Qilan preparation inhibits proliferation and induces apoptosis by down-regulating microRNA-21 in human Tca8113 tongue squamous cell carcinoma cells.

OBJECTIVE: The aim of this study was to examine the antitumor effects of Qilan preparation on oral squamous cell carcinoma (OSCC) and to investigate its underlying mechanisms of action. METHODS: Cell proliferation, cell cycle distribution and apoptosis were examined using cell counting kit-8 (CCK8) and flow cytometry (FCM). The expression of PTEN and PDCD4 were determined by western blot. Changes in miR-21 levels were quantified using TaqMan stem-loop real-time PCR. After miR-21 was transiently transfected into Tca8113 cells using Lipofectamine®3000, cell proliferation, apoptosis and miR-21 and PDCD4 expression levels were measured. RESULTS: Qilan preparation inhibited Tca8113 cell growth in a dose- and time-dependent manner by inducing apoptosis and cell cycle arrest in S-phase, decreasing miR-21 levels and increasing PTEN and PDCD4 expression. MiR-21 overexpression reversed the Qilan preparation-induced suppression of cell proliferation and induction of apoptosis while also blocking the increase in PDCD4. CONCLUSIONS: Our study revealed, for the first time, the ability of Qilan preparation to suppress TSCC cell growth and elucidated that Qilan preparation elicits its anti-cancer actions either the miR-21/PDCD4 or PTEN pathway.

Tongue squamous cell carcinoma resists hyperthermia treatment by promoting Id-1 expression mediated EMT.

Epithelial-mesenchymal transition (EMT) is a key initial step in the recurrence and metastasis of tongue squamous cell carcinoma (TSCC). Hyperthermia (HT) may reduce the rate of postoperative recurrence and distant metastasis by reversing the process of EMT of tumor cells, but the molecular mechanism is unclear. This study aims to investigate the role of inhibitor of differentiation/DNA binding-1 (Id-1) in HT mediated reversal of EMT of TSCC cells, and to provide a new approach for the treatment of TSCC using therapeutic gene targeting. After the combination of RNA interference with Id-1 and HT, the morphology of TSCC cells changed from spindle-like to pebble-like, and the arrangement of cells changed from loose and disorderly to compact and orderly. The silencing of Id-1 gene enhances the efficacy of HT by affecting the expression of EMT markers in TSCC cells. This study suggests that the Id-1 gene in TSCC cells can regulate transforming growth factor-beta 1, thereby affecting the expression of EMT markers, to achieve the effect of reducing HT.

EGCG inhibits growth of tumoral lesions on lip and tongue of K-Ras transgenic mice through the Notch pathway.

Epigallocatechin-3-gallate (EGCG), the main active ingredient of green tea, exhibits low toxic side effect and versatile bioactivities, and its anti-cancer effect has been extensively studied. Most of the studies used cancer cell lines and xenograft models. However, whether EGCG can prevent tumor onset after cancer-associated mutations occur is still controversial. In the present study, Krt14-cre/ERT-Kras transgenic mice were developed and the expression of K-RasG12D was induced by tamoxifen. Two weeks after induction, the K-Ras mutant mice developed exophytic tumoral lesions on the lips and tongues, with significant activation of Notch signaling pathway. Administration of EGCG effectively delayed the time of appearance, decreased the size and weight of tumoral lesions, relieved heterotypic hyperplasia of tumoral lesions, and prolonged the life of the mice. The Notch signaling pathway was significantly inhibited by EGCG in the tumoral lesions. Furthermore, EGCG significantly induced cell apoptosis and inhibited the proliferation of tongue cancer cells by blocking the activation of Notch signaling pathway. Taken together, these results indicate EGCG as an effective chemotherapeutic agent for tongue cancer by targeting Notch pathway.

Cytotoxicity mechanisms of plumbagin in drug-resistant tongue squamous cell carcinoma.

