[show abstract][hide abstract] ABSTRACT: Phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin inhibitor (mTOR) pathway is often constitutively activated in human tumor cells and thus has been considered as a promising drug target. To ascertain a therapeutical approach of nasopharyngeal carcinoma (NPC), we hypothesized NVP-BEZ235, a novel and potent imidazo[4,5-c] quinolone derivative, that dually inhibits both PI3K and mTOR kinases activities, had antitumor activity in NPC. Expectedly, we found that NVP-BEZ235 selectively inhibited proliferation of NPC cells rather than normal nasopharyngeal cells using MTT assay. In NPC cell lines, with the extended exposure, NVP-BEZ235 selectively inhibited proliferation of NPC cells harboring PIK3CA mutation, compared to cells with wild-type PIK3CA. Furthermore, exposure of NPC cells to NVP-BEZ235 resulted in G1 growth arrest by Propidium iodide uptake assay, reduction of cyclin D1and CDK4, and increased levels of P27 and P21 by Western blotting, but negligible apoptosis. Moreover, we found that cisplatin (CDDP) activated PI3K/AKT and mTORC1 pathways and NVP-BEZ235 alleviated the activation by CDDP through dually targeting PI3K and mTOR kinases. Also, NVP-BEZ235 combining with CDDP synergistically inhibited proliferation and induced apoptosis in NPC cells. In CNE2 and HONE1 nude mice xenograft models, orally NVP-BEZ235 efficiently attenuated tumor growth with no obvious toxicity. In combination with NVP-BEZ235 and CDDP, there was dramatic synergy in shrinking tumor volumes and inducing apoptosis through increasing Noxa, Bax and decreasing Mcl-1, Bcl-2. Based on the above results, NVP-BEZ235, which has entered phase I/II clinical trials in patients with advanced solid tumors, has a potential as a monotherapy or in combination with CDDP for NPC treatment.
PLoS ONE 01/2013; 8(3):e59879. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: One of the best-characterized Nod-like receptor (NLR) family members is pyrin domain containing 3 (NLRP3). Intracellular NLRP3 is the most versatile innate immune receptor. On activation, NLRP3 assembles into a multiprotein complex, termed an inflammasome, which regulates the secretion and bioactivity of interleukin-1 family cytokines. NLRP3 has broad specificity for mediating an immune response to a wide range of microbial stimuli or danger signals. Therefore, we hypothesize that NLRP3 plays an essential role in the detection of bacterial pathogens and the initiation of inflammation within the dental pulp. Thus, the aim of this study was to evaluate the expression of NLRP3 in normal human dental pulp cells (HDPCs) and pulp tissues.
Pulp tissues were collected from freshly extracted human third molars, and HDPCs were prepared from the explants of normal dental pulp tissues. Reverse transcription-polymerase chain reaction and Western blotting were performed to detect the levels of NLRP3 mRNA and protein, respectively. In addition, immunohistochemical staining was used to determine the distribution of NLRP3 in pulp tissues.
Normal human dental pulp tissues displayed high levels of NLRP3 mRNA and protein. NLRP3 proteins were principally expressed in odontoblasts and some pulp vascular endothelial cells. Moreover, HDPCs also expressed NLRP3 but at a relatively low level in comparison with that of dental pulp tissues.
The expression of NLRP3 in HDPCs and pulp tissues suggests that NLRP3-mediated signaling pathways may play an important role in dental immune defense.
Journal of endodontics 12/2012; 38(12):1592-7. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: The purpose of this double-blind, randomised trial was to compare the clinical performance of a hybrid composite (Clearfil AP-X, Kuraray, Tokyo) and a nanocomposite (Filtek Z350, 3M ESPE, St. Paul, MN) over a period of 2 years in non-carious class V lesions using a modified US Public Health Service (USPHS) system. METHODS: Forty-six patients with at least one pair of equivalent non-carious cervical lesions under occlusion and a mean age of 44.1 years (range 27-66 years; median 45 years) were enrolled in this study. A total of 116 restorations (58 with each material) were placed according to manufacturer's instructions by two calibrated operators. The restorations were evaluated at baseline and at 6, 12 and 24 months after placement using the USPHS criteria for retention, colour match, marginal discolouration, marginal adaptation, anatomic form, surface texture and secondary caries. Statistical analysis was conducted using the Cochran and the McNemar tests at a significance level of 5 % (P < 0.05). RESULTS: No surface texture changes or secondary caries were detected in association with any restorations. The retention rates for Clearfil AP-X (100 %) and for Filtek Z350 (91.38 %) did not differ significantly (P > 0.05). Two Z350 restorations were completely lost after 2 years. No significant differences were observed in the colour match, marginal discolouration, marginal adaptation or anatomic form. CONCLUSIONS: There were no significant differences in the clinical performances between the materials. CLINICAL RELEVANCE: Both restorative materials exhibited acceptable clinical performance in class V non-carious lesions 2 years post-restoration.
