Schwannoma is a benign tumor that arises from the sheath of myelinated nerve fibers and may occur in any part of the body. Osteogenesis in schwannoma is extremely rare and, to date, new bone formation in sinonasal schwannoma has not yet been reported. Here, we describe the first reported case of sinonasal schwannoma with new bone formation. The tumor was successfully treated by endoscopic sinus surgery, and the patient showed no evidence of recurrence 24 months postoperatively. Immunohistochemically, the tumor expressed bone morphogenic protein 4, indicating a possible role of this protein in the new bone formation in schwannomas.
Previous reports suggest the application of exogenous BMPs can accelerate bone formation during distraction osteogenesis (DO). However, there are drawbacks associated with the use of exogenous BMPs. A possible alternative to the use of exogenous BMPs is to upregulate the expression of endogenous BMPs. Since DO results in spontaneously generated de novo bone formation in a uniform radiographic, histological, and biomechanical temporal sequence, a genetically engineered model lacking endogenous BMP2 should have measurable deficits in bone formation at different time points. We performed DO on BMP2 fl/+ and BMP2 fl/+ cre mice using a miniature Ilizarov fixator. Distracted samples were collected at various time points and analyzed using Real Time-quantitative PCR, μCT, radiology, immunohistochemistry, histology, and biomechanical testing. Immunohistochemical studies of 34-day heterozygous samples showed reduced expression of BMP2, BMP7, BMPR1a, ACTR1, and ACTR2b. μCT analysis of 51-day heterozygous samples revealed a decrease in trabecular number and increase in trabecular separation. Biomechanical testing of 51-day heterozygous samples revealed decreased stiffness and increased ultimate displacement. Radiological analysis showed the heterozygotes contained a decreased bone fill score at 17, 34, and 51 days. These data suggest endogenous BMPs are important for bone healing and manipulating endogenous BMPs may help accelerate bone consolidation during DO.
Ectopic expression of recombinant human bone morphogenetic protein 2 (rhBMP2) induces osteogenesis, while ectopic expression of rhBMP12 and rhBMP13 induces the formation of tendon-like tissue. Despite their different in vivo activities, all three ligands bound to the type I bone morphogenic protein receptors (BMPRs), activin receptor-like kinase (ALK)-3 and ALK6, and to the type II BMPRs, activin receptor type-2A, activin receptor type-2B, and BMPR2, with similar affinities. Treatment of C3H10T1/2 cells with rhBMP2 activated SMAD signaling and induced expression of osteoblast markers including osteocalcin mRNA (Ocn). In contrast, treatment with rhBMP12 or rhBMP13 resulted in a dose-dependent induction of a tendon-specific gene (Thbs4) expression with no detectable activation of SMAD 1, 5, and 8. Differential regulation of Thbs4 and Ocn has potential utility as an in vitro biomarker for induction of tenogenic signaling. Such an assay also permits the ability to distinguish between the activities of different BMPs and may prove useful in studies on the molecular mechanisms of BMP tenogenic activity.
Bone morphogenetic proteins; thrombospondin 4; tendon markers
We have recently shown that human recombinant BMP-6 (rhBMP-6), given systematically, can restore bone in animal models of osteoporosis. To further elucidate the underlying mechanisms of new bone formation following systemic application of BMPs, we conducted gene expression profiling experiments using bone samples of oophrectomised mice treated with BMP-6. Gene set enrichment analysis revealed enrichment of insulin-like growth factor-I and epidermal growth factor related pathways in animals treated with BMP-6. Significant upregulation of IGF-I and EGF expression in bones of BMP-6 treated mice was confirmed by quantitative PCR. To develop an in vitro model for evaluation of the effects of BMP-6 on cells of human origin, we cultured primary human osteoblasts. Treatment with rhBMP-6 accelerated cell differentiation as indicated by the formation of mineralised nodules by day 18 of culture versus 28–30 days in vehicle treated cultures. In addition, alkaline phosphatase gene expression and activity were dramatically increased upon BMP-6 treatment. Expression of IGF-I and EGF was upregulated in human osteoblast cells treated with BMP-6. These results collectively indicate that BMP-6 exerts its osteoinductive effect, at least in part, through IGF-I and EGF pathways, which can be observed both in a murine model of osteopenia and in human osteoblasts.
