Apoptosis Of CNE-2 Cells Research Articles

Salinomycin enhances radiotherapy sensitivity and reduces expressions of BIRC5 and NEIL2 in nasopharyngeal carcinoma.

The aim of this study was to investigate the effects of salinomycin (Sal) on expressions of baculoviral IAP repeat-containing 5 (BIRC5) and Nei endonuclease VIII-like 2 (NEIL2) and radiotherapy sensitivity of nasopharyngeal carcinoma (NPC). Human NPC CNE-2 cell lines were used as research objects in this study. Subsequently, the cells received intervention with Sal at different concentrations, radioactive rays at different doses and Sal combined with radioactive rays. The growth inhibition rate of CNE-2 cells was detected via methyl thiazolyl tetrazolium (MTT) assay. The dose-effect relations of Sal, radioactive rays and combination therapy with the inhibitory effect on CNE-2 cells were obtained. CNE-2 cells receiving intervention with Sal at an appropriate concentration or radioactive rays at an appropriate dose alone and Sal combined with radioactive rays were used as intervention groups (Sal group, Radiation group and Combination group). However, those added with an equal amount of DMSO were set as Control group. Next, the cycle, apoptosis and apoptotic morphology of CNE-2 cells were observed via flow cytometry and Hoechst assay, respectively. Moreover, the expressions of apoptosis-related proteins Caspase-3, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax), as well as BIRC5 and NEIL2 proteins in CNE-2 cells were determined using Western blotting. Under the intervention with Sal or radioactive rays alone, the growth inhibition rate of CNE-2 cells rose in a concentration/dose-dependent manner. With the increase in Sal concentration in combination therapy, the growth inhibition rate of CNE-2 cells significantly increased (p<0.05). Compared with Control group, Sal group, Radiation group, and Combination group exhibited remarkably lower colony formation rate, higher proportion of CNE-2 cells in the G2/M phase, enhanced apoptosis of CNE-2 cells with nuclear fragmentation, increased expressions of pro-apoptotic proteins Caspase-3 and Bax, decreased expression of anti-apoptotic protein Bcl-2, and lower protein expressions of BIRC5 and NEIL2 in cells (p<0.05). Compared with Radiation group, the Combination group had significantly decreased colony formation rate, increased proportion of CNE-2 cells in the G2/M phase, enhanced apoptosis of CNE-2 cells with more nuclear fragmentation and other apoptosis characteristics, increased expressions of pro-apoptotic proteins Caspase-3 and Bax, decreased expression of anti-apoptotic protein Bcl-2, and decreased protein expressions of BIRC5 and NEIL2 in cells (p<0.05). Sal enhances the radiotherapy sensitivity of NPC and reduces the protein expressions of BIRC5 and NEIL2 in cells.

Rac1: A potential radiosensitization target of human nasopharyngeal carcinoma CNE2 cells

Radiotherapy has a high cure rate for early nasopharyngeal carcinoma(NPC). However, the radiation resistance of poorly differentiated NPC cells impacts the effectiveness of treatment of early-stage NPC patients. Here, we explored the relationship between Ras-related C3 botulinum toxin substrate 1(Rac1) expression and NPC radiosensitivity. In vitro and in vivo studies revealed that upregulation of Rac1, when combined with X-ray treatment, increased growth inhibition and induced remarkable morphological changes and apoptosis in CNE2 cells. Furthermore, rupturing of the cell and nuclear membranes, degeneration of the cristae and significant swelling of the mitochondria were observed, which were consistent with the high apoptotic rate. The Rac1(+) cells exhibited approximately 50% more migration compared with that of the NC and Rac1(-) cells. The overexpression of Rac1 can increase the radiation sensitivity of NPC CNE2 cells, and the mechanism may be closely related to the oxidative damage of mitochondria. Rac1 might be a potential target for radiosensitization in poorly differentiated NPC.

A caffeic acid phenethyl ester analog inhibits the proliferation of nasopharyngeal carcinoma cells via targeting epidermal growth factor receptor.

