Human Oral Squamous Cancer Cells Research Articles

Betanin alleviates inflammation and ameliorates apoptosis on human oral squamous cancer cells SCC131 and SCC4 through the NF-κB/PI3K/Akt signaling pathway.

Oral squamous cell carcinoma (OSCC) is the prime kind of human malignancy with a great mortality ratio and a deprived prognosis due to its high level of relapse and metastasis. Recently reported is that betanin exerts a preventive role and cytotoxic activity on numerous cancer cells. Betanin comprises the betalain group, which is a highly bioavailable antioxidant. However, the precise molecular actions of betanin in the OSCC cells are yet to be elucidated. It may be the first report on the antiproliferative and apoptotic molecular mechanisms of betanin on OSCC. The current study intended to explore the betanin activity and its underlying mechanisms on SCC131 and SCC4 cells. The cytotoxicity assay, intracellular ROS, MMP, cell apoptosis, and inflammatory mediators of betanin activity on SCC131 and SCC4 cells were evaluated by MTT assay, DCFH-DA, Rh-123, AO/EB, DAPI, PI, analysis of western blot and RT-PCR. The upshots indicated that betanin restrains the SCC131 cells proliferation, MMP and inflammation, whereas induces apoptosis via the enhanced ROS level of SCC131 and SCC4 cells in a dose-dependent mode. Also, betanin-treated OSCC cells reduce inflammatory and apoptotic signaling pathways. The above-mentioned results exposed that betanin can inhibit cell viability, MMP, inflammation and enhanced apoptosis via the expression of NF-κB/PI3K/Akt pathways. Thus, our current findings provided an innovative vision into the protective effect against OSCC.

Chitinase 3-Like-1 Expression Is Upregulated Under Inflammatory Conditions in Human Oral Epithelial Cells.

Chitinase 3-like-1 (CHI3L1), also known as YKL-40, is a partially secreted glycoprotein and is involved in inflammatory disorders, including inflammatory bowel diseases. CHI3L1 is known to play a role in biological responses such as cell proliferation, tissue remodeling, and inflammation. CHI3L1 forms an immune complex (known as a Chitosome complex) with IL-13 receptor alpha 2 (IL-13 Rα2) and transmembrane protein 219 (TMEM219) to activate the MAPK/ERK and PKB/AKT signaling pathways. The objective of this study is to investigate how the expressions of CHI3L1 and a Chitosome complex in human oral cavity epithelial cells are linked with intraoral inflammatory diseases. CHI3L1 and Chitosome complex mRNA expressions were analyzed using human oral squamous cancer cell lines, HSC3 and HSC4 cells. Signaling activation in HSC4 cells was analyzed by using the western blot technique. Immunohistological analysis was performed using surgical samples obtained from patients with benign oral cavity tumors and cysts. Increased expression of CHI3L1 was observed in both HSC3 and HSC4 cells after TNFα stimulation. The expression of Chitosome complex factors increased as CHI3L1 levels increased, resulting in the activation of a downstream signaling pathway. Among the intraoral tissues, the epithelial cells from inflammatory lesions, but not benign tumors, were found to be intensively stained with the anti-CHI3L1 antibody. It was indicated that the formation of a Chitosome complex is induced during inflammation, leading to the activation of signaling pathways.

Xanthoxyletin Inhibits Proliferation of Human Oral Squamous Carcinoma Cells and Induces Apoptosis, Autophagy, and Cell Cycle Arrest by Modulation of the MEK/ERK Signaling Pathway.

