Oct-4 and CD44 in epithelial stem cells like of benign odontogenic lesions

Surrogate Immunohistochemical Markers of Proliferation and Embryonic Stem Cells in Distinguishing Ameloblastoma from Ameloblastic Carcinoma

PURPOSE

The current study aimed to investigate the use of surrogate immunohistochemical (IHC) markers of proliferation and stem cells to distinguish ameloblastoma (AB) from ameloblastic carcinoma (AC).

METHODS

The study assessed a total of 29 ACs, 6 ABs that transformed into ACs, and a control cohort of 20 ABs. The demographics and clinicopathologic details of the included cases of AC were recorded. The Ki-67 proliferation index was scored through automated methods with the QuPath open-source software platform. For SOX2, OCT4 and Glypican-3 IHC, each case was scored using a proportion of positivity score combined with an intensity score to produce a total score.

RESULTS

All cases of AC showed a relatively high median proliferation index of 41.7%, with statistically significant higher scores compared to ABs. ABs that transformed into ACs had similar median proliferation scores to the control cohort of ABs. Most cases of AC showed some degree of SOX2 expression, with 58.6% showing high expression. OCT4 expression was not seen in any case of AC. GPC-3 expression in ACs was limited, with high expression in 17.2% of ACs. Primary ACs showed higher median proliferation scores and degrees of SOX2 and GPC-3 expression than secondary cases. Regarding SOX2, OCT4 and GPC-3 IHC expression, no statistically significant differences existed between the cohort of ABs and ACs.

CONCLUSION

Ki-67 IHC as a proliferation marker, particularly when assessed via automated methods, was helpful in distinguishing AC from AB cases. In contrast to other studies, surrogate IHC markers of embryonic stem cells, SOX2, OCT4 and GPC-3, were unreliable in distinguishing the two entities.

The Stem Cell Expression Profile of Odontogenic Tumors and Cysts: A Systematic Review and Meta-Analysis

BACKGROUND

Stem cells have been associated with self-renewing and plasticity and have been investigated in various odontogenic lesions in association with their pathogenesis and biological behavior. We aim to provide a systematic review of stem cell markers' expression in odontogenic tumors and cysts.

METHODS

The literature was searched through the MEDLINE/PubMed, EMBASE via OVID, Web of Science, and CINHAL via EBSCO databases for original studies evaluating stem cell markers' expression in different odontogenic tumors/cysts, or an odontogenic disease group and a control group. The studies' risk of bias (RoB) was assessed via a Joanna Briggs Institute Critical Appraisal Tool. Meta-analysis was conducted for markers evaluated in the same pair of odontogenic tumors/cysts in at least two studies.

RESULTS

29 studies reported the expression of stem cell markers, e.g., SOX2, OCT4, NANOG, CD44, ALDH1, BMI1, and CD105, in various odontogenic lesions, through immunohistochemistry/immunofluorescence, polymerase chain reaction, flow cytometry, microarrays, and RNA-sequencing. Low, moderate, and high RoBs were observed in seven, nine, and thirteen studies, respectively. Meta-analysis revealed a remarkable discriminative ability of SOX2 for ameloblastic carcinomas or odontogenic keratocysts over ameloblastomas.

CONCLUSION

Stem cells might be linked to the pathogenesis and clinical behavior of odontogenic pathologies and represent a potential target for future individualized therapies.

Homeobox Genes in Odontogenic Lesions: A Scoping Review

BACKGROUND

Homeobox genes play crucial roles in tooth morphogenesis and development and thus mutations in homeobox genes cause developmental disorders such as odontogenic lesions. The aim of this scoping review is to identify and compile available data from the literatures on the topic of homeobox gene expression in odontogenic lesions.

METHOD

An electronic search to collate all the information on studies on homeobox gene expression in odontogenic lesions was carried out in four databases (PubMed, EBSCO host, Web of Science and Cochrane Library) with selected keywords. All papers which reported expression of homeobox genes in odontogenic lesions were considered.

