NDRG1 attenuates epithelial-mesenchymal transition of nasopharyngeal cancer cells via blocking Smad2 signaling.

N-myc downstream-regulated gene 1 (NDRG1) has been implicated in tumorigenesis and metastasis in different cancers. However, its role in nasopharyngeal carcinoma remains unknown. We found that NDRG1 expression level was high in nasopharyngeal cancer 5-8F cells but low in 5-8F-LN cells with lymphatic metastasis potential. Knockdown of NDRG1 by shRNA promoted 5-8F cell proliferation, migration, and invasion in vitro and its tumorigenesis in vivo. Moreover, NDRG1 deficiency induced an epithelial-mesenchymal transition (EMT) of 5-8F cells as shown by an attenuation of E-cadherin and an induction of N-cadherin and vimentin expression. NDRG1 knockdown also enhanced Smad2 expression and phosphorylation. Smad2 signaling was attenuated in 5-8F cells but was significantly activated in 5-8F-LN cells. Knockdown of Smad2 restored E-cadherin but attenuated N-cadherin expression in NDRG1-deficient 5-8F cells, suggesting a reduction of EMT. Consistently, blockade of Smad2 in 5-8F-LN cells increased E-cadherin while diminishing N-cadherin and vimentin expression. These data indicate that Smad2 mediates the NDRG1 deficiency-induced EMT of 5-8F cells. In tumors derived from NDRG1-deficient 5-8F cells, E-cadherin expression was inhibited while vimentin and Smad2 were increased in a large number of cancer cells. Most importantly, NDRG1 expression was attenuated in human nasopharyngeal carcinoma tissues, resulted in a lower survival rate in patients. The NDRG1 was further decreased in the detached nasopharyngeal cancer cells, which was associated with a further reduced survival rate in patients with lymphatic metastasis. Taken together, these results demonstrated that NDRG1 prevents nasopharyngeal tumorigenesis and metastasis via inhibiting Smad2-mediated EMT of nasopharyngeal cells.

Adsorption behavior of heavy metals onto microplastics derived from conventional and biodegradable commercial plastic products.

This study extensively explored the adsorption behavior of heavy metals (Pb+2, Ni+2, Cu+2, Zn+2, and Cd+2) onto microplastics (MPs). The particle sizes of MPs ranged from 0.149 to 0.25 mm. The microplastics were generated from commercial products manufactured from both conventional (polyethylene (PE) bottle, polystyrene (PS) spoon, and polyethylene terephthalate (PET) egg carton) and biodegradable (polylactic acid (PLA) spoon, and polylactic acid (PLA) egg carton) plastics. The study also considered the influence of solution pH on the adsorption capacity of heavy metals. Regarding the adsorption potential for Cu+2, the ranking was as follows: PLA-egg (1408 µg·g-1) > PLA-spoon (735 µg·g-1) > PE-bottle (315 µg·g-1) > PET-egg (283 µg·g-1) > PS-spoon (237 µg·g-1). PLA MPs showed the highest adsorption capacity due to the lower thermal stability and higher presence of surface oxygen functional groups. Moreover, the adsorption capacities of the five metals onto PLA-spoon and PLA-egg decreased in the following order: Pb (1785 µg·g-1) > Zn (1267 µg·g-1) > Cd (748 µg·g-1) > Cu (735 µg·g-1) > Ni (722 µg·g-1), and Pb (1520 µg·g-1) > Ni (1412 µg·g-1) > Cu (1408 µg·g-1) > Zn (1118 µg·g-1) > Cd (423 µg·g-1), respectively. The SEM-EDS, FTIR and XPS results demonstrated that surface oxygen-containing functional groups play an important role during the adsorption process. This study extended its analysis to quantify the metal content of the post-adsorption MPs, revealing uneven adsorption of heavy metals onto the MPs. This implies that the diversity of commercial plastic products may result in significant variations in their ability to adsorb heavy metals, underscoring the importance of effectively managing discarded commercial plastic products.

Poly[aqua-[µ(3)-4-carb-oxy-2-(pyridin-4-yl)-1H-imidazole-5-carboxyl-ato-κN,O:N,O:N]nickel(II)].

