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.

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.

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.

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.

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.

Bonding of dental porcelain to non-cast titanium with different surface treatments.

This study investigated the bonding of dental porcelain to non-cast Ti surface with different treatments. Mechanically ground non-cast Ti strips, simulating surface conditions produced by CAD/CAM, were Al(2)O(3)-sandblasted, then subjected to different surface treatments, including immersion in HNO(3)-containing acid, NaOH-containing alkaline, and NaOH-containing alkaline then HNO(3)-containing acid. Ti-porcelain specimens preparations and their bend strength measurements were based on ISO 9693. Ti surface treatment changed not only surface roughness but also surface chemistry, leading to influence on bond strength. Bond strengths of all Ti-porcelain groups were higher than ISO 9693 minimum requirement. The sandblasted/acid-treated Ti surface showed the highest bond strength (34.60 MPa) with porcelain; no significant difference in bond strength (27.92-29.63 MPa) was found among other Tiporcelain groups. All Ti-porcelain specimens showed adhesive bond failure. Bonding between non-cast Ti and dental porcelain was strengthened by a simple and practical sandblasting/acid-etching treatment of the Ti surface prior to porcelain sintering.