Nasopharyngeal Carcinoma Cell Lines HONE1 Research Articles

Effects of biological clock gene BMAL1 and hypoxia-inducible factor HIF-1α on proliferation, migration and radiotherapy sensitivity of nasopharyngeal carcinoma cells HONE1

Objective To understand the effects of clock gene BMAL1 and HIF-1α(Hypoxia inducible factor-1α) on proliferation, migration and sensitivity to radiotherapy of nasopharyngeal carcinoma cells HONE1.At the same time, whether the biological clock gene BMAL1 can affect the expression of HIF-1α protein was investigated.It will lay the foundation for further study on the correlation between clock gene BMAL1 and HIF pathway.Methods BMAL1 gene overexpression and interference lentivirus and HIF-1α gene interference lentivirus were constructed respectively, and were transfected into nasopharyngeal carcinoma cells HONE1. Western blot was used to verify the establishment of overexpressed and knockdown BMAL1 cell lines and HIF-1α gene knockdown cell line, and to investigate the expression of HIF-1α protein in overexpressed and knockdown BMAL1 cell lines.CCK-8 cell proliferation test and scratch test were used to analyze the proliferation and migration ability of cells.Cell apoptosis after radiotherapy was analyzed by flow cytometry.The effects of BMAL1 and HIF-1α on the sensitivity of HONE1 radiotherapy in nasopharyngeal carcinoma cells after X-ray irradiation at different doses (0Gy, 2Gy, 4Gy, 6Gy) were detected by clone formation assay.Results The overexpression of BMAL1 gene and lentivirus interference were constructed to effectively up regulate and down regulate the expression of BMAL1 protein in nasopharyngeal carcinoma cells HONE1.Meanwhile, HIF-1α gene interference lentivirus was constructed to effectively down-regulate the expression of HIF-1α protein in nasopharyngeal carcinoma cell line HONE1, and successfully screen out stable nasopharyngeal carcinoma cell lines.Western blot results showed that overexpression of BMAL1 gene could inhibit the expression of HIF-1α protein in HONE1 of nasopharyngeal carcinoma cells, while knockdown of BMAL1 gene promoted the expression of HIF-1α protein in HONE1 of nasopharyngeal carcinoma cells(P < 0.05).CCK-8 cell proliferation and scratch test showed that overexpression of BMAL1 gene or knockdown of HIF-1α gene could inhibit the proliferation and migration of HONE1 cells (P < 0.05).Flow cytometry results showed that after 8Gy irradiation for 72 h, the apoptosis rate of BMALl gene overexpression group was higher than that of the overexpression control group, similarly, the apoptosis rate of HIF-1α gene knockdown group was higher than that of the knockdown control group (P < 0.05).After X-ray irradiation at different doses (0Gy, 2Gy, 4Gy, 6Gy), clon-formation experiment showed that the clon-formation rate and cell survival fraction of BMALl overexpression group or HIF-1α knockdown group were lower than those of negative control group (P < 0.05).Sigmaplot analysis showed that the D0, Dq and SF2 of the BMAL1 overexpression group or HIF-1α knockdown group were lower than those of the negative control group, and the radiosensitization ratios were 1.381 and 1.063, respectively.ConclusionOverexpression of BMAL1 gene can inhibit the proliferation and migration of nasopharyngeal carcinoma cell line HONE1, increase apoptosis after radiotherapy and improve radiosensitivity.Knock down HIF-1α Gene can inhibit the proliferation and migration of nasopharyngeal carcinoma cell line HONE1, increase apoptosis after radiotherapy and improve radiosensitivity.In nasopharyngeal carcinoma cells HONE1, overexpression of BMAL1 gene can inhibit the expression of HIF-1α protein while knockdown of BMAL1 gene can promote the expression of HIF-1α protein.

MiRNA profiling of human nasopharyngeal carcinoma cell lines HONE1 and CNE2 after X-ray therapy.

