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1.
In light of the growing incidence of oral cancer in Taiwan, this study is aimed at investigating the antitumor activity of 3,3'-diindolylmethane (DIM), an active metabolite of the phytochemical indole-3-carbinol (I3C), in oral squamous cell carcinoma (OSCC). DIM exhibited substantially higher antiproliferative potency than I3C in three OSCC cell lines with IC(50) values in SCC2095, SCC9, and SCC15 cells, respectively, of 22 versus 168μM, 25 versus 176μM, and 29versus 300μM. Flow cytometric analysis and Comet assay indicated that DIM suppressed the viability of SCC2095 cells by inducing apoptosis and G2/M arrest. Western blot analysis of various signaling markers revealed the ability of DIM to target pathways mediated by Akt, mitogen-activated protein (MAP) kinases, nuclear factor (NF)-κB, and p53, of which the concerted action underlined its antitumor efficacy. The concomitant inactivation of Akt and MAP kinases in response to DIM facilitated the dephosphorylation of the proapoptotic protein Bad at Ser-136 and Ser-112, respectively. Through endoplasmic reticulum (ER) stress, DIM stimulated the activation of p53 via Ser-15 phosphorylation, leading to increased expression of the BH3-only proapoptotic Bcl-2 members Puma and Noxa. Together, these changes decreased the mitochondrial threshold for apoptosis. G2/M arrest might be attributable to the suppressive effect of DIM on the expression of cyclin B1 and cdc25c. As many downstream effectors of the Akt-NF-κB pathway, including glycogen synthase kinase 3β, IκB kinase α, and cyclooxygenase-2, have been shown to promote oral tumorigenesis, the ability of DIM to inhibit this signaling axis underscores its chemopreventive potential in oral cancer.  相似文献   

2.
Phenethyl isothiocyanate (PEITC) is a naturally occurring cruciferous vegetable-derived compound that inhibits cell growth and induces apoptosis in oral cancer cells. However, the exact mechanism of PEITC action has not been fully elucidated. This study investigated the molecular mechanism and anticancer potential of PEITC in oral squamous cell carcinoma (OSCC) cells with various p53 statuses. PEITC inhibited the growth of OC2, SCC4, and SCC25 cells (functional p53 mutants) in a dose-dependent manner with low toxicity to normal cells. Treatment with PEITC induced reactive oxygen species production, nitric oxide generation, and GSH depletion and triggered DNA damage response as evidenced by flow cytometry, 8-OHdG formation, and comet assay. Furthermore, the subsequent activation of ATM, Chk2, and p53 as well as the increased expression of downstream proteins p21 and Bax resulted in a G2/M phase arrest by inhibiting Cdc25C, Cdc2, and cyclin B1. The PEITC-induced apoptotic cell death, following a diminished mitochondrial transmembrane potential, reduced the expression of Bcl-2 and Mcl-1, released mitochondrial cytochrome c, and activated caspase 3 and PARP cleavage. The p53 inhibitor pifithrin-α and the antioxidants N-acetylcysteine and glutathione (GSH) protected the cells from PEITC-mediated apoptosis. However, mito-TEMPO, catalase, apocynin, and L-NAME did not prevent PEITC-induced cell death, suggesting that PEITC induced G2/M phase arrest and apoptosis in oral cancer cells via a GSH redox stress and oxidative DNA damage-induced ATM–Chk2–p53-related pathway. These results provide new insights into the critical roles of both GSH redox stress and p53 in the regulation of PEITC-induced G2/M cell cycle arrest and apoptosis in OSCCs.  相似文献   

3.
Oral cancer is one of the most common cancers worldwide, and squamous-cell carcinoma (OSCC) is the most common phenotype of oral cancer. Although patients with OSCC have poor survival rates and a high incidence of metastasis, the molecular mechanisms of OSCC development have not yet been elucidated. This study investigated whether N-myc downstream-regulated gene 2 (NDRG2) contributes to the carcinogenesis of OSCC, as NDRG2 is reported to be a candidate tumor-suppressor gene in a wide variety of cancers. The down-regulation of NDRG2 mRNA, which was dependent on promoter methylation, was seen in the majority of OSCC cases and in several cases of precancerous leukoplakia with dysplasia. Induction of NDRG2 expression in an HSC-3/OSCC cell line significantly inhibited cell proliferation and decreased colony formation ability on soft agar. The majority of OSCC cell lines showed an activation of PI3K/Akt signaling, and enforced expression of NDRG2 in HSC-3 cells decreased the level of phosphorylated Akt at Serine 473 (p-Akt). Immunohistochemical p-Akt staining was detected in 56.5% of the OSCC tumors, and 80.4% of the tumors were negative for NDRG2 staining. Moreover, positive p-Akt staining was inversely correlated with decreased NDRG2 expression in OSCC tumors with moderate to poor differentiation (< 0.005). Therefore, NDRG2 is a candidate tumor-suppressor gene for OSCC development and probably contributes to the tumorigenesis of OSCC partly via the modulation of Akt signaling.  相似文献   