OBJECTIVES: To evaluate the inhibitory effect and mechanism of plumbagin (PLB) against drug-resistant tongue squamous cell carcinoma (TSCC), and whether its antitumour effect is not affected by tumour drug resistance. METHODS: TSCC sensitive CAL27 cells and drug-resistant CAL27/RE cells were used to study the cytotoxicity and mechanism of PLB in vitro, including CCK-8 analysis, colony formation, DAPI staining, flow cytometry assay, transmission electron microscopy, western blotting assay, autophagy, apoptosis and ROS fluorescent probes. BALB/c nude mice xenograft models were used to study the growth inhibitory effect of PLB in vivo. KEY FINDINGS: The results showed that the cell viability and proliferation inhibition and apoptosis induction abilities of PLB on drug-resistant cells were more obvious than that on sensitive cells. And PLB induced protective autophagy in TSCC cells. Mechanistically, PLB induced apoptosis and autophagy by generating reactive oxygen species to mediate JNK and AKT/mTOR pathways. Finally, the growth inhibitory effect of PLB against drug-resistant TSCC was also confirmed in vivo. CONCLUSIONS: PLB will be a promising anticancer agent to overcome drug-resistant TSCC without being affected by its drug resistance properties.

YY1-mediated PTEN dephosphorylation antagonizes IR-induced DNA repair contributing to tongue squamous cell carcinoma radiosensitization.

Ionizing radiation (IR) confers a survival advantage in tongue squamous cell carcinoma (TSCC), however, IR resistance limits its efficacy. Although Yin Yang 1 (YY1) has been reported to play a role in genotoxic drug resistance by accelerating DNA repair, its role in TSCC radioresistance remains unclear. In this study, we examined YY1 mRNA and protein expression in human tongue cancer samples using qRT-PCR and western blotting, respectively. DNA array data identified YY1 mRNA expression in IR sensitivity or resistance cell lines and tissues. Tongue carcinoma primary cells and CAL27 cells with YY1 stably overexpressed or knocked-down were exposed to IR and evaluated for cell proliferation and apoptosis by CCK8-assay and caspase-3 assay, respectively. We also examined DNA damage- or repair-related indicators, such as YY1, p-H2AX, nuclear PTEN, p-PTEN, and Rad51 through Western blot analysis. Additionally, we explored the mechanism of IR-induced PTEN nuclear translocation by introducing a series of PTEN phosphorylation site mutations and co-IP assay. We observed that YY1 mRNA and protein are highly expressed in TSCC tissues, which was correlated with worse overall survival. Moreover, higher expression of YY1 and Rad51 was observed in radioresistant cells and tissues, overexpression of YY1 led to IR resistance in TSCC cells, whereas YY1 knockdown sensitized TSCC cells to IR. The underlying mechanism showed that the overexpression of YY1 upregulated nuclear PTEN and Rad51 expression, which is essential for DNA repair. IR upregulated YY1, nuclear PTEN, and Rad51; thus, knockdown of YY1 completely blocked IR-induced upregulation of nuclear PTEN/Rad51. IR upregulated PTEN phosphorylation, and mutation of the phosphorylation site of Ser380 nearly completely blocked IR-induced PTEN nuclear translocation. Furthermore, the phosphatase PP2A negatively regulated pS380-PTEN, and knockdown of YY1 completely blocked IR-induced pS380-PTEN through PP2A. In conclusion, knockdown of YY1 enhanced TSCC radiosensitivity through PP2A-mediated dephosphorylation of PTEN Ser380; thus, antagonizing the IR-induced nuclear PTEN/Rad51 axis and targeting YY1 may reverse IR resistance in TSCC.

Safflower polysaccharide inhibits the development of tongue squamous cell carcinoma.