Sinonasal inverted papilloma (IP) is a primary benign lesion with a tendency for local recurrence. Malignant transformation may develop in up to 15% of cases. Fascin (Fascin 1) is an actin cross-link binding protein required for the formation of actin-based cell-surface protrusions and cell motility. Fascin up-regulation in lung, gastric, breast and hepatobiliary carcinomas correlates with aggressiveness and decreased survival. Here we evaluate immunohistochemical expression of fascin in 47 sinonasal IPs from 34 patients. Fascin over-expression is significantly more common in sinonasal IP with high-grade dysplasia than in those with no dysplastic or low-grade dysplastic epithelium (P = 0.0001). No significant change in fascin expression is seen with recurrence. Over expression of fascin in high-grade dysplastic epithelium in IP may be associated with tumor progression and malignant transformation.
Fascin; Sinonasal inverted papilloma; Dysplasia; Malignant transformation; Immunohistochemistry
Bone is unique of all the tissues in the vertebrate organism. When injured, it heals by formation of new bone. Bone morphogenetic proteins (BMPs) are powerful inductors of the osteogenic activity during the embryologic bone formation phase and in cases of bone healing. They have proliferative effects on different cellular types, showing chemotactic properties and are able to induce mesenchymal cells differentiation into osteoblastic and chondroblastic line cells. Both primary cells and cell lines have been shown to respond to BMPs. Further the ability of embryonic cells to respond to BMPs by differentiating into cartilage and bone cells suggests that they are involved in the development of embryonic skeletal system. In addition, these proteins can also promote the angiogenesis, regulate the activity of some growth factors, and affect the production of these growth factors, which is helpful for the osteogenesis. BMPs have been considered as the most potent growth factors that can promote the bone regeneration. Thus, the aim of this review is to emphasize on the unique nature of the BMP molecules regarding their structure, classification, signaling mechanism, etc., as BMPs are the only molecules which show such deviation from the normal order, type. This will further help in understanding the role of BMPs and their potential advances which are necessary to facilitate the process of regeneration in periodontics.
Bone; growth factors; healing; repair
The aim of this study was to determine whether biphasic calcium phosphate (BCP) bone substitute with two different concentrations of Escherichia coli-expressed recombinant human bone morphogenetic protein 2 (ErhBMP-2) enhances new bone formation in a standardized rabbit sinus model and to evaluate the concentration-dependent effect of ErhBMP-2.
Standardized, 6-mm diameter defects were made bilaterally on the maxillary sinus of 20 male New Zealand white rabbits. Following removal of the circular bony windows and reflection of the sinus membrane, BCP bone substitute without coating (control group) was applied into one defect and BCP bone substitute coated with ErhBMP-2 (experimental group) was applied into the other defect for each rabbit. The experimental group was divided into 2 subgroups according to the concentration of ErhBMP-2 (0.05 and 0.5 mg/mL). The animals were allowed to heal for either 4 or 8 weeks and sections of the augmented sinus and surrounding bone were analyzed by microcomputed tomography and histologically.
Histologic analysis revealed signs of new bone formation in both the control and experimental groups with a statistically significant increase in bone formation in experimental group 1 (0.05 mg/mL ErhBMP-2 coating) after a 4-week healing period. However, no statistically significant difference was found between experimental group 1 and experimental group 2 (0.5 mg/mL ErhBMP-2 coating) in osteoinductive potential (P<0.05).
ErhBMP-2 administered using a BCP matrix significantly enhanced osteoinductive potential in a standardized rabbit sinus model. A concentration-dependent response was not found in the present study.
