Smoothened gene alterations in keratocystic odontogenic tumors

Identification of Molecular Mechanisms of Ameloblastoma and Drug Repositioning by Integration of Bioinformatics Analysis and Molecular Docking Simulation

Background

Ameloblastoma (AM) is a benign tumor locally originated from odontogenic epithelium that is commonly found in the jaw. This tumor makes aggressive invasions and has a high recurrence rate. This study aimed to investigate the differentially expressed genes (DEGs), biological function alterations, disease targets, and existing drugs for AM using bioinformatics analysis.

Methods

The data set of AM was retrieved from the GEO database (GSE132474) and identified the DEGs using bioinformatics analysis. The biological alteration analysis was applied to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Protein-protein interaction (PPI) network analysis and hub gene identification were screened through NetworkAnalyst. The transcription factor-protein network was constructed via OmicsNet. We also identified candidate compounds from L1000CDS2 database. The target of AM and candidate compounds were verified using docking simulation.

Results

Totally, 611 DEGs were identified. The biological function enrichment analysis revealed glycosaminoglycan and GABA (γ-aminobutyric acid) signaling were most significantly up-regulated and down-regulated in AM, respectively. Subsequently, hub genes and transcription factors were screened via the network and showed FOS protein was found in both networks. Furthermore, we evaluated FOS protein to be a therapeutic target in AMs. Candidate compounds were screened and verified using docking simulation. Tanespimycin showed the greatest affinity binding value to bind FOS protein.

Conclusions

This study presented the underlying molecular mechanisms of disease pathogenesis, biological alteration, and important pathways of AMs and provided a candidate compound, Tanespimycin, targeting FOS protein for the treatment of AMs.

2-Staged Surgical Protocol for Management of Large Odontogenic Keratocyst

The World Health Organisation classification and the treatment protocol for the odontogenic keratocyst (OKC), previously referred to as the keratocystic odontogenic tumour, were examined based on a study of the literature. Because not all OKCs have an identifiable protein patched homolog mutation, the idea of changing the management protocol for OKC in response to this shift in tumour category was met with scepticism and was not widely adopted. This study's objective was to outline a successful management plan for an odontogenic keratocyst in a patient who was 23 years old. The procedure for therapy involved marsupialisation, which was followed by enucleation, peripheral osteotomy, and the injection of 5 FFU. Following a 2-year observation period (clinical and radiological monitoring), it was found that bone regeneration was normal and there was no sign of a recurrence.

The Role of 5-Fluorouracil in Preventing Recurrence After Enucleation of Odontogenic Keratocyst: A Case Report

The odontogenic keratocyst (OKC) is known for its high recurrence rate and disputed treatment modalities. In this report, we review the literature elucidating the efficacy of 5-fluorouracil (5-FU) topical application for recurrent OKC, and discuss the management of an OKC with 5-FU after enucleation and a 12-month follow-up. A 38-year-old female patient with an aggressive OKC in the right mandible underwent surgical curettage followed by topical application of 5-FU. Regular follow-up examinations for 12 months (radiological evaluation at three, six, and 12-month intervals) showed no signs of recurrence, with complete resolution of the cystic lesion and gradual bone regeneration. New bone formation was identified in the radiographic follow-up.  This case demonstrates the potential efficacy of topical 5-FU as a promising treatment modality for OKC, warranting further research and validation. A novel and successful therapy for OKC is the topical application of 5-FU. After enucleation, topical application of 5-FU efficiently treats OKC, leading to normal bone healing and regeneration without any adverse local or systemic effects.