BACKGROUND: Safflower polysaccharide (SPS) is one of the most important active components of safflower (Carthamus tinctorius L.), which has been confirmed to have the immune-regulatory function and antitumor effect. This study aimed to explore the effects of safflower polysaccharide (SPS) on tongue squamous cell carcinoma (TSCC). METHODS: HN-6 cells were treated with 5 µg/mL cisplatin and various concentrations of SPS (0, 0.02, 0.04, 0.08, 0.16, 0.32, 0.64, and 1.28 mg/mL), and cell proliferation was measured. After treatment with 5 µg/mL cisplatin and 0.64 mg/mL SPS, the induction of apoptosis and the protein and mRNA expression of Bax, Bcl-2, COX-2, and cleaved caspase-3 in HN-6 cells were quantified. In addition, HN-6 cells were implanted into mice to establish an in vivo tumor xenograft model. Animals were randomly assigned to three groups: SPS treatment, cisplatin treatment, and the model group (no treatment). The body weight, tumor volume, and tumor weight were measured, and the expression of the above molecules was determined. RESULTS: SPS treatment (0.02-0.64 mg/mL) for 24-72 h inhibited HN-6 cell proliferation. In addition, 0.64 mg/mL SFP markedly induced apoptosis in HN-6 cells and arrested the cell cycle at the G0/G1 phase. Compared with the control group, the expression of Bcl-2 and COX-2 was markedly reduced by SPS treatment, whereas the expression of Bax and cleaved caspase-3 was increased. Moreover, SPS significantly inhibited the growth of the tumor xenograft, with similar changes in the expression of Bcl-2, COX-2, Bax, and cleaved caspase-3 in the tumor xenograft to the in vitro analysis. CONCLUSIONS: Our results indicated that SPS may inhibit TSCC development through regulation of Bcl-2, COX-2, Bax, and cleaved caspase-3 expression.

High-dose ascorbic acid induces carcinostatic effects through hydrogen peroxide and superoxide anion radical generation-induced cell death and growth arrest in human tongue carcinoma cells.

High-dose ascorbic acid (AsA) treatment, known as pharmacological AsA, has been shown to exert carcinostatic effects in many types of cancer cells and in vivo tumour models. Although pharmacological AsA has potential as a complementary and alternative medicine for anticancer treatment, its effects on human tongue carcinoma have not yet been elucidated. In this study, we investigated the effect of AsA treatment on human tongue carcinoma HSC-4 cells compared with non-tumourigenic tongue epithelial dysplastic oral keratinocyte (DOK) cells. Our results show that treatment with 1 and 3 mM of AsA for 60 min preferentially inhibits the growth of human tongue carcinoma HSC-4 over DOK cells. Furthermore, AsA-induced effects were accompanied by increased intracellular oxidative stress and were repressed by treatment with a hydrogen peroxide (H2O2) scavenger catalase and a superoxide anion radical (O2-) scavenger, tempol. Time-lapse observation and thymidine analog EdU incorporation revealed that AsA treatment induces not only cell death but also suppression of DNA synthesis and cell growth. Moreover, the growth arrest was accompanied by abnormal cellular morphologies whereby cells extended dendrite-like pseudopodia. Taken together, our results demonstrate that AsA treatment can induce carcinostatic effects through induction of cell death, growth arrest, and morphological changes mediated by H2O2 and O2- generation. These findings suggest that high-dose AsA treatment represents an effective treatment for tongue cancer as well as for other types of cancer cells.

Geraniol attenuates 4NQO-induced tongue carcinogenesis through downregulating the activation of NF-κB in rats.

Geraniol, an acyclic monoterpene found in lemon grass and aromatic herb oil, has been shown to exert antitumor and antioxidant activities against various cancer types. The objective of this study was to investigate the potential chemoprotective role of geraniol against 4-nitroquinoline-1-oxide (4NQO)-induced oral carcinogenesis in male Wistar rats and furthermore to study anti-inflammatory mechanisms of action through possible NF-κB signaling. 4NQO was administered to rats at the dose of 50 ppm through drinking water to induce tongue cancer in 20 weeks. 4NQO provoked inflammation by upregulating the expressions of the p65 subunit nuclear factor kappa-ß (NF-κB) in the nucleus, tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). Additionally, staining for immature and mature mast cells in cancer niche by toluidine blue staining and alcian blue-safranin staining showed more accumulation. Co-treatment of geraniol 200 mg/kg b.w. showed a significant decrease in the level of p65 NF-κB in the nucleus, and this might be due to the inhibition of NF-κB activation/translocation into nucleus, which was further confirmed by decreased immature and mature mast cell density and the expression of inflammatory downstream mediators such as TNF-α, IL-1ß, COX-2, and iNOS. Collectively, our results suggested that geraniol as a potential anti-inflammatory agent having the capability to obstruct 4NQO initiated NF-κB activation and modulated the expression of inflammatory mediators.

