METTL3 modulates m6A modification of CDC25B and promotes head and neck squamous cell carcinoma malignant progression.

BACKGROUND: N6-methyladenosine (m6A) RNA methylation and its methyltransferase METTL3 have been widely reported to be involved in different cancers by regulating RNA metabolism and function. Here, we aimed to explore the biological function and clinical significance of m6A modification and METTL3 in head and neck squamous cell carcinoma (HNSCC). METHODS: The prognostic value of METTL3 expression was evaluated using tissue microarray and immunohistochemical staining analyses in a human HNSCC cohort. The biological role and mechanism of METTL3 in HNSCC tumour growth, metastasis and angiogenesis were determined in vitro and in vivo. RESULTS: M6A levels and METTL3 expressions in HNSCC tissues were significantly increased compared with paired adjacent tissues. Meanwhile, METTL3 was an independent risk factor for the prognosis of HNSCC patients. Moreover, METTL3 overexpression promoted HNSCC cell proliferation, migration, invasion, and angiogenesis, while knockdown of METTL3 had an opposite effect in vivo and in vitro. Mechanistically, METTL3 enhanced the m6A modification of CDC25B mRNA, which maintained its stability and upregulated its expression, thereby activating G2/M phase of cell cycle and leading to HNSCC malignant progression. CONCLUSIONS: METTL3 may be a potential prognostic biomarker and therapeutic target for HNSCC.

Clinical utility and effectiveness of a training programme in the application of a new classification of narrow-band imaging for vocal cord leukoplakia: A multicentre study.

OBJECTIVE: To analyse the application of a new narrow-band imaging (NBI) classification in the diagnosis of vocal cord leukoplakia by laryngologists with different levels of laryngoscopic experience and to explore the impact of NBI training programmes on laryngologists' identification of benign and malignant leukoplakia. DESIGN: Prospective multicentre study. SETTING: Tertiary hospitals. PARTICIPANTS: Sixteen laryngologists were divided into less-experienced and experienced groups and received NBI training course. Thirty cases of vocal cord leukoplakia were investigated. MAIN OUTCOME MEASURES: Diagnostic accuracy and interobserver agreement under white light imaging (WLI), before and after NBI training, were analysed among doctors with varying levels of experience. RESULTS: The accuracy in the less-experienced group was significantly lower than that of experience group (0.59 vs 0.69) under WLI. There was no significant difference in the diagnostic accuracy between the less-experienced group and the experienced group before NBI training (0.75 vs 0.74) and after NBI training (0.79 vs 0.83). NBI training could improve the interobserver agreement from fair or moderate to good agreement. CONCLUSION: The new NBI diagnostic classification is helpful for identifying benign and malignant vocal cord leukoplakia. In addition, the NBI training programme can improve the diagnostic accuracy and interobserver agreement of less-experienced doctors to the level of experienced laryngologists.

Role of epithelial-mesenchymal transition markers E-cadherin, N-cadherin, ß-catenin and ZEB2 in laryngeal squamous cell carcinoma.

Epithelial-mesenchymal transition (EMT) allows neoplastic cells to gain the invasive phenotype and become migratory, which is required for cancer progression and metastasis. In the present study, the expression of EMT-associated biomarkers and their association with clinicopathological parameters in laryngeal squamous cell carcinoma (LSCC) was investigated. E-cadherin, N-cadherin, ß-catenin and zinc finger E-box binding homeobox 2 (ZEB2) protein expression was evaluated with immunohistochemistry in a cohort of 76 patients with operable LSCC. The association between these transition markers, clinicopathological parameters and their prognostic impact in LSCC was analyzed. Immunohistochemical analysis revealed that EMT-associated proteins were differentially expressed between LSCC and adjacent non-neoplastic laryngeal tissue. Negative E-cadherin expression and positive N-cadherin, ß-catenin and ZEB2 expression were associated with a later tumor (T) stage, decreasing tumor differentiation and a reduced overall survival (OS) time (OS: E-cadherin, P=0.016; N-cadherin, P=0.003; ß-catenin, P=0.002; ZEB2, P=0.0003). E-cadherin/ß-catenin co-expression was significantly associated with the majority of clinicopathological parameters assessed, including lymph node metastases, T stage and tumor cell differentiation (P=0.004, P=0.005, and P<0.001, respectively). Multivariate analysis indicated that T stage and the positive expression of ß-catenin and ZEB2 were independent risk factors for OS in LSCC (P=0.014, P=0.025 and P=0.003, respectively). It was concluded that EMT mediates tumor progression, and reduces OS time in patients with LSCC. E-cadherin/ß-catenin co-expression may be associated with clinicopathological parameters. T stage, and the positive co-expression of ß-catenin and ZEB2 may be independent predictors of prognosis in LSCC.

Prediction of Lymph Node Metastases in Gastric Cancer by Serum APE1 Expression.

