Small molecule inhibitor of the bone morphogenetic protein pathway DMH1 reduces ovarian cancer cell growth

ARF alters PAF1 complex integrity to selectively repress oncogenic transcription programs upon p53 loss

The polymerase associated factor 1 (PAF1) complex (PAF1c) promotes RNA polymerase II (RNA Pol II) transcription at the elongation step; however, how PAF1c transcription activity is selectively regulated during cell fate transitions remains poorly understood. Here, we reveal that the alternative reading frame (ARF) tumor suppressor operates at two levels to restrain PAF1c-dependent oncogenic transcriptional programs upon p53 loss in mouse cells. First, ARF assembles into homo-oligomers to bind the PAF1 subunit to promote PAF1c disassembly, consequently dampening PAF1c interaction with RNA Pol II and PAF1c-dependent transcription. Second, ARF targets the RUNX family transcription factor 1 (RUNX1) to selectively tune gene transcription. Consistently, ARF loss triggers RUNX1- and PAF1c-dependent transcriptional activation of pro-growth ligands (growth differentiation factor/bone morphogenetic protein [GDF/BMP]), promoting a cell-intrinsic GDF/BMP-Smad1/5 axis that aberrantly induce cell growth. Notably, pharmacologic inactivation of GDF/BMP signaling and genetic perturbation of RUNX1 significantly attenuate cell proliferation mediated by dual p53 and ARF loss, offering therapeutic utility. Our data underscore the significance of selective ARF-mediated tumor-suppressive functions through a universal transcriptional regulator.

Nicotinamide adenine dinucleotide kinase promotes lymph node metastasis of NSCLC via activating ID1 expression through BMP pathway

Metastasis is a significant cause of high mortality in lung cancer. Lymph node (LN) metastasis is the most common metastatic pathway in non-small cell lung cancer and the most crucial factor affecting the prognosis of NSCLC. Nevertheless, the molecular mechanism underlying metastasis is unknown. We demonstrated that higher NADK expression suggests worsened survival prognosis, and NADK expression positively correlates with the lymph node metastasis rate and TNM and AJCC stages in NSCLC patients. Moreover, patients with LN metastasis show higher NADK expression than those without LN metastasis. NADK can promote NSCLC progression by enhancing the migration, invasion, lymph node metastasis and growth of NSCLC cells. Mechanistically, NADK inhibits the ubiquitination and degradation of BMPR1A by interacting with Smurf1, further activating the BMPs signalling pathway and promoting ID1 transcription. In conclusion, NADK may be a potential diagnostic indicator and a novel therapeutic target for metastatic NSCLC.

Bone morphogenetic protein signaling is a possible therapeutic target in gynecologic cancer

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor β (TGFβ) superfamily. BMPs play crucial roles in embryogenesis and bone remodeling. Recently, BMP signaling has been found to have diverse effects on different types of tumors. In this review, we summarized the effects of BMP signaling on gynecologic cancer. BMP signaling has tumor-promoting effects on ovarian cancer (OC) and endometrial cancer (EC), whereas it has tumor-suppressing effects on uterine cervical cancer (UCC). Interestingly, EC has frequent gain-of-function mutations in ACVR1, encoding one of the type I BMP receptors, which are also observed in fibrodysplasia ossificans progressiva and diffuse intrinsic pontine glioma. Little is known about the relationship between BMP signaling and other gynecologic cancers. Tumor-promoting effects of BMP signaling in OC and EC are dependent on the promotion of cancer stemness and epithelial-mesenchymal transition (EMT). In accordance, BMP receptor kinase inhibitors suppress the cell growth and migration of OC and EC. Since both cancer stemness and EMT are associated with chemoresistance, BMP signaling activation might also be an important mechanism by which OC and EC patients acquire chemoresistance. Therefore, BMP inhibitors are promising for OC and EC patients even if they become resistant to standard chemotherapy. In contrast, BMP signaling inhibits UCC growth in vitro. However, the in vivo effects of BMP signaling have not been elucidated in UCC. In conclusion, BMP signaling has a variety of functions, depending on the types of gynecologic cancer. Therefore, targeting BMP signaling should improve the treatment of patients with gynecologic cancer.