Radiotherapy is the main treatment for nasopharyngeal carcinoma. The radioresistance mechanism of cells is related to miRNAs. To investigate the miRNA profiling of HONE1 and CNE2 after X-ray therapy. The HONE1 and CNE2 cells were treated with X-ray at 4 Gy, 8 Gy, 16 Gy, and 20 Gy doses. The cell lines CNE2 with the best therapy effects and HONE1 with the worst therapy effects were screened out. Apoptosis and cell viability were detected with flow cytometry and Cell Counting Kit-8 (CCK-8). High-throughput sequencing was performed. A miRNA library was constructed. The miRNA annotation expression distribution, family prediction and target gene interaction, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted. The 24-hour 20 Gy dose X-rays were selected as the optimal therapy conditions. The CNE2_C, CNE2_M, HONE1_C and HONE1_M miRNAs accounted for 26.5%, 31.7%, 21.3%, and 22.9% of the Cleandata reads count, respectively, and the contents of rRNAs accounted for 24.9%, 14.7%, 25.1%, and 25.1% of the Cleandata reads count, respectively. The miRNAs with differential expression between the HONE1 and CNE2 cell lines including hsa-miR-21-5p, hsa-let-7a-5p, hsa-miR-125a-5p, hsa-miR-26a-5p, hsa-let-7f-5p, hsa-miR-20a-5p, and hsa-miR-24a-3p. There were also differentially expressed miRNAs in HONE1_C vs. HONE1_M, such as hsa-miR-21-5p and hsa-let-7i-5p. The differentially expressed miRNA in CNE2_C vs. CNE2_M was hsa-miR-148b-3p. The Gene Ontology analysis showed that the differentially expressed miRNA interacting genes in HONE1_M vs. CNE2_M were mainly enriched in biological process such as negative and positive regulation of transcription from RNA polymerase II promoter, cellular component such as cytosol and molecular function such as protein binding factor. The KEGG pathway analysis revealed that the differentially expressed miRNA interacting genes in HONE1_M vs. CNE2_M were enriched in the cancer-related pathways, such as pathways in cancer, MAPK signaling pathway and Wnt signaling pathway. Twelve miRNAs and 9 genes which contribute to X-ray radiation resistance were identified. Among those with differential expression between the HONE1 and CNE2 cell lines, which played a regulatory role in multiple pathways, were hsa-miR-20a-5p, hsa-let-7a-5p, hsa-let-7f5p, hsa-let-7i-5p, hsa-miR-30e-5p, hsa-miR-148b-3p, and hsa-miR-200c-3p. The corresponding genes were MAPK1, SOS1, TGFBR1, TGFBR2, TP53, CASP3, CCNE2, PTEN, and CDK2.

Effect of miR-25 on Proliferation of Nasopharyngeal Carcinoma Cells through Wnt/β-Catenin Signaling Pathway.

Objective To investigate the biological role and potential mechanism of miR-25 in nasopharyngeal carcinoma. Methods The expression of miR-25 in nasopharyngeal carcinoma cell lines was detected by qRT-PCR. The effect of inhibition of miR-25 expression on the proliferative activity of nasopharyngeal carcinoma cell line HONE-1 was examined by CCK-8 method. Flow cytometry was used to detect the effect of miR-25 expression inhibition on the apoptosis rate of nasopharyngeal carcinoma cell line HONE-1. The miRNA target gene prediction site TargetScan predicts the target protein action site of miR-124 and verifies whether miR-25 interacts with the target by luciferase activity assay, qPCR, and Western experiments. The miR-25 inhibitor and target egg gene expression plasmids were cotransfected into HONE-1 cells for rescue experiments to investigate whether miR-25 inhibits proliferation of nasopharyngeal carcinoma cells by target genes. At the same time, qRT-PCR was used to detect the mRNA expression levels of Wnt/β-catenin pathway key proteins TCF4, c-Myc, and Cyclin D1 in different transfected cells. Results miR-25 expression was upregulated in nasopharyngeal carcinoma cell lines. Functional studies showed that inhibition of miR-25 expression significantly inhibited the proliferation of nasopharyngeal carcinoma cell line HONE-1 (p < 0.05). Inhibition of miR-25 expression by flow cytometry significantly promoted apoptosis (p < 0.05). Detection of dual luciferase activity indicated that DKK3 is a direct target site for miR-25. Western blots showed that inhibition of miR-25 significantly upregulated DKK3 mRNA and protein levels. Supplementation with DKK3 significantly attenuated the inhibitory effect of miR-25 on the proliferation of nasopharyngeal carcinoma cell line HONE-1 (p < 0.05). qRT-PCR found that mRNA levels of TCF4, c-Myc, and Cyclin D1 were significantly upregulated in miR-25-transfected cells compared to control transfection. QRT PCR showed that the mRNA and protein levels of Tcf4, c-myc, and Cyclin D1 were significantly upregulated in miR-25 overexpression-transfected cells. Conclusion Inhibition of miR-25 expression promotes DKK3 gene expression, and inactivation of Wnt/β-catenin signaling pathway inhibits proliferation and promotes apoptosis of nasopharyngeal carcinoma cells.