BackgroundThis study aimed to investigate the effects of xanthoxyletin, a plant-derived coumarin, on human oral squamous cancer cells in vitro and in mouse xenografts in vivo.Materia/MethodsThe study included SCC-1 human oral cancer cells and EBTr normal embryonic bovine tracheal epithelial cells, which were treated with 0 μM, 5 μM, 10 μM, and 20 μM of xanthoxyletin for 24 hours. The MTT assay assessed cell viability, and autophagy was detected by electron microscopy. Cell apoptosis was investigated using 4′,6-diamidino-2-phenylindole (DAPI), annexin V, and propidium iodide (PI) fluorescence flow cytometry, which was also used to investigate the cell cycle. Protein expression was measured by Western blot. Mouse xenografts were used for the in vivo evaluation of the effects of xanthoxyletin.ResultsXanthoxyletin significantly inhibited the proliferation of oral cancer cells (IC50, 10–30 μM) with lower cytotoxicity for normal cells. Xanthoxyletin treatment was associated with G2/M arrest of the cell cycle and with increased apoptosis and autophagy of SCC-1 cells. Apoptosis and autophagy induced by xanthoxyletin were also associated with changes in expression of the apoptosis-associated proteins, Bax and Bcl-2, and the autophagy-associated proteins, LC3I, LC3II, Beclin 1, p62, and VSp34. Xanthoxyletin inhibited the expression of components of the signaling cascade of the MEK/ERK pathway in the SCC-1 oral cancer cells. The in vivo effects of xanthoxyletin showed inhibition of growth of mouse xenografts.ConclusionsXanthoxyletin inhibited the proliferation of human oral squamous carcinoma cells and induced apoptosis, autophagy, and cell cycle arrest by modulation of the MEK/ERK signaling pathway.

Inhibition of aqueous extracts of Solanum nigrum (AESN) on oral cancer through regulation of mitochondrial fission

The present study is designed to investigate the anti-oral cancer properties of Solanum nigrum on oral squamous cell carcinoma. S. nigrum is a Chinese herb used for suppression of various cancers. However, the inhibition of S. nigrum on oral cancer is unclear. Therefore, human oral squamous cancer cells (SCC)-4 were used to evaluate the effect of aqueous extracts of S. nigrum (AESN) on cancer cell proliferation, cell cycle, mitochondrial function and apoptosis. The SCC-4 cells were treated by AESN to evaluate the inhibition of cell proliferation and mitochondrial function in vitro. Our results suggested that AESN markedly increased reactive oxygen species production. AESN also promoted caspase-9 and caspase-3 activation and subsequent triggering of the mitochondrial apoptotic pathway. The inhibition of glucose uptake was alleviated mediated by a dose-dependent manner in SCC-4 cells with AESN treatment for 24 h, resulting in mitochondrial fission. These results suggested that AESN has potential to be used as a functional food in adjuvant chemotherapy for treating human oral cancer by suppression of mitochondrial function.

MiR-376c-3p regulates the proliferation, invasion, migration, cell cycle and apoptosis of human oral squamous cancer cells by suppressing HOXB7.

To test the influence of miR-376c-3p on the proliferation, invasion, migration, cell cycle and apoptosis of human oral squamous cancer cells (OSCC) and the relevant mechanism. We applied qRT-PCR and Western blot to compare the expression level of miR-376c-3p and HOXB7 in SCC-4, SCC-9, SCC-15, SCC-25 OSCC cell lines and 49 paired OSCC and normal oral epithelial tissue specimens were included in our present study. Also we analyzed the relative relationship of expression level between miR-376c-3p and HOXB7 in cancer tissues. Luciferase assay was used to confirm the target relationship between miR-376c-3p and HOXB7. Besides, MTT, Transwell, wound healing, colony formation and flow cytometer experiments were applied to evaluate the proliferation, cell viability, apoptosis, invasion and migration of transfected OSCC. MiR-376c-3p was down-regulated while HOXB7 was up-regulated in OSCC tissues and cells than the normal ones. MiR-376c-3p directly targeted HOXB7 and reduced the expression of HOXB7. Overexpression of miR-376c-3p attenuated proliferation of SCC-9, SCC-15, SCC-24 and SCC-25 cells. Moreover, miR-376c-3p suppressed proliferation, viability, migration and invasion and induced G1/G0 arrest and cell apoptosis of SCC-25 cells. Besides, overexpression of HOXB7 efficiently abrogates these influences caused by overexpression of miR-376c-3p. MiR-376c-3p suppresses the fission, proliferation, migration and invasion and induces cell apoptosis of OSCC via targeting HOXB7.

