Bone morphogenetic protein-2/4 and bone morphogenetic protein receptor type IA expression in metastatic and nonmetastatic oral squamous cell carcinoma

BMP-2 and Noggin Immunoexpression in Ameloblastomas, Odontogenic Keratocysts, and Dentigerous Cysts

BMP-2 and Noggin are expressed in several tissues and participate in cell differentiation and proliferation during odontogenesis and tumor development. We evaluated the immunohistochemical expression of these proteins in ameloblastomas (AMs), odontogenic keratocysts (OKCs), and dentigerous cysts (DCs). The expression in AM (n.20), OKC (n.20), and DC (n.20) was evaluated by the percentage of positive cells and expression intensity, resulting in a total immunostaining score. Analysis of BMP-2 and Noggin revealed positivity in all cases. The Mann-Whitney test showed a statistically significant difference for Noggin between AM and DC and between OKC/DC. The mean DC scores were always higher than those of the other groups, regardless of the assessment method. Individual analysis of each lesion showed a positive and significant correlation between the percentage of cells positive for BMP-2 and Noggin in DC. We demonstrated the presence of BMP-2 and Noggin in AMs/OKCs/DCs. Marked expression of BMP-2 was observed in OKCs and AMs. There was also a positive correlation between BMP-2 and Noggin in DCs, suggesting a greater role of these markers in the bone formation and remodeling process since DCs are characterized by phases of bone quiescence and healing.

The Epstein-Barr Virus-Encoded EBNA1 Protein Activates the Bone Morphogenic Protein (BMP) Signalling Pathway to Promote Carcinoma Cell Migration

The Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) protein is expressed in all virus-associated malignancies, where it performs an essential role in the maintenance, replication and transcription of the EBV genome. In recent years, it has become apparent that EBNA1 can also influence cellular gene transcription. Here, we demonstrate that EBNA1 is able to stimulate the expression of the Transforming growth factor-beta (TGFβ) superfamily member, bone morphogenic protein 2 (BMP2), with consequential activation of the BMP signalling pathway in carcinoma cell lines. We show that BMP pathway activation is associated with an increase in the migratory capacity of carcinoma cells, an effect that can be ablated by the BMP antagonist, Noggin. Gene expression profiling of authentic EBV-positive nasopharyngeal carcinoma (NPC) tumours revealed the consistent presence of BMP ligands, established BMP pathway effectors and putative target genes, constituting a prominent BMP “signature” in this virus-associated cancer. Our findings show that EBNA1 is the major viral-encoded protein responsible for activating the BMP signalling pathway in carcinoma cells and supports a role for this pathway in promoting cell migration and possibly, metastatic spread.

Prognostic significance of bone morphogenetic protein 6 (BMP6) expression, clinical and pathological factors in clinically node-negative oral squamous cell carcinoma (OSCC)

Bone morphogenetic protein 6 (BMP6) has unique properties regarding structure and function in supporting bone formation during development and adult life. Despite its known role in various malignant tumors, the prognostic significance of BMP6 expression in oral squamous cell carcinoma (OSCC) remains unknown. The aim of the study was to investigate immunohistochemical expression of BMP6 in OSCC in correlation with clinical and pathological parameters, disease recurrence and survival. In addition, we investigated other parameters in order to identify prognosticators of neck metastases and final outcome. The study included 120 patients with clinically T1-3N0 OSCC who were primarily surgically treated between 2003 and 2008. There were 99 (82.5%) male and 21 (17.5%) female patients. The five-year disease-specific survival for the whole cohort was 79.7%. Tumors smaller than 2 cm in diameter showed higher incidence of strong BMP6 expression. No statistical correlation was observed between other clinico-pathological factors and BMP6 expression. Expression of BMP6 was not associated with disease recurrence and survival. BMP6 may not serve as prognosticator of final outcome or recurrence in clinically node-negative OSCC subjects. In multivariate analysis predictors of poorer survival were positive surgical margin, moderate tumor cell differentiation and pathological involvement of levels IV and/or V.

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.