LncRNA CASC19 Contributes to Radioresistance of Nasopharyngeal Carcinoma by Promoting Autophagy via AMPK-mTOR Pathway.

Nasopharyngeal carcinoma (NPC) is one of the most frequent head and neck malignant tumors and is majorly treated by radiotherapy. However, radiation resistance remains a serious obstacle to the successful treatment of NPC. The aim of this study was to discover the underlying mechanism of radioresistance and to elucidate novel genes that may play important roles in the regulation of NPC radiosensitivity. By using RNA-seq analysis of NPC cell line CNE2 and its radioresistant cell line CNE2R, lncRNA CASC19 was screened out as a candidate radioresistance marker. Both in vitro and in vivo data demonstrated that a high expression level of CASC19 was positively correlated with the radioresistance of NPC, and the radiosensitivity of NPC cells was considerably enhanced by knockdown of CASC19. The incidence of autophagy was enhanced in CNE2R in comparison with CNE2 and another NPC cell line HONE1, and silencing autophagy with LC3 siRNA (siLC3) sensitized NPC cells to irradiation. Furthermore, CASC19 siRNA (siCASC19) suppressed cellular autophagy by inhibiting the AMPK/mTOR pathway and promoted apoptosis through the PARP1 pathway. Our results revealed for the first time that lncRNA CASC19 contributed to the radioresistance of NPC by regulating autophagy. In significance, CASC19 might be a potential molecular biomarker and a new therapeutic target in NPC.

TRIM24 siRNA induced cell apoptosis and reduced cell viability in human nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) is a common cancer occurring primarily in East Asia and Africa. The high rate of recurrence and metastasis of NPC continuously endangers the health of patients. The present study aimed to identify the underlying mechanisms involved in the progression of NPC and provide experimental basis to develop a novel and efficient agent against NPC. The present study measured the expression level of tripartite motif containing24 (TRIM24) in tumor tissues from NPC patients using reverse transcription quantitative polymerase chain reaction. Subsequently, Cell Counting kit‑8 and flow cytometry were used to detect the cell proliferation and apoptosis of NPC cell lines HONE1 and CNE1 cells where the TRIM24 gene was knocked‑down with small interfering RNA (siRNA). Further, caspase kits and western blot analysis were used to detect the expression of apoptosis and angiogenesis‑associated proteins. The present study detected a higher expression level of TRIM24 in tumor tissues and NPC cell lines and lower cell viability and higher apoptotic rate were observed when TRIM24 was silenced. Meanwhile, upregulated caspase‑3 and caspase‑9 indicated induced cell apoptosis in HONE1 and CNE1 cells following the treatment with TRIM24 siRNA. Additionally, the downregulated expression level of vascular endothelial growth factor (VEGF) and VEGF receptor 2 suggested inhibited angiogenesis of NPC cells. Additionally, the reduced levels of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) indicated a blocked JAK2/STAT3 signaling pathway. However, there was no direct evidence that inactivation of the JAK2/STAT3 signaling pathway was involved in regulation of siTRIM24, these results suggested that TRIM24 has an important role in the growth of NPC. Additionally, silenced TRIM24 may lead to inhibited cell proliferation and induced cell apoptosis in NPC cells. The limitation of this study was that HONE1, CNE1 and CNE2 cells may have been contaminated with other cells. Further experiments with validated NPC cells may be needed.