Bone morphogenetic protein 2; Bone regeneration; Bone substitute; Maxillary sinus; Rabbits
Sonication-induced silk hydrogels were previously prepared as an injectable bone replacement biomaterial, with a need to improve osteogenic features. Vascular endothelial growth factor (VEGF165) and bone morphogenic protein-2 (BMP-2) are key regulators of angiogenesis and osteogenesis, respectively, during bone regeneration. Therefore, the present study aimed at evaluating in situ forming silk hydrogels as a vehicle to encapsulate dual factors for rabbit maxillary sinus floor augmentation. Sonication-induced silk hydrogels were prepared in vitro and the slow release of VEGF165 and BMP-2 from these silk gels was evaluated by ELISA. For in vivo studies for each time point (4 and 12 weeks), 24 sinus floors elevation surgeries were made bilaterally in 12 rabbits for the following four treatment groups: silk gel (group Silk gel), silk gel/VEGF165 (group VEGF), silk gel/BMP-2 (group BMP-2), silk gel/VEGF165/BMP-2 (group V+B) (n=6 per group). Sequential florescent labeling and radiographic observations were used to record new bone formation and mineralization, along with histological and histomorphometric analysis. At week 4, VEGF165 promoted more tissue infiltration into the gel and accelerated the degradation of the gel material. At this time point, the bone area in group V+B was significantly larger than those in the other three groups. At week 12, elevated sinus floor heights of groups BMP-2 and V+B were larger than those of the Silk gel and VEGF groups, and the V+B group had the largest new bone area among all groups. In addition, a larger blood vessel area formed in the remaining gel areas in groups VEGF and V+B. In conclusion, VEGF165 and BMP-2 released from injectable and biodegradable silk gels promoted angiogenesis and new bone formation, with the two factors demonstrating an additive effect on bone regeneration. These results indicate that silk hydrogels can be used as an injectable vehicle to deliver multiple growth factors in a minimally invasive approach to regenerate irregular bony cavities.
The study purpose was to detect the value of magnetic resonance imaging (MRI) compared to computed tomography (CT) and different imaging modalities as conventional radiology in evaluation of sinonasal neoplasms diagnosed by Histopathology.
Thirty patients (16 males and 14 females) were complaining of symptoms related to sinonasal tract. After thorough clinical and local examination, the patients were subjected to the following: conventional radiography, CT, MRI, and histopathological examination.
The nasal cavity was the most commonly involved site with sinonasal malignancies followed by the maxillary sinuses. The least commonly affected site was the frontal sinuses. Benign sinonasal tumors were present in 14 cases. The most common benign lesion was juvenile nasopharyngeal angiofibroma (6 cases), followed by inverted papilloma (3 cases). While malignant sinonasal tumors were present in 16 cases, squamous cell carcinoma was present in 5 cases, and undifferentiated carcinoma, in 3 cases. Lymphoepithelioma and non-Hodgkin lymphomas were present in 2 cases each, while adenocarcinoma, chondrosarcoma, adenoid cystic carcinoma, and rhabdomyosarcoma were present in 1 case each.
MRI with its superior soft tissue contrast and multiplanar capability is superior to CT in pretreatment evaluation of primary malignant tumors of sinonasal cavity.
magnetic resonance imaging; computed tomography; sinonasal tumor
Induction of new bone formation is frequently seen in the bone lesions from prostate cancer (PCa). However, whether osteogenesis is necessary for prostate tumor growth in bone is unknown. Recently, two xenografts, MDA-PCa-118b and MDA-PCa-133, were generated from PCa bone metastases. When implanted subcutaneously in SCID mice, MDA-PCa-118b induced strong ectopic bone formation while MDA-PCa-133 did not. To identify the factors that are involved in bone formation, we compared the expression of secreted factors (“secretome”) from MDA-PCa-118b and MDA-PCa-133 by cytokine array. We found that the osteogenic MDA-PCa-118b xenograft expressed higher levels of BMP-4 and several cytokines including IL-8, Gro, and CCL2. We demonstrated that BMP-4 secreted from MDA-PCa-118b contributed to about a third of the osteogenic differentiation seen in MDA-PCa-118b tumors. The conditioned media from MDA-PCa-118b induced a higher level of osteoblast differentiation, which was significantly reduced by treating with BMP-4 neutralizing antibody or the small molecule BMP receptor 1 inhibitor LDN-193189. BMP-4 did not elicit an autocrine effect on MDA-PCa-118b, which expressed low to undetectable levels of BMP receptors. Treatment of SCID mice bearing MDA-PCa-118b tumors with LDN-193189 significantly reduced tumor growth. Thus, these studies support a role of BMP4-mediated osteogenesis in the progression of PCa in bone.
