osteoprotegerin and Ameloblastoma

Ameloblastomas are the most common odontogenic epithelial tumors with high recurrence rate. The aim of this study was to identify apoptosis-related genes with recurrence of ameloblastomas and to evaluate its feasibility as a prognostic marker and as a target molecule preventing from recurrence.. Public microarray data were analyzed. To evaluate their expression in ameloblastoma patients, immunohistochemical staining was performed in 89 human ameloblastoma tissues. Quantitative PCR was performed by use of ameloblastoma cell line (AM-1). Fluorescence activated cell sorting analysis and western blotting were conducted following transfection with siRNA. Further, AM-1 cells were implanted in the renal subcapsular layer of immunodeficient mice.. Microarray data analysis revealed that osteoprotegerin (OPG) and B-cell lymphoma 2 (Bcl-2) were the two most upregulated genes in ameloblastoma. Only Bcl-2 expression was significantly (p = 0.020) associated with recurrence in conservative treatment group (n = 17) among 89 patients. Silencing of Bcl-2 increased apoptosis in AM-1 cells in vitro and inhibited tumor nodule formation of AM-1 cells in vivo.. These results suggest that Bcl-2 expression is a useful biomarker to predict recurrence of ameloblastomas, and as a therapeutic target molecule to prevent recurrence of ameloblastoma.

Topics: Adult; Ameloblastoma; Animals; Apoptosis; Female; Humans; Jaw Neoplasms; Lymphoma, B-Cell; Male; Mice; Middle Aged; Neoplasm Recurrence, Local; Osteoprotegerin; Prognosis; Proto-Oncogene Proteins c-bcl-2

Reduced expression of syndecan-1 (CD138), increased proliferation index, and modifications in the expression of the molecular RANK/RANKL/OPG triad are related to an intensified potential of aggressiveness and invasion of diverse tumors and cysts. The aim was to compare the expression of Ki-67, CD138, and the molecular triad RANK, RANKL, and OPG in odontogenic keratocysts (OKC), unicystic ameloblastomas (UA), and dentigerous cysts (DC).. Immunohistochemistry for Ki-67, CD138, RANK, RANKL, and OPG was performed in 58 odontogenic cystic lesions (22 OKC, 17 DC, and 19 UA).. A higher expression of Ki-67 was identified in OKC as compared to UA (. Higher RANKL expression together with the reduction on CD138 expression in UA could be linked to a greater invasive and destructive potential, while the increased proliferation rate observed in OKC could be related to its continuous intrabony growth. The expansion of DC does not seem to be related to such factors, justifying the different therapeutic approaches proposed for each of these entities.

Topics: Ameloblastoma; Biomarkers; Dentigerous Cyst; Gene Expression Regulation; Humans; Jaw Neoplasms; Ki-67 Antigen; Odontogenic Cysts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Syndecan-1

Solid ameloblastoma demonstrates a more invasive behavior compared to unicystic. The follicular ameloblastoma is referred that may present a higher recurrence potential compared to the plexiform variant. In this study, the different ameloblastoma clinical types and histopathological variants were examined regarding the expression of bone remodeling-related molecules OPG, RANKL, and TRAIL.. Immunostained sections of 29 solid and 11 unicystic ameloblastoma cases were semi-quantitatively evaluated and analyzed using Mann-Whitney or Kruskal-Wallis tests.. Solid ameloblastoma showed a significantly increased OPG expression (P = 0.004) associated with the follicular (P < 0.05) than the plexiform or mixed pattern. Lack or low immunoreactivity for RANKL was noted in 79.3% of the solid tumors. A statistically significant result (P < 0.05) was found in the unicystic ameloblastoma for differences by the histopathological pattern (no RANKL expression when plexiform pattern was seen compared to follicular). Comparison between the clinical types showed differences regarding the ratio of OPG/RANKL and TRAIL/RANKL expression. Higher OPG expression over RANKL was observed in 86.2% of the solid compared to 36.4% of the unicystic type. There was no difference in the ratio of TRAIL/RANKL expression in the unicystic, whereas 55.2% of the solid ameloblastomas showed a greater TRAIL expression over RANKL.. Our results suggest OPG overexpression and RANKL underexpression in solid ameloblastoma; this may reflect a possible prevalence of the OPG/TRAIL over the OPG/RANKL signaling pathway, resulting in inactivation of TRAIL-induced apoptosis in ameloblastic cells. In unicystic ameloblastoma, the RANKL/OPG expression immunoprofile among histological variants is compatible with the reported biologic behavior.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Apoptosis; Bone Remodeling; Child; Female; Humans; Immunohistochemistry; Jaw Neoplasms; Male; Middle Aged; Neoplasm Recurrence, Local; Osteoprotegerin; RANK Ligand; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand; Young Adult

