Bone morphogenetic protein-4 abrogates lumen formation by mammary epithelial cells and promotes invasive growth

Genome-wide association study for milking speed in Fleckvieh cattle

Milking speed is an important trait influencing udder health of dairy cows as well as labor efficiency. Yet, it has received little attention in genomic association studies. The main objective of this study was to determine regions and genes on the genome with a potential effect on milking speed in Fleckvieh (dual purpose Simmental) cattle. Genome-wide association studies were conducted using de-regressed breeding values of bulls as phenotypes. Six SNP on 4 autosomes were significantly associated with milking speed for additive effects. Significant regions on BTA4 and BTA19 correspond with findings for other dairy cattle breeds. Based on the observation of Fleckvieh breed managers, variation of milking speed in batches of daughters of some bulls is much higher than in daughter groups of other bulls. This difference in within family variation may be caused by transmission of alternative alleles of bulls being heterozygous for a gene affecting milking speed. To check on this, we considered standard deviation of yield deviations in milking speed of half-sib daughters as a new trait and performed GWAS for dominance effects. One signal on BTA5 passed the genome wide Bonferroni threshold that corresponded to the significant signal from standard GWAS on de-regressed breeding values. The key conclusion of this study is that several strong genomic signals were found for milking speed in Fleckvieh cattle and that the strongest of them are supported by similar findings in Brown Swiss and Holstein Friesian cattle. Milking speed is a complex trait whose sub-processes have not yet been elucidated in detail. Hence, it remains a challenge to link the associated regions on the genome with causal genes and their functions.

Lysine (K)-specific demethylase 5C regulates the incidence of severe preeclampsia by adjusting the expression of bone morphogenetic protein-7

This study aimed to investigate the roles of the lysine (K)-specific demethylase 5C (KDM5C)-bone morphogenetic protein-7 (BMP-7) signaling pathway in the pathogenesis of severe preeclampsia (sPE). A total of 180 pregnant patients were enrolled in the study and classified into three groups: an early-onset sPE group (EOsPE) (n = 60), a late-onset sPE group (LOsPE) (n = 60), and a control group (normal pregnancy; n = 60). The messenger RNA (mRNA) and protein expression levels of bone morphogenetic protein receptor II (BMPRII), BMP-7, and KDM5C were detected in placenta samples from the two sPE groups, and their sites were evaluated using immunohistochemistry (IHC). The sPE groups showed an increased KDM5C mRNA expression, and the EOsPE group showed a decreased BMP-7 and BMPRII mRNA expression compared with the LOsPE group. However, contradictory results were discovered in terms of protein expression. Immunostaining of KDM5C, BMP-7, and BMPRII was observed in villous trophoblast and extravillous trophoblast cells. Compared with the control group, the staining intensity of KDM5C in the placental tissue trophoblast cell nucleus and vascular endothelial cells of the sPE groups was weaker, while that of BMP-7 and BMPRII was stronger, and the staining intensity was more subjective in the LOsPE group. Consistent findings were obtained by IHC and Western blot analysis. KDM5C nuclear-cytoplasmic translocation may regulate sPE through BMP-7 and its receptors. The KDM5C-BMP-7 signaling pathway may also lead to less invasion and increased apoptosis of the trophoblast cells, which is involved in the pathogenesis of sPE.

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.

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.

BMP-2 upregulates the AKT/mTOR pathway in breast cancer with microcalcification and indicates a poor prognosis

BACKGROUND

As a reliable biomarker of breast cancer, breast microcalcification has been reported to be correlated with poor prognosis. Bone morphogenetic protein 2 (BMP-2) plays an important role in microcalcification of breast cancer. Studies in other tissues have shown an association between BMP-2 and AKT/mTOR pathway, while their relationship in breast cancer still remains largely undetermined. To clarify the relationship of these three factors, we collected patients of invasive breast cancer with/without microcalcification and immunohistochemical examination was performed.

METHOD/PATIENTS

A total of 272 patients with primary invasive breast cancer were selected from the First Hospital of China Medical University from January 2010 to January 2012. Immunohistochemical examination of the BMP-2, p-AKT and p-mTOR was performed on 4-µm tissue microarray (TMA) sections. Then, we analyzed the relationship of BMP-2, p-AKT, and p-mTOR and their correlation with disease-free survival (DFS) in breast cancer with/without microcalcification.

RESULTS

We found that breast cancer patients with microcalcification were correlated with HER-2 positive expression and poor prognosis. Immunohistochemical examination showed that the expressions of BMP-2 and p-mTOR were increased in breast cancer with microcalcification and the expressions of BMP-2, p-AKT, and p-mTOR were correlated with each other. Moreover, the high expressions of BMP-2, p-AKT, and p-mTOR were significantly correlated with poor prognosis.

CONCLUSIONS

Based on the abovementioned findings, we hypothesized that the high expression of BMP-2 not only played a vital role in the formation of microcalcification, but also activated the AKT/mTOR pathway. Collectively, breast cancer patients with microcalcification were more likely to be resistant to targeted or endocrine therapy and be correlated with poor prognosis.