A previous study reported that compound 5A, a caffeic acid phenethyl ester (CAPE) analog, exhibited obvious neuroprotective activity, in particular, compound 5A possessed higher stability and membrane permeability than CAPE. CAPE displays antitumour function; therefore, evaluating the antitumour effect of its analog with higher stability and membrane permeability is worthwhile. We first investigated the antitumour activity of compound 5A. We found that compound 5A significantly inhibited the proliferation of tumor cells and showed low cytotoxicity in normal cells. Furthermore, compound 5A was found to induce the cell cycle arrest and apoptosis of CNE2 cells. Through the prediction of SwissTargetPrediction and subsequent confirmation, epidermal growth factor receptor (EGFR) was identified as a target of compound 5A. Compound 5A also influenced the expression of genes downstream of EGFR in nasopharyngeal carcinoma (NPC) cells. Based on these findings, compound 5A inhibits the proliferation of NPC cells by targeting EGFR and may become a new candidate compound for NPC treatment.

MiR-34a Regulates Nasopharyngeal Carcinoma Radiosensitivity by Targeting SIRT1

Background/Aims:Nasopharyngeal carcinoma is a common head and neck cancer in South China and Southeast Asia. Radiotherapy is the standard treatment for nasopharyngeal carcinoma. Accumulating evidence showed that the expression of miR-34a was abnormal in nasopharyngeal carcinoma. Here, this study investigates the effect of miR-34a on radiosensitivity of nasopharyngeal carcinoma cells and explored the underlying mechanisms.Methods:Reverse transcription quantitative polymerase chain reaction was used to analyze the expression of miR-34a in nasopharyngeal carcinoma cell lines and NP69 cells. The effect of miR-34a on radiosensitivity of nasopharyngeal carcinoma (CNE-1 cells) was evaluated by Cell Counting Kit-8, flow cytometry, and Transwell migration assays following transfection with miR-34a mimic. Luciferase reporter assay was used to assess the target genes of miR-34a.Results:In this study, it revealed that miR-34a was downregulated, while silent information regulator 1 was upregulated in nasopharyngeal carcinoma cell lines. The overexpression of miR-34a enhanced radiation-induced proliferation and migration inhibition and apoptosis in CNE-1 cells. Bioinformatics, Luciferase reporter, reverse transcription quantitative polymerase chain reaction, and Western blotting assays indicated that silent information regulator 1 is a direct target of miR-34a in nasopharyngeal carcinoma cells. Knockdown of silent information regulator 1 enhanced radiosensitivity of nasopharyngeal carcinoma cells as evidenced by increasing proliferation and migration inhibition and apoptosis after radiation exposure.Conclusion:In summary, our results indicated that the overexpression of miR-34a enhanced radiosensitivity of nasopharyngeal carcinoma cells by targeting silent information regulator 1. Further studies are warranted to investigate the potential use of miR-34a in the clinical management and treatment prediction of patients with nasopharyngeal carcinoma.

Silencing vascular endothelial growth factor C increases the radiosensitivity in nasopharyngeal carcinoma CNE-2 cells.

Vascular endothelial growth factor C (VEGF-C) has been reported to be responsible for the lymphatic vessel density, tumor staging and lymph node metastasis, resulting in the failure of nasopharyngeal carcinoma (NPC) after radiotherapy. Therefore, the aim of this study was to explore the effects and the underlying mechanism of VEGF-C on the radiotherapy and in the human NPC cell lines CNE-2. In our study, VEGF-C silenced CNE-2 cells were stably established. Different small interfering VEGF-C (si-VEGFC) were transfected into CNE-2 cells and combined with 8 Gy X-ray. The proliferation, cloning ability, DNA damage, and apoptosis of CNE-2 cells were evaluated by counting kit-8 (CCK-8), colony-forming assay, comet assays, and flow cytometry, respectively. Moreover, the VEGFC knockdown involved signaling pathways in CNE-2 cells were predicted by polymerase chain reaction (PCR) array, and validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. Results demonstrated that silencing VEGF-C combined with radiation can significantly inhibit the proliferation and cloning ability, while increase the apoptosis and DNA damage of CNE-2 cells, thereby promote the radiosensitivity. Furthermore, the effects of silencing VEGF-C probably through activating the NF-kB signal pathway. In conclusion, the study demonstrated that VEGF-C may be a potential target to increase the radiosensitivity in NPC by activating NF-kB signaling.

MiR-155 promotes proliferation and inhibits apoptosis of nasopharyngeal carcinoma cells through targeting PTEN-PI3K/AKT pathway.