The water-coordinated Ni(2+) cation in the title compound, [Ni(C(10)H(5)N(3)O(4))(H(2)O)](n), assumes an octa-hedral NiN(3)O(3) coord-ination mode and is N,O-chelated by two deprotonated 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarb-oxy-lic acid (HPyImDC(2-)) ligands, forming a layer structure extending in the bc plane. The chains are arranged along the b-axis direction, forming a layer structure extending in the bc plane. O-H⋯O hydrogen bonding between the layers results in the formation of a three-dimensional supra-molecular framework. The structure is isotypic with the Zn analogue [Li et al. (2009). Cryst. Growth Des.6, 3423-3431].

Stretch-inducible expression of connective tissue growth factor (CTGF) in human osteoblasts-like cells is mediated by PI3K-JNK pathway.

To explore the possible role for connective tissue growth factor (CTGF) during tooth movement, we evaluated CTGF gene and protein expression in MG-63 cells subjected to cyclic stretch. Cyclic stretch caused a time-dependent increase in CTGF mRNA and protein levels.Inhibition of p38 MAP kinase or ERK activation did not affect cyclic stretch-induced CTGF expression. Specific inhibitors of PI3K suppressed stretch -induced CTGF expression in a time-dependent manner. cyclic stretch activated JNK and ERK, but not p38 MAP kinase in osteoblast-like cells. PI3K inhibitors suppressed cyclic stretch-induced JNK, but not p38 MAP kinase activation. Finally, SP600125, a Specific Inhibitor of JNK, suppressed stretch -induced CTGF Expression. These results suggest that stretch-induced CTGF expression is mediated through the PI3K-JNK -dependent pathway, not by p38 MAP kinase and ERK pathways.

[The prevalence of fenestration and dehiscence of anterior teeth in adolescent patients with unilateral cleft lip and palate: a cone-beam CT study].

PURPOSE: To assess the prevalence of fenestration and dehiscence of anterior teeth in adolescent patients with unilateral cleft lip and palate(UCLP). METHODS: Twenty-five males and seventeen females with UCLP who visited The Second Xiangya Hospital from June 2014 to September 2017 were selected. Forty-two age- and sex- matched non-cleft skeletal III patients were enrolled as the control group. Cone-beam CT（CBCT） scans were evaluated to detect fenestration and dehiscence．The data were analyzed using SPSS 22.0 software package. RESULTS: The prevalence of dehiscence of anterior teeth was 50.88% on the cleft side，42.39% on the non-cleft side and 28.77% on the controls, respectively. Dehiscence of maxillary teeth was more common on cleft side than the controls (P<0.05), and dehiscence of maxillary lateral incisor was common on non-cleft side compared with the control (P<0.05). Maxillary central incisor on the cleft side showed a higher prevalence of dehiscence compared with the non-cleft side (P<0.05). Most of the dehiscence was detected on the buccal side. Fenestration of the teeth showed no significant difference among the cleft side, non-cleft side and the control (P>0.05). CONCLUSIONS: Adolescent patients with UCLP show a high prevalence of fenestration and dehiscence，which deserves to be taken into consideration during clinical treatment.

[Comparisons of five different resin-removal methods on enamel surface].

PURPOSE: To compare enamel surface state and operating time following debonding by using 5 different resin removal methods. METHODS: Forty healthy human premolars extracted for orthodontic purpose were selected and then divided into 5 groups randomly based on different resin-removal methods, 8 in each group. After regular bonding brackets and debonding, tungsten carbide bur (group A), tungsten carbide bur+silicon particles(group B), corundum bur(group C), corundum bur+silicon particles (group D) and silicon particles (group E) were used respectively to deal with the enamel surfaces. The operating time(T) of each group was recorded. The samples were observed under scanning electron microscope (SEM), and enamel damage index(EDI) was recorded. The scores of EDI were analysed using SPSS 20.0 software package . RESULTS: The order of EDI was group C>group D>group A >group B>group E, significant difference was found between 5 groups (P<0.05). The order of operating time was group E>group D>group B>group A>group C, significant difference was found between 5 groups (P<0.05). CONCLUSIONS: Using tungsten carbide bur followed by silicon particles to remove residual resin on enamel surface causes less damage to the enamel surface, and requires reasonable time.

[Impacts of Environmental Conditions on the Soaking Release of Nitrogen and Phosphorus from Cynodon dactylon (Linn.) Pers. in the Water-level Fluctuation Zone of the Three Gorges Reservoir Region].

