Bone morphogenetic protein-9 induces apoptosis in prostate cancer cells, the role of prostate apoptosis response-4

Bone morphogenetic protein (BMP)9 in cancer development: mechanistic, diagnostic, and therapeutic approaches?

Bone morphogenetic protein (BMP)-9 is considered a member of the transforming growth factor (TGF)β superfamily. It was first found as an inducer of bone and cartilage formation and then discovered that this factor mediates several physiologic functions and hemostasis. Besides physiological conditions, BMP9 has also been elucidated that it is involved in several pathological situations, especially cancer. In various cancers, dysregulation of BMP9 has raised the issue that BMP9 might play a conflicting role in tumour development. BMP9 binding to its receptors (BMPRs), including ALKs and BMPRII, induces canonical SMAD-dependent and non-canonical PI3K/AKT and MAPK signalling pathways in tumour cells. BMP9, via inducing apoptosis, inhibiting tumour-promoting cell signalling pathways, suppressing epithelial-mesenchymal transition (EMT) process, blocking angiogenesis, and preventing cross-talk in the tumour microenvironment, mainly exerts tumour-suppressive functions. In contrast, BMP9 triggers tumour-supportive signalling pathways, promotes EMT, and enhances angiogenesis, suggesting that BMP9 is also involved in tumour development. It has been demonstrated that modulating BMP9 expression and functions might be a promising approach to cancer treatment. It has also been indicated that evaluating BMP9 expression in cancers might be a biomarker for predicting cancer prognosis. Overall, BMP9 would provide a promising target in cancer management.

Reciprocal SOX2 regulation by SMAD1-SMAD3 is critical for anoikis resistance and metastasis in cancer

Growth factors in tumor environments are regulators of cell survival and metastasis. Here, we reveal the dichotomy between TGF-β superfamily growth factors BMP and TGF-β/activin and their downstream SMAD effectors. Gene expression profiling uncovers SOX2 as a key contextual signaling node regulated in an opposing manner by BMP2, -4, and -9 and TGF-β and activin A to impact anchorage-independent cell survival. We find that SOX2 is repressed by BMPs, leading to a reduction in intraperitoneal tumor burden and improved survival of tumor-bearing mice. Repression of SOX2 is driven by SMAD1-dependent histone H3K27me3 recruitment and DNA methylation at SOX2's promoter. Conversely, TGF-β, which is elevated in patient ascites, and activin A can promote SOX2 expression and anchorage-independent survival by SMAD3-dependent histone H3K4me3 recruitment. Our findings identify SOX2 as a contextual and contrastingly regulated node downstream of TGF-β members controlling anchorage-independent survival and metastasis in ovarian cancers.

Differential bioactivity of four BMP-family members as function of biomaterial stiffness

While a soft film itself is not able to induce cell spreading, BMP-2 presented via such soft film (so called "matrix-bound BMP-2") was previously shown to trigger cell spreading, migration and downstream BMP-2 signaling. Here, we used thin films of controlled stiffness presenting matrix-bound BMPs to study the effect of four BMP members (BMP-2, 4, 7, 9) on cell adhesion and differentiation of skeletal progenitors. We performed automated high-content screening of cellular responses, including cell number, cell spreading area, SMAD phosphorylation and alkaline phosphatase activity. We revealed that the cell response to bBMPs is BMP-type specific, and involved certain BMP receptors and beta chain integrins. In addition, this response is stiffness-dependent for several receptors. The basolateral presentation of the BMPs allowed us to discriminate the specificity of cellular response, especiallyd the role of type I and II BMP receptors and of β integrins in a BMP-type and stiffness-dependent manner. Notably, BMP-2 and BMP-4 were found to have distinct roles, while ALK5, previously known as a TGF-β receptor was revealed to be involved in the BMP-pathway.

Novel Pathways for Targeting Tumor Angiogenesis in Metastatic Breast Cancer

Breast cancer is the most common cancer affecting women and is the second leading cause of cancer related death worldwide. Angiogenesis, the process of new blood vessel development from pre-existing vasculature, has been implicated in the growth, progression, and metastasis of cancer. Tumor angiogenesis has been explored as a key therapeutic target for decades, as the blockade of this process holds the potential to reduce the oxygen and nutrient supplies that are required for tumor growth. However, many existing anti-angiogenic approaches, such as those targeting Vascular Endothelial Growth Factor, Notch, and Angiopoietin signaling, have been associated with severe side-effects, limited survival advantage, and enhanced cancer regrowth rates. To address these setbacks, alternative pathways involved in the regulation of tumor angiogenesis are being explored, including those involving Bone Morphogenetic Protein-9 signaling, the Sonic Hedgehog pathway, Cyclooxygenase-2, p38-mitogen-activated protein kinase, and Chemokine Ligand 18. This review article will introduce the concept of tumor angiogenesis in the context of breast cancer, followed by an overview of current anti-angiogenic therapies, associated resistance mechanisms and novel therapeutic targets.

New insights into BMP9 signaling in liver diseases

Bone morphogenetic protein 9 (BMP9) is a recently discovered cytokine mainly secreted by the liver and is a member of the transforming growth factor β (TGF-β) superfamily. In recent years, an increasing number of studies have shown that BMP9 is associated with liver diseases, including nonalcoholic fatty liver disease (NAFLD), liver fibrosis and hepatocellular carcinoma (HCC), and BMP9 signaling may play dual roles in liver diseases. In this review, we mainly summarized and discussed the roles and potential mechanisms of BMP9 signaling in NAFLD, liver fibrosis and HCC. Specifically, this article will provide a better understanding of BMP9 signaling and new clues for the treatment of liver diseases.

GDF10 inhibits proliferation and epithelial-mesenchymal transition in triple-negative breast cancer via upregulation of Smad7

Triple-negative breast cancer (TNBC) cannot be treated with current hormonal therapies and has a higher risk of relapse than other breast cancers. To identify potential therapeutic targets for TNBC, we conducted microRNA sequencing (RNA-Seq) in human TNBC specimens and tumor-matched controls. We found that growth differentiation factor-10 (GDF10), a member of the TGF-β superfamily, was downregulated in tumor samples. Further analysis of GDF10 expression in a larger set of clinical TNBC samples using qPCR confirmed its downregulation and association with parameters of disease severity. Using human-derived TNBC cell lines, we carried out GDF10 under- and overexpression experiments, which showed that GDF10 loss promoted cell proliferation and invasion. By contrast, overexpression of GDF10 inhibited proliferation, invasion, and epithelial mesenchymal transition (EMT) via upregulation of Smad7 and E-Cadherin, downregulation of p-Smad2 and N-Cadherin, and reduction of nuclear Smad4 expression. In addition, overexpression of GDF10 reduced tumor burden and induced apoptosis in a TNBC xenograft mouse model. These findings indicate that GDF10 acts as a tumor suppressor in mammary epithelial cells that limits proliferation and suppresses EMT. Efforts aimed at restoring GDF10 expression may thus bring a long-sought therapeutic alternative in the treatment of patients with TNBC.

