NAD(P)H:quinone Oxidoreductase 1 Is Involved in AZ-1-induced Apoptotic Effects in Nasopharyngeal Carcinoma TW01 Cells.

BACKGROUND/AIM: Current NPC treatment methods have improved the 5-year survival rates of patients; however, some patients do not benefit from the treatments. Therefore, the existing treatment methods or new drugs must be developed to improve the patient's prognosis. NAD (P)H:quinone oxidoreductase 1 (NQO1), an electron reductase highly expressed in various cancers, can convert aziridinyl-substituted quinone-derived compound into an alkylating agent, resulting in cell apoptosis. Therefore, a di-aziridinyl-substituted quinone-derived compound, AZ-1, was designed previously. The present study investigated whether AZ-1 has anticancer activities in NPC cells and explored the underlying mechanism. MATERIALS AND METHODS: NPC-TW01 cells were used in the study, and 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide, colony formation, terminal deoxynucleotidyl transferase dUTP nick end labeling, and immunoblotting assays were performed to assess the cell viability, cell survival, DNA fragmentation, and protein expression, respectively. RESULTS: The results show that AZ-1 significantly inhibited the viability and survival of NPC-TW01 cells. AZ-1 also induced the expression of cleaved PARP, cleaved caspase-8, cleaved caspase-9, and cleaved caspase-3, and triggered DNA fragmentation in NPC-TW01 cells. In addition, AZ-1 induced γH2AX expression, a DNA damage marker, in NPC-TW01 cells. Treatment with dicoumarol, an NQO1 activity inhibitor, not only reversed AZ-1-induced cell viability inhibition but also decreased AZ-1-induced expression of γH2AX, cleaved caspase-8, cleaved caspase-9, and cleaved caspase-3. CONCLUSION: NQO1 reverses AZ-1-triggered cell viability inhibition, DNA damage, and apoptosis. The findings of this study may provide a basis for the possible clinical application of AZ-1 in the treatment of NPC to improve the prognosis of patients with NPC.

Qing Yan Li Ge Tang Induces Apoptosis in Human OEC-M1 Oral Cancer Cells.

Background: Since most patients with oral cancer do not benefit from current treatments, new therapeutic strategies or drugs must be developed to improve patient prognosis. Qing Yan Li Ge Tang (QYLGT), a Chinese herbal medicine, is known for its anticancer activity. This study aimed to investigate whether QYLGT has anticancer effects on human OEC-M1 oral cancer cells. Methods: To evaluate whether QYLGT affects viability, morphology, and colony formation ability of the OEC-M1 cells, the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, morphology study, and colony formation assay were performed, respectively. Each assay was carried out in triplicate, and the whole set of experiments was performed three times independently. To investigate whether QYLGT induces apoptotic effects in OEC-M1 cells, the enzyme-linked immunosorbent (ELISA) was carried out to quantify cytokeratin 18 fragment (an apoptosis marker). Each assay was carried out in triplicate, and the whole set of experiments was performed three times independently. The immunoblotting assay was performed to detect the protein expression after QYLGT treatment. The whole set of experiments was performed two times independently. Results: The results from the MTT and colony formation assays indicate that QYLGT inhibited the cell viability and clonogenic growth capacity of OEC-M1 cells. The morphology study shows that QYLGT increased plasma membrane blebbing in OEC-M1 clles. The results of ELISA and an immunoblotting assay show that QYLGT increased cytokeratin 18 fragment release and poly ADP-ribose polymerase cleavage (another apoptosis marker) in OEC-M1 cells. In addition, the results from immunoblotting assay show that QYLGT also activated apoptotic executor proteins, including caspase-8, caspase-9, and caspase-3, and the results of ELISA indicate that treatment with the pan-caspase inhibitor, Z-VAD-FMK, inhibited QYLGT-induced cytokeratin 18 fragment release. These results indicate that QYLGT inhibited cell viability in OEC-M1 cells and induced OEC-M1 apoptosis through caspase activation. Additionally, QYLGT-activated c-Jun N-terminal kinase, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and nuclear factor-kappa B (NF-κB), and the related inhibitors, including SP600125, PD184352, SB202190, and Bay11-7082, were used to confirm which signaling was involved in QYLGT-induced apoptosis. Moreover, only Bay11-7082, the NF-κB inhibitor, could suppress QYLGT-induced the release of cytokeratin 18 fragments from OEC-M1 cells. Conclusions: QYLGT induced apoptosis in OEC-M1 cells via the NF-κB pathway.