[show abstract][hide abstract] ABSTRACT: Bone morphogenetic protein-2 (BMP-2) is a member of the transforming growth factor-β (TGF-β) superfamily, which has a broad range of activities that affect many different cell types. Previous research has suggested that BMP-2 induces the differentiation of human dental pulp cells (DPCs) into odontoblast-like cells. However, the mechanism by which BMP-2 induces odontoblastic differentiation has not yet been established. In the present study, we examined the involvement of the BMP/Smad pathway in mediating odontoblastic differentiation in DPCs.
Levels of phosphorylated and unphosphorylated Smad1/5 were quantified by Western blot analysis in response to BMP-2 and the BMP signaling inhibitor noggin. Some nuclear translocation of Smad1/5 was also observed by immunofluorescence staining in isolated DPCs treated with BMP-2. The effects of noggin on the BMP-2-induced odontoblastic differentiation of DPCs were determined by alkaline phosphatase activity assay, and the expression of odontoblastic markers was evaluated by reverse transcription polymerase chain reaction analysis and Western blotting.
We found that BMP-2 induced the phosphorylation and nuclear translocation of Smad 1/5. In addition, noggin significantly inhibited alkaline phosphatase activity and odontoblastic differentiation and reduced the formation of mineralized nodules in BMP-2-treated DPCs.
These findings suggest that Smad 1/5 is involved in BMP-2-induced odontoblastic differentiation in DPCs.
Journal of endodontics 01/2012; 38(1):66-71. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: The nucleotide-binding oligomerization domain (NOD) proteins belong to a distinct family of proteins that are implicated in the intracellular recognition of bacterial components. NOD2 appears to be a sensor of bacterial peptidoglycans because it recognizes a minimal motif present in all peptidoglycans. The interaction of NOD2 with downstream signaling molecules ultimately results in the activation of NF-kappaB and production of inflammatory mediators in innate immunity. As such, NOD2 may play an important role in the detection of bacterial pathogens and the initiation of inflammation within the dental pulp. This study was designed to evaluate the expression of NOD2 in normal human dental pulp cells (HDPCs) and human pulp tissues.
Human pulp tissue samples were collected from freshly extracted human wisdom teeth, and HDPCs were prepared from the explants of normal human dental pulp tissues. Nested reverse-transcription polymerase chain reaction (Nested RT-PCR) and Western blotting were performed to detect the expression of NOD2 messenger RNA and protein, respectively. Immunohistochemical staining was used to determine the distribution of NOD2 in the pulp tissues.
The NOD2 messenger RNA and protein were present in normal human dental pulp tissues, with most NOD2 protein expression being localized to odontoblasts and some pulp vascular endothelial cells. In contrast, HDPCs only showed a low level of NOD2 protein expression.
Our results suggest that NOD2 protein expressed in HDPCs and pulp tissues may play an important role in dental immune defense.
Journal of endodontics 07/2009; 35(6):838-42. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: Recombinant human bone morphogenetic protein-7 (BMP-7) has been shown to stimulate new reparative dentin formation in animal models. However, little is known about whether BMP-7 could promote the odontoblast-like differentiation and the formation of mineralized nodules in human dental pulp cells. Here, we reported that the infection with adenovirus-BMP-7 (Ad-BMP-7), a BMP-7-expressing adenoviral vector, induced the expression of BMP-7 in primarily cultured human dental pulp cells in the long term with little effect on their proliferation and viability. Importantly, BMP-7 expression significantly increased alkaline phosphatase activity and induced the dentin sialophosphoprotein expression in a dose- and time-dependent manner, suggesting that BMP-7 promoted the odontoblast differentiation. Furthermore, BMP-7 expression stimulated the formation of many mineralized dentin-like calcified nodules. Our data suggest that Ad-BMP-7-mediated BMP-7 expression can promote the differentiation of human pulp cells into odontoblast-like cells and mineralization in vitro, which may provide insight for the design of new gene therapy for the pulp capping in the clinic.
Journal of Endodontics 09/2007; 33(8):930-5. · 2.93 Impact Factor