Bone morphogenetic protein-9 promotes the proliferation of non-small cell lung cancer cells by activating PI3K/Akt and Smad1/5 pathways

Non-small-cell lung carcinoma (NSCLC) is any type of epithelial lung cancer other than small cell lung carcinoma (SCLC), which accounts for about 85% of all lung cancers. Bone morphogenetic protein (BMP)-9 in humans is encoded by the growth differentiation factor 2 gene, which belongs to the transforming growth factor-beta superfamily. In the present study, we explored the role of BMP-9 in A549 and NCI-H1650 cell proliferation and its possible molecular mechanisms. 25 NSCLC patients were recruited to evaluate mRNA expression of BMP-9 to determine its clinicopathologic significance. We found that recombinant protein BMP-9 and overexpression of BMP-9 promoted A549 and NCI-H1650 cell proliferation in vitro, which was abolished by phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002). Western blot results revealed that BMP-9 significantly activated the PI3K/Akt and Smad1/5 pathway signaling. In vivo, BMP-9 promoted tumor growth and PI3K/Akt and Smad1/5 signaling pathways in an A549 or NCI-H1650 cell line-derived xenograft model. Knockdown BMP-9 or BMP-9 receptor ALK1 inhibited A549 cell growth in vitro and in vivo, which was associated with regulating the PI3K/Akt and Smad1/5 signaling pathways. These results demonstrated that BMP-9 promoted A549 and NCI-H1650 cell proliferation via PI3K/Akt and Smad1/5 signaling pathways.

BMP9 signaling promotes the normalization of tumor blood vessels

The presence of an immature tumor vascular network contributes to cancer dissemination and the development of resistance to therapies. Strategies to normalize the tumor vasculature are therefore of significant therapeutic interest for cancer treatments. VEGF inhibitors are used clinically to normalize tumor blood vessels. However, the time frame and dosage of these inhibitors required to achieve normalization is rather narrow, and there is a need to identify additional signaling targets to attain vascular normalization. In addition to VEGF, the endothelial-specific receptor Alk1 plays a critical role in vascular development and promotes vascular remodeling and maturation. Therefore, we sought to evaluate the effects of the Alk1 ligand BMP9 on tumor vascular formation. BMP9 overexpression in Lewis Lung Carcinoma (LLC) tumors significantly delayed tumor growth. Blood vessels in BMP9-overexpressing LLC tumors displayed markers of vascular maturation and were characterized by increased perivascular cell coverage. Tumor vasculature normalization was associated with decreased permeability and increased perfusion. These changes in vascular function in BMP9-overexpressing LLC tumors resulted in significant alterations of the tumor microenvironment, characterized by a decrease in hypoxia and an increase in immune infiltration. In conclusion, we show that BMP9 promotes vascular normalization in LLC tumors that leads to changes in the microenvironment.

BMP-9 is a novel marker for colorectal tumorigenesis undergoing the normal mucosa-adenoma-adenocarcinoma sequence and is associated with colorectal cancer prognosis

Depending on the type of cancer, bone morphogenetic protein-9 (BMP-9) can promote or inhibit tumorigenesis; however, the function of BMP-9 in colorectal cancer remains unclear. The aim of the present study was to evaluate the clinicopathological importance of BMP-9 expression in the tumorigenesis of normal colorectal epithelial tissue, and subsequent transformation into adenoma and carcinoma. In addition, the present study aimed to determine the prognostic value of BMP-9 on the survival of patients with colorectal cancer (CRC). A total of 65 patients with pathologically confirmed colorectal adenocarcinoma and a history of adenoma were enrolled. BMP-9 and Ki-67 expression was assessed retrospectively using paraffin-embedded samples of normal colorectal mucosa, colorectal adenoma and CRC obtained from each patient. The prognostic value of BMP-9 expression was analyzed in a group comprising 48 patients with CRC and a mean follow-up duration of 39.1 months. Bioinformatics analyses were performed in order to validate the results of the present study using published CRC datasets. The results from the present study suggested that the expression of BMP-9 gradually increased during the transition from normal mucosa to adenoma and subsequent adenocarcinoma (P<0.05); however, no significant association between the expression levels of BMP-9 and the clinicopathological parameters of patients was reported. Kaplan-Meier analysis revealed that patients with high expression levels of BMP-9 exhibited shorter overall survival rate than those with low levels of expression (54.7 vs. 41.3 months; log-rank test, P<0.05). Furthermore, regardless of tumor location and the presence of blood vessel tumor emboli, the univariate and multivariate analyses indicated that BMP-9 expression may be an independent prognostic factor for the overall survival rate of patients with CRC. The results of the present study suggested that BMP-9 may serve an oncogenic role and possess prognostic value in CRC.

CD105 overexpression mediates drug-resistance in choriocarcinoma cells through BMP9/Smad pathway

Background: CD105 (endoglin, ENG) is a membranous protein that is overexpressed in tumor-associated endothelial cells and some actual tumor cells and is associated with poor prognosis. However, the association between CD105 and response to chemoresistance in choriocarcinoma cells has not been clearly defined. The present study aimed to investigate the effects of targeting CD105 in drug-resistant choriocarcinoma.

Methods: CD105 expression was evaluated in drug-resistant and parental choriocarcinoma cells by qRT-PCR, western blotting, and immunofluorescence. CD105 overexpressing and knockdown cells were established by lentiviral transfection. CCK8, transwell, and flow cytometric assays were used to measure changes in drug-sensitivity, invasion, migration, and apoptosis. Drug-sensitivity and Smad1/5/8, Smad2, and Smad3 expression were also detected after BMP9 treatment. Immunohistochemical staining for CD105 and BMP9 was performed on choriocarcinoma tissues and the relationships between clinical and pathological characteristics were analysed.

Results: Data demonstrated that CD105 overexpression could decrease drug sensitivity, promote invasion and migration, and inhibit apoptosis in choriocarcinoma cells, and this protein was confirmed to mediate drug resistance through the BMP9/Smad pathway. Further experiments showed that the expression of CD105 and BMP9 was consistent in choriocarcinoma tissues and significantly associated with disease recurrence.

Conclusions: This study provides evidence suggesting that CD105 is critical for the development of drug-resistance in choriocarcinoma and might serve as a therapeutic target for reversing chemoresistance in choriocarcinoma patients.

The Interactivity between TGFβ and BMP Signaling in Organogenesis, Fibrosis, and Cancer

The Transforming Growth Factor beta (TGFβ) and Bone Morphogenic Protein (BMP) pathways intersect at multiple signaling hubs and cooperatively or counteractively participate to bring about cellular processes which are critical not only for tissue morphogenesis and organogenesis during development, but also for adult tissue homeostasis. The proper functioning of the TGFβ/BMP pathway depends on its communication with other signaling pathways and any deregulation leads to developmental defects or diseases, including fibrosis and cancer. In this review we explore the cellular and physio-pathological contexts in which the synergism or antagonism between the TGFβ and BMP pathways are crucial determinants for the normal developmental processes, as well as the progression of fibrosis and malignancies.