Propagation of functional estrogen receptor positive normal human breast cells in 3D cultures

PURPOSE

Understanding how differentiation, microenvironment, and hormonal milieu influence human breast cell susceptibility to malignant transformation will require the use of physiologically relevant in vitro systems. We sought to develop a 3D culture model that enables the propagation of normal estrogen receptor alpha (ER) + cells.

METHODS

We tested soluble factors and protocols for the ability to maintain progenitor and ER + cells in cultures established from primary cells. Optimized conditions were then used to profile estrogen-induced gene expression changes in cultures from three pathology-free individuals.

RESULTS

Long-term representation of ER + cells was optimal in medium that included three different TGFβ/activin receptor-like kinase inhibitors. We found that omitting the BMP signaling antagonist, Noggin, enhanced the responsiveness of the PGR gene to estradiol exposure without altering the proportions of ER + cells in the cultures. Profiling of estradiol-exposed cultures showed that while all the cultures showed immediate and robust induction of PGR, LRP2, and IGFB4, other responses varied qualitatively and quantitatively across specimens.

CONCLUSIONS

We successfully identified conditions for the maintenance and propagation of functional ER + cells from normal human breast tissues. We propose that these 3D cultures will overcome limitations of conventional 2D cultures of partially or fully transformed cell lines by sustaining normal endocrine function and growth regulation of the cell populations that comprise intact breasts.

Effect of Icariin on Engineered 3D-Printed Porous Scaffolds for Cartilage Repair

In recent times, cartilage defects have been the most common athletic injuries, often leading to dreadful consequences such as osteoarthritis, pain, joint deformities, and other symptoms. It is also evident that damage to articular cartilage is often difficult to recover or self-heal because of poor vascular, nervous, and lymphatic supplies. Moreover, cartilage cells have poor regeneration ability and high maturity. Inspired by these facts and the rapid advances in the field of tissue engineering (TE), we fabricated highly porous three-dimensional (3D) scaffold architectures based on cell-responsive polymeric inks, i.e., sodium alginate and gelatin (SA-Gel, 1:3 ratio), by a novel 3D printing method. Moreover, the effect of various processing parameters was systematically investigated. The printed scaffolds of polymer composites gels with excellent transparency, moderate viscosity, and excellent fluid properties showed good surface morphology, better thermal stability and swelling effect, and unique interconnected porous architectures at the optimized operating parameters. In vitro cell proliferation experiments of these cytocompatible scaffolds showed the excellent adhesion rate and growth behavior of chondrocytes. In addition, the porous architectures facilitated the efficient distribution of cells with only a few remaining on the surface, which was confirmed by confocal laser scanning microscopic (CLSM) observations. Icariin (ICA) addition at a concentration of 10 μg/mL further significantly enhanced the proliferation of chondrocytes. We envision that these cell-responsive polymeric inks in the presence of growth regulators like ICA may have potential in engineering complex tissue constructs toward diverse applications in TE.

TGF-β Family Signaling in Ductal Differentiation and Branching Morphogenesis

Epithelial cells contribute to the development of various vital organs by generating tubular and/or glandular architectures. The fully developed forms of ductal organs depend on processes of branching morphogenesis, whereby frequency, total number, and complexity of the branching tissue define the final architecture in the organ. Some ductal tissues, like the mammary gland during pregnancy and lactation, disintegrate and regenerate through periodic cycles. Differentiation of branched epithelia is driven by antagonistic actions of parallel growth factor systems that mediate epithelial-mesenchymal communication. Transforming growth factor-β (TGF-β) family members and their extracellular antagonists are prominently involved in both normal and disease-associated (e.g., malignant or fibrotic) ductal tissue patterning. Here, we discuss collective knowledge that permeates the roles of TGF-β family members in the control of the ductal tissues in the vertebrate body.

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

Bone morphogenetic proteins (BMPs) belong to the TGF-β super family, and are essential for the regulation of foetal development, tissue differentiation and homeostasis and a multitude of cellular functions. Naturally, this has led to the exploration of aberrance in this highly regulated system as a key factor in tumourigenesis. Originally identified for their role in osteogenesis and bone turnover, attention has been turned to the potential role of BMPs in tumour metastases to, and progression within, the bone niche. This is particularly pertinent to breast cancer, which commonly metastasises to bone, and in which studies have revealed aberrations of both BMP expression and signalling, which correlate clinically with breast cancer progression. Ultimately a BMP profile could provide new prognostic disease markers. As the evidence suggests a role for BMPs in regulating breast tumour cellular function, in particular interactions with tumour stroma and the bone metastatic microenvironment, there may be novel therapeutic potential in targeting BMP signalling in breast cancer. This review provides an update on the current knowledge of BMP abnormalities and their implication in the development and progression of breast cancer, particularly in the disease-specific bone metastasis.

Epithelial-mesenchymal transition in morphogenesis, cancer progression and angiogenesis

All organs consist of an epithelium and an associated mesenchyme, so these epithelial-mesenchymal intercations are among the most important phenomena in nature. The aim of this article is the summarize the common mechanisms involved in the establishment of epithelial mesenchymal transition in three biological processes, namely organogenesis, tumor progression and metastasis, and angiogenesis, apparently independent each from other. A common feature of these processes is the fact that specialized epithelial cells lose their features, including cell adhesion and polarity, reorganize their cytoskeleton, and acquire a mesenchymal morphology and the ability to migrate.