Safety and efficacy of adjunctive therapy in the treatment of odontogenic keratocyst: a systematic review

The odontogenic keratocyst (OKC) is a common cystic lesion in the jaw. Its management, however, is highly debated with no consensus on the best treatment option. Clinicians base their approach on treatment efficacy and associated morbidity. Management often consists of enucleation with peripheral ostectomy and adjunctive therapy to prevent recurrence. The aim of our systematic review was to evaluate the safety and efficacy of these different modalities. Embase, Medline, and Cochrane were searched according to the PRISMA guidelines for articles that presented non-syndromic patients with histopathologically confirmed OKC treated with 5-fluorouracil (5FU), Carnoy's solution (CS), or modified Carnoy's solution (MCS) as adjunctive therapy after enucleation and peripheral ostectomy. The outcomes of interest were safety (measured as adverse events) and efficacy (expressed as recurrence). Risk of bias was evaluated using the Newcastle-Ottawa scale. Four studies were included and 62 patients were evaluated. The results show that recurrence occurred only in patients treated with MCS. Reported adverse events were mostly limited to paraesthesia that could be permanent (in the CS and MCS treatment groups) or transient (across all adjunctive therapies). With the prohibition of CS, both MCS and 5FU are promising replacement adjunctive therapies. From a safety and efficacy perspective we consider 5FU, which was associated with the lowest recurrence and fewest adverse events, to be the most viable option. More high-evidence prospective studies, such as randomised controlled trials, with a longer follow-up period are necessary to draw definite conclusions.

Primary cilia and hypoxia-associated signaling in developmental odontogenic cysts in relation to autosomal dominant polycystic kidney disease - A novel insight

Developmental cysts are pathological epithelial-lined cavities arising in various organs as a result of systemic or hereditary diseases. Molecular mechanisms involved in the formation of developmental odontogenic cysts (OCs) are not fully understood yet; the cystogenesis of renal cysts originating from the autosomal dominant polycystic kidney disease (ADPKD) has been, however, explored in much greater detail. This narrative review aimed i) to summarize molecular and cellular processes involved in the formation and growth of developmental OCs, especially dentigerous cysts (DCs) and odontogenic keratocysts (OKCs), ii) to find if there are any similarities in their cystogenesis to ADPKD cysts, and, based on that, iii) to suggest potential factors, candidate molecules, and mechanisms that could be involved in the DC formation, thus proposing further research directions. Here we suggest a possible association of developmental OCs with primary cilia disruption and with hypoxia, which have been previously linked with cyst formation in ADPKD patients. This is illustrated on the imagery of tissues from an ADPKD patient (renal cyst) and from developmental OCs, supporting the similarities in cell proliferation, apoptosis, and primary cilia distribution in DC/OKC/ADPKD tissues. Based on all that, we propose a novel hypothesis of OCs formation suggesting a crucial role of mutations associated with the signaling pathways of primary cilia (in particular, Sonic Hedgehog). These can lead to excessive proliferation and formation of cell agglomerates, which is followed by hypoxia-driven apoptosis in the centers of such agglomerates (controlled by molecules such as Hypoxia-inducible factor-1 alpha), leading to cavity formation and, finally, the OCs development. Based on this, we propose future perspectives in the investigation of OC pathogenesis.

An evidence-based surgical algorithm for management of odontogenic keratocyst

The effective management of odontogenic keratocyst (OKC) remains a subject of interest and confusion in the oral and maxillofacial surgery literature. Currently, there is a lack of consensus regarding the most appropriate treatment for patients with OKC. Of the various treatment options available, no modality to date has been shown to demonstrate a zero or near-zero recurrence rates except wide resection with clear margins. With the prevailing dearth of evidence based surgical protocols for the management of patients with OKC in the literature, this study aims to present a surgical algorithm, based on meta-analysis results, that hopefully will be beneficial in enhancing treatment of patients with this condition. Also, new meta-analysis was done to compare between modified Carnoy's solution (MCS) and 5-fluorouracil (5-FU) in respect of recurrence rate of OKC. Using parameters like size, lesion type (primary or secondary), syndromic or solitary nature of the lesion, presence of cortical perforations, and locularity; we present a decision tree, to aid treatment planning and help attain the least chance of recurrence in the management of the OKC. There was very low-quality evidence indicating that application of 5-FU, after enucleation and peripheral ostectomy of OKCs, significantly lowered recurrence rate when compared to MCS (RR = 0.087, CI: 0.017 to 0.436, P value = 0.003).