PCa; bone metastasis; chemokines; cytokines; osteoblast
Mesenchymal progenitor stem cells (MPCs) are a group of bone marrow stromal progenitor cells processing osteogenic, chondrogenic, adipogenic and myogenic lineages differentiations. Previous studies have demonstrated that bone morphogeneic protein 9(BMP9) is one of the most osteogenic BMPs both in vitro and in vivo, however, the underlying molecular mechanism of osteogenesis induced by BMP9 is needed to be deep explored. Here, we used the recombinant adenoviruses assay to introduce BMP9 into C3H10T1/2 mesenchymal stem cells to elucidate the role of CXCL12/CXCR4 signal axis during BMP9-incuced osteogenic differentiation. The results showed that CXCL12 and CXCR4 expressions were down-regulated at the stage of BMP9-induced osteogenic differentiation, in a dose- and time-dependent. Pretreatment of C3H10T1/2 cells with CXCL12/CXCR4 could significantly affect the early and mid osteogenic markers alkaline phosphatase (ALP), osteocalcin (OCN), the transcription factors of Runx2, Osx, Plzf and Dlx5 expression, through activating the Smad, MAPK signaling pathway. Addition of exogenous CXCL12 did not affect the changes of the late osteogenic marker calcium deposition. Thus, our findings suggest a co-requirement of the CXCL12/CXCR4 signal axis in BMP9-induced the early- and mid-process of osteogenic differentiation of MSCs.
CXCL 12; CXCR4; Bone Morphogenetic Protein 9; Mesenchymal Stem Cells; Osteogenic Differentiation.
Sinonasal inverted papilloma (IP) is a rare, usually benign tumor arising from the respiratory mucosa of the sinonasal tract. Surgical resection is the treatment of choice. In histologically overt benign IPs (i.e. without associated malignancy) irradiation was employed only anecdotally. The patient with gross residual of benign IP after up-front surgery that was subsequently treated with irradiation is presented and the literature reports on the use of radiotherapy (RT) in this tumor type are reviewed.
After the surgical treatment the residuum in the region of the sphenoid and adjacent cavernous sinus was irradiated to 54 Gy in 1.8 Gy daily fractions. No recurrence or deterioration of olfaction, hearing or vision was observed 2.6 years post-RT.
Review of the literature
In the literature, six reports were identified with 16 patients describing necessary details on RT and outcome. Twelve of 14 cases (our case included) with gross or subtotal tumor resection and postoperative RT were locally controlled. The lowest and the median irradiation doses were 47.15 Gy and 56.5 Gy, respectively, and the follow-up period ranged between 0.5–20.5 years (median 7.8 years).
RT is safe and valuable treatment option in histologically overt benign IPs. It is indicated when the risk of tumor recurrence after surgery is increased and in inoperable tumors.
inverted papilloma; local control; radiotherapy; surgery
Using a molecular genetic approach, we try to confirm the molecular alterations of inverted papilloma and clarify its status as a putative precursor lesion of sinonasal squamous cell carcinoma. To better understand its genetics, we investigated the immunohistochemical protein expression patterns of cell-cycle-regulators p53, p63, p21, p27 and proliferation marker Ki-67 in 22 inverted papilloma and 9 squamous cell carcinoma of the sinonasal tract. Significantly elevated levels of p53 and p63 in squamous cell carcinoma of sinonasal tract compared with inverted papilloma were revealed. Ki-67-stained neoplastic cell nuclei were found in a significantly higher percentage of squamous cell carcinoma of sinonasal tract than in inverted papilloma, whereas no variation of p21 and p27 expression was identified. This work first examined the immunohistochemical overexpression of p63 in sinonasal inverted papilloma and squamous cell carcinoma. In conclusion, this is a first study shedding light on the expression of p63 in tumors of paranasal sinuses.