Bone morphogenetic protein-2 and tumor growth: Diverse effects and possibilities for therapy

Concern regarding safety with respect to the clinical use of human bone morphogenetic protein-2 (BMP-2) has become an increasingly controversial topic. The role of BMP-2 in carcinogenesis is of particular concern. Although there have been many studies of this topic, the results have been contradictory and confusing. We conducted a systematic review of articles that are relevant to the relationship or effect of BMP-2 on all types of tumors and a total of 97 articles were included. Studies reported in these articles were classified into three major types: "expression studies", "in vitro studies", and "in vivo studies". An obvious pattern was that those works that hypothesize an inhibitory effect for BMP-2 most often examined only the proliferative properties of the tumor cells. This subset of studies also contained an extraordinary number of contradictory findings which made drawing a reliable general conclusion impossible. In general, we support a pro-tumorigenesis role for BMP-2 based on the data from these in vitro cell studies and in vivo animal studies, however, more clinical studies should be carried out to help make a firm conclusion.

Association Between BMP-2 and Carcinogenicity

STUDY DESIGN

Literature review.

OBJECTIVE

To evaluate the association between recombinant human bone morphogenetic protein-2 (rhBMP-2) and malignancy.

SUMMARY OF BACKGROUND DATA

The use of rhBMP-2 in spine surgery has been the topic of much debate as studies assessing the association between rhBMP-2 and malignancy have come to conflicting conclusions.

METHODS

A systematic review of the literature was performed using the PubMed-National Library of Medicine/National Institute of Health databases. Only non-clinical studies directly addressing BMP-2 and cancer were included. Articles were categorized by study type (animal, in vitro cell line/human/animal), primary malignancy, cancer attributes, and whether BMP-2 was pro-malignancy or not.

RESULTS

A total of 4,131 articles were reviewed. Of those, 515 articles made reference to both BMP-2 and cancer, 99 of which were found to directly examine the role of BMP-2 in cancer. Seventy-five studies were in vitro and 24 were animal studies. Forty-three studies concluded that BMP-2 enhanced cancer function, whereas 18 studies found that BMP-2 suppressed malignancy. Thirty-six studies did not examine whether BMP-2 enhanced or suppressed cancer function. Fifteen studies demonstrated BMP-2 dose dependence (9 enhancement, 6 suppression) and one study demonstrated no dose dependence. Nine studies demonstrated BMP-2 time dependence (6 enhancement, 3 suppression). However, no study demonstrated that BMP-2 caused cancer de novo.

CONCLUSION

Currently, conflicting data exist with regard to the effect of exogenous BMP-2 on cancer. The majority of studies addressed the role of BMP-2 in prostate (17%), breast (17%), and lung (15%) cancers. Most were in vitro studies (75%) and examined cancer invasiveness and metastatic potential (37%). Of 99 studies, there was no demonstration of BMP-2 causing cancer de novo. However, 43% of studies suggested that BMP-2 enhances tumor function, motivating more definitive research on the topic that also includes clinically meaningful dose- and time-dependence.

LEVEL OF EVIDENCE

2.

Different approaches for interpretation and reporting of immunohistochemistry analysis results in the bone tissue - a review

BACKGROUND

Immunohistochemistry (IHC) is a well-established, widely accepted method in both clinical and experimental parts of medical science. It allows receiving valuable information about any process in any tissue, and especially in bone. Each year the amount of data, received by IHC, grows in geometric progression. But the lack of standardization, especially on the post-analytical stage (interpreting and reporting of results), makes the comparison of the results of different studies impossible.

METHODS

Comprehensive PubMED literature search with a combination of search words "immunohistochemistry" and "scoring system" was performed and 773 articles describing IHC results were identified. After further manual analysis 120 articles were selected for detailed evaluation of used approaches.

RESULTS

Six major approaches to the interpretation and presentation of IHC analysis results were identified, analyzed and described.

CONCLUSIONS

The overview of the existing approaches in evaluation and interpretation of IHC data, which are provided in the article, can be used in bone tissue research and for either better understanding of existing scoring systems or developing a new one. Standard multiparametric, semiquantitative IHC scoring systems should simplify and clarify the process of interpretation and reporting of received data.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_221.

BMP-2 expression correlates with local failure in head and neck squamous cell carcinoma

OBJECTIVE

Preclinical data show that exogenous administration of recombinant human bone morphogenetic protein-2 (rhBMP-2) to human oral carcinoma cell lines increases pathogenicity using a nude mouse model. The objectives of this study are to (1) describe the characteristics of baseline protein expression of BMP-2 in head and neck squamous cell carcinomas (HNSCC) and (2) determine if BMP-2 expression level correlates with worse oncologic outcomes.

STUDY DESIGN

Retrospective analysis of previously harvested patient samples.

SETTING

Academic medical center.