4.
Methylxantine derivative, caffeine, is known to prevent the p53-dependent apoptosis pathway via inhibition of ATM (ataxia telangiectasia mutated) kinase, which activates p53 by phosphorylation of the Ser-15 residue. In contrast, it has been reported that caffeine induces p53-mediated apoptosis through Bax protein in non-small-cell lung cancer cells. Therefore, the effects of caffeine on cellular growth in malignant cells are controversial. We investigated the effects of caffeine on cell proliferation, cell cycle progression, and induction of apoptosis in NB4 promyelocytic leukemia cells containing wild-type p53. Caffeine suppressed the cellular growth of NB4 cells in a dose- and time-dependent manner. Caffeine induced G(2)/M phase cell cycle arrest in NB4 cells in association with the induction of phosphorylation at the Ser-15 residue of p53 and induction of tyrosine phosphorylation of cdc2. Expression of Bax protein was increased in NB4 cells after treatment with caffeine. Interestingly, the antisense oligonucleotides for p53 significantly reduced p53 expression and caffeine-induced G(2)/M phase cell cycle arrest in NB4 cells. These results suggest that caffeine induces cell cycle arrest and apoptosis in association with activation of p53 by a novel pathway to phosphorylate the Ser-15 residue and induction of phosphorylation of cdc 2 in leukemic cells with normal p53.  相似文献   

5.
6.
Oral cancer is the fourth most common cause of death from cancer in Taiwanese men. Indirubin-3′-monoxime (I3M), a potent cyclin-dependent kinase inhibitor, has therapeutic effects in other cancer cells. In this study, we carried out in vitro assays to test cell viability, cell cycle progression, apoptosis, cell migration and invasion in this cancer type. In addition, using an oral tumorigenic animal model, we examined target gene and protein expression using real time qPCR, immunoblotting and immunohistochemical staining. Our results demonstrate that I3M has an anti-proliferative effect in both Cal-27 and HSC-3 oral cancer cell lines and that treatment of Cal-27 and HSC-3 cells with I3M results in apoptosis through the activation of cytochrome c. In addition, I3M interrupts the cell cycle in Cal-27 cells in a dose-dependent manner by arresting cells in the G2/M phase. We also found that I3M suppresses migration and invasion in Cal-27 cells by inhibiting the expression of focal adhesion kinase, urokinase-type plasminogen inhibitor, and matrix metalloproteinase 9. Moreover, we identified survivin as a target protein in I3M-treated oral cancer cells. Using an oral cancer mouse model, we demonstrate that topical application of an adhesive gel composed of I3M and poly(vinyl alcohol) (I3M/PVA) has dose-dependent anti-tumorigenic effects. Following treatment, the expression of survivin protein and mRNA was downregulated in cancerous tissues. Furthermore, plasma survivin levels were also reduced in the I3M-treated mice. These results suggest that topical application of I3M, a drug synthesized from indirubin, which is found in Qing-Dai – has therapeutic potential for treating oral cancer.  相似文献   

7.
8.
G protein-coupled receptor (GPR) 119 is highly expressed in pancreatic β-cells and enhances the effect of glucose-stimulated insulin secretion (GSIS) on activation. The development of an oral GPR119 agonist that specifically targets the first phase of GSIS represents a promising strategy for the treatment of type 2 diabetes. In the present study, we evaluated the therapeutic potential of a novel small molecule GPR119 agonist, AS1535907, which was modified from the previously identified 2,4,6-tri-substituted pyrimidine core agonist AS1269574. AS1535907 displayed an EC50 value of 4.8 μM in HEK293 cells stably expressing human GPR119 and stimulated insulin secretion in rat islets only under high-glucose (16.8 mM) conditions. In isolated perfused pancreata from normal rats, AS1535907 enhanced the first phase of insulin secretion at 16.8 mM glucose, but had no effect at 2.8 mM glucose. In contrast, the sulfonylurea glibenclamide predominantly induced insulin release in the second phase at 16.8 mM glucose and also markedly stimulated insulin secretion at 2.8 mM glucose. In in vivo studies, a single 10 μM administration of AS1535907 to diabetic db/db mice reduced blood glucose levels due to the rapid secretion of insulin secretion following oral glucose loading. These results demonstrate that GPR119 agonist AS1535907 has the ability to stimulate the first phase of GSIS, which is important for preventing the development of postprandial hypoglycemia. In conclusion, the GPR119 agonist AS1535907 induces a more rapid and physiological pattern of insulin release than glibenclamide, and represents a novel strategy for the treatment of type 2 diabetes.  相似文献   

