Osteoclast-related cytokines from biopsy specimens predict mandibular invasion by oral squamous cell carcinoma

Clinical, Radiological, and Pathological Correlation of Mandibular Invasion in Carcinoma Bucco-alveolar Complex

A prospective cross-sectional study was conducted to correlate clinically, radiologically, and pathologically the mandibular invasion in carcinoma bucco-alveolar complex. All biopsy-proven oral cavity cancer cases (64 patients) were assessed clinically and radiologically for involvement of the mandible. Preoperative clinicoradiological findings were compared with postoperative histopathological findings. In our study, oral cancer was 4 times more prevalent in males as compared to females and clinical evaluation was found to be highly sensitive in predicting mandibular invasion. Orthopantomogram showed sensitivity of 66.6% and specificity of 100%. CT scan showed sensitivity of 100% and specificity of 46% whereas MRI showed sensitivity of 54.5% and a specificity of 96%. MRI correlates well with final histopathology in predicting size of tumor. Prevalence of bony invasion in carcinoma oral cavity was 18%. We noted an inverse relation with tumor differentiation and mandibular invasion, and none of the verrucous carcinoma lesions showed mandibular invasion. Association of clinical T and N staging with postoperative histopathology was found to be statistically significant. Despite recent advances in molecular biology, radiological techniques, and newer modalities like visual surgical planning, exact measurement of bone invasion is still challenging. At present, CT scan and MRI along with clinical evaluation are widely used to evaluate mandibular invasion in carcinoma oral cavity, and all these are complementary to each other. The recent progress in tissue engineering technologies and stem cell biology has significantly promoted the development of regenerative reconstruction of jawbone defects.

Jaw Bone Invasion of Oral Squamous Cell Carcinoma Is Associated with Osteoclast Count and Expression of Its Regulating Proteins in Patients and Organoids

AIMS

Oral squamous cell carcinoma (OSCC) frequently invades the jaw. The exact mechanism of bone invasion remains unclear. This study investigates (premature) osteoclasts and the expression of its differentiation regulating proteins RANKL, OPG and RANK in patients with OSCC.

METHODS

Resection specimens from OSCC patients were divided into NI group (No Invasion), E group (Erosion) or I group (bone Invasion). Tissue sections were stained with Cathepsin K (osteoclast-counting), RANKL, OPG and RANK. The staining intensity was scored on different regions of the tumor: front, center, back and normal mucosa. Immunohistochemistry and qPCR for RANKL/OPG/RANK were performed on five head and neck squamous cell carcinoma (HNSCC) organoids.

RESULTS

The mean number of osteoclasts (I group) and premature osteoclasts (E group) was significantly higher compared to the NI group (p = 0.003, p = 0.036). RANKL expression was significantly higher in the tumor front and tumor center compared to normal mucosa (all groups). In the I group, RANKL and RANK expression was significantly higher in the tumor front compared to the tumor back and there was a trend of higher RANKL expression in the tumor front compared to the E group and NI group. qPCR showed a 20-43 times higher RANKL mRNA expression in three out of five tumor organoids compared to a normal squamous cell organoid line. There was no correlation between protein and mRNA expression in the HNSCC organoids.

CONCLUSIONS

These findings suggest that OSCCs induce bone invasion by stimulating osteoclast activation by regulating the production of RANKL and RANK proteins.

Determination of diagnostic and predictive parameters for vertical mandibular invasion in patients with lower gingival squamous cell carcinoma: A retrospective study

Vertical mandibular invasion of lower gingival squamous cell carcinoma (LGSCC) determines the method of resection, which significantly affects the patient's quality of life. Therefore, in mandibular invasion by LGSCC, it is extremely important to monitor progression, specifically whether invasion is limited to the cortical bone or has progressed to the bone marrow. This retrospective study aimed to identify the diagnostic and predictive parameters for mandibular invasion, particularly vertical invasion, to enable appropriate selection of the method of mandibular resection. Of the patients who underwent surgery for LGSCC between 2009 and 2017, 64 were eligible for participation in the study based on tissue microarrays (TMA) from surgical specimens. This study analyzed morphological features using computed tomography (CT), and metabolic characteristics using maximum standardized uptake value (SUVmax), peak value of SUV (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Moreover, immunohistochemical analysis of proteins, including parathyroid hormone-related protein (PTHrP), interleukin-6 (IL-6), E-cadherin, and programmed cell death-1 ligand 1 (PD-L1), was performed. Statistical analysis was performed using univariate logistic regression analysis with the forward selection method. The present study showed that MTV (≥2.9 cm3) was an independent diagnostic and predictive factor for positivity of mandibular invasion. Additionally, TLG (≥53.9 bw/cm3) was an independent diagnostic and predictive factor for progression to bone marrow invasion. This study demonstrated that in addition to morphological imaging by CT, the volume-based parameters of MTV and TLG on fluorine-18 fluorodeoxyglucose positron emission tomography were important for predicting pathological mandibular invasion in patients with LGSCC. A more accurate preoperative diagnosis of vertical mandibular invasion would enable the selection of appropriate surgical procedure for mandibular resection.