Fucoidan Enhances Cisplatin-induced Effects on SCC-25 Human Oral Cancer Cells by Inhibiting the PI3K/AKT Pathway.

BACKGROUND/AIM: Cisplatin is a drug for treating oral cancer. However, several previous studies indicate that oral cancer cells can develop resistance to cisplatin, which may result in a poor prognosis for patients with oral cancer. Fucoidan, a natural health product extracted from brown seaweed, has anticancer abilities against various types of cancer cell. This study evaluated whether fucoidan can enhance the sensitivity of oral cancer cells to cisplatin and explored the underlying mechanism. MATERIALS AND METHODS: SCC-25 cells were used in the present study and treated with 0.3125 mg/ml fucoidan, 12.5 µg/ml cisplatin, or 0.3125 mg/ml fucoidan plus 12.5 µg/ml cisplatin for 48 h, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, enzyme-linked immunosorbent, and immunoblotting assays were performed to evaluate cell survival, cytokeratin-18 fragment release, and expression of markers of apoptosis and autophagy, respectively. RESULTS: Cotreatment with fucoidan enhanced cisplatin-induced reduction of SCC-25 cell survival compared to cisplatin alone. In addition, cotreatment also increased the expression of apoptosis markers, including activated caspase-8, activated caspase-9, activated caspase-3, and cleaved poly(ADP-ribose) polymerase (PARP), but did not increase the expression of the two autophagy markers studied, beclin and autophagy-related 12-autophagy-related 5 conjugate. Fucoidan significantly inhibited cisplatin-induced AKT serine/threonine kinase 1 activation, which promoted PARP cleavage, caspase-3 activation, and cytokeratin-18 fragment expression in SCC-25 cells. CONCLUSION: Fucoidan promoted cisplatin-induced effects by inhibiting phosphatidylinositol 4,5 bisphosphate 3 kinase/AKT serine/threonine kinase 1 activation induced by cisplatin. The results of this study may provide a basis for the possible application of the combination of fucoidan and cisplatin in the clinical treatment of oral cancer in the future to improve the prognosis of patients with oral cancer.

Serum Starvation Induces Matrix Metalloproteinase 9 Expression in Nasopharyngeal Carcinoma Cells Through the ERK-AP1 Pathway In Vitro.

BACKGROUND/AIM: Although clinical medicine has significantly progressed in treating nasopharyngeal carcinoma (NPC) in recent years, many patients still have poor prognoses due to distant metastasis. It is still relatively unclear why NPC has a highly metastatic ability. Especially whether the tumor microenvironment affects the invasion and metastasis of NPC still needs to be cleared. In this study, serum starvation was used to simulate nutrient deficiency in the tumor microenvironment to explore whether nutrient deficiency affects the malignancy of NPC cells. MATERIALS AND METHODS: Semiquantitative reverse transcription-polymerase chain reaction, ELISA, immunoblotting assay, reporter gene assay, and Matrigel invasion assay were carried out. RESULTS: Under serum starvation, NPC cells could induce the mRNA expression and protein secretion of matrix metalloproteinase 9 (MMP9). The ERK-AP1 pathway was activated under serum starvation in NPC cells, resulting in the expression of MMP9. In contrast, treatment with an MMP9 inhibitor or an MMP9 siRNA inhibited serum starvation-induced invasion. CONCLUSION: Serum starvation could up-regulate MMP9 expression in NPC cells, contributing to NPC invasion. Therefore, serum starvation may promote malignancy of NPC cells but also support MMP9 as a potential therapeutic target to prevent NPC cell invasion and metastasis.

Sodium arsenite and dimethylarsenic acid induces apoptosis in OC3 oral cavity cancer cells.