The flooding-drying cycles in the water-level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) result in an abundance of plants that are submerged and decomposed to release nutrients. This has the potential to lead to water quality deterioration of the TGR. Cynodon dactylon (Linn.) Pers., one of the typical plants in the WLFZ, was collected and inundated in the laboratory under different conditions under temperatures of 15℃ and 25℃, a pH 5.0 to 9.0, and under light and dark conditions, respectively, to measure the decomposition rate and nitrogen and phosphorus release mechanisms. The dry weight lost with the contents of nitrogen and phosphorus was found to decrease after Cynodon dactylon (Linn.) Pers. was soaked for decomposition. The amount released of total nitrogen (TN) and total phosphorus (TP) at 25℃ for 200-days inundation was(2.66±0.29)g·kg-1 or(3.76±0.04)g·kg-1, respectively and at 15℃ was(0.79±0.03) g·kg-1 or (1.40±0.02) g·kg-1, respectively. When the pH of the water submerging the grass was 5.0, 7.0 and 9.0, the amount of TN released was (3.76±0.08) g·kg-1, (2.66±0.29) g·kg-1, and (2.55±0.12) g·kg-1, respectively while the amount of TP released was (1.53±0.04) g·kg-1, (0.79±0.03) g·kg-1, and (1.70±0.07) g·kg-1, respectively. The TN and TP released was (3.87±0.14) g·kg-1 and (1.78±0.08) g·kg-1 under dark condition. The lower the temperature, the higher the amount of TN and TP will be released for inundation from Cynodon dactylon (Linn.) Pers. When the overlying water is acidic or alkaline, more TN and TP is released. Dark conditions are beneficial to nitrogen and phosphorus release into the overlying water. Thus, the water environment changes in each flooding season in winter. Sewage discharge will also accelerate the nutrients released from soaked plants through their decomposition in the WLFZ, and then will aggravate the deterioration of water quality in TGR.

Long non-coding RNA MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in colorectal cancer cells.

Our earlier findings indicate that the long non-coding RNA MALAT1 promotes colorectal cancer (CRC) cell proliferation, invasion and metastasis in vitro and in vivo by increasing expression of AKAP-9. In the present study, we investigated the molecular mechanism by which MALAT1 enhances AKAP9 expression in CRC SW480 cells. We found that MALAT1 interacts with both SRPK1 and SRSF1. MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation. Following MALAT1 knockdown, overexpression of SRPK1 was sufficient to restore SRSF1 phosphorylation and AKAP-9 expression to a level that promoted cell proliferation, invasion and migration in vitro. Conversely, SRPK1 knockdown after overexpression of MALAT1 in SW480 cells diminished SRSF1 phosphorylation and AKAP-9 expression and suppressed cell proliferation, invasion and migration in vitro. These findings suggest MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in CRC cells. These results reveal a novel molecular mechanism by which MALAT1 regulates AKAP-9 expression in CRC cells.

The role of integrin-ß/FAK in cyclic mechanical stimulation in MG-63 cells.

OBJECTIVE: This study aims to explore the function of Integrin-ß/FAK in the mechanical signal transduction and the connection with downstream ERK signal pathways. METHODS: Human osteosarcoma MG63 cell lines were used in this study. The effects of mechanical strain on the Integrin-ß1 expression, FAK and ERK signal pathway in Human osteosarcoma MG63 cells were detected using RT-PCR and Western-blotting methods. The localization of FAK in Human osteosarcoma MG63 cells were determined using immunofluorescent method. The interaction between Integrin-ß1 and FAK were detected by using co-immunoprecipitation method. RESULTS: The expression of Integrin-ß1 shows a notable bimodel distribution, mechanical strain stimulation can promote Integrin-ß1 expression and the phosphorylation of FAK and ERK, mechanical strain activated FAK and ERK mediated by Integrin-ß1. CONCLUSION: Integrin-ß1 may play an important role in osteoblast proliferation differentiation process, it might feel external strain stimulation through ECM composition and makes FAK phosphated through the interaction with FAK, thus causing a series of activation of signal molecules. Finally it reduces MAPK (ERK) activation and cellular responses to finish mechanical signal transduction.

[Influence of orthodontic force on osteoprotegerin and osteoprotegerin ligand mRNA expression in the inflammatory periodontal tissues].