To determine the distribution patterns of bone resorption regulators, receptor activator of nuclear factor κ-B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in recurrent ameloblastoma (RAs) and to clarify their impact on the biologic behavior of these neoplasms.. Fifteen paraffin-embedded RA cases were subjected to immunohistochemistry for expression of RANK, RANKL, and OPG.. The RANK-RANKL-OPG triad was heterogeneously detected in RA samples. RANK, essential for osteoclast differentiation, was strongly expressed in tumoral epithelium. Conversely, RANKL, an osteoclast activator, was markedly underexpressed, and protein localization was predominantly stromal. OPG, an osteoclastogenesis inhibitory factor, was detected in neoplastic epithelium more than in stroma, suggesting functional inactivation of RANKL. Most RA (n = 12/15; 80%) exhibited a bimolecular spatial expression pattern, the most common being RANK-positive/OPG-positive (n = 8/15; 53.3%). All three proteins showed no significant correlation with the clinical/histopathologic parameters in RA patients (P > .05).. The RANK(+)/RANKL(low/-)/OPG(+) phenotype observed in RA suggests an altered local bone metabolism characterized by low bone resorptive activity in these recurrent tumors.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Child; Female; Humans; Immunohistochemistry; Male; Mandibular Neoplasms; Middle Aged; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

The aim of the present study was to compare the immunohistochemical detection of receptor activator nuclear κB ligand (RANKL) and osteoprotegerin (OPG) in radicular cysts (RCs), dentigerous cysts (DCs), solid ameloblastomas (SAs), and keratocystic odontogenic tumors (KOTs).. A total of 20 RCs, 20 DCs, 20 KOTs, 14 dental follicles (DFs), and 18 SAs were evaluated by immunohistochemistry using anti-RANKL and anti-OPG antibodies. The analysis was quantitative, and the number of positive cells was counted in 10 microscopic high-power fields (400×).. The DFs, KOTs, and SAs showed higher expression of RANKL than did the RCs and DCs in the epithelium (P < .05). The epithelial expression of OPG was higher in the DFs, KOTs, RCs, and DCs than in the SAs (P < .05). The ratio of OPG less than RANKL was more frequent in SAs and OPG greater than RANKL in DCs (P < .05).. Our results have shown differences in RANKL and OPG detection in the odontogenic cysts and tumors studied. The higher RANKL and lower OPG detection in SA could play a role in bone resorption, compatible with the tumor's biologic behavior.

Topics: Ameloblastoma; Biomarkers, Tumor; Cell Count; Coloring Agents; Dental Sac; Dentigerous Cyst; Epithelial Cells; Humans; Immunohistochemistry; Odontogenic Cysts; Odontogenic Tumors; Osteoprotegerin; Radicular Cyst; RANK Ligand; Stromal Cells

The aim of this study was to evaluate the immunohistochemical expression of molecules involved in osteoclastogenesis, including the receptor activator of nuclear factor kappa B (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) in odontogenic keratocysts (OKCs), which has been named as a keratocystic odontogenic tumour by the WHO, and compare their expression with radicular cysts and ameloblastomas. RANK is a member of tumour necrosis factor receptor family and it is activated by RANK ligand. OPG binds to RANKL and inactivates it. The imbalance of these factors could cause the differential bone resorption activity in some diseases and tumours. The expression of these molecules was evaluated in ameloblastomas (n = 20), OKCs (n = 20), and radicular cysts (n = 20) by immunohistochemistry. Immunohistochemical reactivity for RANK, RANKL, and OPG was detected in neoplastic and nonneoplastic epithelium and connective tissue cells. RANK showed the greatest expression in OKCs followed by ameloblastomas, with the lowest expression seen in radicular cysts. Expression of RANKL was detected in all lesions and no significant differences were observed between groups. OPG was expressed very low in all groups. In the stroma, the number of RANK positive cells was higher in OKCs when compared with ameloblastomas and radicular cysts but radicular cyst had higher numbers of RANKL positive cells in the stroma than ameloblastomas. The molecular system of RANK/RANKL/OPG is variably expressed in OKCs, radicular cysts, and ameloblastomas and this system may be involved in the osteoclastogenic mechanisms in OKCs and ameloblastomas. Advanced studies could further clarify the role of RANK, RANKL, and OPG in mediating tumour associated bone osteolysis.

