Laryngeal Carcinoma Cell Line Research Articles

Consumer acceptability of liquorice root (Glycyrrhiza glabra L.) as an alternative sweetener and correlation with its bioactive content and biological activity

Consumer acceptability and sensory properties of liquorice root (Glycyrrhiza glabra L.) were evaluated. Quantitation of total polyphenolics and glycyrrhizic acid (GA), as well as the antioxidant capacity of liquorice extracts, was conducted and their biological effects (cytotoxic, antioxidative/pro-oxidative activity, lipid peroxidation on human laryngeal carcinoma cell line) compared to the ones of their predominant bioactive compound – GA. Conducted consumer survey revealed poor familiarity with liquorice (12.37% of correspondents), but willingness towards its use as an alternative sweetener (77.32% of consumers). Polyphenolic content of evaluated extracts ranged from 1018.18 to 1277.27 mg gallic acid equivalents (GAE)/l while GA content varied between 2179.53 and 2944.13 mg/l. The most pronounced cytotoxic effect (60%) and lipid peroxidation were exerted by treatment with the highest applied extract concentrations (10 mg/ml). Pure GA exhibited cytotoxic and pro-oxidative effects at concentrations of 0.12–0.6 mg/ml. Due to high GA content, coupled with its pronounced cytotoxic activity, the intake of liquorice root should be limited.

Comparative evaluation of PLGA nanoparticle delivery system for 5-fluorouracil and curcumin on squamous cell carcinoma

PurposeThe purpose of this study is to assess the effect of 5-fluorouracil nanoparticles and curcumin naoparticles on cell proliferation and the expression of the apoptotic marker (caspase 3) in squamous cell carcinoma cell line. Material and methodsPLGA 5-fluorouracil nanopartciles and PLGA curcumin nanoparticles were prepared and applied for 24 and 48h on human laryngeal squamous carcinoma cell line (Hep-2) as regard IC 50 concentration. MTT assay was used for evaluation of cytotoxicity of prepared nanoparticles. Quantitaive reverse transcriptase polymerase chain reaction (QRT-PCR) was used for the assessment of caspase-3 expression in the treated cell line. ResultsThe drug release rate profiles was dependent upon polymer to drug ratio, noting that the higher PLGA polymer ratio to 5-fluprouracil or curcumin drug showed faster release rates. On the other hand, the least PLGA polymer ratio to 5-fluprouracil or curcumin drug showed the slowest release rates. MTT assay revelaed that 5-fluorouracil nanoparticels or curcumin nanoparticels showed a clear cytotoxic effect on Hep-2 cell line compared to non treated cancer cells. The RT-PCR assessment of caspase-3 expression revealed that there was a significant increase in caspase-3 expression in Hep-2 cell line treated with 5-fluorouracil nanoparticles or curcumin compared to non treated cancer cells. ConclusionCurcumin nanoparticles could be more active in inducing apoptosis in short term assays (24h) than long term assays (48h) due to differential cellular uptake. While 5-fluorouracil nanoparticles induced higher significant apoptosis in long term (48h) compared to curcumin group.

Haemophilus influenzae triggers autophagy in HEp-2 cells.

The MAP-LC3 system regulates the intracellular formation of autophagy-associated vacuoles. These vacuoles contain the LC3 protein; thus it has been utilized as a marker to identify autophagosomes. The aim of our study was to investigate whether Haemophilus influenzae strains and their supernatants could activate autophagy in human larynx carcinoma cell line (HEp-2). We demonstrate that higher expression of the LC3B-II protein was induced, particularly by nontypeable Haemophilus influenzae (NTHi) 49766 and by supernatants, containing <50 kDa proteins, of both strains. Ultrastructural studies demonstrate vacuoles with a double membrane and/or membrane material inside, showing similar features to those of autophagic vacuoles. Together, our findings demonstrate that H. influenzae strains and their supernatants trigger an autophagic process.