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.

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Describe the basics of TGF-β and BMP signalling

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

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

BMP signaling and its paradoxical effects in tumorigenesis and dissemination

Bone morphogenetic proteins (BMPs) play important roles in embryonic and postnatal development by regulating cell differentiation, proliferation, motility, and survival, thus maintaining homeostasis during organ and tissue development. BMPs can lead to tumorigenesis and regulate cancer progression in different stages. Therefore, we summarized studies on BMP expression, the clinical significance of BMP dysfunction in various cancer types, and the molecular regulation of various BMP-related signaling pathways. We emphasized on the paradoxical effects of BMPs on various aspects of carcinogenesis, including epithelial–mesenchymal transition (EMT), cancer stem cells (CSCs), and angiogenesis. We also reviewed the molecular mechanisms by which BMPs regulate tumor generation and progression as well as potential therapeutic targets against BMPs that might be valuable in preventing tumor growth and invasion.

Bone morphogenetic protein-9 is a potent growth inhibitor of hepatocellular carcinoma and reduces the liver cancer stem cells population

The biological role of BMP-9 signaling in liver cancer remains dubious. To explore the potential use of BMP-9 signaling for anti-cancer therapy, we used recombinant human BMP-9, which we referred to as MB109, to study the effect on growth of fifteen hepatocellular carcinoma (HCC) cell lines. MB109 effectively inhibits the proliferation of nine HCC cells in vitro. The anti-proliferative effect was found to be induced by turning on p21 signaling, which caused survivin suppression and G0/G1 cell cycle arrest. ID3 was identified to be the mediator of the MB109-induced p21 expression. Blocking the activity of p38 MAPK diminished ID3 and p21 expression, indicating that MB109 signals through a p38 MAPK/ID3/p21 pathway to arrest cell cycle progression. Moreover, prolonged MB109 treatment suppressed the expression of five prominent liver cancer stem cell (LCSC) markers, including CD44, CD90, AFP, GPC3 and ANPEP. Xenograft model confirmed the anti-tumor and LCSC-suppression capability of MB109 in vivo. Contrary to ongoing efforts of suppressing BMP-9 signaling to inhibit angiogenesis of cancer tissue, these results demonstrate an unexpected therapeutic potential of MB109 to stimulate BMP-9 signaling for anti-cancer therapies.

Reduced NOV expression correlates with disease progression in colorectal cancer and is associated with survival, invasion and chemoresistance of cancer cells

Aberrant expression of nephroblastoma overexpressed (NOV) has been evident in certain malignancies. In the current study, we aim to investigate the role played by NOV in colorectal cancer (CRC). NOV expression was determined in a cohort of 359 CRC tissues and 174 normal colorectal tissues. Its impact on CRC cells was investigated using in vitro NOV knockdown and overexpression models. NOV transcripts were reduced in the CRC tumours compared with the paired adjacent normal colorectal tissues (p < 0.01) and was associated with distant metastases. NOV knockdown resulted in increased cell proliferation and invasion of RKO cells, whilst an opposite effect was seen in the HT115 NOV over expressing cells. A positive association between Caspase-3/-8 and NOV was seen in NOV knockdown and overexpression cell lines which contributed to the survival of serum deprived CRC cells. Further investigation showed that NOV regulated proliferation, survival and invasion through the JNK pathway. NOV knockdown in RKO cells reduced the responsiveness to 5-Fluorouracil treatment, whilst overexpression in HT115 cells exhibited a contrasting effect. Taken together, NOV is reduced in CRC tumours and this is associated with disease progression. NOV inhibits the proliferation and invasion of CRC cells in vitro. Inhibition of proliferation is mediated by a regulation of Caspase-3/-8, via the JNK pathway, which has potential for predicting and preventing chemoresistance.

Impact of selective anti-BMP9 treatment on tumor cells and tumor angiogenesis

The role of bone morphogenic protein 9 (BMP9) signaling in angiogenesis has been controversial, with a number of studies showing that it acts either as a pro-angiogenic or, conversely, as an anti-angiogenic factor in a context-dependent manner. Notably, BMP9 was also reported to function in both pro- or anti-tumorigenic roles during tumor progression. It has therefore remained unclear, whether selective BMP9 inhibition is a useful target for antibody therapy of cancer. To shed light on these questions, we characterized BMP9 expression in plasma of patients with different cancer indications and found elevated levels of pro-domains and precursor BMP9 with a strong response in renal cell carcinoma (RCC). These studies prompted us to evaluate the potential of selective anti-BMP9 cancer therapy in RCC. We generated a novel monoclonal therapeutic antibody candidate, mAb BMP9-0093, that selectively targets all different BMP9 variants but does not bind to the closest homolog BMP10. In vitro, mAb BMP9-0093 treatment inhibited signaling, endothelin-1 (ET-1) production and spreading of endothelial cells and restored BMP9-induced decrease in pericyte migration and attachment. Furthermore, BMP9-mediated epithelial-mesenchymal transition of renal cell carcinoma cells was reversed by mAb BMP9-0093 treatment in vitro. In vivo, mAb BMP9-0093 showed significant anti-tumor activity that was associated with an increase in apoptosis as well as a decrease in tumor cell proliferation and ET-1 release. Furthermore, mAb BMP9-0093 induced mural cell coverage of endothelial cells, which was corroborated by a reduction in vascular permeability, demonstrated by a diminished penetration of omalizumab-Alexa 647 into tumor tissue. Our findings provide new evidence for a better understanding of BMP9 contribution in tumor progression and angiogenesis that may result in the development of effective targeted therapeutic interventions.

ALK1Fc Suppresses the Human Prostate Cancer Growth in in Vitro and in Vivo Preclinical Models

Prostate cancer is the second most common cancer in men and lethality is normally associated with the consequences of metastasis rather than the primary tumor. Therefore, targeting the molecular pathways that underlie dissemination of primary tumor cells and the formation of metastases has a great clinical value. Bone morphogenetic proteins (BMPs) play a critical role in tumor progression and this study focuses on the role of BMP9- Activin receptor-Like Kinase 1 and 2 (ALK1 and ALK2) axis in prostate cancer. In order to study the effect of BMP9 in vitro and in vivo on cancer cells and tumor growth, we used a soluble chimeric protein consisting of the ALK1 extracellular domain (ECD) fused to human Fc (ALK1Fc) that prevents binding of BMP9 to its cell surface receptors and thereby blocks its ability to activate downstream signaling. ALK1Fc sequesters BMP9 and the closely related BMP10 while preserving the activation of ALK1 and ALK2 through other ligands. We show that ALK1Fc acts in vitro to decrease BMP9-mediated signaling and proliferation of prostate cancer cells with tumor initiating and metastatic potential. In line with these observations, we demonstrate that ALK1Fc also reduces tumor cell proliferation and tumor growth in vivo in an orthotopic transplantation model, as well as in the human patient derived xenograft BM18. Furthermore, we also provide evidence for crosstalk between BMP9 and NOTCH and find that ALK1Fc inhibits NOTCH signaling in human prostate cancer cells and blocks the induction of the NOTCH target Aldehyde dehydrogenase member ALDH1A1, which is a clinically relevant marker associated with poor survival and advanced-stage prostate cancer. Our study provides the first demonstration that ALK1Fc inhibits prostate cancer progression, identifying BMP9 as a putative therapeutic target and ALK1Fc as a potential therapy. Altogether, these findings support the validity of ongoing clinical development of drugs blocking ALK1 and ALK2 receptor activity.

