Despite advancements in therapeutic approaches, radiotherapy and cisplatin-based chemotherapy remain primary noninvasive treatments for patients with oral squamous cell carcinoma (OSCC). Moreover, the 5-year survival rate for patients with OSCC has remained almost unchanged for several decades, and many side effects of chemotherapy still exist. In this study, three-dimensional (3D) models of OSCC were established using fibroblasts, and the efficacy of various biological inhibitors was evaluated. A culture of epithelial cells with two types of fibroblasts (hTERT-hNOFs and cancer-associated fibroblasts) within a type I collagen matrix resulted in the formation of a continuous layer of tightly packed cells compared to models without fibroblasts. Furthermore, the effects of biological chemicals, including Y27632, latrunculin A, and verteporfin, on these models were investigated. The stratified formation of the epithelial layer and invasion in OSCC 3D-culture models were effectively inhibited by verteporfin, whereas invasion was weakly inhibited by Y27632 and latrunculin. Collectively, the developed OSCC 3D-culture models established with fibroblasts demonstrated the potential for drug screening, with verteporfin showing promising efficacy.

Oral bacterial infections substantially affect the development of various periodontal diseases and oral cancers. However, the molecular mechanisms underlying the association between Fusobacterium nucleatum (F. nucleatum ), a major periodontitis (PT)-associated pathogen, and these diseases require extensive research. Previously, our RNAsequencing analysis identified a few hundred differentially expressed genes in patients with PT and peri-implantitis (PI) than in healthy controls. Thus, in the present study using oral squamous cell carcinoma (OSCC) cells, we aimed to evaluate the effect of F. nucleatum infection on genes that are differentially regulated in patients with PT and PI. Human oral squamous cell carcinoma cell lines OSC-2O, HSC-4, and HN22 were used. These cells were infected with F. nucleatum at a multiplicity of infection of 100 for 3 hours at 37℃ in 5% CO2. Gene expression was then measured using reverse-transcription polymerase chain reaction. Among 18 genes tested, the expression of CSF3, an inflammation-related cytokine, was increased by F. nucleatum infection. Additionally, F. nucleatum infection increased the phosphorylation of AKT, p38 MAPK, and JNK in OSC-20 cells. Treatment with p38 MAPK (SB202190) and JNK (SP600125) inhibitors reduced the enhanced CSF3 expression induced by F. nucleatum infection. Overall, this study demonstrated that F. nucleatum promotes CSF3 expression in OSCC cells through p38 MAPK and JNK signaling pathways, suggesting that p38 MAPK and JNK inhibitors may help treat F. nucleatum-related periodontal diseases by suppressing CSF3 expression.

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, and it has been steadily increasing in worldwide. Pituitary tumor transforming gene 1 (PTTG1) has been known as oncogene in a verity of cancers. Nevertheless, the expression and role of PTTG1 in OSCC progression remains largely unexplored. In this study, clinical datasets were analyzed to assess the genetic impact of PTTG1 on OSCC progression and to identify its functional roles in OSCC cell lines. We analyzed the expression of PTTG1 in head and neck squamous cell carcinoma (HNSC) and OSCC using databases form the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). To investigate the effect of PTTG1 on proliferation and migration abilities in OSCC cell lines, following the knockdown of PTTG1 in HSC-2 and SCC-9 cell lines, we analyzed the proliferation and metastatic abilities of OSCC cells using EdU and Boyden chamber assays. Our database analysis revealed that PTTG1 was significantly overexpressed in tumor tissues compared to normal tissues. Moreover, its expression correlated with clinical parameters of OSCC. In vitro experiments demonstrated that depletion of PTTG1 suppressed the ability of cell proliferation and migration in both HSC-2 and SCC-9 cell lines. In conclusion, our study suggests that PTTG1 may act as an oncogene in OSCC. These findings provide new insights into the mechanisms and clinical implications of PTTG1 expression in OSCC patients.