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.

A Molecular View of Pathological Microcalcification in Breast Cancer

Breast microcalcification is a potential diagnostic indicator for non-palpable breast cancers. Microcalcification type I (calcium oxalate) is restricted to benign tissue, whereas type II (calcium hydroxyapatite) occurs both in benign as well as in malignant lesions. Microcalcification is a pathological complication of the mammary gland. Over the past few decades, much attention has been paid to exploit this property, which forms the basis for advances in diagnostic procedures and imaging techniques. The mechanism of its formation is still poorly understood. Hence, in this paper, we have attempted to address the molecular mechanism of microcalcification in breast cancer. The central theme of this communication is "how a subpopulation of heterogeneous breast tumor cells attains an osteoblast-like phenotype, and what activities drive the process of pathophysiological microcalcification, especially at the invasive or infiltrating front of breast tumors". The role of bone morphogenetic proteins (BMPs) and tumor associated macrophages (TAMs) along with epithelial to mesenchymal transition (EMT) in manipulating this pathological process has been highlighted. Therefore, this review offers a novel insight into the mechanism underlying the development of microcalcification in breast carcinomas.

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.

N-cadherin mediates the migration of MCF-10A cells undergoing bone morphogenetic protein 4-mediated epithelial mesenchymal transition

Epithelial-mesenchymal transition (EMT) of mammary epithelial cells is important in both normal morphogenesis of mammary glands and metastasis of breast cancer. Cadherin switching from E-cadherin to N-cadherin plays important roles in EMT. We found that cadherin switching is important in bone morphogenetic protein 4 (BMP4)-induced EMT in MCF-10A cells. BMP4 increased the phosphorylation of SMAD proteins in MCF-10A cells. Canonical BMP4 signaling decreased the expression of E-cadherin and disrupted the polarity of the tight junction protein ZO-1 in MCF-10A cells. However, the expression of N-cadherin and SNAI2 was up-regulated in BMP4-treated MCF-10A cells. MCF-10A cells that expressed N-cadherin migrated into type I collagen gels in response to BMP4 when evaluated using three-dimensional culture assays. Thus, active canonical BMP4 signaling is important for the migration and EMT of mammary epithelial cells. Moreover, the decrease in E-cadherin and/or increase in N-cadherin may be required for BMP4-induced migration and EMT.

BMP4 inhibits the proliferation of breast cancer cells and induces an MMP-dependent migratory phenotype in MDA-MB-231 cells in 3D environment

Background

Bone morphogenetic protein 4 (BMP4) belongs to the transforming growth factor β (TGF-β) family of proteins. BMPs regulate cell proliferation, differentiation and motility, and have also been reported to be involved in cancer pathogenesis. We have previously shown that BMP4 reduces breast cancer cell proliferation through G1 cell cycle arrest and simultaneously induces migration in a subset of these cell lines. Here we examined the effects of BMP4 in a more physiological environment, in a 3D culture system.

Methods

We used two different 3D culture systems; Matrigel, a basement membrane extract from mouse sarcoma cells, and a synthetic polyethylene glycol (PEG) gel. AlamarBlue reagent was used for cell proliferation measurements and immunofluorescence was used to determine cell polarity. Expression of cell cycle regulators was examined by Western blot and matrix metalloproteinase (MMP) expression by qRT-PCR.

Results

The MCF-10A normal breast epithelial cells formed round acini with correct apicobasal localization of α6 integrin in Matrigel whereas irregular structures were seen in PEG gel. The two 3D matrices also supported dissimilar morphology for the breast cancer cells. In PEG gel, BMP4 inhibited the growth of MCF-10A and the three breast cancer cell lines examined, thus closely resembling the 2D culture conditions, but in Matrigel, no growth inhibition was observed in MDA-MB-231 and MDA-MB-361 cells. Furthermore, BMP4 induced the expression of the cell cycle inhibitor p21 both in 2D and 3D culture, thereby partly explaining the growth arrest. Interestingly, MDA-MB-231 cells formed large branching, stellate structures in response to BMP4 treatment in Matrigel, suggestive of increased cell migration or invasion. This effect was reversed by Batimastat, a broad-spectrum MMP inhibitor, and subsequent analyses showed BMP4 to induce the expression of MMP3 and MMP14, that are thus likely to be responsible for the stellate phenotype.

Conclusions

Taken together, our results show that Matrigel provides a more physiological environment for breast epithelial cells than PEG gel. Moreover, BMP4 partly recapitulates in 3D culture the growth suppressive abilities previously seen in 2D culture and induces an MMP-dependent migratory phenotype in MDA-MB-231 cells.