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

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

Bone Morphogenetic Protein Signaling in Cancer; Some Topics in the Recent 10 Years

Bone morphogenetic proteins (BMPs), members of the transforming growth factor-β (TGF-β) family, are multifunctional cytokines. BMPs have a broad range of functions, and abnormalities in BMP signaling pathways are involved in cancer progression. BMPs activate the proliferation of certain cancer cells. Malignant phenotypes of cancer cells, such as increased motility, invasiveness, and stemness, are enhanced by BMPs. Simultaneously, BMPs act on various cellular components and regulate angiogenesis in the tumor microenvironment. Thus, BMPs function as pro-tumorigenic factors in various types of cancer. However, similar to TGF-β, which shows both positive and negative effects on tumorigenesis, BMPs also act as tumor suppressors in other types of cancers. In this article, we review important findings published in the recent decade and summarize the pro-oncogenic functions of BMPs and their underlying mechanisms. The current status of BMP-targeted therapies for cancers is also discussed.

lncRNA CDKN2A-AS1 facilitates tumorigenesis and progression of epithelial ovarian cancer via modulating the SOSTDC1-mediated BMP-SMAD signaling pathway

Ovarian cancer (OC) is the fifth most common female malignant tumor and the leading cause of cancer-related death in women worldwide. Epithelial ovarian cancer (EOC) is the predominant type of OC. Investigating the mechanism underlying tumorigenesis and progression of EOC is urgent. Our previous research has shown that long non-coding RNAs (lncRNAs) CDKN2A-AS1 is upregulated in EOC tissues and cells. Furthermore, we have predicted that CDKN2A-AS1 is associated with the bone morphogenetic protein (BMP)-SMAD signaling pathway, which is negatively regulated by the sclerostin domain containing 1 (SOSTDC1). Therefore, we conjecture that the CDKN2A-AS1 regulate BMP-SMAD signaling pathway via interacting with SOSTDC1, which need more investigation. Moreover, the functions of the BMP-SMAD signaling pathway and the SOSTDC1 on EOC are still unclear. Herein, we unearthed that CDKN2A-AS1, BMP2/4/7, SMAD1/5/9 and phosphorylation of SMAD1/5/9 (p-SMAD1/5/9) were upregulated in EOC tissues and cells, whereas SOSTDC1 was downregulated in EOC tissues and cells. We firstly demonstrated that CDKN2A-AS1 bound directly with the SOSTDC1. CDKN2A-AS1 downregulated the expression of SOSTDC1, but upregulated the expression of BMP2/4/7, SMAD1/5/9, and p-SMAD1/5/9. CDKN2A-AS1 promoted the proliferation, migration, invasion of EOC cells and tumor growth in vivo, whereas SOSTDC1 inhibited the proliferation, migration, invasion of EOC cells. Knockdown SOSTDC1 rescued the inhibitory effect of si-lncRNA CDKN2A-AS1 on the EOC cells proliferation, migration and invasion. These results demonstrated that CDKN2A-AS1activated the BMP-SMAD signaling pathway by directly bind with SOSTDC1 to promote EOC tumor growth. CDKN2A-AS1/SOSTDC1 axis may provide a novel therapeutic strategy for EOC treatment.

BMP signaling is a therapeutic target in ovarian cancer

BMP signaling has been found to have tumor-promoting as well as tumor-suppressing effects in different types of tumors. In this study, we investigated the effects of BMP signaling and of BMP inhibitors on ovarian cancer (OC) cells in vitro and in vivo. High expression of BMP receptor 2 (BMPR2) correlated with poor overall survival of OC patients in the TCGA dataset. Both BMP2 and BMPR2 enhanced OC cell proliferation, whereas BMP receptor kinase inhibitors inhibited OC cell growth in cell culture as well as in a mouse model. BMP2 also augmented sphere formation, migration, and invasion of OC cells, and induced EMT. High BMP2 expression was observed after chemotherapy of OC patients in the GSE109934 dataset. In accordance, carboplatin, used for the treatment of OC patients, increased BMP2 secretion from OC cells, and induced EMT partially via activation of BMP signaling. Our data suggest that BMP signaling has tumor-promoting effects in OC, and that BMP inhibitors might be useful therapeutic agents for OC patients. Considering that carboplatin treatment augmented BMP2 secretion, the possibility to use a combination of BMP inhibitors and carboplatin in the treatment of OC patients, would be worth exploring.