A preliminary study of the effect of ECRG4 overexpression on the proliferation and apoptosis of human laryngeal cancer cells and the underlying mechanisms.

Human esophageal cancer-related gene 4 (ECRG4) is a potential tumor suppressor gene isolated from human esophageal epithelial cells. Studies have shown that ECRG4 effectively inhibits the proliferation of tumor cells and induces apoptosis. However, the role of ECRG4 in laryngeal cancer has not yet been clearly defined. In this study, a human laryngeal cancer cell line stably overexpressing ECRG4 was established. The effect of ECRG4 on the proliferation and apoptosis of laryngeal cancer cells and the associated mechanisms were investigated. The Hep-2 human laryngeal carcinoma cell line exhibited a low basal level of ECRG4 expression and was selected for the present study. The eukaryotic expression plasmid pcDNA3.1-ECRG4 was constructed and introduced into Hep-2 cells by transfection reagents. Western blot analysis, reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining confirmed high-level expression of ECRG4. The 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and colony formation assay showed that ECRG4 over-expression suppressed the proliferative capacity of laryngeal cancer cells in vitro. Cell cycle analysis showed that ECRG4 induced cell cycle arrest at the G0/G1 phase. Flow cytometric analysis and Hoechst staining demonstrated that overexpres-sion of ECRG4 significantly induced apoptosis. Western blot analysis confirmed that Bcl-2-associated X protein, cleaved-caspase-3 and cleaved-poly (ADP-ribose) polymerase were upregulated in the apoptotic process, whereas B-cell lymphoma 2 was downregulated. In conclusion, overexpression of ECRG4 inhibited laryngeal cancer cell proliferation and induced cancer cell apoptosis. Therefore, ECRG4 exhibits potential as an effective target in gene therapy for laryngeal cancer.

Cytotoxic activity of Phyllanthus emblica Linn. cultivated in Egypt against colon and larynx carcinoma cell lines

Phyllanthus emblica (Euphorbiaceae) is one of the most extensively used plants in the traditional Indian system of medicine (Ayurveda). This in vitro study aims to evaluate the cytotoxic activity of P. emblica extracts (leaves, fruits and stem branches) as well as some isolated compounds against HCT-116 (colon carcinoma) and HEP-2 (larynx carcinoma) cell lines. The results showed that dichloromethane (DCM) extract of the fruits, gallic acid, hexane extract of the stem branches and pet. Ether extract of the fruits had a significant cytotoxic activity (IC50= 4.8 µg/ml, 6.17 µg/ml, 9.92 µg/ml, 9.98 µg/ml, respectively) against HCT-116 cell line. Concerning HEP-2 cell line highest activity exhibited by the DCM extract of the fruits (IC50= 8.1 µg/ml), gallic acid (IC50= 10.3 µg/ml), hexane extract of the stem branches (IC50= 11.3 µg/ml). Other tested compounds were 1,2,4,6-tetra galloyl β-D- glucose, 1-O-galloyl glycerol, mucic acid, Naringenin 7-O-(6″-O-galloyl)-β-D-glucoside and lupeol.

English

The aim of this study was to analyze the antitumor activity of Anacardium humile A. St.-Hil., Brosimum gaudichaudii Tr&eacute;cul and Tabebuia avellanedae Lorentz ex Griseb species, which are distributed in the Cerrado region of Brazil. Qualitative and quantitative analyses were also conducted on the bark and leaf extracts and antioxidant and cytotoxic activities were studied. The results showed that the bark and leaf extracts of A. humile exhibited the highest contents of phenolic compounds and optimal antioxidant activity. The leaf extract of T. avellanedae had the highest content of flavonoids, displayed high efficiency as a ferrous ion chelating agent and inhibited the growth of the human laryngeal carcinoma (HEp-2) cell line by 88.0% at the concentration of 50 &micro;g/ml. The leaves of B. gaudichaudii had higher levels of condensed tannins, flavonoids and coumarins compared with that of the bark. There was a correlation between inhibition of the NCI- human lung cancer (H292) cell line and the content of condensed tannins and antiradical activity and also between the inhibition of human colon carcinoma (HT-29) cell growth and the antioxidant and chelating activity of ferrous ion. Our data provide evidence that bark and leaf extracts of A. humile and leaves of T. avellanedae possess anticancer activity; therefore, the isolation and identification of the active ingredients of these plant tissues should be conducted to explore their therapeutic potential. &nbsp; Key words: Antiproliferative, Hep-2 cells, HT-29 cells, medicinal plants, NCI-H292 cells, phenolic compounds.