Bone morphogenetic protein 4 expression in multiple normal and tumor tissues reveals its importance beyond development

Bone morphogenetic proteins (BMPs) are extracellular signaling molecules that belong to the transforming growth factor β (TGFβ) superfamily and are known to regulate cell proliferation, differentiation and motility, especially during development. BMP4 has an indispensable role in vertebrate development while limited information on BMP4 expression and function exists in adult tissues. Nevertheless, its contribution to cancer development and progression has gained increasing interest in recent years. Functional studies, especially in breast cancer, have implicated BMP4 both in inhibition of cell proliferation and in promotion of cell migration and invasion. To gain an insight into the function of BMP4 in normal and cancer tissues, BMP4 protein expression levels were analyzed by immunohistochemistry in 34 different normal organs/tissues, 34 different tumor types and finally in 486 breast cancer samples where possible associations between BMP4 and clinicopathological parameters were statistically evaluated. In over 20% of normal and malignant tissues, BMP4 was expressed at high level. Strong expression was observed particularly in some normal epithelial cells, such as bladder and stomach, and in squamous cell carcinomas. In breast cancer, strong BMP4 expression was detected in 25% of patients, and was associated with low proliferation index and increased frequency of tumor recurrence. Taken together, BMP4 is expressed in a subset of normal adult tissues and is likely to contribute to tissue homeostasis. However, in tumors, BMP4 expression levels vary considerably, implying diverse roles in different tumor types. This role is biphasic in breast cancer as BMP4 expression is linked to reduced proliferation and increased recurrence, thus corroborating our previous in-vitro functional data.

BMP-binding protein twisted gastrulation is required in mammary gland epithelium for normal ductal elongation and myoepithelial compartmentalization

Bone morphogenetic proteins (BMPs) are involved in embryonic mammary gland (MG) development and can be dysregulated in breast cancer. However, the role BMPs play in the postnatal MG remains virtually unknown. BMPs are potent morphogens that are involved in cell fate determination, proliferation, apoptosis and adult tissue homeostasis. Twisted gastrulation (TWSG1) is a secreted BMP binding protein that modulates BMP ligand availability in the extracellular space. Here we investigate the consequences of TWSG1 deletion on development of the postnatal MG. At puberty, Twsg1 is expressed in the myoepithelium and in a subset of body cells of the terminal end buds. In the mature duct, Twsg1 expression is primarily restricted to the myoepithelial layer. Global deletion of Twsg1 leads to a delay in ductal elongation, reduced secondary branching, enlarged terminal end buds, and occluded lumens. This is associated with an increase in luminal epithelial cell number and a decrease in apoptosis. In the MG, pSMAD1/5/8 level and the expression of BMP target genes are reduced, consistent with a decrease in BMP signaling. GATA-3, which is required for luminal identity, is reduced in Twsg1(-/-) MGs, which may explain why K14 positive cells, which are normally restricted to the myoepithelial layer, are found within the luminal compartment and shed into the lumen. In summary, regulation of BMP signaling by TWSG1 is required for normal ductal elongation, branching of the ductal tree, lumen formation, and myoepithelial compartmentalization in the postnatal MG.

Bone morphogenetic protein 4-a fascinating regulator of cancer cell behavior

Bone morphogenetic proteins (BMPs) are extracellular signaling molecules that belong to the transforming growth factor β (TGFβ) superfamily and are well-known for their indispensable roles in vertebrate development. In recent years, important new information has been generated on the contribution of BMP family members, such as BMP4, in cancer pathogenesis. First of all, BMP4 gene variants have been shown to predispose to colorectal cancer. In sporadic cancer, BMP4 expression levels are commonly altered in many tumor types and have been linked to patient prognosis in hepatocellular and ovarian cancer. In terms of BMP4 function in cancer cells, the majority of studies demonstrate that BMP4 suppresses cell growth both in vitro and in vivo, and at the same time is able to induce migration, invasion, and epithelial-mesenchymal transition. These latter phenotypes are typically associated with cancer metastasis and progression, and thus BMP4 seems to elicit effects that are both detrimental and beneficial for the cancer cells. The functional effects of BMP4 are not restricted to the control of cell proliferation and mobility, since it also contributes to the regulation of differentiation, apoptosis, and angiogenesis. The latter is especially intriguing since the formation of new blood vessels is a prerequisite for sustained tumor growth and cancer progression. Mainly due to its growth suppressive abilities, BMP4 has been suggested as a possible therapeutic target in cancer cells. However, the other functional characteristics of BMP4, especially the promotion of cell mobility, make such strategies less appealing. Improved knowledge of the downstream mediators of BMP4 effects in cancer cells may allow dissection of the different BMP4-induced phenotypes and thereby generation of specific targeted therapies.