Nanoparticle Delivered VEGF-A siRNA Enhances Photodynamic Therapy for Head and Neck Cancer Treatment

Photodynamic therapy (PDT) is believed to promote hypoxic conditions to tumor cells leading to overexpression of angiogenic markers such as vascular endothelial growth factor (VEGF). In this study, PDT was combined with lipid-calcium-phosphate nanoparticles (LCP NPs) to deliver VEGF-A small interfering RNA (siVEGF-A) to human head and neck squamous cell carcinoma (HNSCC) xenograft models. VEGF-A were significantly decreased for groups treated with siVEGF-A in human oral squamous cancer cell (HOSCC), SCC4 and SAS models. Cleaved caspase-3 and in situ TdT-mediated dUTP nick-end labeling assay showed more apoptotic cells and reduced Ki-67 expression for treated groups compared to phosphate buffered saline (PBS) group. Indeed, the combined therapy showed significant tumor volume decrease to ~70 and ~120% in SCC4 and SAS models as compared with untreated PBS group, respectively. In vivo toxicity study suggests no toxicity of such LCP NP delivered siVEGF-A. In summary, results suggest that PDT combined with targeted VEGF-A gene therapy could be a potential therapeutic modality to achieve enhanced therapeutic outcome for HNSCC.

BubR1 Acts as a Promoter in Cellular Motility of Human Oral Squamous Cancer Cells through Regulating MMP-2 and MMP-9.

BubR1 is a critical component of spindle assembly checkpoint, ensuring proper chromatin segregation during mitosis. Recent studies showed that BubR1 was overexpressed in many cancer cells, including oral squamous cell carcinomas (OSCC). However, the effect of BubR1 on metastasis of OSCC remains unclear. This study aimed to unravel the role of BubR1 in the progression of OSCC and confirm the expression of BubR1 in a panel of malignant OSCC cell lines with different invasive abilities. The results of quantitative real-time PCR showed that the mRNA level of BubR1 was markedly increased in four OSCC cell lines, Ca9-22, HSC3, SCC9 and Cal-27 cells, compared to two normal cells, normal human oral keratinocytes (HOK) and human gingival fibroblasts (HGF). Moreover, the expression of BubR1 in these four OSCC cell lines was positively correlated with their motility. Immunofluorescence revealed that BubR1 was mostly localized in the cytosol of human gingival carcinoma Ca9-22 cells. BubR1 knockdown significantly decreased cellular invasion but slightly affect cellular proliferation on both Ca9-22 and Cal-27 cells. Consistently, the activities of metastasis-associated metalloproteinases MMP-2 and MMP-9 were attenuated in BubR1 knockdown Ca9-22 cells, suggesting the role of BubR1 in promotion of OSCC migration. Our present study defines an alternative pathway in promoting metastasis of OSCC cells, and the expression of BubR1 could be a prognostic index in OSCC patients.

Multifunctional effects of honokiol as an anti-inflammatory and anti-cancer drug in human oral squamous cancer cells and xenograft

The aim of this study was to investigate anti-inflammatory and anti-cancer effects of honokiol (HK) in two oral squamous cancer cell carcinoma (OSCC) cell lines, HN22 and HSC4, through the regulation of inducible nitric oxide synthase (iNOS) and endoplasmic reticulum resident protein 44 (ERp44). Griess assay, zymography, and quantitative PCR were performed to study iNOS expression and subsequent nitric oxide (NO) production in OSCC cell lines. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis was used to elucidate the proteins associated with ER stress and cellular cytotoxic response induced by HK. Pull-down assay and molecular modeling were performed to better understand how HK interacts with ERp44. In vitro and in vivo experiments in which ERp44 expression was knocked down were performed to better understand the effects of ERp44 on a cellular level and anti-cancer effects of HK. Expression levels of iNOS and subsequent NO secretion were reduced in OSCC cell lines treated with HK. ERp44 was significantly decreased in OSCC cell lines by HK treatment. HK directly bound to ERp44, and ERp44 knock-down significantly inhibited oral cancer cell proliferation and colony formation. Moreover, HK treatment effectively inhibited tumor growth and ERp44 levels in BALB/c nude mice bearing HN22 cell xenografts. Our findings suggest that HK inhibited inflammation and induced apoptosis by suppressing both iNOS/NO and ERp44 expression in HN22 and HSC4 cells and xenograft tumors, and thus could be a potent anti-inflammatory and anti-cancer drug candidate for human oral cancer treatment.

Lipopeptides extract from Bacillus amyloliquefaciens induce human oral squamous cancer cell death.