Nasopharyngeal carcinoma (NPC) is a polygenic hereditary disease, and the exact pathogenesis remains poorly understood. MiR-155 regulates the development and progression of several tumors. However, the role of MiR-155 in NPC has not been elucidated. The NPC cell line CNE2 was cultured in vitro and divided into control group, miR-155 mimics group, and miR-155 inhibitor group, followed by analysis of miR-155 expression by real-time PCR, cell proliferation by MTT assay, cell invasion by transwell chamber, Caspase3 activity, apoptosis of CNE2 cells by flow cytometry, and the expression of PTEN-PI3K/AKT signaling pathway by Western blot. Transfection of miR-155 mimics significantly up-regulated miR-155 expression, promoted the proliferation and invasion of CNE2 cells, inhibited Caspase 3 activity, and decreased cell apoptosis, and PTEN expression, as well as increased PI3K/AKT phosphorylation, compared with control group (p < 0.05). Transfection of miR-155 inhibitor inhibited the proliferation and invasion of CNE2 cells, increased Caspase 3 activity, cell apoptosis, and PTEN expression, as well as reduced PI3K/AKT phosphorylation. Compared with control group, the differences were statistically significant (p < 0.05). Up-regulation of miR-155 can promote the proliferation of NPC cells and inhibit cell apoptosis by targeting the PTEN-PI3K/AKT pathway, thereby participating in the development and invasion of NPC, indicating that it might be a potential novel target for treating NPC.

Mukonal Inhibits Cell Proliferation, Alters Mitochondrial Membrane Potential and Induces Apoptosis and Autophagy in Human CNE1 Nasopharyngeal Carcinoma Cells.

BackgroundNasopharyngeal carcinoma results in high patient morbidity and mortality, due to early metastasis, and toxicity due to chemotherapy. Mukonal is plant-derived carbazole alkaloid that has been used in traditional Chinese medicine to treat several types of cancer. This study aimed to investigate the effects of mukonal on cell proliferation, apoptosis, autophagy, and the mitochondrial membrane potential of nasopharyngeal carcinoma cells in vitro.Material/MethodsCNE1 human nasopharyngeal carcinoma cells and NP69 normal nasopharyngeal epithelial cells were cultured with and without treatment with increasing doses of mukonal. Cell viability was determined by the MTT assay. Fluorescence microscopy was used to detect reactive oxygen species (ROS), mitochondrial membrane potential, and the release of cytochrome C. Flow cytometry was used to examine changes in the cell cycle, electron microscopy examined cell autophagy, and Western blot was performed to measure levels of proteins associated with autophagy and apoptosis.ResultsMukonal had an antiproliferative effect on CNE1 cells, with an IC50 of 9 μM and there were effects of toxicity on normal NP69 cells. Mukonal triggered ROS-mediated changes in mitochondrial membrane potential which was also accompanied by the discharge of cytochrome C in the CNE1 cells. Mukonal activated autophagy and apoptosis in CNE1 cells, which was also associated with upregulation of the autophagy-related proteins, LC3 II and beclin-1, as well as apoptosis-associated proteins, Bax, cleaved caspase-3 and -9. Mukonal treatment also resulted in CNE1 cells cycle arrest at G2/M.ConclusionsMukonal inhibited the growth of human CNE1 nasopharyngeal carcinoma cells in vitro.

Synergistic Effects of Targeting Survivin and CDK1 on Nasopharyngeal Carcinoma &amp;lt;i&amp;gt;in Vitro&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;in Vivo&amp;lt;/i&amp;gt;