Loss of MMP-27 Predicts Mandibular Bone Invasion in Oral Squamous Cell Carcinoma

Simple Summary

The growth of oral squamous cell carcinoma into the mandible poses significant challenges to head and neck surgery. The resulting need for extensive procedures has a decisive influence on subsequent esthetics and function and therefore also on the patient’s quality of life. The molecular mechanism behind this remains obscure to date. Hence, we investigated the influence of MMP-27, Osteoprotegerin and RANKL, three proteins with importance in bone remodeling. The results showed that tumors exhibited less bone-invasive behavior in the presence of MMP-27. This may be an incentive for further studies to elucidate the molecular mechanisms of mandibular bone invasion in OSCC.

Abstract

Invasion of the mandibular bone is frequent in oral squamous cell carcinoma (OSCC), which often results in extensive ablative and reconstructive procedures for the patient. The purpose of this single-center, retrospective study was to identify and evaluate potential biomarkers and risk factors for bone invasion in OSCC. Initially, in silico gene expression analysis was performed for different HNSCC tumor T-stages to find factors associated with invasive (T4a) tumor growth. Afterwards, the protein expression of bone-metabolizing MMP-27, TNFRSF11B (Osteoprotegerin, OPG), and TNFSF11 (RANKL) was investigated via Tissue Microarrays (TMAs) for their impact on mandibular bone invasion. TMAs were assembled from the bone–tumor interface of primary OSCCs of the floor of the mouth and gingiva from 119 patients. Sixty-four carcinomas with patho-histological jaw invasion (pT4a) were compared to 55 carcinomas growing along the mandible without invasion (pT2, pT3). Tissue samples were additionally evaluated for patterns of invasion using the WPOI grading system. Statistical analysis of in silico data revealed decreased MMP-27 mRNA expression to be strongly associated with the pT4a-stage in OSCC, indicating invasive tumor growth with infiltration of adjacent anatomical structures. Our own clinico-pathological data on OSCCs presented a significant decrease of MMP-27 in tumors invading the nearby mandible (pT4a), compared to pT2 and pT3 tumors without bone invasion. Loss of MMP27 evolved as the strongest predictor of mandibular bone invasion in binary logistic regression analysis. To our knowledge, this is the first study investigating the role of MMP-27 expression in OSCC and demonstrating the importance of the loss of MMP-27 in mandibular bone invasion.

[Advances in molecular mechanisms of bone invasion by oral cancer]

Bone invasion by oral cancer is a common clinical problem, which affects the choice of treatment and predicts a poor prognosis. Unfortunately, the molecular mechanism of this phenomenon has not been fully elucidated. Current studies have revealed that oral cancer cells modulate the formation and function of osteoclasts through the expression of a series of signal molecules. Many signal pathways are involved in this process, of which receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factor-κB/osteoprotegerin signaling pathway attracted much attention. In this review, we introduce recent progress in molecular mechanisms of bone invasion by oral cancer.

CCL28-induced RARβ expression inhibits oral squamous cell carcinoma bone invasion

Oral squamous cell carcinoma (OSCC) frequently invades the maxillary or mandibular bone, and this bone invasion is closely associated with poor prognosis and survival. Here, we show that CCL28 functions as a negative regulator of OSCC bone invasion. CCL28 inhibited invasion and epithelial-mesenchymal transition (EMT), and its inhibition of EMT was characterized by induced E-cadherin expression and reduced nuclear localization of β-catenin in OSCC cells with detectable RUNX3 expression levels. CCL28 signaling via CCR10 increased retinoic acid receptor-β (RARβ) expression by reducing the interaction between RARα and HDAC1. In addition, CCL28 reduced RANKL production in OSCC and osteoblastic cells and blocked RANKL-induced osteoclastogenesis in osteoclast precursors. Intraperitoneally administered CCL28 inhibited tumor growth and osteolysis in mouse calvaria and tibia inoculated with OSCC cells. RARβ expression was also increased in tumor tissues. In patients with OSCC, low CCL28, CCR10, and RARβ expression levels were highly correlated with bone invasion. Patients with OSCC who had higher expression of CCL28, CCR10, or RARβ had significantly better overall survival. These findings suggest that CCL28, CCR10, and RARβ are useful markers for the prediction and treatment of OSCC bone invasion. Furthermore, CCL28 upregulation in OSCC cells or CCL28 treatment can be a therapeutic strategy for OSCC bone invasion.