Overexpression of colorectal cancer oncogene CHRDL2 predicts a poor prognosis

Bone morphogenetic proteins (BMPs) both promote and suppress tumorigenesis, and multiple BMP antagonists reportedly contribute to cancer progression. In this study, we demonstrated that the BMP antagonist Chordin-like 2 (CHRDL2) is upregulated in colorectal cancer (CRC) tissues, and that CHRDL2 levels correlate with clinical features of CRC patients, including tumor size, TNM staging, and tumor differentiation. In addition, survival rate and Cox proportional hazards model analyses showed that high CHRDL2 levels correlate with a poor prognosis in CRC. Moreover, CHRDL2 promoted CRC cell proliferation in vitro and in vivo, perhaps through up-regulation of Cyclin D1 and down-regulation of P21. Co-immunoprecipitation assays showed that CHRDL2 bound to BMPs, which inhibited p-Smad1/5, thereby promoting CRC cell proliferation and inhibiting apoptosis. These results suggest CHRDL2 could serve as a biomarker of poor prognosis in CRC, and provide evidence that CHRDL2 acts as an oncogene in human CRC, making it a novel potential therapeutic target.

Low expression of BMPRIB indicates poor prognosis of breast cancer and is insensitive to taxane-anthracycline chemotherapy

Bone morphogenetic protein receptor type IB (BMPRIB) is one osteogenesis factor, which function in breast cancer has been rarely explored until recently. In the clinical study presented here, involving a cohort of 368 invasive ductal carcinoma (IDC) patients, we identified that patients with low expression of BMPRIB exhibited poor prognosis, especially in the luminal B subtype. We also provided the first piece of evidence that low level of BMPRIB was a promoting factor for breast cancer patients to develop bone metastasis, but not lung, liver or brain. The first of its kind, we reported that patients with high expression of BMPRIB exhibited favorable prognosis by a retrospective analysis consisting of 168 patients treated with TE (taxane and anthracycline) regimens. And the patients with high expression of BMPRIB were more sensitive to TE regimens in the detection of 32 paired pre-neoadjuvant and post-neoadjuvant specimens. Overall, our study concluded that low expression of BMPRIB indicated poor prognosis of breast cancer and was insensitive to taxane-anthracycline chemotherapy. Our findings also lay a foundation to help clinicians improve identification of patients for TE regimens by BMPRIB in the era of precision medicine.

BMP9 inhibits the growth and migration of lung adenocarcinoma A549 cells in a bone marrow stromal cell‑derived microenvironment through the MAPK/ERK and NF-κB pathways

Bone is the most common distant metastatic site of lung cancer, and is particularly prone to osteolytic damage. Soluble factors secreted from bone marrow-derived cells and tumor cells contribute to the growth and metastasis of cancer cells, and enhance osteolytic damage. BMP9, as the most powerful osteogenetic factor of the bone morphogenetic protein (BMP) family, can regulate the development of various tumors. However, the effects and underlying mechanisms of BMP9 in regards to lung cancer and the bone metastatic microenvironment are poorly understood. Here, we determined the inhibitory effects of BMP9 on the proliferation and migration of lung adenocarcinoma A549 cells. When a co-culture system of A549 cells and bone marrow-derived cells (HS-5) was established, it was shown that HS-5 cells promoted the proliferation and migration of A549 cells, and metastasis and osteoclast-related factors IL-6 and IL-8 were increased in the A549 and HS-5 cells. However, BMP9 inhibited the proliferation and migration of the A549 cells in the bone microenvironment, and decreased the levels of IL-6 and IL-8. In addition, mitogen-activated protein kinase (MAPK/ERK) and nuclear factor-κB (NF-κB) signaling pathway may be involved in these effects.

Antiproliferative and Antioxidant Effects of Withania coagulans Extract on Benign Prostatic Hyperplasia in Rats

Background:

Benign prostate hyperplasia (BPH) is a common urological disorder in elderly men. Phytotherapy is frequently used to alleviate the symptoms of this condition.

Objectives:

The present study investigated the effect of Withania coagulans extract (WCE), which is known to have antioxidant, anti-inflammatory, antihyperglycemic, and anti-cancer properties, on testosterone-induced BPH in rats.

Materials and Methods:

Forty Wistar rats were divided into five groups (each n = 8): the control group, the untreated BPH group, and three WCE-treated groups (WCE250, 500, and 1000). BPH was induced with 3 mg/kg subcutaneous injections of testosterone propionate for four weeks. WCE was concomitantly administrated by oral gavage. At the end of the induction schedule, the animals were sacrificed and their prostate glands were dissected, weighed, and fixed for histological examination (H&E and proliferating cell nuclear antigen [PCNA] staining). Half of each sample was prepared for measurement of malondialdehyde (MDA) and total antioxidant capacity (TAC) levels in the prostate.

Results:

The present study revealed that BPH caused elevation of MDA levels, suppression of TAC levels, and increased PCNA expression in the prostate gland. Interestingly, in a dose-dependent manner, WCE caused decreased MDA levels and increased TAC levels in the prostate gland, compared to the untreated BPH group. Histopathological examinations showed a reduction in PCNA expression in the prostate epithelium of the WCE animals.

Conclusions:

W. coagulans inhibits the development of BPH can be useful for the treatment of this condition.

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.

The promise of recombinant BMP ligands and other approaches targeting BMPR-II in the treatment of pulmonary arterial hypertension

Human genetic discoveries offer a powerful method to implicate pathways of major importance to disease pathobiology and hence provide targets for pharmacological intervention. The genetics of pulmonary arterial hypertension (PAH) strongly implicates loss-of-function of the bone morphogenetic protein type II receptor (BMPR-II) signalling pathway and moreover implicates the endothelial cell as a central cell type involved in disease initiation. We and others have described several approaches to restore BMPR-II function in genetic and non-genetic forms of PAH. Of these, supplementation of endothelial BMP9/10 signalling with exogenous recombinant ligand has been shown to hold considerable promise as a novel large molecule biopharmaceutical therapy. Here, we describe the mechanism of action and discuss potential additional effects of BMP ligand therapy.