Background: To explore the impact of pU6-based tandem survivin and CDK1-specific short hairpin RNA on the biological behaviors of CNE-2 nasopharyngeal carcinoma cells in vitro and in vivo. Patients and Methods: The vectors of pU6-survivinshRNA, pU6-CDK1shRNA and pU6-survivinshRNA-CDK1shRNA were constructed and transfected into CNE-2 cells with Lipofectamine TM 2000, respectively. The mRNAs and proteins of CDK1 and survivin were determined by RT-PCR and Western blotting, accordingly. MTT assay was employed to evaluate the proliferation of CNE-2 cells, and flow cytometry was performed to determine the apoptosis of CNE-2 cells. The effects of interfering survivin and CDK1 on tumorigenesis were evaluated by tumor xenografts experiments. Results: Effective plasmids were successfully constructed knocking down survivin and/or CDK1. The proliferation inhibition of CNE-2 cells by pU6-survivinshRNA-CDK1shRNA (32.5%) was higher than that of by pU6-survivinshRNA (25.6%) and pU6-CDK1shRNA (15.6%), and apoptosis in CNE-2 cells simultaneously interfering survivin and CDK1 (15.2%) dramatically increased when compared to those of interfering survivin (5.4%) or CDK1 (4.7%) alone. Furthermore, simultaneously interfering survivin and CDK1 is more effective than interfering alone component in inhibiting tumor growth of fBalb/C nude mice xenografted with CNE-2 cells. Conclusion: The results altogether indicate that interfering survivin and CDK1simutaneously can produce synergistic effects of anti-nasopharyngeal carcinoma, which could be a potential therapeutic method.

Predictive Value of [18F]ML-10 PET/CT in Early Response Evaluation of Combination Radiotherapy with Cetuximab on Nasopharyngeal Carcinoma.

Apoptosis may be an indication of success therapy, and precise detection of apoptosis can provide instructional suggestions in the therapy management of malignant tumors. We used CNE-1 cell lines for in vitro experiments, and colony formation assay, CCK-8 assay, cell apoptosis analysis, and western blotting were performed. For in vivo experiments, subcutaneous xenotransplanted tumor models of CNE-1 in nude mice were established. Then, small animal positron emission tomography/X-ray computed tomography (PET/CT) images were acquired by tail intravenous injection of 2-(5-[18F]fluoropentyl)-2-methyl-malonic acid ([18F]ML-10) or 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) before and 24h and 48h after treatment. Moreover, expression of epidermal growth factor receptor (EGFR), Ki-67, Glut-1, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was examined by immunohistochemical examination. Tumor volumes of mice were recorded every 2days. In the presence of Cetuximab, the number of colonies of CNE-1 cells decreased significantly after irradiation at 1 and 2Gy. In addition, Cetuximab increased the radiation-induced cytotoxicity and apoptosis of CNE-1 cells. Mechanistic studies demonstrated that Cetuximab enhanced radiosensitivity by suppressing the EGFR/PI3-K/AKT pathway. In PET/CT imaging, the tumors showed clear uptake of [18F]ML-10 at 24h and 48h after combined treatment, and the value of tumor/muscle (T/M) and SUVmax (the max of standard uptake value) was significantly higher than those of the other three groups. The T/M of [18F]ML-10 uptake showed a positive correlation of 0.926 with the apoptosis index (P < 0.001). However, the uptake of [18F]FDG in tumors exhibited no trend among the four groups. The T/M of [18F]FDG revealed a positive correlation of 0.926 with Glut-1 intensity (P < 0.001). Our work revealed that Cetuximab could increase the radiosensitivity of CNE-1 cells both in vitro and in vivo. Apoptosis imaging with [18F]ML-10 PET/CT is a promising modality for application in the response prediction of nasopharyngeal carcinoma.

Curcumol induces cell cycle arrest and apoptosis by inhibiting IGF-1R/PI3K/Akt signaling pathway in human nasopharyngeal carcinoma CNE-2 cells.

Curcumol has been proved to possess antitumor effects in vivo and in vitro in several cancers. Previously, we have found that curcumol induced apoptosis in CNE-2 cells, but its underlying mechanism has not yet been studied well. Recently, our team clarified that curcumol inhibited colorectal cancer cells' growth partially through insulin-like growth factor 1 receptor (IGF-1R) pathway. Given the key importance of IGF-1R pathway in tumorigenesis, we want to explore whether curcumol effects on nasopharyngeal carcinoma (NPC) cells relates to IGF-1R and its downstream pathway inactivation. In this study, we found that curcumol inhibited IGF-1R and p-Akt expression in a dose- and time-dependent way. In addition, it also regulated their downstream GSK-3β's activity in CNE-2 cells, which further triggering alterations in the expression of cycle- and apoptosis-related molecules, and then leading to G0/G1-phase arrest and apoptosis. Moreover, curcumol's effect on CNE-2 cells was partly eliminated by IGF-1R's agonist IGF-1. In conclusion, our findings indicated that the inhibitory effect of curcumol on proliferation of NPC cells is related to the inhibition of IGF-1R and its downstream PI3K/Akt/GSK-3β pathway.