Cortactin is a prognostic marker for oral squamous cell carcinoma and its overexpression is involved in oral carcinogenesis.

EMS1 (chromosome eleven, band q13, mammary tumor and squamous cell carcinoma-associated gene 1) gene amplification and the concomitant cortactin overexpression have been reported to associate with poor prognosis and tumor metastasis. In this study, we examined cortactin expression by immunohistochemistry in human oral tumors and murine tongue tumors which were induced by the carcinogen 4-nitroquinoline 1-oxide (4-NQO). The immunostaining results show over- to moderate expression of cortactin in 85% (104/122) of oral squamous cell carcinoma (OSCC) tissues and in all 15 leukoplakia tissues examined. Further, statistical analysis indicates that cortactin overexpression appears to be a predictor for shorter survival and poorer prognosis in OSCC patients. In an animal model, cortactin is shown to upregulate in infiltrating squamous cell carcinoma, papilloma, and epithelia with squamous hyperplasia, indicating that cortactin induction is an early event during oral carcinogenesis. It is suggested that cortactin expression is mediated in the progression of pre-malignancy to papilloma, based on earlier cortactin induction in pre-malignancy preceding cyclin D1 in papilloma. In conclusion, cortactin overexpression is frequently observed in human OSCC and mouse tongue tumors. Thus, cortactin may have an important role in the development of oral tumors in human and mice. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 799-812, 2017.

Circadian Clock Gene Bmal1 Inhibits Tumorigenesis and Increases Paclitaxel Sensitivity in Tongue Squamous Cell Carcinoma.

Circadian clock genes regulate cancer development and chemotherapy susceptibility. Accordingly, chronotherapy based on circadian phenotypes might be applied to improve therapeutic efficacy. In this study, we investigated whether the circadian clock gene Bmal1 inhibited tumor development and increased paclitaxel sensitivity in tongue squamous cell carcinoma (TSCC). Bmal1 expression was downregulated and its rhythmic pattern of expression was affected in TSCC samples and cell lines. Ectopic Bmal1 inhibited cell proliferation, migration and invasion in vitro, and tumor growth in mouse xenograft models of TSCC. After exposure to paclitaxel, Bmal1-overexpressing cells displayed a relative increase in apoptosis and were more susceptible to paclitaxel treatment in vivo Mechanistic investigations suggested a regulatory connection between Bmal1, TERT, and the oncogenic transcriptional repressor EZH2 (enhancer of zeste homolog 2), the recruitment of which to the TERT promoter increased paclitaxel-induced apoptosis and cell growth inhibition. Clinically, paclitaxel efficacy correlated positively with Bmal1 expression levels in TSCC. Overall, our results identified Bmal1 as a novel tumor suppressor gene that elevates the sensitivity of cancer cells to paclitaxel, with potential implications as a chronotherapy timing biomarker in TSCC. Cancer Res; 77(2); 532-44. ©2016 AACR.

Antitumor and apoptosis-inducing effects of α-mangostin extracted from the pericarp of the mangosteen fruit (Garcinia mangostana L.)in YD-15 tongue mucoepidermoid carcinoma cells.