BMP9 Crosstalk with the Hippo Pathway Regulates Endothelial Cell Matricellular and Chemokine Responses

Endoglin is a type III TGFβ auxiliary receptor that is upregulated in endothelial cells during angiogenesis and, when mutated in humans, results in the vascular disease hereditary hemorrhagic telangiectasia (HHT). Though endoglin has been implicated in cell adhesion, the underlying molecular mechanisms are still poorly understood. Here we show endoglin expression in endothelial cells regulates subcellular localization of zyxin in focal adhesions in response to BMP9. RNA knockdown of endoglin resulted in mislocalization of zyxin and altered formation of focal adhesions. The mechanotransduction role of focal adhesions and their ability to transmit regulatory signals through binding of the extracellular matrix are altered by endoglin deficiency. BMP/TGFβ transcription factors, SMADs, and zyxin have recently been implicated in a newly emerging signaling cascade, the Hippo pathway. The Hippo transcription coactivator, YAP1 (yes-associated protein 1), has been suggested to play a crucial role in mechanotransduction and cell-cell contact. Identification of BMP9-dependent nuclear localization of YAP1 in response to endoglin expression suggests a mechanism of crosstalk between the two pathways. Suppression of endoglin and YAP1 alters BMP9-dependent expression of YAP1 target genes CCN1 (cysteine-rich 61, CYR61) and CCN2 (connective tissue growth factor, CTGF) as well as the chemokine CCL2 (monocyte chemotactic protein 1, MCP-1). These results suggest a coordinate effect of endoglin deficiency on cell matrix remodeling and local inflammatory responses. Identification of a direct link between the Hippo pathway and endoglin may reveal novel mechanisms in the etiology of HHT.

Loss of GDF10/BMP3b as a prognostic marker collaborates with TGFBR3 to enhance chemotherapy resistance and epithelial-mesenchymal transition in oral squamous cell carcinoma

Growth differentiation factor-10 (GDF10), commonly referred as BMP3b, is a member of the transforming growth factor-β (TGF-β) superfamily. GDF10/BMP3b has been considered as a tumor suppressor, however, little is known about the molecular mechanism of its roles in tumor suppression in oral cancer. Clinical significance of GDF10 downregulation in oral squamous cell carcinoma (OSCC) was evaluated using three independent cohorts of OSCC patients. The molecular mechanisms of GDF10 in the suppression of cell survival, cell migration/invasion and epithelial-mesenchymal transition (EMT) were investigated by using oral cancer cell lines. The present study shows that GDF10 is downregulated during oral carcinogenesis, and GDF10 expression is also an independent risk factor for overall survival of OSCC patients. Overexpression of GDF10 attenuates cell proliferation, transformation, migration/invasion, and EMT. GDF10-inhibited EMT is mediated by ERK signaling but not by typical TGF-β signaling. In addition, overexpression of GDF10 promotes DNA damage-induced apoptosis and sensitizes the response to all-trans retinoic acid (ATRA) and camptothecin (CPT). Intriguingly, the expression of GDF10 is induced by type III TGF-β receptor (TGFBR3) through TGF-β-SMAD2/3 signaling. Our findings suggest that TGFBR3 is an upstream activator of GDF10 expression and they share the same signaling to inhibit EMT and migration/invasion. These results support that GDF10 acts as a hinge to collaborate with TGFBR3 in the transition of EMT-MET program. Taken together, we illustrated the clinical significance and the molecular mechanisms of tumor-suppressive GDF10 in OSCC.

BMP9 regulates cross-talk between breast cancer cells and bone marrow-derived mesenchymal stem cells

PURPOSE

Breast cancer cells frequently metastasize to distant organs, including bone. Interactions between breast cancer cells and the bone microenvironment are known to enhance tumor growth and osteolytic damage. Here we investigated whether BMP9 (a secretary protein) may change the bone microenvironment and, by doing so, regulate the cross-talk between breast cancer cells and bone marrow-derived mesenchymal stem cells.

METHODS

After establishing a co-culture system composed of MDA-MB-231 breast cancer cells and HS-5 bone marrow-derived mesenchymal stem cells, and exposure of this system to BMP9 conditioned media, we assessed putative changes in migration and invasion capacities of MDA-MB-231 cells and concomitant changes in osteogenic marker expression in HS-5 cells and metastases-related genes in MDA-MB-231 cells.

RESULTS

We found that BMP9 can inhibit the migration and invasion of MDA-MB-231 cells, and promote osteogenesis and proliferation of HS-5 cells, in the co-culture system. We also found that the BMP9-induced inhibition of migration and invasion of MDA-MB-231 cells may be caused by a decreased RANK ligand (RANKL) secretion by HS-5 cells, leading to a block in the AKT signaling pathway.

CONCLUSIONS

From our data we conclude that BMP9 inhibits the migration and invasion of breast cancer cells, and promotes the osteoblastic differentiation and proliferation of bone marrow-derived mesenchymal stem cells by regulating cross-talk between these two types of cells through the RANK/RANKL signaling axis.

Apoptosis and KI 67 index correlate with preoperative chemotherapy efficacy and better predict the survival of gastric cancer patients with combined therapy

PURPOSE

T he correlation of apoptotic and proliferation index with preoperative chemotherapy efficacy was investigated. Their prognostic value was also explored.

METHODS

167 patients were enrolled, curative gastrectomy and D2 lymphadenectomy were performed, and a total of 12 cycles of perioperative mFOLFOX7 chemotherapy was recommended. Apoptosis index (AI) and Ki67 index (KI) in surgical specimens were detected.

RESULTS

Apoptosis index, KI and AI/KI were significantly different between patients received perioperative chemotherapy and surgery (CS group, n = 84) and those who received only surgery and postoperative chemotherapy (S group, n = 83). In the CS group, number of patients who received 2, 4, 6 cycles of preoperative chemotherapy were, respectively, 28, 53 and 3. AI, KI and AI/KI were closely related to pathological response. Cutoff value of AI and AI/KI for response separated CS group patients into two subgroups with significant different prognosis and picked up more potential responders than pathological evaluation, especially in pathological response evaluation grade 1a–b.

CONCLUSIONS

Apoptosis index, KI and AI/KI are significantly related to chemotherapy efficacy and prognosis of gastric cancer patients who received perioperative chemotherapy and radical gastrectomy. They could be used in combination with pathological response evaluation to distinguish more potential responders.