Although arsenic is an environmental toxicant, arsenic trioxide (ATO) is used to treat acute promyelocytic leukemia (APL) with anticancer effects. Studies have demonstrated oral cancer is in the top 10 cancers in Taiwan. High rate of oral cancers is linked to various behaviors, such as excessive alcohol consumption and tobacco use. Similarly, betel chewing is a strong risk factor in oral cancer. In the present study, oral squamous carcinoma OC3 cells were investigated with the treatments of sodium arsenite (NaAsO2) and dimethylarsenic acid (DMA), respectively, to examine if arsenic compounds have anti­cancer efforts. It was found that 1 µM NaAsO2 and 1 mM DMA for 24 h induced rounded contours with membrane blebbing phenomena in OC3 cells, revealing cell apoptotic characteristics. In addition, NaAsO2 (10­100 µM) and DMA (1­100 mM) significantly decreased OC3 cell survival. In cell cycle regulation detected by flow cytometry, NaAsO2 and DMA significantly augmented percentage of subG1 and G2/M phases in OC3 cells, respectively. Annexin V/PI double staining assay was further used to confirm NaAsO2 and DMA did induce OC3 cell apoptosis. In mechanism investigation, western blotting assay was applied and the results showed that NaAsO2 and DMA significantly induced phosphorylation of JNK, ERK1/2 and p38 and then the cleavages of caspase­8, ­9, ­3 and poly ADP­ribose polymerase (PARP) in OC3 cells, dynamically. In conclusion, NaAsO2 and DMA activated MAPK pathways and then apoptotic pathways to induce OC3 oral cancer cell apoptosis.

Arsenic compounds induce apoptosis by activating the MAPK and caspase pathways in FaDu oral squamous carcinoma cells.

For a number of years, oral cancer has remained in the top ten most common types of cancer, with an incidence rate that is steadily increasing. In total, ~75% oral cancer cases are associated with lifestyle factors, including uncontrolled alcohol consumption, betel and tobacco chewing, and the excessive use of tobacco. Notably, betel chewing is highly associated with oral cancer in Southeast Asia. Arsenic is a key environmental toxicant; however, arsenic trioxide has been used as a medicine for the treatment of acute promyelocytic leukemia, highlighting its anticancer properties. The present study aimed to investigate the role of arsenic compounds in the treatment of cancer, using FaDu oral squamous carcinoma cells treated with sodium arsenite (NaAsO2) and dimethyl arsenic acid (DMA). The results demonstrated that FaDu cells exhibited membrane blebbing phenomena and high levels of apoptosis following treatment with 10 µM NaAsO2 and 1 mM DMA for 24 h. The results of cell viability assay demonstrated that the rate of FaDu cell survival was markedly reduced as the concentration of arsenic compounds increased from 10 to 100 µM NaAsO2, and 1 to 100 mM DMA. Moreover, flow cytometry was carried out to further examine the effects of arsenic compounds on FaDu cell cycle regulation; the results revealed that treatment with NaAsO2 and DMA led to a significant increase in the percentage of FaDu cells in the sub­G1 and G2/M phases of the cell cycle. An Annexin V/PI double staining assay was subsequently performed to verify the levels of FaDu cell apoptosis following treatment with arsenic compounds. Furthermore, the results of the western blot analyses revealed that the expression levels of caspase­8, ­9 and ­3, and poly ADP­ribose polymerase, as well the levels of phosphorylated JNK and ERK1/2 were increased following treatment with NaAsO2 and DMA in the FaDu cells. On the whole, the results of the present study revealed that treatment with NaAsO2 and DMA promoted the apoptosis of FaDu oral cancer cells, by activating MAPK pathways, as well as the extrinsic and intrinsic apoptotic pathways.

Cordycepin Induces Apoptosis through JNK-Mediated Caspase Activation in Human OEC-M1 Oral Cancer Cells.