A lipopeptide extract of Bacillus amyloliquefaciens BACY1 (BLE) was found to induce cell death in human oral squamous cell carcinoma (OSCC) cell lines, SCC4 and SCC25, in this study. The results of MTT assay showed that BLE inhibited OSCC cell proliferation in a dose-dependent manner. BLE was also effective in increasing the sub-G1 phases. Furthermore, when membrane damage in SCC4 cells treated with BLE was monitored by LDH assay, release of LDH was significantly increased. The protein and mRNA levels of pro-apoptotic Bax, and caspase-3 were up-regulated by BLE. Taken together, these results suggest that BLE induces apoptosis and then inhibits the cell proliferation of human OSCC cells.

Apoptotic effects of 7,8-dihydroxyflavone in human oral squamous cancer cells through suppression of Sp1.

7,8-Dihydroxyflavone (7,8-DHF) is a member of the flavonoid family and has recently been identified as a brain-derived neurotrophic factor mimetic that selectively activates tropomyosin-receptor kinase B with high affinity. The antioxidant and anticancer effects of 7,8-DHF have been reported. However, the pharmacological mechanisms of 7,8-DHF in oral cancer are unclear. Thus, we investigated the mechanisms of the antiproliferative action of 7,8-DHF on HN22 and HSC4 oral squamous cell carcinoma cell lines. We demonstrated that 7,8-DHF decreased cell growth and induced apoptosis in the HN22 and HSC4 cells through regulation of specificity protein 1 (Sp1) using the MTS assay, DAPI staining, Annexin V, propidium iodide staining, reverse transcription-polymerase chain reaction, immunocytochemistry, pull-down assay and western blot analysis. The results showed that the Sp1 protein bound with 7,8-DHF in the HN22 and HSC4 cells. Taken together, the results suggest that 7,8-DHF could modulate Sp1 transactivation and induce apoptotic cell death by regulating the cell cycle and suppressing antiapoptotic proteins. Furthermore, 7,8-DHF may be valuable for cancer prevention and better clinical outcomes.

Discovery of Sulfonamidebenzamides as Selective Apoptotic CHOP Pathway Activators of the Unfolded Protein Response.

Cellular proteins that fail to fold properly result in inactive or disfunctional proteins that can have toxic functions. The unfolded protein response (UPR) is a two-tiered cellular mechanism initiated by eukaryotic cells that have accumulated misfolded proteins within the endoplasmic reticulum (ER). An adaptive pathway facilitates the clearance of the undesired proteins; however, if overwhelmed, cells trigger apoptosis by upregulating transcription factors such as C/EBP-homologous protein (CHOP). A high throughput screen was performed directed at identifying compounds that selectively upregulate the apoptotic CHOP pathway while avoiding adaptive signaling cascades, resulting in a sulfonamidebenzamide chemotype that was optimized. These efforts produced a potent and selective CHOP inducer (AC50 = 0.8 μM; XBP1 > 80 μM), which was efficacious in both mouse embryonic fibroblast cells and a human oral squamous cell cancer cell line, and demonstrated antiproliferative effects for multiple cancer cell lines in the NCI-60 panel.

A surprising cross-species conservation in the genomic landscape of mouse and human oral cancer identifies a transcriptional signature predicting metastatic disease.

Improved understanding of the molecular basis underlying oral squamous cell carcinoma (OSCC) aggressive growth has significant clinical implications. Herein, cross-species genomic comparison of carcinogen-induced murine and human OSCCs with indolent or metastatic growth yielded results with surprising translational relevance. Murine OSCC cell lines were subjected to next-generation sequencing (NGS) to define their mutational landscape, to define novel candidate cancer genes, and to assess for parallels with known drivers in human OSCC. Expression arrays identified a mouse metastasis signature, and we assessed its representation in four independent human datasets comprising 324 patients using weighted voting and gene set enrichment analysis. Kaplan-Meier analysis and multivariate Cox proportional hazards modeling were used to stratify outcomes. A quantitative real-time PCR assay based on the mouse signature coupled to a machine-learning algorithm was developed and used to stratify an independent set of 31 patients with respect to metastatic lymphadenopathy. NGS revealed conservation of human driver pathway mutations in mouse OSCC, including in Trp53, mitogen-activated protein kinase, phosphoinositide 3-kinase, NOTCH, JAK/STAT, and Fat1-4. Moreover, comparative analysis between The Cancer Genome Atlas and mouse samples defined AKAP9, MED12L, and MYH6 as novel putative cancer genes. Expression analysis identified a transcriptional signature predicting aggressiveness and clinical outcomes, which were validated in four independent human OSCC datasets. Finally, we harnessed the translational potential of this signature by creating a clinically feasible assay that stratified patients with OSCC with a 93.5% accuracy. These data demonstrate surprising cross-species genomic conservation that has translational relevance for human oral squamous cell cancer. Clin Cancer Res; 20(11); 2873-84. ©2014 AACR.