BMP9 inhibits proliferation and metastasis of HER2-positive SK-BR-3 breast cancer cells through ERK1/2 and PI3K/AKT pathways

Bone morphogenetic protein 9 (BMP9), a member of TGF-β superfamily, is reported to inhibit the growth and migration of prostate cancer, osteosarcoma and triple-negative MDA-MB-231 breast cancer cells. However, little is known about the effect of on the biological behaviors of HER2-positive SK-BR-3 breast cancer cells and the underlying mechanisms. This study aimed to investigate the effects of BMP9 on the proliferation and metastasis of SK-BR-3 cells with BMP9 over-expression or BMP9 down-regulated expression. Results indicated that exogenously expressed BMP9 inhibited the proliferation and metastasis of SK-BR-3 cells while decreased endogenous BMP9 expression in SK-BR-3 cells promoted the proliferation and migration of breast cancer cells in vitro and in vivo. In SK-BR-3 cells with BMP9 over-expression, the phosphorylation of HER2, ERK1/2 and AKT was markedly suppressed and the HER2 expression decreased at both mRNA and protein levels, while opposite results were observed in SK-BR-3 cells with BMP9 knock down. When the phosphorylation of ERK1/2 and PI3K/AKT was inhibited by PD98059 and LY294002, respectively, the decreased proliferation and invasion induced by BMP9 knock down were eliminated. These findings suggest that BMP9 can inhibit the proliferation and metastasis of SK-BR-3 cells via inactivating ERK1/2 and PI3K/AKT signaling pathways. Thus, BMP9 may serve as a useful agent in the treatment of HER-2 positive breast cancer.

Bone morphogenetic protein-9 suppresses growth of myeloma cells by signaling through ALK2 but is inhibited by endoglin

Multiple myeloma is a malignancy of plasma cells predominantly located in the bone marrow. A number of bone morphogenetic proteins (BMPs) induce apoptosis in myeloma cells in vitro, and with this study we add BMP-9 to the list. BMP-9 has been found in human serum at concentrations that inhibit cancer cell growth in vitro. We here show that the level of BMP-9 in serum was elevated in myeloma patients (median 176 pg/ml, range 8–809) compared with healthy controls (median 110 pg/ml, range 8–359). BMP-9 was also present in the bone marrow and was able to induce apoptosis in 4 out of 11 primary myeloma cell samples by signaling through ALK2. BMP-9-induced apoptosis in myeloma cells was associated with c-MYC downregulation. The effects of BMP-9 were counteracted by membrane-bound (CD105) or soluble endoglin present in the bone marrow microenvironment, suggesting a mechanism for how myeloma cells can evade the tumor suppressing activity of BMP-9 in multiple myeloma.

MB109 as bioactive human bone morphogenetic protein-9 refolded and purified from E. coli inclusion bodies

Background

The development of chemical refolding of transforming growth factor-beta (TGF-β) superfamily ligands has been instrumental to produce the recombinant proteins for biochemical studies and exploring the potential of protein therapeutics. The osteogenic human bone morphogenetic protein-2 (hBMP-2) and its Drosophila DPP homolog were the early successful cases of refolding into functional form. Despite the similarity in their three dimensional structure and amino acid sequences, several other TGF-β superfamily ligands could not be refolded readily by the same methods.

Results

Here, we report a comprehensive study on the variables of a rapid-dilution refolding method, including the concentrations of protein, salt, detergent and redox agents, pH, refolding duration and the presence of aggregation suppressors and host-cell contaminants, in order to identify the optimal condition to refold human BMP-9 (hBMP-9). To produce a recombinant form of hBMP-9 in E. coli cells, a synthetic codon-optimized gene was designed to encode the mature domain of hBMP-9 (Ser320 – Arg429) directly behind the first methionine, which we herein referred to as MB109. An effective purification scheme was also developed to purify the refolded MB109 to homogeneity with a final yield of 7.8 mg from 100 mg of chromatography-purified inclusion bodies as a starting material. The chemically refolded MB109 binds to ALK1, ActRIIb and BMPRII receptors with relatively high affinity as compared to other Type I and Type II receptors based on surface plasmon resonance analysis. Smad1-dependent luciferase assay in C2C12 cells shows that the MB109 has an EC₅₀ of 0.61 ng/mL (25 pM), which is nearly the same as hBMP-9.

Conclusion

MB109 is prone to be refolded as non-functional dimer and higher order multimers in most of the conditions tested, but bioactive MB109 dimer can be refolded with high efficiency in a narrow window, which is strongly dependent on the pH, refolding duration, the presence of aggregation suppressors and the concentrations of protein, salt and detegent. These results add to the current understanding of producing recombinant TGF-β superfamily ligands in the microbial E. coli system. An application of the technique to produce a large number of synthetic TGF-β chimeras for activity screen is also discussed.

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.

Prostate cancer: the need for biomarkers and new therapeutic targets

Prostate cancer (PCa) incidence and mortality have decreased in recent years. Nonetheless, it remains one of the most prevalent cancers in men, being a disquieting cause of men's death worldwide. Changes in many cell signaling pathways have a predominant role in the onset, development, and progression of the disease. These include prominent pathways involved in the growth, apoptosis, and angiogenesis of the normal prostate gland, such as androgen and estrogen signaling, and other growth factor signaling pathways. Understanding the foundations of PCa is leading to the discovery of key molecules that could be used to improve patient management. The ideal scenario would be to have a panel of molecules, preferably detectable in body fluids, that are specific and sensitive biomarkers for PCa. In the early stages, androgen deprivation is the gold standard therapy. However, as the cancer progresses, it eventually becomes independent of androgens, and hormonal therapy fails. For this reason, androgen-independent PCa is still a major therapeutic challenge. By disrupting specific protein interactions or manipulating the expression of some key molecules, it might be possible to regulate tumor growth and metastasis formation, avoiding the systemic side effects of current therapies. Clinical trials are already underway to assess the efficacy of molecules specially designed to target key proteins or protein interactions. In this review, we address that recent progress made towards understanding PCa development and the molecular pathways underlying this pathology. We also discuss relevant molecular markers for the management of PCa and new therapeutic challenges.

Death-associated protein-3, DAP-3, correlates with preoperative chemotherapy effectiveness and prognosis of gastric cancer patients following perioperative chemotherapy and radical gastrectomy

Background:

DAP3 is a member of the death-associated protein (DAP) family and is characterised by proapoptotic function. It is involved in both exogenous and endogenous apoptotic pathways. In our previous studies, apoptotic level was found to be correlated with the effectiveness of preoperative chemotherapy. The effectiveness of preoperative chemotherapy was also associated with the overall effectiveness of the combined therapy and prognosis. The present study aimed to investigate the role of DAP3 in the evaluation of preoperative chemotherapy effectiveness and its ability to predict prognosis in gastric cancer.

Methods:

Quantitative PCR and immunohistochemistry staining were performed in 87 patients who received combined therapy. Knockdown of DAP3 was conducted in gastric cancer cell lines to investigate its impact on cell growth, migration, adhesion and invasion. Tolerance to chemotherapy agents was determined by assessing apoptosis and caspase-3.

Results:

Higher DAP3 expression in gastric tumours was correlated with better prognosis. Knockdown of DAP3 expression promoted cell migration and enhanced resistance to chemotherapy by inhibiting apoptosis.