α-mangostin is a dietary xanthone which has been shown to have antioxidant, anti-allergic, antiviral, antibacterial, anti-inflammatory and anticancer effects in various types of human cancer cells. In the present study, we aimed to elucidate the molecular mechanisms responsible for the apoptosis-inducing effects of α-mangostin on YD-15 tongue mucoepidermoid carcinoma cells. The results from MTT assays revealed that cell proliferation significantly decreased in a dose-dependent manner in the cells treated with α-mangostin. DAPI staining illustrated that chromatin condensation in the cells treated with 15 µM α-mangostin was far greater than that in the untreated cells. Flow cytometric analysis indicated that α-mangostin suppressed YD-15 cell viability by inducing apoptosis and promoting cell cycle arrest in the sub-G1 phase. Western blot analysis of various signaling molecules revealed that α-mangostin targeted the extracellular signal­regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) signaling pathways through the inhibition of ERK1/2 and p38 phosphorylation in a dose­dependent manner. α-mangostin also increased the levels of Bax (pro-apoptotic), cleaved caspase-3, cleaved caspase-9 and cleaved-poly(ADP-ribose) polymerase (PARP), whereas the levels of the anti-apoptotic factors, Bcl-2 and c-myc, decreased in a dose-dependent manner. The anticancer effects of α-mangostin were also investigated in a tumor xenograft mouse model. The α-mangostin-treated nude mice bearing YD-15 tumor xenografts exhibited a significantly reduced tumor volume and tumor weight due to the potent promoting effects of α-mangostin on cancer cell apoptosis, as determined by TUNEL assay. Immunohistochemical analysis revealed that the level of cleaved caspase-3 increased, whereas the Ki-67, p-ERK1/2 and p-p38 levels decreased in the α-mangostin­treated mice. Taken together, the findings of our study indicate that α-mangostin induces the apoptosis of YD-15 tongue carcinoma cells through the ERK1/2 and p38 MAPK signaling pathways.

Ketorolac salt is a newly discovered DDX3 inhibitor to treat oral cancer.

DDX3 belongs to DEAD box RNA helicase family and is involved in the progression of several types of cancer. In this work, we employed a High Throughput Virtual screening approach to identify bioactive compounds against DDX3 from ZINC natural database. Ketorolac salt was selected based on its binding free energy less than or equals to -5 Kcal/mol with reference to existing synthetic DDX3 inhibitors and strong hydrogen bond interactions as similar to crystallized DDX3 protein (2I4I). The anti-cancer activity of Ketorolac salt against DDX3 was tested using oral squamous cell carcinoma (OSCC) cell lines. This compound significantly down regulated the expression of DDX3 in human OSCC line (H357) and the half maximal growth inhibitory concentration (IC50) of Ketorolac salt in H357 cell line is 2.6 µM. Ketorolac salt also inhibited the ATP hydrolysis by directly interacting with DDX3. More importantly, we observed decreased number of neoplastic tongue lesions and reduced lesion severity in Ketorolac salt treated groups in a carcinogen induced tongue tumor mouse model. Taken together, our result demonstrates that Ketorolac salt is a newly discovered bioactive compound against DDX3 and this compound can be used as an ideal drug candidate to treat DDX3 associated oral cancer.

Scutellariae radix induces apoptosis in chemoresistant SCC-25 human tongue squamous carcinoma cells.

Scutellariae radix is one of the most widely used anticancer herbal medicines in several Asian countries, including Korea, Japan, and China. Squamous cell carcinoma (SCC) is one of the most common head and neck carcinomas, which is highly invasive and metastatic, and can potentially develop chemoresistance. Therefore, new effective treatment methods are urgently needed. We determined the effects of Scutellariae radix on SCC-25 cells using the WST-1 assay, F-actin staining, flow cytometry analysis, immunofluorescence staining, and western blot analysis. Scutellariae radix treatment inhibited SCC-25 cell growth in a dose- and time-dependent manner, but it did not inhibit HaCaT (human keratinocyte) cell growth. Changes in cell morphology and disruption of filamentous (F)-actin organization were observed. Scutellariae radix-induced apoptosis as indicated by the translocation of cytochrome c and apoptosis-inducing factor (AIF) into the nucleus and cytosol. Scutellariae radix-induced an increase in cells with sub-G1 DNA content, and increased Bax, cleaved caspase-3, caspase-7, caspase-9, DNA fragmentation factor 45 (DFF 45), and poly(ADP-ribose) polymerase-1 (PARP-1) expression levels. Furthermore, increased expression of phosphorylated mitogen-activated protein kinase (MAPK)-related proteins was detected. The antitumor effect of Scutellariae radix was due to decreased cell proliferation, changes in cell morphology, and the activation of caspase and MAPK pathways. Taken together, the findings of this study highlight the anticancer activity of Scutellariae radix in chemoresistant SCC-25 oral squamous carcinoma cells.