RESULTS

A total of eleven (11) papers describing expression of homeobox genes in odontogenic lesions were identified. Methods of studies included next generation sequencing, microarray analysis, RT-PCR, Western blotting, in situ hybridization, and immunohistochemistry. The homeobox reported in odontogenic lesions includes LHX8 and DLX3 in odontoma; PITX2, MSX1, MSX2, DLX, DLX2, DLX3, DLX4, DLX5, DLX6, ISL1, OCT4 and HOX C in ameloblastoma; OCT4 in adenomatoid odontogenic tumour; PITX2 and MSX2 in primordial odontogenic tumour; PAX9 and BARX1 in odontogenic keratocyst; PITX2, ZEB1 and MEIS2 in ameloblastic carcinoma while there is absence of DLX2, DLX3 and MSX2 in clear cell odontogenic carcinoma.

CONCLUSIONS

This paper summarized and reviews the possible link between homeobox gene expression in odontogenic lesions. Based on the current available data, there are insufficient evidence to support any definite role of homeobox gene in odontogenic lesions.

Immunoexpression of stem cell markers SOX-2, NANOG AND OCT4 in ameloblastoma

Background

Ameloblastoma (AME) is characterized by a locally invasive growth pattern. In an attempt to justify the aggressiveness of neoplasms, the investigation of the role of stem cells has gained prominence. The SOX-2, NANOG and OCT4 proteins are important stem cell biomarkers.

Methodology

To verify the expression of these proteins in tissue samples of AME, dentigerous cyst (DC) and dental follicle (DF), immunohistochemistry was performed and indirect immunofluorescence were performed on the human AME (AME-hTERT) cell line.

Results

Revealed expression of SOX-2, NANOG and OCT4 in the tissue samples and AME-hTERT lineage. Greater immunostaining of the studied proteins was observed in AME compared to DC and DF (p < 0.001).

Conclusions

The presence of biomarkers indicates a probable role of stem cells in the genesis and progression of AME.

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.

Immunohistochemical analysis of SHH, SMO and GLI-1 proteins in epithelial odontogenic lesions

The present study analyzed the expression of proteins involved in the sonic hedgehog signaling pathway (SHH, SMO, and GLI-1) in benign epithelial odontogenic lesions (odontogenic keratocyst - OKC, ameloblastoma - AB, and adenomatoid odontogenic tumor - AOT) in order to identify the role of these proteins in the pathogenesis of these lesions. The sample consisted of 20 OKCs, 20 ABs, and 10 AOTs. The Kruskal-Wallis, Mann-Whitney U, and Spearman's (r) tests were used for statistical analysis, with the level of significance set at 5% (p < 0.05). The membrane/cytoplasmic expression of SHH was significantly higher in AB compared to AOT (p = 0.022) and OKC (p = 0.02). No differences were found in the membrane/cytoplasmic expression of SMO between the lesions studied. Regarding GLI-1, significant differences were observed at the nuclear level for AB and OKC compared to AOT (p < 0.0001). In addition, significant positive correlations were found between cytoplasmic and nuclear GLI-1 in AB (r = 0.482; p = 0.031) and OKC (r = 0.865; p < 0.0001), and between membrane/cytoplasmic SMO and cytoplasmic GLI-1 in AOT (r = 0.667; p = 0.035) and OKC (r = 0.535; p = 0.015). The results of this study confirm the participation of the sonic hedgehog signaling pathway in the pathogenesis of the lesions studied. Overexpression of SHH in ABs and nuclear expression of GLI-1 in ABs and OKCs indicate that these proteins contribute to the more aggressive behavior of these two lesions when compared to AOT.