OBJECTIVE: To explore certain principle of how osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) take part in the periodontal tissues remodeling under the combined influence of inflammation and orthodontic force. METHODS: The positive signals of OPG and OPGL mRNA were measured with in situ hybridzation after orthodontic tooth movement in the experimental periodontitis groups and control ones. RESULTS: The OPG and OPGL mRNA expression intensity in the experimental group showed difference from control. All their optical density index reached a peak in day 2, respectively. CONCLUSION: OPG and OPGL play important roles in the periodontal reconstruction induced by inflammation irritation and orthodontic force, and complex interaction could exist between the two factors.

[Integrin 3 mRNA changes after orthodontic teeth movement in periodontitis rats].

OBJECTIVE: To study the integrin beta3 mRNA changes after orthodontic treatment on normal teeth and periodontitis teeth in rats. METHODS: 96 adult SD rats of 10 weeks old were randomly divided into normal tooth move-ment group and periodontitis tooth movement group. The rats in the two groups were sacrificed after 0 d, 12 h, 1 d, 3 d, 5 d and 7 d of tooth movement. The alveolar specimens were prepared. The integrin beta3 mRNA were detected using in situ hybridization in the specimens. The OD index of positively stained osteoclasts for integrin beta3 mRNA after orthodontic tooth movement in the two groups were measured and compared. RESULTS: There were weak positive signals on the cytoplasm of osteoclasts in periodontum in both groups after 12 hours and 3 days force activation. No positive signals were detected in the rest samples. There was no difference in the OD of positive stained osteoclasts between normal and periodontitis groups. Strong expressions were present on cells with one or two nuclei in the alveolar marrow. CONCLUSION: It is suggested that integrin beta3 mRNA is related with osteoclasts maturation and migration in orthodontic tooth movement.

[The integrin beta1 mRNA changes after orthodontic movement of teeth in periodontitis rats].

OBJECTIVE: To study the integrin beta1 mRNA changes after orthodontic tooth movement in normal teeth and periodontitis teeth of rats. METHODS: The OD of positively stained osteoclasts for integrin beta1 mRNA using in situ hybridzation was detected after orthodontic tooth movement in normal teeth and periodontitis teeth groups. RESULTS: Integrin beta1 mRNA expression were detected on all osteoclasts in tooth movement samples of normal and periodontitis teeth. There were stronger positive signals after given orthodontic force in both of the two groups. But no differences were found after 0.5, 1, 2, 3, 5, 7, 10 days since orthodontic tooth movement. The integrin beta1 mRNA signals in normal tooth movement group were not different from that in periodontitis group. CONCLUSION: The integrin beta1 of osteoclasts may play a role in the stability and remodeling of periodontal ligament in orthodontic tooth movement. There were no difference in the OD of integrin beta1 mRNA staining in orthodontic tooth movement between normal teeth group and periodontitis teeth group.

[The clinic skill in fixed appliance based on characteristics of Chinese normal occlusion].

OBJECTIVE: To study the bracket placement and arch wire bending based on ethnic differences and individual differences of normal occlusion. METHODS: The prominence, tip, torque, upper first molar offset of crown and arch form between Chinese and Caucasian normal occlusion were compared. RESULTS: The results showed the ethnic differences of prominence, tip, torque, upper first molar offset of crown and arch form between Chinese and Caucasian normal occlusion. The placement of bracket was influenced by the crown morphology. CONCLUSION: The adjustments of the bracket placement and arch wire bending with Edgewise and pre-adjusted appliance are necessary to adapt to ethnic difference and individual difference.

[A comparative study of the bracket bond failure between adults and adolescents receiving fixed orthodontic therapy].

OBJECTIVE: To evaluate the bracket bond failure and its causes between adult and adolescent patients during fixed orthodontic therapy. METHODS: Bracket bond failure data of 30 adults and 30 adolescents, receiving fixed orthodontic therapy, have been collected within the first 12 visits, respectively. The compliance has been analyzed with survival analyse between the two groups. RESULT: The general bracket bond failure rate in the adult group is lower than that of the adolescent group and the difference is significant (p < 0.05). In the adolescent group, the failure rate for mandibular anterior teeth is highest and different from that of the adult group (p < 0.05). The failure rate resulted from biting hard food is ranked No. 1. CONCLUSIONS: The compliance of the adults receiving fixed orthodontic therapy is better than that of the adolescents. The investigation of bracket bond failure causes is beneficial in helping orthodontists improve orthodontic practice and raise clinical efficiency. The survival analysis is effective in evaluating the bond failure.