Topics: Adult; Ameloblastoma; Female; Humans; Immunohistochemistry; Jaw Neoplasms; Male; Middle Aged; Odontogenic Cysts; Osteoclasts; Osteolysis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

Ameloblastoma, a common odontogenic tumor located in jaws, generally leads to severe damage to patient's complexion and masticatory function. To expand in jaws, ameloblastoma must have a mechanism of resorbing the surrounding bone. Our objective was to explore the bone-resorption mechanism of ameloblastoma by observing the role of Receptor activator of nuclear factor kappa B ligand (RANKL) and matrix metalloproteinase-9 (MMP-9) in the bone-resorption process.. In the study, the expression of RANKL and MMP-9 in ameloblastoma was detected using immunohistochemistry (IHC) and RT-PCR. Then, co-culture system of ameloblastoma cells and bone marrow cells from neonatal rabbit was erected to observe the potential of ameloblastoma cells to induce osteoclastogenesis. Finally, the induced osteoclasts were used for in vitro bone-resorption assay. In the co-culture system and the bone-resorption assay, the selective inhibitor of RANKL and MMP-9, osteoprotegerin (OPG) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were, respectively, used for observing the role of RANKL and MMP-9.. The expression of RANKL and MMP-9 in ameloblastoma was confirmed. Ameloblastoma cells were found to induce bone marrow cells from neonatal rabbit differentiate into osteoclasts with bone-resorption activity. In addition, OPG was found to, respectively, have markedly inhibitory effect on osteoclastogenesis (P<0.01), and slightly inhibitory action on bone resorption (P<0.05).. Ameloblastoma cells had the potential to induce osteoclastogenesis. Moreover, RANKL played an essential role in the in vitro osteoclast formation and bone resorption induced by ameloblastoma cells.

Topics: Acid Phosphatase; Ameloblastoma; Animals; Animals, Newborn; Biomarkers; Bone Marrow Cells; Bone Resorption; Calcium; Cell Count; Cell Culture Techniques; Cell Differentiation; Cells, Cultured; Coculture Techniques; Dentin; Female; Humans; Immunohistochemistry; Isoenzymes; Male; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Osteoclasts; Osteoprotegerin; Rabbits; RANK Ligand; Reverse Transcriptase Polymerase Chain Reaction; Tartrate-Resistant Acid Phosphatase; Tissue Inhibitor of Metalloproteinase-1

The aim of this study was to compare the expression of nuclear factor kappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in odontogenic epithelial tumors and dentigerous cysts.. The expression of these molecules was evaluated in solid/multicystic ameloblastomas (n = 12) and unicystic ameloblastomas (n = 8), keratocystic odontogenic tumors (n = 19), dentigerous cysts (n = 9), and dental follicles (n = 9) by immunohistochemistry.. In odontogenic epithelium, a similar expression of RANK, RANKL, and OPG was observed in all samples. With regard to stroma, the number of RANK-positive and RANKL-positive cells was higher in solid/multicystic ameloblastomas compared with dentigerous cysts. Dental follicles had lower numbers of RANK-positive, RANKL-positive, and OPG-positive cells than solid/multicystic ameloblastomas and keratocystic odontogenic tumors. The majority of solid/multicystic ameloblastomas (75%) and unicystic ameloblastomas (62.5%) had higher numbers of RANKL-positive than OPG-positive cells. In contrast, 62.4% of keratocystic odontogenic tumors and 100% of dentigerous cysts exhibited a higher content of OPG-positive than RANKL-positive cells.. Our results indicate differences in the RANK, RANKL, and OPG expression in odontogenic epithelial tumors. The imbalance of these factors could contribute to the differential bone/tooth resorption activity in these lesions.

Topics: Ameloblastoma; Cell Count; Dentigerous Cyst; Epithelial Cells; Gene Expression; Humans; Jaw Neoplasms; NF-kappa B; Odontogenic Tumors; Osteolysis; Osteoprotegerin; RANK Ligand; Root Resorption; Statistics, Nonparametric; Stromal Cells

Osteoprotegerin (OPG) is a useful receptor in inhibiting Receptor Activator of NFkappaB Ligand (RANKL) in inducing osteoclastogenesis. Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) is a potent apoptosis-inducing ligand in ameloblastomas. Since OPG has been reported to bind to TRAIL as well, the effect of OPG in TRAIL's function in inducing apoptosis should also be investigated. To investigate on the expression of OPG in ameloblastomas, immuhistochemistry, immunofluorescence and Western blot were performed. From the immunohistochemistry results, we found that OPG was expressed in ameloblastoma tissues. Expression of OPG was clearly seen in AM-1 cells by immunofluorescence as well. Additionally, Western blot analysis confirmed OPG expression in ameloblastoma tissues and AM-1 cells. To investigate on the potential of TNFalpha, TRAIL and RANKL in inducing apoptosis, we performed an apoptosis assay. From the apoptosis assay, we found that TRAIL had the highest potential in inducing apoptosis compared to TNFalpha and RANKL. To investigate the binding of OPG with RANKL and TRAIL, we performed a binding assay. We noticed that OPG preferably bind with RANKL than TRAIL. However, at low levels of RANKL, marked binding of OPG with TRAIL was seen. As we suspected that the binding of OPG and TRAIL might cause the effect of TRAIL in inducing apoptosis in ameloblastomas, we combined the treatment of OPG and TRAIL in AM-1 cells. From the apoptosis assay, we found that under treatment of OPG, TRAIL's function in inducing apoptosis was suppressed. These data suggest that by binding with TRAIL, OPG suppressed TRAIL's function in inducing apoptosis in ameloblastomas.