Inverted papilloma; p63; p53; Sinonasal squamous cell carcinoma; p21; Cell cycle regulators; MIB-1
Bone morphogenetic protein (BMP) 1 is a vertebrate metalloproteinase of the astacin family. BMP1 plays a key role in regulating the formation of the extracellular matrix (ECM), particularly by processing the C-propeptide of fibrillar procollagens. BMP1 also promotes BMP signaling by releasing BMP signaling molecules from complexes with the BMP-antagonist chordin. As a result of BMP1′s dual role in both ECM formation and BMP signaling, we hypothesized that BMP1 could play a role in ovarian physiology. Using the sheep ovary as a model system, we showed that BMP1 was expressed in the ovary throughout early fetal stages to adulthood. Furthermore, in adult ovaries, BMP1 was expressed along with chordin, BMP4, and twisted gastrulation, which together form an extracellular regulatory complex for BMP signaling. Within ovine ovaries, immunohistochemical localization demonstrated that BMP1 was present in granulosa cells at all stages of follicular development, from primordial to large antral follicles, and that the levels of BMP1 were not affected by the final follicle selection mechanism. In cultured granulosa cells, BMP1 expression was not affected by gonadotropins, but BMP4 and activin A had opposing effects on the levels of BMP1 mRNA. BMP1 appeared to be secreted into the follicular fluid of antral follicles, where it is able to exert procollagen C-proteinase and chordinase activities. Interestingly, BMP1 activity in follicular fluid decreased with follicular growth.
Enzymatically active bone morphogenetic protein 1 (BMP1) is produced by granulosa cells and is present in the follicular fluid of ovine ovarian follicles.
BMP1; follicle; follicular development; granulosa cells; ovary
Members of the bone morphogenetic protein (BMP) family have diverse physiological roles. For instance, BMP-2 stimulates osteogenesis, while BMP-12 induces the formation of tendon/ligament-like tissues. Here, we designed a study to determine whether BMP-12 has bone and/or cartilage regeneration abilities similar to those of BMP-2. We implanted plasmid vectors encoding either BMP-2 or BMP-12 in rats with femur defects, and monitored the bone healing process for 8-weeks. The BMP-12 transgene induced prominent fibrogenesis by 2 weeks, with bone substitution occurring by 8 weeks. BMP-2, however, was associated predominantly with osteogenesis throughout the 8 week period. Thus, we conclude that BMP-12 does not function similarly to BMP-2 during bone healing. Further work is needed to better understand the mechanisms by which it stimulates bony growths to replace the connective tissues formed during the first stages of bone healing.
Inverted papilloma (IP) is a benign tumor of the nasal cavity and paranasal sinuses that is unilateral in most cases. Bilateral IP, involving both sides of the nasal cavity and sinuses, is extremely rare. This paper describes a large IP that filled in both sides of the nasal cavity and sinuses, mimicking association with malignancy. The tumor was successfully treated by bilateral endoscopic medial maxillectomy (EMM). The patient is without evidence of the disease 24 months after surgery. If preoperative diagnosis does not confirm the association with malignancy in IP, endoscopic sinus surgery (ESS) should be selected, and ESS, including EMM, is a good first choice of the treatment for IP.
The Matrix Metalloproteinase (MMP), Fibroblast Growth Factor (FGF) and Bone Morphogenetic Protein (BMP) families regulate tissue remodeling in many normal and pathophysiologic processes. We hypothesize that induction of chronic sinonasal inflammation will be associated with changes in regulation of these tissue remodeling cytokines.
Balb/c mice aged 8–12 weeks were sensitized and treated with intranasal Aspergillus fumigatis (AF) three times per week for 1 week, 3 weeks, 2 months and 3 months (n=8 each time point). Sinonasal tissues were evaluated for changes in MMP, FGF and BMP regulation using standard RT-PCR techniques. Additional snouts were processed for histology and immunohistochemistry. Untreated mouse snouts of identical age were used as controls.