Prognostic and predictive markers for perineural and bone invasion of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a growing problem worldwide. Several biological and molecular criteria have been established for making a prognosis of OSCC. One of the most important factors affecting the risk of tumor recurrence and overall prognosis is perineural invasion and bone invasion. Perineural invasion is defined as a tumor spreading and the ability of tumor cells to penetrate around or through the nerve tissue. Perineural invasion can cause the tumor to spread to distant areas from the primary tumor location. One possible explanation for this is the formation of microenvironment in the perineural space which may contain cellular factors that act on both nerve tissue and some types of tumor tissues. Bone invasion by OSCC has major implications for tumor staging, choice of treatment, outcome and quality of life. Oral SCCs invade the mandibular or maxillary bone through an erosive, infiltrative or mixed pattern that correlates with clinical behavior. Bone resorption by osteoclasts is an important step in the process of bone invasion by oral SCCs. Some cytokines (e.g. TNFα and PTHrP) lead to receptor activator of NF-κB ligand (RANKL) expression or osteoprotegerin (OPG) suppression in oral SCC cells and in cancer stromal cells to induce osteoclastogenesis. Oral SCCs provide a suitable microenvironment for osteoclastogenesis to regulate the balance of RANKL and OPG. A more molecular-based clinical staging and tailor-made therapy would benefit patients with bone invasion by OSCC.

Short-term RANKL exposure initiates a neoplastic transcriptional program in the basal epithelium of the murine salivary gland

Although salivary gland cancers comprise only ∼3-6% of head and neck cancers, treatment options for patients with advanced-stage disease are limited. Because of their rarity, salivary gland malignancies are understudied compared to other exocrine tissue cancers. The comparative lack of progress in this cancer field is particularly evident when it comes to our incomplete understanding of the key molecular signals that are causal for the development and/or progression of salivary gland cancers. Using a novel conditional transgenic mouse (K5:RANKL), we demonstrate that Receptor Activator of NFkB Ligand (RANKL) targeted to cytokeratin 5-positive basal epithelial cells of the salivary gland causes aggressive tumorigenesis within a short period of RANKL exposure. Genome-wide transcriptomic analysis reveals that RANKL markedly increases the expression levels of numerous gene families involved in cellular proliferation, migration, and intra- and extra-tumoral communication. Importantly, cross-species comparison of the K5:RANKL transcriptomic dataset with The Cancer Genome Atlas cancer signatures reveals the strongest molecular similarity with cancer subtypes of the human head and neck squamous cell carcinoma. These studies not only provide a much needed transcriptomic resource to mine for novel molecular targets for therapy and/or diagnosis but validates the K5:RANKL transgenic as a preclinical model to further investigate the in vivo oncogenic role of RANKL signaling in salivary gland tumorigenesis.

Hedgehog and TGFβ signaling converge on Gli2 to control bony invasion and bone destruction in oral squamous cell carcinoma

Oral Squamous Cell Carcinoma (OSCC) is the sixth most common cancer worldwide. OSCC invasion into the lymph nodes and mandible correlates with increased rates of recurrence and lower overall survival. Tumors that infiltrate mandibular bone proliferate rapidly and induce bone destruction. While survival rates have increased 12% over the last 20 years, this improvement is attributed to general advances in prevention, earlier detection, and updated treatments. Additionally, despite decades of research, the molecular mechanisms of OSCC invasion into the mandible are not well understood. Parathyroid Hormone-related Protein (PTHrP), has been shown to be essential for mandibular invasion in OSCC animal models, and our previous studies demonstrate that the transcription factor Gli2 increases PTHrP expression in tumor metastasis to bone. In OSCC, we investigated regulators of Gli2, including Hedgehog, TGFβ, and Wnt signaling to elucidate how PTHrP expression is controlled. Here we show that canonical Hedgehog and TGFβ signaling cooperate to increase PTHrP expression and mandibular invasion in a Gli2-dependent manner. Additionally, in an orthotopic model of mandibular invasion, inhibition of Gli2 using shRNA resulted in a significant decrease of both PTHrP expression and bony invasion. Collectively, our findings demonstrate that multiple signaling pathways converge on Gli2 to mediate PTHrP expression and bony invasion, highlighting Gli2 as a therapeutic target to prevent bony invasion in OSCC.

Upregulation of osteoprotegerin expression correlates with bone invasion and predicts poor clinical outcome in oral cancer

OBJECTIVES

We aimed to determine the prognostic significance of receptor activator of nuclear factor kappa-B ligand (RANKL), RANK and osteoprotegerin (OPG) in patients with oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The protein expression of RANKL, RANK and OPG was assessed by immunohistochemistry on pretreatment biopsies of 93 patients with locally advanced OSCC who received preoperative chemoradiotherapy (CRT). The primary endpoint was cancer-specific survival. Secondary endpoints were correlation of biomarkers with bone invasion and pathological tumor response. Kaplan-Meier curves and Cox regression models were used for survival analyses.

RESULTS

A significantly higher OPG expression was demonstrated in patients with malignant bone invasion and non-responders to CRT as compared to patients without bone invasion and responders (p=0.032 and p=0.033, respectively). Multivariate analysis revealed that higher OPG expression was independently associated with shorter cancer-specific survival (p=0.04). The expression status of RANKL and RANK was not significantly related to clinicopathological characteristics and had no impact on survival of OSCC patients.

CONCLUSION

Upregulation of OPG expression is associated with bone invasion, poor pathological tumor regression to neoadjuvant CRT, and worse long-term cancer-specific survival in patients with locally advanced OSCC. Our results indicate that OPG may be a novel prognostic biomarker in oral cancer.