Expression of a Tumor Stem Cell Marker (Aldehyde Dehydrogenase 1-ALDH1) in Benign Epithelial Odontogenic Lesions

The morphological diversity and different biological behaviors of human lesions has been attributed to the presence of cells with stem cell (SC) characteristics. Among SC markers, ALDH1 has been used in studies investigating different neoplasms and high expression of this marker was associated with clinicopathological features and prognosis in some groups. The aim of this study was to analyze the presence and distribution of SCs based on the expression of ALDH1 in epithelial odontogenic cysts and tumors. The sample consisted of 80 cases (20 dentigerous cysts (DCs), 20 odontogenic keratocysts (OKCs), 20 ameloblastomas (AMs), and 20 adenomatoid odontogenic tumors (AOTs). An immunoreactivity score was obtained from the percentage of positive cells and intensity of immunostaining. A level of 5% (p < 0.05) was adopted for the statistical tests. Immunoexpression of ALDH1 was observed in cytoplasm and nucleus-cytoplasm. The median scores indicated significantly higher expression in OKCs and DCs compared to AMs (p < 0.0001) and AOTs (p < 0.0001). In the tumor stroma and cystic capsule, immunoreactivity was detected in all odontogenic cysts studied and in 85% and 90% of AMs and AOTs, respectively. The expression of ALDH1 suggests the presence of SCs in the odontogenic lesions studied. Epithelial immunoexpression was higher in odontogenic cysts than in odontogenic tumors.

Expression of SOX2 and OCT4 in odontogenic cysts and tumors

Background

Aberrant expression of stem cell markers has been observed in several types of neoplasms. This trait attributes to the acquired stem-like property of tumor cells and can impact patient prognosis. The objective of this study was to comparatively analyze the expression and significance of SOX2 and OCT4 in various types of odontogenic cysts and tumors.

Methods

Fifty-five cases of odontogenic cysts and tumors, including 15 ameloblastomas (AM), 5 adenomatoid odontogenic tumors (AOT), 5 ameloblastic fibromas (AF), 5 calcifying odontogenic cysts (COC), 10 dentigerous cysts (DC) and 15 odontogenic keratocysts (OKC) were investigated for the expression of SOX2 and OCT4 immunohistochemically.

Results

Most OKCs (86.7 %) and all AFs expressed SOX2 in more than 50 % of epithelial cells. Its immunoreactivity was moderate-to-strong in all epithelial cell types in both lesions. In contrast, SOX2 expression was undetectable in AOTs and limited to the ameloblast-like cells in a minority of AM and COC cases. Most DCs showed positive staining in less than 25 % of cystic epithelium. Significantly greater SOX2 expression was noted in OKC compared with DC or AM, and in AF compared with COC or AOT. OCT4 rarely expressed in odontogenic lesions with the immunoreactivity being mild and present exclusively in OKCs.

Conclusions

SOX2 is differentially expressed in odontogenic cysts and tumors. This could be related to their diverse cells of origin or stages of histogenesis. The overexpression of SOX2 and OCT4 in OKC indicates the acquired stem-like property. Future studies should investigate whether the overexpression of OCT4 and SOX2 contributes to the aggressive behaviors of the tumors.

Activation of mesenchymal stem cells promotes new bone formation within dentigerous cyst

Background

Dentigerous cyst (DC) is a bone destructive disease and remains a challenge for clinicians. Marsupialization enables the bone to regenerate with capsule maintaining, making it a preferred therapeutic means for DC adjacent to vital anatomical structures. Given that capsules of DC are derived from odontogenic epithelium remnants at the embryonic stage, we investigated whether there were mesenchymal stem cells (MSCs) located in DC capsules and the role that they played in the bone regeneration after marsupialization.

Methods

Samples obtained before and after marsupialization were used for histological detection and cell culture. The stemness of cells isolated from fresh tissues was analyzed by morphology, surface marker, and multi-differentiation assays. Comparison of proliferation ability between MSCs isolated from DC capsules before (Bm-DCSCs) and after (Am-DCSCs) marsupialization was evaluated by Cell Counting Kit-8 (CCK-8), fibroblast colony-forming units (CFU-F), and 5′-ethynyl-2′-deoxyuridine (EdU) assay. Their osteogenic capacity in vitro was detected by alkaline phosphatase (ALP) and Alizarin Red staining (ARS), combined with real-time polymerase chain reaction (RT-PCR) and immunofluorescence (IF) staining. Subcutaneous ectopic osteogenesis as well as cranial bone defect model in nude mice was performed to detect their bone regeneration and bone defect repairability.