Cordycepin, a bioactive compound extracted from Cordyceps sinensis, can induce apoptosis in human OEC-M1 oral cancer cells. However, the exact mechanism is still unclear. The present study aimed to investigate the underlying mechanism of cordycepin-induced apoptosis in OEC-M1 cells. Following treatment with cordycepin, apoptosis was examined and quantified using a DNA laddering assay and a cytokeratin 18 fragment enzyme-linked immunosorbent assay, respectively. Expressions of mitogen-activated protein kinases (MAPKs) and apoptosis-related proteins were detected by the western blot analysis. Our results show that a pan-caspase inhibitor, Z-VAD-FMK, could significantly inhibit cordycepin-induced apoptosis in OEC-M1 cells. In addition, treatment with cordycepin not only activated caspase-8, caspase-9, and caspase-3 but also induced Bid and poly ADP-ribose polymerase cleavages. Furthermore, cordycepin also induced the activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase, and p38 MAPKs. Among MAPKs, activation of JNK solely contributed to cordycepin-induced apoptosis with the activation of caspase-8, caspase-9, and caspase-3 and cleavage of PARP. Taken together, the present study demonstrated that cordycepin activated JNK and caspase pathways to induce apoptosis in OEC-M1 cells.

Qing Yan Li Ge Tang, a Chinese Herbal Formula, Induces Autophagic Cell Death through the PI3K/Akt/mTOR Pathway in Nasopharyngeal Carcinoma Cells In Vitro.

Since a portion of patients with nasopharyngeal carcinoma (NPC) do not benefit much from current standard treatments, it is still needed to discover new therapeutic drugs to improve the prognosis of the patients. Considering that Chinese traditional medicine plays a role in inhibiting tumor progression, in this study, we aimed to investigate whether a Chinese herbal formula, Qing Yan Li Ge Tang (QYLGT), has the anticancer activity in NPC cells and explore the underlying mechanism as well. MTT assay, colony formation assay, immunoblotting assay, and DNA laddering assay were performed to assess cell viability, cell colony formation, protein expression, and DNA fragmentation, respectively. Results show that QYLGT was able to inhibit the cell viability and decrease colony formation ability in NPC cells. QYLGT could also increase the formation of intracellular vacuoles and induce the autophagy-related protein expressions, including Atg3, Atg6, and Atg12-Atg5 conjugate in NPC cells. Treatment with an autophagy inhibitor, 3-methyladenine, could significantly recover QYLGT-inhibited cell viability of NPC cells. In addition, QYLGT did not significantly induce apoptosis in NPC cells. We also found that QYLGT had the ability to activate phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of the rapamycin (mTOR) pathway. Treatment with PI3K inhibitors, LY294002 and wortmannin, or mTOR inhibitors, rapamycin and Torin 1, could not only recover QYLGT-inhibited cell viability of NPC cells but also inhibit Atg3 expression. Taken together, our results demonstrated that QYLGT could induce autophagic cell death in NPC cells through the PI3K/Akt/mTOR pathway.

Role of JNK activation in paclitaxel-induced apoptosis in human head and neck squamous cell carcinoma.

It has been reported that paclitaxel activates cell cycle arrest and increases caspase protein expression to induce apoptosis in head and neck squamous cell carcinoma (HNSCC) cell lines. However, the potential signaling pathway regulating this apoptotic phenomenon remains unclear. The present study used OEC-M1 cells to investigate the underlying molecular mechanism of paclitaxel-induced apoptosis. Following treatment with paclitaxel, cell viability was assessed via the MTT assay. Necrosis, apoptosis, cell cycle and mitochondrial membrane potential (∆Ψm) were analyzed via flow cytometric analyses, respectively. Western blot analysis was performed to detect the expression levels of proteins associated with the MAPK and caspase signaling pathways. The results demonstrated that low-dose paclitaxel (50 nM) induced apoptosis but not necrosis in HNSCC cells. In addition, paclitaxel activated the c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase or p38 mitogen-activated protein kinase. The paclitaxel-activated JNK contributed to paclitaxel-induced apoptosis, activation of caspase-3, -6, -7, -8 and -9, and reduction of ∆Ψm. In addition, caspase-8 and -9 inhibitors, respectively, significantly decreased paclitaxel-induced apoptosis. Notably, Bid was truncated following treatment with paclitaxel. Taken together, the results of the present study suggest that paclitaxel-activated JNK is required for caspase activation and loss of ∆Ψm, which results in apoptosis of HNSCC cells. These results may provide mechanistic basis for designing more effective paclitaxel-combining regimens to treat HNSCC.