Patients with oral squamous cell carcinoma (OSCC) generally have an elevated expression of homeobox C6 (HOXC6) gene. We found that HOXC6 was the significantly upregulated gene in hypopharyngeal squamous cell carcinoma (FaDu) cells using RNA-seq analysis. However, it remains unclear whether HOXC6 plays a role in tumor process mechanism. Our study aimed to explore the potential oncogenic role and the detailed molecular mechanism of HOXC6 in FaDu cells. In this study, Sirt1 was validated to be overexpressed in FaDu cells and associated with HOXC6 expression. Overexpression of HOXC6 promoted the cell colony formation, whereas inhibition of Sirt1 by Sirt1 inhibitor EX527 reduced cell proliferation/colony formation and migration, and induced apoptosis in HOXC6 overexpressed FaDu cells. Interestingly, mechanistic study showed that EX527 mediated Sirt1 suppression led to decreased HOXC6 expression and upregulation of Sirt1 significantly increased the expression of HOXC6. HOXC6 was shown to cooperate with Sirt1 to enhance cell survival. We propose that HOXC6 promotes cell growth/colony formation, and that the HOXC6 may be a progression of hypopharyngeal carcinoma by activating Sirt1 pathways.

Oral squamous cell carcinoma (OSCC), which accounts for approximately 90% of oral cancers, has a high rate of local recurrence and a poor prognosis despite improvements in treatment. Exosomes released from OSCC cells promote cell proliferation and metastasis. Although it is clear that the biogenesis of exosomes is mediated by the endosomal sorting complex required for transport (ESCRT) machinery, the gene expression pattern of ESCRT, depending on the cell type, remains elusive. The exosomal release from the human OSCC cell lines, HSC-3 and HSC-4, and their corresponding gefitinib-resistant sub-cell lines, HSC-3/GR and HSC-4/GR, was assessed by western blot and flow cytometry. The levels of ESCRT machinery proteins, including Hrs, Tsg101, and Alix, and whole-cell ubiquitination were evaluated by western blot. We observed that the basal level of exosomal release was higher in HSC-3/GR and HSC-4/GR cells than in HSC-3 and HSC-4 cells, respectively. Long-term gefitinib exposure of each cell line and its corresponding gefitinib-resistant sub-cell line differentially induced the expression of the ESCRT machinery. Furthermore, whole-cell ubiquitination and autophagic flux were shown to be increased in gefitinib-treated HSC-3 and HSC-4 cells. Our data indicate that the expression patterns of the ESCRT machinery genes are differentially regulated by the characteristics of cells, such as intracellular energy metabolism. Therefore, the expression patterns of the ESCRT machinery should be considered as a key factor to improve the treatment strategy for OSCC.

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancer and is associated with high recurrence, poor treatment, and low survival rates. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates the response to hypoxia, a major factor in the tumor microenvironment that affects tumor development and progression in various cancer types. However, microRNA (miRNA) sequence analysis revealed that only a few miRNAs targeting HIF-1α had been discovered. In the present study, we investigated HIF-1α expression in OSCC and the effect of HIF-1α-targeting miRNAs on the progression and metastatic potential of OSCC. We analyzed public databases to explore which miRNAs target HIF-1α expression. In addition, the expression of proteins involved in the cell cycle, proliferation, and apoptosis in HSC-2 cells was analyzed after miRNA-126 mimic treatment. Furthermore, to investigate the effect of miRNA-126 on the proliferation and invasion ability of OSCC cells, 5-ethynyl-2′-deoxyuridine and Transwell assays were performed. The activities of MMP-2 and MMP-9 were evaluated via gelatin zymography. Our results showed that miRNA-126, which targets HIF-1α, enhances OSCC cell proliferation by regulating the cell cycle and reinforces the cell mobility of OSCC via HIF-1α expression. These findings suggest that miRNA-126 may be a novel marker for OSCC treatment and the development of new tools for patients with OSCC.

Non-keratinizing squamous cell carcinoma (NKSCC) is a rare malignancy of the nose and paranasal sinuses which is characterized by a unique anastomosing ribbon-like growth pattern with absent of limited maturation and keratinization. NKSCC accounts for 10-27% of sinonasal squamous cell carcinomas and some of the NKSCCs are reported to be associated with high risk-HPV infection. Advanced lesion can involve the oral cavity with oral symptoms of palatal bulging, surface ulceration mimicking salivary gland tumors. Herein, we report a case of NKSCC of a 46-year old male, which clinically presented as a bulging mass on the mid palate and mimicked a palatal salivary gland tumor. We reviewed the clinical and histopathological considerations required for differential diagnosis of sinonasal carcinoma involving the oral cavity.