Pan-CDK inhibition augments cisplatin lethality in nasopharyngeal carcinoma cell lines and xenograft models

In addition to their canonical roles in regulating cell cycle transition and transcription, cyclin-dependent kinases (CDKs) have been shown to coordinate DNA damage response pathways, suggesting a rational pairing of CDK inhibitors with genotoxic chemotherapeutic agents in the treatment of human malignancies. Here, we report that roniciclib (BAY1000394), a potent pan-CDK inhibitor, displays promising anti-neoplastic activity as a single agent and potentiates cisplatin lethality in preclinical nasopharyngeal carcinoma (NPC) models. Proliferation of the NPC cell lines HONE-1, CNE-2, C666-1, and HK-1 was effectively curbed by roniciclib treatment, with IC50 values between 11 and 38 nmol/L. These anticancer effects were mediated by pleiotropic mechanisms consistent with successful blockade of cell cycle CDKs 1, 2, 3, and 4 and transcriptional CDKs 7 and 9, ultimately resulting in arrest at G1/S and G2/M, downregulation of the transcriptional apparatus, and repression of anti-apoptotic proteins. Considerably enhanced tumor cell apoptosis was achieved following combined treatment with 10 nmol/L roniciclib and 2.0 μmol/L cisplatin; this combination therapy achieved a response over 250% greater than either drug alone. Although roniciclib chemosensitized NPC cells to cisplatin, it did not sensitize untransformed (NP69) cells. The administration of 0.5 mg/kg roniciclib to BALB/c xenograft mice was well tolerated and effectively restrained tumor growth comparable to treatment with 6 mg/kg cisplatin, whereas combining these two agents produced far greater tumor suppression than either of the monotherapies. In summary, these data demonstrate that roniciclib has strong anti-NPC activity and synergizes with cisplatin chemotherapy at clinically relevant doses, thus justifying further evaluation of this combinatorial approach in clinical settings.

Cytochrome b5 reductase 2 suppresses tumor formation in nasopharyngeal carcinoma by attenuating angiogenesis.

BackgroundCytochrome b5 reductase 2 (CYB5R2) is a potential tumor suppressor that inhibits cell proliferation and motility in nasopharyngeal carcinoma (NPC). Inactivation of CYB5R2 is associated with lymph node metastasis in NPC. This study aimed to explore the mechanisms contributing to the anti-neoplastic effects of CYB5R2.MethodsPolymerase chain reaction (PCR) assays were used to analyze the transcription of 84 genes known to be involved in representative cancer pathways in the NPC cell line HONE1. NPC cell lines CNE2 and HONE1 were transiently transfected with CYB5R2, and data was validated by real-time PCR. A chick chorioallantoic membrane (CAM) embryo model was implanted with CYB5R2-expressing CNE2 and HONE1 cells to evaluate the effect of CYB5R2 on angiogenesis. An immunohistochemical assay of the CAM model was used to analyze the protein expression of vascular endothelial growth factor (VEGF).ResultsIn CYB5R2-transfected NPC cells, PCR assays revealed up-regulated mRNA levels of Fas cell surface death receptor (FAS), FBJ murine osteosarcoma viral oncogene homolog (FOS), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), integrin beta 3 (ITGB3), metastasis suppressor 1 (MTSS1), interferon beta 1 (IFNB1), and cyclin-dependent kinase inhibitor 2A (CDKN2A) and down-regulated levels of integrin beta 5 (ITGB5), insulin-like growth factor 1 (IGF1), TEK tyrosine kinase (TEK), transforming growth factor beta receptor 1 (TGFBR1), and VEGF. The angiogenesis in the CAM model implanted with CYB5R2-transfected NPC cells was inhibited. Down-regulation of VEGF by CYB5R2 in NPC cells was confirmed by immunohistochemical staining in the CAM model.ConclusionCYB5R2 up-regulates the expression of genes that negatively modulate angiogenesis in NPC cells and down-regulates the expression of VEGF to reduce angiogenesis, thereby suppressing tumor formation.