Aims: To investigate the functional role of serum Human apurinic/apyrimidinic endonuclease 1 (APE1) in prediction of lymph node metastasis in gastric cancer patients. Materials and methods: Serum samples were pre-operational collected from 86 patients with gastric cancer from Tianjin Medical University Cancer Institute and Hospital from March 2016 to August 2016. The serum of APE1 was measured by ELISA development kit and other CA242, CA724, CA199 and CEA levels by electrochemiluminescence assay. Results: The total of 86 patients with gastric cancer was classified into two groups (lymph node positive and negative groups). Using ELISA assay, we found out that the concentration of serum APE1 was higher in lymph node positive group than that of lymph node negative group. The receiver operating characteristic (ROC) curve was performed to analyze, indicating that area under the ROC curve of serum APE1 were better than those of each regular markers (CEA+CA199+CA242+CA724) or combination of these markers. Additionally, the APE1 overexpression was uncovered in tissue of gastric cancer patients with lymph nodes metastases, which is correlation with results of serum APE1. Conclusion: Serum APE1 was identified as a valuable marker for prediction of lymph node metastases in patients with gastric cancer.

A new D-dimer cutoff value to improve the exclusion of deep vein thrombosis in cancer patients.

OBJECTIVE: To find a more appropriate alternative to D-dimer cutoff value for the diagnosis of deep vein thrombosis (DVT) in cancer patients. METHODS: A total of 711 cancer patients with symptoms suspicious of DVT were included in the study. D-dimer levels were assessed using ELISA. All patients were subjected to imaging procedures. RESULTS: Among 711 patients with cancer, 466 (65.5%) were females and 245 (34.5%) were males, with an average age of 57.3 ± 13.23 years. The mean age in the DVT group was significantly higher than in the non-DVT group (P<0.05). The D-dimer levels of the DVT group were significantly higher than those of the non-DVT group (P<0.05). The incidence rate of DVT varied significantly according to cancer type (P<0.05). Increasing age and lung cancer were significantly correlated with D-dimer levels (P<0.05), and a one-year increase in age was associated with a 14.28 ng/ml increase in the D-dimer value. The optimal cutoff point for D-dimer was found to be 981 ng/ml, with a sensitivity of 86.4%, specificity of 79.4%, and accuracy of 82.6%. If the D-dimer cutoff point was set to 981 ng/ml, the specificity would increase from 61.8% to 85.5% without loss of sensitivity in patients aged 40 years or younger. In patients aged more than 40 years, the new cutoff almost doubled the specificity with slightly reduced sensitivity. CONCLUSION: In cancer patients, a new cutoff value of 981 ng/ml effectively improved the exclusion of DVT, especially for patients aged more than 40 years.

Inhibition of Myo6 gene expression by co­expression of a mutant of transcription factor POU4F3 (BRN­3C) in hair cells.

An eight­base pair (bp) deletion in the Pou4f3 gene in hair cells is associated with DFNA15, a hereditary form of hearing loss. To explore the pathological mechanisms underlying the development of DFNA15, the effect of the mutation in Pou4f3 on the activity of the myosin VI (Myo6) promoter, was investigated. The upstream regulatory sequence of Myo6 (2625 bp), consisting of an 1899 bp upstream sequence and a 727 bp intron 1 sequence, was amplified using polymerase chain reaction and subcloned into the pGL3­Basic vector expressing firefly luciferase. For verification of inserted fragments, plasmids were subjected to restriction analysis and then sequenced. HEK293T human embryonic kidney cells were transiently transfected with renilla luciferase­thymidine kinase vectors expressing Renilla luciferase and the Myo6 promoter­driven firefly luciferase expressing vectors along with pIRES2­enhanced green fluorescent protein (EGFP)­Pou4f3 (expressing wild­type Pou4f3) or pIRES2­EGFP­Pou4f3 (expressing the truncation mutant of Pou4f3). The relative luciferase activities were measured to determine the activity of the Myo6 promoter. The Myo6 promoter activity was not affected by co­expression of wild­type Pou4f3, as indicated by the comparable relative luciferase activities in the presence of the pIRES2­EGFP­Pou4f3 and the empty control vectors. However, co­expression of mutated Pou4f3 significantly inhibited the activity of the Myo6 promoter to almost half of that of the control (P<0.001). The data suggests that mutated Pou4f3 has a negative role in the promoter activity of Myo6, and by extension, the expression of myosin VI, and this may be an underlying mechanism of DFNA15 hearing loss.

Clinical and laboratory characteristics of patients having amyloidogenic transthyretin deposition in osteoarthritic knee joints.

