• International Journal of Oral Biology
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• v.46 no.4
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• pp.176-183
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• 2021

Oral squamous cell carcinoma (OSCC) metastasis is characterized by distant metastasis and local recurrence. Combined chemotherapy with cisplatin and 5-fluorouracil is routinely used to treat patients with OSCC, and the combined use of gefitinib with cytotoxic drugs has been reported to enhance the sensitivity of cancer cells in vitro. However, the development of drug resistance because of prolonged chemotherapy is inevitable, leading to a poor prognosis. Therefore, understanding alterations in signaling pathways and gene expression is crucial for overcoming the development of drug resistance. However, the altered characterization of Ca²⁺ signaling in drug-resistant OSCC cells remains unclear. In this study, we investigated alterations in intracellular Ca²⁺ ([Ca²⁺]_i) mobilization upon the development of gefitinib resistance in human tongue squamous carcinoma cell line (HSC)-3 and HSC-4 using ratiometric analysis. This study demonstrated the presence of altered epidermal growth factor- and purinergic agonist-mediated [Ca²⁺]_i mobilization in gefitinib-resistant OSCC cells. Moreover, Ca²⁺ content in the endoplasmic reticulum, store-operated calcium entry, and lysosomal Ca²⁺ release through the transient receptor potential mucolipin 1, were confirmed to be significantly reduced upon the development of apoptosis resistance. Consistent with [Ca²⁺]_i mobilization, we identified modified expression levels of Ca²⁺ signaling-related genes in gefitinib-resistant cells. Taken together, we propose that the regulation of [Ca²⁺]_i mobilization and related gene expression can be a new strategy to overcome drug resistance in patients with cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.74-82
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• 2009

In order to make successful oral cancer treatment, we need to understand about tumor biology and effective chemotherapeutic agents. To achieve these studies, it is necessary to develope a proper in-vivo model. Therefore the author will make try to develop more improved animal model of more applicable in various method of cancer study. In this study, the author induced in-vivo tumorigenesis in nude mice by $YD-10B_{mod}$ cell line used by YD-10B cell line originated from oral tongue squamous cell carcinoma and observed tumor formations and invasiveness of surrounding tissue, and found some results as follows : 1. The experimental group($YD-10B_{mod}$, subcutaneous injection) produced tumors 13 out of 15 mice, while the control group produced none of 5 mice. 2. The inoculation of $1{\times}10^6$cells/mouse produced tumors 3 out of 5 mice and inoculation of $1{\times}10^7$cells/mouse, $2{\times}10^7$cells/mouse produced tumors in every 5 mice. 3. In the histopathologic studies, the inoculation of $1{\times}10^6$cells/mouse group showed the characteristic features of well-differentiated squamous cell carcinoma and demarcated expansile growth, while the inoculation of $1{\times}10^7$cells/mouse, $2{\times}10^7$cells/mouse group showed the expansile growth with partial central necrosis and invasive growth to surrounding fat & connective tissue. These findings suggest that atopic xenograft of $YD-10B_{mod}$ cell line in nude mice has a improved productivity of tumors, produced tumors showed the characteristics feature of human tumor and invasive growth to surrounding tissue in histopathologic appearance. These atopic nude mouse model of tongue carcinoma might assist in studying oral cancer biology and effective choice of chemotherapeutic agents.

• International Journal of Oral Biology
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• v.40 no.1
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• pp.51-61
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• 2015

