminogen activator. Signal transduction of EMT conversion was examined by the use of certain pathway-specific inhibitors. Of the chemical inhibitors tested, inhibitors of PI3 kinase and Erk were found to suppress BMP-induced morphological changes both in 2D and 3D conditions. These results suggest that, besides the Smad signaling pathways, BMP-induced activation of PI3K and Erk contribute to EMT morphologic conversion of the PC-3 prostate cancer cells. Together, the results support the notion that the complexity of EMT may be better evaluated in terms of both spatial and temporal processes in 3D cell culture models that are physiologically more relevant than the cell growth in tissue culture plates.

Augmented autocrine bone morphogenic protein (BMP) 7 signaling increases the metastatic potential of mouse breast cancer cells

As malignant breast cancers progress, they acquire the ability to spread to other regions of the body, including bone and lung, but the molecular mechanism underlying the increase in metastatic potential is not fully understood. Here we studied murine 4T1E/M3 highly bone marrow metastatic breast cancer cells, which we established previously. These cells show upregulated expression of bone morphogenetic protein (BMP) 7 and BMP receptors, as well as augmented phosphorylation of Smad1/5/8. Both anchorage-independent cell growth measured in colony forming assays and cell migration measured in wound healing assays were suppressed in 4T1E/M3 cells following treatment with a neutralizing anti-BMP7 antibody or knockdown of BMP7 gene expression. In addition, metastasis of 4T1E/M3 cells to the spine and lung and intracellular levels of phosphorylated Smad1/5/8 were suppressed by knocking down BMP7. Conversely, overexpression of BMP7 in the weakly metastatic parental 4T1E cells augmented their anchorage-independent growth, migration and metastasis to spine and lung. Taken together, our results strongly suggest that augmented autocrine BMP7 signaling leads to increases in the anchorage-independent cell growth, migration and metastatic potential in our bone marrow metastatic breast cancer model.

Effect of bone morphogenetic protein-2 on proliferation and apoptosis of gastric cancer cells

OBJECTIVE

To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells.

METHODS

Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4).

RESULTS

BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin.

CONCLUSIONS

BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.

Bone morphogenetic protein modulator BMPER is highly expressed in malignant tumors and controls invasive cell behavior

Bone morphogenetic proteins (BMPs) are growth factors that exert important functions in cell proliferation, migration and differentiation. Till date, multiple human tumors have been reported to display a dysregulation of several members of the BMP pathway that is associated with enhanced malignant tumor growth and metastasis. BMPER (BMP endothelial cell precursor-derived regulator) is a direct BMP modulator that is necessary for BMPs to exert their full-range signaling activity. Moreover, BMPER is expressed by endothelial cells and their progenitors, and has pro-angiogenic features in these cells. Here, we describe the expression of BMPER in human specimens of lung, colon and cervix carcinomas and cell lines derived from such carcinomas. In contrast to healthy tissues, BMPER is highly expressed upon malignant deterioration. Functionally, loss of BMPER in the lung tumor cell line A549 impairs proliferation, migration, invasion as well as tumor cell-induced endothelial cell sprout formation. In contrast, stimulation of A549 cells with exogenous BMPER had no further effect. We found that the BMPER effect may be transduced by regulation of the BMP target transcription factor inhibitor of DNA binding 1 (Id1) and matrix metalloproteinases (MMPs) 9 and 2. These facilitators of cell migration are downregulated when BMPER is absent. To prove the relevance of our in vitro results in vivo, we generated Lewis lung carcinoma cells with impaired BMPER expression and implanted them into the lungs of C57BL/6 mice. In this model, the absence of BMPER resulted in severely reduced tumor growth and tumor angiogenesis. Taken together, these data unequivocally demonstrate that the BMP modulator BMPER is highly expressed in malignant tumors and tumor growth is dependent on the presence of BMPER.

Treatment effects of rhBMP-2 on invasiveness of oral carcinoma cell lines

OBJECTIVE

To determine if recombinant human bone morphogenetic protein-2 (rhBMP-2) has biological effects on the invasiveness of human oral squamous cell carcinoma (OSCCA) cell lines.

STUDY DESIGN

Laboratory investigation using six human OSCCA cell lines, with three cell lines having baseline gene expression of BMP-2 and three cell lines without baseline gene expression of BMP-2.