9.
One of the most important factors determining the success of the development of cloned embryos is the cell cycle stage of the donor cells. We investigated the effects of serum starvation, culturing to confluence and roscovitine treatment on the cell cycle synchronization of goldfish caudal fin-derived fibroblasts by flow cytometric analysis. The results show that culturing the cells to confluence (85.5%) and roscovitine treatment (82.71%) yield a significantly higher percentage of cells arrested in the G0/G1 (P < 0.05) phase than serum starvation (62.85%). Different concentrations of roscovitine (5, 10, or 15 μM) induce cell cycle arrest at the G0/G1 phase.  相似文献   

10.
Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence.  相似文献   

11.
Betel quid (BQ) is a widely accepted etiological factor for oral squamous cell carcinoma (OSCC) in Southeast Asia, but how BQ chewing leads to oral carcinogenesis remains to be elucidated. We have previously demonstrated that the activation of Src family kinases (SFKs) is critical for BQ-induced oral cancer cell motility. Here we investigate whether this biological effect is mediated by specific membrane receptors in oral cancer cells. We found that BQ-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and cell migration could be inhibited by atropine, suggesting the involvement of the muscarinic receptor family. The enhanced activities of ERK1/2 and cell migration were significantly counteracted by PD102807, the selective antagonist of muscarinic M4 receptor. Moreover, cold BQ extract effectively competed with a known ligand, [3H]-N-methyl scopolamine, for binding to muscarinic M4 receptor in vitro, thereby implying that BQ could activate motility-promoting signaling pathways through direct interaction with the receptor. The requirement of muscarinic M4 receptor for BQ-induced oral cancer cell migration was demonstrated by knockdown of the receptor using RNA interference (RNAi). Remarkably, ectopic expression of muscarinic M4 receptor in two oral cancer cell lines, Ca9-22 and SCC-9, further augmented BQ-induced cell migration by 83% and 99%, respectively. Finally, we verified that BQ-induced oral cancer cell migration was mediated through a muscarinic M4 receptor → SFKs → ERK1/2 signaling pathway. Thus, our findings have identified a novel signaling cascade mediating BQ-induced oral cancer cell motility, which could be a therapeutic target for BQ-related oral malignancies.  相似文献   

12.
Wang Y  Liu Q  Liu Z  Li B  Sun Z  Zhou H  Zhang X  Gong Y  Shao C 《Mutation research》2012,734(1-2):20-29
Berberine has been shown to possess anti-tumor activity against a wide spectrum of cancer cells. It inhibits cancer cell proliferation by inducing cell cycle arrest, at G1 and/or G2/M, and apoptosis. While it has been documented that berberine induces G1 arrest by activating the p53-p21 cascade, it remains unclear what mechanism underlies the berberine-induced G2/M arrest, which is p53-independent. In this study, we tested the anti-proliferative effect of berberine on murine prostate cancer cell line RM-1 and characterized the underlying mechanisms. Berberine dose-dependently induced DNA double-strand breaks and apoptosis. At low concentrations, berberine was observed to induce G1 arrest, concomitant with the activation of p53-p21 cascade. Upon exposure to berberine at a higher concentration (50μM) for 24h, cells exhibited G2/M arrest. Pharmacological inhibition of ATM by KU55933, or Chk1 by UCN-01, could efficiently abrogate the G2/M arrest in berberine-treated cells. Downregulation of Chk1 by RNA interference also abolished the G2/M arrest caused by berberine, confirming the role of Chk1 in the pathway leading to G2/M arrest. Abrogation of G2/M arrest by ATM inhibition forced more cells to undergo apoptosis in response to berberine treatment. Chk1 inhibition by UCN-01, on the other hand, rendered cells more sensitive to berberine only when p53 was inhibited. Our results suggest that combined administration of berberine and caffeine, or other ATM inhibitor, may accelerate the killing of cancer cells.  相似文献   