Results

Bone tissue and strong ALP activity were detected in the capsule of DC after marsupialization. Two types of MSCs were isolated from fibrous capsules of DC both before (Bm-DCSCs) and after (Am-DCSCs) marsupialization. These fibroblast-like, colony-forming cells expressed MSC markers (CD44+, CD90+, CD31−, CD34−, CD45−), and they could differentiate into osteoblast-, adipocyte-, and chondrocyte-like cells under induction. Notably, Am-DCSCs performed better in cell proliferation and self-renewal. Moreover, Am-DCSCs showed a greater osteogenic capacity both in vitro and in vivo compared with Bm-DCSCs.

Conclusions

There are MSCs residing in capsules of DC, and the cell viability as well as the osteogenic capacity of them is largely enhanced after marsupialization. Our findings suggested that MSCs might play a crucial role in the healing process of DC after marsupialization, thus providing new insight into the treatment for DC by promoting the osteogenic differentiation of MSCs inside capsules.

Expression of stem cell markers in stroma of odontogenic cysts and tumors

BACKGROUND

The stroma of odontogenic cysts/tumors may confer them differential biological behavior. We aimed to investigate the immunoexpression of stem cell markers (Nanog, SOX2, Oct4, and CD34) in the stroma of odontogenic cysts and tumors. CD34 was investigated exclusively as a marker for stromal fibroblast/fibrocyte cells (CD34 + SFCs). CD34 + SFCs were also investigated ultrastructurally.

METHODS

Ten cases each of primary odontogenic keratocyst (OKC), recurrent OKC, dentigerous cyst, ameloblastoma, unicystic ameloblastoma, odontogenic myxoma, and 7 syndromic OKC were included. Results were represented as the mean score (%) of positive cells/field for each marker for each study group. For CD34 + SFCs, results are presented as the mean number of cells/field for each type of lesion. Kruskal-Wallis and Spearman's correlation statistical tests were used; significance was set at P < .05.

RESULTS

All markers except Oct4 were expressed by stromal cells in all lesions. Expression of SOX2 was significantly higher in tumors than in cysts (P < .05). CD34 + SFCs were more frequent in cysts than in tumors. Ultrastructurally, CD34 + SFCs were identified for the first time in odontogenic lesions and showed characteristic bipolar/dendritic morphology.

CONCLUSION

Among examined stromal stem cell markers, only SOX2 distinguished tumors from cysts. CD34 + SFCs may also contribute to the biological behavior of odontogenic lesions.

Expression of keratin 15 in dentigerous cyst, odontogenic keratocyst and ameloblastoma

The etiology and pathogenesis of odontogenic lesions are poorly understood. Keratin 15 (K15) is a type I cytoskeletal protein that provides structural support to the cells and has been considered to be a stem cell marker. The aim of the present study was to evaluate the expression of K15 in the epithelial lining of dentigerous cysts (DCs), odontogenic keratocysts (OKCs) and ameloblastomas (ABs). The study included 41 samples of DCs (n=13), OKCs (n=12), and AB tissues (n=16). K15 protein expression was evaluated via immunohistochemistry and data were statistically analyzed using a Kruskal-Wallis test. K15 was expressed in the majority of the studied lesions with various distributions in the different study samples. The Kruskal-Wallis test revealed non-significant differences in the expression of K15 among the three odontogenic lesions (P=0.380). The present study confirmed the high expression of K15 in the different epithelial layers of DC, OKC and AB. This type of expression excludes the reliability of regarding K15 as a stem cell marker in DC, OKC and AB. However, K15 may reflect the abnormal differentiation of pathological epithelial cells in these lesions.