The bone morphogenetic protein receptor-1A pathway is required for lactogenic differentiation of mammary epithelial cells in vitro

Bone morphogenetic proteins (BMPs) have been implicated in the control of proliferation, tissue formation, and differentiation. BMPs regulate the biology of stem and progenitor cells and can promote cellular differentiation, depending on the cell type and context. Although the BMP pathway is known to be involved in early embryonic development of the mammary gland via mesenchymal cells, its role in later epithelial cellular differentiation has not been examined. The majority of the mammary gland development occurs post-natal, and its final functional differentiation is characterized by the emergence of alveolar cells that produce milk proteins. Here, we tested the hypothesis that bone morphogenetic protein receptor 1A (BMPR1A) function was required for mammary epithelial cell differentiation. We found that the BMPR1A-SMAD1/5/8 pathway was predominantly active in undifferentiated mammary epithelial cells, compared with differentiated cells. Reduction of BMPR1A mRNA and protein, using short hairpin RNA, resulted in a reduction of SMAD1/5/8 phosphorylation in undifferentiated cells, indicating an impact on this pathway. When the expression of the BMPR1A gene knocked down in undifferentiated cells, this also prevented beta-casein production during differentiation of the mammary epithelial cells by lactogenic hormone stimulation. Addition of Noggin, a BMP antagonist, also prevented beta-casein expression. Together, this demonstrated that BMP-BMPR1A-SMAD1/5/8 signal transduction is required for beta-casein production, a marker of alveolar cell differentiation. This evidence functionally identifies BMPR1A as a potential new regulator of mammary epithelial alveolar cell differentiation.

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.

Analysis of BMP4 and BMP7 signaling in breast cancer cells unveils time-dependent transcription patterns and highlights a common synexpression group of genes

Background

Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily of growth factors. They are known for their roles in regulation of osteogenesis and developmental processes and, in recent years, evidence has accumulated of their crucial functions in tumor biology. BMP4 and BMP7, in particular, have been implicated in breast cancer. However, little is known about BMP target genes in the context of tumor. We explored the effects of BMP4 and BMP7 treatment on global gene transcription in seven breast cancer cell lines during a 6-point time series, using a whole-genome oligo microarray. Data analysis included hierarchical clustering of differentially expressed genes, gene ontology enrichment analyses and model based clustering of temporal data.

Results

Both ligands had a strong effect on gene expression, although the response to BMP4 treatment was more pronounced. The cellular functions most strongly affected by BMP signaling were regulation of transcription and development. The observed transcriptional response, as well as its functional outcome, followed a temporal sequence, with regulation of gene expression and signal transduction leading to changes in metabolism and cell proliferation. Hierarchical clustering revealed distinct differences in the response of individual cell lines to BMPs, but also highlighted a synexpression group of genes for both ligands. Interestingly, the majority of the genes within these synexpression groups were shared by the two ligands, probably representing the core molecular responses common to BMP4 and BMP7 signaling pathways.

Conclusions

All in all, we show that BMP signaling has a remarkable effect on gene transcription in breast cancer cells and that the functions affected follow a logical temporal pattern. Our results also uncover components of the common cellular transcriptional response to BMP4 and BMP7. Most importantly, this study provides a list of potential novel BMP target genes relevant in breast cancer.

Epithelial Bmp (Bone morphogenetic protein) signaling for bulbourethral gland development: a mouse model for congenital cystic dilation

The bulbourethral gland (BUG) is a male-specific organ, which secretes part of the semen fluid. As the BUG is located in the deep pelvic floor, its developmental process is still unclear. Bone morphogenetic protein (Bmp) signaling plays pivotal roles in various organs. However, the function of Bmp signaling for BUG development is still unclear. The present study aimed to elucidate the role of Bmp signaling in the development of the BUG. We observed the prominent nuclear accumulation of phosphorylated (p) SMAD1/5/8, the downstream molecules of Bmp signaling, during BUG epithelial development. These results suggest that Bmp signaling contributes to BUG development. Bmp receptor1a (Bmpr1a) is known as the major type 1 signal transducer in some organogeneses. To analyze the Bmp signaling function for BUG development, we examined epithelial cell-specific Bmpr1a gene conditional mutant mice utilizing the tamoxifen-inducible Cre recombinase system. We observed cystic dilation and epithelial hyperplasia of the BUG in the Bmpr1a conditional knockout mice. The mutant cystic BUG specimens also showed inflammatory lesions. These BUG abnormalities resembled some of the BUG malformations observed in human congenital syndromes. The current study suggests that Bmp signaling possesses an essential role in BUG development and homeostasis. This would be the first report showing that the mutation of the Bmpr1a gene in the BUG epithelia phenocopied some abnormalities of human congenital syndromes affecting the BUG duct.

Disruption of bone morphogenetic protein receptor 2 (BMPR2) in mammary tumors promotes metastases through cell autonomous and paracrine mediators

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily of signaling molecules. BMPs can elicit a wide range of effects in many cell types and have previously been shown to induce growth inhibition in carcinoma cells as well as normal epithelia. Recently, it has been demonstrated that BMP4 and BMP7 are overexpressed in human breast cancers and may have tumor suppressive and promoting effects. We sought to determine whether disruption of the BMP receptor 2 (BMPR2) would alter mammary tumor progression in mice that express the Polyoma middle T antigen. Mice expressing Polyoma middle T antigen under the mouse mammary tumor virus promoter were combined with mice that have doxycycline-inducible expression of a dominant-negative (DN) BMPR2. We did not observe any differences in tumor latency. However, mice expressing the BMPR2-DN had a fivefold increase in lung metastases. We characterized several cell autonomous changes and found that BMPR2-DN-expressing tumor cells had higher rates of proliferation. We also identified unique changes in inflammatory cells and secreted chemokines/cytokines that accompanied BMPR2-DN-expressing tumors. By immunohistochemistry, it was found that BMPR2-DN primary tumors and metastases had an altered reactive stroma, indicating specific changes in the tumor microenvironment. Among the changes we discovered were increased myeloid derived suppressor cells and the chemokine CCL9. BMP was shown to directly regulate CCL9 expression. We conclude that BMPR2 has tumor-suppressive function in mammary epithelia and microenvironment and that disruption can accelerate mammary carcinoma metastases.