13.
14.
Cell division cycle associated 2 (CDCA2) recruits protein phosphatase 1 to chromatin to antagonize activation of ataxia telangiectasia mutated (ATM)-dependent signal transduction. ATM kinase plays a critical role in the DNA damage response and its phosphorylation cascade to inhibit the p53-MDM2 interaction, which releases p53 to induce p21 and G1 cell-cycle arrest. However, the relevance of CDCA2 to human malignancy including oral squamous cell carcinoma (OSCC) is unknown. In the current study, we found that CDCA2 expression was up-regulated in OSCC cell lines. Functional studies with shRNA system showed that knockdown of CDCA2 significantly (P<0.05) inhibited cellular proliferation compared with the control cells by arresting cell-cycle progression at the G1 phase and up-regulating the cyclin-dependent kinase inhibitors (p21Cip1, p27Kip1, p15INK4B, and p16INK4A). CDCA2 knockdown also promoted apoptosis after treatment with the DNA damage reagent, cisplatin. In clinical samples, the CDCA2 protein expression level in primary OSCCs was significantly (P<0.05) greater than in matched normal oral tissues (67/85, 79%). Furthermore, CDCA2-positive cases were correlated significantly (P<0.05) with high cancer progression. Our results showed for the first time that CDCA2 frequently is overexpressed in OSCCs and might be associated closely with OSCC progression by preventing cell-cycle arrest and apoptosis.  相似文献   

15.
The aim of this study was to explore the anti-tumor potential of a polysaccharide isolated from Boschniakia rossica (BRP) in Hep2 human larynx squamous carcinoma cells. High performance size-exclusion chromatography analysis showed that BRP was a homogeneous polysaccharide and had a molecular weight of 22 kDa. Total carbohydrate content in BRP was determined to be 96.9%, without the presence of protein and nucleic acid. BRP suppressed the proliferation of Hep2 cells in a time- and dose-dependent manner. Cell cycle analysis revealed that exposure to BRP (200 μg/ml) caused a G0/G1 cell cycle arrest in Hep2 cells. Moreover, treatment with BRP at 100–400 μg/ml for 24 h induced a significant apoptosis Hep2 cells compared to untreated control cells, as determined by flow cytometry with annexin-V/propidium iodide double staining. Additionally, BRP treatment promoted the cleavage of pro-caspase-3, pro-caspase-8, and pro-caspase-9, coupled with increased expression of death receptor DR5 and Bax and reduced expression of Bcl-2. Taken together, our data demonstrate that BRP shows potent anti-tumor activity in human larynx squamous carcinoma, largely through induction of G0/G1 cell cycle arrest and apoptosis. Activation of both mitochondria-mediated and death receptor-mediated apoptosis pathways is involved in the cytotoxicity of BRP.  相似文献   

16.

Background

Oral squamous cell carcinoma (OSCC) is one of the most common malignant neoplasms in Taiwan. Activation of the mTOR signaling pathway has been linked to decreased radiation responsiveness in human oral cancer, thus it limits efficacy of radiotherapy. To address this question, we investigated the effect of AZD2014, a novel small molecular ATP-competitive inhibitor of mTORC1 and mTORC2 kinase, as a radiosensitizer in primary OSCC and OSCC-derived cell line models.

Methods

We isolated primary tumor cells from OSCC tissues and cell lines. AZD2014 was administered with and without ionizing radiation. The radiosensitizing effect of AZD2014 were then assessed using cell viability assays, clonogenic survival assays, and cell cycle analyses. Western blotting was used to detect protein expression.

Results

Combination treatment with AZD2014 and irradiation resulted in significant reduction in OSCC cell line and primary OSCC cell colony formation due to the enhanced inhibition of AKT and both mTORC1 and mTORC2 activity. Pre-treatment with AZD2014 in irradiated oral cancer cells induced tumor cell cycle arrest at the G1 and G2/M phases, which led to disruption of cyclin D1-CDK4 and cyclin B1-CDC2 complexes. Moreover, AZD2014 synergized with radiation to promote both apoptosis and autophagy by increasing caspase-3 and LC3 in primary OSCC cells.