EBV Rta-induced IL-6 Promotes Migration of Bystander Tumor Cells Through IL-6R/JAK/STAT3 Pathway In Vitro.

BACKGROUND/AIM: Rta, a transactivator of Epstein-Barr virus, is associated with progression of nasopharyngel carcinoma (NPC); however, its mechanism of contribution to the pathogenesis of NPC remains unclear. Interleukin-6 (IL-6), a tumor promoter, is detected in NPC. This in vitro study examined whether and how Rta promotes NPC progression by up-regulating IL-6. MATERIALS AND METHODS: Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time PCR, ELISA, immunoblotting assays, reporter gene assays, and transwell migration assays were performed. RESULTS: In NPC cells, Rta up-regulated IL-6 expression at the mRNA and protein levels, and the Rta's C-terminus was essential for promoter activation and expression of IL-6. The induction of IL-6 by Rta also required activation of extracellular signal-regulated kinase 1/2 and activator protein-1. Furthermore, IL-6 secreted from Rta-expressing NPC cells promoted migration of Rta-negative NPC cells by activating IL-6 receptor/Janus kinase/signal transducer and activator of transcription 3 pathway. CONCLUSION: Rta contributes to progression of NPC cells through induction of IL-6 in vitro.

Epstein-Barr virus Rta promotes invasion of bystander tumor cells through paracrine of matrix metalloproteinase 9.

Clinical studies suggest a positive association between malignant progression of nasopharyngeal carcinoma (NPC) and Rta, a transcription factor of Epstein-Barr virus (EBV). However, Rta induces cellular senescence in vitro. To provide an underlying mechanism integrating these clues, we adapted a concept of senescence-associated secretory phenotype (SASP), based on which senescent cells facilitate tumor progression through paracrine. First, Rta-expressing NPC cells themselves show reduced invasiveness but promote invasion of Rta-negative tumor cells through secreted factors. Secretion of matrix metalloproteinase 9 (MMP9), an SASP protein, is increased by Rta, which requires the C-terminus of Rta and Rta-induced activation of E2F. Furthermore, the Rta-induced, paracrine-mediated pro-invasive effect is blocked upon knockdown of MMP9 expression or treatment with an MMP9 inhibitor. This study not only indicates that Rta can contribute to NPC progression through paracrine but also supports that MMP9 is a potential therapeutic target to prevent NPC metastasis.

Exogenous nerve growth factor protects the hypoglossal nerve against crush injury.

Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase (MAPK) pathway, but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear. Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury, but there has been little research focusing on the hypoglossal nerve injury and repair. In this study, we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days. p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury; exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus. Under transmission electron microscopy, we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury. Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury.

Strategies of oncogenic microbes to deal with WW domain-containing oxidoreductase.

WW domain-containing oxidoreductase (WWOX) is a well-documented tumor suppressor protein that controls growth, survival, and metastasis of malignant cells. To counteract WWOX's suppressive effects, cancer cells have developed many strategies either to downregulate WWOX expression or to functionally inactivate WWOX. Relatively unknown is, in the context of those cancers associated with certain viruses or bacteria, how the oncogenic pathogens deal with WWOX. Here we review recent studies showing different strategies utilized by three cancer-associated pathogens. Helicobactor pylori reduces WWOX expression through promoter hypermethylation, an epigenetic mechanism also occurring in many other cancer cells. WWOX has a potential to block canonical NF-κB activation and tumorigenesis induced by Tax, an oncoprotein of human T-cell leukemia virus. Tax successfully overcomes the blockage by inhibiting WWOX expression through activation of the non-canonical NF-κB pathway. On the other hand, latent membrane protein 2A of Epstein-Barr virus physically interacts with WWOX and redirects its function to trigger a signaling pathway that upregulates matrix metalloproteinase 9 and cancer cell invasion. These reports may be just "the tip of the iceberg" regarding multiple interactions between WWOX and oncogenic microbes. Further studies in this direction should expand our understanding of infection-driven oncogenesis.

WW domain-containing oxidoreductase is involved in upregulation of matrix metalloproteinase 9 by Epstein-Barr virus latent membrane protein 2A.