OBJECTIVE: Our aim was to investigate clinical and laboratory characteristics of osteoarthritic patients who had amyloid deposition in their knee joints. METHODS: Synovial membranes were obtained from 36 patients with knee osteoarthritis (OA) who underwent joint replacement surgery. From this sample, the diagnosis of amyloid was determined by Congo red staining, which demonstrated apple-green birefringence under a polarized microscope. All synovial membranes were immunohistochemically characterized for the expressions of amyloid immunoglobulin light chain (AL-κ and AL-λ), serum amyloid-A (SAA), amyloidogenic transthyretin (ATTR), and amyloidogenic ß2-microglobulin (Aß2M). Matrix-assisted laser desorption-ionizaton/time of flight mass spectrometry (MALDI-TOF MS) was used to analyze transthyretin (TTR) isoforms in the serum of each patient. RESULTS: Nine cases (25%) were found to be amyloid-positive. Immunohistochemically, eight cases (88.9%) had ATTR deposition, and one sample (11.1%) was shown to be AL-κ-positive. MALDI-TOF MS identified that the TTR in the serum of the patients was unmodified wild-type TTR, TTR-Cys-S-S-Cys, and TTR-Cys-S-S-CysGly. The age at surgery and the disease duration were significantly higher in the ATTR-positive group than in the ATTR-negative group. Knee score and function score were significantly lower in the ATTR-positive group than in the ATTR-negative group. CONCLUSIONS: Amyloid deposition in synovial membranes of OA patients was found to be ATTR and AL-κ. TTR in the serum of the patients was unmodified wild-type TTR together with two isoforms. The high age at surgery, long disease duration, and a deteriorated knee function were associated with ATTR amyloid deposition in the osteoarthritic knee joints.

Transthyretin as a potential serological marker for the diagnosis of patients with early rheumatoid arthritis.

OBJECTIVES: To investigate the serum levels and modifications of transthyretin (TTR) in patients with rheumatoid arthritis (RA) by mass spectrometry, and the potential role of TTR in early RA. METHODS: Serum samples were collected from early RA (ERA), middle and late RA (LRA), osteoarthritis (OA) patients, and healthy controls (HC). Levels of TTR were measured by ELISA, and serum TTR was further detected by Western blot. A subsequent MALDI-TOF-MS was performed to analyse the modified TTR. RESULTS: Serum TTR levels in ERA (502.46±108.15 mg/l) was significantly higher than that of healthy controls (424.98±117.63 mg/l) (p<0.05). TTR levels in LRA was higher than that of HC but without statistical significance (p>0.05), and no statistical significance between OA (363.90±105.21mg/l) and HC (p>0.05). Two protein bands were identified corresponding to monomer and dimmer TTR by western blot. The proportion of TTR monomer was similar in each group. However, the proportion of TTR dimer in RA was lower than that in HC, which was decreased more in LRA (p<0.05). By MALDI-TOF-MS, four major peaks were observed in sera corresponding to native TTR (13749.86±1.48 m/z), Sul-TTR (13829.63±2.76 m/z), Cys-TTR (13870.70±2.70 m/z), and Cysgly-TTR (13927±5.77 m/z). The proportion of modified TTR varied with different disease stages. CONCLUSIONS: TTR levels in sera of patients with early RA were significantly increased. Four modified TTR were identified by MALDI-TOF-MS, and the proportion of modified TTR varied with different disease stages. Thus serum TTR could be considered as a potential serological marker for early diagnosis of RA.

[Purification and renaturation of recombinant human Cu, Zn-SOD by metal-chelating affinity chromatography].

Overexpression of recombinant Human Cu, Zn-Superoxide Dismutase (rhCu, Zn-SOD) in E. coli results in the form of insoluble inclusion body. Purity of rhSOD inclusion body was over 80% by isolation and purification. After preliminary renaturation by conventional dilution or dialysis, enzyme preparations was respectively purified by using Copper Metals-Chelating Affinity Chromatography (Copper-MCAC). RhSOD specific activity purified by MCAC (from the sample renatured partly by dialysis) was 2.2 times as much as that by dialysis and protein recovery was 64%. RhSOD specific activity purified by MCAC (from the sample renatured partly by dilution) was 5.3 times as much as that by dilution and protein recovery was 25%. The two rhSOD preparations purified by MCAC had specific activities about 5000 u/mg and activity recoveries were all over 130% of the enzyme activities in the samples renatured partly by dilution or dialysis. The above-mentioned results indicated that Copper-MCAC resulted in a purification and further renaturation of target protein. SDS-PAGE showed that the target protein rhSOD (19 kD) was purified homogeneously and NBT activity identification proved that the purified and renatured rhSOD had very strong SOD activity. In conclusion, Copper Metals-Chelaing Affinity Chromatography appears to be a simple, rapid and efficient procedure for purifying and further renaturing rhCu, Zn-SOD by dilution or dialysis. The method provided a new idea for purifying and renaturing recombinant proteins expressed in the form of inclusion body in E. coli.