Conclusions

These findings suggest that in irradiated OSCC cells, co-treatment with AZD2014, which targets mTORC1 and mTORC2 blockade, is an effective radiosensitizing strategy for oral squamous cell carcinoma.  相似文献   

17.
2-Hydroxycinnamaldehyde (HCA) and curcumin have been reported to have antitumor effects against various human tumor cells in vitro and in vivo by generation of ROS. Aldehyde-free HCA analogs were synthesized based on the structure of curcumin, which we have called 2-hydroxycurcuminoids. The hydroxyl group of curcuminoids enhances the ability to generate ROS. 2-Hydroxycurcuminoid (HCC-7) strongly inhibited the growth of SW620 colon tumor cells with a GI50 value of 7 μM, while the parent compounds, HCA and curcumin, displayed GI50 values of 12 and 30 μM, respectively. HCC-7 was found to induce apoptosis through the reactive oxygen species-mitochondria pathway and cell cycle arrest at G2/M phase.  相似文献   

18.
Oral cancers constitute approximately 2% of all cancers, with the most common histological type being oral squamous cell carcinoma (OSCC), representing 90% of oral cancers. Although diagnostic technologies and therapeutic techniques have progressed, the survival rate of patients with OSCC is still 60%, whereas the incidence rate has increased. Podocalyxin (PODXL) is a highly glycosylated type I transmembrane protein that is detected in normal tissues such as heart, breast, and pancreas as well as in many cancers, including lung, renal, breast, colorectal, and oral cancers. This glycoprotein is associated with the progression, metastasis, and poor outcomes of oral cancers. PODXL overexpression was strongly detected using our previously established anti-PODXL monoclonal antibody (mAb), PcMab-47, and its mouse IgG2a-type, 47-mG2a. In previous studies, we also generated PODXL-knock out (PODXL-KO) cell lines using SAS OSCC cell lines, in order to investigate the function of PODXL in the proliferation of oral cancer cells. The growth of SAS/PODXL-KO cell lines was observed to be lower than that of parental SAS cells. For this study, PODXL-KO OSCC cell lines were generated using HSC-2 cells, and the role of PODXL in the growth of OSCC cell lines in vitro was assessed. Decreased growth was observed for HSC-2/PODXL-KO cells compared with HSC-2 parental cells. The influence of PODXL on tumor growth of OSCC was also investigated in vivo, and both the tumor volume and the tumor weight were observed to be significantly lower for HSC-2/PODXL-KO than that for HSC-2 parental cells. These results, taken together, indicate that PODXL plays an important role in tumor growth, both in vitro and in vivo.  相似文献   

19.
Celecoxib, a clinical non-steroidal anti-inflammatory drug, displays anticarcinogenic and chemopreventive activities in human colorectal cancers, although the mechanisms of apoptosis by celecoxib are poorly understood. The existence of functional p53 but not securin in colorectal cancer cells was higher on the induction of cytotoxicity than the p53-mutational colorectal cancer cells following celecoxib treatment. The p53-wild type HCT116 cells were more susceptible to increase ∼25% cell death than the p53-null HCT116 cells after treatment with 100 μM celecoxib for 24 h. Transfection with a small interfering RNA of p53 reduced the celecoxib-induced cytotoxicity in the RKO (p53-wild type) colorectal cancer cells. Celecoxib (80-100 μM for 24 h) significantly increased total p53 proteins and the phosphorylated p53 proteins at serine-15, -20, -46, and -392 in RKO cells. However, the phospho-p53 (serine-15, -20, and -392) proteins were presented on the nuclei of cells but the phospho-p53 (serine-46) protein was located on the cytoplasma of apoptotic cells following treatment with celecoxib. Interestingly, the p53 up-regulated modulator of apoptosis (PUMA) protein, which located on the mitochondria, was induced by celecoxib in the p53-functional colorectal cancer cells but not in the p53-mutational cells. Together, this study provides the first time that celecoxib induces the various phosphorylated sites of p53 and activates p53-PUMA pathway, which potentiates the apoptosis induction in human colorectal cancer cells.  相似文献   

20.
Loss of cardiomyocytes through apoptosis has been proposed as a cause of ventricular remodeling and heart failure. Ischemia- and hypoxia-induced apoptosis of cardiomyocytes reportedly plays an important role in many cardiac pathologies. We investigated whether resveratrol (Res) has direct cytoprotective effects against ischemia/hypoxia for cardiomyocytes. Exposure of H9c2 embryonic rat heart-derived cells to hypoxia for 24 h caused a significant increase in apoptosis, as evaluated by TUNEL and flow cytometry, while treatment with 20 μM Res greatly decreased hypoxia-induced apoptosis in these cells. Exposure of the cells to Res (20 μM) caused rapid activation of SIRT1, which had a dual effect on FoxO1 function: SIRT1 increased FoxO1’s ability to induce cell cycle arrest, but inhibited FoxO1’s ability to induce cell death. This effect could be reversed by SIRT1 inhibition. Results of our study indicate that Res inhibits hypoxia-induced apoptosis via the SIRT1-FoxO1 pathway in H9c2 cells. This polyphenol may have potential in preventing cardiovascular disease, especially in coronary artery disease (CAD) patients.  相似文献   

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