Autophagy is an evolutionarily well-conserved cellular homeostasis program that responds to various cellular stresses and degrades unnecessary or harmful intracellular materials in lysosomes. Accumulating evidence has shown that autophagy dysfunction often results in various human pathophysiological conditions, including metabolic disorders, cancers, and neurodegenerative diseases. The discovery of an autophagy machinery protein network has revealed underlying molecular mechanisms of autophagy, and advances in the understanding of its regulatory mechanism have provided novel therapeutic targets for treating human diseases. Recently, reports have emerged on the involvement of autophagy in oral squamous cell carcinoma (OSCC). Although the role of autophagy in cancer therapy is controversial, the beneficial use of the induction of autophagic cell death in OSCC has drawn significant attention. In this review, the types of autophagy, mechanism of autophagosome biogenesis, and modulating molecules and therapeutic candidates affecting the induction of autophagic cell death in OSCC are briefly described.

Worldwide, oral cancer accounts for 2%–4% of all cancer cases. It is estimated that more of 90% of all oral neoplasms are oral squamous cell carcinoma (OSCC). The aims of this study were to evaluate follow-up outcomes in patients with OSCC invading the mandibular body bone who underwent primary radical resection and reconstructive surgery by fibular free flap or CAD-CAM T-mesh with pathological study on two cases. In this article, two cases of mandibular reconstruction in patients with OSCC invading the mandibular body bone are reported. A 68-year-old male patient visited the authors’ clinic with pain on the left mandibular region. After wide excision and segmental mandibulectomy on the mandibular OSCC, a enterocutaneous fibular free flap from right leg was used to cover the intraoral mucosal defect. The other 51-year-old female patient visited the authors’ clinic with pain on the right mandibular region. After wide excision and segmental mandibulectomy on the mandibular OSCC, reconstruction was done with a reconstruction plate and a fibula free flap from right leg. Unfortunately, fibular free flap was lost due to infection of the flap at post-operative 1month, secondary reconstruction using a custom-made type T-mesh and iliac PCBM was done to repair on the mandibular defect after four years postoperatively. The customized CAD-CAM T-mesh was made prior to the operation according to mirror image of remained jaw. Patients with OSCC invading the mandibular body bone are required an accurate segmental mandibulectomy immediate reconstructive surgery with various methods and followed by adjuvant radiation with or without chemotherapy in order to improve the quality of life through the restoration of the oral function and esthetics after surgery. Postoperative CCRT was determined according to the final pathologic findings such as lymph node metastasis and main lesion free margin safety, and this has an essential relationship in the prognosis of postoperative recurrence. We reviewed reliable treatment options on two patients of OSCC in mandible with pathologic findings.Worldwide, oral cancer accounts for 2%–4% of all cancer cases. It is estimated that more of 90% of all oral neoplasms are oral squamous cell carcinoma (OSCC). The aims of this study were to evaluate follow-up outcomes in patients with OSCC invading the mandibular body bone who underwent primary radical resection and reconstructive surgery by fibular free flap or CAD-CAM T-mesh with pathological study on two cases. In this article, two cases of mandibular reconstruction in patients with OSCC invading the mandibular body bone are reported. A 68-year-old male patient visited the authors’ clinic with pain on the left mandibular region. After wide excision and segmental mandibulectomy on the mandibular OSCC, a enterocutaneous fibular free flap from right leg was used to cover the intraoral mucosal defect. The other 51-year-old female patient visited the authors’ clinic with pain on the right mandibular region. After wide excision and segmental mandibulectomy on the mandibular OSCC, reconstruction was done with a reconstruction plate and a fibula free flap from right leg. Unfortunately, fibular free flap was lost due to infection of the flap at post-operative 1month, secondary reconstruction using a custom-made type T-mesh and iliac PCBM was done to repair on the mandibular defect after four years postoperatively. The customized CAD-CAM T-mesh was made prior to the operation according to mirror image of remained jaw. Patients with OSCC invading the mandibular body bone are required an accurate segmental mandibulectomy immediate reconstructive surgery with various methods and followed by adjuvant radiation with or without chemotherapy in order to improve the quality of life through the restoration of the oral function and esthetics after surgery. Postoperative CCRT was determined according to the final pathologic findings such as lymph node metastasis and main lesion free margin safety, and this has an essential relationship in the prognosis of postoperative recurrence. We reviewed reliable treatment options on two patients of OSCC in mandible with pathologic findings.

