Human Laryngeal Hep-2 Cells Research Articles

Effects of interleukin-17 on human laryngeal carcinoma Hep-2 cells

Objective To investigate the effects of interleukin-17 (IL-17) on the cell proliferation, apoptosis and migration of human laryngeal carcinoma Hep-2 cells. Methods IL-17 was transiently transfected into Hep-2 cells, and at the same time empty vector group (pEGFP-N1) and normal control group were set up. The efficiency of transfection was evaluated by fluorescence microscope, and the mRNA and protein expressions of IL-17 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The proliferation of cells was detected by methyl thiazolyl tetrazolium (MTT) method, and the apoptosis was detected by flow cytometry. The migration ability was detected by wound-healing assay and Transwell assay. Results Hep-2 cells transfected with empty vector pEGFP-N1 and IL-17 showed green fluorescence under the fluorescence microscope. Hep-2 cells expressed IL-17 at both mRNA and protein levels after transfection with IL-17. Compared with the normal control group, the proliferation of IL-17 transfected Hep-2 cells was significantly inhibited after 48 h transfection (0.34±0.03 vs. 0.46±0.04, P=0.006). The apoptotic rate of IL-17 transfected cells was higher than that of normal control group (26.80%±0.80% vs. 2.90%±0.31%, P=0.000). According to the wound-healing assay, compared with the normal control group, the scratch width of IL-17 transfected cells was significantly greater (1.59±0.01 vs. 1.36±0.01, P=0.000). Transwell migration experiment showed that the migration of IL-17 transfected cells was significantly lower than that of the normal control group (26.33±2.08 vs. 49.33±1.53, P=0.000). Conclusion IL-17 can inhibit the proliferation of human laryngeal carcinoma Hep-2 cells, reduce their migration ability and enhance their apoptosis ability. Therefore, IL-17 may inhibit the occurrence and development of laryngeal carcinoma through a variety of mechanisms. Key words: Interleukin-17; Laryngeal neoplasms; Cell proliferation; Apoptosis; Cell movement

Inhibitory effect of Jab1-specific shRNA on the progression of human laryngeal carcinoma xenografts nude mice

To evaluate the antitumour efficacy of shRNA plasmid specifically targeting Jab1 gene. The nude mouse tumor model was made by subcutaneous injection of human laryngeal carcinoma Hep-2 cells. The tumor growth was monitored after intratumoral injection of pJab1, pKB plasmids and saline. Jab1 and p27 expressions in tumour tissues were examined by immunohistochemistry staining and RT-PCR. Mean volume of the pJab1-treated tumors was (267.60 ± 88.19) mm(3), significantly less than that of tumors treated with pKB plasmids (832.20 ± 140.39) mm(3) or saline (895.40 ± 145.93) mm(3) (F = 36.73, P < 0.001). Immunohistochemistry showed that the expression of Jab1 protein was significantly reduced in the pJab1-treated group (32.40% ± 5.59%) compared to the control groups, whereas the expression rate of p27 protein in the pJab1 group (76.80% ± 6.30%) was significantly increased compared to the control groups (P < 0.001). The down regulation of Jab1 protein by pJab1 plasmid was consistent with mRNA expression confirmed by RT-PCR. The level of Jab1 mRNA level in the pJab1-treated group (0.65 ± 0.03) was significantly lower than the control groups (F = 558.00, P < 0.001), however, p27 mRNA, was 0.80 ± 0.02, had no significant alteration (F = 1.52,P > 0.05). The pJab1 plasmid results in downregulation of Jab1 in an xenograft tumour model of human laryngeal carcinoma Hep-2 cells and significantly inhibits the tumour growth in vivo. This suggests that pJab1 plasmid specifically targeting Jab1 gene expression could be an effective therapy for human laryngeal carcinoma.