In vitro study of joint intervention of E-cad and Bmi-1 mediated by transcription activator-like effector nuclease in nasopharyngeal carcinoma

To explore the effect of intervention of E-cadherin (E-cad) and B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) mediated by transcription activator-like effector nuclease (TALEN) on the biological behaviors of nasopharyngeal carcinoma cells. Methods: Multi-locus gene targeting vectors pUC-DS1-CMV-E-cad-2A-Neo-DS2 and pUC-DS1-Bmi-1 shRNA-Zeo-DS2 were constructed, and the E-cad and Bmi-1 targeting vectors were transferred with TALEN plasmids to CNE-2 cells individually or simultaneously. The integration of target genes were detected by PCR, the expressions of E-cad and Bmi-1 were detected by Western blot. The changes of cell proliferation were detected by cell counting kit-8 (CCK-8) assay. The cell cycle and apoptosis were detected by flow cytometry. The cell migration and invasion were detected by Transwell assay. Results: The E-cad and Bmi-1 shRNA expression elements were successfully integrated into the genome of CNE-2 cells, the protein expression level of E-cad was up-regulated, and the protein expression level of Bmi-1 was down-regulated. The intervention of E-cad and Bmi-1 didn't affect the proliferation, cell cycle and apoptosis of CNE-2 cells, but it significantly inhibited the migration and invasion ability of CNE-2 cells. Furthermore, the intervention of E-cad and Bmi-1 together significantly inhibited the migration ability of nasopharyngeal carcinoma cells compared with the intervention of E-cad or Bmi-1 alone (all P<0.01). Conclusion: The joint intervention of E-cad and Bmi-1 mediated by TALEN can effectively inhibit the migration and invasion of nasopharyngeal carcinoma cells in vitro, which may lay the preliminary experimental basis for gene therapy of human cancer.

Construction, Expression, and Characterization of rSEA-EGF and In Vitro Evaluation of its Antitumor Activity Against Nasopharyngeal Cancer.

Staphylococcal enterotoxin A is well known as a superantigen and able to be used for cancer immunotherapy. In this study, recombinant Staphylococcal enterotoxin A was genetically conjugated to epidermal growth factor to produce a chimeric protein recombinant Staphylococcal enterotoxin A–epidermal growth factor expressed in Escherichia coli. The recombinant Staphylococcal enterotoxin A–epidermal growth factor protein was purified using Strep-Tactin affinity chromatography and Endotoxin Removal Resin and identified by sodium dodecyl sulfate-polyacrylamide gel electropheresis and liquid chromatography-tandem mass spectrometry analysis. Furthermore, in vitro experiments showed purified recombinant Staphylococcal enterotoxin A–epidermal growth factor could successfully bind to the human nasopharyngeal carcinoma cell line CNE2, significantly promote the proliferation of human peripheral blood mononuclear cells, and enhance the secretion of several cytokines that have broad antitumor activities, such as interferon-γ, tumor necrosis factor-α, and interleukin-2 . Importantly, recombinant Staphylococcal enterotoxin A–epidermal growth factor significantly inhibited proliferation of CNE2 cells and promoted apoptosis in CNE2 cells when cocultured with peripheral blood mononuclear cells. Finally, both the binding of recombinant Staphylococcal enterotoxin A–epidermal growth factor and the toxicity of recombinant Staphylococcal enterotoxin A–epidermal growth factor-activated peripheral blood mononuclear cells were demonstrated as specific and only effective on high epidermal growth factor receptor-expressing cell lines. In all, our work suggests that recombinant Staphylococcal enterotoxin A–epidermal growth factor serves as a promising novel immunotherapeutic agent. More in vivo and in vitro studies are needed to verify its antitumor potency, as well as investigate the underlying mechanisms in cancer immunotherapy.

Low concentration of formononetin promotes proliferation of estrogen receptor-positive cells through an ERα-miR-375-PTEN-ERK1/2-bcl-2 pathway.