Parosteal osteosarcoma, a subtype of juxtacortical osteosarcoma, has a better prognosis compared to central osteosarcoma with a relatively low risk for recurrence and metastasis. Rarely, it can arise synchronously with other malignant tumors. Synchronous malignancies are defined as the occurrence of a second primary malignancy within 6 months of the appearance of the first malignancy. Here in, we introduce a 64-year-old woman who visited the Department of Oral & Maxillofacial Surgery, Yonsei University Dental Hospital with a 2 year history of a whitish verrucous lesion on the palate. She presented an exophytic mass on mandible during the following visits. Histopathologic evaluation revealed a synchronous parosteal osteosarcoma and squamous cell on right mandible and a precancerous verrucous leukoplakia on the palate.

Resveratrol has been reported to exert anticancer activity via modulation of multiple pathways and genes. In this study, we examined the effect of resveratrol on YD-10B human oral squamous cell carcinoma cells and its molecular mechanisms of action. We found that resveratrol inhibited the proliferation of YD-10B cells in a dose- and timedependent manner. The suppressive effect of resveratrol was accompanied by a reduction in Bmi-1 gene expression. We observed that silencing the Bmi-1 gene by small interfering RNA effectively downregulated the levels of GLUT1 mRNA and protein, which were also repressed by resveratrol. Bmi-1 silencing increased the number of YD-10B cells in S-phase arrest by approximately 2.3-fold compared with the control. In conclusion, the results of the present study demonstrate, for the first time, that resveratrol suppresses Bmi-1-mediated GLUT1 expression in human oral squamous cell carcinoma cells and suggest that the specific molecular targeting of Bmi-1 and/or GLUT1 expression can be combined with a chemotherapeutic strategy to improve the response of oral cancer cells to resveratrol.

To accurately determine the resection margin for maxillary cancer, it is important to closely examine the extent of tumor infiltration into the maxilla, nasal cavity, maxillary sinus, palate, and surrounding tissues. Various methods have been described for the resection of maxillary tumors, such as alveolectomy, partial maxillectomy, subtotal maxillectomy, total maxillectomy, and extended maxillectomy. The objective of this study was to introduce external carotid artery (ECA) ligation on the ipsilateral side, a perioperative bleeding control method with fewer complications. Incidence of major bleeding during maxillectomy is a rare but potentially life-threatening complication. Cases of temporary bleeding from an internal maxillary artery or other sites can be stopped, packed, and compressed. However, bleeding control is eventually achieved by ligation of the ECA or selective embolization. Herein, we report the case of a 60-year-old male with squamous cell carcinoma of the right maxilla, which was eventually treated with subtotal maxillectomy along with an elective ECA ligation for intraoperative bleeding control. The procedure produced no preoperative or postoperative bleeding. ECA ligation is a simple, effective, safe, and (at the operator’s discretion) recommended method of perioperative bleeding control during maxillectomy.

Perineural invasion (PNI) is the underestimated metastatic pathway and has been widely recognized as a negative prognostic factor in many human cancers. L1CAM is one of members of the immunoglobulin-like cell adhesion molecule (CAM) family, which play a role in neural development. Moreover, a new role of L1CAM outside the nervous system has been revealed. Overexpression of L1CAM was involved in the tumor progression and LN metastasis in various malignancies. In the present study, presence of PNI and L1CAM expression were examined to define their prognostic values in OSCC. In addition, association of L1CAM expression with presence of PNI was assessed to define the value as a candidate molecule supporting the diagnosis of PNI. We found that presence of PNI significantly correlated with LN metastasis and advanced clinical stage. L1CAM expression also significantly correlated with differentiation, lymph node metastasis, advanced clinical stage, as well as presence of PNI. Our results suggest that L1CAM seems to play a role in tumor progression, possibly through the PNI-related mechanism and could be a molecular marker for supporting the presence of PNI and predicting clinical outcome in OSCC.