Effects of siRNA-targeting BMP-2 on the abilities of migration and invasion of human liver cancer SMMC7721 cells and its mechanism

To observe the effects of small interfering RNA (siRNA)-targeting bone morphogenetic protein (BMP)-2 on the abilities of migration and invasion of human liver cancer SMMC7721 cells and its mechanism. Three siRNAs-targeting BMP-2 gene were synthesized. There were six groups including group I (non-transfected cells), group II (only liposome-transfected cells), group III (non-specific siRNA-transfected cells) and groups IV-VI (siRNA-A, siRNA-B and siRNA-C-targeting BMP-2 transfected cells, respectively). SMMC7721 cells were instantaneously transfected using lipofectamine method. The levels of mRNA and protein of BMP-2 in cells were determined with reverse transcription-PCR and western blotting. The abilities of migration and invasion of transfected cells were assessed using scratch test and in vitro invasion assay, respectively. The protein levels of p-ERK, p-JNK and p-p38 and the protein levels of MMP-2 and MMP-9 were evaluated with western blot 48 h after siRNA-B-targeting BMP-2 was transfected into liver cancer SMMC7721 cells. Expression of mRNA and protein of BMP-2 in groups IV-VI were significantly inhibited, especially in group V. Cell scratch width was significantly greater in group V than in group I and III (P<0.01). In vitro invasion assay suggested that the number of invasion of cells was significantly lower in group V than in group I and III (P<0.05). Western blot indicated that the level of p-ERK was significantly decreased (P<0.05), the levels of p-JHK and p-p38 were not significantly changed and the levels of MMP-2 and MMP-9 were significantly downregulated (P<0.05). siRNA-targeting BMP-2 can markedly inhibited the expression of BMP-2 in liver cancer SMMC7721 cells, and decrease the abilities of migration and invasion of liver cancer cells, especially siRNA-B. The inhibitory effects of siRNA-B-targeting BMP-2 on the abilities of migration and invasion of human liver cancer SMMC7721 cells may be caused by the downregulation of MMP-2 and MMP-9 through MAPK/ERK pathway, whereas is not related to MAPK/JNK and MAPK/p38 pathway.

The Yin and Yang of bone morphogenetic proteins in cancer

Bone morphogenetic proteins (BMPs) were first studied as growth factors or morphogens of the transforming growth factor-beta superfamily. These growth molecules, originally associated with bone and cartilage development, are now known to play an important role in morphogenesis and homeostasis in many other tissues. More recently, significant contributions from BMPs, their receptors, and interacting molecules have been linked to carcinogenesis and tumor progression. On the other hand, BMPs can sometimes function as a tumor suppressor. Our report highlights these new roles in the pathogenesis of cancer that may suggest novel targets for therapeutic intervention.

Is there a role for mammary stem cells in inflammatory breast carcinoma?: a review of evidence from cell line, animal model, and human tissue sample experiments

Stem cells are pluripotent cells, with a large replicative potential, which perform normal physiological functions such as tissue renewal and damage repair. However, because of their long lifespan and high replicative potential, stem cells are ideal targets to accumulate multiple mutations. Therefore, they can be regarded as being responsible for the initiation of tumor formation. In the past, numerous studies have shown that the presence of an elaborate stem cell compartment within a tumor is associated with aggressive tumor cell behavior, frequent formation of metastases, resistance to therapy, and poor patient survival. From this perspective, tumors from patients with inflammatory breast cancer (IBC), an aggressive breast cancer subtype with a dismal clinical course, are most likely to be associated with stem cell biology. To date, this hypothesis is corroborated by evidence resulting from in vitro and in vivo experiments. Both gene and microRNA expression profiles highlighted several stem cell-specific signal transduction pathways that are hyperactivated in IBC. Also, these stem cell-specific signal transduction pathways seem to converge in the activation of nuclear factor-kappa B, a molecular hallmark of IBC, and induction of epithelial-to-mesenchymal transition. Recently, the latter mechanism was identified as a prerequisite for the induction of stem cell characteristics in breast cancer cells.

Wnt3a-induced mesoderm formation and cardiomyogenesis in human embryonic stem cells

In vitro differentiation of human embryonic stem cells (hESCs) into pure human cardiomyocytes (hESCMs) would present a powerful tool to further the creation of cell models designed to advance preclinical drug development. Here, we report a novel differentiation method to substantially increase hESCM yield. Upon early and transient treatment of hESCs with Wnt3a, embryoid body and mesendoderm formation is enhanced, leading to greater differentiation toward cardiomyocytes. Moreover, the generated beating clusters are highly enriched with cardiomyocytes (50%) and express genes characteristic of cardiac cells, providing evidence that these hESCMs are competent to develop in vitro into functional and physiologically relevant cardiomyocytes. In summary, this protocol not only has the potential to guarantee a renewable supply of enriched cardiomyocyte populations for developing novel and more predictive cell models, but it also should provide valuable insights into pathways critical for cardiac regeneration.