SUBJECTS

In total, 149 patients with oral cavity, oropharynx, larynx, and hypopharynx HNSCC treated between January 1, 1997, and December 31, 2004.

METHODS

A tissue microarray of HNSCC was assembled and immunohistochemistry for BMP-2 performed. Staining was quantified using a standardized scoring system. Specimens were dichotomized into high or low expression level. Statistical analyses using log-rank, Wilcoxon, and Fisher exact test were performed for associations between BMP-2 protein level and clinicopathologic features and patient survival.

RESULTS

BMP-2 expression at any level was noted in 146 of 149 (98%) of samples. Tumors with high BMP-2 expression had higher rates of local failure compared with low-expressing tumors (17.3% vs 6.3%; P = .04). There was no significant association for BMP-2 expression level with tumor location, T stage, N stage, overall survival, regional failure, or distant failure.

CONCLUSION

Head and neck squamous cell carcinomas with high baseline BMP-2 protein level are associated with higher rates of local recurrence. These data have important implications for using rhBMP-2 in tissue engineering reconstructive approaches in the setting of cancer-related defects.

Bone formation induced by BMP-2 in human osteosarcoma cells

Our previous studies demonstrated that BMP-2 inhibits the tumorigenicity of cancer stem cells identified as cells with high aldehyde dehydrogenase activity (ALDH ^br cells) from the human osteosarcoma cell line OS99-1. We further investigated whether BMP-2 is capable of inducing bone formation in OS99-1 cells. Flow cytometry sorting was used to isolate tumorigenic ALDH ^br and non-tumorigenic ALDH ^lo cells. qRT-PCR was used to quantify the gene expression. A xenograft model was used to verify the bone formation in vivo . There was significantly higher mRNA expression of BMPR1B and BMPR2 in ALDH ^lo cells compared with that in ALDH ^br cells and the BMPR1B expression in ALDH ^lo cells was ∼8-fold higher compared to that in ALDH ^br cells. BMP-2 was also found to induce higher transcription of osteogenic markers Runx-2, Osterix (Osx), alkaline phosphatase (ALP) and collagen type I in ALDH ^lo cells compared to ALDH ^br cells, which were mediated by the canonical Smad signaling pathway. In vivo , BMP-2 was identified to induce bone formation in both ALDH ^br and ALDH ^lo cells. All animals receiving 1×10 ⁴ ALDH ^lo cells treated with 30 μ g of BMP-2 per animal showed bone formation within 1–2 weeks after injection in mice. Bone formation induced by BMP-2 in ALDH ^lo cells showed significantly more bone mineral content compared to that in ALDH ^br cells. BMP-2 induces bone formation in heterogeneous osteosarcoma cells and BMP-2 may have a promising therapeutic role for treating human osteosarcoma by inducing differentiation along an osteogenic pathway.

Adenovirus mediated knockdown of bone morphogenetic protein 2 inhibits human lung cancer growth and invasion in vitro and in vivo

Bone morphogenetic protein 2 (BMP-2) is a member of the TGF-beta superfamily of signaling molecules, and has been shown to function as a tumor suppressor involved in development and progression of many malignancies. BMP-2 has previously been reported to be closely correlated with lung cancer. But, the role and molecular mechanisms of BMP-2 in lung cancer have not yet been comprehensively explained. The present study aims to elucidate the role of BMP-2 in growth and invasion of human lung adenocarcinoma (LAC) in vitro and in vivo. Adenovirus vector-mediated BMP-2 small hairpin RNA (shBMP-2) was used to transfect into A549 LAC cells to determine the functional relevance of BMP-2 and tumor growth and invasion in vitro and in vivo, and further investigate the expression levels of BMP-2, vascular endothelial growth factor (VEGF), matrix metallopeptidase-9 (MMP-9), phosphatidylinositol 3-kinase p85alpha (PI3Kp85alpha) and phosphorylated AKT (p-AKT). As a result, LAC cell proliferation and invasion were significantly diminished by knockdown of BMP-2 indicated by MTT and Transwell assays, and cell apoptosis and cycle arrest were markedly induced indicated by flow cytometry. When BMP-2 expression was knocked down, the expression of PI3Kp85alpha, p-AKT, VEGF and MMP-9 was also down-regulated in LAC cells. In addition, the tumor volumes in LAC subcutaneous nude mouse model treated with shBMP-2 were significantly smaller than those in control and ad-GFP groups. Taken together, our findings indicate that knockdown of BMP-2 inhibits growth and invasion of LAC cells possibly via blockade of the PI3K/AKT signaling pathway, and BMP-2 may be a potential therapeutic target for lung cancer.