Abstract 3098: The effects of a pan-cyclin dependent kinase (CDK) inhibitor and its combination with cisplatin in nasopharyngeal carcinoma (NPC)

Abstract Undifferentiated NPC is a unique epithelial malignancy endemic to South-east Asia and North Africa. Cell cycle dysregulation, mediated by mechanisms such as over-expression of cyclin D1 and down-regulation of p16INK4A is frequently found in NPC. Our previous work suggest that NPC cells are sensitive to the effects of cell cycle inhibition. BAY1000394 (BAY) is a potent pan-CDK inhibitor exhibiting broad anti-proliferation activity across a number of different cancer types. In this study, the anti-tumor effects of BAY alone and in combination with cisplatin on NPC cell lines were examined in vitro (MTS assay) and in a xenograft model. Cell cycle effects and apoptosis were examined via flowcytometry. Protein levels of relevant cell cycle regulators and mediators of apoptosis were assessed via Western Blot. Time-dependent inhibition of NPC cell lines HONE-1 and HK-1 by BAY was evaluated and demonstrated that growth inhibition of 50% of the cell population occurred by 48hrs of treatment. Mean IC50 of 30nM was seen. BAY inhibits phosphorylation of cellular CDK target proteins such as retinoblastoma (Ser807/811) (Rb), nucleophosmin (Thr199) (NPM) and RNA polymerase II (Ser2) (p-RNA POL II). Dephosphorylation of RNA POL II inhibits transcription of gene products resulting in rapid decline of MCL-1. Direct caspase-3 activation was observed with the concomitant appearance of active caspase-3; inducing PARP cleavage and inhibition of survivin. BAY was able to induce cell cycle arrest at multiple checkpoints thus enhancing apoptosis. Annexin V and PI staining after 96hrs of BAY exposure showed apoptosis of &amp;gt;80% of BAY treated cell. In vivo dosing of BAY1000394 at 0.5mg/kg and 1mg/kg showed significant growth inhibition as compared to control (p-value &amp;lt;0.05). Combination studies of BAY with cisplatin displayed synergistic cell kill. Cell cycle analysis of HONE-1 cells treated at 10nM and 20nM BAY with doses of cisplatin ranging from 0.5μM to 2μM showed marked increase in cell death as compared to control and NP69 epithelial cells. Protein expression of activated caspase-3, PARP cleavage and MCL-1 inhibition were observed in dual drug treatment groups. No change in expressions these proteins were seen in treated NP69 cells. In vivo assays of both drugs also demonstrated growth inhibition of tumor bearing mice at BAY 0.5mg/kg and 1.0mg/kg with cisplatin 6mg/kg with good tolerance. Tumor protein expression of p-RNA POL II, NPM and MCL-1 expression were suppressed, suggesting inhibition of CDK9/cyclin T1. Our data suggest that BAY inhibits NPC tumor cell proliferation in a time- and dose- dependent manner through inhibition of cell-cycle progression and induction of apoptosis. Combination studies with cisplatin suggest synergistic anti-tumor effect. This preliminary study strongly suggests that BAY and its combination with cisplatin has therapeutic potential in the treatment of NPC. Citation Format: Pei Li Lim, John SW Low, Gerhard Siemeister, Boon Cher Goh, Wen-son Hsieh. The effects of a pan-cyclin dependent kinase (CDK) inhibitor and its combination with cisplatin in nasopharyngeal carcinoma (NPC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3098. doi:10.1158/1538-7445.AM2015-3098

Pseudaboydins A and B: novel isobenzofuranone derivatives from marine fungus Pseudallescheria boydii associated with starfish Acanthaster planci.