Anti-Adhesive Activities of Flavan-3-ols and Proanthocyanidins in the Interaction of Group A-Streptococci and Human Epithelial Cells

Bacterial adhesion to epithelial cells is a key step in infections, allowing subsequent colonization, invasion and internalization of pathogens into tissues. Anti-adhesive agents are therefore potential prophylactic tools against bacterial infections. The range of anti-adhesive compounds is largely confined to carbohydrate analogues. Tannins are generously recognized as potent antimicrobials, but little data exist on their anti-adherence potency. Using a model for mucosal pathogenesis with labeled group A-streptococci (GAS) and human laryngeal HEp-2 cells, a series of flavan-3-ols (epicatechin, epigallocatechin, epigallocatechin-3-O-gallate) and highly purified and chemically characterized proanthocyanidin samples including procyanidins based on epicatechin, catechin or ‘mixed’ constituent flavanyl units, prodelphinidins made up of (epi)gallocatechin monomeric unts as well as oligomers possessing A-type units in their molecules was evaluated for anti-adhesive effects. Reduced microbial adherence was observed exclusively for prodelphinidins, suggesting that pyrogallol-type elements, i.e., (epi)gallocatechin units are important structural features. This is the first report on structure-activity relationships regarding the anti-adhesive potency of proanthocyanidins. In addition, the structures of the first chemically defined proanthocyanidins from Pelargonium sidoides are disclosed.

Molecular pathways in the chemosensitization of cisplatin by quercetin in human head and neck cancer

The aim of this study was to develop novel and less toxic therapy for human head and neck squamous cell carcinoma (HNSCCs) and to investigate the mechanism of quercetin-induced apoptosis in human laryngeal HeP2 cells and its effect on cisplatin induced apoptosis. Priming the cells with quercetin (40 ?M) increased the apoptosis induced by cisplatin alone from 18.7% to 42.2% in HeP2 cells. Quercetin induced apoptosis via inhibition of Akt/PKB phosphorylation, an upstream kinase of pro-survival protein kinase cascade. Inhibition of Akt phosphorylation was coupled with a significant decrease of anti-apoptotic Bcl-2 and Bcl-XL. Quercetin caused a downregulation of Cu-Zn Superoxide Dismutase which perhaps led to an increase of reactive oxidative stress (ROS). The decrease of Bcl-2 and Bcl-XL along with this oxidative stress caused release of mitochondrial cytochrome c into the cytosol and subsequent induction of pro-caspase-9 processing. Inhibition of heat shock proteins may be another mechanism for the pro-apoptotic activity of quercetin. Cisplatin induced apoptosis appears to be partly due to induction of JNK activity which leads to the activation of endonucleases. Increased JNK activity led to increased phosphorylation of c-Fos. Cisplatin additionally appears to induce apoptosis by downregulating the enzyme Nitric Oxide Synthase (NOS). Cisplatin also acts by increasing pro-apoptotic Bax concentration in the cells thereby leading to caspase-9 activation via the mitochondrial pathway. These results support the fact that quercetin and cisplatin act by separate pathways and demonstrate interactions between the pathways that result in synergistic actions. Possibly of greater potential value is the interaction of a conventional cytotoxic drug (cisplatin) and a non-toxic chemopreventive agent (quercetin) thereby allowing the use of less toxic doses of chemotherapy for treatment of HNSCCs.

Purification of a 20 kDa phosphoprotein from epithelial cells and identification as a myosin light chain Phosphorylation induced by enteropathogenic Escherichia coli and phorbol ester

Previous studies on the mechanism of enteropathogenic Escherichia coli (EPEC) infection have revealed an increase in the phosphorylation state of a number of proteins in human laryngeal HEp-2 cells. The most prominent was an acidic phosphoprotein(s) of M r 20–21 kDa. The present study reports: (a) a simple method for purification of phosphorylated 20 kDa protein: (b) identification of the 20 kDa phosphoprotein as myosin light chain; and (c) that the phorbol ester. TPA, also increased the phosphorylation of the 20 kDa myosin light chain. In contrast to the effects of EPEC, TPA stimulation resulted in the dissociation of myosin from the cytoskeleton to the cytosol.