A low dose of formononetin accelerates the proliferation of nasopharyngeal carcinoma cells in vitro; however, the underlying mechanism remains unknown. Here, we investigated the molecular mechanism of formononetin in CNE2 cell proliferation. CNE2 cells were treated with 0 to 1 μM formononetin. To inhibit mitogen activated protein kinase / extracellular regulate kinase (MAPK/ERK) kinase (MEK) and microRNA (miR)-375, cells were pretreated with either PD98059 or a miR-375 inhibitor, respectively, followed by co-treatment with formononetin (0.3 μM) plus an inhibitor. Female rats were ovariectomized (OVX), and some OVX rats received formononetin or estrogen (E2) injections. Sham operated animals were used as controls. Compared to control, 0.3 μM formononetin accelerated proliferation and decreased late apoptosis of CNE2 cells. However, formononetin-induced pro-growth and anti-apoptosis activity was abolished by PD98059 and the miR-375 inhibitor. In addition, 0.1 and 0.3 μM formononetin significantly increased estrogen receptor-α (ERα) and bcl-2, but decreased protein-phosphatase and tensin homologue (PTEN) protein expression, all of which was reversed by the miR-375 inhibitor. Additionally, formononetin treatment resulted in a transient upregulation of phosphorylated (p)-ERK1/2. In vivo studies indicated that formononetin significantly increased endometrium thickness and down-regulated ERα expression in OVX rats. Taken together, our study demonstrates that a low concentration of formononetin can promote growth of CNE2 cells and uterine tissues, possibly through regulating the ERα-miR-375-PTEN-ERK1/2-bcl-2 signaling pathway.

MicroRNA-15a Inhibits Proliferation and Induces Apoptosis in CNE1 Nasopharyngeal Carcinoma Cells.

Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer, frequently occurring in Southeast Asia and Southern China. Several microRNAs (miRNAs) have been shown to have an inhibitive effect on NPC, while the effect of miR-15a on NPC remains unclear. Thus, our study aimed to investigate the potential effect of miR-15a on NPC cell proliferation, apoptosis, and possible functional mechanism. Human NPC CNE1 cells were transfected with miR-15a mimics, miR-15a inhibitors, or a control. Afterward, cell viability and apoptosis were assayed by using CCK-8, BrdU assay, and flow cytometry. Moreover, Western blot was used to detect the expression changes of proliferation and apoptosis of related proteins. As a result, miR-15a overexpression significantly reduced cell proliferation (p < 0.01 or p < 0.001) and induced cell apoptosis (p < 0.001), while miR-15a suppression got the opposite result for cell proliferation and apoptosis. In addition, miR-15a overexpression upregulated the protein levels of p27, GSK-3β, Bax, procaspase 3, and active caspase 3, whereas miR-15a suppression downregulated these proteins. The protein level of p21 was not significantly regulated by miR-15a overexpression or suppression. These results indicated that miR-15a played a role for inhibition of proliferation and induction of apoptosis in CNE1 cells.

Silencing Op18/stathmin by RNA Interference Promotes the Sensitivity of Nasopharyngeal Carcinoma Cells to Taxol and High-Grade Differentiation of Xenografted Tumours in Nude Mice.

Nasopharyngeal carcinoma (NPC) is a refractory tumour, and chemotherapy is one of the primary treatment modalities. Oncoprotein 18 (Op18)/stathmin is a conserved small cytosolic phosphoprotein and highly expressed in tumours, which plays a vital role in maintaining the malignant phenotype of tumours. Taxol is a clinically widely used chemotherapeutic agent for a broad range of taxol-resistant tumours. This study showed that Op18/stathmin silencing by RNA interference (RNAi) combined taxol cooperatively improved cellular apoptosis in CNE1 cells mainly via initiating endogenous death receptor pathway, impaired the capabilities of cellular proliferation and cellular migration and down-regulated the half maximal inhibitory concentration (IC50 ) of taxol, meanwhile decreased the expression of the upstream extracellular regulated kinase 1 (ERK1) in vitro. Evidence also showed that taxol cytotoxicity was markedly augmented for Op18/stathmin RNAi in other NPC cells. In vivo animal experiments have demonstrated that early combination of Op18/stathmin silencing and taxol evidently inhibited tumourigenicity of CNE1 cells and growth of xenografted tumours in nude mice. Remarkably, silencing Op18/stathmin by RNAi still promoted transformation of late-stage CNE1 cells in NPC-xenografted tumours from moderately to highly differentiated and inhibited the pleiotropic cytokine interleukin-10 (IL-10) autocrine by transplanted tumours. These findings suggest that silencing Op18/stathmin by RNAi promotes chemosensitization of NPC to taxol and reverses malignant phenotypes of NPC, which provides a new clue for treating drug-resistant tumours.