Shikonin, a major ingredient in the traditional Chinese herb Lithospermumerythrorhizon, exhibits multiple biological functions including antimicrobial, anti-inflammatory, and antitumor effects. It has recently been reported that shikonin displays antitumor properties in many cancers. This study was aimed to investigate whether shikonin could inhibit oral squamous carcinoma cell (OSCC) growth via mechanisms of apoptosis and cell cycle arrest. The effects of shikonin on the viability and growth of OSCC cell line, SCC25 cells were assessed by MTT assay and clonogenic assays, respectively. Hoechst staining and DNA electrophoresis indicated that the shikonin-treated SCC25 cells were undergoing apoptosis. Western blotting, immunocytochemistry, confocal microscopy, flow cytometry, MMP activity, and proteasome activity also supported the finding that shikonin induces apoptosis. Shikonin treatment of SCC25 cells resulted in a time- and dose-dependent decrease in cell viability, inhibition of cell growth, and increase in apoptotic cell death. The treated SCC25 cells showed several lines of apoptotic manifestation as follows: nuclear condensation; DNA fragmentation; reduced MMP and proteasome activity; decrease in DNA contents; release of cytochrome c into cytosol; translocation of AIF and DFF40 (CAD) onto the nuclei; a significant shift in Bax/Bcl-2 ratio; and activation of caspase-9, -7, -6, and -3, as well as PARP, lamin A/C, and DFF45 (ICAD). Shikonin treatment also resulted in down-regulation of the G1 cell cycle-related proteins and up-regulation of $p27^{KIP1}$. Taken together, our present findings demonstrate that shikonin strongly inhibits cell proliferation by modulating the expression of the G1 cell cycle-related proteins, and that it induces apoptosis via the proteasome, mitochondria, and caspase cascades in SCC25 cells.

• Journal of Korean society of Dental Hygiene
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• v.14 no.4
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• pp.601-608
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• 2014

Objectives : The purpose of the study is to examine the apoptotic effects of Pseudomonas aeruginosa exotoxin A(PEA) in squamous cell carcinoma(SCC) 25 cells. Methods : Cell growth reduction and apoptosis induced by PEA were confirmed by WST-1 assay, Hoechst 33258 staining, flow cytometry analysis, and Western blot assay. Results : The PEA treatment decreased the cell viability in a dose and time dependent manner: control; $100{\pm}0^e$(p<0.01), 0.1875 nM; $87{\pm}4.36^d$(p<0.01), 0.375 nM; $82{\pm}0.58^d$(p<0.01), 0.75 nM; $72{\pm}1.67^c$(p<0.01), 1.5 nM; $51{\pm}1.53^{bc}$(p<0.01), 7.5 nM; $31{\pm}1.20^{ab}$(p<0.01), 15 nM; $26{\pm}0.67^a$(p<0.01), control; $100{\pm}0^a$(p<0.05), 24 h; $51{\pm}1.53^b$(p<0.05), 48 h; $16{\pm}0.5^c$(p<0.05), 72 h; $12{\pm}1.67^d$%(p<0.05). The PEA was observed on SCC 25 cells with the half maximal inhibitory concentration(IC50) value of 1.5 nM at 24 hours. The PEA treated SCC 25 cells demonstrated several types of apoptotic indications, such as nuclear condensation, the increase of sub G1, and the cleavage of PARP-1 and DFF 45. Conclusions : PEA showed anti-cancer activity against SCC 25 cells via apoptosis. PEA may potentially contribute to human oral cancer treatment.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.261-276
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• 2009

Lactacystin, a microbial natural product synthesized by Streptomyces, has been commonly used as a selective proteasome inhibitor in many studies. Proteasome inhibitors is known to be preventing the proliferation of cancer cells in vivo as well as in vitro. Furthermore, proteasome inhibitors, as single or combined with other anticancer agents, are suggested as a new class of potential anticancer agents. This study was undertaken to examine in vitro effects of cytotoxicity and growth inhibition, and the molecular mechanism underlying induction of apoptosis in SCC25 human tongue sqaumous cell carcinoma cell line treated with lactacystin. The viability of SCC25 cells, human normal keratinocytes (HaCaT cells) and human gingiva fibroblasts (HGF-1 cells), and the growth inhibition of SCC25 cells were assessed by MTT assay and clonogenic assay respectively. The hoechst staining, hemacolor staining and TUNEL staining were conducted to observe SCC25 cells undergoing apoptosis. SCC25 cells were treated with lactacystin, and Western blotting, immunocytochemistry, confocal microscopy, FAScan flow cytometry, MMP activity, and proteasome activity were performed. Lactacystin treatment of SCC25 cells resulted in a time- and does-dependent decrease of cell viability and a does-dependent inhibition of cell growth, and induced apoptotic cell death. Interestingly, lactacytin remarkably revealed cytotoxicity in SCC25 cells but not normal cells. And tested SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA contents, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, the up-regulation of Bax, and the activation of caspase-7, caspase-3, PARP, lamin A/C and DFF45 (ICAD). Flow cytometric analysis revealed that lactacystin resulted in G1 arrest in cell cycle progression which was associated with up-regulation in the protein expression of CDK inhibitors, $p21^{WAF1/CIP1}$ and $p27^{KIP1}$. We presented data indicating that lactacystin induces G1 cell cycle arrest and apoptois via proteasome, mitochondria and caspase pathway in SCC25 cells. Therefore our data provide the possibility that lactacystin could be as a novel therapeutic strategy for human tongue squamous cell carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8351-8359
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• 2014