WW domain-containing oxidoreductase (WOX1) participates in tumor suppression and many other biologic functions, but its molecular and functional interactions with viral proteins remain largely unknown. This study reveals that WOX1 is physically associated with latent membrane protein 2A (LMP2A), an oncoprotein of Epstein-Barr virus. The molecular interaction involves the tyrosine residue 33 of WOX1 and the proline-rich motifs of LMP2A. Interestingly, endogenous WOX1 is required for some LMP2A-triggered, cancer-promoting effects, including activation of extracellular signal-regulated kinase-1/2, upregulation of matrix metalloproteinase 9 (MMP9) and promotion of cell invasion. Upon knockdown of endogenous WOX1, LMP2A-triggered MMP9 induction is restored by exogenous wild-type WOX1, but not by a WOX1 mutant defective in LMP2A binding. These results indicate that, through interaction with LMP2A, WOX1 is involved in MMP9 induction, suggesting a novel role of WOX1 in Epstein-Barr virus-associated cancer progression.

Epstein-Barr virus Zta upregulates matrix metalloproteinases 3 and 9 that synergistically promote cell invasion in vitro.

Zta is a lytic transactivator of Epstein-Barr virus (EBV) and has been shown to promote migration and invasion of epithelial cells. Although previous studies indicate that Zta induces expression of matrix metalloproteinase (MMP) 9 and MMP1, direct evidence linking the MMPs to Zta-induced cell migration and invasion is still lacking. Here we performed a series of in vitro studies to re-examine the expression profile and biologic functions of Zta-induced MMPs in epithelial cells derived from nasopharyngeal carcinoma. We found that, in addition to MMP9, MMP3 was a new target gene upregulated by Zta. Ectopic Zta expression in EBV-negative cells increased both mRNA and protein production of MMP3. Endogenous Zta also contributed to induction of MMP3 expression, migration and invasion of EBV-infected cells. Zta activated the MMP3 promoter through three AP-1 elements, and its DNA-binding domain was required for the promoter binding and MMP3 induction. We further tested the effects of MMP3 and MMP9 on cell motility and invasiveness in vitro. Zta-promoted cell migration required MMP3 but not MMP9. On the other hand, both MMP3 and MMP9 were essential for Zta-induced cell invasion, and co-expression of the two MMPs synergistically increased cell invasiveness. Therefore, this study provides integrated evidence demonstrating that, at least in the in vitro cell models, Zta drives cell migration and invasion through MMPs.

[Effects of propofol on expression of hippocampal survivin and Caspase-3 in newborn rats].