Two novel isobenzofuranone derivatives, pseudaboydins A (1) and B (2), along with five known compounds, including (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-hydroxybenzofuran (3), (R)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-5-methoxybenzofuran (4), 3,3′-dihydroxy-5,5′-dimethyldiphenyl ether (5), 3-(3-methoxy-5-methylphenoxy)-5-methylphenol (6) and (−)-regiolone (7), were isolated from the culture broth of the marine fungus, Pseudallescheria boydii, associated with the starfish, Acanthaster planci. Their structures were elucidated primarily based on NMR and MS data. The absolute configurations of 1–4 were determined by CD spectroscopy and single-crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of 1–4 were evaluated. Pseudaboydin A (1) showed moderate cytotoxic activity against human nasopharyngeal carcinoma cell line HONE1, human nasopharyngeal carcinoma cell line SUNE1 and human glandular lung cancer cell line GLC82 with IC50 values of 37.1, 46.5 and 87.2 μM, respectively.

Epstein-Barr virus encoded latent membrane protein 1 regulates mTOR signaling pathway genes which predict poor prognosis of nasopharyngeal carcinoma

BackgroundThe oncoprotein Epstain-Barr Virus (EBV)-encoded latent membrane protein1 (LMP1) modulates the pathological effects of the NF-κB, AP-1 and JAK/STAT pathways in nasopharyngeal carcinoma (NPC).MethodsMicroarray analysis was performed on the NPC cell line HONE1 stably transfected with a LMP1-expression plasmid or an empty vector. Based on assigned pathways analyzed using the KEGG database, the mTOR signaling pathway was selected for verification by quantitative RT-PCR. Western blot, RNA interference and immunofluorescence were used to determine the relationship between LMP1 and mTOR signing pathway genes, and their clinical significance to NPC.ResultsOur studies revealed that overexpression of LMP1 upregulated the mTOR signaling pathway, possibly through phosphorylation of AKT/mTOR/P70S6K/4EBP1 in the NPC cell lines HONE1 and 6-10B. Knockdown of LMP1 reduced expression of p-mTOR and p-4EBP1 in EBV-positive NPC cell line C666-1. In addition, LMP1 expression closely correlated with expression of p-mTOR, p-P70S6K and p-4EBP1 in NPC tumors. Expression of p-P70S6K, p-4EBP1 and LMP1, but not p-mTOR, significantly correlated with overall survival of NPC patients. However, only LMP1 was an independent prognostic factor.ConclusionsThese results suggest that the mTOR signaling pathway is regulated by LMP1 expression in NPC. LMP1 and the genes in the mTOR pathway such as p-P70S6K and p-4EBP1 may be potential prognostic biomarkers.

Expression of bcl-2 correlates with poor prognosis and modulates migration of nasopharyngeal carcinoma cells

The role of bcl-2 expression, bcl-2 inhibitor HA14-1, and matrix metalloproteinase (MMP)-2 is still unclear in nasopharyngeal carcinoma (NPC). From 1996 to 2000, 145 patients with newly diagnosed NPC who were treated with high dose radiotherapy were enrolled. The relationship between bcl-2 expression, TNM stage, and disease-specific survival was analyzed. Furthermore, the NPC cell line HONE-1 was used to confirm the relationship between bcl-2 and cell metastasis. Among the 145 patients, 47 (32.4%) of them were bcl-2 positive. The expression of bcl-2 was significantly correlated with neck lymph node metastasis (p=0.006), and patients with negative bcl-2 expression had better disease-free survival (p=0.007). A Cox regression model revealed that only bcl-2 expression (p=0.023) and stage IV (p=0.043) were statistically significant in the prognosis of NPC. In vitro analysis also showed that treatment with the bcl-2 inhibitor HA14-1 exerted an inhibitory effect on migration and expression of MMP-2 in HONE-1 cells. Bcl-2 expression represents an important and easily assayed prognostic factor, and it may play an important role in lymph node metastasis. Inhibition of the migration mediated by MMP-2 may be a key feature for the prevention of cancer metastasis.