Significant upregulation of MMP8 was observed at 2 months, and MMP1a, MMP7, MMP8 and MMP12 were all significantly upregulated at 3 months. FGF3 was significantly upregulated at 3 weeks and 3 months, and FGF5, FGF6 and FGF8 were all significantly upregulated at 3 months. BMP8b and BMP9 were significantly upregulated at 3 months. Histologic analysis revealed mucosal, stromal and mucin gland hypertrophy, increased mucin production, and metaplasia with loss of cilia. Antibody staining was strongly positive in the AF treated group.
Induction of CRS is associated with time-dependent changes in tissue remodeling cytokine expression occurring in conjuction with inflammatory tissue changes. Antibody staining for upregulated cytokines suggests local production within the sinonasal mucosa. Further study is required to better understand the association between BMP, FGF and MMP regulation and tissue remodeling changes resulting from chronic inflammation.
Tissue remodeling; chronic rhinosinusitis; murine model; MMP; BMP; FGF
The purpose of this study was to explore the effect of heparin on bone morphogenetic protein 6 (BMP6) osteogenic activity.
Western blot analysis was used to confirm the binding of BMP6 to heparin and to observe its effect on BMP6 signaling in C2C12-BRE-Luc myoblasts. Real-time RT-PCR was performed for the expression analysis of alkaline phosphatase (ALP) and osteocalcin (OC) in C2C12 myoblasts treated with BMP6 and heparin for 72 hours. Rat ectopic bone formation assay was performed to explore the effect of heparin on BMP6 osteogenic activity. Two weeks following implantation the implants were analysed morphologically and histologically. A mouse osteoporotic model was used to test the ability of BMP6 to improve the bone quality in vivo in the presence of heparin, followed by DEXA and μCT analyses. Blood coagulation was tested in rats previously treated with BMP6.
BMP6 specifically bound to heparin and induced Smad1/5/8 phosphorylation which was inhibited by heparin. After 48 and 72 hours of treatment, heparin inhibited BMP6-induced ALP and OC expression in C2C12 cells. Heparin dose dependently inhibited BMP6-induced new bone and cartilage formation in the rat ectopic bone formation assay, while in osteoporotic mice heparin inhibited the BMP6 potential to improve the bone quality as evidenced by decreased bone mineral density and trabecular bone parameters. Interestingly, BMP6 prevented the effect of heparin on the blood coagulation parameters.
The interaction of BMP6 with heparin might contribute to the heparin-induced osteoporosis and blood coagulation.
We describe a case of benign inverted papilloma with intracranial extension treated with endoscopic resection combined with craniotomy. Intracranial involvement of inverted papilloma, in the absence of malignancy, is uncommon. We present an analysis of the literature identifying the characteristics and outcomes of benign intracranial inverted papilloma. PubMed database was searched using keywords intracranial, inverted or inverting, and papilloma. There are 17 reports of benign inverted papilloma with intracranial extension reported with a mean age of 49.2 years (range, 23 to 92 years), a female predominance, 22% of cases with an associated mucocele, and 60% recurrent disease. The most common sites of invasion are the frontal sinus or cribriform plate. The prognosis for benign intracranial inverted papilloma is dependent on the presence of dural invasion and the achievement of total resection. There are no reported recurrences after craniofacial resection with a mean follow-up of 7.9 years. Adjuvant radiation therapy has demonstrated benefit in cases of residual disease after resection. We expect that endoscopic resection, the standard treatment for sinonasal inverted papilloma, will be increasingly used in the presence of intracranial extension.