Discovery, synthesis and characterization of a series of 7-aryl-imidazo[1,2-a]pyridine-3-ylquinolines as activin-like kinase (ALK) inhibitors

The activin-like kinases are a family of kinases that play important roles in a variety of disease states. Of this class of kinases, ALK2, has been shown by a gain-of-function to be the primary driver of the childhood skeletal disease fibrodysplasia ossificans progressiva (FOP) and more recently the pediatric cancer diffuse intrinsic pontine glioma (DIPG). Herein, we report our efforts to identify a novel imidazo[1,2-a]pyridine scaffold as potent inhibitors of ALK2 with good in vivo pharmacokinetic properties suitable for future animal studies.

Activin/Nodal signaling mediates dorsal-ventral axis formation before third quartet formation in embryos of the annelid Chaetopterus pergamentaceus

BACKGROUND

The clade of protostome animals known as the Spiralia (e.g., mollusks, annelids, nemerteans and polyclad flatworms) shares a highly conserved program of early development. This includes shared arrangement of cells in the early-stage embryo and fates of descendant cells into embryonic quadrants. In spiralian embryos, a single cell in the D quadrant functions as an embryonic organizer to pattern the body axes. The precise timing of the organizing signal and its cellular identity varies among spiralians. Previous experiments in the annelid Chaetopterus pergamentaceus Cuvier, 1830 demonstrated that the D quadrant possesses an organizing role in body axes formation; however, the molecular signal and exact cellular identity of the organizer were unknown.

RESULTS

In this study, the timing of the signal and the specific signaling pathway that mediates organizing activity in C. pergamentaceus was investigated through short exposures to chemical inhibitors during early cleavage stages. Chemical interference of the Activin/Nodal pathway but not the BMP or MAPK pathways results in larvae that lack a detectable dorsal-ventral axis. Furthermore, these data show that the duration of organizing activity encompasses the 16 cell stage and is completed before the 32 cell stage.

CONCLUSIONS

The timing and molecular signaling pathway of the C. pergamentaceus organizer is comparable to that of another annelid, Capitella teleta, whose organizing signal is required through the 16 cell stage and localizes to micromere 2d. Since C. pergamentaceus is an early branching annelid, these data in conjunction with functional genomic investigations in C. teleta hint that the ancestral state of annelid dorsal-ventral axis patterning involved an organizing signal that occurs one to two cell divisions earlier than the organizing signal identified in mollusks, and that the signal is mediated by Activin/Nodal signaling. Our findings have significant evolutionary implications within the Spiralia, and furthermore suggest that global body patterning mechanisms may not be as conserved across bilaterians as was previously thought.

Loss of Myeloid BMPR1a Alters Differentiation and Reduces Mouse Prostate Cancer Growth

The Bone Morphogenetic Protein (BMP) pathway is a member of the TGFβ signaling family and has complex roles in cancer. BMP signaling is rarely mutated and can be frequently overexpressed in many human cancers. The dichotomous role of BMPs as both tumor promoters and suppressors appears to be largely context based in both the cancer cell and the surrounding microenvironment. Myeloid cells including macrophages and neutrophils have been shown to be tumor promoting when stimulated from BMPs. We found that conditional deletion of BMPR1a in myeloid cells (LysMCre) restricts tumor progression in a syngeneic mouse prostate cancer model. Specific changes occurred in myeloid cells both in tumor bearing mice and tumor naïve mice throughout multiple tissues. We profiled myeloid subsets in the bone marrow, spleen and primary tumor and found myeloid BMPR1a loss altered the differentiation and lineage capability of distinct populations by histologic, flow cytometry and high dimensional mass cytometry analysis. We further confirmed the requirement for BMP signaling with pharmacologic inhibition of THP-1 and Raw264.7 activated into M2 macrophages with the BMP inhibitor DMH1. M2 polarized primary bone marrow derived cells from LysMCre BMPR1a knockout mice indicated a distinct requirement for BMP signaling in myeloid cells during M2 activation. These results indicate a unique necessity for BMP signaling in myeloid cells during tumor progression.