Dihydroartemisinin inhibits cell proliferation by induced G1 arrest and apoptosis in human nasopharyngealcarcinoma cells.

Dihydroartemisinin (DHA) exhibits anticancer activity in a number of human cancer cells. However, it is still unknown whether DHA has anticancer effect on nasopharyngeal cancer (NPC) cells. To investigate the anticancer activity of DHA on CNE-2 cells. Cell cycleand invasion assay were used to detect the effect of DHA on CNE-2 cells. Protein molecular differences were examined by Western blot. DHA strongly inhibited cell proliferation by induced cell cycle G1 arrest and apoptosis in CNE-2 cells. In addition, cell motility, invasion, and colony formation were suppressed by DHA. DHA shows significant anticancer effects on human NPC cells, and may be a preventive and therapeutic agent against NPC.

Cinnamic Acid (CINN) Induces Apoptosis and Proliferation in Human Nasopharyngeal Carcinoma Cells

Background/Aims: CINN is the main ingredient of the traditional Chinese medicine cinnamon. The purpose of the present study was to investigate the effects of CINN on the proliferation and apoptosis of NPC cells and to elucidate the underlying molecular mechanisms. Materials and Methods: CNE2 human NPC cells were treated with various CINN concentrations. The effects of CINN on the proliferation and apoptosis of CNE2 NPC cells were examined using the MTT assay and flow cytometric analysis. Additionally, western blotting was performed to analyze the expression of a number of cell cycle- and apoptosis-related proteins. Results: The proliferation of CNE2 cells was significantly inhibited after treatment with different CINN concentrations for various lengths of time. The inhibitory effect of CINN was concentration-and time-dependent. Flow cytometric analysis showed that 2 mmol/L CINN displayed a significant apoptosis-inducing effect. The western blot analysis results showed that KLF6, Fas-L, Bax, P53 and caspase-3 protein expression was drastically increased in the CNE2 cells after treatment with 2 mmol/L CINN, whereas Bcl-2 and cyclin D1 protein expression was markedly reduced. Conclusion: CINN inhibits the proliferation and induces the apoptosis of CNE2 cells. Therefore, CINN possesses a potential anti-tumor effect.

Puquitinib mesylate (XC-302) induces autophagy via inhibiting the PI3K/AKT/mTOR signaling pathway in nasopharyngeal cancer cells.

There are numerous studies that demonstrate the anti-neoplastic activity of phosphatidylinositol 3-kinase (PI3K) inhibitors and the mechanisms of inducing autophagy in cancer cells. The new anticancer drug puquitinib mesylate (XC-302) is a molecular-targeted drug, which suppresses the activity of PI3K directly. However, it remains unclear whether XC-302 can develop an antitumor effect by inducing autophagy in naso-pharyngeal cancer cells. The MTT assay was used to study the anti-proliferative effects of XC-302. Subsequently, autophagy was determined by monodansylcadaverine (MDC) staining, punctate localization of green fluorescent protein (GFP)-light chain 3 (LC3), LC3 protein blotting and electron microscopy. The expression levels of beclin 1, p62, protein kinase B (AKT), phospho (p)-AKT, mechanistic target of rapamycin (mTOR) and p-mTOR in XC-302-induced autophagy were detected. Autophagy inhibition was assayed by 3-methyladenine (3-MA) or small interfering RNA (siRNA) silencing of beclin 1. XC-302 inhibited the viability of CNE-2 in a dose-dependent manner and the IC50 of 72 h was 5.2 µmol/l. After cells were exposed to XC-302 for 24 h, MDC-labeled autophagolysosomes were evident in CNE-2 cells by fluorescence microscope. Autophagosomes and autolysosomes were identified by transmission electron microscopy. Following transfection with GFP-LC3, XC-302 induced a significant accumulation of GFP-LC3, as monitored by a confocal microscope, which was reduced by 3-MA. XC-302 induced the formation of LC3-II, increased beclin 1 levels and decreased the expression of p62. Additionally, the expression levels of p-AKT and p-mTOR were reduced with the elevation of XC-302. Knockdown of beclin 1 with siRNA or co-treatment with 3-MA enhanced significantly the survival of CNE-2 and promoted the ability of clone formation. XC-302 also induced apoptosis in CNE-2, and when autophagy was inhibited by 3-MA, the apoptosis rate was decreased. The present data provides the evidence that XC-302 can induce autophagy in CNE-2, which promotes the program of cell death and inhibits the PI3K/AKT/mTOR signaling pathway. Furthermore, XC-302 also promoted apoptosis in CNE-2 cells, which could be reduced when autophagy was suppressed, meaning that autophagy may interact with apoptosis to induce cell death.