Conclusion:

DAP3 is a potential molecular marker for response to preoperative chemotherapy and for predicting prognosis in gastric cancer patients treated with neoadjuvant chemotherapy and gastrectomy.

Bone morphogenetic protein-9 inhibits lymphatic vessel formation via activin receptor-like kinase 1 during development and cancer progression

Lymphatic vessels (LVs) play critical roles in the maintenance of fluid homeostasis and in pathological conditions, including cancer metastasis. Although mutations in ALK1, a member of the transforming growth factor (TGF)-β/bone morphogenetic protein (BMP) receptor family, have been linked to hereditary hemorrhagic telangiectasia, a human vascular disease, the roles of activin receptor-like kinase 1 (ALK-1) signals in LV formation largely remain to be elucidated. We show that ALK-1 signals inhibit LV formation, and LVs were enlarged in multiple organs in Alk1-depleted mice. These inhibitory effects of ALK-1 signaling were mediated by BMP-9, which decreased the number of cultured lymphatic endothelial cells. Bmp9-deficient mouse embryos consistently exhibited enlarged dermal LVs. BMP-9 also inhibited LV formation during inflammation and tumorigenesis. BMP-9 downregulated the expression of the transcription factor prospero-related homeobox 1, which is necessary to maintain lymphatic endothelial cell identity. Furthermore, silencing prospero-related homeobox 1 expression inhibited lymphatic endothelial cell proliferation. Our findings reveal a unique molecular basis for the physiological and pathological roles of BMP-9/ALK-1 signals in LV formation.

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.

Bone morphogenetic protein 9 overexpression reduces osteosarcoma cell migration and invasion

Transforming growth factor-β (TGF-β) is known to promote tumor migration and invasion. Bone morphogenetic proteins (BMPs) are members of the TGF-β family expressed in a variety of human carcinoma cell lines. The role of bone morphogenetic protein 9 (BMP9), the most powerful osteogenic factor, in osteosarcoma (OS) progression has not been fully clarified. The expression of BMP9 and its receptors in OS cell lines was analyzed by RT-PCR. We found that BMP9 and its receptors were expressed in OS cell lines. We further investigated the influence of BMP9 on the biological behaviors of OS cells. BMP9 overexpression in the OS cell lines 143B and MG63 inhibited in vitro cell migration and invasion. We further investigated the expression of a panel of cancer-related genes and found that BMP9 overexpression increased the phosphorylation of Smad1/5/8 proteins, increased the expression of ID1, and reduced the expression and activity of matrix metalloproteinase 9 (MMP9) in OS cells. BMP9 silencing induced the opposite effects. We also found that BMP9 may not affect the chemokine (C-X-C motif) ligand 12 (CXCL12)/C-X-C chemokine receptor type 4 (CXCR4) axis to regulate the invasiveness and metastatic capacity of OS cells. Interestingly, CXCR4 was expressed in both 143B and MG63 cells, while CXCL12 was only detected in MG63 cells. Taken together, we hypothesize that BMP9 inhibits the migration and invasiveness of OS cells through a Smad-dependent pathway by downregulating the expression and activity of MMP9.

BMP signaling in mesenchymal stem cell differentiation and bone formation

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily and have diverse functions during development and organogenesis. BMPs play a major role in skeletal development and bone formation, and disruptions in BMP signaling cause a variety of skeletal and extraskeletal anomalies. Several knockout models have provided insight into the mechanisms responsible for these phenotypes. Proper bone formation requires the differentiation of osteoblasts from mesenchymal stem cell (MSC) precursors, a process mediated in part by BMP signaling. Multiple BMPs, including BMP2, BMP6, BMP7 and BMP9, promote osteoblastic differentiation of MSCs both in vitro and in vivo. BMP9 is one of the most osteogenic BMPs yet is a poorly characterized member of the BMP family. Several studies demonstrate that the mechanisms controlling BMP9-mediated osteogenesis differ from other osteogenic BMPs, but little is known about these specific mechanisms. Several pathways critical to BMP9-mediated osteogenesis are also important in the differentiation of other cell lineages, including adipocytes and chondrocytes. BMP9 has also demonstrated translational promise in spinal fusion and bone fracture repair. This review will summarize our current knowledge of BMP-mediated osteogenesis, with a focus on BMP9, by presenting recently completed work which may help us to further elucidate these pathways.

Preventing MEK1 activation influences the responses of human osteosarcoma cells to bone morphogenetic proteins 2 and 9

It was recently suggested that bone morphogenetic protein (BMP)-2 may be useful for treating osteosarcoma cells. BMP-9, which has been patented to treat breast and prostate cancers, has a higher osteoinductive potential than BMP-2. Peptides derived from the knuckle epitope of BMPs (pBMPs) also induced osteogenic differentiation. However, the effect of BMP-9 and pBMPs on osteosarcoma cells is unclear. We analyzed the effects of BMP-2, BMP-9, pBMP-2, and pBMP-9 on the behavior of human MG-63 and SaOS-2 osteosarcoma cells. An inhibitor of MEK1 activation (PD98059) that prevents downstream extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and a specific inhibitor of p38 were also used as mitogen activated protein kinase-targeting therapy is being investigated as a treatment modality for osteosarcoma. BMP-2 and BMP-9 (1.92 nmol/l) induced the phosphorylation of Smad1/5/8 in both osteosarcoma cells within 1 h but had different effects on mitogen activated protein kinase pathways. Whereas BMP-2 mainly activated ERK1/2, BMP-9 phosphorylated p38 within 1 h. pBMP-2 did not activate either the Smad or ERK/p38, whereas pBMP-9, like BMP-9, induced both Smad1/5/8 and p38 phosphorylation. p38 activation by BMP-9 or pBMP-9 was also enhanced by PD98059. However, BMP-2 or BMP-9 increased the amounts of distal-less homeobox 5 and Osterix mRNAs in SaOS-2 cells within 6 h, whereas pBMP-9 had no effect. PD98059 promoted the highest level of Osterix mRNA in SaOS-2 cells incubated with BMP-2 or BMP-9, whereas p38 inhibitor had no effect. Furthermore, PD98059 induced the lowest proliferation of MG-63 cells incubated with BMP-2, whereas p38 inhibitor did not affect the proliferation of either osteosarcoma cell line. Therefore a combination of BMP-2 or BMP-9 and an inhibitor of MEK1 may be a promising tool for regulating osteosarcoma cell behavior.