Radioresistance in a human laryngeal squamous cell carcinoma cell line is associated with DNA methylation changes and topoisomerase II α

Accumulating evidence suggests that changes in methylation patterns may help mediate the sensitivity or resistance of cancer cells to ionizing radiation. The present study provides evidence for the involvement of radioresistance-induced DNA methylation changes in tumor radioresistance. We established radioresistant laryngeal cancer cells via long-term fractionated irradiation, and examined differences in DNA methylation between control and radioresistant laryngeal cancer cells. Interestingly, we found that the promoter-CpG islands of 5 previously identified radioresistance-related genes (TOPO2A, PLXDC2, ETNK2, GFI1, and IL12B) were significantly altered in the radioresistant laryngeal cancer cells. Furthermore, the demethylation of these gene promoters with a DNA methyltransferase inhibitor (5-aza-2'-deoxycytidine) increased their transcription levels. Treatment with 5-aza-2'-deoxycytidine also sensitized the radioresistant laryngeal cancer cells to irradiation, indicating that changes in DNA methylation contributed to their radioresistance. Of the tested genes, the expression and activity levels of TOPO2A were tightly associated with the radioresistant phenotype in our system, suggesting that the hypermethylation of TOPO2A might be involved in this radioresistance. Collectively, our data suggest that radiation-induced epigenetic changes can modulate the radioresistance of laryngeal cancer cells, and thus may prove useful as prognostic indicators for radiotherapy.

MicroRNA-221 accelerates the proliferation of laryngeal cancer cell line Hep-2 by suppressing Apaf-1.

Laryngeal cancer is one of the most commonly occurring malignant cancers of the head and neck region. In the present study, we investigated the roles of miR-221 in laryngeal squamous cell carcinoma cell line, Hep-2. We examined the function and mechanism of miR-221 in Hep-2 cells using techniques of cell biology and molecular pathology, such as western blotting, quantitative PCR, immunohistochemical staining and flow cytometry. Using a luciferase assay, the apoptotic protease activating factor-1 (Apaf-1) mRNA 3'-UTR was shown to have complementary binding sites using bioinformatics prediction software including TargetScan, PicTar and miRanda. In conclusion, our results showed that miR-221 inhibition caused elevated expression levels of the Apaf-1 apoptotic pathway proteins caspase-3, -8 and -9. miR-221 may therefore be used as a novel therapeutic target for laryngeal cancer.

Antiproliferative efficacy of Tabernaemontana divaricata against HEP2 cell line and Vero cell line.

Background:Laryngeal cancer may also be called cancer of the larynx or laryngeal carcinoma. Conventional plants are a precious source of novel anticancer agents and are still in performance better role in health concern. The study was intended to estimation of the anticancer activity of the chloroformic extract of Tabernaemontana divaricata on the human epidermoid larynx carcinoma cell line (Hep 2).Materials and Method:The aerial parts (leaves, stem, and flowers) of T. divaricata were tested for its inhibitory effect in 96 microplate formats against Hep 2 cell line. The anticancer activity of samples on Hep 2 and Vero was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and various enzymatic parameters like catalase, reduced glutathione (GSH), GSH peroxidase, and superoxide anion scavenging activity. Viable cells were determined by the absorbance at 540 nm. Measurements were performed, and the concentration required for a 50% inhibition of viability (IC50) was determined graphically. The effect of the samples on the proliferation of Hep 2 and Vero cells was expressed as the % cell viability.Results:The extract on Hep 2 cell line up to 7.8 μg/ml and that IC50 value on Hep 2 cell line was 112 μg whereas 94 μg for Vero cell line. Hence, T. divaricata has lesser significant action on Vero cell line.Conclusion:Medicinal plant drug discovery continues to provide new and important leads against various pharmacological targets including cancer. Our results clearly indicate the anticancer property of the medicinal plant T. divaricata against the human laryngeal carcinoma cell lines (Hep 2 cell line).