Hyperthermia inhibited the migration of tongue squamous cell carcinoma through TWIST2.

BACKGROUND: Hyperthermia has been shown promising in the treatment of head and neck squamous cell carcinoma (HNSCC); however, the mechanism underlying hyperthermia reducing tumor metastasis is poorly elucidated. TWIST2, an important transcription factor of epithelial-mesenchymal transition (EMT), plays a critical role in the tumor progression and metastasis. The role of TWIST2 in tongue squamous cell carcinoma (TSCC) and its association with hyperthermia still have not been reported. METHOD: The correlations between TWIST2 expression and the clinical-pathologic characteristics of 89 patients with TSCC were evaluated by immunohistochemical staining. TSCC cell lines transfected with siRNA against TWIST2 were heated for 40 min at 42.5°C, and the migration capability of cells was examined by migration assay. Xenograft tumors in nude mice were treated by hyperthermia, and TWIST2 expression was measured. RESULTS: Our data showed that TWIST2 expression was associated with the metastasis of human TSCC. In Tca8113 and Cal-27 cells, TWIST2-siRNA treatment can reduce cell migration ability and has no effect on the cell proliferation and apoptosis. Hyperthermia can decrease the level of TWIST2 in TSCC and inhibit the migration of cells. CONCLUSIONS: This demonstrated that hyperthermia might decrease the migration of Tca8113 and Cal-27 cells by reducing TWIST2 expression. Altogether, these findings suggest an as yet undescribed link between TWIST2 and hyperthermia in TSCC.

In vitro anticancer effects of insect tea in TCA8113 cells.

BACKGROUND: Insect tea is widely used a traditional drink or traditional Chinese medicine in China. This study was conducted with an aim to determine the in vitro anticancer effect of Insect tea in cancer cells. MATERIALS AND METHODS: The anticancer effects of Insect tea were evaluated in human tongue carcinoma TCA8113 cells using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry analysis, nuclear staining with 4,6-diamidino-2-phenylindole (DAPI), reverse transcription-polymerase chain reaction (RT-PCR) analysis, and western bolt assay. RESULTS: At 200 µg/mL, Insect tea inhibited the growth of TCA8113 cells by 80.7%, which was higher than the inhibition caused by 100 µg/mL Insect tea but lower than that of 200 µg/mL green tea. Compared to the control cancer cells, Insect tea significantly (P<0.05) induced apoptosis as determined by DAPI staining and flow cytometry analysis results. Insect tea significantly induced apoptosis in cancer cells by upregulating BAX, CASP3, CASP9 and downregulating BCL2. Genes encoding nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were significantly downregulated by Insect tea, demonstrating its anti-inflammatory properties. Insect tea also exerted a great anti-metastasis effect on cancer cells as demonstrated by decreased expression of matrix metalloproteinase (MMP) genes and increased expression of tissue inhibitors of metalloproteinases (TIMPs). CONCLUSION: The results showed that Insect tea has good in vitro anticancer effects in TCA8113 cells, like green tea.

Induction of apoptotic death by curcumin in human tongue squamous cell carcinoma SCC-4 cells is mediated through endoplasmic reticulum stress and mitochondria-dependent pathways.