System-level responses to cisplatin in pro-apoptotic stages of breast cancer MCF-7 cell line

Cisplatin ceases cell division and induces apoptosis in cancer cell lines. It is well established that cisplatin alters the expression of many genes involved in several cellular processes and pathways including transcription, p53 signaling pathway, and apoptosis. However, system-wide responses to cisplatin in breast cancer cell lines have not been studied. Therefore, we have used a network analysis approach to unveil such responses at early stages of drug treatment. To do this, we have first identified those genes that are responding to cisplatin treatment in MCF-7 cell line. Network and gene ontology analyses were then employed to uncover the molecular pathways affected by cisplatin treatment. Then the results obtained from cisplatin-treated MCF7 cell line were compared to those obtained from other cancer cell lines at comparable time points. In conclusion, we found that ADCY9, GSK3B, MAPK14, NCK1, NCOA2, PIK3CA, PIK3CB, PTK2, RHOB act as hub genes in the cisplatin-responsive regulatory network at the pro-apoptotic stages. The results could be useful in finding new drugs to target these genes in order to obtain similar responses.

Epithelial‑mesenchymal transition induced by bone morphogenetic protein 9 hinders cisplatin efficacy in ovarian cancer cells

Bone morphogenetic protein 9 (BMP9) belongs to the transforming growth factor-β (TGF-β) superfamily, and has been reported to promote cancer cell proliferation and epithelial-mesenchymal transition (EMT). Cisplatin (DDP) is the first line treatment for ovarian cancer. However, initiation of EMT confers insensitivity to chemotherapy. The present study aimed to verify and examine the mechanisms underlying the effects of BMP9 on treatment with DDP for ovarian cancer. Prior to treatment with DDP, ovarian cancer cells were exposed to BMP9 for 3 days. Following this, cell viability, apoptosis rate and the extent of DNA damage were evaluated to compare the effects of DDP on BMP9-pretreated and non-pretreated ovarian cancer cells. In addition, EMT marker expression was evaluated by western blotting and immunofluorescence. The results demonstrated that BMP9 pretreatment inhibited the cytotoxicity of DDP on ovarian cancer cells. Additionally, BMP9-pretreated ovarian cancer cells had downregulated expression of the epithelial marker E-cadherin, which was accompanied by an upregulation of the mesenchymal markers N-cadherin, Snail, Slug, and Twist. Taken together, the findings of the present study indicated that BMP9 conferred resistance to DDP in ovarian cancer cells by inducing EMT. The present study provided valuable insight into the mechanisms of chemotherapy in ovarian cancer and highlighted the potential of BMP9 as a novel therapeutic target for improving cisplatin chemosensitivity.

Polysiphonia japonica Extract Attenuates Palmitate-Induced Toxicity and Enhances Insulin Secretion in Pancreatic Beta-Cells

Beta-cell loss is a major cause of the pathogenesis of diabetes. Elevated levels of free fatty acids may contribute to the loss of β-cells. Using a transgenic zebrafish, we screened ~50 seaweed crude extracts to identify materials that protect β-cells from free fatty acid damage. We found that an extract of the red seaweed Polysiphonia japonica (PJE) had a β-cell protective effect. We examined the protective effect of PJE on palmitate-induced damage in β-cells. PJE was found to preserve cell viability and glucose-induced insulin secretion in a pancreatic β-cell line, Ins-1, treated with palmitate. Additionally, PJE prevented palmitate-induced insulin secretion dysfunction in zebrafish embryos and mouse primary islets and improved insulin secretion in β-cells against palmitate treatment. These findings suggest that PJE protects pancreatic β-cells from palmitate-induced damage. PJE may be a potential therapeutic functional food for diabetes.