Bilobalide isolated from the leaves of Ginkgo biloba has several pharmacological activities such as neuroprotective, anti-inflammatory, and anticonvulsant. However, the effect of bilobalide on cancer has not been clearly established. The main purpose of this study was to investigate the effect of bilobalide on cell growth and apoptosis induction in FaDu human pharyngeal squamous cell carcinoma. This was examined by 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide assay, nuclear 4′,6-diamidino-2-phenylindole dihydrochloride staining, DNA fragmentation analysis, and immunoblotting. Bilobalide inhibited the growth of FaDu cells in dose- and time-dependent manners. Treatment with bilobalide resulted in nuclear condensation and DNA fragmentation in FaDu cells. Furthermore, it promoted the proteolytic cleavage of procaspase-3/-7/-8/-9 with increase in the amount of cleaved caspase-3/-7/-8/-9. Bilobalide-induced apoptosis in FaDu cells was mediated by the expression of Fas and the activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting revealed that the antiapoptotic mitochondrial protein Bcl-2 was downregulated, but the proapoptotic protein Bax was upregulated by bilobalide in FaDu cells. Bilobalide significantly increased Bax/Bcl-2 ratio. These results suggest that bilobalide inhibits cell proliferation and induces apoptosis in FaDu human pharyngeal squamous cell carcinoma via both the death receptor-mediated extrinsic apoptotic pathway and the mitochondrial-mediated intrinsic apoptotic pathway.

Basaloid squamous cell carcinoma (BSCC) is a rare and aggressive variant of squamous cell carcinoma arising in various anatomical sites. This article describes a case history of BSCC of the floor of mouth with mandibular involvement, and further discusses the appropriate management of such case with reference to the literature review. A 52-year-old male patient was referred to our clinic from another university hospital. Segmental mandibulectomy with supraomohyoid neck dissection and mandible reconstruction with left fibular free flap under general anesthesia was performed, followed by radiotherapy. Histopathological examination on the tumor lesion revealed features of squamous cell carcinoma with comedo-type necrosis. A diagnosis of BSCC was given by the oral pathology specialist. Basaloid squamous cell carcinoma (BSCC) is a biphasic variant of SCC with both basaloid and squamous cell histology. A recent report showed that there is no significant difference in the prognosis. Due to the lack of accumulated research, close follow-up and continuous research are deemed necessary. Treatment that focuses on the stage of the tumor is appropriate. A periodic follow-up observation is also very important due to the occurrence of distant metastasis to the lungs.

Tannic acid (TA) is a water-soluble polyphenol compound found in various herbal plants. We investigated the chemopreventive effects of TA on FaDu hypopharyngeal squamous carcinoma cells. In an 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay, TA showed dose-dependent cytotoxicity with a half maximal inhibitory concentration (IC50) of 50 μM. Cell cycle analysis and immunofluorescence imaging demonstrated that under lowdose (25 μM) treatment, FaDu cells were arrested in G2/M phase, and as the dose of TA was increased, apoptosis was induced with the increase of cell population at sub-G1 phase. The expressions of various cyclins, including cyclin D1 and cyclin-dependent kinases (CDK-1 and CDK-2), were down-regulated at low doses of TA, whereas apoptotic effectors such as cleaved caspase 3, cleaved caspase 7, and poly (ADP-ribose) polymerase (PARP) were expressed in a dose-dependent manner in Western blotting. In addition, TA-induced apoptosis of FaDu cells might be mediated by the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway, with the upregulation of p-AKT/p-PKB (phosphorylated protein kinase B) and p-ERK. Overall, our data support the hypothesis that TA is a potential candidate agent for the treatment of hypopharyngeal cancer.