Green synthesis of silver nanoparticles using the mushroom fungus Schizophyllum commune and its biomedical applications

Silver nanoparticles, which are small metallic colloidal particles, ranging 1 ∼ 100 nm in size, have several nano biotechnological applications in medicine, manufacturing and engineering industries. Fungus-mediated synthesis of silver nanoparticles is an ecofriendly, green process. Further, extracellular enzymes and proteins elaborated by fungi are involved in the synthesis of the silver nanoparticle, which makes the downstream processing relatively simpler. In the present investigation, Schizophyllum commune, a mushroom fungus, was tested for its ability to synthesize extracellular as well as intracellular silver nanoparticles. When the fungus was challenged with 1 mM silver nitrate, a change in colour of the broth and the mycelium was observed, indicative of extracellular and intracellular synthesis of silver nanoparticles. The presence of silver nanoparticles was confirmed by studying its Surface Plasmon Resonance absorption band in the visible wavelength. FTIR spectrum analysis of the silver nanoparticles indicated the presence of biomolecules in association with the reduction of silver ions. Scanning Electron Microscopic analysis of the silver nanoparticles revealed the nanorange dimensions of both the extracellular and the intracellular silver nanoparticles. Analysis of biological activities of the silver nanoparticles disclosed their significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens. Additionally, the silver nanoparticles inhibited the growth of the dermatophytic fungal pathogens viz. Trichophyton simii, Trichophyton mentagrophytes and Trichophyton rubrum significantly. Anticancer activity of silver nanoparticles, assayed through MTT cytotoxicity assay, uncovered that 27.2 and 64% mortality could be obtained in Human Epidermoid Larynx Carcinoma (HEP -2) cell lines at concentrations between 10 and 100 µg/mL, respectively. The results obtained indicate that Schizophyllum commune is capable of synthesizing silver nanoparticles in shaken broth cultures (120 rpm) at 25 ± 2℃ and pH 7.

Inhibitory effect of full-length spleen tyrosine kinase on invasion and metastasis of human laryngeal squamous cells