Structural basis for the potent and selective binding of LDN-212854 to the BMP receptor kinase ALK2

Individuals with the rare developmental disorder fibrodysplasia ossificans progressiva (FOP) experience disabling heterotopic ossification caused by a gain of function mutation in the intracellular region of the BMP type I receptor kinase ALK2, encoded by the gene ACVR1. Small molecule BMP type I receptor inhibitors that block this ossification in FOP mouse models have been derived from the pyrazolo[1,5-a]pyrimidine scaffold of dorsomorphin. While the first derivative LDN-193189 exhibited pan inhibition of BMP receptors, the more recent compound LDN-212854 has shown increased selectivity for ALK2. Here we solved the crystal structure of ALK2 in complex with LDN-212854 to define how its binding interactions compare to previously reported BMP and TGFβ receptor inhibitors. LDN-212854 bound to the kinase hinge region as a typical type I ATP-competitive inhibitor with a single hydrogen bond to ALK2 His286. Specificity arising from the 5-quinoline moiety was associated with a distinct pattern of water-mediated hydrogen bonds involving Lys235 and Glu248 in the inactive conformation favoured by ALK2. The structure of this complex provides a template for the design of future ALK2 inhibitors under development for the treatment of FOP and other related conditions of heterotopic ossification.

Utilizing Zebrafish to Identify Anti-(Lymph)Angiogenic Compounds for Cancer Treatment: Promise and Future Challenges

Cancer metastasis which predominantly occurs through blood and lymphatic vessels, is the leading cause of death in cancer patients. Consequently, several anti-angiogenic agents have been approved as therapeutic agents for human cancers such as metastatic renal cell carcinoma. Also, anti-lymphangiogenic drugs such as monoclonal antibodies VGX-100 and IMC-3C5 have undergone phase I clinical trials for advanced and metastatic solid tumors. Although anti-tumor-associated angiogenesis has proven to be a promising therapeutic strategy for human cancers, this approach is fraught with toxicities and development of drug resistance. This emphasizes the need for alternative anti-(lymph)angiogenic drugs. The use of zebrafish has become accepted as an established model for high-throughput screening, vascular biology, and cancer research. Importantly, various zebrafish transgenic lines have now been generated that can readily discriminate different vascular compartments. This now enables detailed in vivo studies that are relevant to both human physiological and tumor (lymph)angiogenesis to be conducted in zebrafish. This review highlights recent advancements in the zebrafish anti-vascular screening platform and showcases promising new anti-(lymph)angiogenic compounds that have been derived from this model. In addition, this review discusses the promises and challenges of the zebrafish model in the context of anti-(lymph)angiogenic compound discovery for cancer treatment.

Ligand-activated BMP signaling inhibits cell differentiation and death to promote melanoma

Oncogenomic studies indicate that copy number variation (CNV) alters genes involved in tumor progression; however, identification of specific driver genes affected by CNV has been difficult, as these rearrangements are often contained in large chromosomal intervals among several bystander genes. Here, we addressed this problem and identified a CNV-targeted oncogene by performing comparative oncogenomics of human and zebrafish melanomas. We determined that the gene encoding growth differentiation factor 6 (GDF6), which is the ligand for the BMP family, is recurrently amplified and transcriptionally upregulated in melanoma. GDF6-induced BMP signaling maintained a trunk neural crest gene signature in melanomas. Additionally, GDF6 repressed the melanocyte differentiation gene MITF and the proapoptotic factor SOX9, thereby preventing differentiation, inhibiting cell death, and promoting tumor growth. GDF6 was specifically expressed in melanomas but not melanocytes. Moreover, GDF6 expression levels in melanomas were inversely correlated with patient survival. Our study has identified a fundamental role for GDF6 and BMP signaling in governing an embryonic cell gene signature to promote melanoma progression, thus providing potential opportunities for targeted therapy to treat GDF6-positive cancers.

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

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

Differential molecular regulation of processing and membrane expression of Type-I BMP receptors: implications for signaling

The Type-I bone morphogenetic protein receptors (BMPRs), BMPR1A and BMPR1B, present the highest sequence homology among BMPRs, suggestive of functional similitude. However, sequence elements within their extracellular domain, such as signal sequence or N-glycosylation motifs, may result in differential regulation of biosynthetic processing and trafficking and in alterations to receptor function. We show that (i) BMPR1A and the ubiquitous isoform of BMPR1B differed in mode of translocation into the endoplasmic reticulum; and (ii) BMPR1A was N-glycosylated while BMPR1B was not, resulting in greater efficiency of processing and plasma membrane expression of BMPR1A. We further demonstrated the importance of BMPR1A expression and glycosylation in ES-2 ovarian cancer cells, where (i) CRISPR/Cas9-mediated knockout of BMPR1A abrogated BMP2-induced Smad1/5/8 phosphorylation and reduced proliferation of ES-2 cells and (ii) inhibition of N-glycosylation by site-directed mutagenesis, or by tunicamycin or 2-deoxy-D-glucose treatments, reduced biosynthetic processing and plasma membrane expression of BMPR1A and BMP2-induced Smad1/5/8 phosphorylation.