Curcumin from the rhizome of the Curcuma longa plant has been noted for its chemo-preventative and chemo-therapy activities, and it inhibits the growth of many types of human cancer cell lines. In this study, the mechanisms of cell death involved in curcumin-induced growth inhibition, including cell cycle arrest and induction of apoptosis in human tongue cancer SCC-4 cells, were investigated. Herein, we observed that curcumin inhibited cell growth of SCC-4 cells and induced cell death in a dose-dependent manner. Treatment of SCC-4 cells with curcumin caused a moderate and promoted the G(2) /M phase arrest, which was accompanied with decreases in cyclin B/CDK1 and CDC25C protein levels. Moreover, curcumin significantly induced apoptosis of SCC-4 cells with a decrease of the Bcl-2 level, reduction of mitochondrial membrane potential (ΔΨ(m) ), and promoted the active forms of caspase-3. Curcumin also promoted the releases of AIF and Endo G from the mitochondria in SCC-4 cells by using confocal laser microscope. Therefore, we suggest that curcumin induced apoptosis through a mitochondria-dependent pathway in SCC-4 cells. In addition, we also found that curcumin-induced apoptosis of SCC-4 cells was partly through endoplasmic reticulum stress. In conclusion, curcumin increased G(2) /M phase arrest and induced apoptosis through ER stress and mitochondria-dependent pathways in SCC-4 cells.

Hyaluronic acid-paclitaxel conjugate inhibits growth of human squamous cell carcinomas of the head and neck via a hyaluronic acid-mediated mechanism.

Chemotherapeutic regimens incorporating taxanes significantly improve outcomes for patients with squamous cell carcinomas of the head and neck (SCCHN). However, treatment with taxanes is limited by toxicities, including bone marrow suppression and peripheral neuropathies. We proposed that conjugating taxanes to targeting carrier molecules would increase antitumor efficacy and decrease toxicity. The cell surface proteoglycan, CD44, is expressed on most SCCHNs, and we hypothesized that it is an attractive candidate for targeted therapy via its natural ligand, hyaluronic acid (HA). We determined whether HA-paclitaxel conjugates were able to decrease tumor growth and improve survival in orthotopic nude mouse human SCCHN xenograft models. HA-paclitaxel concentration-dependent growth inhibition of human SCCHN cell lines OSC-19 and HN5 in vitro, very similarly to free paclitaxel treatment. Tumor cell uptake of FITC-labeled HA-paclitaxel was significantly blocked with free HA, indicating the dependence of uptake on CD44. HA-paclitaxel administered intravenously once per week for three weeks at 120 mg/kg paclitaxel equivalents, far above the paclitaxel maximum tolerated dose, exerted superior tumor growth control to that of paclitaxel in both orthotopic OSC-19-luciferase and HN5 xenograft models in vivo. Mouse survival following HA-paclitaxel administration was prolonged compared with that of controls in mice implanted with either of these xenografts. Mice treated with HA-paclitaxel displayed increased TUNEL(+) cells in tumor tissue, as well as markedly reduced microvessel density compared to those treated with free paclitaxel. No acute histopathological changes were observed in mice treated with HA-paclitaxel. Thus, we conclude that HA-paclitaxel effectively inhibits tumor growth in human SCCHN xenografts via an HA-mediated mechanism and this conjugate should be considered for further preclinical development for this disease.

Inhibition of 4-NQO-induced F433 rat tongue carcinogenesis by oleuropein-rich extract.