Oral squamous cell carcinoma (OSCC) is the most common oral malignancy and an increasing global public health problem. OSCC frequently invades the jaw bone. OSCC-induced bone invasion has a significant impact on tumor stage, treatment selection, patient outcome, and quality of life. A number of studies have shown that osteoclastmediated bone resorption is a major step in the progression of bone invasion by OSCC; however, the molecular mechanisms involved in OSCC bone invasion are not yet clear. In this review, we present the clinical types of OSCC bone invasion and summarize the role of key molecules, including proteases, cytokines, and growth factors, in the sequential process of bone invasion. A better understanding of bone invasion will facilitate the discovery of molecular targets for early detection and treatment of OSCC bone invasion.

It is well known that lymph node metastasis is a major prognostic factor in patients with oral squamous cell carcinoma (OSCC). 30-40% of patients with OSCC have already undergone regional metastasis at diagnosis. The survival rate of patients with metastasis is reduced by more than 50%. Therefore, prevention and early detection of metastasis are very important to increase the survival rate of patients. Many investigators have studied the molecular mechanism of metastasis and tried to develop the molecules to inhibit any step of metastatic cascade. Among those molecules, an interest in the metastasis suppressor gene has been increasing. Expression of metastasis suppressor KiSS-1 has shown to be significantly related to poor clinical outcome and worse survival rate of patient in various malignancies of different organs. In addition, our previous study in OSCC also revealed that downregulation of KiSS-1 expression correlated with the presence of cervical lymph node metastasis, one part of tumor progression. Therefore, further investigation was needed to identify the molecular function of KiSS-1 using OSCC cell line and to evaluate the possibility of KiSS-1 as a new therapeutic target.

Recently chronic inflammation is focused on the association with cancer progression and acquisition of aggressive biologic behaviors, such as invasion, metastasis, and resistance to chemotherapeutic reagents. Due to the close vicinity within oral cavity, oral cancer may be intimately associated with chronic periodontitis. The present study was done to observe the effect of chronic periodontitis on oral cancer cells by utilizing P. gingivalis infection, a major pathogen in chronic periodontitis. We analyzed and compared the mRNA expression levels of epithelial-mesenchymal transition (EMT) markers in non-infected and P. gingivalis-infected oral cancer cells. Eighty-six genes, which are well known as EMT markers, were analyzed using commercially available EMT microarray plates, performed in triplicate. Among the 86 genes, the expression of 26 was increased (≥ 2 fold) by P. gingivalis, whereas that of 7 genes was decreased (≥ 2 fold). Our study suggests that P. gingivalis infection evokes significant changes in EMT-related genes. Further observations on molecular mechanisms underlying these changes may help to clarify the role of chronic periodontitis on cancer progression and to develop more efficient preventive and therapeutic modalities for oral cancer. (182 words)

Autophagy is recently receiving the spotlight as the development strategy for promising anticancer drugs. In particular, the majority of anticancer drugs originating from natural products are known to induce autophagy. Saururus chinensis has been used for treating various inflammatory diseases. Recent research has revealed that the extract of Saururus chinensis possess cytotoxicity for various types of human cancer cells. However, the exact action mechanism of Saururus chinensis extract for oral squamous cell carcinoma (OSCC) has not been studied yet. Therefore, the authors of this research aim to study the effect of methanol extract of S. chinensis (MESC) on OSCC cells. To observe the cell proliferation inhibitory effect of MESC on HSC3 cells, the authors conducted the trypan blue exclusion assay. Also, the action mechanism of MESC was studied by conducting the cell cycle analysis, acidic vesicular organelle (AVO) staining and flow cytometry analysis, monodansylcadaverine (MDC) staining, propidium iodide staining, and Western blotting on MESC-treated HSC3 cells. When HSC3 cells were treated in MESC, the cell proliferation was suppressed in time-dependent and dose-dependent manners. Also, the number of sub-G1 arrested cells increased in a dose-dependent manner. MDC punctate and AVO puncta significantly increased respectively. Western blot analysis demonstrated the expression of autophagy-related proteins increased, but apoptotic proteins were not observed. Also, the pAkt protein was reduced, while the p-p38 protein and pERK protein increased. According to our results, MESC induced autophagy and accompanied changes in the cell cycle in HSC3 cells. Also, the alteration in Akt, ERK, and p38 pathways were confirmed. This result suggested the possibility of MESC as the new promising adjuvant for treating OSCC patients.