Unsuspected osteochondroma-like outgrowths in the cranial base of Hereditary Multiple Exostoses patients and modeling and treatment with a BMP antagonist in mice

Hereditary Multiple Exostoses (HME) is a rare pediatric disorder caused by loss-of-function mutations in the genes encoding the heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. HME is characterized by formation of cartilaginous outgrowths-called osteochondromas- next to the growth plates of many axial and appendicular skeletal elements. Surprisingly, it is not known whether such tumors also form in endochondral elements of the craniofacial skeleton. Here, we carried out a retrospective analysis of cervical spine MRI and CT scans from 50 consecutive HME patients that included cranial skeletal images. Interestingly, nearly half of the patients displayed moderate defects or osteochondroma-like outgrowths in the cranial base and specifically in the clivus. In good correlation, osteochondromas developed in the cranial base of mutant Ext1f/f;Col2-CreER or Ext1f/f;Aggrecan-CreER mouse models of HME along the synchondrosis growth plates. Osteochondroma formation was preceded by phenotypic alteration of cells at the chondro-perichondrial boundary and was accompanied by ectopic expression of major cartilage matrix genes -collagen 2 and collagen X- within the growing ectopic masses. Because chondrogenesis requires bone morphogenetic protein (BMP) signaling, we asked whether osteochondroma formation could be blocked by a BMP signaling antagonist. Systemic administration with LDN-193189 effectively inhibited osteochondroma growth in conditional Ext1-mutant mice. In vitro studies with mouse embryo chondrogenic cells clarified the mechanisms of LDN-193189 action that turned out to include decreases in canonical BMP signaling pSMAD1/5/8 effectors but interestingly, concurrent increases in such anti-chondrogenic mechanisms as pERK1/2 and Chordin, Fgf9 and Fgf18 expression. Our study is the first to reveal that the cranial base can be affected in patients with HME and that osteochondroma formation is amenable to therapeutic drug intervention.

Zebrafish small molecule screens: Taking the phenotypic plunge

Target based chemical screens are a mainstay of modern drug discovery, but the effectiveness of this reductionist approach is being questioned in light of declines in pharmaceutical R & D efficiency. In recent years, phenotypic screens have gained increasing acceptance as a complementary/alternative approach to early drug discovery. We discuss the various model organisms used in phenotypic screens, with particular focus on zebrafish, which has emerged as a leading model of in vivo phenotypic screens. Additionally, we anticipate therapeutic opportunities, particularly in orphan disease space, in the context of rapid advances in human Mendelian genetics, electronic health record (EHR)-enabled genome–phenome associations, and genome editing.

Inhibitors of the bone morphogenetic protein (BMP) signaling pathway: a patent review (2008-2015)

INTRODUCTION

The bone morphogenetic protein (BMP) is a critical signaling pathway and plays a diverse role in embryonic pattern formation and is implicated in a variety of disease processes, including anemia, bone formation, atherosclerosis, skin diseases, and cancers, among others. Areas covered: This review covers small molecule inhibitors/antagonists of BMP in patent applications between 2008 - 2015, along with brief synopses of the disclosed inhibitors in the primary literature. Expert opinion: The development of potent and selective BMP inhibitors is ongoing with most of the work centered around improving the selectivity and pharmacokinetic profile. Early work was for the treatment of the rare and neglected disease, fibrodysplasia ossificans progressiva (FOP). Recently, however, there has been increased interest in their use in a number of other diseases such as cancer, atherosclerosis, and anemia of chronic disease, to name a few. Although the primary participants in the early work were from academic laboratories, recently a significant surge from the pharmaceutical industry has elevated the interest in the development of BMP inhibitors for a wide-range of therapeutic indications. Due to this, expect a number of new approaches such as repurposing of other kinase inhibitors to be brought into clinical trials in the near future.