Bone morphogenetic protein-2 levels are elevated in the patients with gastric cancer and correlate with disease progression

Bone morphogenetic protein-2 (BMP-2) was reported to enhance migration, invasion, and metastasis at the various types of cancer cells. The purpose of this study is to identify the role of BMP-2 in progression of gastric cancer. Forty-four patients with operable gastric cancer were enrolled. Also, twenty healthy volunteers were enrolled as control group. All patients received gastrectomy with D2 lymphadenectomy, and surgical staging was performed. Whole blood was obtained preoperatively in all patients, and serum BMP-2 levels were quantified by commercially available ELISA kit. Immunohistochemical stain for BMP-2 in all gastric cancer tissues was performed using tissue microarray. All patients showed increased serum BMP-2 levels compared with control group, when upper normal limit was defined as the mean of control serum level+2×standard deviation. The mean serum BMP-2 level of lymph node positive group was significantly elevated than that of lymph node-negative group (382.7 pg/ml, 95% CI 341.99-423.4 pg/ml vs 211.69 pg/ml, 95% CI 191.09-232.29 pg/ml, P<0.001). The serum BMP-2 was strongly correlated with the depth of invasion (T stage) and the extent of regional lymph node involvement (N stage) (r=0.662, P<0.001 and r=0.831, P<0.001, respectively). Moreover, the serum BMP-2 was correlated with the grade of tumor histology(r=0.421, P=0.008). Immunohistochemical stain showed the specific expression of BMP-2 in cancer cells compared with normal gastric mucosa. In conclusion, serum BMP-2 is associated with progression from early localized gastric cancer to locally advanced gastric cancer.

The Bone Morphogenesis Protein-2 (BMP-2) is associated with progression to metastatic disease in gastric cancer

PURPOSE

Bone Morphogenetic Proteins (BMPs) are members of the TGF-beta superfamily and it has been demonstrated that BMPs enhance migration, invasion and metastasis. The purpose of this study was to identify the association between the serum BMP-2 level and the progression status of gastric cancer.

MATERIALS AND METHODS

Fifty-five patients with metastatic gastric cancer (metastatic disease group), six patients with early gastric cancer without lymph node metastasis (the EGC group), and ten healthy control subjects were enrolled in this study. The serum BMP-2 level was quantified by use of a commercially available ELISA kit. In EGC group patients and patients with metastatic disease, whole blood was obtained before endoscopic mucosal resection and before the commencement of a scheduled cycle of systemic chemotherapy, respectively.

RESULTS

No significant difference in the mean serum BMP-2 levels was observed between the control subjects and the EGC group patients (87.95 pg/ml for the control subjects and 84.50 pg/ml for the EGC group, p=1.0). However, the metastatic disease group patients had a significantly higher level of serum BMP (179.61 pg/ml) than the control subjects and EGC group patients (87.95 pg/ml for the control subjects and 84.50 pg/ml for the EGC group, p<0.0001). Moreover, the mean serum BMP-2 level from patients with a bone metastasis was significantly higher than the mean serum BMP-2 level from patients without a bone metastasis (204.73 pg/ml versus 173.33 pg/ml, p=0.021).

CONCLUSIONS

BMP-2 seems to have a role in progression to metastatic disease in gastric cancer, especially in the late stage of tumorigenesis, including invasion and metastasis. BMP-2 may facilitate bone metastasis in gastric cancer. To confirm these findings, further studies are required with tissue specimens and the use of a cancer cell line.

Role of transforming growth factor-beta superfamily signaling pathways in human disease

Transforming growth factor beta (TGF-beta) superfamily signaling pathways are ubiquitous and essential regulators of cellular processes including proliferation, differentiation, migration, and survival, as well as physiological processes, including embryonic development, angiogenesis, and wound healing. Alterations in these pathways, including either germ-line or somatic mutations or alterations in the expression of members of these signaling pathways often result in human disease. Appropriate regulation of these pathways is required at all levels, particularly at the ligand level, with either a deficiency or an excess of specific TGF-beta superfamily ligands resulting in human disease. TGF-beta superfamily ligands and members of these TGF-beta superfamily signaling pathways also have emerging roles as diagnostic, prognostic or predictive markers for human disease. Ongoing studies will enable targeting of TGF-beta superfamily signaling pathways for the chemoprevention and treatment of human disease.