Migratory activity and invadosome formation in invasive oral cancer cells

The objective of this study is to explore the relationship between migration ability and invadosome organization in human oral squamous cancer cells. Wound healing assay, immunofluorescence, Western blotting, and matrix metalloproteinase zymogen gel assay were utilized to investigate the phenotype changes of three oral squamous cancer cells (OC3, OC3-I5, and OC3-IV2). Among these three cell lines, selective subpopulations of OC3, OC3-I5, and OC3-IV2 have high migratory ability compared to OC3 in a wound healing assay. Moreover, immunofluorescence showed that formation of actin dots and paxillin rings in OC3 was less than in OC3-I5 and OC3-IV2. Minor differences of other adhesion molecules and matrix metalloproteinase activity have also been observed. Enhanced cell migration ability and increased invadosomes have been detected in both in vitro selection cell line OC3-I5 and in vivo selection cell line OC3-IV2, suggesting that there may be a correlation between migration activity and invadosome formation in invasive oral cancer cells. Therefore, it would be interesting for us to continue discovering more invadosome components and evaluate whether they play any role in the regulation of the invasion ability of oral cancer cells.

Small proline-rich protein-1B is overexpressed in human oral squamous cell cancer stem-like cells and is related to their growth through activation of MAP kinase signal

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are considered to be essential for tumor maintenance, recurrence and metastasis. Therefore, eradication of CSCs/CICs is essential to cure cancers. However, the molecular mechanisms of CSCs/CICs are still elusive. In this study, we investigated the molecular mechanism of the cell growth of oral CSCs/CICs. Oral CSCs/CICs were isolated as aldehyde dehydrogenase 1 bright (ALDH1br) cells by the ALDEFLUOR assay. Small proline-rich protein-1B (SPRR1B) gene was shown to be overexpressed in ALDH1br cells by a cDNA microarray and RT-PCR. SPRR1B was shown to have a role in cell growth and maintenance of ALDH1br cells by SPRR1B overexpression and knockdown experiments. To elucidate the molecular mechanism by which SPRR1B regulates cell growth, further cDNA microarray analysis was performed using SPRR1B-overexpressed cells and cells with SPRR1B knocked down by siRNA. Expression of the tumor suppressor gene Ras association domain family member 4 (RASSF4) was found to be suppressed in SPRR1B-overexpressed cells. On the other hand, the expression of RASSF4 was enhanced in cells in which SPRR1B expression was knocked down by SPRR1B-specific siRNA. RASSF4 has an RA (Ras association) domain, and we thus hypothesized that RASSF4 modulates the MAP kinase signal downstream of the Ras signal. MAP kinase signal was activated in SPRR1B-overexpressed cells, whereas the signal was suppressed in SPRR1B knocked down cells. Taken together, the results indicate that the expression of SPRR1B is upregulated in oral CSCs/CICs and that SPRR1B has a role in cell growth by suppression of RASSF4.