Dorsomorphin homologue 1, a highly selective small-molecule bone morphogenetic protein inhibitor, suppresses medial artery calcification

BACKGROUND

Medial artery calcification develops in diabetes, chronic kidney disease, and as part of the aging process. It is associated with increased morbidity and mortality in vascular patients. Bone morphogenetic proteins (BMPs) have previously been implicated in the initiation and progression of vascular calcification. We thus evaluated whether dorsomorphin homologue 1 (DMH1), a highly selective BMP inhibitor, could attenuate vascular calcification in vitro and in an organ culture model of medial calcification.

METHODS

Confluent human aortic smooth muscle cells (SMCs) were cultured in calcification medium containing 3.0 mM inorganic phosphate (Pi) for 7 days with or without DMH1. Medial calcification was assessed using an aortic organ culture model. Calcification was visualized by alizarin red S staining, and calcium concentration was assessed by an o-cresolphthalein complexone calcium assay. Osteogenic cell and vascular SMC markers were determined by Western blot, quantitative reverse transcription polymerase chain reaction, and immunohistochemical staining.

RESULTS

DMH1 reduced Pi-induced calcium deposition in human SMCs. It also antagonized human recombinant BMP2-induced calcium accumulation. Western blot further revealed that DMH1 was able to block Pi-mediated upregulation of the osteoblast markers osterix and alkaline phosphatase and downregulation of the SMC markers smooth muscle myosin heavy chain and SM22α as well as p-Smad1/5/8, suggesting that DMH1 may regulate SMC osteogenic differentiation through the BMP/Smad1/5/8 signaling pathway. Finally, using an ex vivo aortic ring organ culture model, we observed that DMH1 reduces Pi-induced aortic medial calcification.

CONCLUSIONS

The selective BMP inhibitor DMH1 can inhibit calcium accumulation in vascular SMCs and arterial segments exposed to elevated phosphate levels. Such small molecules may have clinical utility in reducing medial artery calcification in our population of vascular patients.

Targeting Stromal-Cancer Cell Crosstalk Networks in Ovarian Cancer Treatment

Ovarian cancer is a histologically, clinically, and molecularly diverse disease with a five-year survival rate of less than 30%. It has been estimated that approximately 21,980 new cases of epithelial ovarian cancer will be diagnosed and 14,270 deaths will occur in the United States in 2015, making it the most lethal gynecologic malignancy. Ovarian tumor tissue is composed of cancer cells and a collection of different stromal cells. There is increasing evidence that demonstrates that stromal involvement is important in ovarian cancer pathogenesis. Therefore, stroma-specific signaling pathways, stroma-derived factors, and genetic changes in the tumor stroma present unique opportunities for improving the diagnosis and treatment of ovarian cancer. Cancer-associated fibroblasts (CAFs) are one of the major components of the tumor stroma that have demonstrated supportive roles in tumor progression. In this review, we highlight various types of signaling crosstalk between ovarian cancer cells and stromal cells, particularly with CAFs. In addition to evaluating the importance of signaling crosstalk in ovarian cancer progression, we discuss approaches that can be used to target tumor-promoting signaling crosstalk and how these approaches can be translated into potential ovarian cancer treatment.

Mechanisms of action of bone morphogenetic proteins in cancer

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

Matters of context guide future research in TGFβ superfamily signaling

The highly conserved wiring of the SMAD-dependent transforming growth factor β (TGFβ) superfamily signaling pathway has been mapped over the last 20 years after molecular discovery of its component parts. Numerous alternative TGFβ-activated signaling pathways that elicit SMAD-independent biological responses also exist. However, the molecular mechanisms responsible for the renowned context dependency of TGFβ signaling output remains an active and often confounding area of research, providing a prototype relevant to regulation of other signaling pathways. Highlighting discoveries presented at the 9th FASEB meeting, The TGFβ Superfamily: Signaling in Development and Disease (July 12-17th 2015 in Snowmass, Colorado), this Review outlines research into the rich contextual nature of TGFβ signaling output and offers clues for therapeutic advances.