Cell cycle-regulatory cyclins and their deregulation in oral cancer

Oral cancer is a growth-related disorder, and cyclins are the prime regulators of cell division. Cyclins are associated with the pathogenesis of oral cancer and are considered valuable biomarkers for diagnosis and prognosis. These important molecules are regulated in many ways to achieve a gain in function and are involved in promoting neoplastic growth. While the causes of most cyclin overexpression are varied, these cyclins may be induced by buccal mucosal insult mainly with carcinogens that alter various pathways propelling oral cancer. Substantial experimental evidences support a link between oncogenic signaling pathways and the deregulation of cyclins in oral cancer. This review focuses on the mechanisms by which cyclins are regulated and promote oral oncogenesis.

rhBMP-2 has adverse effects on human oral carcinoma cell lines in vivo

OBJECTIVES/HYPOTHESIS

To establish the relevance of the bone morphogenetic protein (BMP) signaling pathway in human oral squamous cell carcinoma (OSCCA) cell lines and determine if there is a biologic impact of stimulating this pathway with recombinant human (rh) BMP-2.

STUDY DESIGN

In vitro laboratory investigations and in vivo analysis using an orthotopic animal model for oral cancer.

METHODS

Gene expression profiles for BMP-2 and components of the BMP-signaling pathway were determined using reverse transcriptase-polymerase chain reaction. In vivo effects were evaluated using Kaplan-Meier survival analysis and studying histopathologic changes in established tumor xenografts with or without rhBMP-2 pretreatment. A phosphokinase array was used to detect levels of activation in signaling kinases.

RESULTS

The BMP-2 gene was expressed in 90% of the 30 OSCCA cell lines tested. Gene expression of all components of the BMP-signaling pathway was highly conserved. Tumor xenografts established with rhBMP-2-treated cells showed more rapid local growth that resulted in worse animal survival as compared to the control group. These tumors had a more poorly differentiated morphology. Changes in protein kinases suggested interactions of BMP-2 signaling with the Wnt-β-catenin, and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways.

CONCLUSIONS

Human OSCCA cell lines frequently express BMP-2 and all necessary components of the BMP-signaling pathway. Exogenous treatment of human OSCCA cell lines with rhBMP-2 prior to engraftment in an orthotopic animal model caused the subsequent tumors to be more locally aggressive with worse survival. Continued caution should be used for considering rhBMP-2 for reconstruction of bone defects in oral cancer patients.

Immunoexpression of bone morphogenetic protein-2 (BMP-2), BMP receptor type IA, and BMP receptor type II in metastatic and non-metastatic lower lip squamous cell carcinoma

BACKGROUND

The aim of this study was to evaluate the expression of bone morphogenetic protein-2 (BMP-2), BMPR-IA, and BMPR-II in metastatic and non-metastatic lower lip squamous cell carcinoma (LLSCC).

METHODS

Twenty LLSCC with regional nodal metastasis and 20 LLSCC without metastasis were selected for analysis of the immunoexpression of BMP-2, BMPR-IA, and BMPR-II. The percentage of positive cells was evaluated according to the following parameters: score 1 (staining in 0-50% of cells), score 2 (staining in 51-75% of cells), and score 3 (staining in >75% of cells). Immunostaining intensity was evaluated according to the following scores: score 1 (absent or weak expression) and score 2 (strong expression).

RESULTS

Regarding the percentage of positive cells, most tumors with and without metastasis showed score 3 for both BMP-2 (P = 0.655) and BMPR-IA (P = 0.655). For BMPR-II, metastatic tumors exhibited higher percentage of positive cells in comparison with non-metastatic tumors (P = 0.049). With respect to immunostaining intensity, most LLSCCs with and without metastasis showed score 2 for BMP-2 (P = 1.000) and score 1 for BMPR-II (P = 1.000). For BMPR-IA, most metastatic tumors presented score 2, whereas most non-metastatic tumors showed score 1 (P < 0.001). Strong expression of BMPR-IA showed a statistically significant association with advanced clinical staging (P < 0.001) and high score of malignancy (P = 0.028).

CONCLUSIONS

The results of this study suggest that disturbances in the BMP-2 signaling pathway may be involved in the development of LLSCC and that the strong expression of BMPR-IA might be indicative of the development of metastasis in these lesions.