Reawakening of Ancestral Dental Potential as a Mechanism to Explain Dental Pathologies

During evolution, there has been a trend to reduce both the number of teeth and the location where they are found within the oral cavity. In mammals, the formation of teeth is restricted to a horseshoe band of odontogenic tissue, creating a single dental arch on the top and bottom of the jaw. Additional teeth and structures containing dental tissue, such as odontogenic tumors or cysts, can appear as pathologies. These tooth-like structures can be associated with the normal dentition, appearing within the dental arch, or in nondental areas. The etiology of these pathologies is not well elucidated. Reawakening of the potential to form teeth in different parts of the oral cavity could explain the origin of dental pathologies outside the dental arch, thus such pathologies are a consequence of our evolutionary history. In this review, we look at the changing pattern of tooth formation within the oral cavity during vertebrate evolution, the potential to form additional tooth-like structures in mammals, and discuss how this knowledge shapes our understanding of dental pathologies in humans.

Genetic and Epigenetic Regulation of the Smoothened Gene (SMO) in Cancer Cells

(1) Background: The hedgehog (HH) signaling pathway is a key regulator of embryonic patterning, tissue regeneration, stem cell renewal, and cancer growth. The smoothened (SMO) protein regulates the HH signaling pathway and has demonstrated oncogenic activity. (2) Methods: To clarify the role of the HH signaling pathway in tumorigenesis, the expression profile of key HH signaling molecules, including SMO, PTCH1, GLI1, GLI2, and GLI3, were determined in 33 cancer cell lines and normal prostate cells and tissues. We performed a computational analysis of the upstream region of the SMO gene to identify the regulatory elements. (3) Results: Three potential CpG islands and several putative SMO promoter elements were identified. Luciferase reporter assays mapped key SMO promoter elements, and functional binding sites for SP1, AP1, CREB, and AP-2α transcription factors in the core SMO promoter region were confirmed. A hypermethylated SMO promoter was identified in several cancer cell lines suggesting an important role for epigenetic silencing of SMO expression in certain cancer cells. (4) Discussion: These results have important implications for our understanding of regulatory mechanisms controlling HH pathway activity and the molecular basis of SMO gene function. Moreover, this study may prove valuable for future research aimed at producing therapeutic downregulation of SMO expression in cancer cells.

Topical 5-fluorouracil application in management of odontogenic keratocysts

Aim & objectives

The aim of this study was to evaluate the efficacy of topical application of 5-fluorouracil (5-FU) after peripheral ostectomy, and compare it with other treatment modalities in the management of odontogenic keratocyst (OKC).

Materials &methods

This prospective study was conducted in the OMFS department for last seven years, wherein twenty seven patients of OKC were included and randomly allocated to the three treatment groups. Nine were treated by enucleation followed by application of modified carnoy solution (CS), eleven by peripheral ostectomy followed by application of 5-FU and eleven by segmental resection (SR). Follow-up ranged from 2 to 4 years to assess bone healing and record any recurrence of lesion.

Results

Amongst twenty seven patients, eighteen were males and nine females, age range 20-66 years. The most common location of OKC was posterior mandible. Complications included nerve injury, swelling, infection, and recurrence (66.6% after modified CS). Functional and aesthetic compromise was seen in resection patients whereas application of 5-FU had minimal nerve injuries, infection, swelling, no recurrence with no compromise in aesthetics and function.

Conclusion

Management of OKC by 5-FU is a novel surgical method having less morbidity, minimal recurrence, low cost, no functional or cosmetic deformity.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.