Topics: Ameloblastoma; Apoptosis; Blotting, Western; Female; Humans; Jaw Neoplasms; Male; Osteoprotegerin; TNF-Related Apoptosis-Inducing Ligand

To clarify the roles of osteoclast regulatory factors in progression of odontogenic tumors, expression of parathyroid hormone-related protein (PTHrP), osteoclast differentiation factor (ODF)/receptor activator of nuclear factor-kappaB ligand (RANKL), and osteoclastogenesis inhibitory factor (OCIF)/osteoprotegerin (OPG) were analyzed in ameloblastomas as well as tooth germs.. Tissue specimens of nine tooth germs and 36 benign and one malignant ameloblastomas were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry for the expression of PTHrP, ODF/RANKL, and OCIF/OPG.. Expression of PTHrP, ODF/RANKL, and OCIF/OPG mRNA was detected in all tooth germ and ameloblastoma samples. Immunohistochemical reactivity for PTHrP was recognized in both normal and neoplastic odontogenic epithelial cells. In ameloblastomas, PTHrP reactivity in peripheral columnar or cuboidal cells was stronger than that in central polyhedral cells, and keratinizing cells showed increased PTHrP reactivity. ODF/RANKL and OCIF/OPG were expressed predominantly in mesenchymal cells rather than in odontogenic epithelial cells in both tooth germs and ameloblastomas. Epithelial ODF/RANKL and OCIF/OPG expression was slightly lower in ameloblastomas than in tooth germs. Tumor cells in plexiform ameloblastomas showed slightly higher reactivity for PTHrP and ODF/RANKL than tumor cells in follicular ameloblastomas.. Expression of PTHrP, ODF/RANKL and OCIF/OPG in tooth germs and ameloblastomas suggests that these factors might locally regulate bone metabolism and dynamics in tooth development as well as in progression of ameloblastomas. These factors might also be involved in tumor cell differentiation and/or tumor tissue structuring in ameloblastomas.

Topics: Ameloblastoma; Carrier Proteins; Cell Differentiation; Epithelial Cells; Glycoproteins; Humans; Keratinocytes; Ligands; Membrane Glycoproteins; Mesoderm; NF-kappa B; Odontogenesis; Osteoclasts; Osteoprotegerin; Parathyroid Hormone-Related Protein; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Statistics, Nonparametric; Tooth Germ; Tumor Necrosis Factor-alpha

RANKL (receptor activator of nuclear factor kappaB ligand) promotes osteoclast differentiation, stimulates osteoclast activity, and prolongs osteoclast survival and adherence to bone. Abnormalities of the RANKL/RANK/osteoprotegerin system have been implicated in a range of diseases, including osteoporosis. To date, no work has been done in osteolytic lesions of the facial skeleton. In this study, specimens of ameloblastomas, dentigerous cysts, odontogenic keratocysts, and radicular cysts were subjected to immunohistochemical analysis for RANKL and tartrate-resistant acid phosphatase (TRAP). Immunofluorescence staining for TRAP was visualized under confocal microscopy. All specimens demonstrated distinct positive immunoreactivity to RANKL and TRAP. The TRAP-positive cells also stained with in situ hybridization for human calcitonin receptor, a definitive marker for osteoclasts. Mononuclear pre-osteoclasts were observed to migrate from blood to the connective tissue stroma and multinucleate toward the bone surface. It can be concluded that RANKL plays a role in bone resorption in osteolytic lesions of the facial skeleton.

Topics: Acid Phosphatase; Ameloblastoma; Dentigerous Cyst; Facial Bones; Glycoproteins; Humans; Immunohistochemistry; In Situ Hybridization; Isoenzymes; Jaw Neoplasms; Odontogenic Cysts; Osteolysis; Osteoprotegerin; Radicular Cyst; Receptors, Calcitonin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction; Tartrate-Resistant Acid Phosphatase