Background: Recent epidemiological data have implicated human papilloma virus (HPV) infection in the pathogenesis of head and neck cancers, especially oropharyngeal cancers. Although, HPV has been detected in varied amounts in persons with oral dysplasia, leukoplakias and malignancies, its involvement in oral tongue carcinogenesis remains ambiguous. Materials and Methods: HPV DNA prevalence was assessed by PCR with formalin fixed paraffin embedded sections (n=167) of oral tongue squamous cell carcinoma patients and the physical status of the HPV16 DNA was assessed by qPCR. Immunohistochemistry was conducted for p16 evaluation. Results: We found the HPV prevalence in tongue cancers to be 51.2%, HPV 16 being present in 85.2% of the positive cases. A notable finding was a very poor concordance between HPV 16 DNA and p16 IHC findings (kappa<0.2). Further molecular classification of patients based on HPV16 DNA prevalence and p16 overexpression showed that patients with tumours showing p16 overexpression had increased hazard of death (HR=2.395; p=0.005) and disease recurrence (HR=2.581; p=0.002) irrespective of their HPV 16 DNA status. Conclusions: Our study has brought out several key facets which can potentially redefine our understanding of tongue cancer tumorigenesis. It has emphatically shown p16 overexpression to be a single important prognostic variable in defining a high risk group and depicting a poorer prognosis, thus highlighting the need for its routine assessment in tongue cancers. Another significant finding was a very poor concordance between p16 expression and HPV infection suggesting that p16 expression should possibly not be used as a surrogate marker for HPV infection in tongue cancers. Interestingly, the prognostic significance of p16 overexpression is different from that reported in oropharyngeal cancers. The mechanism of HPV independent p16 over expression in oral tongue cancers is possibly a distinct entity and needs to be further studied.

• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.221-233
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• 2013

Bile acids are polar derivatives of cholesterol essential for the absorption of dietary lipids and regulate the transcription of genes that control cholesterol homeostasis. Recently it have been identified the synthetic chenodeoxycholic acid (CDCA) derivatives HS-1200 and cisplatin showed apoptisis-inducing activity on various cancer cells in vivo and in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with HS-1200 and cisplatin on human tongue squamous cell carcinoma cells (SCC25 cells). To investigate whether the co-treatment with HS-1200 and cisplatin compared to each single treatment efficiently reduces the viability of SCC25 cells, MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis DNA hypoploidy. Westen blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. In this study, co-treatment with HS-1200 and cisplatin on SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, reduction of MMP and proteasome activity, the increase of Bax and the decrease of Bcl-2, decrease of DNA content, the release of cytochrome c into cytosol, translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD) whereas each single treated SCC25 cells did not show these patterns. Although the single treatment of $25{\mu}M$ HS-1200 and $4{\mu}g/ml$ cisplatin for 24 h did not induce apoptosis, the co-treatment of these reagents prominently induced apoptosis. Therefore our data provide the possibility that the combination therapy with HS-1200 and cisplatin could be considered as a novel therapeutic strategy for human squamous cell carcinoma.