To study the effect of gene transfection of full length spleen tyrosine kinase (Syk (L)) on the biological behavior of malignant cancer cells. Eukaryotic expression vector pIRES2-EGFP-Syk (L) was constrauted and sequenc. Laryngeal carcinoma cell line Hep-2 were transfected with pIRES2-EGFP-Syk (L) vectors or blank vectors. The expressions of mRNA and protein were examined by real time fluorescence quantitative polymerase chain reaction (Q-RT-PCR) and Western blot analysis. CCK-8 method was used for evaluating cell proliferation, Transwell for cell invasion capacity in vitro, and tumor formation in nude mice for in vivo tumorigenicity. pIRES2-EGFP-Syk (L) vectors were successfully construct and transfected to Hep-2 cells. Q-PCR showed that mRNA expression level in Hep-2 cells transfected with Sky (L) (28.395 ± 0.067) was higher than those in Hep-2-neo cells transfected with blank vectors (3.891 ± 0.021) and Hep-2 cells with no transfection (1.005 ± 0.012), with statistically significant difference (F = 104.02, P < 0.01). Western blot showed that protein expression level of transfected-Sky (L) cells (0.821 ± 0.047) was significantly higher than those of Hep-2-neo cells (0.558 ± 0.031) and Hep-2 cells (0.468 ± 0.031), and the difference was statistically significant (F = 112.32, P < 0.01) ; CCK-8 assay showed OD value (1.390 ± 0.067) of transfected-Sky (L) cells was lower than those of Hep-2-neo cells (1.830 ± 0.067) and Hep-2 cells (1.920 ± 0.040), and the difference was statistically significant (F = 107.64, P < 0.01). Transwell assay showed average cell number per field of transfected-Sky (L) cells (176.04 ± 22.32) was higher than those of Hep-2-neo cells (301.02 ± 21.45) and Hep-2 cells (336.04 ± 26.01) with statistically significant difference (F = 123.46, P < 0.01). The volume (250.77 ± 34.83) mm(3) tumor formed from transfected-Sky (L) cells in nude mice, was less than those from Hep-2-neo cells (750.77 ± 40.83) mm(3) and Hep-2 cells (770.77 ± 30.83) mm(3), with statistically significant difference (F = 165.78, P < 0.01). Down-regulation of Syk in Hep-2 cells is associated with the malignant biological behaviors of the cells. Syk (L) may be a potential target in gene therapy for laryngeal squamous cell carcinoma.

Overexpression of microRNA-30b improves adenovirus-mediated p53 cancer gene therapy for laryngeal carcinoma.

MicroRNAs play important roles in laryngeal carcinoma and other cancers. However, the expression of microRNAs in paracancerous tissue has been studied less. Here, using laser capture microdissection (LCM), we detected the expression of microRNAs in paracancerous tissues. Among all down-regulated microRNAs in the center area of tumor tissues, only miR-30b expression was significantly reduced in paracancerous tissues compared to surgical margins. Therefore, to further investigate the effect of miR-30b on laryngeal carcinoma, we stably overexpressed miR-30b in laryngeal carcinoma cell line HEp-2 cells. It was found that although there was no significant difference in cell viability between miR-30b overexpressed cells and control HEp-2 cells, p53 expression was obviously enhanced in miR-30b overexpressed cells. Whether miR-30b could improve the anti-tumor effect of adenovirus-p53 (Ad-p53) in laryngeal carcinoma and other cancer cell lines was also evaluated. It was found that in miR-30b overexpressed HEp-2 cells, p53-mediated tumor cell apoptosis was obviously increased both in vitro and in vivo. MDM2-p53 interaction might be involved in miR-30b-mediated anti-tumor effect. Together, results suggested that miR-30b could modulate p53 pathway and enhance p53 gene therapy-induced apoptosis in laryngeal carcinoma, which could provide a novel microRNA target in tumor therapy.

6α-Hydroxy-α-toxicarol and (+)-tephrodin with antiplasmodial activities from Tephrosia species

The CH2Cl2/MeOH (1:1) extract of the roots of Tephrosia villosa showed good antiplasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 3.1±0.4 and 1.3±0.3μg/mL, respectively. Chromatographic separation of the extract yielded a new rotenoid, 6α-hydroxy-α-toxicarol, along with five known rotenoids, (rotenone, deguelin, sumatrol, 12a-hydroxy-α-toxicarol and villosinol). Similar treatment of the extract of the stem of Tephrosia purpurea (IC50=4.1±0.4 and 1.9±0.2μg/mL against D6 and W2 strains of P. falciparum, respectively) yielded a new flavone having a unique substituent at C-7/C-8 [trivial name (+)-tephrodin], along with the known flavonoids tachrosin, obovatin methyl ether and derrone. The relative configuration and the most stable conformation in (+)-tephrodin was determined by NMR and theoretical energy calculations. The rotenoids and flavones tested showed good to moderate antiplasmodial activities (IC50=9−23μМ). Whereas the cytotoxicity of rotenoids is known, the flavones (+)-tephrodin and tachrosin did not show significant cytotoxicity (IC50>100μМ) against mammalian African monkey kidney (vero) and human larynx carcinoma (HEp2) cell lines.