METHODS

The invasiveness of each cell line was measured using a matrigel invasion assay with or without stimulation by rhBMP-2. A tumor metastasis quantitative PCR array was used to establish whether observed findings from the invasion assay correlated to changes in gene expression.

RESULTS

There was a significant increase in tumor cell invasion in response to rhBMP-2 in all BMP-2 positive cell lines but no change in the cell lines that did not express the BMP-2 gene. Quantitative PCR revealed that changes in gene expression were distinctly different based on the baseline gene expression of BMP-2 and favored a more metastatic genotype in the BMP-2-positive cells.

CONCLUSIONS

Recombinant human BMP-2 has an adverse biological effect on invasiveness of human OSCCA cell lines in vitro. This adverse effect is dependent on the baseline gene expression of BMP-2. Changes in expression of genes involved with tumor metastasis correlated to the invasion assay findings. These data raise concern for the safe application of rhBMP-2 for reconstruction of bone defects in oral cancer patients.

Reactivation of embryonic nodal signaling is associated with tumor progression and promotes the growth of prostate cancer cells

BACKGROUND

Nodal is a member of the transforming growth factor β (TGFβ) superfamily that directs embryonic patterning and promotes the plasticity and tumorigenicity of tumor cells, but its role in the prostate is unknown. The goal of this study was to characterize the expression and function of Nodal in prostate cancer and determine whether, like other TGFβ ligands, it modulates androgen receptor (AR) activity.

METHODS

Nodal expression was investigated using immunohistochemistry of tissue microarrays and Western blots of prostate cell lines. The functional role of Nodal was examined using Matrigel and soft agar growth assays. Cross-talk between Nodal and AR signaling was assessed with luciferase reporter assays and expression of endogenous androgen regulated genes.

RESULTS

Significantly increased Nodal expression was observed in cancer compared with benign prostate specimens. Nodal was only expressed by DU145 and PC3 cells. All cell lines expressed Nodal's co-receptor, Cripto-1, but lacked Lefty, a critical negative regulator of Nodal signaling. Recombinant human Nodal triggered downstream Smad2 phosphorylation in DU145 and LNCaP cells, and stable transfection of pre-pro-Nodal enhanced the growth of LNCaP cells in Matrigel and soft agar. Finally, Nodal attenuated AR signaling, reducing the activity of a PSA promoter construct in luciferase assays and down-regulating the endogenous expression of androgen regulated genes.

CONCLUSIONS

An aberrant Nodal signaling pathway is re-expressed and functionally active in prostate cancer cells.

[BMP7 signaling via BMPR1A, BMPR1B inhibits the proliferation of lung large carcinoma NCI-H460 cell]

背景与目的

已有的研究发现骨形成蛋白7（bone morphogenetic protein 7, BMP7）具有抑制和促进多种肿瘤发生发展的双重作用，但其对肺癌细胞增殖的影响及其具体机制尚不明确。本实验首先检测了外源性BMP7对肺癌细胞增殖的影响，然后通过在肺癌细胞系中阻断不同的Ⅰ型受体，观察其对BMP7生物学作用的影响，以探讨不同的Ⅰ型受体在BMP7信号传导过程中的作用。

方法

应用RT-PCR及MTT方法分别检测4种非小细胞肺癌（non-small cell lung cancer, NSCLC）细胞系和人支气管上皮细胞系（HBE）中BMP7 Ⅰ型受体的表达情况及外源性BMP7对肺癌细胞增殖能力的影响，并联合运用抗体阻断的方法阻断NCI-H460细胞中内源性Ⅰ型抗体，采用MTT法检测BMP7对NCI-H460细胞增殖的影响，分析不同的Ⅰ型受体在BMP7信号传导过程中的作用。

结果

NCI-H460细胞系中三种Ⅰ型受体均有表达。外源性BMP7抑制了肺大细胞癌NCI-H460细胞的增殖（P=0.002）。运用特异性抗体阻断NCI-H460细胞内源性BMPR1A、BMPR1B、BMPR1A+BMPR1B后BMP7对NCI-H460增殖的抑制作用明显减弱（P=0.003, P=0.014, P < 0.001），而阻断ACVR1A后BMP7对NCI-H460增殖的抑制作用无明显变化（P=0.074）。

结论

BMP7通过激活BMPR1A、BMPR1B两种Ⅰ型受体抑制NCI-H460细胞的增殖。