Immunohistochemical evaluation of Sonic Hedgehog signaling pathway proteins (Shh, Ptch1, Ptch2, Smo, Gli1, Gli2, and Gli3) in sporadic and syndromic odontogenic keratocysts

AIMS

The aim of this study was to compare the clinical and demographic features of 62 patients presenting sporadic odontogenic keratocysts (OKCs) or OKCs associated with nevoid basal cell carcinoma syndrome (NBCCS). In conjunction with this, we also evaluated the immunohistochemical expression of Shh, Ptch1, Ptch2, Smo, Gli1, Gli2 and Gli3 proteins in 86 OKCs. By doing this, we add to the understanding of the biology of this type of lesion, providing tools that will help facilitate the early diagnosis of NBCCS in those patients where the first manifestation is that of OKCs.

METHODS

This is a retrospective study; patients were classified into two groups: group 1 which consisted of those who were not affected by NBCCS (49 patients and 57 OKCs) and group 2 which consisted of those who were diagnosed with NBCCS (13 patients and 29 OKCs). The clinical and demographic features were studied and the immunohistochemical expression of Sonic Hedgehog proteins (Shh, Ptch1, Ptch2, Smo, Gli1, Gli2, and Gli3) was analyzed in all samples.

RESULTS

There was an increase in the expression of three proteins in the syndromic OKC, when compared to that of sporadic cysts. Shh and Gli1 showed higher cytoplasmic expression, while Smo revealed stronger nuclear and cytoplasmic expressions.

CONCLUSION AND CLINICAL RELEVANCE

Our findings suggest that the expression patterns of important Shh pathway proteins can represent valuable markers for early diagnosis of NBCCS-associated OKCs, as the major criterion for the diagnosis of NBCCS is currently based on the late appearance of basal cellular carcinomas. Thus, standardizing a new diagnostic tool for diagnosis of NBCCS could be of great importance in the identification of therapeutic targets. We therefore suggest, as based on our findings, that OKCs showing high expression of Shh, Smo, and Gli1 are potentially associated with NBCCS.

Topical 5-Fluorouracil is a Novel Targeted Therapy for the Keratocystic Odontogenic Tumor

PURPOSE

The antimetabolite drug, 5-fluorouracil (5-FU), is used in the treatment of various cancers, including basal cell carcinomas (BCCs). The authors hypothesized that keratocystic odontogenic tumors (KOTs) would respond to 5-FU treatment because of their similarities to BCCs in molecular etiopathogenesis.

MATERIALS AND METHODS

An ambispective cohort study of the treatment efficacy of topical 5-FU on KOTs was conducted. Independent variables included the topical application of 5% 5-FU or modified Carnoy's solution (MC) after enucleation and peripheral ostectomy at the University of Toronto from 2006 through 2014. Outcome variables included time to recurrence and peripheral nerve injury. KOT specimens in these patients were immunostained with p53, Ki-67, thymidylate synthetase (TS), thymidylate phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) antibodies. Semiquantitative staining scores were calculated for all immunohistochemistry sections examined. Descriptive statistics were computed using Fisher exact test and Kaplan-Meier analysis as appropriate with the P value set at .05.

RESULTS

Thirty-two patients with 32 KOTs were reviewed (41% in women and 59% in men). There were no KOT recurrences in the 5-FU group (n = 11), whereas there were 4 recurrences in the MC group (n = 21; P = .190). There was a significantly lower incidence of inferior alveolar nerve paresthesia with 5-FU treatment (P = .039). Immunohistochemical staining showed upregulation of TP (P < .0001) and DPD (P < .0001) and no change in TS (P > .05) in inflamed KOTs.

CONCLUSIONS

5-FU effectively treats KOTs with less postoperative morbidity than conventional treatment with MC. Low TS and upregulated TP expressions in inflamed KOTs suggest increased 5-FU efficacy in inflamed KOTs. Topical 5-FU is a novel therapy for KOTs and provides a targeted molecular approach to treatment.