Constituents of the roots and leaves of Ekebergia capensis and their potential antiplasmodial and cytotoxic activities.

A new triterpenoid, 3-oxo-12β-hydroxy-oleanan-28,13β-olide (1), and six known triterpenoids 2–7 were isolated from the root bark of Ekebergia capensis, an African medicinal plant. A limonoid 8 and two glycoflavonoids 9–10 were found in its leaves. The metabolites were identified by NMR and MS analyses, and their cytotoxicity was evaluated against the mammalian African monkey kidney (vero), mouse breast cancer (4T1), human larynx carcinoma (HEp2) and human breast cancer (MDA-MB-231) cell lines. Out of the isolates, oleanonic acid (2) showed the highest cytotoxicity, i.e., IC50’s of 1.4 and 13.3 µM against the HEp2 and 4T1 cells, respectively. Motivated by the higher cytotoxicity of the crude bark extract as compared to the isolates, the interactions of oleanonic acid (2) with five triterpenoids 3–7 were evaluated on vero cells. In an antiplasmodial assay, seven of the metabolites were observed to possess moderate activity against the D6 and W2 strains of P. falciparum (IC50 27.1–97.1 µM), however with a low selectivity index (IC50(vero)/IC50(P. falciparum-D6) < 10). The observed moderate antiplasmodial activity may be due to general cytotoxicity of the isolated triterpenoids.

Diversified expression of aryl hydrocarbon receptor dependent genes in human laryngeal squamous cell carcinoma cell lines treated with β-naphthoflavone

The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. In this study the effect of administration of β-naphthoflavone (BNF), potent AhR ligand, on the expression of AhR, AhRR, CYP1A1, CYP1A2, CYP1B1, NQO1, GSTA1, ALDH3A1 and UGT1A genes encoding the enzymes controlled by AhR were examined in thirteen laryngeal tumor cell lines and in HepaRG cell line. The analyzed cell lines were derived from patients with squamous laryngeal cancer, with history of cigarette smoking and without signs of human papillomavirus types 16 and 18 infection in investigated cells. Quantitative real-time RT-PCR analysis revealed huge interindividual differences in expression of genes from AhR regulatory network. Our results strongly suggest predominant effect of DNA methylation on induction of CYP1A1 expression by AhR ligands as well. Our results indicate that differentiated HepaRG cell line appeared to be very good substitute for human liver in studies on xenobiotic metabolism by AhR regulated enzymes.

Downregulated Chibby in laryngeal squamous cell carcinoma with increased expression in laryngeal carcinoma Hep-2 cells.

Chibby (Cby) inhibits Wnt/β-catenin-mediated transcriptional activation by competing with Lef-1 (the transcription factor and target of β-catenin) to bind to β-catenin. This suggests that Cby could be a tumor suppressor protein. In the present study, we examined Cby expression in laryngeal squamous cell carcinoma (LSCC) and its function and mechanism in laryngeal carcinoma cell lines. Cby expression levels were investigated by immunohistochemistry in a panel of 36 LSCC patient cases. The expression of β-catenin, c-myc and cyclinD1 in Hep-2 were determined through RT-PCR and western blot analysis. Activity of Wnt/β-catenin signaling pathway after overexpression of Cby was measured by TCF/LEF luciferase reporter gene assay. Proliferation, clone forming ability, cell cycle distribution and cell apoptosis of Hep-2 cells were detected by MTT assay, plate colony forming assay, flow cytometry and TUNEL assay, respectively. This study showed that expression of Cby protein was strongly downregulated in LSCC tumor tissues in comparison to normal laryngeal mucosa samples. No significant correlation was found between the expression of Cby in tumor tissue and gender, age, clinical stage and tumor differentiation of laryngeal cancer patients. When Cby was overexpressed in Hep-2 cells, the expression of cyclin D1 was reduced and β-catenin activity was inhibited. Proliferation and plate colony forming assays revealed a significant inhibitory effect of Cby on growth and colony formation ability of Hep-2 cells after Cby overexpression in comparison to control and mock-infected cells. In addition, we also found that upregulated expression of Cby resulted in accumulation of numbers of cells in G0/G1 phase with concomitant decrease in S phase by cell cycle assay. TUNEL staining demonstrated that, compared with the control group, the rate of apoptosis in the plv-cs2.0-Cby group was significantly increased. Taken together, downregulation of Cby was observed in LSCC, but with no significant correlation to the clinicopathological features of LSCC patients. Overexpression of Cby effectively suppressed laryngeal carcinoma cell growth and promoted its apoptosis. A better understanding of the mechanisms of Cby gene activation in LSCC could provide potential novel therapeutic targets for human laryngeal carcinoma.