ApoG2, a novel inhibitor of antiapoptotic Bcl‐2 family proteins, induces apoptosis and suppresses tumor growth in nasopharyngeal carcinoma xenografts

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in South China. It has been reported that overexpression of antiapoptotic Bcl-2 family proteins in NPC has caused the lack of long-term efficacy of conventional therapies. Apogossypolone (ApoG2), a novel small-molecule inhibitor of antiapoptotic Bcl-2 family proteins, has been discovered as the optimized derivative of gossypol. In this study, we found that in NPC cells, ApoG2 totally blocked the antiapoptotic function of Bcl-2 family proteins without affecting the expression levels of these proteins. ApoG2 selectively inhibited proliferation of 3 NPC cell lines (C666-1, CNE-1 and CNE-2) that highly expressed the antiapoptotic Bcl-2 proteins. This inhibitory activity was associated with release of cytochrome c, activation of caspase-9 and caspase-3 and apoptosis of sensitive NPC cells. However, ApoG2 had no obvious inhibitory effect on NPC cell line HONE-1, which expressed antiapoptotic Bcl-2 and Bcl-xL at a low level. We further found that ApoG2 effectively suppressed tumor growth of NPC xenografts in nude mice and enhanced the antitumor effect of CDDP (cisplatin) on NPC cells in vitro and in vivo. Immunohistochemical results showed that the expression of CD31 decreased after ApoG2 treatment, which suggested inhibition of angiogenesis in NPC xenografts. Our findings strongly suggest that ApoG2 may serve as a novel inhibitor of Bcl-2 family proteins and, by targeting these proteins, may become a promising drug for the treatment of NPC.

Norepinephrine Up-regulates the Expression of Vascular Endothelial Growth Factor, Matrix Metalloproteinase (MMP)-2, and MMP-9 in Nasopharyngeal Carcinoma Tumor Cells

Recent studies using ovarian cancer cells have shown that the catecholamine hormones norepinephrine (norepi) and epinephrine (epi) may influence cancer progression by modulating the expression of matrix metalloproteinases (MMP) and vascular endothelial growth factor (VEGF). The purpose of this study is to determine if the stress hormone norepi can influence the expression of MMP-2, MMP-9, and VEGF in nasopharyngeal carcinoma (NPC) tumors by using three NPC tumor cell lines. The NPC cell lines HONE-1, HNE-1, and CNE-1 were treated with norepi. The effects of norepi on MMP-2, MMP-9, and VEGF synthesis were measured by ELISA; functional MMP activity was measured by the invasive potential of the cells using a membrane invasion culture system whereas functional activity of VEGF was analyzed using a human umbilical vein endothelial cell tube formation assay. Norepi treatment increased MMP-2, MMP-9, and VEGF levels in culture supernatants of HONE-1 cells, which could be inhibited by the beta-blocker propranolol. Norepi induced the invasiveness of all NPC cell lines in a dose-dependent manner, which was blocked by CMT-3, an MMP inhibitor, and propranolol. Norepi stimulated the release of functional angiogenic VEGF by HONE-1 cells as well. Finally, HONE-1 cells were shown to express beta-adrenergic receptors as did seven of seven NPC biopsies examined. The data suggest that catecholamine hormones produced by the sympathetic-adrenal medullary axis may affect NPC tumor progression, in part, through modulation of key angiogenic cytokines.

A functional investigation of tumor suppressor gene activities in a nasopharyngeal carcinoma cell line HONE1 using a monochromosome transfer approach.

Monochromosome transfers of selected chromosomes into a nasopharyngeal carcinoma (NPC) cell line were performed to determine if tumor suppressing activity for NPC mapped to chromosomes 9, 11, and 17. Current information from cytogenetic and molecular allelotyping studies indicate that these chromosomes may harbor potential tumor suppressor genes vital to NPC. The present results show the importance of CDKN2A on chromosome 9 in NPC development. There was no functional suppression of tumor development in nude mice with microcell hybrids harboring the newly transferred chromosome 9 containing an interstitial deletion at 9p21, whereas transfection of CDKN2A into the NPC HONE1 cells resulted in obvious growth suppression. Whereas intact chromosome 17 transfers into HONE1 cells showed no functional suppression of tumor formation, chromosome 11 was able to do so. Molecular analysis of chromosome 11 tumor segregants indicated that at least two tumor suppressive regions mapping to 11q13 and 11q22-23 may be critical for the development of NPC.