BMP4 induces an epithelial-mesenchymal transition-like response in adult airway epithelial cells

Bone morphogenetic proteins (BMPs) are critical morphogens and play key roles in epithelial-mesenchymal transitions (EMTs) during embryogenesis. BMP4 is required for early mesoderm formation and also regulates morphogenesis and epithelial cell differentiation in developing lungs. While, BMP signalling pathways are activated during lung inflammation in adult mice, the role of BMPs in adult lungs remains unclear. We hypothesised that BMPs are involved in remodelling processes in adult lungs and investigated effects of BMP4 on airway epithelial cells. BEAS-2B cell growth decreased in the presence of BMP4. Cells acquired a mesenchymal-like morphology with downregulation of adherens junction proteins and increased cell motility. Changes in extracellular matrix-related gene expression occurred with BMP4 treatment including upregulation of collagens, fibronectin and tenascin C. We conclude that the activity of BMP4 in EMT during development is recapitulated in adult airway epithelial cells and suggest that this activity may contribute to inflammation and fibrosis in vivo.

Bone morphogenetic protein 4 induces epithelial-mesenchymal transition through MSX2 induction on pancreatic cancer cell line

In our study, we found that bone morphogenetic protein 4 (BMP4) has a novel effect as an inducer of epithelial-mesenchymal transition (EMT) on Panc-1 cells, a human pancreatic carcinoma cell line. BMP4-treated Panc-1 cells showed loose cell contacts and a scattered, fibroblast-like appearance along with E-cadherin downregulation, Vimentin upregulation and enhanced cell migration, which are characteristic of EMT. BMP4 treatment also induced homeobox gene MSX2 expression, which we previously showed to be associated with EMT in pancreatic carcinoma cells. BMP4 treatment activated the Smad signaling pathway, and extracellular signal-related kinase (ERK) and p38 mitogen-activated kinase (MAPK) pathways in these cells. MSX2 was markedly induced by BMP4 through the ERK and p38 MAPK pathways in collaboration with the Smad signaling pathway. The repression of E-cadherin, induction of Vimentin and enhanced cell migration disappeared when siRNA-based MSX2 downregulated pancreatic cancer cells were treated with BMP4. These findings indicate that BMP4 may be involved in pancreatic carcinoma development through the promotion of EMT and that MSX2 is indispensable to this process.

BMP-6 promotes E-cadherin expression through repressing deltaEF1 in breast cancer cells

BACKGROUND

Bone morphogenetic protein-6 (BMP-6) is critically involved in many developmental processes. Recent studies indicate that BMP-6 is closely related to tumor differentiation and metastasis.

METHODS

Quantitative RT-PCR was used to determine the expression of BMP-6, E-cadherin, and deltaEF1 at the mRNA level in MCF-7 and MDA-MB-231 breast cancer cells, as well as in 16 breast cancer specimens. Immunoblot analysis was used to measure the expression of deltaEF1 at the protein level in deltaEF1-overexpressing and deltaEF1-interfered MDA-MB-231 cells. Luciferase assay was used to determine the rhBMP-6 or deltaEF1 driven transcriptional activity of the E-cadherin promoter in MDA-MB-231 cells. Quantitative CHIP assay was used to detect the direct association of deltaEF1 with the E-cadherin proximal promoter in MDA-MB-231 cells.

RESULTS

MCF-7 breast cancer cells, an ER+ cell line that expressed high levels of BMP-6 and E-cadherin exhibited very low levels of deltaEF1 transcript. In contrast, MDA-MB-231 cells, an ER- cell line had significantly reduced BMP-6 and E-cadherin mRNA levels, suggesting an inverse correlation between BMP-6/E-cadherin and deltaEF1. To determine if the same relationship exists in human tumors, we examined tissue samples of breast cancer from human subjects. In 16 breast cancer specimens, the inverse correlation between BMP-6/E-cadherin and deltaEF1 was observed in both ER+ cases (4 of 8 cases) and ER- cases (7 of 8 cases). Further, we found that BMP-6 inhibited deltaEF1 transcription, resulting in an up-regulation of E-cadherin mRNA expression. This is consistent with our analysis of the E-cadherin promoter demonstrating that BMP-6 was a potent transcriptional activator. Interestingly, ectopic expression of deltaEF1 was able to block BMP-6-induced transactivation of E-cadherin, whereas RNA interference-mediated down-regulation of endogenous deltaEF1 in breast cancer cells abolished E-cadherin transactivation by BMP-6. In addition to down-regulating the expression of deltaEF1, BMP-6 also physically dislodged deltaEF1 from E-cadherin promoter to allow the activation of E-cadherin transcription.

CONCLUSION

We conclude that repression of deltaEF1 plays a key role in mediating BMP-6-induced transcriptional activation of E-cadherin in breast cancer cells. Consistent with the fact that higher level of deltaEF1 expression is associated with more invasive phenotype of breast cancer cells, our collective data suggests that deltaEF1 is likely the switch through which BMP-6 restores E-cadherin-mediated cell-to-cell adhesion and prevents breast cancer metastasis.

Bone morphogenetic protein

Bone morphogenetic proteins (BMPs) are multi-functional growth factors belonging to the transforming growth factor-beta superfamily. It has been demonstrated that BMPs had been involved in the regulation of cell proliferation, survival, differentiation and apoptosis. However, their hallmark ability is that play a pivotal role in inducing bone, cartilage, ligament, and tendon formation at both heterotopic and orthotopic sites. In this review, we mainly concentrate on BMP structure, function, molecular signaling and potential medical application.