The natural compound gambogic acid radiosensitizes nasopharyngeal carcinoma cells under hypoxic conditions.

Hypoxia is an important factor that causes decreased local disease control as well as increased distant metastases and resistance to radiotherapy in patients with advanced nasopharyngeal carcinoma (NPC). Gambogic acid (GA), the major active ingredient of gamboge, exerts antitumor effects in vitro and in vivo. However, the molecular mechanism by which GA inhibits tumor radioresistance remains unclear. The present study aimed to investigate the radiosensitizing effects of GA on NPC and explore the underlying mechanisms. CNE-1 and CNE-2 cells exposed to hypoxia and radiation were treated with GA at different concentrations. CCK-8 assay, clonogenic assay, and flow cytometry were performed to analyze cell proliferation, colony formation, apoptosis, and cell cycle. The expression levels of hypoxia-inducible factor-1α (HIF-1α), Bcl-2, Bax, caspase-3, cyclin B1/p-cdc2 and γ-H2AX were assessed using Western blot and/or immunofluorescence analysis. Results of the CCK-8 assay, clonogenic assay, and flow cytometry showed that treatment of NPC cells with growth-suppressive concentrations of GA resulted in G2/M phase arrest and apoptosis. Western blot analysis demonstrated that GA-induced cell cycle arrest and apoptosis in CNE-2 cells was associated with upregulated expression of caspase-3 and Bax and downregulated expression of Bcl-2 and cyclin B1/p-cdc2 in hypoxia. Treatment with GA markedly decreased the expression of HIF-1α under hypoxic conditions. The results of this study suggest that GA efficiently radiosensitizes NPC cells and the effect may be significant in hypoxic conditions.

Sodium selenite (Na2SeO3) induces apoptosis through the mitochondrial pathway in CNE-2 nasopharyngeal carcinoma cells.

This study investigated the effect of sodium selenite (Na2SeO3) on proliferation, cell cycle, apoptosis as well as the underlying mechanism in CNE-2 nasopharyngeal carcinoma (NPC) cells. The CNE-2 cell line was treated with different concentrations of Na2SeO3, and the effects of Na2SeO3 on cell viability and proliferation were evaluated using Cell Counting kit-8 (CCK-8) assay. Cellular apoptosis and cell cycle were evaluated by flow cytometry following Annexin V‑FITC/PI double staining and PI single staining respectively; nuclei morphology stained with DAPI and Hoechst 333258 was observed under a fluorescence microscope, while DNA fragmentation was detected by agarose gel electrophoresis. The mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were analyzed using fluorescent staining assays. Expression of Bcl-XL, Bax, Bak, and caspase-3 activation were examined by western blotting. The results showed that Na2SeO3 inhibited proliferation and induced apoptosis of CNE-2 cells in a dose- and time-dependent manner. Na2SeO3 at low concentrations induced cell cycle arrest at S phase, while high concentrations of Na2SeO3 induced cell cycle arrest at G0/G1 phase. Furthermore, Na2SeO3 increased ROS level and decreased MMP, upregulated caspase-3 activity and the expression of Bak and Bax but simultaneously downregulated Bcl-XL. In conclusion, our studies demonstrated that Na2SeO3 had significant anti-proliferative and apoptosis-inducing effects via arresting cell cycle and regulating mitochondria-mediated intrinsic caspase pathway in CNE-2 NPC cells, suggesting that Na2SeO3 might have therapeutic potentials in the treatment of NPC.