Change in Nicotine-Induced VEGF, PGE2 AND COX-2 Expression Following COX Inhibition in Human Oral Squamous Cancer

Cigarette smoke has been documented to be related to the development of cancer. However, the exact mechanism for the carcinogenic action of cigarette smoke is still unknown. Nicotine is recognized to be the major compound in cigarette smoke and has been suggested to play a role in oral cancer via a cyclooxygenase (COX)/ prostaglandin-dependent pathway. This study was designed to evaluate the action of nicotine in the oral cancer cell and to further examine whether COX-2 is responsible for expression of tumor-associated angiogenic vascular endothelial growth factor (VEGF) in vitro. Viability of human oral squamous cancer cells (BHY) was measured using MTT assay. Protein expression was determined by Western blot and immunoassay kits. We found that exposure of BHY cells to nicotine (200 µg/mL for 6 hours) resulted in 2.9-fold induction of COX-2 expression as well as a 4-fold increase in VEGF levels compared with a control group. Pretreatment with celecoxib inhibited nicotine-induced change in the expression of VEGF and COX-2. The results suggest that stimulation of COX-2 and VEGF expression can contribute as important factors in the tumorigenic action of nicotine in oral cancer progression. This effect can be blocked by celecoxib, suggesting an interaction of nicotine and COX-2 pathways.

Abstract 1494: Characterization of a novel pro-tumorigenic TGF-β RII mutation from oral squamous cell carcinoma

Abstract TGF-β signaling plays various roles in tumor progression. Tumor suppressive TGF- β signaling is involved in early steps of carcinogenesis through loss of function which leads to deregulated proliferation. On the contrary, TGF- β signaling could be pro-tumorigenic in later stages of carcinogenesis by promoting epithelial-mesenchymal transition (EMT). Most of the reported TGF- β receptor-II mutations were loss of tumor suppressor function mutations and no pro-tumorigenic TGF- β receptor-II mutation has been identified in human tumors. This study aimed to analyze a novel mutation of TGF- β receptor-II found in metastatic lymph node of oral squamous cell carcinoma. This mutant converts amino acid 227 from I to T and amino acid 236 from N to D of TGF- β receptor-II. Promoter assay using 3TP-lux reporter showed that 227/236 double mutation significantly increased both basal and TGF- β-induced luciferase activity as compared to wild type in DR-26, TGF- β receptor-II-defective mink lung epithelial cells. Stable expression of 227/236 mutant enhanced migration and invasion as well as cell growth of HSC-2 cells, human oral squamous cancer cell line whose TGF- β signaling is not growth inhibitory. In 227/236 mutant transfectant, E-cadherin expression is reduced whereas snail expression has not been changed significantly. In orthotopic xenograft model to monitor the tumor growth, 227/236 mutant transfectant formed significantly larger tumors as compared to wild type transfectant. But, unexpectedly, there was no difference in the expression pattern of involucrin and E-cadherin in these tumor tissues, suggesting that this mutation did not affect EMT in vivo model system. In the study we present a novel gain-of-function mutation of TGF- β receptor II, which increased TGF- β signaling and thereby induced tumor growth without affecting EMT in HSC-2 oral squamous cancer cells. This work was supported by a grant from the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic research promotion fund KRF-2005-005-J05901). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1494.

S‐allylcysteine modulates the expression of E‐cadherin and inhibits the malignant progression of human oral cancer

Oral cancer is a prevalent type of cancer in the Asian countries. Several studies indicated that garlic extracts such as diallyl disulfide (DADS) and diallyl trisulfide (DATS) have anti‐cancer effects. However, the inhibitory effects of water soluble garlic extracts, S‐allylcysteine (SAC), on the tumor malignancy of oral cancer have not been studied well yet. Thus, the purpose of this study was to investigate the inhibitory effects of SAC on the proliferation and progression of human oral squamous cancer CAL‐27 cells.In the present study, we demonstrated that SAC dose dependently inhibited the growth of human oral squamous cancer cells. Our results showed that SAC induced the expression of E‐cadherin adhesion molecule. Immunocytochemical staining result also revealed that SAC could restore the distribution of E‐cadherin molecule on cell membrane. We further demonstrated that SAC stabilized the adherent junction complex of E‐cadherin/β‐catenin in oral cancer cells. Treatment of MAPK/MEK specific inhibitor, PD098059, could upregulate the expression of E‐cadherin molecule. Furthermore, SAC significantly inhibited the activation of MAPK/ERK signaling pathway. These findings were associated with the down regulation of Slug repressor protein.In conclusion, our results indicated that SAC effectively inhibited the proliferation, upregulated the expression of E‐cadherin molecule, and stabilized the E‐cadherin/β‐catenin adherent junction complex in human oral squamous cancer cells. The mechanism of action was in part through the suppression of MAPK/ERK signaling pathway and downregulation of Slug repressor protein.