Bone morphogenetic protein-9 induces epithelial to mesenchymal transition in hepatocellular carcinoma cells

Epithelial-mesenchymal transition (EMT) is an important mechanism to initiate cancer invasion and metastasis. Bone morphogenetic protein (BMP)-9 is a member of the transforming growth factor (TGF)-β superfamily. It has been suggested to play a role in cancer development in some non-hepatic tumors. In the present study, two hepatocellular carcinoma (HCC) lines, HLE and HepG2, were treated with BMP-9 in vitro, and phenotypic changes and cell motility were analyzed. In situ hybridization (ISH) and immunohistochemical analyses were performed with human HCC tissue samples in order to assess expression levels of BMP-9. In vivo, BMP-9 protein and mRNA were expressed in all the tested patients to diverse degrees. At the protein level, mildly positive (1 + ) BMP-9 staining could be observed in 25/41 (61%), and moderately to strongly positive (2 + ) in 16/41 (39%) of the patients. In 27/41 (65%) patients, the BMP-9 protein expression level was consistent with the mRNA expression level as measured by ISH. In those patients with 2 + protein level, nuclear pSmad1 expression in cancer cells was also significantly increased. Expression of BMP-9 was positively related to nuclear Snail expression and reversely correlated to cell surface E-cadherin expression, although this did not reach statistical significance. Expression levels of BMP-9 were significantly associated with the T stages of the investigated tumors and high levels of BMP-9 were detected by immunofluorescence especially at the tumor borders in samples from an HCC mouse model. In vitro, BMP-9 treatment caused a reduction of E-cadherin and ZO-1 and an induction of Vimentin and Snail expression. Furthermore, cell migration was enhanced by BMP-9 in both HCC cell lines. These results imply that EMT induced by BMP-9 is related to invasiveness of HCC.

Bone morphogenetic protein-9 activates Smad and ERK pathways and supports human osteoclast function and survival in vitro

BMP-9 is a potent osteogenic factor; however, its effects on osteoclasts, the bone-resorbing cells, remain unknown. To determine the effects of BMP-9 on osteoclast formation, activity and survival, we used human cord blood monocytes as osteoclast precursors that form multinucleated osteoclasts in the presence of RANKL and M-CSF in long-term cultures. BMP-9 did not affect osteoclast formation, but adding BMP-9 at the end of the culture period significantly increased bone resorption compared to untreated cultures, and reduced both the rate of apoptosis and caspase-9 activity. BMP-9 also significantly downregulated the expression of pro-apoptotic Bid, but only after RANKL and M-CSF, which are both osteoclast survival factors, had been eliminated from the culture medium. To investigate the mechanisms involved in the effects of BMP-9, we first showed that osteoclasts expressed some BMP receptors, including BMPR-IA, BMPR-IB, ALK1, and BMPR-II. We also found that BMP-9 was able to induce the phosphorylation of Smad-1/5/8 and ERK 1/2 proteins, but did not induce p38 phosphorylation. Finally, knocking down the BMPR-II receptor abrogated the BMP-9-induced ERK-signaling, as well as the increase in bone resorption. In conclusion, these results show for the first time that BMP-9 directly affects human osteoclasts, enhancing bone resorption and protecting osteoclasts against apoptosis. BMP-9 signaling in human osteoclasts involves the canonical Smad-1/5/8 pathway, and the ERK pathway.

Med19 promotes bone metastasis and invasiveness of bladder urothelial carcinoma via bone morphogenetic protein 2

Bladder cancer (BCa) remained a major health problem. Med19 was related to tumor growth of BCa. Bone morphogenetic proteins (BMPs) were reported to be critical in bone metastasis of cancer. We therefore investigated the relations between Med19 and BMPs in BCa and their effect on bone metastasis of BCa. Bladder cancer cell lines were cultured and interfered with Med19 shRNA and control. Expressions of BMP-1, BMP-2, BMP-4, BMP-5, BMP-6, BMP-7, BMP-9, and BMP-15 were studied between 2 groups. Fifty-two BCa samples were included for immunohistochemical staining of Med19 and BMP-2. Expressions were scored and studied statistically. Invasiveness was studied with Transwell assay. Silencing or Med19 in BCa cells induced altered expressions of BMPs. Increased expressions of BMP-1, BMP-4, BMP-6, BMP-7, and BMP-15 and decreased expressions of BMP-2, BMP-5, and BMP-9 were noticed, but only BMP-2 reached statistical significance. Expressions of Med19 and BMP-2 were significantly higher in cases with bone metastasis and were positively correlated in cases with bone metastasis and muscle invasion. Med19 is a critical factor involved in the invasiveness and promotion of bone metastasis of BCa, possibly via BMP-2.

Repulsive guidance molecule B (RGMB) plays negative roles in breast cancer by coordinating BMP signaling

Repulsive guidance molecules (RGMs) coordinate axon formation and iron homestasis. These molecules are also known as co-receptors of bone morphogenetic proteins (BMPs). However, the role played by RGMs in breast cancer remains unclear. The present study investigated the impact of RGMB on functions of breast cancer cells and corresponding mechanisms. RGMB was knocked down in breast cancer cells by way of an anti-RGMB ribozyme transgene. Knockdown of RGMB resulted in enhanced capacities of proliferation, adhesion, and migration in breast cancer cells. Further investigations demonstrated RGMB knockdown resulted in a reduced expression and activity of Caspase-3, accompanied with better survival in RGMB knockdown cells under serum starvation, which might be induced by its repression on MAPK JNK pathway. Up-regulations of Snai1, Twist, FAK, and Paxillin via enhanced Smad dependent sigaling led to increased capacities of adhesion and migration. Our current data firstly revealed that RGMB may act as a negative regulator in breast cancer through BMP signaling.

Adenovirus-mediated overexpression of BMP-9 inhibits human osteosarcoma cell growth and migration through downregulation of the PI3K/AKT pathway

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily of signaling molecules and have previously been shown to be associated with the biological behavior of osteosarcoma. However, to date the effects and molecular mechanisms of BMP-9 on osteosarcoma progression are unknown. We performed real-time PCR and western blot analysis to characterize the endogenous expression of BMP-9 in osteosarcoma cell lines. We used a recombinant adenovirus expressing BMP-9 (adBMP-9) to infect osteosarcoma cell lines with relatively low endogenous BMP-9 expression to determine the functional relevance of BMP-9 overexpression to osteosarcoma cell growth and migration in vitro and in vivo, and further investigated the expression levels of Ki-67, matrix metallopeptidase-9 (MMP-9), phosphoinositide 3-kinase p85α (PI3Kp85α) and phosphorylated AKT (p-AKT). As a result, osteosarcoma cell proliferation and migration were significantly diminished by adBMP-9, indicated by MTT and wound-healing assays, and cell apoptosis was markedly induced, indicated by Hoechst 33342/PI assay and Annexin V-FITC apoptosis detection. When BMP-9 expression was enhanced, the expression of PI3Kp85α, p-AKT, Ki-67 and MMP-9 was downregulated in osteosarcoma cells. In addition, the tumor volumes in MG-63 and HOS subcutaneous nude mouse models treated with adBMP-9 were significantly smaller compared to those of the ad-GFP group. These results suggested that the enhanced expression of BMP-9 in osteosarcoma cells by adBMP-9 exerted inhibitory effects on growth and migration of osteosarcoma cells possibly via blockade of the PI3K/AKT signaling pathway.