Antiproliferative effects of celecoxib in Hep-2 cells through telomerase inhibition and induction of apoptosis.

To investigate the effect of celecoxib on telomerase activity and apoptosis in a human laryngeal squamous carcinoma cell line (Hep-2 cells). The growth inhibition rate of Hep-2 cells in vitro was measured by MTT assay, and apoptosis by TUNEL assay and flow cytometry (FCM). The TRAP-ELISA method was used to determine telomerase activity in Hep-2 cells. The mRNA expression of human telomerase RNA component(hTR), human telomerase reverse transcriptase (hTERT) and human telomerase-associated protein(hTEP1) was determined by RT-PCR assay. Expression of Bax and Bcl-2 proteins was assessed by Western blotting. Celecoxib can inhibit proliferation and induce apoptosis in a dose- and time-dependent manner, repress telomerase activity, decrease hTERT mRNA and Bcl-2 protein expression and increase Bax protein expression, PGE2 had no effect on telomerase. Celecoxib had the antiproliferative and pro-apoptotic effect in Hep-2 cells. Apoptosis was accompanied by a decrease in telomerase activity which was directly correlated with hTERT mRNA and up-regulation of Bax/Bcl-2. Bcl-2 may thus play an important role in telomerase activity as well as apoptosis.

Effect of DJ-1 overexpression on the proliferation, apoptosis, invasion and migration of laryngeal squamous cell carcinoma SNU-46 cells through PI3K/AKT/mTOR.

The aim of the present study was to explore the effect of DJ-1-mediated PI3K/AKT/mTOR pathway on the proliferation, apoptosis, invasion, migration and other tumor biological characteristics of laryngeal squamous cell SNU-46, through stable transfection and overexpression of the DJ-1 gene. Retrovirus carrying DJ-1 gene was used to stabilize transfected human laryngeal squamous carcinoma SNU-46 cell line, and monoclonal cell line of stably overexpressed DJ-1 protein was screened out by G418. DJ-1 protein expression was determined by western blotting, and changes of p-AKT, p-mTOR and PTEN protein content were detected, followed by the detection of changes in proliferation, apoptosis, invasion, migration and other tumor biological characteristics of laryngeal squamous carcinoma cell line with stably transfected DJ-1 protein overexpression by flow cytometry, CCK-8 method and Transwell. We successfully constructed a laryngeal squamous carcinoma cell line of stably overexpressed DJ-1 protein and termed it SNU-46-DJ-1. After overexpression of DJ-1 protein, the levels of PTEN expression in laryngeal squamous cell SNU-46 decreased and p-AKT and p-mTOR protein expression levels increased. Compared to the untreated SNU-46 cells, the proliferation rate of SNU-46-DJ-1 cells increased (0.834±0.336 vs. 0.676±0.112; p<0.001); invasiveness was enhanced (165.7±13.6 vs. 100.0±17.4; p=0.001), the migration ability was enhanced (207.3±13.1vs.175.3±13.3; p=0.036), and the apoptosis rate decreased (3.533±5.167 vs. 16.397±5.447%; p=0.019). The overexpression of DJ-1 protein in laryngeal squamous carcinoma SNU-46 cells can accelerate proliferation rate, increase the invasion and migration capacity, and reduce apoptosis, by activating the PI3K/AKT/mTOR pathway.