OBJECTIVE: Intravenous anesthetics, such as propofol, are widely used in general anesthesia. Neurodegeneration and neurocognitive impairment after exposure to propofol in neonatal rats have raised concerns regarding the safety of pediatric anesthesia. We examined the effects of neonatal propofol exposure on brain cell viability, as well as expression of hippocampal survivin and Caspase-3 mRNA and protein. METHODS: One hundred male Sprague-Dawley rats aged 7 d that were weighed 10-15 g were randomly divided into 4 groups (n = 25 each group). Group A: the rats were injected with no drugs. Group B: the rats were intraperitoneally injected with 50 mg/kg propofol. Group C: the rats were first intraperitoneally injected with 50 mg/kg propofol and another 50 mg/kg propofol was used when the dynamic response of rats appeared again. Group D: the rats were first intraperitoneally injected with 50 mg/kg propofol and another 50 mg/kg propofol was used three times once the dynamic response of rats appeared. To study the effects of propofol exposure on respiratory and metabolic function, arterial blood was aspirated from the left ventricle of neonatal rats 2 h after discontinuation of propofol. pH, PaO(2), PaCO(2), HCO(3)(-), BE and SaO(2) were detected by blood gas analyzer. Moreover, to examine the effects of propofol exposure on short-term cellular viability, the ultrastructure of neurons was observed by transmission electron microscope and Fluoro-Jade B (FJB) staining was performed to examine neuronal degeneration in hippocampal CA1 region of neonatal rats. Survivin and Caspase-3 mRNA and protein expression in hippocampus were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting 2 h after discontinuation of propofol. RESULTS: The time of anesthesia maintaince in newborn rats was the longest in Group D and the time of anesthesia maintaince in Group C was longer than that in Group B. Two hours after discontinuation of propofol, pH, PaO(2), PaCO(2), HCO(3)(-), BE and SaO(2) of arterial blood in rats were not significantly different among groups A, B, C and D (P > 0.05). The structure of hippocampal neurons was normal in Group A and Group B while 100 mg/kg propofol resulted in nuclear blebbing and 200 mg/kg propofol led to nuclear fragmentation, chromatin condensation and apoptotic bodies. Cellular degeneration, as measured by Fluoro-Jade B staining, significantly increased in hippocampal CA1 region in the anesthesia groups compared with littermates in the no anesthesia group. FJB-positive stained degenerative neurons in groups B, C and D were (2.5 ± 1.3), (7.1 ± 2.3) and (9.4 ± 2.6), which were different from that in Group A (0.6 ± 0.3) (P < 0.05). Moreover, the number of FJB-positive neurons was the highest in Group D, that in Group C was more than that in Group B. At the same time point, apoptosis was measured by expression of Caspase-3 and Survivin mRNA and protein in hippocampus of rats. Caspase-3 mRNA in groups A, B and C was (0.78 ± 0.12), (0.84 ± 0.17) and (0.89 ± 0.19), while Caspase-3 protein in groups A, B and C was (0.22 ± 0.05), (0.26 ± 0.07) and (0.21 ± 0.06). Survivin mRNA in groups A, B and C was (0.56 ± 0.12), (0.58 ± 0.15) and (0.53 ± 0.16), while Survivin protein in these 3 groups was (0.24 ± 0.07), (0.21 ± 0.05) and (0.23 ± 0.06). Compared with that in Group A, Caspase-3 and Survivin mRNA and protein were not significantly different among Group B and Group C (P > 0.05). However, Caspase-3 mRNA and protein in Group D were (1.21 ± 0.14) and (0.42 ± 0.12), which were higher than that in the other 3 groups (P < 0.05). Survivin mRNA and protein in Group D were lower than that in the other 3 groups (P < 0.05). CONCLUSIONS: A high dose of propofol exposure may destroy the structure of neurons, induce neurodegeneration, increase Caspase-3 activity and inhibit survivin expression in hippocampus of newborn rats in vivo.

Epstein-Barr virus latent membrane protein 2A promotes invasion of nasopharyngeal carcinoma cells through ERK/Fra-1-mediated induction of matrix metalloproteinase 9.

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is highly metastatic, and this malignant feature may be promoted by an EBV oncoprotein, latent membrane protein 2A (LMP2A). Acting as a signal regulator, LMP2A can enhance invasiveness and motility of epithelial cells. Downstream from the LMP2A-triggered signaling events, it is largely unknown what key effector proteins are induced and essentially promote cell invasion. In the present study, we found that in NPC cells, LMP2A upregulated matrix metalloproteinase 9 (MMP9), a metastasis-associated protease. LMP2A increased MMP9 expression at both the mRNA and protein levels. It also activated the MMP9 promoter, in which two AP-1 elements were required for the promoter activation. Among AP-1 transcription factors, Fra-1 was induced by LMP2A and is essential for LMP2A-triggered MMP9 expression. Induction of Fra-1 was dependent on the LMP2A-activated ERK1/2 pathway, and induction of the ERK1/2-Fra-1-MMP9 axis required PY motifs in the amino-terminal domain of LMP2A. Notably, LMP2A-promoted invasion of NPC cells was blocked when MMP9 expression, Fra-1 induction, or ERK1/2 activation was inhibited. In addition, we found an association of LMP2A with MMP9 expression in NPC tumor biopsy specimens, where Fra-1 was a major mediation factor. This study reveals an underlying mechanism of LMP2A-induced cell invasion, from signal transduction to upregulation of a critical protease. Considering that MMP9 can also be upregulated by another EBV oncoprotein, LMP1, this protease may be a pivotal effector at which the EBV-induced, invasion-promoting mechanisms converge, serving as an attractive therapeutic target for NPC treatment.