Intracranial; inverted; inverting; Schneiderian; papilloma
The creation of entirely synthetically derived bone substitute materials which are as effective as autologous bone grafts is desirable. Osteogenesis involves the concerted action of several proteins within a signaling cascade. Hedgehog proteins act upstream of this cascade, inducing the expression of various bone morphogenetic proteins (BMPs) and promoting physiological bone healing. Therefore, the hypothesis that hedgehog signaling in bone defects improves bone healing more than BMP signaling alone was tested. Recombinant N-terminal sonic hedgehog protein (N-SHh), BMP-2 or a combination of the two was added to β-tricalcium phosphate (β-TCP) and 5-mm femoral midshaft defects in nude rats were filled with these composites. The defects were stabilized with mini-plates. After eight weeks, the animals were sacrificed and the femora were explanted. The radiological evaluation was followed by a three-point bending test and histological examination. BMP-2/β-TCP composites showed a trend of increased stiffness compared with the controls (β-TCP without protein). N-SHh/β-TCP composites had lower stiffness compared with the control group and the N-SHh/BMP-2/β-TCP composites also had lower average stiffness compared with the controls (all not significant). Histomorphometry, however, revealed abundant cartilage and bone core formation in the N-SHh-composite groups. The sum of the new cartilage and bone was highest in the combination group N-SHh/BMP-2 (not significant). The addition of N-SHh to bone substitute materials appears to delay bone healing at the applied concentration and observation time but also showed a trend for higher amounts of ossifying cartilage.
bone substitute material; tricalcium phosphate; sonic hedgehog; bone morphogenetic protein-2; rat femur defect; three point bending test
Skeletal muscle-derived stem cells (MDSCs) can undergo osteogenesis when treated with bone morphogenetic proteins (BMPs), making them a potential cell source for bone tissue engineering. The signaling pathways that regulate BMP4-induced osteogenesis in MDSCs are not well understood, although they may provide a means to better regulate differentiation during bone regeneration. The objective of this study was to characterize the signaling pathways involved in the BMP4-induced osteogenesis of MDSCs. Cells were treated with BMP4 and specific inhibitors to the extracellular signal-regulated kinases 1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and phosphatidyl inositol 3-kinase (PI3K) pathways (PD98059, SB203580, and Ly294002, respectively). Cellular proliferation, expression of osteoblast-related genes, alkaline phosphatase (ALP) activity, and tissue mineralization were measured to determine the role of each pathway in the osteogenic differentiation of MDSCs. Inhibition of the ERK1/2 pathway increased ALP activity and mineralization, whereas inhibition of the p38 MAPK pathway decreased osteogenesis, suggesting opposing roles of these pathways in the BMP4-induced osteogenesis of MDSCs. Inhibition of the PI3K pathway significantly increased mineralization by MDSCs. These findings highlight the involvement of the ERK1/2, p38 MAPK, and PI3K pathways in opposing capacities in MDSC differentiation and warrant further investigation, as it may identify novel therapeutic targets for the development of stem cell-based therapies for bone tissue engineering.
Bone morphogenetic proteins (BMPs) are highly conserved morphogens that are essential for normal development. BMP-2 is highly expressed in the majority of non-small cell lung carcinomas (NSCLC) but not in normal lung tissue or benign lung tumors. The effects of the BMP signaling cascade on the growth and survival of cancer cells is poorly understood. We show that BMP signaling is basally active in lung cancer cell lines, which can be effectively inhibited with selective antagonists of the BMP type I receptors. Lung cancer cell lines express alk2, alk3, and alk6 and inhibition of a single BMP receptor was not sufficient to decrease signaling. Inhibition of more than one type I receptor was required to decrease BMP signaling in lung cancer cell lines. BMP receptor antagonists and silencing of BMP type I receptors with siRNA induced cell death, inhibited cell growth, and caused a significant decrease in the expression of inhibitor of differentiation (Id1, Id2, and Id3) family members, which are known to regulate cell growth and survival in many types of cancers. BMP receptor antagonists also decreased clonogenic cell growth. Knockdown of Id3 significantly decreased cell growth and induced cell death of lung cancer cells. H1299 cells stably overexpressing Id3 were resistant to growth suppression and induction of cell death induced by the BMP antagonist DMH2. These studies suggest that BMP signaling promotes cell growth and survival of lung cancer cells, which is mediated through its regulation of Id family members. Selective antagonists of the BMP type I receptors represents a potential means to pharmacologically treat NSCLC and other carcinomas with an activated BMP signaling cascade.