• Journal of Oral Medicine and Pain
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• v.36 no.3
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• pp.147-160
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• 2011

Eugenol (4-allyl-2-methoxyphenol) is a natural phenolic constituent extensively used in dentistry as a component of zinc oxide eugenol cement and is applied to the mouth environment. Chios gum mastic (CGM) is a resinous exudate obtained from the stem and the main leaves of Pistacia lenticulus tree native to Mediterranean areas. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with a natural product, CGM and natural phenolic compound, eugenol on SCC25 human tongue squamous cell carcinoma cell line. To investigate whether the co-treatment with eugenol and CGM compared to each single treatment efficiently reduces the viability of SCC25 cells, MTT assay was conducted. Induction and augmentation of apoptosis were confirmed by Hoechst staining, TUNEL staining and DNA hypoploidy. Westen blot analysis and immunofluorescent staining were performed to study the alterations of the expression level and the translocation of apoptosis-related proteins in co-treatment. In this study, co-treatment of with eugenol and CGM on SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, the increase and decrease of Bax and Bcl-2, decrease of DNA content, the release of cytochrome c into cytosol, translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-3, caspase-6 caspase-7, caspase-9, PARP, Lamin A/C and DFF45 (ICAD) whereas each single treated SCC25 cells did not show or very slightly these patterns. Although the single treatment of 40 ${\mu}g$/ml CGM and 0.5 mM eugenol for 24 h did not induce apoptosis, the co-treatment of these reagents prominently induced apoptosis. Therefore our data provide the possibility that combination therapy with CGM and eugenol could be considered as a novel therapeutic strategy for human oral squamous cell carcinoma.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.550-555
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• 2011

Chromosomal loss of heterozygosity (LOH) is a common mechanism for the inactivation of tumor suppressor genes in human epithelial cancers. LOH patterns can be generated through allelotyping using polymorphic microsatellite markers; however, owing to the limited number of available microsatellite markers and the requirement for large amounts of DNA, only a modest number of microsatellite markers can be screened. Hybridization to single nucleotide polymorphism (SNP) arrays using Affymetarix GeneChip Mapping 10 K 2.0 Array is an efficient method to detect genome-wide cancer LOH. We determined the presence of LOH in oral SCCs using these arrays. DNA was extracted from tissue samples obtained from 10 patients with tongue SCCs who presented at the Hospital of Tokyo Dental College. We examined the presence of LOH in 3 of the 10 patients using these arrays. At the locus that had LOH, we examined the presence of LOH using microsatellite markers. LOH analysis using Affymetarix GeneChip Mapping 10K Array showed LOH in all patients at the 1q31.1. The LOH regions were detected and demarcated by the copy number 1 with the series of three SNP probes. LOH analysis of 1q31.1 using microsatellite markers (D1S1189, D1S2151, D1S2595) showed LOH in all 10 patients (100). Our data may suggest that a putative tumor suppressor gene is located at the 1q31.1 region. Inactivation of such a gene may play a role in tongue tumorigenesis.

• Journal of Life Science
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• v.28 no.8
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• pp.945-954
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• 2018

Omega-3 polyunsaturated fatty acids (${\omega}3$-fatty acid) have been found to possess anticancer properties in a variety of cancer cell lines and animal models, but their effects in human tongue squamous cell carcinomas (SCCs) remain unclear. This study was designed to examine the effect of ${\omega}3$-fatty acid desaturase (fat-1) gene expression on invasion and tumorigenicity in human tongue SCC cells and the molecular mechanism of its action. Docosahexaenoic acid (DHA) treatment inhibited in vitro invasion in a dose-dependent manner. In zymography, matrix metalloproteinase-9 (MMP-9) and Matrix metallopeptidase-2 (MMP-2) activities were reduced, and MMP-9 and MMP-2 promoter activities were inhibited by the DHA treatment. In addition, cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) promoter reporter activities were inhibited in SCC-4 and SCC-9 cells after the DHA treatment. To investigate the effect of a high level of endogenous ${\omega}3$ fatty acids, a stable SCC-9 cell line expressing the ${\omega}3$-desaturase gene (fSCC-9sc) was generated. The growth rate and colony-forming capacity of fSCC-9sc were remarkably decreased as compared with those of fSCC-9cc. Likewise, the tumor size and volume of fSCC-9sc implanted into nude mice were significantly inhibited, with increases in the cell death index. Furthermore, a transwell chamber invasion assay showed a reduction in cell invasion of the fSCC-9sc lines when compared with that of the fSCC-9cc line. These findings suggested that fat-1 gene expression inhibited tumorigenicity, as well as invasion in human tongue SCC cells. Thus, utilization of ${\omega}3$ fatty acids may represent a promising therapeutic approach for chemoprevention and the treatment of human tongue SCCs.