PLGF inhibition impairs metastasis of larynx carcinoma through MMP3 downregulation.

Cancer neovascularization plays a key role in the metastasis of larynx carcinoma. However, the molecular mechanism for the neovascularization control in larynx carcinoma is poorly understood. Since placental growth factor (PLGF) has been reported to be involved in pathological angiogenesis, and since matrix metalloproteinases (MMPs) are essential for extracellular matrix degradation during neovascularization, here we were prompted to examine whether PLGF and MMPs may play a coordinate role in the metastasis of larynx carcinoma. Our data showed that the expression of PLGF and MMP3 strongly correlated in the larynx carcinoma in the patients, and significant higher levels of PLGF and MMP3 were detected in the larynx carcinoma from the patients with metastasis of the primary cancer. Thus, we used a human larynx carcinoma cell line, Hep-2, to examine whether expression of PLGF and MMP3 may affect each other. We found that overexpression of PLGF in Hep-2 cells increased expression of MMP3, while inhibition of PLGF in Hep-2 cells decreased expression of MMP3. However, neither overexpression, nor inhibition of MMP3 in Hep-2 cells affected the expression level of PLGF. These data suggest that PLGF may function upstream of MMP3 in larynx carcinoma cells. We then analyzed how PLGF affected MMP3. Application of a specific ERK1/2 inhibitor to PLGF-overexpressing Hep-2 cells substantially abolished the effect of PLGF on MMP3 activation, suggesting that PLGF may increase expression of MMP3 via ERK/MAPK signaling pathway. Since anti-PLGF was recently applied in clinical trials to inhibit cancer-related angiogenesis, here our data further demonstrate that inhibition of cancer neovascularization by anti-PLGF is mediated not only by direct effect on endothelial growth and capillary permeability, but also by indirect effect via MMP3 on the extracellular matrix degradation in larynx carcinoma.

Frequent hypermethylation of WNT pathway genes in laryngeal squamous cell carcinomas.

Aberrations in the function of the WNT signaling pathway have been recently implicated in the pathogenesis of head and neck cancer, and the hypermethylation of several WNT cascade inhibitors were shown to be useful in disease prognosis. However, the extent of deregulation of WNT pathway by DNA hypermethylation has not been studied in detail in laryngeal cancer so far. The aim of this study was to establish the frequency of methylation of WNT pathway negative regulators in laryngeal squamous cell carcinomas and evaluate its prognostic significance. Twenty-six laryngeal squamous cell carcinoma cell lines and samples obtained from twenty-eight primary laryngeal carcinoma patients were analyzed. The methylation status of DKK1, LKB1, PPP2R2B, RUNX3, SFRP1, SFRP2, and WIF-1 was assessed using the methylation-specific polymerase chain reaction. Frequent hypermethylation of DKK1, PPP2R2B, SFRP1, SFRP2, and WIF-1 was detected, and a high methylation index was usually observed. Half of the cell lines analyzed and seventy percent of primary laryngeal carcinoma cases were characterized by the methylation of at least four genes. The hypermethylation of PPP2R2B or WIF-1 was associated with longer survival in laryngeal carcinoma cell lines. Moreover, the concurrent methylation of PPP2R2B and SFRP1 differentiated primary from recurrent laryngeal carcinoma cell lines. Frequent hypermethylation of WNT pathway negative regulators is observed in laryngeal squamous cell carcinomas. The possible prognostic significance of the methylation of DKK1, PPP2R2B, and SFRP1 needs to be evaluated in further prospective studies.