S-Allylcysteine modulates the expression of E-cadherin and inhibits the malignant progression of human oral cancer

Oral cancer is a prevalent type of cancer in Asian countries. Several studies indicated that garlic extracts such as diallyl disulfide (DADS) and diallyl trisulfide (DATS) have anticancer effects. However, the inhibitory effects of water soluble garlic extracts, S-allylcysteine (SAC), on the malignant progression of oral cancer have not been studied well yet. Thus, the purpose of this study was to investigate the inhibitory effects of SAC on the proliferation and progression of human oral squamous cancer CAL-27 cells. In the present study, we demonstrated that SAC dose dependently inhibited the growth of human oral squamous cancer cells. Our results showed that SAC induced the expression of E-cadherin adhesion molecule. Immunocytochemical staining result also revealed that SAC could restore the distribution of E-cadherin molecule on cell membrane. We further demonstrated that SAC stabilized the adherent junction complex of E-cadherin/β-catenin in oral cancer cells. Treatment with the MAPK/MEK specific inhibitor, PD098059, could up-regulate the expression of E-cadherin molecule. Furthermore, SAC significantly inhibited the activation of MAPK/ERK signaling pathway. These findings were associated with the down-regulation of the SLUG repressor protein. In conclusion, our results indicated that SAC effectively inhibited the proliferation, up-regulated the expression of E-cadherin molecule and stabilized the E-cadherin/β-catenin adherent junction complex in human oral squamous cancer cells. The mechanism of action was in part through the suppression of MAPK/ERK signaling pathway and down-regulation of the SLUG repressor protein.

Transgenic B7-H3 therapy induces tumor-specific immune response in human oral squamous cell cancer: an in vitro study

Tumors may present antigens to T cells but lack costimulatory signals which are necessary to initialize an effective immunologic response. This study aimed to develop a tumor cell-based cancer vaccine by genetically modifying oral squamous cell cancer (OSCC) cell line Tca8113 with human B7-H3 immunoglobulin, and to evaluate its efficacy in enhancing the tumor-specific immune response. Human B7-H3 gene was extracted from isolated T lymphocytes of healthy volunteers. Tumor cell vaccine TCV-hB7-H3 and mock control were prepared by transfecting Tca8113 cells with B7-H3 or mock vector. After being stimulated with TCV-hB7-H3 or mock control, the proliferation, IFN-mu expression, and cytotoxicity of the T cells were assessed. The Tca8113 cells transfected with human B7-H3 significantly enhanced the proliferation, IFN-mu expression, and cytotoxicity of the T cells. Genetically modified OSCC cells encoding B7-H3 enhance the induction of tumor specific immune response.

Ornithine Decarboxylase Antizyme Upregulates DNA-Dependent Protein Kinase and Enhances the Nonhomologous End-Joining Repair of DNA Double-Strand Breaks in Human Oral Cancer Cells

Ornithine decarboxylase (ODC) antizyme targets ODC for ubiquitin-independent proteosome degradation, thereby inhibiting polyamine synthesis. It has been shown to regulate DNA methylation and has tumor suppressor activity. Increasing evidence suggested that antizyme may also have ODC-independent functions. Here, we report that antizyme plays a role in DNA double-strand break repairs. A zinc-inducible human antizyme gene expression vector was transfected into UM1 human oral squamous cancer cells that do not express endogenous antizyme. The resultant upregulated genes were screened by cDNA arrays and confirmed by quantitative real-time polymerase chain reaction. DNA-dependent protein kinase including its catalytic subunit DNA-PKcs and regulatory subunit Ku70, two key proteins of the DNA damage repair machinery, was significantly upregulated after ectopic expression of antizyme. Consistently, we found that UM1 cells are sensitive to gamma irradiation and deficient in DNA damage repairs, as shown by radio-sensitivity and Comet assays. Ectopic expression of antizyme increased radio-resistance of UM1 cells and restored their capacity of DNA damage repairs to the level of UM2 cells that have an identical genetic background but express endogenous antizyme. Plasmid end-joining assays confirmed that antizyme enhances the ability of UM1 cells to repair DNA double-strand breaks by the nonhomologous end-joining pathway.