Olive leaf extract provides nutritional support for detoxification at the cellular level, when the body is under stress. The present study aimed to evaluate the chemopreventive effect of oleuropein-rich extract (ORE) on 4-NQO-induced rat tongue carcinogenesis. Eighty male F344 rats, 6 weeks age were divided into 5 groups (10 animals each for groups 1 and 2 and 20 each for groups 3, 4, and 5). Group 1 served as an untreated control. Group 2 was given ORE-containing diet alone. Rats of groups 3, 4, and 5 were given daily 20 ppm 4-NQO in drinking water for 8 weeks. Group 4 was fed diets containing ORE, concomitantly with the time of carcinogen exposure and continued 1 week after its stoppage. Group 5 was fed diets mixed with ORE starting 1 week after cessation of 4-NQO treatment. The experiment was terminated when the rats aged 37 weeks, and all animals were euthanized. The tongues were carefully inspected for pathological lesions, excised, and were processed for c-Met and Ki-67 immunohistochemical examination. The gross inspection, histopathological and immunohistochemical results of the present study showed a beneficial regression effect of ORE on tumor progression, especially when it was administered concomitantly with 4-NQO rather than when given after the stoppage of the carcinogenic material. In conclusion, ORE has a chemopreventive role in tongue squamous cell carcinoma, and further studies are needed to explore the molecular mechanisms of its tumor suppressive effect at this level.

Red mold dioscorea-induced G2/M arrest and apoptosis in human oral cancer cells.

BACKGROUND: Monascus-fermented products are among the most commonly used traditional food supplements. Dioscorea is known to exhibit anticancer properties. In this study the effects of the ethanol extract of red mold dioscorea (RMDE) on cell proliferation, cell cycle and apoptosis in human oral cancer cells were investigated. RESULTS: RMDE exercised growth inhibition on squamous cell carcinoma-25 (SCC-25) cells. RMDE-mediated G2/M phase arrest was associated with the down-regulation of NF-κB, resulting in the inhibition of cyclin B1 and CDK1 expression; this may be the mechanism by which RMDE inhibits cancer cells. Furthermore, the proapoptotic activity of RMDE was revealed by the Annexin V-FITC/PI double-staining assay. In addition, the proapoptotic effect of RMDE was evident by the inhibition of Bax expression in the mitochondria, resulting in the activation of caspase-9 and caspase-3 and subsequent triggering of the mitochondrial apoptotic pathway. RMDE also enhanced caspase-8 activity, indicating the involvement of the death receptor pathway in RMDE-mediated SCC-25 cell apoptosis. CONCLUSION: RMDE treatment inhibited the growth of SCC-25 cells by arresting cell cycle at the G2/M phase and induced apoptosis in a time- and dose-dependent manner. Therefore RMDE may be a good candidate for development as a dietary supplement against oral cancer.

Emodin, aloe-emodin and rhein inhibit migration and invasion in human tongue cancer SCC-4 cells through the inhibition of gene expression of matrix metalloproteinase-9.

Emodin, aloe-emodin and rhein are major compounds in rhubarb (Rheum palmatum L.), used in Chinese herbal medicine, and found to have antitumor properties including cell cycle arrest and apoptosis in many human cancer cells. Our previous studies also showed that emodin, aloe-emodin and rhein induced apoptosis in human tongue cancer SCC-4 cells. However, the detail regarding emodin, aloe-emodin and rhein affecting migration and invasion in SCC-4 cells are not clear. In the present study, we investigated whether or not emodin, aloe-emodin and rhein inhibited migration and invasion of SCC-4 cells. Herein, we demonstrate that emodin, aloe-emodin and rhein inhibit the protein levels and activities of matrix metalloproteinase-2 (MMP-2) but did not affect gene expression of MMP-2, however, they inhibited the gene expression of MMP-9 and all also inhibited the migration and invasion of human tongue cancer SCC-4 cells. MMP-9 (gelatinase-B) plays an important role and is the most associated with tumor migration, invasion and metastasis in various human cancers. Results from zymography and Western blotting showed that emodin, aloe-emodin and rhein treatment decrease the levels of MMP-2, urokinase plasminogen activator (u-PA) in a concentration-dependent manner. The order of inhibition of associated protein levels and gene expression of migration and invasion in SCC-4 cells are emodin >aloe-emodin >rhein. Our results provide new insight into the mechanisms by which emodin, aloe-emodin and rhein inhibit tongue cancers. In conclusion, these findings suggest that molecular targeting of MMP-9 mRNA expression by emodin, aloe-emodin and rhein might be a useful strategy for chemo-prevention and/or chemo-therapeutics of tongue cancers.