Sinonasal papillomas are benign epithelial neoplasms arising from Schneiderian mucosa. The three subtypes, exophytic, oncocytic, and inverted (inverted papilloma [IP]), should be distinguished from one another histopathologically. This study (1) highlights the histopathological and clinical differences between the Schneiderian papilloma subtypes and (2) identifies clinical features that potentially predict papilloma subtypes.
A retrospective review was performed of patients with Schneiderian papillomas over an 11-year period.
Seventy patients with sinonasal papillomas who underwent sinus surgery were identified. There were 50 (71%) male and 20 (29%) female subjects diagnosed at an average age of 53 years (range, 13–80 years). Exophytic (n = 25), oncocytic (n = 9), and IP (n = 37) were identified. IP was associated with transformation into squamous cell carcinoma in three (8%) cases and dysplasia in three (8%) cases. Neither oncocytic nor exophytic subtypes were associated with dysplasia or malignancy. On multivariate analysis of potential predictors of papilloma subtype, history of chronic rhinosinusitis (CRS) and location of papilloma were significantly associated with papilloma subtype. Using classification and regression tree model, papilloma subtypes can be predicted based on presence or absence of CRS and papilloma location with nominal 82.4% accuracy.
The inverted and exophytic type are the most common sinonasal papillomas, with the inverted type having an 8% rate of malignant transformation in this study. In contrast, the oncocytic type was not associated with dysplasia or malignancy in our series despite reports in the literature indicating malignant potential. History of CRS and papilloma location can provide clues to the histological subtype, which is important for surgical planning and patient counseling.
Cylindrical cell; exophytic; inverted; oncocytic; Schneiderian papillomas; sinonasal papillomas
The precise mechanism of heterotopic ossification caused by several types of tumours is largely unknown. However, recent studies have indicated that bone morphogenetic protein 2 (BMP2) is closely linked to the Wnt/β-catenin signaling pathway in this rare phenomenon of bone formation. We report a rare case of adrenal myelolipoma (ML) in a 27-year-old woman with heterotopic bone formation. Immunohistochemical findings showed BMP2 expression in the cytoplasm of tumour cells, as well as the matrix adjacent to newly developed bone tissue. In addition, β-catenin was prominent in the cytoplasm and nuclei of BMP2-positive tumour cells. To the best of our knowledge, this is the first report of adrenal ML showing heterotopic ossification with accelerated expression of both BMP2 and β-catenin. Our case findings indicate that BMP2 overexpression via aberrant canonical Wnt/β-catenin signaling may contribute to heterotopic bone formation occurring in adrenal ML.
Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily of growth factors. They are known for their roles in regulation of osteogenesis and developmental processes and, in recent years, evidence has accumulated of their crucial functions in tumor biology. BMP4 and BMP7, in particular, have been implicated in breast cancer. However, little is known about BMP target genes in the context of tumor. We explored the effects of BMP4 and BMP7 treatment on global gene transcription in seven breast cancer cell lines during a 6-point time series, using a whole-genome oligo microarray. Data analysis included hierarchical clustering of differentially expressed genes, gene ontology enrichment analyses and model based clustering of temporal data.
Both ligands had a strong effect on gene expression, although the response to BMP4 treatment was more pronounced. The cellular functions most strongly affected by BMP signaling were regulation of transcription and development. The observed transcriptional response, as well as its functional outcome, followed a temporal sequence, with regulation of gene expression and signal transduction leading to changes in metabolism and cell proliferation. Hierarchical clustering revealed distinct differences in the response of individual cell lines to BMPs, but also highlighted a synexpression group of genes for both ligands. Interestingly, the majority of the genes within these synexpression groups were shared by the two ligands, probably representing the core molecular responses common to BMP4 and BMP7 signaling pathways.
All in all, we show that BMP signaling has a remarkable effect on gene transcription in breast cancer cells and that the functions affected follow a logical temporal pattern. Our results also uncover components of the common cellular transcriptional response to BMP4 and BMP7. Most importantly, this study provides a list of potential novel BMP target genes relevant in breast cancer.
bone morphogenetic protein; breast cancer; BMP4; BMP7; expression microarray